Fragile X syndrome

Fragile X syndrome leads to developmental delays including speech delays and intellectual disability (formerly known as mental retardation) of varying degrees from severe cognitive impairment to mild learning disabilities. Individuals with fragile X syndrome can also have extreme anxiety, sensory disorders, social withdrawal, aberrant behavior, aggressive behavior, and stereotypic (repetitive and without function) behaviors like hand-flapping and body rocking. Many of these behaviors, including gaze avoidance, can cause fragile X syndrome to be mistaken for autism. While people with fragile X syndrome can also have autism, fragile X syndrome is a separate disorder with additional signs and symptoms.