Hereditary angioedema type 1 (HAE 1) 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 but HAE type 1 is the most common form of HAE accounting for 85% of the cases and is seen equally in males and females.
Like HAE 2 and 3 (see these terms), it occurs generally in childhood with symptoms becoming more severe in adolescence. Precipitating factors of HAE 1 thought to trigger attacks include: trauma, anxiety, puberty, infection, alcohol consumption, exercise and stress.
It is caused by a missence mutation in the SERPING1 gene encoding the C1 inhibitor (C1-INH). These mutations cause C1-INH levels to decrease 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