HEDGEHOGS ESCAPE FROM PANDORA BOX

The Hedgehog family of secreted glycoproteins proteins plays multifari ous roles during vertebrate embryogenesis. In both the Drosophila and vertebrate embryo correct deployment of Hedgehog-like proteins is crit ical for the generation of pattern in many tissues and organs. New evi dence now reveals that genes involved in hedgehog signalling are mutat ed in a number of common human genetic disorders, including skin cance r and craniofacial defects. The understanding of how cells generate, r eceive and transduce the Hedgehog signal during development has led to the establishment of molecular paradigms for the pathogenesis of thes e diseases. These studies clearly illustrate that knowledge of the nor mal role of a gene during development is critical for generating an un derstanding of the disease state in which it is mutated.