Approximately 40 million people take ACE inhibitors (ACEi) to treat hypertension and cardiovascular disease. A small proportion of white patients who take ACEi (0.1-0.7%) develop angioedema (AEACEI) (Israili and Hall, 1992; Vleeming et al., 1998), a potentially life-threatening side effect characterized by swelling of the face, lips, tongue, and airway that can lead to suffocation and death if severe. ACEi-associated angioedema is 4 to 5 times more prevalent among African Americans (Brown et al., 1996; Coats, 2002). Other risk factors include female sex, smoking, immunosuppressant therapy, and seasonal allergies. The pathophysiology of ACEi-associated angioedema is thought to be related to increased circulating bradykinin, which is normally degraded by ACE. During pharmacologic ACE inhibition, bradykinin is primarily degraded by aminopeptidase P (summary by Duan et al., 2005 and Woodard-Grice et al., 2010). Aminopeptidase P is encoded by 3 genes: XPNPEP1 (602443) on chromosome 10q25, XPNPEP2 (300145) on chromosome Xq25, and XPNPEP3 (613553) on chromosome 22q13. [from
OMIM]