In this study we report a detailed clinical analysis of 30 AQP4-seropositive NMO/LONMOSD patients ≥ 50 years old (age at onset of first symptoms) and compare the results with those of AQP4-seropositive EONMO/EONMOSD patients (age at onset of first symptoms ≤ 49 years), and we describe several novel features associated with this age group. The gene discussed is AQP4; the disease is neuromyelitis optica.