Fragile X syndrome and associated disorders in adulthood

Although fragile X syndrome is typically considered a pediatric developmental disorder, many manifestations persist or develop in adulthood. Manifestations depend on the length of the CGG repeat at the front end of the FMR1 gene. Patients with the premutation (55 to 200 repeats) have typically normal cognitive abilities. With increasing age, however, consequences of RNA toxicity, including primary ovarian insufficiency, the fragile X-associated tremor ataxia syndrome, fibromyalgia, hypothyroidism, neuropathy, and psychiatric problems including anxiety and depression, may develop. Patients with the full mutation (greater than 200 CGG repeats) have significant cognitive impairment ranging from learning disabilities, particularly in girls, to severe intellectual disability and autism in males. Medical problems are usually related to connective-tissue abnormalities, seizures, or psychiatric problems, including mood instability, anxiety, and/or aggression.