Hereditary alpha tryptasemia is not associated with specific clinical phenotypes

Area of Science:

• Genetics
• Clinical Medicine
• Immunology

Background:

• Hereditary alpha tryptasemia (HαT) affects ~7% of the population, with variable associations to symptoms like reflux, joint hypermobility, and allergies.
• Current understanding is limited by few studies, referral bias, and conflicting clinical presentations.

Purpose of the Study:

• To evaluate the clinical phenotype of HαT in a general population biorepository.
• To compare HαT phenotype in allergy clinic patients with and without mastocytosis.

Main Methods:

• Assessed tryptase copy number allele using digital droplet PCR.
• Conducted clinician interviews, examinations, and symptom surveys for participants with and without HαT.

Main Results:

• HαT identified in 7.5% of biorepository samples and 18% of mastocytosis patients.
• No significant differences in clinical symptoms or medical history between HαT individuals and controls.
• Higher average baseline serum tryptase in HαT individuals, but no difference in urinary mast cell activation markers.

Conclusions:

• Elevated baseline serum tryptase is the sole consistent phenotypic marker for HαT.
• HαT is more frequent in mastocytosis patients than in the general population.