X-CHROMOSOMALLY INHERITED SPLIT-HAND SPLIT-FOOT ANOMALY IN A PAKISTANI KINDRED

A Pakistani kindred comprising seven generations and 36 members with the split-hand/split-foot anomaly is described. The full expression of the trait, monodactylous or split hand and split foot, mainly of the lobster-claw type, was present in 33 males and 3 females. Other females showed a distinctly milder expression of the trait, usually in the form of partial syndactyl, metacarpal and phalangeal hypoplasia, and malformation. The distribution of the affected members in the pedigree is compatible with X-chromosomal inheritance. Hemizygous males and presumably homozygous females exhibit the typical split-hand/split-foot anomaly, whereas only a part of the obligatory heterozygous females show the milder expression. There were no associated anomalies, such as ectodermal dysplasia, cleft lip/palate, degeneration, malformations of the long bones or internal organs, and overt mental retardation.