Initial studies analyzed DNA methylation of candidate genes for T2DM such as INS (encoding insulin), PDX1, PPARGC1A (encoding PGC1α), and GLP1R (encoding the GLP-1 receptor) in human pancreatic islets from donors with T2DM and non-diabetic controls (Ling and Rönn, 2019). Here, PPARGC1A is linked to type 2 diabetes mellitus.