Using genome-wide association studies (GWAS), single nucleotide polymorphisms (SNPs) and gene variants conferring risk for T1D have been identified in multiple sites including the interferon induced with helicase C domain 1 (IFIH1), HLA class II, CTLA-4, insulin, and PTPN22 genes (5–7). Here, CTLA4 is linked to type 1 diabetes mellitus.