NMOSD is a rare, lifelong, debilitating central nervous system autoimmune disease that primarily damages the optic nerve and spinal cord, leading to blindness, muscle weakness and paralysis. People with NMOSD experience severe, unpredictable relapses that directly lead to cumulative, permanent, neurological damage and disability. In some cases, relapse can lead to death. NMOSD affects more than 10,000 people in Europe, 15,000 people in the United States, and hundreds of thousands of people around the world. The disease is most common among non-Caucasian women in their 30s and 40s.
NMOSD is usually associated with a pathogenic antibody (AQP4-IgG), which targets and destroys a specific type of cell called astrocytes, causing inflammatory lesions of the optic nerve, spinal cord, and brain. AQP4-IgG antibodies can be detected in the sera of approximately two-thirds of NMOSD patients.