BioHAE – Biomarker for Hereditary Angioedema Disease Type 1
Hereditary angioedema is a rare inherited disorder characterized by recurrent episodes of the accumulation of fluids outside of the blood vessels, blocking the normal flow of blood or lymphatic fluid and causing rapid swelling of tissues in the hands, feet, limbs, face, intestinal tract, or airway. Usually, this swelling is not accompanied by itching, as it might be with an allergic reaction. Swelling of the gastrointestinal tract leads to cramping. Swelling of the airway may lead to obstruction, a potentially very serious complication. These symptoms develop as the result of deficiency or improper functioning of certain proteins that help to maintain the normal flow of fluids through very small blood vessels (capillaries).
In some cases, fluid may accumulate in other internal organs. The severity of the disease varies greatly among affected individuals. The most common form of the disorder is hereditary angioedema type I, which is the result of abnormally low levels of certain complex proteins in the blood (C1 esterase inhibitors), known as complements. They help to regulate various body functions.
The characteristic symptom of hereditary angioedema is recurrent episodes of swelling of affected areas due to the accumulation of excessive body fluid. The areas of the body most commonly affected include the hands, feet, eyelids, lips, and/or genitals. Edema may also occur in the mucous membranes that line the respiratory and digestive tracts, which is more common in people with hereditary angioedema than in those who have other forms of angioedema (i.e., acquired or traumatic). People with this disorder typically have areas of swelling that are hard and painful, not red and itchy (pruritic). A skin rash (urticaria) rarely is present.
The symptoms of hereditary angioedema may recur and can become more severe. Injury, severe pain, surgery, dental procedures, viral illness, and/or stress can trigger or worsen the recurring symptoms.
Symptoms associated with swelling in the digestive system (gastrointestinal tract) include nausea, vomiting, acute abdominal pain, and/or other signs of obstruction. Edema of the throat (pharynx) or voice-box (larynx) can result in pain, difficulty swallowing (dysphagia), difficulty speaking (dysphonia), noisy respiration (stridor), and potentially life-threatening asphyxiation.
Hereditary angioedema is inherited as an autosomal dominant trait. Genetic diseases are determined by two genes, one received from the father and one from the mother.
Dominant genetic disorders occur when only a single copy of an abnormal gene is necessary for the appearance of the disease. The abnormal gene can be inherited from either parent, or can be the result of a spontaneous new mutation (gene change) in the affected individual.
The symptoms of hereditary angioedema type I develop due to a deficiency of a protein known as complement component C1 esterase inhibitor.