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Diseases

Genetic and Rare Diseases Information Center (GARD)

Search for Rare or Genetic Diseases


Diseases Beginning With M

The purpose of the Rare Diseases and Related Terms list is to distribute information; although the list is updated regularly, it should not be used as a reference or guarantee that a condition is rare. The prevalence of a rare disease is usually an estimate and may change over time. A rare (or orphan) disease is generally considered to have a prevalence of fewer than 200,000 affected individuals in the United States.

* This symbol indicates that a condition is not rare but is one for which a question has been answered by the GARD Information Center.

Is Rare Condition? Disease Name
* M. Abscessus - See Mycobacterium Abscessus
* M. Avium - See Mycobacterium Avium Complex
* M. Chelonae - See Mycobacterium Chelonae
* M. Fortuitum - See Mycobacterium fortuitum
* M. Gordonae - See Mycobacterium Gordonae
* M. Intracellulare - See Mycobacterium Avium Complex
* M. Kansasii - See Mycobacterium Kansasii
* M. Malmoense - See Mycobacterium Malmoense
* M. Marinum - See Mycobacterium Marinum
* M. Xenopi - See Mycobacterium Xenopi
* M/SCHAD - See 3-alpha hydroxyacyl-CoA dehydrogenase deficiency
* M-A - See Microtia-Anotia
* MAA (formerly) - See Lenz microphthalmia syndrome
* MAA2 (formerly) - See Oculofaciocardiodental syndrome
* MAC - See Microcystic adnexal carcinoma
* MAC - See Mycobacterium Avium Complex
* Mac Dermot Winter syndrome
* Maccario Mena Weir syndrome - See Neuroaxonal dystrophy renal tubular acidosis
* Macdermot-Winter syndrome - See Mac Dermot Winter syndrome
* Machado Joseph disease - See Spinocerebellar ataxia 3
* Macias-Flores Garcia-Cruz Rivera syndrome - See Hypertrichosis congenital generalized X-linked
* MacKay Shek Carr syndrome - See Retinal degeneration with nanophthalmos, cystic macular degeneration, and angle closure glaucoma
* Macrencephaly - See Hemimegalencephaly
* Macrocephaly cutis marmorata telangiectatica congenita - See Macrocephaly-capillary malformation
* Macrocephaly mesodermal hamartoma spectrum
* Macrocephaly multiple lipomas and hemangiomata - See Bannayan-Riley-Ruvalcaba syndrome
* Macrocephaly pseudopapilledema and multiple hemangiomas - See Bannayan-Riley-Ruvalcaba syndrome
* Macrocephaly short limbs deafness - See Bagatelle Cassidy syndrome
* Macrocephaly, benign familial
* Macrocephaly, brachycephaly, depressed nasal bridge, hypertelorism, thick eyebrows/scalp hair, short stature/neck, seizures, progressive dementia - See Fucosidosis type 1
* Macrocephaly, hypertelorism, short limbs, hearing loss, and developmental delay - See Bagatelle Cassidy syndrome
* Macrocephaly, mental retardation, short stature, spastic paraplegia and CNS malformations
* Macrocephaly-capillary malformation
* Macrocrania, obesity, ocular abnormalities (retinal coloboma and nystagmus) - See MOMO syndrome
* Macrodactyly of the foot
* Macrodactyly of the hand
* Macroepiphyseal dysplasia with osteoporosis, wrinkled skin, and aged appearance
* Macroepiphyseal dysplasia, McAlister Coe type - See Macroepiphyseal dysplasia with osteoporosis, wrinkled skin, and aged appearance
* Macroglobulinemia of Waldenstrom - See Waldenstrom macroglobulinemia
* Macroglossia
* Macrogyria - See Pachygyria
* Macrogyria, pseudobulbar palsy and mental retardation
* Macromastia - See Gigantomastia
* Macrophage activation syndrome
* Macrophagic myofasciitis
* Macrophagic myofasciitis, childhood - See Macrophagic myofasciitis
* Macrosomia microphthalmia cleft palate - See Macrosomia with lethal microphthalmia
* Macrosomia with lethal microphthalmia
* Macrosomia, obesity, macrocephaly, ocular abnormalities - See MOMO syndrome
* Macrothrombocytopenia progressive deafness
* Macrothrombocytopenia, familial Bernard-Soulier type - See Giant platelet syndrome
* Macular coloboma - See Coloboma of macula
* Macular corneal dystrophy type 1 - See Macular dystrophy, corneal type 1
*   Macular degeneration
* Macular degeneration, polymorphic vitelline - See Best vitelliform macular dystrophy
* Macular dystrophy retinal 1 North Carolina type - See North Carolina macular dystrophy
* Macular dystrophy, atypical vitelliform
* Macular dystrophy, butterfly-shaped pigmentary - See Patterned dystrophy of retinal pigment epithelium
* Macular dystrophy, concentric annular
* Macular dystrophy, corneal type 1
* Macular dystrophy, hemorrhagic - See Fundus dystrophy, pseudoinflammatory, of Sorsby
* Macular dystrophy, vitelliform, adult-onset - See Adult-onset vitelliform macular dystrophy
* Macules hereditary congenital hypopigmented and hyperpigmented
* Maculopathy, bull's eye - See Macular dystrophy, concentric annular
* MAD - See Mandibuloacral dysplasia
* MAD - See Metaphyseal anadysplasia
* MADA - See Mandibuloacral dysplasia with type A lipodystrophy
* MADB - See Mandibuloacral dysplasia with type B lipodystrophy
* MADD - See Glutaric acidemia type II
* Madelung disease
* Madelung's disease - See Madelung disease
* Madokoro Ohdo Sonoda syndrome
*   Madras motor neuron disease
* Maeda syndrome - See Cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy
* Maffucci syndrome
* Maghrebian myopathy - See Limb-girdle muscular dystrophy, type 2C
* Magnesium loss, isolated renal - See Hypomagnesemia 2, renal
* Magnesium wasting, renal - See Hypomagnesemia 2, renal
* Magnesium, defect in renal tubular transport of - See Hypomagnesemia primary
* Mahvash disease
* MAI - See Mycobacterium Avium Complex
* Mainzer Saldino syndrome - See Renal dysplasia, retinal pigmentary dystrophy, cerebellar ataxia and skeletal dysplasia
* MAIS - See Androgen insensitivity syndrome, mild
* Majeed syndrome
* Majewski osteodysplastic primordial dwarfism type II - See Microcephalic osteodysplastic primordial dwarfism type 2
* Majewski syndrome - See Short rib-polydactyly syndrome type 2
*   Major affective disorder - See Bipolar disorder
* Major Aphthous Ulcer - See Sutton disease 2
* Major Canker Sore - See Sutton disease 2
* Major histocompatibility complex class 1 deficiency - See MHC class 1 deficiency
* Mal de debarquement
* Mal de debarquement syndrome - See Mal de debarquement
* Mal de Meleda - See Meleda disease
* Mal de Naxos - See Naxos disease
* Mal del Pinto - See Pinta
* Malacoplakia - See Malakoplakia
* Maladie de Sprengel familiale - See Sprengel deformity
* Malakoplakia
* Malaria
* Malayi tropical eosinphilia - See Lymphatic filariasis
* Male breast cancer - See Breast cancer, male
* Male breast carcinoma - See Breast cancer, male
* Male pseudohermaphroditism due to 5-alpha-reductase deficiency - See 5-alpha reductase deficiency
* Male pseudohermaphroditism due to defective LH molecule
* Male pseudohermaphroditism intellectual disability syndrome, Verloes type
* Male pseudoherma-phroditism with gynecomastia - See 17-beta hydroxysteroid dehydrogenase 3 deficiency
* Male sterility due to Y-chromosome deletions - See Y chromosome infertility
* Male Turner Syndrome - See Noonan syndrome
* Malignant acrospiroma - See Hidradenocarcinoma
* Malignant astrocytoma - See Anaplastic astrocytoma
* Malignant atrophic papulosis - See Degos disease
* Malignant clear cell acrospiroma - See Hidradenocarcinoma
* Malignant cylindroma
* Malignant eccrine spiradenoma
* Malignant edema - See Anthrax
* Malignant fibrohistiocytic tumors - See Malignant fibrous histiocytoma
* Malignant fibrous histiocytoma
* Malignant germ cell tumor
* Malignant hyperpyrexia - See Malignant hyperthermia
* Malignant hyperpyrexia susceptibility type 2 - See Malignant hyperthermia susceptibility type 2
* Malignant hyperpyrexia susceptibility type 3 - See Malignant hyperthermia susceptibility type 3
* Malignant hyperpyrexia susceptibility type 4 - See Malignant hyperthermia susceptibility type 4
* Malignant hyperpyrexia susceptibility type 5 - See Malignant hyperthermia susceptibility type 5
* Malignant hyperpyrexia susceptibility type 6 - See Malignant hyperthermia susceptibility type 6
* Malignant hyperthermia
* Malignant hyperthermia - arthrogryposis - torticollis - See Malignant hyperthermia arthrogryposis torticollis
* Malignant hyperthermia arthrogryposis torticollis
* Malignant hyperthermia susceptibility type 1
* Malignant hyperthermia susceptibility type 2
* Malignant hyperthermia susceptibility type 3
* Malignant hyperthermia susceptibility type 4
* Malignant hyperthermia susceptibility type 5
* Malignant hyperthermia susceptibility type 6
* Malignant islet cell tumor - See Somatostatinoma
* Malignant Langerhans cell sarcoma - See Langerhans cell sarcoma
* Malignant melanoma of the gastrointestinal tract - See Primary gastrointestinal melanoma
* Malignant melanoma, childhood
* Malignant mesenchymal tumor
* Malignant mesenchymoma - See Malignant mesenchymal tumor
* Malignant mesothelioma
* Malignant mixed Mullerian tumor
* Malignant mixed mullerian tumor of the ovary - See Ovarian carcinosarcoma
* Malignant myoepithelioma - See Myoepithelial carcinoma
* Malignant neoplasms of the small intestine - See Small intestine cancer
* Malignant nodular/clear cell hidradenoma - See Hidradenocarcinoma
* Malignant paroxysmal ventricular tachycardia - See Catecholaminergic polymorphic ventricular tachycardia
* Malignant peripheral nerve sheath tumor
* Malignant phyllodes tumor of prostate (subtype) - See Phyllodes tumor of the prostate
* Malignant pustule - See Anthrax
* Malignant Teratocarcinosarcoma
* Malignant tumors of the central nervous system associated with familial polyposis of the colon - See Turcot syndrome
* Malignant variant of Abrikosov's tumor - See Abrikosov's tumor
* Mallory-Weiss laceration - See Mallory-Weiss syndrome
* Mallory-Weiss syndrome
* Mallory-Weiss tear - See Mallory-Weiss syndrome
* Malonic acidemia - See Malonyl-CoA decarboxylase deficiency
* Malonic aciduria - See Malonyl-CoA decarboxylase deficiency
* Malonicaciduria - See Malonyl-CoA decarboxylase deficiency
* Malonyl-CoA decarboxylase deficiency
* Malouf syndrome - See Dilated cardiomyopathy with hypergonadotropic hypogonadism
* Malpuech facial clefting syndrome
* Malpuech syndrome - See Malpuech facial clefting syndrome
* Malta fever - See Brucellosis
* Mammary hypoplasia, ectrodactyly, and other hand/foot anomalies - See Limb-mammary syndrome
* Mammary Paget's disease - See Paget disease of the breast
*   Mammary pseudoangiomatous stromal hyperplasia - See Pseudoangiomatous stromal hyperplasia
* Mandibular hypoplasia, deafness, progeroid features - See MDP syndrome
* Mandibuloacral dysplasia
* Mandibuloacral dysplasia with type A lipodystrophy
* Mandibuloacral dysplasia with type B lipodystrophy
* Mandibulofacial dysostosis - See Treacher Collins syndrome
* Mandibulofacial dysostosis Toriello type - See Branchial arch syndrome X-linked
* Mandibulofacial dysostosis, Treacher Collins type, autosomal recessive - See Treacher Collins syndrome 3
* Mandibulofacial dysostosis, Treacher Collins type, with limb anomalies - See Nager acrofacial dysostosis
*   Manic depression - See Bipolar disorder
*   Manic-depressive psychosis - See Bipolar disorder
* Manitoba oculotrichoanal syndrome
* Manitoba Trichoanal syndrome - See Manitoba oculotrichoanal syndrome
*   Mannose-binding lectin protein deficiency
*   Mannose-binding protein deficiency - See Mannose-binding lectin protein deficiency
* Mannosephosphate isomerase deficiency - See Congenital disorder of glycosylation type 1B
* Mannosidosis, alpha B lysosomal - See Alpha-mannosidosis type 1
* Mannosidosis, beta A, lysosomal
* Manouvrier syndrome
* Mansonella perstans - See Acanthocheilonemiasis
* Mansonella perstans infections - See Mansonelliasis
* Mansonelliasis
* Mansonellosis - See Mansonelliasis
* Mantle cell lymphoma
* Manz syndrome
* MAP syndrome - See MYH-associated polyposis
* Map-dot-fingerprint dystrophy of cornea - See Epithelial basement membrane corneal dystrophy
* Maple syrup urine disease
* Maple syrup urine disease type 1A
* Maple syrup urine disease type 1B
* Maple syrup urine disease type 2
* MAR - See 5q- syndrome
* Marble bone disease - See Osteopetrosis
* Marble bones - See Osteopetrosis
* Marble bones autosomal recessive - See Osteopetrosis autosomal recessive 1
* Marble brain disease - See Osteopetrosis autosomal recessive 3
* Marburg disease - See Marburg hemorrhagic fever
* Marburg hemorrhagic fever
* Marburg virus disease - See Marburg hemorrhagic fever
* Marchiafava Bignami disease
* Marchiafava-Micheli disease - See Paroxysmal nocturnal hemoglobinuria
* Marcus Gunn phenomenon
* Marcus Gunn syndrome - See Marcus Gunn phenomenon
* Marden Walker like syndrome
* Marden Walker like syndrome without psychomotor retardation - See Marden Walker like syndrome
* Marden-Walker syndrome
* Marek disease
* Marek's Disease - See Marek disease
* Marfan syndrome
* Marfan syndrome type 1 - See Marfan syndrome
* Marfan syndrome, type 2 (formerly) - See Loeys-Dietz syndrome type 2B
* Marfanoid craniosynostosis syndrome - See Shprintzen-Goldberg craniosynostosis syndrome
* Marfanoid disorder with craniosynostosis type 1 - See Shprintzen-Goldberg craniosynostosis syndrome
* Marfanoid habitus, mild general hypotonia, hypernasal voice, normal testicular size and distinct craniofacial anomalies - See Lujan Fryns syndrome
* Marfanoid hypermobility syndrome
* Marfanoid mental retardation syndrome autosomal
