Characterizing pediatric-onset neuromyelitis optica spectrum disorder in British Columbia

Background: Neuromyelitis optica spectrum disorder (NMOSD) has emerged as a disorder distinct from multiple sclerosis, largely due to the discovery in 2004 of a novel disease marker, aquaporin-4 immunoglobulin or AQP4-IgG (also known as NMO-IgG). Differentiating NMOSD from multiple sclerosis has important prognostic and treatment implications. The features of pediatriconset multiple sclerosis have been reported previously and are known to overlap considerably with adultonset multiple sclerosis. Less is known about the presentation of pediatric-onset NMOSD. Methods: Demographic and clinical characteristics of pediatric-onset NMOSD patients in British Columbia were identified using UBC Hospital records. Data from 10 cases were collected and analyzed over 5 years. All cases were diagnosed by a neurologist with expertise in NMOSD. Results: Cases of NMOSD with AQP4-IgG (30.0%) and without AQP4-IgG (40.0%) were identified, along with cases of longitudinally extensive transverse myelitis (30.0%). A diverse ethnic population was involved in the study, which included