These included a history of recurrent angioedema in the absence of concomitant hives or use of medication known to cause angioedema; documented normal or near normal C4, C1-INH antigen and function; and either a F12gene mutation associated with the disease, or family history of angioedema and documented lack of efficacy of chronic high dose non-sedating antihistamine therapy [13]. Here, SERPING1 is linked to angioedema.