Editing Angiotensin-converting enzyme (section)

== Genetics ==
The ACE gene, ''ACE'', encodes two [[isozyme]]s. The somatic isozyme is expressed in many tissues, mainly in the lung, including vascular [[endothelium|endothelial]] cells, epithelial [[kidney]] cells, and [[testicle|testicular]] [[Leydig cell]]s, whereas the germinal is expressed only in [[Spermatozoon|sperm]]. Brain tissue has ACE enzyme, which takes part in local [[Renin–angiotensin system|RAS]] and converts Aβ42 (which aggregates into plaques) to Aβ40 (which is thought to be less toxic) forms of [[beta amyloid]]. The latter is predominantly a function of N domain portion on the ACE enzyme. ACE inhibitors that cross the blood–brain barrier and have preferentially selected N-terminal activity may therefore cause accumulation of Aβ42 and progression of dementia.{{citation needed|date=April 2012}}