Hereditary Angioedema, or HAE, is a rare and potentially life threatening genetic condition that occurs in at least 6,500 people. Symptoms of HAE include episodes of inflammation in almost any body part including the hands, feet, face, and airway. This inflammation can be disfiguring, debilitating and in the case of laryngeal (airway/windpipe) attacks, life-threatening.
The cause of HAE is directly linked to C1 esterase inhibitor (C1-INH), a naturally occurring protease inhibitor that mediates inflammation. Most people make normal levels of C1 INH, throughout their lives, and therefore will never experience HAE. However, when a patient depletes his or her C1-INH, either because of decreased production or production of functionally impaired inhibitor, the patient may suffer the dangerous manifestations of the disease.
HAE may be passed on to children of people with HAE. Because it is an autosomal dominant disease, patients with HAE generally inherit one normal gene and one abnormal gene. Thus, children of HAE patients have a 50% chance of inheriting the disease from their parents. In addition, 20% to 25% of all HAE cases are as a result of spontaneous mutations in persons with no family history of the disease.
Learn more about Function of C1 Esterase Inhibitor in the Normal Contact Pathway and The Contact System in Patients with Hereditary Angioedema
Symptoms of an attack generally show as an inflammation, or swelling, in one or more body systems. The most common sites of an attack include the skin or arms/legs, which can be functionally disabling, gastrointestinal system, or respiratory tracts. More severe forms of HAE include windpipe and upper airway inflammation. Such attacks are very dangerous; patients often must undergo tracheotomy (surgery to insert a breathing tube into the windpipe) and intubation (the placement of a breathing tube into the windpipe via the mouth), and death may occur in as little as 20 minutes, and in such attacks, 40% of patients die if left untreated. Unfortunately, patients with no previous history of laryngeal attacks are still at risk for asphyxiation as there is no correlation between historical and future attacks.
HAE is underdiagnosed, and estimated to occur in at least 6,000 people in the United States. Patients suffering from symptomatic HAE generally have at least one attack per month, though many have far more. Most attacks last 2 to 5 days, resulting in between 20 and 100 days of incapacitation per year. Attacks occur without warning, or may be triggered by trauma, surgery, dental procedures, emotional stress, infections, and other causes. Due to this inactivity, HAE patients frequently find their ability to accomplish daily activities significantly reduced. HAE attacks have historically accounted for 15,000 to 30,000 emergency room visits each year in the U.S. And, because symptoms of HAE in the intestines can mimic a surgical emergency, about one-third of patients with undiagnosed HAE have been reported to have undergone unnecessary surgery during abdominal attacks.
Please see your doctor for more information on hereditary angioedema and available preventative therapies.
For more information online, please visit the U.S. HAE Association’s website at: www.haea.org.