One double-positive patient suffered the simultaneous occurrence of MS-like lesions, typical of those in the brains of MOG-ab-positive NMOSD individuals, along with an NMO-like lesion in the postrema area, typical of brain lesions of the AQP4-ab single-positive NMOSD group (Figure 4G). The gene discussed is AQP4; the disease is myeloid sarcoma.