Extensive polymorphism and linkage disequilibrium (LD) complicates the efforts to precisely map associations with MS in this region but most evidence has pointed to the class II region and the HLA-DRB1(GeneID: 3123) and -DQB1 genes, and specifically to the haplotype DRB1*1501,DRB5*0101,DQA1*0102,DQB1*0602[3]. The gene discussed is HLA-DRB1; the disease is myeloid sarcoma.