DPP-4 inhibitor (Gliptin) naïve diabetic patients were subjected to scrutiny due to the success of DPP-4 inhibitors in the treatment of type 2 diabetes mellitus that leads to improved glycemic control by stimulating insulin secretion and biosynthesis, B-cell proliferation and by inhibiting glucagon release and B-cell apoptosis. This evidence concerns the gene GCG and diabetes mellitus.