Western versus asian types of multiple sclerosis: Immunogenetically and clinically distinct disorders

The polymorphism of HLA‐DRBI, ‐DRB3, and ‐DRB5 genes as well as magnetic resonance images of the brain and spinal cord were studied in 57 Japanese patients with multiple sclerosis (MS). Twenty‐three patients clinically displayed selective involvement of the optic nerve and spinal cord and were classified as having Asian‐type MS. Patients with Asian‐type MS had fewer brain lesions shown gy magnetic resonance imaging, but more gadolinium‐enhanced spinal cord lesions than did patients with Western‐type MS (47% vs 17%). Fruthermore, the DR2‐associated DRBI1501 allele and DRB50101 allele were associated with Western‐type MS (41.2%), but not with either Asian‐type MS (0%) or healthy control subjects (14.2%). Heterogeneity inthe immunogenetic background and in the magnetic resonance imaging features between the two subtypes of MS thus suggests the presence of two etiologically distinct diseases in Asians.