Molecular study and genotype/phenotype correlation of β thalassemia in Malaysia

Summary Introduction: To study the s-gene mutations spectrum, the genotype/phenotype correlation, the modulatory effect of co-inherited factors such as α-gene mutations and of Xmn1 polymorphism in a large cohort of Malaysian patients. Methods: A total of 264 cases clinically diagnosed as Thalassemia major (TM) (111), Thalassemia intermedia (21), HbE-β Thalassemia (131), and 1 HbE homozygous were studied. The detection of α and s gene mutations and characterization of Xmn1 polymorphism were performed by multiplex PCR, amplification refractory mutation system (ARMS), DNA sequencing, and restriction fragment length polymorphism (RFLP)-PCR. Results: A total of 19 s Thalassemia mutations were characterized. CD26 and CD41/42 were the most common found in the Malay and Chinese population, respectively. The sensitivity of the clinical diagnosis for β TM, thalassemia intermedia, and HbE/β thalassemia was 94.0%, 15.2%, and 89.2%, respectively. Patients with Xmn1 heterozygosity [+/−] required less frequent transfusion compared with those without the polymorphism. Co-inheritance of α-thalassemia alleviates the severity of HbE-β thalassemia in our cohort. Conclusion: Molecular analysis should be used for a better diagnosis and management of β thalassemia.