SHC1 and obesity due to melanocortin 4 receptor deficiency: Interestingly, this region also contains SHC1 (Src homology 2 domain containing – transforming protein 1) which has been reported as having a role in human obesity[75], and as being one of the mediators for regulating the insulin-like growth factor 1 (IGF-1) pathway, which plays a key role in regulating cell proliferation, differentiation and apoptosis[76].