这个基因编码一种蛋白质，这种蛋白质有助于形成早期胚胎的模式它被认为是腹部神经管、前后肢轴和腹侧体节的构图中的关键诱导信号。与果蝇的sonic hedgehog蛋白具有序列和功能相似性的三种人类蛋白中，这种蛋白最为相似。蛋白质作为前体被自动催化裂解；n-末端部分可溶并包含信号活性，而c-末端部分参与前体处理。更重要的是，C-末端产物共价地将胆固醇部分附着到N-末端产物上，将N-末端产物限制在细胞表面并防止其在整个发育胚胎中自由扩散这种蛋白质或其信号通路的缺陷是无前脑（hpe）的一个原因，在这种疾病中，发育中的前脑不能正确地分为左右半球。hpe表现为面部畸形。也有人认为，该基因或其信号通路的突变可能与VACTERL综合征有关，该综合征的特征是脊椎缺损、肛门闭锁、气管食管瘘伴食管闭锁、桡肾发育不良、心脏异常和肢体畸形此外，位于该基因上游的约1兆碱基的长程增强子的突变破坏肢体构型，并可导致前轴多指畸形。[由RefSeq提供，2008年7月]
This gene encodes a protein that is instrumental in patterning the early embryo. It has been implicated as the key inductive signal in patterning of the ventral neural tube, the anterior-posterior limb axis, and the ventral somites. Of three human proteins showing sequence and functional similarity to the sonic hedgehog protein of Drosophila, this protein is the most similar. The protein is made as a precursor that is autocatalytically cleaved; the N-terminal portion is soluble and contains the signalling activity while the C-terminal portion is involved in precursor processing. More importantly, the C-terminal product covalently attaches a cholesterol moiety to the N-terminal product, restricting the N-terminal product to the cell surface and preventing it from freely diffusing throughout the developing embryo. Defects in this protein or in its signalling pathway are a cause of holoprosencephaly (HPE), a disorder in which the developing forebrain fails to correctly separate into right and left hemispheres. HPE is manifested by facial deformities. It is also thought that mutations in this gene or in its signalling pathway may be responsible for VACTERL syndrome, which is characterized by vertebral defects, anal atresia, tracheoesophageal fistula with esophageal atresia, radial and renal dysplasia, cardiac anomalies, and limb abnormalities. Additionally, mutations in a long range enhancer located approximately 1 megabase upstream of this gene disrupt limb patterning and can result in preaxial polydactyly. [provided by RefSeq, Jul 2008]