More recently, Xavier et al., confirmed prior findings that DNA methylation acts as a mediator of the HLA-DRB1*1501 allele and provided evidence that this occurs early in disease pathology rather than as a result of treatment or long-standing disease by using a large dataset of MS cases early in their diagnosis with age/sex/location-matched controls. The gene discussed is HLA-DRB1; the disease is myeloid sarcoma.