In these studies, researchers identified the promoters of the insulin gene (INS)27; pancreatic and duodenal homeobox 1 (PDX1)28, which encodes a transcription factor important for both pancreatic development29 and the function of mature β-cells30; PPARG coactivator 1 alpha (PPARGC1A)31; and glucagon-like peptide 1 receptor (GLP1R)32, which stimulates insulin secretion and protects β-cell proliferation, as hypermethylated in islets from donors with T2D compared with those in islets from nondiabetic donors33. This evidence concerns the gene INS and type 2 diabetes mellitus.