AQP4 and Alzheimer disease: Supporting evidence of this has also been shown in humans; two independent single nucleotide polymorphism (SNP) variant association studies identified multiple SNPs in the Aqp4 gene that were associated with cognitive decline in Alzheimer’s disease (AD) and increased Aβ burden in humans with reduced sleep quality (Burfeind, 2017; AIBL Research Group et al., 2018).