Etiology

Multiple sclerosis (MS) is a leading cause of neurological disability in young adults. Although much remains to be understood about its etiology, converging evidence suggests that it is a complex disease that emerges from an abnormal autoimmune response in genetically susceptible individuals after specific environmental exposures. Association studies have identified several single nucleotide polymorphism susceptibility loci in addition to the well-established allele HLA-DRB1*1501. Proposed environmental risk factors include infections, smoking, and vitamin D deficiency. Here, we review the strongest candidate etiologic factors in MS.