Definition of fragile X syndrome in US English:

fragile X syndrome


  • An inherited condition characterized by an X chromosome that is abnormally susceptible to damage, especially by folic acid deficiency. Affected individuals tend to have limited intellectual functions.

    • ‘Carrier testing is also instigated by a positive family history such as Duchenne muscular dystrophy, fragile X syndrome, or certain chromosomal disorders.’
    • ‘Such conditions include fragile X syndrome, neurofibromatosis, tuberous sclerosis, Noonan's syndrome and Cornelia de Lange's syndrome.’
    • ‘Five years earlier, the man's five-year-old grandson had been diagnosed with fragile X syndrome.’
    • ‘My siblings are affected by fragile X syndrome, a condition that causes their mental retardation and makes them hypersensitive to sounds and touch.’
    • ‘In addition, an increased frequency of occurrence is noted in patients with genetic conditions such as fragile X syndrome and tuberous sclerosis.’