A significant increase in AQP1, normally expressed in the choroid plexus, has been identified in astrocytes of the frontal cortex and temporal lobes in sporadic and familial AD cases, where AQP1+ astrocytes were found close to Aβ42 or Aβ40 deposits (Hoshi et al., 2012, Pérez et al., 2007). Here, AQP1 is linked to Alzheimer disease.