Fragile X syndrome

Fragile X syndrome, also known as Martin-Bell syndrome, is an uncommon inherited disorder, which is caused by abnormalities with the FMR1 (fragile X mental retardation 1) gene on the X chromosome. The condition is much more common in boys because they only have one X chromosome, while girls have two X chromosomes so there is a spare one if one is faulty. Statistics suggest that Fragile X syndrome affects 1 in 3,600 boys and 1 in 6,000 girls.

The principal symptom of Fragile X syndrome is a degree of mental impairment; the syndrome affects people in different ways and some people have much more severe symptoms than others; the gravity of the condition is determined by the degree of irregularity in the gene. Those who are more severely affected will often develop learning difficulties, which are caused by below-average intelligence. Other common symptoms of Fragile X syndrome include behavioural problems, mood swings, anxiety and hyperactivity. There is no cure for Fragile X syndrome but treatments can be used to encourage development, promote learning and support people with behavioural problems.