In AQP4 null /APP/PS1 mice, there is a decline in cognitive performance, together with increased Aβ deposition and cerebral amyloid angiopathy, when compared to APP/PS1mice [44], most likely as a result of a failure to clear soluble Aβ along the intramural peri/paravascular drainage pathways of the blood vessels [45,46]. This evidence concerns the gene APP and cerebral amyloid angiopathy.