Hereditary Angioedema

Hereditary angioedema (HAE) is a disease characterized by recurrent episodes (also called attacks) of severe swelling of the skin and mucous membranes. The frequency of attacks usually increases after puberty. Attacks most often affect 3 parts of the body: Skin - the most common sites are the face (such as the lips and eyes), hands, arms, legs, genitals, and buttocks. Skin swelling can cause pain, dysfunction, and disfigurement, although it is generally not dangerous and is temporary. Gastrointestinal tract - the stomach, intestines, bladder, and/or urethra may be involved. This may cause symptoms such as nausea, vomiting, diarrhea, and abdominal pain. Upper airway (such as the larynx and tongue) - this can cause upper airway obstruction. The majority of attacks affecting the airway resolve before complete airway obstruction. Attacks may involve one area of the body at a time, or they may involve a combination of areas. They always go away on their own but last from 2 to 4 days. While people with HAE have reported various triggers of attacks, emotional stress, physical stress, and dental procedures are the most commonly reported triggers. HAE may be caused by genetic changes (pathogenic variants) in the C1NH gene (also called the SERPING1 gene) or in the F12 gene. In some cases, the cause is not yet known. These types are also characterized by abnormal complement protein levels. Inheritance is autosomal dominant, but not all people with a SERPING1 genetic change will develop symptoms of HAE. Attacks generally continue throughout life, but the frequency of attacks can be significantly reduced with therapy.

Genetic Mutations: Hereditary angioedema is caused by genetic mutations, also known as pathogenic variants. Genetic mutations can be hereditary, when parents pass them down to their children, or they may occur randomly when cells are dividing. Genetic mutations may also result from contracted viruses, environmental factors, such as UV radiation from sunlight exposure, or a combination of any of these.

If you suspect you may have this disease, you may want to start collecting your family health history. Information such as other family members who have had similar symptoms, when their/your symptoms first appeared, or exposures to any potential disease-causing environmental factors should be discussed with your medical team.

Yes. It is possible for a biological parent to pass down genetic mutations that cause or increase the chances of getting this disease to their child. This is known as inheritance. Knowing whether other family members have previously had this disease, also known as family health history, can be very important information for your medical team.

There are multiple ways, or patterns, a disease can be inherited depending on the gene(s) involved. Based on GARD’s current data, this disease can be inherited in the following pattern(s):

Autosomal Dominant: Autosomal means the gene involved is located on one of the numbered chromosomes. Dominant means that a child only needs to inherit one copy of the mutated gene, from either biological parent, to be affected by the disease.

People affected by an autosomal dominant disease have a 50% chance of passing on the mutated gene to their biological child.