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Background: Thalassemia is one of the most common single gene disorders worldwide with hundreds of mutations involving beta (β)-globin gene alone. Nevertheless, each ethnic population has its own unique type of mutations. The aim of this study is to characterize types of β-globin gene mutations among β-thalassemia patients in a teaching hospital; Hospital Universiti Sains Malaysia, Kubang Kerian, Kelantan, Malaysia.
Methods: Hematological profile for each patient was studied, and this was followed by screening and characterizations of β-globin mutations using multiplex amplification-refractory mutation system (ARMS)-PCR. In addition, direct DNA sequencing was also performed for the selected number of samples. Multiplex ARMS-PCR was carried out on 102 patient samples taken from three different ethnic groups: Malays, Chinese and Thais.
Results: This study finding indicated that majority of the patients were found to be heterozygous for Hb E (47.5%), heterozygous for β-thalassemia (31.3%) and homozygous for Hb E (7.5%). Heterozygous Hb Malay and compound heterozygous β-thalassemia/Hb E were observed at the equivalent frequency of 5.0%. Other genotypes include compound heterozygous β-thalassemia/ Hb Malay and compound heterozygous Hb E/ Hb Malay. However, 22 cases remain uncharacterized. Overall, 12 types of mutations were successfully identified which were depicted as 16 different genotypes. Cd 26 (G-A) mutation was found to be the most observed anomaly in this study.
Conclusion: In conclusion, together with complete red cell indices as well as information on ethnic background, the multiplex ARMS-PCR can be an effective tool in dissecting specific regional mutations of the β-globin gene particularly in multi-ethnic populations of Malaysia.