* Marfanoid-craniosynostosis syndrome - See Shprintzen-Goldberg craniosynostosis syndrome
* Marfan's disease and familial neuropathy - See Tome Brunet Fardeau syndrome
*   Marginal alopecia - See Alopecia areata
* Marginal glioneuronal heterotopia
* Mari type Alopecia universalis congenita - See Total Hypotrichosis, Mari type
* Marie type ataxia
* Marie Unna congenital hypotrichosis
* Marie Unna hereditary hypotrichosis - See Marie Unna congenital hypotrichosis
* Marie's ataxia - See Marie type ataxia
* Marie-Sainton disease - See Cleidocranial dysplasia
* Marinesco-Garland Syndrome - See Marinesco-Sjogren syndrome
* Marinesco-Sjogren syndrome
* Marinesco-Sjogren Syndrome-Hypergonadotrophic Hypogonadism - See Marinesco-Sjogren syndrome
* Marinesco-Sjogren Syndrome-Myopathy - See Marinesco-Sjogren syndrome
* Marinesco-Sjogren-Garland Syndrome - See Marinesco-Sjogren syndrome
* Marinesco-Sjogren-like syndrome (MSLS)
* Marked decrease or absence of alpha-granules and of platelet-specific alpha-granule proteins - See Gray platelet syndrome
* Markel Vikkula Mulliken syndrome
* Marker X syndrome - See Fragile X syndrome
* Marles syndrome - See Manitoba oculotrichoanal syndrome
* Marles-Greenberg-Persaud syndrome - See Manitoba oculotrichoanal syndrome
* Maroteaux Fonfria syndrome
* Maroteaux Lamy syndrome - See Mucopolysaccharidosis type VI
* Maroteaux Le Merrer Bensahel syndrome - See Carpotarsal osteochondromatosis
* Maroteaux Stanescu Cousin syndrome
* Maroteaux Verloes Stanescu syndrome - See Metaphyseal anadysplasia
* Maroteaux-Malamut syndrome - See Acrodysostosis
* Marphanoid syndrome type De Silva
* Marrow hypoplasia associated with congenital neurologic anomalies - See Drachtman Weinblatt Sitarz syndrome
* Marsden Nyhan Sakati syndrome
* Marsden syndrome - See Leber hereditary optic neuropathy with dystonia
* Marshall syndrome
* Marshall Syndrome - See Periodic fever, aphthous stomatitis, pharyngitis and adenitis
* Marshall-Smith syndrome
* Martin-Bell syndrome - See Fragile X syndrome
* Martinez Frias syndrome - See Frias syndrome
* Martinez Monasterio Pinheiro syndrome
* Martsolf syndrome
* MAS - See McCune Albright syndrome
* MAS - See Meconium aspiration syndrome
* MASA syndrome - See Spastic paraplegia 1
* Mason type diabetes - See Maturity-onset diabetes of the young
* MASS phenotype - See MASS syndrome
* MASS syndrome
* Massa Casaer Ceulemans syndrome
* Massive macronodular adrenocortical disease - See ACTH-independent macronodular adrenal hyperplasia
* Masson's pseudoangiosarcoma - See Intravascular papillary endothelial hyperplasia
* Masson's tumor - See Intravascular papillary endothelial hyperplasia
* Masson's vegetant intravascular hemangio-endothelioma - See Intravascular papillary endothelial hyperplasia
* Mast cell disease - See Mastocytosis
* Mast cell leukemia - See Systemic mastocytosis
* Mastocytic enterocolitis
* Mastocytoma - See Cutaneous mastocytosis
* Mastocytosis
* Mastocytosis cutaneous with short stature conductive hearing loss and microtia
* Mastroiacovo De Rosa Satta syndrome
* Mastroiacovo Gambi Segni syndrome
* MAT deficiency - See Methionine adenosyltransferase deficiency
* Maternal hyperphenylalaninemia
* Maternal phenylketonuria - See Maternal hyperphenylalaninemia
* Maternal uniparental disomy of chromosome 13 - See Uniparental disomy of 13
* Maternally inherited diabetes and deafness
* Maternally inherited Leigh syndrome
* Maternofetal infection by parvovirus - See Parvovirus antenatal infection
* Mathieu-De Broca-Bony syndrome - See Cleft palate short stature vertebral anomalies
* Matsoukas Liarikos Giannika syndrome
* Matthew Wood syndrome - See Microphthalmia syndromic 9
* Maturity-onset diabetes of the young
* Maturity-onset diabetes of the young, type 1
* Maturity-onset diabetes of the young, type 2
* Maturity-onset diabetes of the young, type 3
* Maturity-onset diabetes of the young, type 4
* Maturity-onset diabetes of the young, type 5
* Maturity-onset diabetes of the young, type 6
* Maturity-onset diabetes of the young, type 7
* Maturity-onset diabetes of the young, type 8
* Maturity-onset diabetes of the young, type 8, with exocrine dysfunction - See Maturity-onset diabetes of the young, type 8
* Maturity-onset diabetes of the young, type 9
* Maumenee corneal dystrophy - See Corneal endothelial dystrophy type 2
* Maumenee syndrome
* Maxillary double lip
* Maxillofacial dysostosis
* Maxillonasal dysplasia, Binder type
* Maxillopalpebral synkinesis - See Marcus Gunn phenomenon
* Mayer Rokitansky Kuster Hauser syndrome - See Mayer-Rokitansky-Kuster-Hauser syndrome
* Mayer-Rokitansky-Kuster-Hauser syndrome
* May-Hegglin anomaly - See MYH9 related thrombocytopenia
* May–Thurner syndrome
* MBD - See Marchiafava Bignami disease
*   MBL deficiency - See Mannose-binding lectin protein deficiency
* MBS - See Moebius syndrome
* MBS2 (formerly) - See Hereditary congenital facial paresis
* MCA/MR syndrome with hypocholesterolemia due to familial hypobetalipoproteinemia - See Nguyen syndrome
* MCAD deficiency - See Medium-chain acyl-coenzyme A dehydrogenase deficiency
* MCADD - See Medium-chain acyl-coenzyme A dehydrogenase deficiency
* MCADH deficiency - See Medium-chain acyl-coenzyme A dehydrogenase deficiency
* McAlister Coe Whyte syndrome - See Macroepiphyseal dysplasia with osteoporosis, wrinkled skin, and aged appearance
* McAlister-Crane syndrome - See Lethal short-limb dwarfism, McAlister-Crane type
* McArdle disease - See Glycogen storage disease type 5
* McArdle type glycogen storage disease - See Glycogen storage disease type 5
* MCC 1 deficiency - See 3 Methylcrotonyl-CoA carboxylase 1 deficiency
* MCC 2 deficiency - See 3 alpha methylcrotonyl-CoA carboxylase 2 deficiency
* MCC deficiency - See 3-methylcrotonyl-CoA carboxylase deficiency
* Mccabe disease - See Polyostotic osteolytic dysplasia, hereditary expansile
* McCallum Macadam Johnston syndrome
* MCCD - See 3-methylcrotonyl-CoA carboxylase deficiency
* McCune Albright syndrome
* MCD - See Multicentric Castleman’s Disease
* MCD deficiency - See Malonyl-CoA decarboxylase deficiency
* MCDC1 - See Macular dystrophy, corneal type 1
* MCDCA - See Macular dystrophy, concentric annular
* McDonough syndrome
* McDowall syndrome
* MCDR1 - See North Carolina macular dystrophy
* MCDS - See Metaphyseal chondrodysplasia Schmid type
* MCDS - See Metaphyseal chondrodysplasia Spahr type
* McGillivray syndrome
* Mcgrath syndrome - See Ectodermal dysplasia skin fragility syndrome
* MCKAT deficiency - See Medium-chain 3-ketoacyl-coa thiolase deficiency
* MCKD - See Medullary cystic kidney disease
* MCKD1 - See Medullary cystic kidney disease 1
* MCKD2 - See Medullary cystic kidney disease 2
* McKusick Kaufman syndrome
* MCL - See Hereditary leiomyomatosis and renal cell cancer
* McLeod neuroacanthocytosis syndrome
* McLeod syndrome - See McLeod neuroacanthocytosis syndrome
* M-CM - See Macrocephaly-capillary malformation
* MCM Deficiency - See Methylmalonyl-Coenzyme A mutase deficiency
* M-CMTC - See Macrocephaly-capillary malformation
* MCNS - See Minimal change disease
* MCOPCR - See Microphthalmia, isolated, with corectopia
* MCOPS1 - See Lenz microphthalmia syndrome
* MCOPS10 - See Microphthalmia syndromic 10
* MCOPS2 - See Oculofaciocardiodental syndrome
* MCOPS3 - See Microphthalmia syndromic 3
* MCOPS4 - See Microphthalmia syndromic 4
* MCOPS5 - See Microphthalmia syndromic 5
* MCOPS6 - See Microphthalmia syndromic 6
* MCOPS7 - See Microphthalmia syndromic 7
* MCOPS8 - See Microphthalmia syndromic 8
* MCOPS9 - See Microphthalmia syndromic 9
* MCOR - See Microcoria, congenital
* MCPH syndrome - See Microcephaly, primary autosomal recessive
* MCPHA - See Amish lethal microcephaly
* McPherson Clemens syndrome
* McPherson Robertson Cammarano syndrome
* MCS - See Miles-Carpenter x-linked mental retardation syndrome
* MCSZ - See Microcephaly, seizures, and developmental delay
* MCTD - See Mixed connective tissue disease
* MCUL - See Hereditary leiomyomatosis and renal cell cancer
* MDB - See Medulloblastoma
* MDC1A - See Congenital muscular dystrophy type 1A
* MdDS - See Mal de debarquement
* MDEBS - See Epidermolysa bullosa simplex with muscular dystrophy
* MD-EBS - See Epidermolysa bullosa simplex with muscular dystrophy
* MDK - See Mesomelic dysplasia Kantaputra type
* MDLS - See Miller-Dieker syndrome
* MDM - See Meleda disease
* MDP syndrome
* MDR3 deficiency - See Cholestasis, progressive familial intrahepatic 3
* MDRS1 - See Rigid spine syndrome
* MDS - See Myelodysplastic syndromes
* Meacham Winn Culler syndrome
* Meadows' syndrome - See Peripartum cardiomyopathy
* Measles
* MEB - See Muscle eye brain disease
* Meckel Gruber syndrome - See Meckel syndrome
* Meckel syndrome
* Meckel syndrome type 2
* Meckel syndrome type 3
* Meconium aspiration syndrome
* MECP2 duplication syndrome - See Lubs X-linked mental retardation syndrome
* MED - See Multiple epiphyseal dysplasia
* MED23
* Medeira-Dennis-Donnai syndrome
* Medial confluence of the breasts - See Symmastia
* Medial Medullary Syndrome
* Median cleft of upper lip with polyps of facial skin and nasal mucosa
* Median cleft upper lip, mental retardation and pugilistic facies - See Pallister W syndrome
* Median facial cleft syndrome - See Frontonasal dysplasia
* Median fissure of nose - See Bifid nose
* Median nodule of the upper lip
* Mediastinal endodermal sinus tumors
* Mediastinal fibrosis - See Fibrosing mediastinitis
* Mediastinal fibrosis, familial - See Multifocal fibrosclerosis
* Mediastinal gray zone lymphoma - See Gray zone lymphoma
* Medication-induced gigantomastia (subtype) - See Gigantomastia
* MED-IDDM syndrome - See Epiphyseal dysplasia multiple with early-onset diabetes mellitus
* Mediterranean anemia - See Beta-thalassemia
* Mediterranean Kaposi sarcoma - See Classic Kaposi sarcoma
* Medium and short chain 3-hydroxyacyl-CoA dehydrogenase deficiency - See 3-alpha hydroxyacyl-CoA dehydrogenase deficiency
* Medium chain acyl CoA dehydrogenase deficiency - See Medium-chain acyl-coenzyme A dehydrogenase deficiency
* Medium-chain 3-ketoacyl-coa thiolase deficiency
* Medium-chain acyl-CoA dehydrogenase deficiency - See Medium-chain acyl-coenzyme A dehydrogenase deficiency
* Medium-chain acyl-coenzyme A dehydrogenase deficiency
* Medrano Roldan syndrome
* Medullary Cystic Disease - See Medullary cystic kidney disease
* Medullary cystic kidney disease
* Medullary cystic kidney disease 1
* Medullary cystic kidney disease 2
* Medullary cystic kidney disease 2, autosomal dominant - See Medullary cystic kidney disease 2
* Medullary cystic kidney disease, autosomal dominant - See Medullary cystic kidney disease 1
* Medullary paraganglioma - See Pheochromocytoma
* Medullary sponge kidney
* Medullary thyroid cancer (MTC) - See Thyroid cancer, medullary
* Medulloblastoma
* Medulloblastoma, childhood
* Meesman dystrophy - See Meesmann corneal dystrophy
* Meesmann corneal dystrophy
* Meesmann corneal epithelial dystrophy - See Meesmann corneal dystrophy
* Mega cisterna magna (type of DW complex) - See Dandy-Walker complex
* Megacystis microcolon intestinal hypoperistalsis syndrome
* Megaduodenum and/or megacystis
* Megaepiphyseal dwarfism
* Megalencephalic leukoencephalopathy with subcortical cysts
* Megalencephaly and perisylvian polymicrogyria with postaxial polydactyly and hydrocephalus - See Megalencephaly, polymicrogyria, and hydrocephalus (MPPH) syndrome
* Megalencephaly cutis marmorata telangiectatica congenita - See Macrocephaly-capillary malformation
* Megalencephaly in infancy accompanied by progressive spasticity and dementia - See Alexander disease
* Megalencephaly, polymicrogyria, and hydrocephalus (MPPH) syndrome
* Megalencephaly-cystic leukodystrophy - See Megalencephalic leukoencephalopathy with subcortical cysts
* Megaloblastic anemia 1 - See Imerslund-Grasbeck syndrome
* Megaloblastic anemia due to dihydrofolate reductase deficiency
* Megaloblastic anemia thiamine-responsive with diabetes mellitus and sensorineural deafness - See Thiamine responsive megaloblastic anemia syndrome
* Megalocephaly cutis marmorata telangiectatica congenita - See Macrocephaly-capillary malformation
* Megalocornea - spherophakia - secondary glaucoma
* Megalocornea mental retardation syndrome
* Megalocornea, multiple skeletal anomalies, and developmental delay - See Frank Ter Haar syndrome
* Megalocytic interstitial nephritis
* Megalodactylism of the foot - See Macrodactyly of the foot
* Megalodactylism of the hand - See Macrodactyly of the hand
* Megalodactyly of the foot - See Macrodactyly of the foot
* Megalodactyly of the hand - See Macrodactyly of the hand
* Megarbane Jalkh syndrome
* Megarbane syndrome
* Mehes syndrome
* MEHMO - See Mental retardation, epileptic seizures, hypogonadism and hypogenitalism, microcephaly, and obesity
* MEHMO syndrome - See Mental retardation, epileptic seizures, hypogonadism and hypogenitalism, microcephaly, and obesity
* Mehta Lewis Patton syndrome
* Meier Blumberg Imahorn syndrome
* Meier-Gorlin syndrome
* Meige disease - See Hereditary lymphedema type II
* Meige lymphedema - See Hereditary lymphedema type II
* Meige syndrome
* Meigel disease
* Meige's syndrome - See Meige syndrome
* Meinecke syndrome
* Melanocytic lesions of CNS
* Melanoma and neural system tumor syndrome - See Melanoma astrocytoma syndrome
* Melanoma astrocytoma syndrome
