Four HLA-DR4 alleles (HLA-DRB1*04:01, *04:02, *04:04 and *04:05) increased T1D risk (i.e., susceptible) with OR04:01 = 3.64 (p = 3.19×10−64), OR04:02 = 2.55 (p = 0.025), OR04:04 = 1.58 (p = 1.91×10−3) and OR04:05 = 5.95 (p = 7.62×10−4). Here, HLA-DRB1 is linked to type 1 diabetes mellitus.