Hereditary angioedema (HAE) with C1-inhibitor deficiency (HAE-C1INH) is a rare genetic disorder in which there exists either a deficiency of C1INH protein (HAE-C1INH type 1) or production of C1INH that is dysfunctional (HAE-C1INH type 2). The gene discussed is SERPING1; the disease is hereditary disease.