Our findings also indicate that NMO is an “AQP4-opathy” with pathological targets beyond the astrocyte and provide insight into recent reports of edema [12, 20, 27, 42, 64] and hydrocephalus [6] in NMO patients that may suggest a unique model for CSF flow-dependent pathogenic events in this disease. This evidence concerns the gene AQP4 and neuromyelitis optica.