Perhaps known alterations in AQP4 distribution and abundance in AD (Zeppenfeld et al., 2017; Boespflug et al., 2018; Simon et al., 2018) drive increased interstitial fluid stagnation, decreasing glymphatic function past what is expected in natural aging (Kress et al., 2014). The gene discussed is AQP4; the disease is Alzheimer disease.