The effects of genetic polymorphisms in genes related to the response to DPP-4 inhibitors (DPP4, wolframin endoplasmic reticulum transmembrane glycoprotein (WFS1), and potassium voltage-gated channel subfamily J member 11 (KCNJ11)) were determined in 662 T2D patients treated with sitagliptin, vildagliptin, or linagliptin (n = 331), or with other antidiabetic medications (control group, n = 331) [38]. The gene discussed is DPP4; the disease is type 2 diabetes mellitus.