DPP4 inhibitors (Sitagliptin, Vildagliptin, Alogliptin, and Saxagliptin) have become mainstay oral hypoglycaemic therapies in type 2 diabetes mellitus based on their capacity to prevent breakdown and prolong the activity of the incretin glucagon-like peptide 1 (GLP-1). This evidence concerns the gene GCG and type 2 diabetes mellitus.