In this study, we have measured the key downstream RAS mediating enzymes (ACE-1 and ACE-2, respectively) and Ang-II levels (as a key determinant of prevailing signaling routes in counter-regulatory RAS pathways following conversion to Ang-[1–7] or Ang-III/Ang-IV) in the FCx and temporal cortex (TCx) in a cohort of normal aging and a separate AD and age-matched control cohort that was grouped according to disease stage severity: controls (Braak tangle stage 0–II), intermediate stage (Braak tangle stage III–IV), and end-stage disease (Braak tangle stage V–VI). This evidence concerns the gene ACE2 and Alzheimer disease.