INS and obesity due to melanocortin 4 receptor deficiency: Other common traits among patients include severe early-onset obesity (with hyperphagic behavior) and several endocrine disorders, including growth hormone deficiency, abnormal glucose homeostasis, hypogonadotropic hypogonadism, hypocortisolism, elevated plasma proinsulin and pro-opiomelanocortin, and very low insulin levels [7].