There is a wide variety of medications available for the treatment of T2DM, including, but not limited to, biguanides, sulfonylureas, alpha-glucosidase inhibitors, insulin sensitizers, glucagon-like peptide-1 (GLP-1) receptor agonists, and dipeptidyl peptidase-4 (DPP-4) inhibitors [17,18]. This evidence concerns the gene DPP4 and type 2 diabetes mellitus.