While the relationship of haplogroup U with MS might be driven by the variants in its background, other non-haplogroup-associated variants [32], and genetic susceptibility factors such as haplotype HLA-DRB1*15:01~HLA-DQ*06:01 [62, 63], as well as nuclear genes and environmental factors involved in the etiology of MS may also play a role in predisposing individuals to the risk of MS. Here, HLA-DRB1 is linked to myeloid sarcoma.