These HAE patients have normal C1-INH levels, and some of them have mutations in factor XII [5], angiopoietin-1 [6], plasminogen [7], kininogen [8], myoferlin [9], or heparan sulfate-glucosamine 3-O-sulfotransferase 6 [10]. This evidence concerns the gene SERPING1 and hereditary angioedema.