Among the susceptible haplotypes in these Japanese patients with T1D, the HLA DRB1*04:05-DQB1*04:01 haplotype was more frequent in both the NIR-SPIDDM (19.2%) and IR-SPIDDM (30.6%) patients compared to the controls (12.2%). This evidence concerns the gene HLA-DRB1 and type 1 diabetes mellitus.