The term “MOGAD” encompasses a series of demyelinating diseases of the CNS characterized by optic neuritis, optic neuromyelitis, myelitis, brain/brainstem syndrome or acute disseminating encephalomyelitis (ADEM) together with the presence of anti-MOG IgG antibodies in serum [177,178]. The gene discussed is MOG; the disease is acute disseminated encephalomyelitis.