* Melanoma of the gastrointestinal tract - See Primary gastrointestinal melanoma
* Melanoma of the GI tract - See Primary gastrointestinal melanoma
* Melanoma of the Uvea - See Intraocular melanoma
* Melanoma, familial
* Melanoma-associated retinopathy
* Melanosis, neurocutaneous - See Neurocutaneous melanosis
* Melanotic schwannoma (histologic variant) - See Schwannoma
* MELAS - See Mitochondrial encephalomyopathy lactic acidosis and stroke-like episodes
* MELAS syndrome - See Mitochondrial encephalomyopathy lactic acidosis and stroke-like episodes
* Meleda disease
* MELF - See Lafora disease
* Melhem Fahl syndrome
* Meliodosis
* Melkersson syndrome - See Melkersson-Rosenthal syndrome
* Melkersson-Rosenthal syndrome
* Melnick-Fraser syndrome - See Branchiootorenal syndrome
* Melnick-Needles osteodysplasty - See Melnick-Needles syndrome
* Melnick-Needles syndrome
* Melorheostosis
* Meltzer syndrome - See Cryoglobulinemia, familial mixed
* Membranoproliferative glomerulonephritis
* Membranoproliferative glomerulonephritis type 2 - See Dense deposit disease
* Membranoproliferative glomerulonephritis type II - See Dense deposit disease
* Membranous glomerulonephritis - See Membranous nephropathy
* Membranous GN - See Membranous nephropathy
* Membranous nephropathy
* Memory loss, extreme sexual behavior, placidity, and visual distractibility - See Kluver Bucy syndrome
* MEN 1 - See Multiple endocrine neoplasia type 1
* MEN 2A - See Multiple endocrine neoplasia type 2A
* MEN 2B - See Multiple endocrine neoplasia type 2B
* MEN2 - See Multiple endocrine neoplasia type 2
* MEN-2A syndrome - See Multiple endocrine neoplasia type 2A
* Mende Syndrome - See Waardenburg syndrome
* Mendelian susceptibility to mycobacterial infections due to IL12 deficiency - See IL12RB1 deficiency
* Mendenhall Syndrome - See Rabson-Mendenhall syndrome
* Menetrier disease
* Mengel-Konigsmark syndrome - See Conductive deafness with malformed external ear
*   Meniere disease - See Ménière's disease
*   Meniere's disease - See Ménière's disease
*   Ménière's disease
* Meningeal capillary angiomatosis - See Sturge-Weber syndrome
* Meningeal syphilis - See Syphilitic aseptic meningitis
* Meningioma
*   Meningioma 1 gene - See MN1
* Meningioma, spinal
* Meningioma, spine - See Meningioma, spinal
* Meningitis, bacterial - See Bacterial meningitis
* Meningitis, neonatal - See Neonatal meningitis
* Meningitis, syphilitic - See Syphilitic aseptic meningitis
* Meningocele
* Meningococcal disease - See Neisseria meningitidis infection
* Meningococcal infection
* Meningococcemia
* Meningoencephalitis caused by Naegleria fowleri - See Primary amebic meningoencephalitis
* Meningoencephalocele
* Meningoencephalocele, arthrogryposis and hypoplastic thumbs - See Podder-Tolmie syndrome
* Meningomyelocele - See Myelomeningocele
* Menkea syndrome - See Menkes disease
* Menkes disease
* Menkes syndrome - See Menkes disease
* Mental deficiency, choroideremia, acrokeratosis verruciformis,anhidrosis, skeletal deformity - See Van Den Bosch syndrome
* Mental deficiency, epilepsy and endocrine disorders - See Borjeson-Forssman-Lehmann syndrome
* Mental deficiency-epilepsy-endocrine disorders
* Mental retardation , X-linked with seizures, short stature and midface hypoplasia - See X-linked creatine deficiency
* Mental retardation , X-linked, with creatine transport deficiency - See X-linked creatine deficiency
* Mental retardation and multiple nevi - See Upton Young syndrome
* Mental retardation and muscular atrophy - See Allan-Herndon-Dudley syndrome
* Mental retardation anophthalmia craniosynostosis
* Mental Retardation Aphasia Shuffling Gait Adducted Thumbs (MASA) - See Spastic paraplegia 1
* Mental retardation arachnodactyly hypotonia telangiectasia
* Mental retardation athetosis microphthalmia
* Mental retardation Buenos Aires type - See Intellectual deficit Buenos-Aires type
* Mental retardation cataracts calcified pinnae myopathy
* Mental retardation coloboma slimness
* Mental retardation dysmorphism hypogonadism diabetes
* Mental retardation epilepsy
* Mental retardation epilepsy bulbous nose
* Mental retardation gynecomastia obesity X-linked
* Mental retardation hip luxation G6PD variant
* Mental retardation hypocupremia hypobetalipoproteinemia
* Mental retardation hypoplastic corpus callosum preauricular tag - See Agenesis of the corpus callosum
* Mental retardation hypotonia skin hyperpigmentation
* Mental retardation macrocephaly coarse facies hypotonia
* Mental retardation microcephaly epilepsy and ataxia syndrome - See Christianson syndrome
* Mental retardation microcephaly phalangeal facial
* Mental retardation microcephaly unusual facies
* Mental retardation Mietens Weber type
* Mental retardation progressive spasticity
* Mental retardation psychosis macroorchidism - See PPM-X syndrome
* Mental retardation short stature deafness genital
* Mental retardation short stature hypertelorism - See Intellectual deficit - short stature - hypertelorism
* Mental retardation short stature microcephaly eye
* Mental retardation skeletal dysplasia abducens palsy
* Mental retardation Smith Fineman Myers type
* Mental retardation spasticity ectrodactyly
* Mental retardation syndrome with preaxial brachydactyly, hyperphalangism, deafness and orodental anomalies - See Temtamy preaxial brachydactyly syndrome
* Mental retardation syndrome, Belgian type
* Mental retardation syndrome, Mietens Weber type - See Mental retardation Mietens Weber type
* Mental retardation unusual facies Ampola type - See Ampola syndrome
* Mental retardation unusual facies Davis Lafer type - See Davis Lafer syndrome
* Mental retardation with hypotonia and facial dysmorphism - See Birk Barel mental retardation dysmorphism syndrome
* Mental retardation with optic atrophy, deafness, and seizures - See X-linked mental retardation Gustavson type
* Mental retardation with osteocartilaginous abnormalities - See Coffin-Lowry syndrome
* Mental retardation with patellar hypoplasia and luxation - See Patella hypoplasia mental retardation
* Mental retardation with psychosis, pyramidal signs, and macroorchidism - See PPM-X syndrome
* Mental retardation with spastic paraplegia and palmoplantar hyperkeratosis - See Fitzsimmons syndrome
* Mental retardation Wolff type
* Mental retardation x-linked 60 (formerly) - See Mental retardation x-linked with cerebellar hypoplasia and distinctive facial appearance
* Mental retardation X-linked Abidi type - See Abidi X-linked mental retardation syndrome
* Mental retardation X-linked Atkin type - See Atkin syndrome
* Mental retardation X-linked borderline Maoa metabolism anomaly
* Mental retardation X-linked dysmorphism
* Mental retardation X-linked severe Gustavson type - See X-linked mental retardation Gustavson type
* Mental retardation X-linked Shashi type - See Mental retardation X-linked syndromic 11
* Mental retardation X-linked Siderius type - See Siderius X-linked mental retardation syndrome
* Mental retardation X-linked syndromic 11
* Mental retardation X-linked syndromic 5 - See Dandy-Walker malformation with mental retardation basal ganglia disease and seizures
* Mental retardation X-linked syndromic 7
* Mental retardation x-linked syndromic Christianson type - See Christianson syndrome
* Mental retardation x-linked with cerebellar hypoplasia and distinctive facial appearance
* Mental retardation X-linked with Dandy-Walker malformation basal ganglia disease and seizures - See Dandy-Walker malformation with mental retardation basal ganglia disease and seizures
* Mental retardation X-linked, Atkin type - See Mental retardation, X-linked, nonspecific
* Mental retardation X-linked, South African type
* Mental retardation X-linked, Tranebjaerg type seizures and psoriasis - See Tranebjaerg Svejgaard syndrome
* Mental retardation, X-linked Hyde-Forster type - See Plagiocephaly and X-linked mental retardation
* Mental retardation, absence of eyebrows and eyelashes, progressive spastic quadriplegia, microcephaly, glaucoma, and small, beaked nose - See Pseudoprogeria syndrome
* Mental retardation, autosomal dominant 20 - See 5q14.3 microdeletion syndrome
* Mental retardation, cleft palate, eventration of diaphragm, congenital heart defect, glaucoma, craniosynostosis and growth failure - See Lowry Maclean syndrome
* Mental retardation, coarse faces, microcephaly, moderate to severe mental retardation, epilepsy and skeletal - See Battaglia Neri syndrome
* Mental retardation, epilepsy, palpebral conjunctival telangiectasias and IgA deficiency - See Epilepsy telangiectasia
* Mental retardation, epilepsy, short stature and skeletal dysplasia - See Gurrieri syndrome
* Mental retardation, epileptic seizures, hypogonadism and hypogenitalism, microcephaly, and obesity
* Mental retardation, hypotonicity, incontinence, muscle atrophy, and inability to walk or speak - See Passos-Bueno syndrome
* Mental retardation, keratoconus, febrile seizures, and sinoatrial block
* Mental retardation, large head, imperforate anus, congenital hypotonia, and partial agenesis of corpus callosum - See FG syndrome
* Mental retardation, macrocephaly, short stature and craniofacial dysmorphism
* Mental retardation, malformations, chromosome breakage, and development of T-cell leukemia - See N syndrome
* Mental retardation, microcephaly, and distinct facial features with or without Hirschsprung disease - See Mowat-Wilson syndrome
* Mental retardation, microcephaly, weight deficiency, unusual facies, clinodactyly, bone hypoplasia, and cleft palate - See Weaver Williams syndrome
* Mental retardation, obesity, hypogonadism, and tapering fingers - See Mental retardation X-linked syndromic 7
* Mental retardation, peculiar facies, kyphoscoliosis, diastasis recti, cryptorchidism, and congenital heart defect - See McDonough syndrome
* Mental retardation, plagiocephaly, brachycephaly, prominent forehead, and coarse facial features - See Plagiocephaly and X-linked mental retardation
* Mental retardation, postaxial polydactyly, phalangeal hypoplasia, 2-3 toe syndactyly, unusual face, uncombable hair - See Kozlowski-Krajewska syndrome
* Mental retardation, spasticity and transverse limb defects - See Mental retardation spasticity ectrodactyly
* Mental retardation, Stocco dos Santos type - See Stocco dos Santos syndrome
* Mental retardation, tall stature, obesity, macrocephaly and typical facial features - See Clark-Baraitser syndrome
* Mental retardation, truncal obesity, retinal dystrophy and micropenis - See MORM syndrome
* Mental retardation, unusual facies, and intrauterine growth retardation - See Pitt syndrome
* Mental retardation, wide mouth, distinctive facial features, and intermittent hyperventilation followed by apnea - See Pitt-Hopkins syndrome
* Mental retardation, X-linked 14
* Mental retardation, X-linked nonspecific, type 1 - See Mental retardation, X-linked, nonspecific
* Mental retardation, X-linked nonspecific, type 14 - See Mental retardation, X-linked 14
* Mental retardation, X-linked Renpenning type - See Renpenning syndrome 1
* Mental retardation, X-linked with dysmorphism and cerebral atrophy - See Prieto X-linked mental retardation syndrome
* Mental retardation, X-linked, 21 - See Mental retardation, X-linked, nonspecific
* Mental retardation, X-linked, Hyde-Forster type - See Hyde Forster Mccarthy Berry syndrome
* Mental retardation, X-linked, Lubs type - See Lubs X-linked mental retardation syndrome
* Mental retardation, X-linked, nonspecific
* Mental retardation, X-linked, syndromic 1 - See Partington X-linked mental retardation syndrome
* Mental retardation, X-linked, syndromic 13 - See PPM-X syndrome
* Mental retardation, X-linked, syndromic 2 - See Prieto X-linked mental retardation syndrome
* Mental retardation, X-linked, syndromic 4 - See Miles-Carpenter x-linked mental retardation syndrome
* Mental retardation, X-linked, syndromic 6 - See Wilson-Turner X-linked mental retardation syndrome
* Mental retardation, X-linked, syndromic 8 - See Renpenning syndrome 1
* Mental retardation, X-linked, with congenital contractures and low fingertip arches - See Miles-Carpenter x-linked mental retardation syndrome
* Mental retardation, X-linked, with craniofacial dysmorphism - See Hyde Forster Mccarthy Berry syndrome
* Mental retardation, X-linked, with dystonic movements, ataxia, and seizures - See Partington X-linked mental retardation syndrome
* Mental retardation, x-linked, with growth retardation, deafness, and microgenitalism - See Mental retardation-hypotonic facies syndrome X-linked, 1
* Mental retardation, X-linked, with gynecomastia and obesity - See Wilson-Turner X-linked mental retardation syndrome
* Mental retardation, X-linked, with marfanoid habitus - See Lujan Fryns syndrome
* Mental retardation-dystonic movements-ataxia-seizures syndrome - See Partington X-linked mental retardation syndrome
* Mental retardation-hypotonic facies syndrome X-linked, 1
* Mental retardation-polydactyly-uncombable hair
* Mental Retradation, X-linked with Growth Delay, Deafness, Microgenitalism - See Juberg Marsidi syndrome
* Menzel type OPCA - See Spinocerebellar ataxia 1
* Meralgia paraesthetica familial (type) - See Meralgia paresthetica
* Meralgia paresthetica
* Mercury poisoning
* Mercury toxicity - See Mercury poisoning
* Merkel cell cancer - See Merkel cell carcinoma
* Merkel cell carcinoma
* Merkle tumors - See Merkel cell carcinoma
