HLA-C and myeloid sarcoma: Since 1970s, the knowledge of MS genetic architecture has extraordinarily advanced and several GWAS have been performed, identifying hundreds of additional MS genetic risk variants outside the MHC locus (The International Multiple Sclerosis Genetics Consortium et al., 2007; Bahlo et al., 2009; Baranzini et al., 2009; Sanna et al., 2010; Patsopoulos et al., 2011, 2019; Sawcer et al., 2011; Beecham et al., 2013).