The identified amino acid positions that are significantly associated with T1D on the HLA-DRB1, HLA-DQA1, and HLA-DQB1 genes, whether previously reported or novel, might have a functional impact on the three-dimensional structure of the HLA genes, including antigen binding sites, and may either cause T1D or influence the age of T1D onset. This evidence concerns the gene HLA-DQA1 and type 1 diabetes mellitus.