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Objectives: Accurate epidemiological data are crucial for effective disease prevention and treatment. We conducted a large-scale survey to explore the thalassaemia prevalence and spectrum among the two major ethnic groups in Hainan Province. Methods: A total of 399,053 childbearing-age individuals of Li (n = 77,563) and Han(n = 321,490) ethnic groups were recruited from 18 cities and counties in Hainan, and their thalassemia genotypes were systematically screened and statistically analysed. Results: This study revealed a significantly higher thalassaemia carrier rate in the Li (55.39%) than that in the Han (13.13%). Specifically, the carrier rate of α-thalassaemia was 46.39% in the Li and 10.02% in the Han. The predominant α-thalassaemia mutations were – α3.7 and – α42. in Li, whereas the main mutation were – SEA and – α4.2 in Han. For β-thalassaemia, the carrier rates were 1.68% in Li and 2.38% in Han, with CD41-42(-CTTT) the most prevalent mutation in both groups. The carrier rates of β-/α-compound thalassaemia were 7.32% in Li and 0.73% in Han. Additionally, there were regional differences in the distribution of thalassemia among the Li and Han within Hainan Province. Conclusion: Epidemiological characteristics and molecular spectrum of thalassaemia among the Li and Han ethnic groups in Hainan were revealed in this study. These findings can provide a scientific basis to develop and implement prevention strategies for thalassaemia in Hainan. [ABSTRACT FROM AUTHOR]

Background: Oxford Nanopore Technology (ONT) third-generation sequencing (TGS) is a versatile genetic diagnostic platform. However, it is nonetheless challenging to prepare long-template libraries for long-read TGS, particularly the ONT method for analysis of hemoglobinopathy variants involving complex structures and occurring in GC-rich and/or homologous regions., Methods: A multiplex long PCR was designed to prepare library templates, including the whole-gene amplicons for HBA2/1, HBG2/1, HBD, and HBB, as well as the allelic amplicons for targeted deletions and special structural variations. Library construction was performed using long-PCR products, and sequencing was conducted on an Oxford Nanopore MinION instrument. Genotypes were identified based on integrative genomics viewer (IGV) plots., Results: This novel long-read TGS method distinguished all single nucleotide variants and structural variants within HBA2/1, HBG2/1, HBD, and HBB based on the whole-gene sequence reads. Targeted deletions and special structural variations were also identified according to the specific allelic reads. The result of 158 α-/β-thalassemia samples showed 100% concordance with previously known genotypes., Conclusions: This ONT TGS method is high-throughput, which can be used for molecular screening and genetic diagnosis of hemoglobinopathies. The strategy of multiplex long PCR is an efficient strategy for library preparation, providing a practical reference for TGS assay development., (© American Association for Clinical Chemistry 2023. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)