DNA methylation was identified at the TCF7L2, KCNQ1, THADA, FTO, IRS1, and PPARG loci in islets from T2D donors [33], and some of them were associated with altered expressions of mRNA, implying that illness development is linked to a change in transcriptional activity [33]. This evidence concerns the gene TCF7L2 and type 2 diabetes mellitus.