When the relationship between HLA-DRB1, INS and PTPN22 genotypes was evaluated separately, a significant association between these genes and T1D was found (p = 0.003 for HLA, p = 0.9 *10−3 for INS gene and p = 1.5*10−5 for PTPN22). Here, PTPN22 is linked to type 1 diabetes mellitus.