By considering anti-NMO antibody as a specific marker of NMOSD, brain regions with high expression of aquaporin 4 should be sought.20 It is an important point which is mentioned in the study of Marignier, et al. that found brain lesions in aquaporine-4 high expression areas including; periaqueductal grey matter, hypothalamic area, and area postrema. This evidence concerns the gene AQP4 and neuromyelitis optica.