1. Screening and Diagnosis of Rare Thalassemia Variants Is Third-Generation Sequencing Enough?
- Author
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Tang, Haishen, Xiong, Yi, Tang, Jiaqi, Wang, Xiaohong, Wang, Ya, Huang, Liping, Wang, Runli, and Wang, Degang
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Diagnosis ,Physiological aspects ,Usage ,Methods ,Health screening -- Methods ,DNA sequencing -- Usage ,Medical research ,Thalassemia -- Diagnosis -- Physiological aspects ,Nucleotide sequencing -- Usage ,Medicine, Experimental ,Medical screening -- Methods - Abstract
Thalassemia is a group of hereditary anemias caused by mutations to the globin gene, which cause significant morbidity and mortality worldwide, especially among populations in Southeast Asia, the Middle East, [...], * Context.--Rare thalassemia subtypes are often undiagnosed because conventional testing methods can only identify 23 common types of [alpha]- and [beta]-thalassemia. Objective.--To assess a comprehensive approach for the screening and diagnosis of rare thalassemia. Design.--The study cohort included 72 individuals with suspected rare thalassemia variants. Screening was conducted by next-generation sequencing (NGS) combined with third-generation sequencing (TGS) and chromosomal microarray analysis (CMA)/copy number variation sequencing. Results.--Of the 72 individuals with suspected rare thalassemia, 49 had rare [alpha]- [beta]-gene variants. NGS combined with gap polymerase chain reaction detected a total of 42 cases, resulting in a positive detection rate of 58.3%. Additionally, 4 [alpha]-globin genetic deletions were identified by TGS, which increased the variant detection rate by 5.6%. Two samples with a microdeletion of chromosome 16 or 11 were detected by CMA, which increased the detection rate by 2.8%. For one sample, reanalysis of the NGS and TGS data confirmed the presence of the [[beta].sup.41-42]/[[beta].sup.N] and [[beta].sup.N]/[[beta].sup.N] mosaic. The HBB:c.315 1 2delT mutation was initially reported in Guangdong Province, China. Two HBB gene mutations (HBB:c.315 1 5G>C and HBB:c.295G>A) and 4 rare HBA gene deletions ([-.sup.11.1], -[[alpha].sup.27.6], -[[alpha].sup.2.4], and -[[alpha].sup.21.9]) were initially identified in the Zhonshan region. The hematologic phenotypes of all rare cases in this study were clarified. Conclusions.--Rare thalassemia variants are more common than previously thought. Despite advancements in TGS, there is still no foolproof method for detection of all types of thalassemia. Thus, a comprehensive approach is necessary for accurate screening and diagnosis of rare thalassemia variants. (Arch Pathol Lab Med. 2025;149:e1-e10; doi: 10.5858/arpa.2023-0382-OA)
- Published
- 2025
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