RBP4 and type 2 diabetes mellitus: These include genes previously implicated in T2D or islet function, such as CDKN1C, GAD1, GLRA1, IL6, RBP4, and SLC2A26,18–21 (Supplementary Fig. 3a–f), suggesting the involvement of DNA methylation in the regulation of genes important for islet function and disease development.