Over the past 2 decades numerous effective and targeted therapies for HAE have emerged including regular prophylactic intravenous or subcutaneous donor derived or recombinant C1 INH, inhibitors of kallikrein (berotralstat, lanadelumab, and ecallantide) and the bradykinin receptor antagonist icatibant. The gene discussed is KLK4; the disease is hereditary angioedema.