Non-HLA genes associated with T1D involve in the immune system cell development and differentiation, as well as various signaling pathways with altered expression rates of soluble molecules or receptors such as insulin, protein tyrosine phosphatase non-receptor type 22 (PTPN22), cytotoxic T-lymphocyte antigen 4, interleukin (IL)-10 and interleukin 2 receptor subunit alpha. Here, PTPN22 is linked to type 1 diabetes mellitus.