MOG and neuromyelitis optica: ON may present in the setting of different systemic and neurological disorders such as multiple sclerosis (MS), neuromyelitis optica spectrum disorder (NMOSD), and myelin-oligodendrocyte glycoprotein antibody-associated disease (MOGAD).[1] Early differentiation of MS, NMOSD, and MOGAD is critical, as each has a different pathophysiology that affects treatment options, clinical outcomes, and morbidities.