In the past few years, a plethora of publications has reported on serum antibodies to myelin oligodendrocyte glycoprotein (MOG) in a subset of adult patients with an NMOSD phenotype (with optic neuritis being the most frequent clinical manifestation) and beyond (involvement of cranial and peripheral nerves and encephalopathy with seizures have been reported) using highly specific immunoassays (265–275). This evidence concerns the gene MOG and optic neuritis.