A, ataxia; AQP4, aquaporin-4; CSF, cerebrospinal fluid; Dx, diagnosis; F, female; GC, global confusion; M, male; NMOSD, neuromyelitis optica spectrum disorder; OA; ocular abnormalities; ON, optic neuritis; UL, unilateral limb symptom; UNK, unknown; WE, Wernicke's encephalopathy; +, positive; -, negative. Here, AQP4 is linked to optic neuritis.