Polydactyly in a carrier of the gene for the Meckel syndrome.

Much of the Meckel syndrome literature has been concerned with the criteria for diagnosis but little has been said concerning heterozygote expression. We describe 3 affected brothers whose father and his paternal first cousin had postaxial polydactyly of both feet. A review of the literature was undertaken with regard to possible manifesting heterozygotes. We conclude that it is important to examine the relatives of patients with the Meckel syndrome for mild abnormalities, as these may be evidence of a manifesting heterozygote. Such information may be useful for genetic counselling.