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

Abstract

A high frequency of β-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 β-hemoglobinopathies in this population. 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. α-And β-globin genotyping was performed using PCR and related techniques. Among the 519 subjects, 287 (55.3%) were found to carry β-hemoglobinopathies based on Hb and DNA analyses. These included Hb E carriers (n=135), homozygous Hb E (n=47), β-thalassemia carriers (n=70), Hb E-β-thalassemia (n=25), homozygous β-thalassemia (n=4), heterozygous δβ0 -thalassemia (n=2), and carriers of the β-Hb variant (n=3). Mutation analysis identified in addition to the Hb E, 8 different β-thalassemia mutations including codon 17 (A-T), codons 41/42 (-TTCT), NT-28 (A-G), codons 71/72 (+A), IVS1-1 (G-T), 3.4kb deletion, an initiation codon (T-G) and IVS2-654 (C-T). Two δβ0 -thalassemia carriers (12.6kb deletion) and three subjects with Hb Hope (β136GGT-GAT ) were identified. Hematological features associated with these β-hemoglobinopathies were presented. β-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.