Fragile X Syndrome

Living reference work entry


Fragile X syndrome is the most common form of heritable intellectual disability, affecting approximately 1 in 1,250 males and 1 in 2,000 females (Webb 1989). The prevalence appears to be 1 in 4,000–6,000 males and 1 in 8,000–10,000 females. Martin and Bell first documented X-linked mental retardation in 1943. Subsequent identification of a fragile site on the long arm of the X chromosome (Lubs 1969), discovery of cell culture medium-dependent fragile site, and recognition of a unique constellation of physical features served to distinguish fragile X syndrome from other X-linked mental retardation syndromes.


Mental Retardation Female Fetus Repeat Size Full Mutation Premutation Carrier 
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Copyright information

© Springer Science+Business Media New York 2016

Authors and Affiliations

  1. 1.Medical GeneticsShriners Hospitals for ChildrenShreveportUSA
  2. 2.Perinatal and Clinical Genetics, Department of PediatricsLSU Health Sciences CenterShreveportUSA

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