HLA-DRB1 and myeloid sarcoma: Genome-wide association studies (GWAS) have confirmed the association of more than 200 loci of genome-wide significance with the risk of developing MS, which can explain almost half of its heritability [1,2], but for most of them, the odds ratio (OR) is somewhat modest (1.05 to 1.20), and only HLA (in particular the HLA-DRB1*15:01 haplotype) has shown a strong association with MS risk [1].