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Fragile XE syndrome

Other Names for this Disease
  • Fragile site, folic acid type
  • FRAXE syndrome
  • X-linked mental retardation associated with fragile site FRAXE
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Fragile XE syndrome is a genetic condition associated with mild to borderline intellectual disabilities (IQ = 50-85) with physical features differing from person to person. The characteristic features are learning difficulties, often a consequence of communication problems (speech delay, poor writing skills), and overactivity. Fragile XE syndrome is caused by a specific type of change (mutation) called a trinucleotide repeat expansion that occurs on chromosome X. The repeating trinucleotide in Fragile XE syndrome is CCG. When the number of CCG repeats is over 200, people typically have the signs and symptoms seen in Fragile XE syndrome.[1]

Last updated: 3/15/2010


  1. Gecz J. The FMR2 gene, FRAXE and non-specific X-linked mental retardation: clinical and molecular aspects. Ann. Hum. Genet. 2000;
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Basic Information

  • The National Center on Birth Defects and Developmental Disabilities (NCBDDD) at the Center for Disease Control and Prevention (CDC) provides information about developmental disabilities, including mental retardation.  To view this information, click on the link below.
  • Genetics Home Reference (GHR) contains information on Fragile XE syndrome. This website is maintained by the National Library of Medicine.

In Depth Information

  • The Online Mendelian Inheritance in Man (OMIM) is an catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Fragile XE syndrome. Click on the link to view a sample search on this topic.