Hereditary angioedema (HAE) due to C1 inhibitor protein (C1-INH) deficiency was recently shown to be associated with increased risk of venous thromboembolism (VTE). This is the first national family study of HAE with the aim to determine the familial risk of VTE. The Swedish Multi-Generation Register was linked to the Swedish National Patient Register during the period 1964-2018. Only HAE patients with a validated diagnosis were included in the study and were linked to their family …