Application of third-generation sequencing technology for identifying rare α- and β-globin gene variants in a Southeast Chinese region.

Background: Third-generation sequencing (TGS) based on long-read technology has been gradually used in identifying thalassemia and hemoglobin (Hb) variants. The aim of the present study was to explore genotype varieties of thalassemia and Hb variants in Quanzhou region of Southeast China by TGS.

Methods: Included in this study were 6,174 subjects with thalassemia traits from Quanzhou region of Southeast China. All of them underwent common thalassemia gene testing using the DNA reverse dot-blot hybridization technology. Subjects who were suspected as rare thalassemia carriers were further subjected to TGS to identify rare or novel α- and β-globin gene variants, and the results were verified by Sanger sequencing and/or gap PCR.

Results: Of the 6,174 included subjects, 2,390 (38.71%) were identified as α- and β-globin gene mutation carriers, including 40 carrying rare or novel α- and β-thalassemia mutations. The α^CD30(-GAG)α and Hb Lepore-Boston-Washington were first reported in Fujian province Southeast China. Moreover, the β^{CD15(TGG> TAG)}, β^IVS-II-761, β⁰-Filipino(~ 45 kb deletion), and Hb Lepore-Quanzhou were first identified in the Chinese population. In addition, 35 cases of Hb variants were detected, the rare Hb variants of Hb Jilin and Hb Beijing were first reported in Fujian province of China. Among them, one case with compound ααα^anti3.7 and Hb G-Honolulu variants was identified in this study.

Conclusion: Our findings may provide valuable data for enriching the spectrum of thalassemia and highlight the clinical application value of TGS-based α- and β-globin genetic testing.