MetS is growing in prevalence due to an increased pervasiveness of obesity and IR, and it specifically includes the following aspects: (a) insulin targets tissues resistant to insulin-stimulated glucose consumption and reduced glucose tolerance; (b) obesity, especially central obesity, which can cause IR and hyperinsulinemia; and (c) elevated low-density lipoprotein (LDL) and triglycerides (TG), with a concomitant decrease in high-density lipoprotein (HDL) [5,6,7,8]. The gene discussed is INS; the disease is obesity due to melanocortin 4 receptor deficiency.