fragile X syndrome(redirected from X-linked mental retardation and macroorchidism)
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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.