The Study Of The Genotypes And Phenotypes Interactions Of β-thalassemia/Hemoglobin E In Guangxi Province

Objective To study the cases of beta?thalassemia/ hemoglobin E (β?thal /Hb E) in Guangxi Province of China, to find out its incidence and distribution, and to discover the relationships between the genotypes and phenotypes. Methods To detect genotypes of α- and β- thalassemia(α- and β- thal), Gγ?158 C→T mutation by polymerase chain reaction(PCR), reverse dot-blot hybridization(RDB), Xmn I restriction enzyme analysis and DNA sequencing. Results There were six kinds genotypes of β-thal among 29 cases with β/ Hb E . They were CD41-42/ Hb E, CD17/ Hb E, CD71-72/ Hb E, CD43/ Hb E, CD17/ Hb E and IVS-Ι-1/ Hb E. Among them, 13 cases were CD41-42/ Hb E genotypes, accounted for 45%; while 9 cases with CD17/ Hb E, accounted for 31.0%; 3 cases with CD71-72/ Hb E, accounted for 10.3%; 2 cases with TATAnt-28, accounted 6.8%; 1 cases with CD43/ Hb E, accounted 3.45% and 1 cases with IVS-I-1/ Hb E, accounted 3.45%. Two kinds genotypes of α-thal, southeast Asia Type of deletional α-thal-1(SEA) and deletional -α4.2-thal-2 were detected. But deletional -α3.7-thal-2 and Hb constant Spring were not detected. Among 29 cases with β/Hb E, 2 cases co-inhereitanted with SEA-α-thal-1, while 3 cases with deletional -α4.2-thal-2. About Gγ?158 C→T mutation, 11 heterozygotes were detectable, accounted for 37.9%, while 1 homozygote was detedted, accounted for 3.45%. 17 cases had no Gγ?158 C→T mutations, accounted for 58.6%. For the clinical phenotypes of these patients with β/Hb E, most of them were nitermediate, some of them were mild or severe. Conclusion 1. We have identified the genotypes of β-thal/ Hb E in Guangxi Province. They were CD41/42, CD17, CD71/72, TATAnt-28, IVS-I-1 and CD43 mutations, and CD41/42 and CD17 mutations were more commom. When β?thalassemia combined with Hb E, most of their phenotypes were intermediate, some were mild or severe. 2. When β/Hb E combined with α-thalassemia, their clinical severity could be improved, according to their genotypes of α-thalassemia. The clinical severeity of those cases with SEA-α-thal-1 were mild than that of those with -α4.2-thal-2. 3. The phenotypes of cases with Gγ?158 C→T mutation looked like intermediate. 4. RDB method we used for β-thal genotyping was rapid, reliable and easy to be practice. It could detect several kind mutations in one time hybridization and without using radioactive isotope.