Hereditary angioedema due to C1 inhibitor deficiency (HAE-C1INH Type 1 and Type 2) is a rare (prevalence 1:65000) and potentially life-threatening disease due to the dysfunction of C1-inhibitor (C1-INH) protein, a key regulator of the complement, contact, and fibrinolytic systems. This evidence concerns the gene SERPING1 and hereditary angioedema.