Additional Information

Fragile X Syndrome is a trinucleotide expansion repeat disorder characterized by moderate intellectual disability and subtle dysmorphic features in affected males and variable symptoms in affected females. Affected individuals have an abnormal expansion of a CGG repeat tract in the 5’-unstranslated region of the FMR1 gene on the X chromosome (>200 CGG repeats, i.e. a full mutation). Males with CGG repeats in the premutation range (55-200) have increased risk for Fragile X Tremor/Ataxia Syndrome (FXTAS). Females with a premutation have an increased risk for Primary Ovarian Insufficiency (POI).