Hereditary Angioedema

Hereditary angioedema is a rare hereditary disease that causes episodic swelling and frequently pain in specific areas of the body such as the abdomen, hands, feet, arms, legs, genitals, neck and face. Depending on the severity of the disease, some people have several episodes a month, others remain symptom-free and pain-free for months on end. The inherited genetic defect affects the production of an enzyme, C1-esterase inhibitor (C1-INH). People with this disease produce either too little or non-functional C1-esterase inhibitor. Hereditary angioedema is divided into three types, depending on the underlying genetic defect. A person may have low C1-INH levels (type 1), poorly functioning C1-INH (type 2) or hereditary angioedema with normally functioning C1-INH (formerly known as type 3). This last type is extremely rare and the clinical picture of the disease has not been fully explained.