The detection of myelin oligodendrocyte glycoprotein (MOG) antibodies in cases of optic neuritis (ON) has recently led to the differentiation of MOG immunoglobulin G associated optic neuritis (MOG-ON) from the more common idiopathic or multiple sclerosis (MS) associated optic neuritis (MS-ON) [1, 2]. The gene discussed is MOG; the disease is optic neuritis.