The fragile X chromosome in a large Indian kindred

Abstract

A large Indian kindred in which the fragile X chromosome is segregating was investigated in Cape Town, South Africa. Eight male hemizygotes and 4 female heterozygotes were mentally retarded. There is suggestive evidence that one deceased male of reportedly normal intelligence may have been a hemizygote. The existence of the fragile X syndrome in a number of different ethnic groups supports the contention that the gene controlling the phenotype and the fragile site are the same, or at least overlap.