Clinical testing for antibodies to myelin oligodendrocyte glycoprotein (MOG) is increasingly done in the workup of suspected immune-mediated inflammatory demyelinating disorders of the central nervous system, given the phenotypic overlap of MOG antibody-associated disease (MOGAD) with neuromyelitis optica (NMO) spectrum disorders and multiple sclerosis (MS). This evidence concerns the gene MOG and myeloid sarcoma.