CYP27B1 and myeloid sarcoma: This hydroxylase forms part of an LD group on chromosome 12 and the major alleles of SNPs rs10877012 (G), rs10877013 (C), and rs703842 (A) (tagged by SNP rs6581155 with r2 ≥ 0.8) identify the CYP27B1 haplotype associated with an increased risk of MS (52, 107).