OPRD1 and type 2 diabetes mellitus: T2D-associated methylation sites of e.g. BEST3, CABLES1, CDKN1A, CDKN2B, DNMT3A, FOXP1, GLP1R, HDAC7, INS-IGF2, KCNJ11, OPRD1, and PDX1 overlap active promoters, whereas methylation sites of HDAC4, HDAC7, INS-IGF2, MEG3, PDX1-AS1, SLC2A2, SYT13, and THADA overlap active enhancers (Supplementary Data 12).