Hereditary alpha tryptasemia syndrome

Hereditary Alpha Tryptasemia Syndrome or hereditary α-tryptasemia syndrome or HATS is a genetic and multi-systemic disease caused by an increased copy number α-tryptase-encoding regions on the TPSAB1 (TPSAB1) gene.

Hereditary alpha tryptasemia/familial hypertryptasemia

Hereditary alpha tryptasemia (H⍺T or HAT), alternatively known as familial hypertryptasemia (FHT), is common in the general population, affecting around 1 in 20 people, and is often asymptomatic.

Hereditary alpha tryptasemia syndrome (HATS) is only diagnosed when a cluster of associated symptoms are also present.

Signs and symptoms

Hereditary Alpha Tryptasemia Syndrome symptoms include:

• a high baseline tryp­tase level (over 8 μg/L or over 11μg/L, depending on the criteria used)
• positive tilt table test/dysautonomia e.g. postural orthostatic tachycardia syndrome (POTS)
• chronic gastroesophageal reflux disease (GERD)
• flushing/pruritus
• Gastrointestinal dysmotility, bloating, abdominal pain, diarrhea and/or constipation, which may be diagnosed as irritable bowel syndrome (IBS) and may meet the Rome III criteria
• chronic pain or joint pains
• Ehlers-Danlos syndrome or hereditary skeletal abnormality
• other connective tissue problems e.g. joint hypermobility or scoliosis
• urticaria (hives) or skin itching
• cardiac symptoms such as a racing or pounding heart, blood pressure swings sometimes with fainting
• anxiety, panic attacks, or depression
• retained primary dentition (retained baby teeth)
• systemic venom reaction, e.g. serious bee sting allergy
  

The TPSAB1 has also been implicated in unexplained gastrointestinal symptoms and mast cell activation.

See also

• Mast cell activation syndrome
• Tryptase alpha/beta 1 (TPSAB1)
• Ehlers-Danlos syndrome

Learn more

• Hereditary Alpha Tryptasemia and Hereditary Alpha Tryptasemia Syndrome: FAQ - National Institute of Allergy and Infectious Diseases

α α / Α. Greek letter alpha or alfa (a symbol used in science), equivalent to "a".

μg A microgram, a millionth of a gram. Micrograms can be written as mcg or μg. 1000 micrograms (1000mcg) is equivalent to 1 milligram (1mg).

μg A microgram, a millionth of a gram. Micrograms can be written as mcg or μg. 1000 micrograms (1000mcg) is equivalent to 1 milligram (1mg).

postural orthostatic tachycardia syndrome (POTS) - A form of orthostatic intolerance where the cardinal symptom is excessive tachycardia due to changing position (e.g. from lying down to sitting up).

mastocytosis A type of mast cell disease in which chronic symptoms are related to overproduction or over-accumulation of mast cells. Not to be confused with Mast Cell Activation Syndrome (MCAS), where there are normal numbers of mast cells, but abnormal activity.