Demyelinating diseases in Asia

Purpose of review The present review aims to discuss the recent advances in inflammatory demyelinating diseases of the central nervous system in Asia. Recent findings Prevalence of multiple sclerosis (MS) in Asia is lower than that in Western countries, although it has been increasing recently. Meanwhile, there seems to be no major difference in neuromyelitis optica (NMO) prevalence in various regions or ethnicities. Thus, the ratios of NMO/NMO spectrum disorder (NMOSD) to MS are higher in Asia as compared with Western countries, indicating that the differential diagnosis between NMO/NMOSD and MS is a major challenge in Asia. Although the detection of aquaporin-4 (AQP4)-antibody is critical in distinguishing NMO/NMOSD from MS, some patients with NMO/NMOSD phenotype are seronegative for AQP4-antibody, and a fraction of those patients possess autoantibody against myelin oligodendrocyte glycoprotein. The clinical profile of Asian MS seems to be essentially similar to that in Western MS after careful exclusion of NMO/NMOSD, although some unique genetic and/or environmental factors may modify the disease in Asians. Summary MS prevalence has been low but is increasing in Asia. In contrast, NMO/NMOSD prevalence seems relatively constant in the world. Asian MS is not fundamentally different from Western MS, but some genetic and/or environmental differences may cause some features unique to Asian patients.