* Merlob Grunebaum Reisner syndrome
* Mermaid malformation - See Sirenomelia
* Mermaid syndrome - See Sirenomelia
* Merosin-deficient congenital muscular dystrophy - See Congenital muscular dystrophy type 1A
* Merosin-negative congenital muscular dystrophy - See Congenital muscular dystrophy type 1A
* MERRF - See Myoclonus with epilepsy with ragged red fibers
* Merrf syndrome - See Myoclonus with epilepsy with ragged red fibers
* Merten-Singleton syndrome - See Singleton Merten syndrome
* MES - See Malignant eccrine spiradenoma
* Mesangial proliferative glomerulonephritis
* Mesangial proliferative GN - See Mesangial proliferative glomerulonephritis
* Mesangial sclerosis, diffuse - See Diffuse mesangial sclerosis
* Mesangiocapillary glomerulonephritis - See Membranoproliferative glomerulonephritis
* Mesangiocapillary glomerulonephritis type 2 - See Dense deposit disease
* Mesangioproliferative glomerulopathy
* Mesenteric artery ischemia
* Mesenteric fibromatosis - See Sclerosing mesenteritis
* Mesenteric lipodystrophy - See Sclerosing mesenteritis
* Mesenteric lipogranuloma - See Sclerosing mesenteritis
* Mesenteric panniculitis - See Sclerosing mesenteritis
* Mesenteric vascular disease - See Mesenteric artery ischemia
* Mesiodens cataract syndrome - See Nance-Horan syndrome
* Mesodermal dysmorphodystrophy congenital - See Weill-Marchesani syndrome
* Mesoectodermal dysplasia - See Ellis-Van Creveld syndrome
* Mesomelia
* Mesomelia of the upper limbs, absent nails, clubfeet, and mental retardation - See Ulna hypoplasia with mental retardation
* Mesomelia synostoses - See Mesomelia-synostoses syndrome
* Mesomelia, radial hypoplasia bifid thumb unusual facies - See Brunoni syndrome
* Mesomelia-synostoses syndrome
* Mesomelic dwarfism Campailla-Martinelli type - See Acromesomelic dysplasia Campailla Martinelli type
* Mesomelic dwarfism cleft palate camptodactyly
* Mesomelic dwarfism Nievergelt type - See Nievergelt syndrome
* Mesomelic dwarfism of hypoplastic tibia and radius type
* Mesomelic dwarfism of hypoplastic ulna and fibula type - See Ulna and fibula, hypoplasia of
* Mesomelic dwarfism of the hypoplastic ulna, fibula and mandible type - See Langer mesomelic dysplasia
* Mesomelic dwarfism, skeletal abnormalities, and ectodermal dysplasia - See Brunoni syndrome
* Mesomelic dysplasia Kantaputra type
* Mesomelic dysplasia Reinhardt-Pfeiffer type - See Ulna and fibula, hypoplasia of
* Mesomelic dysplasia Savarirayan type
* Mesomelic dysplasia skin dimples
* Mesomelic dysplasia Thai type - See Mesomelic dysplasia Kantaputra type
* Mesomelic dysplasia with absent fibulas and triangular tibias - See Mesomelic dysplasia Savarirayan type
* Mesomelic dysplasia with ankle carpal and tarsal synostosis - See Mesomelic dysplasia Kantaputra type
* Mesomelic limb shortening and bowing - See Mesomelic dwarfism cleft palate camptodactyly
* Mesomelic shortening and hereditary nephritis - See Dyschondrosteosis nephritis
* Mesothelioma, malignant - See Malignant mesothelioma
* MesPGN - See Mesangioproliferative glomerulopathy
* Metabolic myopathy associated with chronic lactic acidemia, growth failure, and nerve deafness - See Mitochondrial myopathy with lactic acidosis
* Metabolic syndrome X - See Abdominal obesity metabolic syndrome
* Metacarpals 4 and 5 fusion
* Metachondromatosis
* Metachromatic leukodystrophy
* Metachromatic leukodystrophy due to cerebroside sulfatase activator deficiency - See Metachromatic leukodystrophy due to saposin B deficiency
* Metachromatic leukodystrophy due to saposin B deficiency
* Metachromatic leukoencephalopathy - See Metachromatic leukodystrophy
* Metageria - See Acrogeria, Gottron type
* Metagonimiasis
* Metagonimus yokogawai infection - See Metagonimiasis
* Metaphyseal acroscyphodysplasia
* Metaphyseal anadysplasia
* Metaphyseal and epiphyseal dysplasia with unusual facies and cataract - See Kozlowski Rafinski Klicharska syndrome
* Metaphyseal chondrodysplasia McKusick type - See Cartilage-hair hypoplasia
* Metaphyseal chondrodysplasia Murk Jansen type - See Jansen type metaphyseal chondrodysplasia
* Metaphyseal chondrodysplasia Schmid type
* Metaphyseal chondrodysplasia Spahr type
* Metaphyseal chondrodysplasia with cone-shaped epiphyses and alopecia - See Trichoscyphodysplasia
* Metaphyseal chondrodysplasia with cone-shaped epiphyses, normal hair, and normal hands
* Metaphyseal chondrodysplasia with ectodermal dysplasia - See Trichoscyphodysplasia
* Metaphyseal chondrodysplasia, others
* Metaphyseal chondroplasia Rosenberg type - See Ulna metaphyseal dysplasia syndrome
* Metaphyseal dysostosis mental retardation conductive deafness
* Metaphyseal dysostosis, conductive hearing loss and mental retardation - See Metaphyseal dysostosis mental retardation conductive deafness
* Metaphyseal dysplasia - See Pyle disease
* Metaphyseal dysplasia hypertelorism hypospadias - See Say Carpenter syndrome
* Metaphyseal dysplasia maxillary hypoplasia brachydactyly
* Metaphyseal dysplasia Pyle type - See Pyle disease
* Metaphyseal dysplasia without hypotrichosis
* Metaphyseal modeling abnormality, skin lesions, and Spastic paraplegia - See Roy Maroteaux Kremp syndrome
* Metaphyseal undermodeling, spondylar dysplasia, and overgrowth
* Metaplastic breast cancer - See Metaplastic carcinoma of the breast
* Metaplastic carcinoma of the breast
* Metastatic dermatofibrosarcoma protuberans (subtype) - See Dermatofibrosarcoma protuberans
* Metastatic insulinoma
* Metastatic squamous neck cancer with occult primary
*   Metatarsus adductus
* Metatropic dwarfism - See Metatropic dysplasia
* Metatropic dysplasia
* Metatropic dysplasia, nonlethal dominant - See Metatropic dysplasia
* METCDS - See Metachondromatosis
* Methemoglobinemia due to deficiency of methemoglobin reductase - See NADH cytochrome B5 reductase deficiency
* Methimazole antenatal infection
* Methionine adenosyltransferase deficiency
* Methionine synthase deficiency - See Arakawa's syndrome 2
* Methyl mercury antenatal infection
* Methylcobalamin deficiency cbl G type
* Methylcobalamin deficiency, cbl E complementation type
* Methylcrotonylglycinuria type 2 - See 3 alpha methylcrotonyl-CoA carboxylase 2 deficiency
* Methylenetetrahydro-folate reductase deficiency - See Homocysteinemia due to MTHFR deficiency
*   Methylenetetrahydrofolate reductase mutation - See MTHFR gene mutation
* Methylmalonic acidemia
* Methylmalonic acidemia and homocystinemia - See Methylmalonic acidemia with homocystinuria
* Methylmalonic acidemia and homocystinuria cblc - See Methylmalonic acidemia and homocystinuria cblC type
* Methylmalonic acidemia and homocystinuria cblC type
* Methylmalonic acidemia cblA type - See Methylmalonic aciduria cblA type
* Methylmalonic acidemia cblB type - See Methylmalonic aciduria cblB type
* Methylmalonic acidemia with homocystinuria
* Methylmalonic aciduria and homocystinuria cblc - See Methylmalonic acidemia and homocystinuria cblC type
* Methylmalonic aciduria cblA type
* Methylmalonic aciduria cblB type
* Methylmalonic aciduria microcephaly cataract
* Methylmalonic aciduria with homocystinuria cbl f
* Methylmalonic aciduria, vitamin b12-responsive, due to defect in synthesis of adenosylcobalamin, cbla complementation type - See Methylmalonic aciduria cblA type
* Methylmalonicacidemia with homocystinuria cbl d
* Methylmalonyl-Coenzyme A mutase deficiency
* Mevalonate kinase deficiency - See Mevalonic aciduria
* Mevalonic aciduria
* Mevalonicaciduria - See Mevalonic aciduria
* Meyer-Schwickerath's syndrome - See Fraser syndrome
* MFD Toriello type - See Branchial arch syndrome X-linked
* MFD1 - See Treacher Collins syndrome
* MFT1 - See Multiple familial trichoepithelioma 1
* MFT2 - See Multiple familial trichoepithelioma 2
* MGA 5 - See 3 methylglutaconic aciduria type V
* MGA type I - See 3 methylglutaconic aciduria type I
* MGA type II - See Barth syndrome
* MGA type III - See 3-methylglutaconic aciduria type III
* MGA V - See 3 methylglutaconic aciduria type V
* MGA3 - See 3-methylglutaconic aciduria type III
* MGN - See Membranous nephropathy
* MGS - See Mungan syndrome
* MGUS - See Monoclonal gammopathy of undetermined significance
* MH - See Malignant hyperthermia
* MHAC - See Microhydranencephaly
* MHAM - See Cowden syndrome
* MHBD deficiency - See 2-methyl-3-hydroxybutyric aciduria
* MHC class 1 deficiency
* MHP1 - See Familial hemiplegic migraine type 1
* MHP2 - See Familial hemiplegic migraine type 2
* MHP3 - See Familial hemiplegic migraine type 3
* MHS - See Malignant hyperthermia susceptibility type 1
* MHS1 - See Malignant hyperthermia susceptibility type 1
* MHS2 - See Malignant hyperthermia susceptibility type 2
* MHS3 - See Malignant hyperthermia susceptibility type 3
* MHS4 - See Malignant hyperthermia susceptibility type 4
* MHS5 - See Malignant hyperthermia susceptibility type 5
* MHS6 - See Malignant hyperthermia susceptibility type 6
* Michelin tire baby syndrome
* Michels Caskey syndrome
* Michels syndrome
* Micro syndrome - See Warburg micro syndrome
* Microangiopathic hemolytic anemia - See Thrombotic thrombocytopenic purpura, congenital
* Microangiopathic hemolytic anemia, congenital - See Thrombotic thrombocytopenic purpura, congenital
* Microbrachycephaly ptosis cleft lip
* Microcephalic osteodysplastic primordial dwarfism type 1
* Microcephalic osteodysplastic primordial dwarfism type 2
* Microcephalic osteodysplastic primordial dwarfism types 1 and 3 - See Microcephalic osteodysplastic primordial dwarfism type 1
* Microcephalic osteodysplastic primordial dwarfism with tooth abnormalities - See Microcephalic osteodysplastic primordial dwarfism type 2
* Microcephalic primordial dwarfism and cataracts - See Microcephalic primordial dwarfism Toriello type
* Microcephalic primordial dwarfism Toriello type
* Microcephaly
* Microcephaly - brain defect - spasticity - hypernatremia - See Microcephaly brain defect spasticity hypernatremia
* Microcephaly - seizures - developmental delay - See Microcephaly, seizures, and developmental delay
* Microcephaly autosomal dominant
* Microcephaly brachydactyly kyphoscoliosis - See Viljoen Kallis Voges syndrome
* Microcephaly brain defect spasticity hypernatremia
* Microcephaly cervical spine fusion anomalies
* Microcephaly chorioretinopathy recessive form
* Microcephaly cleft palate autosomal dominant - See Halal syndrome
* Microcephaly deafness syndrome
* Microcephaly glomerulonephritis Marfanoid habitus
* Microcephaly hypergonadotropic hypogonadism short stature
* Microcephaly hypogammaglobulinemia abnormal immunity - See Say Barber Miller syndrome
* Microcephaly immunodeficiency lymphoreticuloma - See Nijmegen breakage syndrome
* Microcephaly intracranial calcification - See Baraitser Brett Piesowicz syndrome
* Microcephaly lymphedema chorioretinal dysplasia - See Lymphedema, microcephaly and chorioretinopathy syndrome
* Microcephaly microcornea syndrome Seemanova type
* Microcephaly micropenis convulsions
* Microcephaly micropenis seizures - See Microcephaly micropenis convulsions
* Microcephaly microphthalmia ectrodactyly of lower limbs and prognathism - See Microphthalmia syndromic 8
* Microcephaly microphthalmos blindness
* Microcephaly nephrosis syndrome - See Microcephaly, hiatal hernia and nephrotic syndrome
* Microcephaly nonsyndromal
* Microcephaly pontocerebellar hypoplasia dyskinesia
* Microcephaly seizures genital hypoplasia - See Microcephaly micropenis convulsions
* Microcephaly seizures mental retardation heart disorders
* Microcephaly sparse hair mental retardation seizures
* Microcephaly with autosomal dominant inheritance - See Microcephaly autosomal dominant
* Microcephaly with cardiomyopathy - See Microcephaly-cardiomyopathy
* Microcephaly with chemotactic defect and transient hypogammaglobulinemia - See Say Barber Miller syndrome
* Microcephaly with chorioretinopathy, autosomal dominant form
* Microcephaly with normal intelligence immunodeficiency and lymphoreticular malignancies - See Nijmegen breakage syndrome
* Microcephaly with spastic diplegia - See Paine syndrome
* Microcephaly with spastic quadriplegia
* Microcephaly, Amish type - See Amish lethal microcephaly
* Microcephaly, central nervous system dysfunction, minor craniofacial and limb anomalies, and variable growth deficiency - See Hersh Podruch Weisskopk syndrome
* Microcephaly, congenital heart disease, lung segmentation defects and unilateral renal agenesis - See Ellis Yale Winter syndrome
* Microcephaly, corpus callosum dysgenesis and cleft lip-palate
* Microcephaly, facial clefting, and preaxial polydactyly - See Microcephaly, corpus callosum dysgenesis and cleft lip-palate
* Microcephaly, hiatal hernia and nephrotic syndrome
* Microcephaly, holoprosencephaly, and intrauterine growth retardation
* Microcephaly, IUGR, Hypertelorism, Ptosis, iris coloboma, hooked nose, external ear dysplasia, psychomotor retardation - See Wolf-Hirschhorn syndrome
* Microcephaly, microcornea, congenital cataract, mental retardation, optic atrophy and hypogenitalism - See Warburg micro syndrome
* Microcephaly, mild mental retardation, short stature, and skeletal anomalies - See Microcephaly cervical spine fusion anomalies
* Microcephaly, postnatal progressive, with seizures and brain atrophy
* Microcephaly, primary autosomal recessive
* Microcephaly, schizencephaly, decorticated disturbance of the neurological function, congenital optic atrophy and nystagmus - See Silengo Lerone Pelizza syndrome
