AQP4 and neuromyelitis optica: The evolving epidemiology of NMO/NMOSD with an increasing prevalence in the elderly calls into question whether there is a difference between early-onset (EONMO/EONMOSD) and late-onset NMO/NMOSD (LONMO/LONMOSD) phenotypes in patients who are AQP4-seropositive, and warrants review as to whether a different treatment approach is appropriate.