Since I do not have a scientific background it is difficult for me to fully understand, or really understand at all, what exactly Sonic Hedgehog is or does. For this reason I will simply regurgitate what I read online and hope it is accurate and makes sense. Sonic Hedgehog is a protein that is essential for embryonic development and is important for the development of the brain, spinal cord, eyes, limbs and other parts of the body. For example, Sonic Hedgehog is instrumental in causing the ‘eye field’, the single structure made up of the cells that develop into eyes located in the centre of the developing face, to split into two distinct eyes. If there are mutations in the SHH gene, the ‘instructions’ of which make the Sonic Hedgehog protein, not enough Sonic Hedgehog may be created and a condition called nonsyndromic holoprosencephaly can take place. If this happens the brain will not separate into two hemispheres and the eyes will not properly separate. Also of note is the fact that the protein is called Sonic Hedgehog, Sonic the Hedgehog being a well-known video game character created by SEGA.