* Microcephaly, seizures, and developmental delay
* Microcephaly, seizures, mental retardation, congenital heart disease, and skeletal abnormalities - See Microcephaly seizures mental retardation heart disorders
* Microcephaly, short stature, brachydactyly type D, flattened occiput, low-set large ears, prominent nose, kyphoscoliosis and intellectual disability - See Viljoen Kallis Voges syndrome
* Microcephaly, short stature, slow growth, beak nose, micrognathia, skin dyspigmentation and forearm and thumb dysplasia - See Milner Khallouf Gibson syndrome
* Microcephaly-albinism-digital anomalies syndrome
* Microcephaly-cardiomyopathy
* Microcephaly-cardiomyopathy syndrome - See Microcephaly-cardiomyopathy
* Microcephaly-microcornea syndrome, Seemanova type - See Microcephaly microcornea syndrome Seemanova type
* Microcephaly-oculo-digito-esophageal-duodenal syndrome - See Feingold syndrome
* Microcoria - congenital nephrosis - See Pierson syndrome
* Microcoria - congenital nephrotic syndrome - See Pierson syndrome
* Microcoria, congenital
* Microcornea posterior megalolenticonus persistent fetal vasculature coloboma
* Microcornea cataract syndrome - See Cataract microcornea syndrome
* Microcornea corectopia macular hypoplasia
* Microcornea, glaucoma, and absent frontal sinuses
* Microcystic adnexal carcinoma
* Microcystic dystrophy of the cornea - See Epithelial basement membrane corneal dystrophy
* Microdeletion 15q11.2
* Microdeletion 15q13.3 syndrome - See 15q13.3 microdeletion syndrome
* Microdeletion 16p11.2 - See 16p11.2 deletion syndrome
* Microdeletion 17q21.31 syndrome - See Koolen de Vries syndrome
* Microdontia hypodontia short stature
* Microdontia, hypodontia, short bulbous roots and root canals with strabismus, short stature, and borderline mentality - See Microdontia hypodontia short stature
* Microduplication 15q13.3 syndrome - See 15q13.3 microduplication syndrome
* Microduplication 3q29 syndrome - See Chromosome 3q29 microduplication syndrome
* Microencephaly
* Microgastria limb reduction defect
* Microgastria-limb reduction defects association - See Microgastria limb reduction defect
* Microhydranencephaly
* Micromelic bone dysplasia with cloverleaf skull
* Micromelic dwarfism with cone epiphyses, metaphyseal dysplasia and vertebral segmentation defects - See Spondyloepimetaphyseal dysplasia micromelic
* Micromelic dwarfism, narrow chest, vertebral and metaphyseal abnormalities and advanced carpotarsal ossification - See Desbuquois syndrome
* Micromelic dysplasia congenita with dislocation of radius - See Omodysplasia 1
* Micropenis - See Penis agenesis
* Microphthalmia and brain atrophy - See Microphthalmia syndromic 10
* Microphthalmia and corectopia - See Microphthalmia, isolated, with corectopia
* Microphthalmia and esophageal atresia syndrome - See Microphthalmia syndromic 3
* Microphthalmia and pituitary anomalies - See Microphthalmia syndromic 6
* Microphthalmia associated with colobomatous cyst
* Microphthalmia cataract
* Microphthalmia cataracts radiculomegaly and septal heart defects - See Oculofaciocardiodental syndrome
* Microphthalmia Dermal Aplasia and Sclerocornea syndrome - See Microphthalmia syndromic 7
* Microphthalmia Lenz type - See Lenz microphthalmia syndrome
* Microphthalmia mental deficiency
* Microphthalmia microtia fetal akinesia
* Microphthalmia or anophthalmos with associated anomalies (formerly) - See Lenz microphthalmia syndrome
* Microphthalmia syndromic 1 - See Lenz microphthalmia syndrome
* Microphthalmia syndromic 10
* Microphthalmia syndromic 2 - See Oculofaciocardiodental syndrome
* Microphthalmia syndromic 3
* Microphthalmia syndromic 4
* Microphthalmia syndromic 5
* Microphthalmia syndromic 6
* Microphthalmia syndromic 7
* Microphthalmia syndromic 8
* Microphthalmia syndromic 9
* Microphthalmia with ankyloblepharon and mental retardation - See Microphthalmia syndromic 4
* Microphthalmia with brain and digit developmental anomalies - See Microphthalmia syndromic 6
* Microphthalmia with facial clefting - See Anophthalmia plus syndrome
* Microphthalmia with linear skin defects - See Microphthalmia syndromic 7
* Microphthalmia with myopia and corectopia - See Microphthalmia, isolated, with corectopia
* Microphthalmia, isolated, with cataract - See Microphthalmia cataract
* Microphthalmia, isolated, with corectopia
* Microphthalmia-microtia-fetal akinesia - See Microphthalmia microtia fetal akinesia
* Microphthalmia-optic nerve dysplasia - See Oculo-cerebral dysplasia
* Microphthalmos bilateral, colobomatous orbital cyst - See Microphthalmia associated with colobomatous cyst
* Microphthalmos severe mental retardation spastic cerebral palsy - See Microphthalmia mental deficiency
* Microphthalmos, microcornea, and sclerocornea with short stature and hair and dental abnormalities - See Rodrigues blindness
* Microphthalmos, microencephaly, mental retardation, agenesis of the corpus callosum, hypospadius, and cryptorchidism - See Duker Weiss Siber syndrome
*   Microscopic colitis, collagenous type - See Collagenous colitis
* Microscopic polyangiitis
* Microsomal triglyceride transfer protein deficiency disease - See Abetalipoproteinemia
* Microsomal-triglyceride transfer protein deficiency - See Abetalipoproteinemia
* Microsomia hemifacial radial defects
* Microspherophakia and/or megalocornea, with ectopia lentis and with or without secondary glaucoma - See Megalocornea - spherophakia - secondary glaucoma
* Microspherophakia with hernia
* Microspherophakia-metaphyseal dysplasia - See Verloes Van Maldergem Marneffe syndrome
* Microsporidiasis - See Microsporidiosis
* Microsporidiosis
* Microtia aortic arch syndrome - See Isotretinoin embryopathy like syndrome
* Microtia eye coloboma and imperforation of the nasolacrimal duct
* Microtia meatal atresia deafness dominant - See Gupta Patton syndrome
* Microtia with meatal atresia and conductive deafness - See Gupta Patton syndrome
* Microtia, absent patellae, micrognathia syndrome - See Meier-Gorlin syndrome
* Microtia, meatal atresia and conductive deafness
* Microtia-Anotia
* Microvillus atrophy, congenital - See Microvillus inclusion disease
* Microvillus inclusion disease
* MIDAS syndrome - See Microphthalmia syndromic 7
* Midbrain stroke syndromes - See Weber syndrome
* MIDD - See Maternally inherited diabetes and deafness
* Middigital hair - See Midphalangeal hair
* Midline cleft of lower lip
* Midline development field defects - See Schisis association
* Midline granulomatosis - See Granulomatosis with polyangiitis (Wegener's)
* Midline lethal granuloma
* Midline malformations, multiple, with limb abnormalities and hypopituitarism - See Dincsoy-Salih-Patel syndrome
* Midphalangeal hair
* Miescher elastoma - See Elastosis perforans serpiginosa
* Mietens-Weber syndrome - See Mental retardation Mietens Weber type
* Mievis Verellen-Dumoulin syndrome - See Short stature syndrome, Brussels type
* Migraine, familial hemiplegic 1, with progressive cerebellar ataxia - See Familial hemiplegic migraine type 1
* Migraine, familial hemiplegic, 2 - See Familial hemiplegic migraine type 2
* Migraine, familial hemiplegic, 3 - See Familial hemiplegic migraine type 3
* Mikaelian syndrome - See Congenital ectodermal dysplasia with hearing loss
* Mikati Najjar Sahli syndrome - See Microcephaly hypergonadotropic hypogonadism short stature
* Mikulicz disease
* Mikulicz's disease - See Mikulicz disease
* Mild androgen insensitivity syndrome - See Androgen insensitivity syndrome, mild
* Mild form of FAP - See Attenuated familial adenomatous polyposis
* Mild growth retardation and developmental delay, microcephaly, and a distinctive facial appearance - See Partington Anderson syndrome
* Mild mental deficiency, short stature, macrocranium, cardiac anomalies, cutis laxa, peculiar facies, wrinkled palms and soles, small vertebral bodies - See Cantu Sanchez-Corona Hernandez syndrome
* Mild short stature, microcephaly, ptosis-blepharophimosis, facial asymmetry, and radioulnar synostosis - See Jorgenson Lenz syndrome
* Miles-Carpenter x-linked mental retardation syndrome
* Miliaria, apocrine - See Fox-Fordyce disease
* Miliary hepatocellular adenomatosis - See Nodular regenerative hyperplasia
* Miller syndrome
* Miller-Dieker lissencephaly syndrome - See Miller-Dieker syndrome
* Miller-Dieker syndrome
* Miller-Fisher syndrome
* Milner Khallouf Gibson syndrome
* Milroy disease
* Milroy's disease - See Milroy disease
* MILS - See Maternally inherited Leigh syndrome
* Minicore myopathy with external ophthalmoplegia
* Minicore myopathy, antenatal onset, with arthrogryposis
* Minicore myopathy, severe classic form - See Rigid spine syndrome
* Minimal change disease
* Minimal change glomerulopathy - See Minimal change disease
* Minimal change nephrotic syndrome - See Minimal change disease
* Minor streblomicrodactyly, familial - See Familial streblodactyly
* Miosis, congenital - See Microcoria, congenital
* Mirhosseini-Holmes-Walton syndrome - See Retinopathy pigmentary mental retardation
* Mirizzi syndrome
* Mirizzi's syndrome - See Mirizzi syndrome
* Mirror hands and feet with nasal defects - See Laurin-Sandrow syndrome
* Mirror polydactyly segmentation and limbs defects
* Mismatch Repair Cancer Syndrome - See Turcot syndrome
* Mismatch Repair Deficiency - See Turcot syndrome
* Missouri type of spondyloepimetaphyseal dysplasia - See Spondyloepimetaphyseal dysplasia Missouri type
* Mitchell disease (formerly) - See Erythromelalgia
* Mitochondrial acetoacetyl-CoA Thiolase deficiency - See Beta ketothiolase deficiency
* Mitochondrial complex deficiency, combined - See Myopathy, mitochondrial progressive, with congenital cataract, hearing loss, and developmental delay
* Mitochondrial complex I deficiency
* Mitochondrial complex II deficiency
* Mitochondrial complex III deficiency
* Mitochondrial complex IV deficiency
* Mitochondrial complex V deficiency
* Mitochondrial cytopathy - See Kearns Sayre syndrome
* Mitochondrial disease with severe hypotonia, lactic acidaemia and hyperammonemia
* Mitochondrial DNA depletion syndrome 6 - See MPV17-related hepatocerebral mitochondrial DNA depletion syndrome
* Mitochondrial dna depletion syndrome, encephalomyopathic form with methylmalonic aciduria, autosomal recessive - See Encephalomyopathy
* Mitochondrial encephalomyopathy aminoacidopathy - See Encephalomyopathy
* Mitochondrial encephalomyopathy lactic acidosis and stroke-like episodes
* Mitochondrial genetic disorders
* Mitochondrial myopathy with diabetes
* Mitochondrial myopathy with lactic acidosis
* Mitochondrial myopathy, lipid type - See Mitochondrial myopathy with diabetes
* Mitochondrial NADH dehydrogenase component of complex I, deficiency of - See Mitochondrial complex I deficiency
* Mitochondrial neurogastrointestinal encephalopathy syndrome
* Mitochondrial respiratory chain complex II deficiency - See Mitochondrial complex II deficiency
* Mitochondrial trifunctional protein deficiency
* Mitral atresia
* Mitral regurgitation, conductive deafness, and fusion of cervical vertebrae and of carpal and tarsal bones
* Mitral regurgitation, familial - See Mitral valve prolapse, familial, X-linked
* Mitral valve prolapse, familial, autosomal dominant
* Mitral valve prolapse, familial, X-linked
* Miura syndrome
* Mixed cell tumors containing both neural ganglionic cells and neural glial cell components - See Ganglioglioma
* Mixed cerebral palsy - See Cerebral palsy
* Mixed connective tissue disease
* Mixed dust pneumoconiosis - See Labrador lung
* Mixed hyperlipemia - See Hyperlipoproteinemia type 5
* Mixed lineage acute leukemia - See Acute biphenotypic leukemia
* Mixed Mullerian tumor - See Malignant mixed Mullerian tumor
* Mixed phenotype acute leukemia - See Acute biphenotypic leukemia
* Mixed sclerosing bone dysplasia and mental retardation - See Sclerosing bone dysplasia mental retardation
* Mixed sclerosing bone dystrophy
* Mixed spasmodic dysphonia (type) - See Spasmodic dysphonia
* Mixed tumor, Mullerian - See Malignant mixed Mullerian tumor
* Miyoshi distal myopathy - See Miyoshi myopathy
* Miyoshi myopathy
* MJD - See Spinocerebellar ataxia 3
* MKKS - See McKusick Kaufman syndrome
* MKS - See Meckel syndrome
* MKS2 - See Meckel syndrome type 2
* MKS3 - See Meckel syndrome type 3
* ML 2 - See I cell disease
* ML 3 A - See Mucolipidosis III alpha/beta
* ML 4 - See Mucolipidosis type 4
* ML disorder type 2 - See I cell disease
* ML1 - See Sialidosis, type II
* ML3 - See Mucolipidosis III alpha/beta
* MLASA - See Sideroblastic anemia and mitochondrial myopathy
* MLC - See Megalencephalic leukoencephalopathy with subcortical cysts
* MLD - See Metachromatic leukodystrophy
* MLRD - See Microgastria limb reduction defect
* MLS syndrome - See Microphthalmia syndromic 7
* MLT - See Multifocal lymphangioendotheliomatosis with thrombocytopenia
* MM - See Miyoshi myopathy
* MMA - See Methylmalonic acidemia
* MMA cbl A type - See Methylmalonic aciduria cblA type
* MMAD - See ACTH-independent macronodular adrenal hyperplasia
* MMDK - See Mesomelic dysplasia Kantaputra type
* MMEP - See Microphthalmia syndromic 8
* MMEP syndrome - See Microphthalmia syndromic 8
* MMF - See Macrophagic myofasciitis
* MMIH syndrome - See Megacystis microcolon intestinal hypoperistalsis syndrome
* MMIHS - See Megacystis microcolon intestinal hypoperistalsis syndrome
