Neuromyelitis Optica (NMO) or Devic’s disease is an inflammatory central nervous system (CNS) disorder char-acterised by the presence of three or more vertebral segments longitudinally extensive transverse myelitis (LETM) and serum antibodies against water channel aquaporin-4 (AQP4-immunoglobulin G [IgG]).1,2 The term NMO spectrum disorder (NMOSD) was introduced in 2007 for AQP-4IgG seropositive patients with limited forms of NMO who were at risk of recurrence. The gene discussed is AQP4; the disease is transverse myelitis.