Hereditary Angioedema (HAE) is a rare genetic disorder that causes recurrent episodes of severe swelling in various parts of the body. This condition can significantly impact the quality of life and may become life-threatening without proper management.
What is Hereditary Angioedema (HAE)?
Hereditary Angioedema is an autosomal dominant disorder characterized by a deficiency or dysfunction of C1 esterase inhibitor (C1-INH). This protein is crucial for regulating inflammation and maintaining vascular permeability.
Types of Hereditary Angioedema
HAE is classified into three types:
- Type I HAE: Caused by low levels of functional C1-INH (accounts for 85% of cases).
- Type II HAE: Results from dysfunctional C1-INH despite normal protein levels (accounts for 15% of cases).
- Type III HAE: Often associated with mutations in the F12 gene and typically affects females.
Causes and Genetic Basis of Hereditary Angioedema
HAE is primarily caused by mutations in the SERPING1 gene, responsible for producing the C1-INH protein. These mutations lead to either insufficient production or defective function of this inhibitor, resulting in uncontrolled bradykinin production that causes severe swelling.
Symptoms of Hereditary Angioedema
The hallmark symptom of HAE is episodic swelling, which may affect:
- Extremities: Hands, feet, arms, and legs
- Gastrointestinal Tract: Abdominal pain, vomiting, and diarrhea
- Face and Throat: Swelling in the larynx may cause life-threatening airway obstruction
- Genitals: Uncomfortable and sometimes severe swelling
Trigger Factors for HAE Attacks
- Emotional stress
- Physical trauma
- Hormonal changes
- Medications such as ACE inhibitors
Diagnosis of Hereditary Angioedema
Proper diagnosis is essential for effective treatment. Diagnostic methods include:
- Blood Tests: To measure C1-INH levels and functionality
- Genetic Testing: Confirms mutations in the SERPING1 gene or related mutations
- Complement Studies: Evaluates complement C4 levels, typically low during attacks
Treatment and Management of Hereditary Angioedema
Effective management of HAE involves preventive strategies, acute treatment, and long-term therapies.
Acute Treatment for HAE Attacks
- C1-INH Concentrates: Rapidly control swelling by replacing the deficient protein
- Icatibant (Bradykinin B2 receptor antagonist): Blocks bradykinin activity
- Ecallantide: Inhibits kallikrein to reduce swelling progression
Long-term Preventive Treatment
- Lanadelumab: A monoclonal antibody that inhibits kallikrein activity
- C1-INH Prophylaxis: Routine infusions of C1-INH concentrate
- Androgens (e.g., Danazol): Stimulate C1-INH production but may cause side effects
Living with Hereditary Angioedema
Patients can effectively manage HAE with lifestyle adjustments and medical guidance:
- Identifying personal triggers
- Keeping emergency medications accessible
- Educating family and friends about the condition
Complications of Hereditary Angioedema
Untreated HAE can result in severe complications such as:
- Airway Obstruction: Potentially fatal without prompt treatment
- Intestinal Obstruction: Due to gastrointestinal swelling
- Emotional Distress: Chronic illness may lead to anxiety and depression
Frequently Asked Questions
What triggers hereditary angioedema attacks?
Common triggers include stress, injury, infection, and hormonal changes. Identifying personal triggers can help reduce episodes.
Is hereditary angioedema curable?
HAE cannot be cured but can be effectively managed with appropriate medications and preventive care.
Can children inherit hereditary angioedema?
Yes, HAE follows an autosomal dominant inheritance pattern, meaning a child has a 50% chance of inheriting the condition if one parent carries the mutated gene.
What should I do during an HAE attack?
Administer prescribed emergency medication immediately and seek medical attention if swelling affects the throat or airway.
Are there lifestyle changes that help manage HAE?
Yes, minimizing stress, avoiding known triggers, and following a proper treatment plan can improve symptom control and overall well-being.
