β-Hemoglobinopathies in the Lao People's Democratic Republic: Molecular diagnostics and implication for a prevention and control program

Introduction A high frequency of beta-thalassemia in Lao People's Democratic Republic necessitates the importance of complete molecular data before a prevention and control program could be established. Limited data are available for Lao PDR. We have now reported an extended information on the molecular basis of beta-hemoglobinopathies in this population. Methods The study was done on 519 unrelated Laos subjects requested for thalassemia investigation. Hematological data were recorded. Hb profiles were obtained using a capillary electrophoresis system. alpha-And beta-globin genotyping was performed using PCR and related techniques. Results Among the 519 subjects, 287 (55.3%) were found to carry beta-hemoglobinopathies based on Hb and DNA analyses. These included Hb E carriers (n = 135), homozygous Hb E (n = 47), beta-thalassemia carriers (n = 70), Hb E-beta-thalassemia (n = 25), homozygous beta-thalassemia (n = 4), heterozygous delta beta(0)-thalassemia (n = 2), and carriers of the beta-Hb variant (n = 3). Mutation analysis identified in addition to the Hb E, 8 different beta-thalassemia mutations including codon 17 (A-T), codons 41/42 (-TTCT), NT-28 (A-G), codons 71/72 (+A), IVS1-1 (G-T), 3.4 kb deletion, an initiation codon (T-G) and IVS2-654 (C-T). Two delta beta(0)-thalassemia carriers (12.6 kb deletion) and three subjects with Hb Hope (beta(136GGT-GAT)) were identified. Hematological features associated with these beta-hemoglobinopathies were presented. Conclusion beta-hemoglobinopathies in the Laos population is heterogeneous. This information is relevant for setting up a molecular diagnostics and can provide a basis for genetic counseling and enable prenatal diagnosis.