Molecular Heterogeneity of Thalassemia among Pregnant Laotian Women

Abstract

Background and Aims: A pilot screening program for thalassemia was initiated in the Lao People's Democratic Republic. This study aimed to describe the genotype diversity and hematologic features of thalassemia among the participating pregnant women. Methods: Blood samples of 411 pregnant Laotian women were collected. Hemoglobin (Hb) profiles were determined using a capillary zone electrophoresis system. Mutations of α- and β-globin genes were investigated using a polymerase chain reaction and related techniques. Results: As many as 26 different thalassemia genotypes including non-transfusion-dependent thalassemia, i.e. Hb E-β-thalassemia, Hb H, and EA Bart's diseases, were identified. A variety of phenotypic expressions of hematologic features and Hb profiles were observed, including an unusual phenotype of Hb E-β⁰ thalassemia with 89.1% Hb E, 1.6% Hb F, and 9.3% Hb A₂. Conclusions: The remarkable genotype-phenotype diversity indicates a need for careful laboratory interpretation in order to provide appropriate genetic counseling and care to the Laotian population.

Thalassemia and hemoglobinopathies in an ethnic minority group in Central Vietnam: implications to health burden and relationship between two ethnic minority groups

“…A marked reduction in MCV and MCH with mild anemia was observed in all forms of Hb E homozygotes. These hematologic changes were consistent with our previous studies Fucharoen et al 2004Fucharoen et al , 2006Savongsy et al 2008;Wongprachum et al 2016). Based on hematological parameters reported here, anemia seems not to be a major health burden in this minority group.…”

“…However, such cases appear to be rare. Based on our data collected independently from several communities Sanchaisuriya et al 2006;Savongsy et al 2008;Panomai et al 2010;Tritipsombut et al 2012;Wongprachum et al 2016), only 0.09% (2/2329) of individuals with normal MCV had elevated Hb A 2 . Nonetheless, our study provides evidence supporting the remarkably high Hb CS in ethnic minority groups in Central Vietnam.…”

Molecular prevalence of thalassemia and hemoglobinopathies among the Lao Loum Group in the Lao People’s Democratic Republic

“…Confirming previous data, our results demonstrate that thalassemias and hemoglobinopathies are highly prevalent and heterogeneous in the Lao population, with over 20 different genotypes being identified. The genotype and pattern of thalassemia genes detected in this study are similar to those reported in pregnant women . The results of this work indicate that thalassemias and hemoglobinopathies are a serious public health problem in the Lao PDR.…”

“…The interaction of these three forms of thalassemia may lead to a high prevalence of severe thalassemia syndrome, including the homozygous α 0 , homozygous β 0 , and β‐thalassemia/HbE types, which may affect public health in this community. Based on gene frequency analysis, we and previous authors found that the frequency of ‐‐ SEA /αα is more prevalent than that of the ‐α 3.7 /αα deletion in the Lao population. This α‐thalassemia frequency differs from those reported in neighboring South East Asian countries, including Vietnam, Thailand, and Cambodia, which show a higher frequency of the –α 3.7 deletion.…”

“…Epidemiological data on thalassemias and hemoglobinopathies in the Lao PDR population are currently only available from a few studies . It has been documented in Lao pregnant women in the Lao population that the prevalence of thalassemias and hemoglobinopathies is high . The prevalence observed in previous studies was primarily determined from the overall Lao population, and more collective data are needed.…”