HAE can be of multiple types including; type I (85% of cases) and type II HAE (14% of cases), which are generally associated with mutations in the C1INH gene, while HAE with normal C1INH (~ 1% of cases) is idiopathic and not associated with deficiency in levels or function of C1INH, however may be associated with mutations in the FXII gene27–30. The gene discussed is SERPING1; the disease is hereditary angioedema.