Fragile X Syndrome
National Organization for Rare Disorders, Inc.
It is possible that the main title of the report Fragile X Syndrome is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.
- fragile site, folic acid type, rare, Fra(X)(Q27.3)
- fragile X mental retardation protein, FMRP
- fragile X mental retardation syndrome
- marker X syndrome
- Martin-Bell syndrome
- mental retardation, X-linked, associated with Mar Xq28
- X-linked mental retardation and macroorchidism
Fragile X syndrome is characterized by moderate intellectual disability in affected males and mild intellectual disability in affected females. Distinctive physical features are sometimes present in affected males including a large head, long face, prominent forehead and chin, protruding ears, loose joints and large testes, but these features develop over time and may not be obvious until puberty. Motor and language delays are usually present but also become more apparent over time. Behavioral abnormalities including autistic behaviors are common.
Fragile X syndrome is caused by an abnormality (mutation) in the FMR1 gene. Affected individuals have an increased number of copies of a portion of the gene called CGG repeats. The greater the number of copies of CGG, the more likely there will be increased severity of the disorder. Fragile X syndrome occurs more often in males and results in more severe disease in males.
Mutations in the FMR1 gene are associated with two other conditions in addition to the fragile X syndrome (FXTAS and POI) and these conditions have been termed FMR1-Related Disorders. (See the Related Disorders section of this report for brief summaries of the other disorders.)
1825 K Street NW, Suite 1200
Washington, DC 20006
FRAXA Research Foundation
10 Prince Place
Newburyport, MA 01950
National Fragile X Foundation
1615 Bonanza St
Walnut Creek, CA 94596
New York State Office for People with Developmental Disabilities
44 Holland Avenue
Albany, NY 12229
NIH/National Institute on Aging
31 Center Drive, MSC 2292
Bethesda, MD 20892
NIH/National Institute of Child Health and Human Development
31 Center Dr
Building 31, Room 2A32
Bethesda, MD 20892
New Horizons Un-Limited, Inc.
811 East Wisconsin Ave
P.O. Box 510034
Milwaukee, WI 53203
Genetic and Rare Diseases (GARD) Information Center
PO Box 8126
Gaithersburg, MD 20898-8126
PO Box 241956
Los Angeles, CA 90024
Let Them Hear Foundation
1900 University Avenue, Suite 101
East Palo Alto, CA 94303
Fragile X Society
Road End House
6 Stortford Road
Essex, CM6 1DA
Medical Home Portal
Dept. of Pediatrics
University of Utah
P.O. Box 581289
Salt Lake City, UT 84158
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This is an abstract of a report from the National Organization for Rare Disorders (NORD). A copy of the complete report can be downloaded free from the NORD website for registered users. The complete report contains additional information including symptoms, causes, affected population, related disorders, standard and investigational therapies (if available), and references from medical literature. For a full-text version of this topic, go to www.rarediseases.org and click on Rare Disease Database under "Rare Disease Information".
The information provided in this report is not intended for diagnostic purposes. It is provided for informational purposes only. NORD recommends that affected individuals seek the advice or counsel of their own personal physicians.
It is possible that the title of this topic is not the name you selected. Please check the Synonyms listing to find the alternate name(s) and Disorder Subdivision(s) covered by this report
This disease entry is based upon medical information available through the date at the end of the topic. Since NORD's resources are limited, it is not possible to keep every entry in the Rare Disease Database completely current and accurate. Please check with the agencies listed in the Resources section for the most current information about this disorder.
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Last Updated: 8/25/2010
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