A COMPLEX BILATERAL POLYSYNDACTYLY DISEASE LOCUS MAPS TO CHROMOSOME 7Q36

We demonstrate that the gene responsible for a congenital limb deformi ty (polysyndactyly) maps to chromosome 7q36 in a large family. Pre- an d postaxial anomalies of the extremities are inherited in this family as an autosomal dominant trait. The disease locus is closely linked to D7S550 (maximum lod score = 6.85, theta = 0). This region is homologo us to a segment of mouse chromosome 5, where the mutations hammer toe (HM) and hemimelic extra toes (HX) have been mapped. These data sugges t that human chromosome 7q36 and the homologous region of mouse chromo some 5 contain genes involved in limb pattern formation.