Aquaporin-4 Antibodies and Neuromyelitis Optica Disease Activity

Neuromyelitis optica (NMO) is a disorder characterized by optic neuritis and by transverse myelitis that is accompanied by spinal cord lesions exceeding three vertebral segments in length. Presence of an immunoglobin G (IgG) antibody that targets epitopes on the extracellular domain of aquaporin-4 (AQP4) is a specific finding in NMO. However, whether finding AQP4 autoantibodies is simply a marker of or actually …