A More Universal Approach to Comprehensive Analysis of Thalassemia Alleles (CATSA)

The aim of the study was to assess the clinical utility of a third-generation sequencing (TGS) approach termed comprehensive analysis of thalassemia alleles (CATSA) for identifying both alpha and beta thalassemia genetic carrier status. Prospective blood samples (n = 1759) with abnormal hemoglobin parameters were screened for pathogenic thalassemia variants by CATSA on the PacBio TGS platform. In 1159 individuals, a total of 1317 pathogenic thalassemia variants were identified and confirmed by independent PCR-based tests. Of the total thalassemia variants detected, the alpha-variant_(SEA) (35.4%) and beta-variant c.126_129delCITT (15%) were the most common. CATSA was also able to detect three types of rare HBA structural variants as well as five rare HBA2, three HBA1, and 10 HBB single-nucleotide variations/insertions and deletions. Compared with standard thalassemia variant PCR panel testing, CATSA identified all panel variants present, with no falsenegative results. Carrier assignment was improved through identification of rare variants missed by the panel test. On the basis of allelic coverage, reliability, and accuracy, TGS with long-range PCR presents a comprehensive approach with the potential to provide a universal solution for thalassemia genetic carrier screening. It is proposed that CATSA has immediate clinical utility as an effective carrier screening approach for at-risk couples.

Automated summary

The study evaluated the clinical utility of a third-generation sequencing approach, CATSA, for diagnosing thalassemia genetic carriers. CATSA effectively identified pathogenic thalassemia variants, including rare ones, improving diagnostic accuracy for carriers.