* MMMT - See Malignant mixed Mullerian tumor
*   MMND - See Madras motor neuron disease
* MMR Deficiency - See Turcot syndrome
* MMR syndrome - See Megalocornea mental retardation syndrome
* MMRCS - See Turcot syndrome
* MMS - See Medial Medullary Syndrome
* MMT syndrome - See Feingold syndrome
*   MN1
* MNDJ - See Neuropathy, distal hereditary motor, Jerash type
* MNG/CRD/DA - See Daneman Davy Mancer syndrome
* MNGIE - See Mitochondrial neurogastrointestinal encephalopathy syndrome
* MNGIE syndrome - See Mitochondrial neurogastrointestinal encephalopathy syndrome
* MNRI - See Radiation induced meningioma
* MNS - See Melnick-Needles syndrome
* MOBA - See Microphthalmia syndromic 10
* Mobius syndrome - See Moebius syndrome
* Mobius syndrome 2 (formerly) - See Hereditary congenital facial paresis
* MOCOD - See Molybdenum cofactor deficiency
* MODY - See Maturity-onset diabetes of the young
* MODY type 3 - See Maturity-onset diabetes of the young, type 3
* MODY glucokinase-related - See Maturity-onset diabetes of the young, type 2
* MODY hepatocyte nuclear factor-1-alpha related - See Maturity-onset diabetes of the young, type 3
* MODY HNF4A related - See Maturity-onset diabetes of the young, type 1
* MODY insulin promoter factor-1 related - See Maturity-onset diabetes of the young, type 4
* MODY KLF11 related - See Maturity-onset diabetes of the young, type 7
* MODY NEUROD1 related - See Maturity-onset diabetes of the young, type 6
* MODY PAX4 related - See Maturity-onset diabetes of the young, type 9
* MODY type 1 - See Maturity-onset diabetes of the young, type 1
* MODY type 2 - See Maturity-onset diabetes of the young, type 2
* MODY type 4 - See Maturity-onset diabetes of the young, type 4
* MODY type 5 - See Maturity-onset diabetes of the young, type 5
* MODY type 6 - See Maturity-onset diabetes of the young, type 6
* MODY type 7 - See Maturity-onset diabetes of the young, type 7
* MODY type 9 - See Maturity-onset diabetes of the young, type 9
* MODY1 - See Maturity-onset diabetes of the young, type 1
* MODY2 - See Maturity-onset diabetes of the young, type 2
* MODY3 - See Maturity-onset diabetes of the young, type 3
* MODY4 - See Maturity-onset diabetes of the young, type 4
* MODY5 - See Maturity-onset diabetes of the young, type 5
* MODY6 - See Maturity-onset diabetes of the young, type 6
* MODY7 - See Maturity-onset diabetes of the young, type 7
* MODY8 - See Maturity-onset diabetes of the young, type 8
* MODY9 - See Maturity-onset diabetes of the young, type 9
* Moebius axonal neuropathy hypogonadism
* Moebius sequence - See Moebius syndrome
* Moebius sequence, Robin complex, and hypotonia - See Congenital nonprogressive myopathy with Moebius and Robin sequences
* Moebius syndrome
* Moebius syndrome 2 (formerly) - See Hereditary congenital facial paresis
* Moebius syndrome with hypogonadotrophic hypogonadism and progressive peripheral neuropathy axonal and demyelinating type - See Moebius axonal neuropathy hypogonadism
* Moerman Van den berghe Fryns syndrome - See Fryns syndrome
* Moeschler Clarren syndrome - See Microsomia hemifacial radial defects
* Mohr syndrome - See Orofaciodigital syndrome 2
* Mohr-Tranebjaerg syndrome
* Mohr-Wriedt type brachydactyly - See Brachydactyly type A2
* Molar I reinclusion - See Ankylosis of teeth
* Molar pregnancy - See Hydatidiform mole
* Mollaret meningitis
* Mollaret's meningitis - See Mollaret meningitis
* Mollica syndrome - See Dwarfism, mental retardation and eye abnormality
* Mollica-Pavone-Antener syndrome - See Dwarfism, mental retardation and eye abnormality
* Moloney syndrome
* Molybdenum cofactor deficiency
* MOMO syndrome
* MONA - See Torg Winchester syndrome
* Monday morning fever - See Byssinosis
* Mondini dysplasia
* Mondor disease
* Monilethrix
* Monkeypox
* Monkeypox virus infection - See Monkeypox
* Monocarboxylate transporter-8 deficiency - See Allan-Herndon-Dudley syndrome
* Monoclonal gammopathy of undetermined significance
* Monocyte - B - natural killer - dendritic cell deficiency - See Dendritic cell, monocyte, B lymphocyte, and natural killer lymphocyte deficiency
* Monocytic sarcoma (cell type) - See Myeloid sarcoma
* Monocytopenia and mycobacterial infection syndrome - See Dendritic cell, monocyte, B lymphocyte, and natural killer lymphocyte deficiency
* Monocytopenia with susceptibility to infections - See Dendritic cell, monocyte, B lymphocyte, and natural killer lymphocyte deficiency
* Monocytopenia with susceptibility to mycobacterial, fungal, and papillomavirus infections and myelodysplasia - See Dendritic cell, monocyte, B lymphocyte, and natural killer lymphocyte deficiency
*   Monogenic diabetes
* MONOMAC - See Dendritic cell, monocyte, B lymphocyte, and natural killer lymphocyte deficiency
* Monomelic amyotrophy
* Monomodal visual amnesia - See Agnosia
* Monomorphic clear cell tumor - See Epithelial-myoepithelial carcinoma
* Mononen Karnes Senac syndrome - See Brachydactyly Mononen type
* Mononeuritis multiplex
* Monosaccharide malabsorption - See Glucose-galactose malabsorption
* Monosomy 10p - See Chromosome 10p deletion
* Monosomy 10q - See Chromosome 10q deletion
* Monosomy 11p - See Chromosome 11p deletion
* Monosomy 11q - See Chromosome 11q deletion
* Monosomy 12p - See Chromosome 12p deletion
* Monosomy 12q - See Chromosome 12q deletion
* Monosomy 13q - See Chromosome 13q deletion
* Monosomy 14q - See Chromosome 14q deletion
* Monosomy 15q - See Chromosome 15q deletion
* Monosomy 16p - See Chromosome 16p deletion
* Monosomy 16p11.2 - See 16p11.2 deletion syndrome
* Monosomy 16q - See Chromosome 16q deletion
* Monosomy 16q24.3 - See 16q24.3 microdeletion syndrome
* Monosomy 17p - See Chromosome 17p deletion
* Monosomy 17q - See Chromosome 17q deletion
* Monosomy 17q21.31 - See Koolen de Vries syndrome
* Monosomy 17q23.1q23.2 - See 17q23.1q23.2 microdeletion syndrome
* Monosomy 17q23.1-q23.2 - See 17q23.1q23.2 microdeletion syndrome
* Monosomy 18 mosaicism - See Mosaic monosomy 18
* Monosomy 18q syndrome - See Proximal chromosome 18q deletion syndrome
* Monosomy 18q syndrome - See Distal chromosome 18q deletion syndrome
* Monosomy 19p - See Chromosome 19p deletion
* Monosomy 19p13.12 - See 19p13.12 microdeletion syndrome
* Monosomy 19q - See Chromosome 19q deletion
* Monosomy 1p - See Chromosome 1p deletion
* Monosomy 1p36 syndrome - See Chromosome 1p36 deletion syndrome
* Monosomy 1q - See Chromosome 1q deletion
* Monosomy 1q21.1 - See 1q21.1 microdeletion syndrome
* Monosomy 1q41-q42 - See Chromosome 1q41-q42 deletion syndrome
* Monosomy 1q44 - See 1q44 microdeletion syndrome
* Monosomy 20p - See Chromosome 20p deletion
* Monosomy 20q - See Chromosome 20q deletion
* Monosomy 21q - See Chromosome 21q deletion
* Monosomy 22 mosaicism - See Mosaic monosomy 22
* Monosomy 22q - See Chromosome 22q deletion
* Monosomy 22q13 - See 22q13.3 deletion syndrome
* Monosomy 2p - See Chromosome 2p deletion
* Monosomy 2q - See Chromosome 2q deletion
* Monosomy 2q23.1 - See 2q23.1 microdeletion syndrome
* Monosomy 2q24 - See Chromosome 2q24 microdeletion syndrome
* Monosomy 3p - See Chromosome 3p deletion
* Monosomy 3q - See Chromosome 3q deletion
* Monosomy 4p - See Chromosome 4p deletion
* Monosomy 4q - See Chromosome 4q deletion
* Monosomy 5p - See Chromosome 5p deletion
* Monosomy 5p - See Cri du chat syndrome
* Monosomy 5q - See Chromosome 5q deletion
* Monosomy 5q14.3 - See 5q14.3 microdeletion syndrome
* Monosomy 6p - See Chromosome 6p deletion
* Monosomy 6q - See Chromosome 6q deletion
* Monosomy 6q25 - See Chromosome 6q25 microdeletion syndrome
* Monosomy 7p - See Chromosome 7p deletion
* Monosomy 7q - See Chromosome 7q deletion
* Monosomy 8p - See Chromosome 8p deletion
* Monosomy 8p23.1 - See Chromosome 8p23.1 deletion
* Monosomy 8q - See Chromosome 8q deletion
* Monosomy 8q24.1 - See Trichorhinophalangeal syndrome type 2
* Monosomy 9p - See Chromosome 9p deletion
* Monosomy 9q - See Chromosome 9q deletion
* Monosomy Xp - See Chromosome Xp deletion
* Monosomy Xq - See Chromosome Xq deletion
* Montefiore syndrome
* Moore Federman syndrome - See Dwarfism stiff joint ocular abnormalities
* Moore Weaver syndrome - See Distal arthrogryposis Moore Weaver type
* MOPD 1 - See Microcephalic osteodysplastic primordial dwarfism type 1
* MOPD 2 - See Microcephalic osteodysplastic primordial dwarfism type 2
* MOPD II - See Microcephalic osteodysplastic primordial dwarfism type 2
* Moran-Barroso Syndrome - See Orofaciodigital syndrome 12
* Morel's ear
* Morgagni-Stewart-Morel syndrome
* Morgellons
* Morgellon's - See Morgellons
* Morillo-Cucci-Passarge syndrome
* MORM syndrome
* Morphea
* Morquio A disease - See Morquio syndrome A
* Morquio syndrome A
* Morquio syndrome B
* Morquio syndrome C
* Morquio syndrome nonkeratosulfate-excreting type - See Morquio syndrome C
* Morsch Woltman syndrome - See Stiff person syndrome
* Morse-Rawnsley-Sargent syndrome
* Morvan disease - See Hereditary sensory and autonomic neuropathy type 2
* Morvan's fibrillary chorea
* Mosaic monosomy 18
* Mosaic monosomy 22
* Mosaic monosomy chromosome 18 - See Mosaic monosomy 18
* Mosaic monosomy chromosome 22 - See Mosaic monosomy 22
* Mosaic tetrasomy 9p - See Tetrasomy 9p
* Mosaic triploidy - See Diploid-triploid mosaicism
* Mosaic trisomy 10 - See Chromosome 10, uniparental disomy
* Mosaic trisomy 13
* Mosaic trisomy 14
* Mosaic trisomy 16 - See Chromosome 16 trisomy
* Mosaic trisomy 1q12 q21 - See Chromosome 1, uniparental disomy 1q12 q21
* Mosaic trisomy 20 - See Chromosome 20 trisomy
* Mosaic trisomy 21 - See Chromosome 21, uniparental disomy
* Mosaic trisomy 22
* Mosaic trisomy 6
* Mosaic trisomy 7
* Mosaic trisomy 8
* Mosaic trisomy 9
* Mosaic trisomy chromosome 13 - See Mosaic trisomy 13
* Mosaic trisomy chromosome 14 - See Mosaic trisomy 14
* Mosaic trisomy chromosome 22 - See Mosaic trisomy 22
* Mosaic trisomy chromosome 7 - See Mosaic trisomy 7
* Mosaic trisomy chromosome 8 - See Mosaic trisomy 8
* Mosaic trisomy chromosome 9 - See Mosaic trisomy 9
* Mosaic trisomy of chromosome 5 - See Chromosome 5, uniparental disomy
* Mosaic variegated aneuploidy syndrome
* Moschowitz syndrome - See Thrombotic thrombocytopenic purpura, acquired
* MOTA syndrome - See Manitoba oculotrichoanal syndrome
* Motor neuro-ophthalmic disorders - See Ocular motility disorders
* Motor neuro-ophthalmic disorders
* Motor neuropathy peripheral with dysautonomia
* Motor neuropathy, distal, Jerash type - See Neuropathy, distal hereditary motor, Jerash type
* Motor sensory neuropathy type 1 aplasia cutis congenita
* Mounier Kuhn syndrome - See Mounier-Kuhn syndrome
* Mounier-Kuhn syndrome
* Mountain sickness - See Acute mountain sickness
* Mount-Reback syndrome - See Dystonia 8
* Mousa Al din Al Nassar syndrome
* Mowat-Wilson syndrome
* Moyamoya disease
* Moyamoya disease 1 - See Moyamoya disease
* Moyamoya disease 2 - See Moyamoya disease
* Moyamoya disease 3 - See Moyamoya disease
* Moyamoya disease, primary - See Moyamoya disease
* Moyamoya disease, secondary - See Moyamoya disease
* Moyamoya syndrome - See Moyamoya disease
* Moynahan alopecia syndrome - See Alopecia epilepsy oligophrenia syndrome of Moynahan
* Moynahan syndrome - See Alopecia epilepsy oligophrenia syndrome of Moynahan
* MPD2 - See Distal myopathy with vocal cord weakness
* MPGN - See Membranoproliferative glomerulonephritis
* MPGN 2 - See Dense deposit disease
* MPI deficiency - See Congenital disorder of glycosylation type 1B
* MPKU - See Maternal hyperphenylalaninemia
* MPNST - See Malignant peripheral nerve sheath tumor
* MPO deficiency - See Myeloperoxidase deficiency
* MPPC syndrome - See Microcornea posterior megalolenticonus persistent fetal vasculature coloboma
* MPPH syndrome - See Megalencephaly, polymicrogyria, and hydrocephalus (MPPH) syndrome
* MPS - See Mucopolysaccharidosis
* MPS 1 - See Mucopolysaccharidosis type I
* MPS 2 - See Mucopolysaccharidosis type II
* MPS 3A - See Mucopolysaccharidosis type IIIA
* MPS 3B - See Mucopolysaccharidosis type IIIB
* MPS 3C - See Mucopolysaccharidosis type IIIC
* MPS 3D - See Mucopolysaccharidosis type IIID
* MPS 4A - See Morquio syndrome A
* MPS 4B - See Morquio syndrome B
* MPS 6 - See Mucopolysaccharidosis type VI
* MPS 7 - See Mucopolysaccharidosis type VII
* MPS I - See Mucopolysaccharidosis type I
* MPS II - See Mucopolysaccharidosis type II
* MPS IIIA - See Mucopolysaccharidosis type IIIA
* MPS IIIB - See Mucopolysaccharidosis type IIIB
* MPS IIIC - See Mucopolysaccharidosis type IIIC
* MPS IIID - See Mucopolysaccharidosis type IIID
* MPS IVA - See Morquio syndrome A
* MPS IVB - See Morquio syndrome B
* MPS VI - See Mucopolysaccharidosis type VI
* MPS VII - See Mucopolysaccharidosis type VII
* MPV17-related hepatocerebral mitochondrial DNA depletion syndrome
* MRD - See Multicystic renal dysplasia, bilateral
* MRK anomaly - See Mayer-Rokitansky-Kuster-Hauser syndrome
* MRKH anomaly - See Mayer-Rokitansky-Kuster-Hauser syndrome
* MRKH syndrome - See Mayer-Rokitansky-Kuster-Hauser syndrome
* MROS - See Melkersson-Rosenthal syndrome
* MRS - See Melkersson-Rosenthal syndrome
* MRX14 - See Mental retardation, X-linked 14
* MRX21 - See Mental retardation, X-linked, nonspecific
* MRX60 (formerly) - See Mental retardation x-linked with cerebellar hypoplasia and distinctive facial appearance
* MRXHF1 - See Mental retardation-hypotonic facies syndrome X-linked, 1
