However, while the relative importance of enzymatic vs. non-enzymatic actions and the overall significance of DPP-4 for normal physiological regulation in humans and for the pathogenesis of metabolic disease are still largely unknown, targeting the catalytic activity has been harnessed pharmacologically, and DPP-4 inhibitors now play an important part in the therapy of T2DM. This evidence concerns the gene DPP4 and metabolic disease.