Astrocytes are an important source of inflammatory cytokines in AD [29] and AQP4 deletion impairs release of proinflammatory cytokines by astrocytes [30, 31], suggesting that the failure of microglial accumulation around plaques in Aqp4 deficient AD mice might be a consequence of impaired astrocyte cytokine release. The gene discussed is AQP4; the disease is Alzheimer disease.