HLA-DRB1 and type 1 diabetes mellitus: As illustrated in Figure 2, extensive linkage disequilibrium (LD) was observed between the HLA-DRB1 and -DQB1 loci and between the HLA-B and -C loci, with higher Wn values observed between the HLA-DRB1 and -DQB1 loci in T1D individuals and higher Wn values between the HLA-B and -C loci in control individuals.