Hereditary Angioedema (HAE) is a rare genetic disorder most often caused by a lack of a functional or sufficient amount of a protein called C1 esterase inhibitor (C1-INH). This protein is needed to help regulate several complex processes involved in immune system function, blood clotting, and bleeding. Without the correct level of C1-INH, a peptide called bradykinin may be overproduced which may cause fluids to build up in body tissues (edema).

It is estimated that hereditary angioedema occurs in 1 in 10,000 to 1 in 50,000 people. Because HAE is rare and under-recognized, HAE symptoms are frequently misdiagnosed as other, more common conditions.

Symptoms of hereditary angioedema include unpredictable recurrent attacks of swelling commonly affecting the hands, feet, arms, legs, face, abdomen, tongue, genitals and larynx (throat). Attacks involving the abdomen are often associated with severe pain, vomiting and diarrhea. Attacks of the larynx can lead to airway obstruction and can be life threatening.  During an attack, swelling might occur in only one or multiple locations.  HAE symptoms usually start in childhood, can become worse at puberty, and continue throughout life.  The frequency, severity and location of attacks are often quite variable.  

Resources And Organizations

The following organizations may be a resource for information and support for patients, families, and caregivers. Always speak with a physician or healthcare provider regarding any questions you may have about HAE.