Novel advances in the diagnosis and treatment of neuromyelitis optica: is there a need to redefine the gold standard? 
Neuromyelitis optica (NMO) is an inflammatory disease of the central nervous system characterized by severe attacks of optic neuritis and myelitis and, unlike multiple sclerosis, was initially thought to spare the brain in the early stages.  The term NMO spectrum disorder (NMOSD) was recently used to qualify restricted forms of the disorder, which include recurrent optic neuritis, relapsing transverse myelitis and some encephalitic/brainstem presentations associated with positive aquaporin4 antibodies.  It was also recently found that other immunological targets such as myelin oligodendrocyte glycoprotein (MOG) may be associated with seronegative NMO patients.  In the present study, we detail the moving concept of NMOSD from the recent years and propose some therapeutic strategies that are clearly different compared with multiple sclerosis treatment.