During an episode of BK-mediated angioedema, BK is overproduced by the uncontrolled activation of the kallikrein-kinin system (KKS) due to C1-inhibitor (C1-INH) deficiency [10], or is elevated due to reduced breakdown caused by angiotensin converting enzyme inhibitors (ACEIs) [11, 12]. This evidence concerns the gene SERPING1 and angioedema.