INS and obesity due to melanocortin 4 receptor deficiency: However, given the complex and multifactorial nature of obesity (47), the familial predisposition is likely to represent a mixture of inheritance of low- to moderate-risk susceptibility genes [there is good evidence that energy homeostasis and thermogenesis, adipogenesis, leptin-insulin signaling, and hormonal signaling genes contribute to the development of obesity (48, 49)] and exposure to a common “obesogenic environment”, which is prominent in Arab countries (50).