Late-onset neuromyelitis optica spectrum disorder: A case series from Iran.

Abstract Introduction Neuromyelitis optica spectrum disorder (NMOSD) is a disabling autoimmune disease of the central nervous system that can start at ages of 50 or more, when it is called late-onset NMOSD (LO-NMOSD). Data on this disorder are sparse. In this cross-sectional study, patient characteristics of the disease were studied. LO-NMOSD patients of a tertiary center in Tehran were studied from 2016 to 2020. Case reports Eight patients were identified, half of whom were men. The diagnostic delay was from no time-lapse to three years (mean: 0.62, SD: 1.06), which was significantly shorter than in early-onset patients. Seven patients (87.5%) tested positive for AQP4-IgG which was significantly higher compared to early-onset patients (p-value =  0.01). Four patients (50%) had both transverse myelitis and optic neuritis as presenting symptoms, while three (38%) had just myelitis and only one (12%) had optic neuritis. Conclusion There is discrepancy regarding different aspects of LO-NMOSD. Further studies are needed to clarify the subject in order to enhance diagnosis and treatment.