On the inheritance of the split hand/split foot malformation.
Analysis of families with non-syndromal split hand/split foot (SHSF) confirms the existence of 2 distinct entities, most probably caused by at least 2 different autosomal dominant genes. In the families in which the SHSF malformation is non-syndromal and limited to the hands and feet (type I), the pattern of inheritance is of a regular autosomal dominant gene with a high penetrance (96%). In families in which at least one individual has other limb malformations and SHSF (type II), the transmission is often unusual. In most families, the gene is non-penetrant, sometimes for generations, before the birth of the first affected individual. Thereafter, among the descendants of affected individuals, the penetrance is reduced (66%), suggesting the possible existence of another gene which controls the appearance of the clinical manifestations. The possibility that SHSF associated with other limb malformations is a disorder caused by trinucleotide repeat instability is raised.
Zlotogora
J
J
Department of Human Genetics, Hadassah Medical Center, Hebrew University, Jerusalem, Israel.
D002897:Chromosomes, Human, Pair 7; D005532:Foot Deformities, Congenital / Q000235:genetics*; D015870:Gene Expression; D005799:Genes, Dominant; D018740:Genetic Heterogeneity; D006228:Hand Deformities, Congenital / Q000235:genetics*; D006801:Humans; D009030:Mosaicism; D012091:Repetitive Sequences, Nucleic Acid