Beside MS, ADS in children under 18 years of age may also include anti-aquaporin-4-associated neuromyelitis optica spectrum disorder (AQP4-NMOSD), myelin oligodendrocyte glycoprotein antibody-associated disorder (MOGAD), or acute disseminated encephalomyelitis (ADEM) with encephalopathy (10). The gene discussed is AQP4; the disease is myeloid sarcoma.