HLA-DRB1 and type 1 diabetes mellitus: Early-onset T1D was strongly associated with the highest-risk haplotype combination HLA-DRB1*03:01-DQA1*05:01-DQB1*02:01/DRB1*04-DQA1*03:01-DQB1*03:02, affecting 44.6% of the patients in our early-onset cohort.