Neuromyelitis optica spectrum disorder (NMOSD) is a central nervous system autoimmune disease that preferentially targets the optic nerves and spinal cord and has a clear female preponderance, with female to male ratios ranging from 3:1 to 9:1 in aquaporin 4 antibody (AQP4-ab) seropositive patients [1]. This evidence concerns the gene AQP4 and neuromyelitis optica.