A genome-wide association study (GWAS) of 12,584 people with MS identified homozygous carriership of the A allele at variant rs10191329 in the DYSF-ZNF638 locus, hereafter referred to as rs10191329AA, to associate with a 3.7-year shorter median time to require a walking aid. This evidence concerns the gene ZNF638 and myeloid sarcoma.