Hereditary Angioedema

Hereditary angioedema is an immune disorder characterized by recurrent episodes of severe swelling. The most commonly affected areas of the body are the limbs, face, intestinal tract, and airway. HAE is caused by low levels or improper function of a protein called C1 inhibitor which affects the blood vessels. This condition is inherited in an autosomal dominant pattern.

There are three types of HAE, types I, II, and III. The types can be distinguished by their underlying causes and levels of C1 inhibitor in the blood. Type I and II are caused by mutations in the SERPING1 gene. Some cases of type III are associated with mutations in the F12 gene. Other genes are likely to be identified as the cause of other cases of HAE type III