* MRXS Christianson - See Christianson syndrome
* MRXS1 - See Partington X-linked mental retardation syndrome
* MRXS11 - See Mental retardation X-linked syndromic 11
* MRXS13 - See PPM-X syndrome
* MRXS2 - See Prieto X-linked mental retardation syndrome
* MRXS3 - See Renpenning syndrome 1
* MRXS4 - See Miles-Carpenter x-linked mental retardation syndrome
* MRXS5 - See Dandy-Walker malformation with mental retardation basal ganglia disease and seizures
* MRXS6 - See Wilson-Turner X-linked mental retardation syndrome
* MRXS7 - See Mental retardation X-linked syndromic 7
* MRXS8 - See Renpenning syndrome 1
* MRXSAB - See Abidi X-linked mental retardation syndrome
* MRXSL - See Lubs X-linked mental retardation syndrome
* MRXSSD - See Siderius X-linked mental retardation syndrome
*   MS - See Multiple sclerosis
* MS pediatric - See Pediatric multiple sclerosis
* MSA - See Multiple system atrophy
* MSBD syndrome
* MSBD with MR - See Sclerosing bone dysplasia mental retardation
* MSD - See Multiple sulfatase deficiency
*   Mseleni joint disease - See Handigodu disease
* MSM syndrome - See Morgagni-Stewart-Morel syndrome
* MSMD - See Atypical mycobacteriosis, familial
* MSPKA - See Megalocornea - spherophakia - secondary glaucoma
* MSS - See Marinesco-Sjogren syndrome
* MSSD - See Syndactyly type 9
* MSSE - See Multiple self healing squamous epithelioma
* MSTD - See Frontotemporal dementia
* MSUD - See Maple syrup urine disease
* MSUD due to deficiency of e1-beta subunit of branched-chain alpha-keto acid dehydrogenase complex - See Maple syrup urine disease type 1B
* MSUD type 1A - See Maple syrup urine disease type 1A
* MSUD type 2 - See Maple syrup urine disease type 2
* MSUD type 3 (formerly) - See Maple syrup urine disease type 1B
* MSUD type IB - See Maple syrup urine disease type 1B
* MSUD2 - See Maple syrup urine disease type 2
* MTDPS6 - See MPV17-related hepatocerebral mitochondrial DNA depletion syndrome
*   MTHFR gene mutation
* MTS - See Mohr-Tranebjaerg syndrome
* Mucha-Habermann disease - See Pityriasis lichenoides et varioliformis acuta
* Mucinous adenocarcinoma - See Adenocarcinoma of the appendix
* Mucinous carcinoid - See Goblet cell carcinoid
* Muckle Wells syndrome - See Muckle-Wells syndrome
* Muckle-Wells syndrome
* Mucocutaneous exfoliative disease - See Toxic epidermal necrolysis
* Mucocutaneous lymph node syndrome - See Kawasaki syndrome
* Mucoepidermoid carcinoma
* Mucoepithelial dysplasia, hereditary - See Hereditary mucoepithelial dysplasia
* Mucolipidosis 2 - See I cell disease
* Mucolipidosis III alpha/beta
* Mucolipidosis type 1 - See Sialidosis, type II
* Mucolipidosis type 3A - See Mucolipidosis III alpha/beta
* Mucolipidosis type 4
* Mucopolysaccharidosis
* Mucopoly-saccharidosis type 3 - See Mucopolysaccharidosis type III
* Mucopoly-saccharidosis type 3A - See Mucopolysaccharidosis type IIIA
* Mucopoly-saccharidosis type 3B - See Mucopolysaccharidosis type IIIB
* Mucopoly-saccharidosis type 3C - See Mucopolysaccharidosis type IIIC
* Mucopoly-saccharidosis type 3D - See Mucopolysaccharidosis type IIID
* Mucopolysaccharidosis type 6 - See Mucopolysaccharidosis type VI
* Mucopolysaccharidosis type 7 - See Mucopolysaccharidosis type VII
* Mucopolysaccharidosis type I
* Mucopolysaccharidosis type II
* Mucopolysaccharidosis type III
* Mucopolysaccharidosis type IIIA
* Mucopolysaccharidosis type IIIB
* Mucopolysaccharidosis type IIIC
* Mucopolysaccharidosis type IIID
* Mucopolysaccharidosis type IVA - See Morquio syndrome A
* Mucopolysaccharidosis type IVB - See Morquio syndrome B
* Mucopolysaccharidosis type VI
* Mucopoly-saccharidosis type VI - See Mucopolysaccharidosis type VI
* Mucopolysaccharidosis type VII
* Mucosal lacerations - gastroesophageal junction - See Mallory-Weiss syndrome
* Mucosal neuroma syndrome - See Multiple endocrine neoplasia type 2B
* Mucosulfatidosis - See Multiple sulfatase deficiency
* Mucoviscidosis - See Cystic fibrosis
* Mud fever - See Leptospirosis
* Muenke nonsyndromic coronal craniosynostosis - See Muenke Syndrome
* Muenke Syndrome
* MUHH - See Marie Unna congenital hypotrichosis
* Muir-Torre syndrome
* Mulberry teeth - See Hutchinson incisors
* Mulibrey Nanism
* Muller Barth Menger syndrome
* Mullerian adenosarcoma of the uterus - See Adenosarcoma of the uterus
* Mullerian agenesis
* Mullerian aplasia
* Mullerian aplasia with hypoplastic thumbs - See Michels Caskey syndrome
* Mullerian aplasia with unilateral hypoplasia of the thumbs and skeletal spine deformities - See Michels Caskey syndrome
* Mullerian derivatives, persistence of, with lymphangiectasia and postaxial polydactyly - See Persistence of mullerian derivatives with lymphangiectasia and postaxial polydactyly
* Mullerian duct aplasia, unilateral renal agenesis, and cervicothoracic somite anomalies - See MURCS association
* Mullerian duct failure - See Mullerian aplasia
* Multicentric Castleman’s Disease
* Multicentric osteolysis nephropathy
* Multicentric osteolysis, nodulosis and arthropathy - See Torg Winchester syndrome
* Multicentric plasma cell variant of Castleman's disease - See Multicentric Castleman’s Disease
* Multicentric reticulohistiocytosis
* Multicore disease
* Multicore myopathy with external ophthalmoplegia - See Minicore myopathy with external ophthalmoplegia
* Multicore myopathy with mental retardation, short stature, and hypogonadotropic hypogonadism - See Chudley Rozdilsky syndrome
* Multicore myopathy, antenatal onset, with arthrogryposis - See Minicore myopathy, antenatal onset, with arthrogryposis
* Multicore myopathy, severe classic form - See Rigid spine syndrome
* Multicystic renal dysplasia, bilateral
* Multifocal choroiditis
* Multifocal fibrosclerosis
* Multifocal lymphangioendotheliomatosis with thrombocytopenia
* Multifocal motor neuropathy
* Multifocal motor neuropathy with conduction block
* Multifocal osteomyelitis, chronic - See Chronic recurrent multifocal osteomyelitis
* Multifocal placoid pigment epitheliopathy - See Acute posterior multifocal placoid pigment epitheliopathy
* Multifocal ventricular premature beats - See Catecholaminergic polymorphic ventricular tachycardia
* Multi-infarct dementia - See Binswanger's disease
* Multilocular peritoneal cysts - See Benign multicystic peritoneal mesothelioma
* Multilocular peritoneal inclusion cysts - See Benign multicystic peritoneal mesothelioma
* Multiminicore disease with external ophthalmoplegia - See Minicore myopathy with external ophthalmoplegia
* Multiminicore disease, severe classic form - See Rigid spine syndrome
* Multiminicore myopathy, antenatal onset, with arthrogryposis - See Minicore myopathy, antenatal onset, with arthrogryposis
* Multinodular goiter - cystic kidney - polydactyly - See Daneman Davy Mancer syndrome
* Multinodular goiter, cystic renal disease, and digital anomalies - See Daneman Davy Mancer syndrome
* Multiocre myopathy - See Multicore disease
* Multiple Acyl-CoA dehydrogenase deficiency - See Glutaric acidemia type II
* Multiple Angiomas and Endochondromas - See Maffucci syndrome
* Multiple basal cell carcinoma - See Basal cell carcinoma, multiple
* Multiple Basal Cell Nevi, Odontogenic Keratocysts, And Skeletal Anomalies - See Nevoid basal cell carcinoma syndrome
* Multiple cafe´-au-lait spots - See Neurofibromatosis type 6
* Multiple cafe´-au-lait syndrome - See Neurofibromatosis type 6
* Multiple cafe-au-lait spots - See Cafe au lait spots, multiple
* Multiple carboxylase deficiency, biotin responsive
* Multiple carboxylase deficiency, propionic acidemia
* Multiple cartilaginous enchondroses - See Ollier disease
* Multiple congenital anomalies mental retardation, growth failure and cleft lip palate
* Multiple congenital anomalies, mental retardation and progressive skeletal sclerosis - See Lenz Majewski hyperostotic dwarfism
* Multiple congenital anomalies, severe psychomotor retardation and symmetrical circumferential skin creases of arms and legs - See Elliott Ludman Teebi syndrome
* Multiple contracture syndrome, Finnish type - See Lethal congenital contracture syndrome 1
* Multiple contracture syndrome, Israeli Bedouin type - See Lethal congenital contracture syndrome 2
* Multiple cutaneous and uterine leiomyomata - See Hereditary leiomyomatosis and renal cell cancer
* Multiple cutaneous leiomyomata - See Hereditary leiomyomatosis and renal cell cancer
* Multiple diaphyseal sclerosis - See Ribbing disease
* Multiple dysmorphic features and pancytopenia - See Sackey Sakati Aur syndrome
* Multiple enchondromatosis - See Ollier disease
* Multiple endocrine deficiency syndrome, type 2 - See Autoimmune polyglandular syndrome type 2
* Multiple endocrine neoplasia type 1
* Multiple endocrine neoplasia type 2
* Multiple endocrine neoplasia type 2A
* Multiple endocrine neoplasia type 2B
* Multiple endocrine neoplasia, type 3 (formerly) - See Multiple endocrine neoplasia type 2B
* Multiple epiphyseal dysplasia
* Multiple epiphyseal dysplasia 1
* Multiple epiphyseal dysplasia 2
* Multiple epiphyseal dysplasia 3
* Multiple epiphyseal dysplasia 4
* Multiple epiphyseal dysplasia 5
* Multiple epiphyseal dysplasia COMP-related - See Multiple epiphyseal dysplasia 1
* Multiple epiphyseal dysplasia with bilayered patellae - See Multiple epiphyseal dysplasia 4
* Multiple epiphyseal dysplasia with clubfoot - See Multiple epiphyseal dysplasia 4
* Multiple epiphyseal dysplasia with double-layered patella - See Multiple epiphyseal dysplasia 4
* Multiple epiphyseal dysplasia, autosomal recessive - See Multiple epiphyseal dysplasia 4
* Multiple epiphyseal dysplasia, MATN3 related - See Multiple epiphyseal dysplasia 5
* Multiple exostoses - See Hereditary multiple osteochondromas
* Multiple exostoses with spastic tetraparesis - See Spasticity multiple exostoses
* Multiple familial trichoepithelioma
* Multiple familial trichoepithelioma 1
* Multiple familial trichoepithelioma 2
* Multiple fibrofolliculoma familial
* Multiple hamartoma syndrome - See Cowden syndrome
* Multiple joint dislocations metaphyseal dysplasia
* Multiple lentigines syndrome - See LEOPARD syndrome
* Multiple myeloma
* Multiple none-erupting teeth, maxillo-zygomatical hypoplasia and other congenital defects - See Teeth noneruption of with maxillary hypoplasia and genu valgum
* Multiple non-erupting teeth, maxillo-zygomatical hypoplasia and other congenital defects - See Stoelinga de Koomen Davis syndrome
* Multiple ophthalmic anomalies and digital hypoplasia - See Oculo digital syndrome
* Multiple orbital neurofibromas, painful peripheral nerve tumors, distinctive face and marfanoid habitus - See Painful orbital and systemic neurofibromas-marfanoid habitus syndrome
* Multiple osseous dysplasia, characteristic ear shape, and short stature - See Auriculoosteodysplasia
* Multiple pterygium syndrome - See Multiple pterygium syndrome Escobar type
* Multiple pterygium syndrome Aslan type
* Multiple pterygium syndrome Escobar type
* Multiple pterygium syndrome lethal type
* Multiple pterygium syndrome nonlethal type - See Multiple pterygium syndrome Escobar type
* Multiple pterygium syndrome X-linked
* Multiple respiratory chain enzyme deficiencies
*   Multiple sclerosis
* Multiple sclerosis, pediatric - See Pediatric multiple sclerosis
* Multiple sclerosis-like disorder - See Pelizaeus-Merzbacher disease, late-onset type
* Multiple sebaceous cysts - See Steatocystoma multiplex
* Multiple self healing squamous epithelioma
* Multiple small, cream-colored lesions, symmetrically scattered mainly around the optic disk - See Birdshot chorioretinopathy
* Multiple sulfatase deficiency
* Multiple symmetric lipomatosis - See Madelung disease
* Multiple synostoses syndrome 1
* Multiple synostoses syndrome 2
* Multiple system atrophy
* Multiple system atrophy (MSA) with orthostatic hypotension
* Multiple system atrophy with autonomic failure - See Multiple system atrophy (MSA) with orthostatic hypotension
* Multiple system tauopathy with presenile dementia - See Frontotemporal dementia
* Multiple vertebral anomalies unusual facies
* Multisynostotic osteodysgenesis with long bone fractures - See Antley Bixler syndrome
* Multisystem inflammatory disease, neonatal-onset - See Chronic Infantile Neurological Cutaneous Articular syndrome
* Mulvihill-Smith syndrome - See Progeroid short stature with pigmented nevi
* Mumps
* Munchausen by proxy syndrome
* Munchausen syndrome by proxy - See Munchausen by proxy syndrome
* Mungan syndrome
* MURCS association
* Murine typhus - See Typhus
* Murk Jansen type metaphyseal chondrodysplasia - See Jansen type metaphyseal chondrodysplasia
* Muscle contractions, tetanoform, with characteristic face, camptodactyly, hyperthermia, and sudden death - See Crisponi syndrome
* Muscle core disease - See Central core disease
* Muscle eye brain disease
* Muscle glycogen phosphorylase deficiency - See Glycogen storage disease type 5
* Muscle glycogen synthase deficiency - See Glycogen storage disease type 0, muscle
* Muscle phosphofructokinase deficiency - See Glycogen storage disease type 7
* Muscle phosphoglycerate mutase deficiency - See Phosphoglycerate mutase deficiency
* Muscle spasms, intermittent with alopecia, diarrhea and skeletal abnormalities - See Satoyoshi syndrome
* Muscle-eye-brain disease - See Muscle eye brain disease
* Muscle-liver-brain-eye nanism - See Mulibrey Nanism
* Muscular atrophy ataxia retinitis pigmentosa and diabetes mellitus
