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Megalencephaly, polymicrogyria, and hydrocephalus (MPPH) syndrome


Other Names for this Disease
  • Megalencephaly and perisylvian polymicrogyria with postaxial polydactyly and hydrocephalus
  • MPPH syndrome
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Your Question

I would like to learn more about MPPH syndrome and how I can find other parents with children with this disorder.

Our Answer

We have identified the following information that we hope you find helpful. If you still have questions, please contact us.

What is megalencephaly, polymicrogyria, and hydrocephalus (MPPH) syndrome?

Megalencephaly, polymicrogyria, and hydrocephalus (MPPH) syndrome is a syndrome that is characterized by the presence of polymicrogyria, megalencephaly, mental retardation, seizures, polydactyly, and hydrocephalus. The cause of the condition is currently unknown.[1][2]
Last updated: 8/11/2008

What are the symptoms of megalencephaly, polymicrogyria, and hydrocephalus (MPPH) syndrome?

Common signs and symptoms of MPPH syndrome include polymicrogyria, megalencephaly, mental retardation, seizures, polydactyly, and hydrocephalus. Additional signs and symptoms reported in the medical literature, include thin corpus callosum, psychomotor retardation (i.e., slowing down of physical reactions, movements, and speech), impaired vision, low muscle tone, mild characteristic facial differences, macrosomia (often at birth), and infantile spasms.[1][2]
Last updated: 8/11/2008

What is polymicrogyria?

Polymicrogyria is a neuronal migration defect. It is essentially an abnormality in the development of the cerebral cortex, the outer layer of the brain. It can be recognized by the irregular appearance it creates on the surface of the brain.[3]
Last updated: 8/9/2008

What are the symptoms of polymicrogyria?

A wide variety of symptoms may be observed in people with polymicrogyria, including:[3]
  • Cognitive deficits
  • Epilepsy
  • Paralysis of the face, throat, and tongue
  • Difficulty with speech
  • Drooling
Last updated: 8/9/2008

Can polymicrogyria be associated with other conditions?

Yes. Polymicrogyria may be an isolated occurrence or it may be a part of a larger condition, chromosome abnormality, and/or syndrome. “Syndrome” is a term used to describe a condition that is characterized by a particular collection of symptoms. Examples of associated syndromes, include Aicardi syndrome, Zellweger syndrome, and Smith-Lemli-Opitz syndrome.[3]
Last updated: 8/9/2008

What is megalencephaly?

Megalencephaly, also called macrencephaly, is a condition in which there is an abnormally large heavy brain. By definition, the brain weight is greater than average for the age and gender of the individual. Head enlargement may be evident at birth or the head may become abnormally large in the early years of life.[4]
Last updated: 8/9/2008

What are the symptoms of megalencephaly?

Megalencephaly may cause no symptoms or be associated with developmental delay, seizures, and neurological problems.[4]
Last updated: 8/9/2008

Can megalencephaly be associated with other conditions?

Yes. Megalencephaly may be an isolated occurrence with normal cerebral structure, or associated with larger conditions or syndromes such as leukodystrophies and neurofibromatosis.[4][5]
Last updated: 8/9/2008

What is polydactyly?

Polydactyly is a condition in which a person has more than five fingers per hand. Extra digits may be poorly developed and attached by a small stalk, or may be well-formed and may even function.[6]
Last updated: 8/9/2008

Can polydactyly be associated with other conditions?

Yes. Polydactyly can occur on its own (e.g. familial polydactyly) or may be a part of a larger condition, chromosome abnormatlity, and/or syndrome. Examples of associated syndromes, include Carpenter syndrome, Ellis-van Creveld syndrome, Laurence-Moon-Biedl syndrome, Rubinstein-Taybi syndrome, and Smith-Lemli-Opitz syndrome. It can also occur in association with the chromosome abnormality Trisomy 13.[6]
Last updated: 8/9/2008

What kind of polydactyly is typically seen in people with megalencephaly, polymicrogyria, and hydrocephalus (MPPH) syndrome?

People with MPPH syndrome have post axial polydactyly, meaning the extra digit is on the outside of the little toe(s) or finger(s), and often times involves both hands and feet.[1]
Last updated: 8/11/2008

What is hydrocephalus?

Hydrocephalus is a condition characterized by excessive accumulation of fluid in the brain. Although it was once known as "water on the brain," the "water" is actually cerebrospinal fluid (CSF) - clear fluid that surrounds the brain and spinal cord. Excess CSF builds up when it cannot drain from the brain due to a blockage in a passage through which the fluid normally flows.  This excess fluid causes an abnormal widening of spaces in the brain called ventricles; this can create harmful pressure on brain tissue. Symptoms vary with age, disease progression, and individual differences in tolerance to the condition. Hydrocephalus may be congenital (present at birth) or acquired. The causes are not fully understood; it may result from inherited genetic abnormalities or developmental disorders; complications of premature birth; diseases such as meningitis; tumors; traumatic head injury; or other causes. It is most often treated by surgically inserting a shunt system.[7]
Last updated: 8/22/2011

Can hydrocephalus be associated with other conditions?

Yes. Hydrocephalus can occur due to a number of causes including head injuries, strokes, and infections. It can also be a part of a larger condition, chromosome abnormality, and/or syndrome, including megalencephaly, polymicrogyria, and hydrocephalus (MPPH) syndrome.
Last updated: 8/9/2008

What kind of hydrocephalus is typically seen in people with megalencephaly, polymicrogyria, and hydrocephalus (MPPH) syndrome?

The underlying cause of hydrocephalus in people with MPPH syndrome is not clear, however based upon the limited information avialable, it does not appear to be associated with the megalencephaly.[1]
Last updated: 8/11/2008

What causes megalencephaly, polymicrogyria, and hydrocephalus (MPPH) syndrome?

The cause of MPPH syndrome is unknown.[1] Infection during pregnancy or fetal accident is thought to be unlikely.[1]
Last updated: 8/9/2008

Is megalencephaly, polymicrogyria, and hydrocephalus (MPPH) syndrome genetic?

The genetics of MPPH syndrome is poorly understood. All cases described in the medical literature so far have been sporadic.[1] Sporadic conditions may indicate a genetic disorder that occurs for the first time in a family due to a new gene mutation or the chance occurrence of a non-genetic disorder or abnormality.
Last updated: 8/9/2008

How can I find other parents with children with megalencephaly, polymicrogyria, and hydrocephalus (MPPH) syndrome?

We recognize that it can be a challenge to find other families with children with the same condition, particularly when the condition is very rare like MPPH syndrome. The following advocacy organizations and online networks for patients with rare conditions and their families may be helpful as you search for other parents. You can register your child's disease with these sites and search for other families and allow other families to find you. You may also use these resources to find families with children with symptoms similar to those that affect your child.

RareShare is an online social hub dedicated to patients, families and healthcare professionals affected by rare medical disorders. Click on RareShare to learn more.

Family Village is a global community that integrates information, resources, and communication opportunities on the Internet for persons with cognitive and other disabilities, for their families, and for those who provide services and support. Click on Family Villiage to view the resource page on Myelin disorders. Myelin disorders encompass a variety of conditions including macroencephaly. You can explore Family Villiage to find resource pages on a variety of other topics/symptoms as well.

Last updated: 3/29/2013

References