Astrocyte injury caused by AQP4-IgG is a key characteristic distinguishing NMOSD from inflammatory demyelinating CNS disorders, such as MS, where the primary target is myelin.25Several new treatments have emerged based on the molecular mechanisms of NMOSD pathophysiology, including B cell depleting therapies, complement inhibition, and blocking cytokine signaling.24 The gene discussed is AQP4; the disease is myeloid sarcoma.