MOG and demyelinating disease: Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) is a distinct demyelinating disorder of the central nervous system (CNS) characterized by the presence of pathogenic immunoglobulin G (IgG) antibodies targeting the extracellular domain of myelin oligodendrocyte glycoprotein (MOG), a glycoprotein expressed on the surface of oligodendrocytes and the outermost lamellae of CNS myelin sheaths.