SERPING1 and acquired angioedema: Bradykinin-mediated angioedema includes hereditary angioedema (HAE), which is usually caused by deficient quantity or function of C1-esterase inhibitor (C1-INH), acquired angioedema where the levels of C1-INH are low due to increased consumption, and medication-associated increases in bradykinin including angiotensin-converting enzyme (ACE) inhibitors.1