Compared with HCs, the phenotype frequency of DRB1*04:05 was significantly higher in patients with MS in both northern and southern regions (pcorr = 0.0224 and pcorr = 0.0384, respectively) (Additional file 2: Tables S2 and S3). There was no significant difference in the distribution of DRB1 alleles between northern and southern HCs (Additional file 2: Table S4). The gene discussed is HLA-DRB1; the disease is myeloid sarcoma.