* Muscular atrophy, infantile - See Spinal muscular atrophy 1
* Muscular atrophy, juvenile - See Spinal muscular atrophy type 3
* Muscular atrophy, spinal, infantile chronic form - See Spinal muscular atrophy type 2
* Muscular atrophy, spinal, intermediate type - See Spinal muscular atrophy type 2
* Muscular central core disease - See Central core disease
* Muscular dystrophy
* Muscular Dystrophy - Late Onset
* Muscular dystrophy Hutterite type - See Limb-girdle muscular dystrophy type 2H
* Muscular dystrophy limb girdle type 2A, Erb type
* Muscular dystrophy limb-girdle type 2H - See Limb-girdle muscular dystrophy type 2H
* Muscular dystrophy limb-girdle with alpha-sarcoglycan - See Limb-girdle muscular dystrophy, type 2D
* Muscular dystrophy limb-girdle with beta-sarcoglycan deficiency - See Limb-girdle muscular dystrophy type 2E
* Muscular dystrophy limb-girdle with delta-sarcoglyan deficiency - See Limb-girdle muscular dystrophy type 2F
* Muscular dystrophy pseudohypertrophic progressive, Becker type - See Becker muscular dystrophy
* Muscular dystrophy white matter spongiosis
* Muscular dystrophy, Becker type - See Becker muscular dystrophy
* Muscular dystrophy, benign congenital - See Bethlem myopathy
* Muscular dystrophy, congenital progressive, with mental retardation - See Fukuyama type muscular dystrophy
* Muscular dystrophy, congenital, Fukuyama type - See Fukuyama type muscular dystrophy
* Muscular dystrophy, congenital, infantile with cataract and hypogonadism
* Muscular dystrophy, congenital, megaconial type
* Muscular dystrophy, congenital, merosin positive with early spine rigidity - See Rigid spine syndrome
* Muscular dystrophy, congenital, merosin-deficient - See Congenital muscular dystrophy type 1A
* Muscular dystrophy, congenital, merosin-positive
* Muscular dystrophy, congenital, with central nervous system involvement - See Fukuyama type muscular dystrophy
* Muscular dystrophy, distal, late onset, autosomal recessive - See Miyoshi myopathy
* Muscular dystrophy, Duchenne - See Duchenne muscular dystrophy
* Muscular dystrophy, Duchenne-like - See Limb-girdle muscular dystrophy, type 2C
* Muscular dystrophy, facioscapulohumeral - See Facioscapulohumeral muscular dystrophy
* Muscular dystrophy, facioscapulohumeral, type 1a - See Facioscapulohumeral muscular dystrophy
* Muscular dystrophy, limb-girdle, type 2G - See Limb-girdle muscular dystrophy, type 2G
* Muscular dystrophy, limb-girdle, type 3 - See Limb-girdle muscular dystrophy, type 2B
* Muscular dystrophy, oculogastrointestinal - See Familial visceral myopathy with external ophthalmoplegia
* Muscular dystrophy, oculopharyngeal - See Oculopharyngeal muscular dystrophy
* Muscular dystrophy, pelvofemoral - See Limb-girdle muscular dystrophy, type 2A
* Muscular dystrophy, proximal, type 1A - See Limb-girdle muscular dystrophy, type 1A
* Muscular dystrophy, proximal, type 1B - See Limb-girdle muscular dystrophy, type 1B
* Muscular dystrophy, pseudohypertrophic progressive, Duchenne type - See Duchenne muscular dystrophy
* Muscular dystrophy, tardive Emery-Dreifuss type, with contractures - See Emery-Dreifuss muscular dystrophy, X-linked
* Muscular dystrophy, tardive, Dreifuss-Emery type, with contractures - See Emery-Dreifuss muscular dystrophy
* Muscular fibrosis multifocal obstructed vessels
* Muscular phosphorylase kinase deficiency
* Mutagen sensitivity
* Mutchinick syndrome - See Intellectual deficit Buenos-Aires type
* Mutilating keratoderma - See Vohwinkel syndrome
* Mutiple parosteal osteochondromatous proliferations
* MVA syndrome - See Mosaic variegated aneuploidy syndrome
* MVP - See Mitral valve prolapse, familial, X-linked
* MWS - See Marden-Walker syndrome
*   Myalgic encephalomyelitis - See Chronic fatigue syndrome
* Myasthenia familial infantile - See Congenital myasthenic syndrome with episodic apnea
* Myasthenia gravis
* Myasthenia gravis congenital
* Myasthenia gravis familial infantile 2 (formerly) - See Congenital myasthenic syndrome with episodic apnea
* Myasthenia gravis pseudoparalytica - See Myasthenia gravis congenital
* Myasthenia gravis, limb-girdle
* Myasthenia, limb-girdle, autoimmune - See Myasthenia gravis, limb-girdle
* Myasthenic syndrome congenital associated with episodic apnea - See Congenital myasthenic syndrome with episodic apnea
* Myasthenic syndrome of Lambert-Eaton - See Lambert Eaton myasthenic syndrome
* Myasthenic syndrome, congenital, associated with acetylcholine receptor deficiency - See Congenital myasthenic syndrome associated with acetylcholine receptor deficiency
* Myasthenic syndrome, congenital, postsynaptic slow-channel - See Slow-channel congenital myasthenic syndrome
* Myasthenic syndrome, congenital, postsynaptic, associated with acetylcholine receptor deficiency - See Congenital myasthenic syndrome associated with acetylcholine receptor deficiency
* Myasthenic syndrome, congenital, slow-channel - See Slow-channel congenital myasthenic syndrome
* Myasthenic syndrome, congenital, type id - See Congenital myasthenic syndrome associated with acetylcholine receptor deficiency
* Myasthenic syndrome, congenital, type IIa - See Slow-channel congenital myasthenic syndrome
* Myasthenic syndrome, presynaptic, congenital, associated with episodic apnea - See Congenital myasthenic syndrome with episodic apnea
* Myasthenic-Myopathic syndrome of Lambert-Eaton - See Lambert Eaton myasthenic syndrome
* Mycetoma
* Mycobacterial disease, Mendelian susceptibility to - See Atypical mycobacteriosis, familial
* Mycobacterium Abscessus
* Mycobacterium Abscessus infection - See Mycobacterium Abscessus
* Mycobacterium Avium - See Mycobacterium Avium Complex
* Mycobacterium Avium Complex
* Mycobacterium Avium-Intracellulare - See Mycobacterium Avium Complex
* Mycobacterium Avium-Intracellulare infection - See Mycobacterium Avium Complex
* Mycobacterium Chelonae
* Mycobacterium Chelonae infection - See Mycobacterium Chelonae
* Mycobacterium fortuitum
* Mycobacterium Fortuitum infection - See Mycobacterium fortuitum
* Mycobacterium Gordonae
* Mycobacterium Gordonae infection - See Mycobacterium Gordonae
* Mycobacterium Intracellulare - See Mycobacterium Avium Complex
* Mycobacterium Kansasii
* Mycobacterium Kansasii infection - See Mycobacterium Kansasii
* Mycobacterium Malmoense
* Mycobacterium Malmoense infection - See Mycobacterium Malmoense
* Mycobacterium Marinum
* Mycobacterium Marinum infection - See Mycobacterium Marinum
* Mycobacterium tuberculosis, susceptibility to infection by
* Mycobacterium Xenopi
* Mycobacterium Xenopi infection - See Mycobacterium Xenopi
* Mycoplasmal pneumonia
* Mycosis fungoides
* Myelinosis centralis diffusa - See Leukoencephalopathy with vanishing white matter
* Myelitis
* Myelocerebellar disorder
* Myelocytic leukemia-like syndrome, familial, chronic
* Myelodysplastic syndromes
* Myelodysplastic/myeloproliferative disease
* Myelodysplastic/myeloproliferative neoplasm - See Myelodysplastic/myeloproliferative disease
* Myelofibrosis
* Myeloid leukemia - See Leukemia, Myeloid
* Myeloid metaplasia - See Myelofibrosis
* Myeloid sarcoma
* Myeloid splenomegaly
* Myeloma - multiple - See Multiple myeloma
* Myelomatosis - See Multiple myeloma
* Myelomeningocele
* Myeloperoxidase deficiency
* MYH7-related scapuloperoneal myopathy
* MYH9 related disorders - See MYH9 related thrombocytopenia
* MYH9 related thrombocytopenia
* MYH-associated polyposis
* Myhre syndrome
* MYMY - See Moyamoya disease
* Myoadenylate deaminase deficiency - See Adenosine monophosphate deaminase 1 deficiency
* Myocardial calcifications resulting in intrauterine fetal death - See Cardiomyopathy, fatal fetal, due to myocardial calcification
* Myocardial tumors (rhabdomyomas and fibromas) - See Heart tumor
* Myocarditis
* Myoclonic astatic epilepsy
* Myoclonic dystonia - See Dystonia 11
* Myoclonic epilepsy associated with ragged-red fibers - See Myoclonus with epilepsy with ragged red fibers
* Myoclonic epilepsy of Lafora - See Lafora disease
* Myoclonic epilepsy of Unverricht and Lundborg - See Unverricht-Lundborg disease
* Myoclonic epilepsy with choreoathetosis - See Dentatorubral-pallidoluysian atrophy
* Myoclonic epilepsy, juvenile, 1 - See Juvenile myoclonic epilepsy
* Myoclonic epilepsy, severe, of infancy - See Dravet syndrome
* Myoclonic nystagmus - See Nystagmus, myoclonic
* Myoclonus and ataxia - See Dyssynergia cerebellaris myoclonica
* Myoclonus ataxia
* Myoclonus cerebellar ataxia deafness
* Myoclonus cherry red spot syndrome - See Sialidosis type I
* Myoclonus epilepsy
* Myoclonus epilepsy partial seizure
* Myoclonus hereditary progressive distal muscular atrophy
* Myoclonus progressive epilepsy of Unverricht and Lundborg - See Unverricht-Lundborg disease
* Myoclonus with epilepsy with ragged red fibers
* Myoclonus, hereditary essential - See Dystonia 11
* Myoclonus-dystonia - See Dystonia 11
* Myoclonus-dystonia syndrome - See Dystonia 11
* Myodystrophia fetalis deformans - See Arthrogryposis multiplex congenita
* Myoencephalopathy ragged-red fiber disease - See Myoclonus with epilepsy with ragged red fibers
* Myoepithelial carcinoma
* Myoepithelioma carcinoma - See Myoepithelial carcinoma
* Myofibrillar lysis
* Myofibrillar myopathy
* Myoglobinuria dominant form
* Myoglobinuria recurrent
* Myokymia with neonatal epilepsy
* Myoneurogastrointestinal encephalopathy syndrome - See Mitochondrial neurogastrointestinal encephalopathy syndrome
* Myopathic carnitine deficiency
* Myopathy congenital
* Myopathy congenital multicore with external ophthalmoplegia
* Myopathy distal, type 1 - See Laing distal myopathy
* Myopathy due to phosphoglycerate mutase deficiency - See Phosphoglycerate mutase deficiency
* Myopathy growth and mental retardation hypospadias
* Myopathy mitochondrial cataract
* Myopathy with cataract and combined respiratory-chain deficiency - See Myopathy, mitochondrial progressive, with congenital cataract, hearing loss, and developmental delay
* Myopathy with congenital joint contractures, ophthalmoplegia, and rimmed vacuoles - See Inclusion body myopathy 3
* Myopathy with lactic acidosis and sideroblastic anemia - See Sideroblastic anemia and mitochondrial myopathy
* Myopathy with lobulated fibers - See Trabecular myopathy
* Myopathy with lysis of myofibrils
* Myopathy, areflexia, respiratory distress, and dysphagia, early-onset - See Early-onset myopathy, areflexia, respiratory distress and dysphagia
* Myopathy, benign congenital, with contractures - See Bethlem myopathy
* Myopathy, central core - See Central core disease
* Myopathy, central fibrillar - See Central core disease
* Myopathy, congenital nonprogressive with Moebius and Robin sequences - See Congenital nonprogressive myopathy with Moebius and Robin sequences
* Myopathy, congenital with fiber-type disproportion - See Congenital fiber type disproportion
* Myopathy, distal, 2 - See Distal myopathy with vocal cord weakness
* Myopathy, lactic acidosis and sideroblastic anemia - See Sideroblastic anemia and mitochondrial myopathy
* Myopathy, limb-girdle, with bone fragility
* Myopathy, mitochondrial progressive, with congenital cataract, hearing loss, and developmental delay
* Myopathy, myotubular - See Centronuclear myopathy
* Myopathy, tubular aggregate - See Tubular aggregate myopathy
* Myopathy, X-linked, with excessive autophagy - See X-linked myopathy with excessive autophagy
* Myophosphorylase deficiency - See Glycogen storage disease type 5
* Myopia 6
* Myopia retinal detachment encephalocele - See Knobloch syndrome
* Myopia, susceptibility to - See Myopia 6
* Myopia-night blindness - See X-linked congenital stationary night blindness
* Myositis - See Idiopathic myopathy
* Myositis ossificans - See Fibrodysplasia ossificans progressiva
* Myositis ossificans progressiva - See Fibrodysplasia ossificans progressiva
* Myostatin-related muscle hypertrophy
* Myotilinopathy (type) - See Myofibrillar myopathy
* Myotonia atrophica - See Myotonic dystrophy
* Myotonia atrophica
* Myotonia congenita autosomal dominant
* Myotonia congenita autosomal recessive
* Myotonia congenita intermittens - See Paramyotonia congenita
* Myotonia congenita, acetazolamide-responsive - See Potassium aggravated myotonia
* Myotonia congenita, atypical - See Potassium aggravated myotonia
* Myotonia dystrophica - See Myotonic dystrophy
* Myotonia fluctuans - See Potassium aggravated myotonia
* Myotonia generalized - See Myotonia congenita autosomal recessive
* Myotonia mental retardation skeletal anomalies
* Myotonia permanens - See Potassium aggravated myotonia
* Myotonic dystrophy
* Myotonic dystrophy type 1
* Myotonic dystrophy type 2
* Myotonic myopathy dwarfism chondrodystrophy and ocular and facial abnormalities - See Schwartz Jampel syndrome type 1
* Myotonic myopathy with cylindrical spirals - See Cylindrical spirals myopathy
* Myotonic myopathy, proximal - See Myotonic dystrophy type 2
* Myotubular myopathy - See Centronuclear myopathy
* MYP6 - See Myopia 6
* Myxoid liposarcoma
* Myxoma, spotty pigmentation, and endocrine overactivity - See Carney complex
* Myxoma-spotty pigmentation-endocrine overactivity
* Myxomatous valvular disease, familial - See Mitral valve prolapse, familial, X-linked
* Myxomatous valvular dystrophy, X-linked - See Cardiac valvular dysplasia, X-linked
* Myxopapillary ependymoma
* Myxosporea - See Myxozoa
* Myxozoa