A hand-foot malformation with characteristics of triphalangeal thumbs and pre and postaxial polydactyly, isolated syndactyly or complex polysyndactyly. It has been described in some large pedigrees. Clinical presentation is variable within families, ranging from mild to severe. Malformations of the feet are usually less severe than those of the hands. Caused by duplication encompassing the limb-specific regulatory element (ZRS) of sonic hedgehog SHH, which lies in intron 5 of the limb region 1 homolog gene, LMBR1 (7q36). This syndrome is transmitted in an autosomal dominant manner with complete penetrance and variable expression.