Although angiotensin-converting enzyme (ACE) was shown to be capable of Aβ cleavage (Hemming and Selkoe, 2005) mostly acting as a carboxydipeptidase and converting the more hydrophobic and toxic Aβ42 to Aβ40 (Zou et al., 2007), its role in AD pathology is still not clear. This evidence concerns the gene ACE and Alzheimer disease.