HLA-DRB1 and type 1 diabetes mellitus: Our results are in agreement with some of the previous studies, confirming that HLA-DRB1 is a more relevant gene of susceptibility compared to INS and PTPN22 and proved, using the BN, that the INS and PTPN22 genotypes marginally influence T1D risk in all different HLA-DRB1 genotype risk categories [29]–[31].