HLA-DRB1 and type 1 diabetes mellitus: HLA haplotypes known to confer risk of developing T1D in the Japanese and Korean populations include DRB1*04:05-DQB1*04:01 (DR4-DQ4) and DRB1*09:01-DQB1*03:03 (DR9-DQ3); notably, a homozygous DR9-DQ3 haplotype revealed stronger susceptibility to T1D than a DR4-DQ4 haplotype (22).