Diabetes mellitus is a chronic disease characterized by elevated blood glucose levels originating from autoimmune β-cell destruction (type 1 diabetes) or a progressive loss of pancreatic function due to inadequate insulin secretion by β-cells as a consequence of insulin resistance exerted by peripheral tissues, such as the liver, muscle, and adipose tissue (type 2 diabetes). The gene discussed is INS; the disease is type 2 diabetes mellitus.