title: Frequency of fragile X chromosome in normal females.
abstract: Because of the ambiguities in diagnosing carriers of the fragile X syndrome, we studied thirty-six normal females to determine whether the fragile site at Xq27 can be seen in noncarrier females and at what frequency. A fragile site at Xq27 was identified in one out of thirty-six females, occurring at a frequency of 0.5% in her peripheral lymphocytes. We conclude that the fragile Xq27 site occurs only rarely in noncarrier females and that each laboratory should determine its own baseline frequencies of fragile X in order to most accurately distinguish between normal and carrier women.
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D005600:Fragile X Syndrome / Q000453:epidemiology*; D006801:Humans; D008875:Middle Aged; D012729:Sex Chromosome Aberrations / Q000453:epidemiology*