HLA-DRB1 and type 1 diabetes mellitus: The alleles that confer the greatest susceptibility and protection for Type 1 diabetes at the HLA-DRB1 locus, 03:01 and 03:02, respectively, differ at four exon 2-encoded amino acids, positions 26, 28, 47 and 86 with HLA-DRB1*03:02 encoding phenylalanine, glutamic acid, tyrosine and glycine, respectively, while HLA-DRB1*03:01 encodes tyrosine, aspartic acid, phenylalanine and valine, respectively.