Due to metabolic syndrome being a combination of disorders that involves changes in sensitivity to insulin and by extension, the action of the IR, it is perhaps not surprising that alterations in the activity of the IR have been correlated with several pathologies including hypertension, type 2 diabetes mellitus, and obesity [2,9], in addition to cardiovascular disease and diseases of the gastrointestinal (GI) tract. The gene discussed is INS; the disease is obesity due to melanocortin 4 receptor deficiency.