Lower ACE-2 activity in AD may therefore promote the early deposition of Aβ43 and prevent downstream cleavage of Aβ42 by ACE-1.Together, these data suggest a putative protective role of the ACE-2/Ang (1–7)/Mas pathway, not only against the development of pathology but also against the decline in cognitive function, that is lost in AD. This evidence concerns the gene ACE2 and Alzheimer disease.