If we had focused on single alleles, we would have found different risks for T1D for DQB1*02:01 (OR 12.04 (9.97; 14.5), p < 0.001) and DRB1*02:02 (no case found in our cohort, OR 0.04 (0.01; 0.15), p < 0.001), though DQB1*02:02 and 02:01 have the same amino acid sequence coded by exon 2, coding for the peptide binding motif of the beta-chain of the HLA DQ antigen. The gene discussed is HLA-DRB1; the disease is type 1 diabetes mellitus.