Neuromyelitis Optica is an inflammatory autoimmune disease causing demyelination of the central nervous system with degradation of the insulating sheath of at least one optical nerve (Neuritis nervi optici) and at the same time or few months later the spinal cord (Myelitis). Antibodies against aquaporin-4 are detectable in 60% to 90% of patients. In 7.4% of cases, however, antibodies against MOG are also produced. In patient who are anti aquaporin-4 negative, MOG antibodies occur in 21.1% of sera.