Hereditary alpha tryptasemia is not associated with specific clinical phenotypes

Background: Hereditary alpha tryptasemia (H alpha T) is found in approximately 7% of the population. Associations with a variety of clinical symptoms including gastric reflux, joint hypermobility, dysautonomia, flushing and pruritus, and hymenoptera allergy have variably been described in prior reports. However, our understanding of this genetic trait is limited by a paucity of published studies, referral bias, and conflicting findings at clinical presentation. Objective: The purpose of this study was to assess the clinical phenotype of H alpha T in a random biorepository population and in patients with and without mastocytosis referred to the allergy clinic. Methods: Tryptase copy number allele was assessed using digital droplet PCR. Participants with or without H alpha T were interviewed and examined by a clinician and surveyed regarding their medical history and symptomology. Results: H alpha T was identified in 7.5% of the random biorepository samples and in 18% of patients with mastocytosis. There was no difference in the clinical symptomology or medical history of individuals with H alpha T compared to controls. Average baseline serum tryptase was higher in individuals with H alpha T compared to controls, but there was no difference in urinary mast cell activation products. Conclusions: Elevated baseline serum tryptase was the only consistent phenotypic marker for H alpha T in this study. There was a higher frequency of H alpha T in patients with mastocytosis than in the general population.

Automated summary

This study found that the prevalence of H alpha T in a random biorepository population was 7.5% and in patients with mastocytosis was 18%. There were no differences in clinical symptomology or medical history between individuals with H alpha T and controls. Elevated baseline serum tryptase was the only consistent phenotypic marker for H alpha T in this study.