Hereditary angioedema (HAE) is a rare disease that can typically cause attacks of swelling in the stomach (abdomen), face, feet, genitals, hands, and throat
It is estimated that HAE affects between 1 in 10,000 and 1 in 50,000 people worldwide.
Most people with HAE either do not have enough of a protein called C1 esterase inhibitor (C1-INH) or this protein does not work as it should, which contributes to a cascade of events in the body.
This cascade causes another protein called plasma kallikrein to trigger the release of a third protein called bradykinin. Having too much bradykinin causes the blood vessels to release fluid, resulting in localized swelling.
Types of HAE
There are two main types of HAE, called type 1 and type 2.
- Type 1 is the most common form. People with type 1 do not make enough of the protein C1-INH, so circulating levels in the blood are too low.
- People with HAE type 2 have normal, or even higher, levels of C1-INH, but this protein does not work as it should.