AQP4 and neuromyelitis optica: Although not all patients with an NMO-like presentation will be AQP4 antibody positive, the majority are, whereas those with MS are more likely to be AQP4 antibody negative.16,56,61 Current evidence suggests that once NMO and NMO spectrum disorders have been excluded, Western type MS in Asia or Latin America is not fundamentally different from typical MS in the Caucasian population, and that the MAGNIMS MRI criteria would apply for such patients, although confirmatory studies should be done.