Sonic Hedgehog Protein (SHH, VHH-1) belongs to the hedgehog protein family which includes Indian Hh, and Desert Hh. The Hh family is involved in cell fate and patterning during embryonic development, homeostasis, and adult tissue renewal . Similar to other member in the family, SHH binds to the patched (PTC) cell surface receptor, releasing the signal transducer Smoothened (Smo) to transmit the Hh signal into the cell and activate transcription of the target gene . Precursor SHH is autocatalytically cleaved into two subunits, N-terminal and C-terminal products. Soluble N-terminal product is involved in signaling activity, while C-product displays an autoproteolysis activity on the precursor and a cholesterol transferase activity on the N-terminal product. C-terminal product attaches a cholesterol moiety to the N-terminal product, preventing N-terminal product diffusion within the developing embryo . A defect in SHH has been linked in holoprosencephaly type 3 (HPE3), in which the developing forebrain fails to separate into right and left hemispheres, and ocular coloboma .