Some principal mutations were identified in the molecules of factor XII (F12), plasminogen (PLG), angiopoietin 1 (ANGPT1), and kininogen 1 (KNG1) genes.4, 5, 6, 7 Furthermore, the patients with HAE without previously reported gene mutations were categorized (HAE-unknown).8 The gene discussed is KNG1; the disease is hereditary angioedema.