Brachydactyly type C is an autosomal dominant disorder characterized by abnormal segmentation of the index and middle fingers segregating with a high degree of variable expression in members of the same family. We have followed up and studied members of the large kindred segregating with the brachydactyly type C phenotype described by Virgil Haws in 1963, and using genetic linkage analysis, we localized the susceptibility gene to human chromosome 12q24.