ACE and early-onset autosomal dominant Alzheimer disease: Although there is concern that ACEIs may enhance brain Aβ (1–42) deposition from basic research [36] because ACE converts Aβ (1–42), which plays a causative role in the development of Alzheimer disease, to Aβ (1–40) [37], recent pilot clinical trials showed that ramipril inhibits cerebrospinal fluid (CSF) ACE activity, but did not influence CSF Aβ (1–42) and cognition [38].