Present address: Faculty of Medicine, Talagolla Road, Ragama, Sri Lanka.
The molecular basis for the thalassaemias in Sri Lanka
Article first published online: 16 MAY 2003
British Journal of Haematology
Volume 121, Issue 4, pages 662–671, May 2003
How to Cite
Fisher, C. A., Premawardhena, A., De Silva, S., Perera, G., Rajapaksa, S., Olivieri, N. A., Old, J. M., Weatherall, D. J. and the Sri Lanka Thalassaemia Study Group (2003), The molecular basis for the thalassaemias in Sri Lanka. British Journal of Haematology, 121: 662–671. doi: 10.1046/j.1365-2141.2003.04346.x
- Issue published online: 16 MAY 2003
- Article first published online: 16 MAY 2003
- Received 29 October 2002; accepted for publication 23 January 2003
- Sri Lanka
Summary. The β-globin gene mutations and the α-globin genes of 620 patients with the phenotype of severe to moderate thalassaemia from seven centres in Sri Lanka were analysed. Twenty-four β-globin gene mutations were identified, three accounting for 84·5% of the 1240 alleles studied: IVSI-5 (GC) 56·2%; IVSI-1 (GA) 15·2%; and haemoglobin E (codon (CD)26 GAGGAA) 13·1%. Three new mutations were found; a 13-bp deletion removing the last nucleotide in CD6 to CD10 inclusively, IVSI-129 (AC) in the consensus splice site, and a frame shift, CD55 (–A). The allele frequency of α+ thalassaemia was 6·5% and 1·1% for -α3·7 and -α4·2 deletions respectively. Non-deletion α-thalassaemia was not observed. Triplicate or quadruplicate α-globin genes were unusually common. In 1·5% of cases it was impossible to identify β-thalassaemia alleles, but in Kurunegala detailed family studies led to an explanation for the severe thalassaemia phenotype in every case, including a previously unreported instance of homozygosity for a quadruplicated α-globin gene together with β-thalassaemia trait. These findings have implications for the control of thalassaemia in high-frequency populations with complex ethnic histories.