fragile X syndrome(redirected from Fragile x chromosome)
Also found in: Dictionary, Medical.
fragile X syndrome[‚fraj·əl ′eks ‚sin‚drōm]
A hereditary condition resulting from a trinucleotide repeat at an inherited fragile site on the long arm of the X chromosome. Affected males usually have some characteristic facial features, enlarged testes, and mental retardation. Females with on fragile X chromosome and one normal X chromosome may have a lesser degree of mental retardation.