RESUMO
ß-thalassemia is a serious public health problem in Sabah due to its high prevalence. This study aimed to investigate the effects of different types of ß-globin gene mutations, coinheritance with α-globin gene mutations, XmnI-Gγ, and rs368698783 polymorphisms on the ß-thalassemia phenotypes in Sabahan patients. A total of 111 patients were included in this study. The sociodemographic profile of the patients was collected using a semi-structured questionnaire, while clinical data were obtained from their medical records. Gap-PCR, ARMS-PCR, RFLP-PCR, and multiplex PCR were performed to detect ß- and α-globin gene mutations, as well as XmnI-Gγ and rs368698783 polymorphisms. Our data show that the high prevalence of ß-thalassemia in Sabah is not due to consanguineous marriages (5.4%). A total of six different ß-globin gene mutations were detected, with Filipino ß°-deletion being the most dominant (87.4%). There were 77.5% homozygous ß-thalassemia patients, 16.2% compound heterozygous ß-thalassemia patients, and 6.3% ß-thalassemia/Hb E patients. Further evaluation on compound heterozygous ß-thalassemia and ß-thalassemia/Hb E patients found no concomitant α-globin gene mutations and the rs368698783 polymorphism. Furthermore, the XmnI-Gγ (-/+) genotype did not demonstrate a strong impact on the disease phenotype, as only two of five patients in the compound heterozygous ß-thalassemia group and two of three patients in the ß-thalassemia/Hb E group had a moderate phenotype. Our findings indicate that the severity of the ß-thalassemia phenotypes is closely related to the type of ß-globin gene mutations but not to the XmnI-Gγ and rs368698783 polymorphisms.
