Hereditary alpha-tryptasemia testing in Western Australia: implementation and clinical impact

Hereditary α-tryptasemia (HαT) is an autosomal dominant trait defined by increased copy number of the α-tryptase gene ( TPSAB1 ), which leads to elevated basal serum tryptase and occurs in about 4–6% of the population. 1 HαT has emerged as the most frequent cause of unexplained elevated tryptase, accounting for up to about 72% of cases. 2 Although often asymptomatic, it can be associated with multisystem symptoms and a heightened risk of anaphylaxis. 1,2 Given the overlap with systemic mastocytosis, guidelines recommend screening for HαT via droplet digital PCR when investigating unexplained tryptase elevations. 3 Confirming HαT allows proper interpretation of tryptase levels and can avert unnecessary invasive investigations (e.g., bone marrow biopsy).