What is Hereditary Angioedema?
Hereditary angioedema (HAE) is a rare genetic disorder that affects approximately 1 in 50,000 people. It is caused by a deficiency or dysfunction of C1 inhibitor, a protein that helps to regulate inflammation and the immune system. Without enough functional C1 inhibitor, the body produces excess bradykinin, a peptide that causes blood vessels to become leaky and results in swelling in various parts of the body.
HAE can be divided into three types: type I, type II, and type III. Type I HAE is the most common form and is characterized by low levels of C1 inhibitor protein in the blood. Type II HAE is characterized by normal or elevated levels of C1 inhibitor protein but with dysfunctional protein activity. Type III HAE is a rare form that predominantly affects women and is associated with mutations in the F12 gene, which encodes for factor XII, a protein involved in the coagulation system.
Symptoms of HAE usually start in childhood or adolescence, but they can develop at any age. The most common symptom is recurrent episodes of swelling, which can occur in the skin, mucous membranes, and internal organs. Swelling in the skin usually presents as a red, raised, and itchy patch that can be painful to the touch. Swelling in the mucous membranes can occur in the face, mouth, throat, or gastrointestinal tract and can result in difficulty breathing, speaking, or swallowing. Swelling in the internal organs, such as the kidneys or liver, can cause abdominal pain and vomiting.
HAE attacks are often unpredictable, and their severity and duration can vary. Some attacks are mild and resolve on their own within a few days, while others can be life-threatening if they affect the airways or gastrointestinal tract. Patients with HAE can also experience non-swelling symptoms, such as fatigue, muscle pain, and joint pain.
Diagnosis of HAE is usually made based on the patient’s clinical history, family history, and laboratory tests. Laboratory tests can include measuring C1 inhibitor levels and activity, as well as testing for genetic mutations associated with HAE.
Treatment of HAE is aimed at preventing or managing attacks. There are several medications available for HAE, including plasma-derived or recombinant C1 inhibitor protein, bradykinin receptor antagonists, and kallikrein inhibitors. These medications can be given prophylactically to prevent attacks or acutely to treat ongoing attacks. Some patients may also benefit from regular infusion of these medications to prevent attacks.
In addition to medication, patients with HAE can also take steps to manage their condition and prevent attacks. These steps may include avoiding triggers, such as certain medications or physical trauma, and having an action plan in place in case of an attack. Patients with HAE may also benefit from joining a support group or working with a healthcare professional who is knowledgeable about the disorder.
In conclusion, hereditary angioedema is a rare genetic disorder that can result in recurrent episodes of swelling in various parts of the body. It is caused by a deficiency or dysfunction of C1 inhibitor, a protein that helps to regulate inflammation and the immune system. Diagnosis of HAE is usually made based on the patient’s clinical history, family history, and laboratory tests. Treatment of HAE is aimed at preventing or managing attacks, and there are several medications available for HAE. Patients with HAE can also take steps to manage their condition and prevent attacks, such as avoiding triggers and having an action plan in place.