Triphalangeal thumb–polysyndactyly syndrome and syndactyly type IV are caused by genomic duplications involving the long range, limb-specific <i>SHH</i> enhancer

Abstract

Both TPTPS and SD4 are due to duplications involving ZRS, the limb specific SHH enhancer. Point mutations in the ZRS and duplications encompassing the ZRS cause distinctive limb phenotypes.