Obesity-induced insulin resistance is characterized by a series of events: i) impaired regulation of lipolysis in adipocytes, ii) increased circulating levels of free fatty acids [45], iii) ectopic fat storage in muscle and liver, iv) impaired ability of insulin to inhibit hepatic glucose production and muscular glucose uptake [46], v) increased beta cell death by apoptosis (glucolipotoxicity) [43,47]. The gene discussed is INS; the disease is obesity due to melanocortin 4 receptor deficiency.