Although various guidelines propose different treatment targets, there is consensus about the individualization of the glycemic targets [4]. While newer classes of antidiabetic agents, including sodium-glucose cotransporter-2 (SGLT2) inhibitors and GLP-1 receptor agonists, have evolved as second-line therapy in current T2DM treatment algorithms, DPP-4 inhibitors, particularly sitagliptin, continue to play a significant role in T2DM management as a safe class of oral antidiabetic agent with great clinical experience of their use. The gene discussed is DPP4; the disease is type 2 diabetes mellitus.