In summary, genetic studies in the past found over 50 associated regions; however, most associated variants (except HLA, PTPN22, IFIH1, CTSH, TYK2, and FUT2) are involved in gene regulation and only HLA-II, INS, and PTPN22 show substantial effects on T1D. The gene discussed is PTPN22; the disease is type 1 diabetes mellitus.