SHH gene – Genetics Home Reference – NIH

Sonic Hedgehog plays a role in cell growth, cell specialization, and the normal shaping (patterning) of the body. This protein is important for development of the brain and spinal cord (central nervous system), eyes, limbs, and many other parts of the body. Sonic Hedgehog is necessary for the development of the front part of the brain (forebrain).

https://ghr.nlm.nih.gov/gene/SHH