From Wikipedia, the free encyclopedia.
''This article is about the sonic hedgehog gene and proteins. For information on the Sega game, see Sonic the Hedgehog.
Sonic hedgehog (shh) is one of three proteins in the hedgehog family, the others being desert hedgehog (dhh) and indian hedgehog (ihh).
Mutations in the human sonic hedgehog gene (SHH) cause holoprosencephaly (HPE).
