In an initial candidate gene study, Yang et al. compared islets from T2D (n = 9) and non-diabetic (n = 48) individuals, revealing increased DNA methylation at the insulin (INS) promoter of four specific CpG sites located 234, 180 and 102 bp upstream and 63 bp downstream of the transcription start site (TSS) [100]. The gene discussed is INS; the disease is type 2 diabetes mellitus.