SERPING1 and hereditary angioedema: While HAE type 1 and type 2 are associated with C1-INH-encoding SERPING1 mutations, type 3 HAE is not associated with these mutations and, by analyses of unrelated cases, F12 encoding coagulation Factor XII (20), and more recently, mutations in PLG encoding Plasminogen (21) and ANGPT1 encoding angiopoietin-1 (22) have been reportedly identified.