Hereditary angioedema (HAE) is a rare but important disease caused by a genetic deficiency or impaired function of the C1-esterase inhibitor (C1INH). C1INH is a key regulator of complement and the contact activation system. In HAE, the dysfuntional C1INH-activity results in recurrent swellings of skin and mucosal linings. In the project, we investigate genetics and co-morbidities in HAE from an epidemiological perspective. In addition, possible interference of HAE with coagulation and host defense is characterized using clinical samples. The aim is to identify novel opportunities to prevent and treat hitherto unknown co-morbidities in HAE.