Hereditary alpha tryptasemia
What is Tryptase
Tryptase is a protein that can circulate in your bloodstream. It is made primarily by cells that are present around blood vessels and in the bone marrow called mast cells, and it is used largely as a marker for mast cell activation, as it can be easily measured by a blood test, especially after certain allergic reactions.
What is a mast cell
A mast cell is a cell that is made in the bone marrow and is associated with allergic reactions; it matures in places like the skin, lungs, and gastrointestinal tract. Mast cells may play a role in protecting us from parasites but also can contribute to allergic responses by releasing molecules such as histamine in response to allergens.
Hereditary Alpha Tryptasemia "HAT"
Hereditary alpha tryptasemia can be called a biochemical trait. A trait is simply a characteristic that is caused by a difference in the DNA. In the case of hereditary alpha tryptasemia, people with this trait have inherited extra copies of the alpha tryptase gene (TPSAB1), leading to increased levels of tryptase protein detected in the blood, whether a reaction is happening or not.
How common is HAT
Elevated serum tryptase is present in perhaps up to 6 percent of the general population. While large studies of multiple different ethnicities need to be done, the estimate is that hereditary alpha tryptasemia may be present in a similar percentage of the general population.
How common is HAT continuation
This means that millions of people could carry multiple copies of the alpha tryptase gene, so it should be no surprise that some people will have more than one explanation for their symptoms. Again, it must be stressed that there is great variability from person to person regarding what symptoms the duplications or triplications do or do not cause.
What is HAT Syndrome
In addition to having higher blood tryptase levels, individuals with more alpha tryptase copies also report more shared symptoms. These symptoms can be associated with multiple organ systems and may be hard to explain.
What is HAT Syndrome Continuation
These symptoms may include allergic-like symptoms such as skin itching, flushing, hives, and even anaphylaxis; gastrointestinal (GI) symptoms such as bloating, abdominal pain, diarrhea, and/or constipation (frequently diagnosed as irritable bowel syndrome or IBS), heartburn, reflux, and difficulty swallowing; connective tissue symptoms such as hyper-mobile joints and scoliosis; cardiac symptoms such as a racing or pounding heartbeat or blood pressure swings sometimes with fainting; as well as anxiety, depression, chronic pain, panic attacks, and others.
What is HAT Syndrome cont..
Patients may find that others in their family have similar or related symptoms, as this is a genetic syndrome. Others may have few, if any, symptoms—and would be said only to have the trait and not the syndrome associated with the trait. In such cases, a person may only find out because a relative was more severely affected by the syndrome.
How do I know if I have HAT?
If you have a blood tryptase level above 10 ng/mL, in particular if another close relative also has a similarly elevated level, you are more likely to have hereditary alpha tryptasemia. However, a wide range of symptoms has been reported among individuals with the associated syndrome, many of which can be rather common, so it is difficult to know who has it from symptoms alone.
How do I know if I have HAT cont...
- Chronic skin flushing, itching, or hives
- Bee sting allergy
- Dizziness and/or difficulty maintaining a normal pulse and blood pressure
- Chronic head, back, and joint pain
- Skeletal abnormalities
- GI disturbances, including IBS, and numerous food and drug reactions and intolerances
- Sleep disturbances
