Hereditary angioedema (HAE) is an autosomal dominant group of disorders that are determined by several gene variants proven or postulated to be permissive for bradykinin (BK) production, and possibly repressive for its degradation, with ensuing action on the endothelial BK B2 receptors and localized edema of subcutaneous and submucosal tissues (1, 2). The gene discussed is KNG1; the disease is hereditary angioedema.