HLA-DRB1 and type 1 diabetes mellitus: The increase of DRB4*01:03:01 on DRB1*04:01 haplotypes in DRB1*04:01/*04:01 T1D w/CD case subjects versus DRB1*03:01/DRB1*04:01 case subjects and control subjects could reflect linkage of disequilibrium (LD) with alleles at other high‐risk loci.