Hedgehog’s escape from Pandora’s box

 The Hedgehog family of secreted glycoproteins proteins plays multifarious roles during vertebrate embryogenesis. In both the Drosophila and vertebrate embryo correct deployment of Hedgehog-like proteins is critical for the generation of pattern in many tissues and organs. New evidence now reveals that genes involved in hedgehog signalling are mutated in a number of common human genetic disorders, including skin cancer and craniofacial defects. The understanding of how cells generate, receive and transduce the Hedgehog signal during development has led to the establishment of molecular paradigms for the pathogenesis of these diseases. These studies clearly illustrate that knowledge of the normal role of a gene during development is critical for generating an understanding of the disease state in which it is mutated. Received: 22 May 1997 / Accepted: 21 July 1997