We conducted further investigations to rule out the possibility of auto-immune encephalitis, which included anti-neuromyelitis optica (anti-NMO), aquaporin 4, anti-myelin oligodendrocyte glycoprotein (anti-MOG), fungal culture, cryptococcus-GeneXpert MTB, and Mycobacterium tuberculosis complex real-time polymerase chain reaction (PCR). The gene discussed is AQP4; the disease is neuromyelitis optica.