Dipeptidyl peptidase IV inhibitors (DPP-4i) prevent the degradation of glucose-dependent insulinotropic polypeptide (GIP) as well as glucagon-like peptide 1 (GLP-1), and are now widely used for the treatment of the T2DM due to the low risk of hypoglycemia (11, 12). The gene discussed is GCG; the disease is type 2 diabetes mellitus.