Sonic Hedgehog Gene

The vertebrate homologue of hedgehog, a Drosophilia—fruitfly—gene that ensures correct embryonic development. SHH products form a molecular gradient which determines which cells will emerge from the CNS during development. Toxins interfering with cholesterol metabolism in vertebrate embryos may cause cyclopia/holoprosencephaly. SHH is mutated in foetuses with holoprosencephaly type 3