HLA-DRB1 and type 1 diabetes mellitus: Like type 1 diabetes, the strongest genetic risk factors for LADA are variation in the MHC class II genes HLA-DQB1 and HLA-DRB1; and the highest risk is conferred by the HLA haplotypes HLA-DRB1*04-DQB1*0302 (“DR4”) and HLA-DRB1*0301-DQB1*0201 (“DR3”) (6).