Inflammatory demyelinating diseases are a heterogeneous group of disorders with an acute or chronic inflammatory process underlying their aetiopathogenesis, which includes multiple sclerosis (MS), neuromyelitis optica (NMO), and neuromyelitis optica spectrum disorders (NMOSD), acute disseminated encephalomyelitis (ADEM), and myelin oligodendrocyte glycoprotein antibody-associated demyelination (MOGAD) [21]. The gene discussed is OMG; the disease is neuromyelitis optica.