There have been a number of revisions to the diagnostic criteria for MS over the last 15 years (2001, 2005, and 2010) while the revised Wingerchuk criteria (2006) incorporates the anti-aquaporin 4 antibody (anti-AQP4 Ab) in the diagnosis of neuromyelitis optica (NMO) and its spectrum disorders (NMOSD) [4–10]. Here, AQP4 is linked to neuromyelitis optica.