One is NMO [1, 2] which is characterized by lesions confined to the optic nerve and spinal cord, especially, longitudinally extensive spinal cord lesions [3], positive aquaporin-4 (AQP4) autoantibody seropositivity [4], and the astrocytic impairment associated with the loss of AQP4 in the NMO lesions [5]. This evidence concerns the gene AQP4 and neuromyelitis optica.