Hereditary angioedema type 2 (HAE 2) is a form of hereditary angioedema (see this term) characterized by acute edema in subcutaneous tissues, viscera and/or the upper airway.
Prevalence is unknown. HAE 2 is the less common form of HAE, accounting for 15% of HAE cases and is seen equally in men and women.
Like HAE 1 and 3 (see these terms) it occurs generally in childhood with symptoms becoming more severe in adolescence. Precipitating factors of HAE 2 thought to trigger attacks include: trauma, anxiety, puberty, infection, alcohol consumption, exercise and stress.
It is caused by deletions, frameshift or splice mutations in the SERPING1 gene encoding the C1 inhibitor (C1-INH). These mutations cause a decrease in C1-INH activity (while C1 inhibitor serum levels remain normal) leading to an increase in bradykinin formation.
Treatment usually consists of intravenous C1 inhibitor concentrate or subcutaneous administration of the orphan drug icatibant (bradykinin receptor antagonist). Prophylaxis with danazol is often given before surgical procedures.
Last update: August 2011