G6PD and neuromyelitis optica: They suggested that patients with NMO and low antioxidant status were not able to handle the toxicity of free radicals that lead to inflammation, neurodegeneration, and demyelination.22 Considering the critical role of G6PD in neutralizing oxidants, G6PD level in different areas of the CNS has been studied in different neurodegenerative diseases including Alzheimer's disease (AD) and Parkinson's disease (PD).23,24 However, no report on the level of this enzyme in patients with MS and NMO is available.