Mortality has dramatically declined in recent years with routine use of high-dose steroid treatment, plasma exchange and immunosuppressants (in particular B cell-depleting agents) [1, 11], and with more and more patients surviving the first attack, NMO was found to be a relapsing disease in the vast majority of cases, especially in AQP4-IgG-seropositive patients [1]. This evidence concerns the gene AQP4 and neuromyelitis optica.