Hereditary angioedema

Hereditary angioedema (HAE) is a rare genetic disorder, manifested by recurrent episodes of angioedema localized to the skin or mucosa of the gastrointestinal tract or larynx. The laryngeal angioedema is potentially lethal. The classic forms, HAE types I and II, result from deficiency of the plasma protease inhibitor, C1 inhibitor (C1INH). Type I HAE is caused by decreased expression of C1INH in the plasma whereas type 2 HAE, consisting approximately 15% of patients with HAE, is due to expression of a dysfunctional C1INH protein. HAE type III has been observed exclusively in women and appears to be correlated with high estrogen levels.