Abstract
Neuromyelitis optica (NMO) is an autoimmune disease of the CNS and is characterized by typically acute and severe impairment of the optic nerve and spinal cord. Autoantibodies to aquaporin-4 (aquaporin-4 immunoglobulin G; AQP4-IgG) are serological biomarkers of this disease that are detectable in approximately 80% of patients.
The assessment of these antibodies has shown that symptoms of this immune-mediated astrocytopathy are not restricted to the optic nerve and spinal cord. Some patients can develop symptoms and signs due to brainstem, diencephalic, and cerebral involvement.
The term NMO spectrum disorders (NMOSD) was coined based on these pieces of knowledge. Epidemiological data on this disease are limited but there are some clear differences to multiple sclerosis that may be most commonly considered in the differential dia-gnosis.
The part of AQP4-IgGnegNMOSD patients might have another type of autoantibodies. These antibodies can target the myelin oligodendrocyte glycoprotein.
The characteristics of this group of patients are partially different.