IGF1 and obesity due to melanocortin 4 receptor deficiency: The human MAGEL2 has been implicated in Prader-Willi Syndrome, a genetic disorder characterized by short stature, low muscle tone, cognitive disabilities, increased food intake, obesity, low levels of insulin and insulin-like growth factor 1 (IGF1), incomplete sexual development, hypogonadism, and male infertility [21], [22].