C1 Esterase Inhibitor Deficiency
If you have a rare genetic condition known as hereditary angioedema (HAE), your healthcare provider may prescribe a medicine called C1 esterase inhibitor (Berinert®, Cinryze®). This drug contains a protein that is found naturally in the blood. It is prescribed to help relieve HAE attacks, which cause pain and swelling in various areas of the body.
HAE is caused by a deficiency of properly functioning C1 esterase inhibitor, which is a protein that helps regulate certain reactions in the body. Specifically, C1 inhibitor regulates the production of a chemical in the body called bradykinin that causes blood vessels to dilate (widen) and leak fluid into surrounding tissue. This leakage of fluid causes swelling and painful attacks associated with HAE.
People who have HAE do not produce enough C1 inhibitor, or produce C1 inhibitor that does not function properly. As a result, too much bradykinin is produced and the blood vessels leak fluid, causing painful swelling. C1 esterase inhibitor works by replacing C1 inhibitor that is missing or not working properly.
(Click What Is C1 Esterase Inhibitor Used For? for more detailed information on this topic.)