HLA-DRB1 and myeloid sarcoma: Because many of the 48 SNPs associated with MS susceptibility in the HLA-DRB1*15:01(-) dataset are in moderate to strong LD with each other a clustering algorithm was used to group the 48 SNPs into 20 clusters (LD-R2≥.05) and identify SNPs that tagged each cluster (Table S5) [15].