Nearly all patients with CD and T1D carry either the DRB1*03‐DQA1*05:01‐DQB1*02:01 (DR3‐DQ2.5) or DRB1*04‐DQA1*03‐DQB1*03:02 (DR4‐DQ8) haplotypes.12, 13. The gene discussed is HLA-DRB1; the disease is type 1 diabetes mellitus.