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47 XXX syndrome


Other Names for this Disease

  • Triple X syndrome
  • Triple-X chromosome syndrome
  • Triple-X female
  • Triplo X syndrome
  • Trisomy X
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.

Overview

What is 47 XXX syndrome?

What are the signs and symptoms of 47 XXX syndrome?

Is 47 XXX syndrome inherited?

How is 47 XXX syndrome diagnosed?

How might 47 XXX syndrome be treated?

What is 47 XXX syndrome?

47 XXX syndrome, also called trisomy X, is characterized by the presence of an additional (third) X chromosome in each of a female's cells (which normally have two X chromosomes). An extra copy of the X chromosome is associated with tall stature, learning problems, and other features in some girls and women. Seizures or kidney abnormalities occur in about 10 percent of affected females. It is usually caused by a random event during the formation of reproductive cells (eggs and sperm). An error in cell division called nondisjunction can result in reproductive cells with an abnormal number of chromosomes. Treatment typically focuses on individual signs and symptoms that a person may have. Some females with trisomy X have an extra X chromosome in only some of their cells; this is called 46,XX/47,XXX mosaicism.[1]
Last updated: 9/24/2014

What are the signs and symptoms of 47 XXX syndrome?

Many women with 47 XXX syndrome have no symptoms or only mild symptoms. In other cases, symptoms may be more pronounced.[2] Females with 47 XXX syndrome may be taller than average, but the condition usually does not cause unusual physical features. Minor physical findings can be present in some individuals and may include epicanthal folds, hypertelorism (widely spaced eyes), upslanting palpebral fissures, clinodactyly, overlapping digits (fingers or toes), pes planus (flat foot), and pectus excavatum.[3] The condition is associated with an increased risk of learning disabilities and delayed development of speech and language skills. Delayed development of motor skills (such as sitting and walking), weak muscle tone (hypotonia), and behavioral and emotional difficulties are also possible, but these characteristics vary widely among affected girls and women. Seizures or kidney abnormalities occur in about 10 percent of affected females. Most females with the condition have normal sexual development and are able to conceive children.[1] However, some individuals have been found to have premature ovarian failure, or ovary abnormalities (such as malformed ovaries).[2]
Last updated: 9/24/2014

Is 47 XXX syndrome inherited?

Most cases of 47 XXX syndrome are not inherited. The chromosomal change usually occurs as a random event during the formation of reproductive cells (eggs and sperm). An error in cell division called nondisjunction can result in reproductive cells with an abnormal number of chromosomes. For example, an egg or sperm cell may gain an extra copy of the X chromosome as a result of nondisjunction. If one of these reproductive cells contributes to the genetic makeup of a child, the child will have an extra X chromosome in each of the body's cells. 46,XX/47,XXX mosaicism is also not inherited. It occurs as a random event during cell division in the early development of an embryo. As a result, some of an affected person's cells have two X chromosomes (46,XX), and other cells have three X chromosomes (47,XXX).[1]

Transmission of an abnormal number of X chromosomes from women with 47 XXX syndrome is rare, although it has been reported. Some reports suggest a <5% increased risk for a chromosomally abnormal pregnancy, and other more recent reports suggest that <1% may be more accurate. These risks are separate from the risks of having a chromosomally abnormal pregnancy due to maternal age or any other factors. Furthermore, these risks generally apply only to women with non-mosaic 47 XXX syndrome, as mosaicism may increase the risk of passing on an abnormal number of X chromosomes and potential outcomes.[3] Each individual with 47 XXX syndrome who is interested in learning about their own risks to have a child with a chromosome abnormality or other genetic abnormality should speak with their healthcare provider or a genetics professional.
Last updated: 9/24/2014

How is 47 XXX syndrome diagnosed?

47 XXX syndrome may first be suspected based on the presence of certain developmental, behavioral or learning disabilities in an individual. The diagnosis can be confirmed with chromosomal analysis (karyotyping), which can be performed on a blood sample. This test would reveal the presence of an extra X chromosome in body cells. 47 XXX syndrome may also be identified before birth (prenatally), based on chromosomal analysis performed on a sample taken during an amniocentesis or chorionic villus sampling (CVS) procedure.[4] However, in these cases, confirmation testing with a test called FISH is recommended in order to evaluate the fetus for mosaicism (when only a percentage of the cells have the extra X chromosome).[5]
Last updated: 9/24/2014

How might 47 XXX syndrome be treated?

There is no cure for 47 XXX syndrome, and there is no way to remove the extra X chromosome that is present in an affected individual's cells. Management of the condition varies and depends on several factors including the age at diagnosis, the specific symptoms that are present, and the overall severity of the disorder in the affected individual. Early intervention services are typically recommended for infants and children that are diagnosed with the condition. Specific recommendations include developmental assessment by 4 months of age to evaluate muscle tone and strength; language and speech assessment by 12 months of age; pre-reading assessment during preschool years; and an assessment of additional learning disabilities as well as social and emotional problems. Evidence suggests that children with 47 XXX syndrome are very responsive to early intervention services and treatment. Some services that affected children may take part in include speech therapy, occupational therapy, physical therapy, and developmental therapy and counseling.[4]

It is also recommended that infants and children with 47 XXX syndrome receive kidney and heart evaluations to detect possible abnormalities. Adolescent and adult women who have late periods, menstrual abnormalities, or fertility issues should be evaluated for primary ovarian failure (POF). Additional treatment for this disorder depends on the specific signs and symptoms present in the affected individual.[4]
Last updated: 9/24/2014

References
  1. Triple X syndrome. Genetics Home Reference. June 2014; http://ghr.nlm.nih.gov/condition/triple-x-syndrome. Accessed 9/24/2014.
  2. Triple X syndrome. Mayo Clinic. November 8, 2012; http://www.mayoclinic.org/diseases-conditions/triple-x-syndrome/basics/definition/con-20033705?p=1. Accessed 9/24/2014.
  3. Nicole R Tartaglia, Susan Howell, Ashley Sutherland, Rebecca Wilson, Lennie Wilson. A review of trisomy X (47,XXX). Orphanet Journal of Rare Diseases. May 2010; 11:5-8. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2883963/?tool=pubmed. Accessed 9/24/2014.
  4. Samango-Sprouse C. Trisomy X. National Organization for Rare Disorders (NORD). 2014; http://www.rarediseases.org/rare-disease-information/rare-diseases/byID/1024/viewAbstract. Accessed 9/24/2014.
  5. Tartaglia NR, Howell S, Sutherland A, Wilson R, Wilson L. A review of trisomy X (47,XXX). Orphanet J Rare Dis. May 2010; 11:5-8. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2883963/?tool=pubmed. Accessed 9/24/2014.


Other Names for this Disease
  • Triple X syndrome
  • Triple-X chromosome syndrome
  • Triple-X female
  • Triplo X syndrome
  • Trisomy X
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.