Definition: According to the National Fragile X Foundation, "Fragile X syndrome (FXS) [is] the most common cause of inherited mental impairment. This impairment can range from learning disabilities to more severe cognitive or intellectual disabilities. (Sometimes referred to as mental retardation.) FXS is the most common known cause of autism or 'autistic-like' behaviors. Symptoms also can include characteristic physical and behavioral features and delays in speech and language development."
Fragile X is caused by an inherited genetic mutation, and a test exists to determine whether a child with autism is also diagnosable with Fragile X. The disorder occurs in 2% to 6% of all children diagnosed with autism, though about one third of children with Fragile X are autistic. Doctors recommend that all children with autism be tested for Fragile X, since the disorder does run in families.
Sources:
Families and Fragile X Syndrome. National Institute of Child Health and Human Development, NIH, DHHS. (2003). Washington, DC: U.S. Government Printing Office.
Also Known As: FXS, Fragile X
