Aquaporin-4 deficiency reduced cytotoxic edema caused by water intoxication, cerebral ischemia, and acute bacterial meningitis; however, it intensified vascular edema caused by brain tumor, the damage to the cortex due to hypothermia, central nervous system infections, and kaolin-induced obstructive hydrocephalus [52,53]. The gene discussed is AQP4; the disease is Hydrocephalus.