Genes associated with autoimmune and inflammation‐related pathways, including CTLA4, transforming growth factor beta (TGFβ), nuclear factor kappa B (NF‐κB), p38 mitogen‐activated protein kinase, toll‐like receptor, and interleukin‐6 (IL‐6), showed increased H3K9me2 in lymphocytes from the peripheral blood of T1D patients compared to healthy controls, most likely because of the recruitment of EHMT2. Here, CTLA4 is linked to type 1 diabetes mellitus.