What is Hereditary Angioedema
Have you ever heard of hereditary angioedema (HAE)? For most non-medical professionals, the answer is probably “no”. This is because HAE is very rare, with approximately 1 in 50,000 people being affected globally. The lack of awareness poses significant challenges to affected individuals, as well as those around them. It can lead to delayed diagnoses, misdiagnoses, and a lack of funding and resources that could be used toward researching better treatment methods and management strategies.
Reading this article will teach you what hereditary angioedema is, help you understand its genetic cause and risk factors, and touch on how this condition is diagnosed and treated.
What is Hereditary Angioedema?
As the name suggests, hereditary angioedema is a genetic disorder that is hereditary and runs in families. Affected people usually begin to show symptoms in childhood or adolescence, which then worsen during puberty. Since the disorder is rare and presents with severe and painful recurring swelling in different parts of the body, misdiagnosis with allergies or stress-related conditions is common. More specifically, symptoms include swelling in the hands, feet, face, abdomen, throat, and genitals. Swelling in the abdomen is easily confused with stomach problems, since it presents with cramps, nausea, vomiting, and diarrhea. While these symptoms can be highly uncomfortable, airway swelling is the most dangerous and can be life-threatening. It’s important to stress that hereditary angioedema is different fromallergic angioedema, since standard allergy medications like antihistamines are ineffective in HAE.
The Genetic Cause and Risk Factors
A mutation in theSERPING1 gene is most commonly the root cause of hereditary angioedema, or less often, the F12 gene. Both affect the C1 inhibitor protein (C1-INH), leading to the uncontrolled release of a molecule called bradykinin, which triggers swelling. If one parent carries a mutated SERPING1 or F12 gene, a child has a 50% chance of inheriting HAE. While males and females are equally likely to inherit the condition, women may experience more frequent and severe attacks due to hormonal influence. Also, in approximately 25% of all HAE cases, spontaneous gene mutations occur without a family history. Apart from the underlying genetic cause for HAE, there are multiple factors which may trigger an attack. These include injury, illness, surgery, as well as emotional stress or anxiety. Hormonal influences like puberty, pregnancy, and menstruation, as well as certain medications, including ACE inhibitors and some blood pressure drugs, can worsen or trigger swelling.
Managing Hereditary Angioedema
Now that you know what hereditary angioedema is, you may wonder about diagnosis and treatment options. HAE is diagnosed based on a combination of clinical and family history, blood tests, and genetic testing. Once hereditary angioedema has been detected, a doctor will typically prescribe long-term treatment aimed at preventing or reducing the frequency of attacks. These include regular C1-INH infusions, lanadelumab, and berotralstat.
However, despite long-term therapy, attacks can't usually be averted entirely. When they do occur, they are considered a medical emergency and require immediate treatment using on-demand therapies that target the molecule bradykinin or replace C1-INH, like C1-INH concentrate, icatibant, and ecallantide. These medications should be available to patients at all times. In most severe cases, intubation may be necessary.
Alongside medications, several other strategies can help you manage this condition. This can include avoiding known triggers, having an emergency plan in place, and educating those around you to ensure they can recognize the signs of an emergency and know how to help you. With today’s therapies, people with HAE can live everyday lives, but further awareness and research can help improve outcomes.
