All three affected female subjects also had at least one copy of the A allele at the SNP rs3788853 locus, located 5' of XPNPEP2, which codes for membrane-bound APP, and is associated with decreased APP activity, decreased bradykinin and des-Arg9-BK degradation, and angioedema induced by ACE inhibitors [20,21]. Here, XPNPEP2 is linked to angioedema.