Approximately 300 Americans suffer painful random swelling in their arms, legs, face, lungs, and other parts of the body due to a rare disease called hereditary angioedema. This condition can be life-threatening—swelling in the airway can made breathing impossible—but it can be difficult to diagnose. That’s because the symptoms mimic those of other, more common illnesses, and doctors often don’t even consider hereditary angioedema as a possibility. In addition to the airway, other internal organs can be affected, such as the intestines. In addition to damaging the intestines directly, this can lead to malnutrition.
The condition, as the name suggests, is usually inherited. In particular, mutations in genes responsible for proteins called C1 inhibitors cause the proteins to be missing or abnormal. This points to an autoimmune aspect to hereditary angioedema. When C1 inhibitor doesn’t properly perform its function, substances called peptides build up and lead to swelling. The symptoms of the condition can vary significantly from patient to patient, or even over the course of a lifetime for a single patient. In addition, because it is such a rare condition, doctors often don’t consider it as a possibility even when the symptoms all seem consistent with that diagnosis. Often sufferers are told their discomfort is psychosomatic, with no physical cause.
In 2010, a drug called icatibant was found to be effective in treating hereditary angioedema. The discovery was made by a team at Massachusetts General Hospital led by Aleena Banerji. Icatibant works by blocking the bradykinin receptor, a site in the body involved in pain and inflammation, so that the built-up peptides have no place to go and don’t lead to swelling.
“We have not had many options for treating painful, debilitating and potentially life-threatening attacks of hereditary angioedema, and these studies showed that icatibant improves symptoms and is not associated with any concerning side effects, Dr. Banerji said in a statement. Other treatments include replacing the insufficient C1 inhibitor directly and administering drugs to jump-start the production of the protein.