HLA-DQA1 and type 1 diabetes mellitus: DRB1 (associated with an increased incidence of rheumatoid arthritis) × 1401, DQB1 (associated with an increased risk of developing type 1 diabetes) × 0503, DQA1 (provides instruction for making a protein that plays a critical role in the immune system) × 0101 = 0104 and DQA1 × 05 were significantly increased in the centenarians.