Sonic Hedgehog (SHH) is one of the most significant genes regulating embryonic development in mammals, playing a pivotal role in cell differentiation, tissue fate determination, and regulating lateral symmetry of the embryo. The results of this research show that any mutation whether, a loss of function or a change in the regulation of gene expression in SHH gene leads to severe and highly complex consequences for embryonic development.as a result for that, severe disorders of CNS development SHH is a morphogen essential for germline formation and neuronal differentiation. Mutations in this gene result in failure to develop properly the cerebellum, cerebral cortex, and optic nerve. The holoprosencephaly (HPE) is the most prevalent form where the forebrain doesn't separate to two cerebral hemispheres, which is accompanied by gross deformity of the face and mental retardation. SHH gene controls the axial differentiation of the limbs, SHH gene mutations lead to axial limb deficiencies, also of split hand/ foot malformation, which, among other things, causes the proper placement of organs in the body and the formation of the lungs, intestines and teeth. Conclusion: the study confirms, SHH gene plays one of the major guardian roles in healthy embryonic development. Any impairment in its functioning however insignificant will upset the sensitive homeostasis of the developmental signals, and cause a vast array of malformations of the central nervous system, the skeleton, and internal organs.
Hadi et al. (2026) studied this question.