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Biomedical subjects

V Thonglairuam

Publications and source records attributed to V Thonglairuam.

6 recordsLinked to original sources

The molecular basis of AE-Bart's disease.

AE-Bart's disease is a thalassemia intermedia resulting from the interaction between alpha-thalassemia and heterozygous Hb E. In this study we analyzed the alpha-globin genes of 25 patients designated as AE-Bart's disease by starch gel electrophoresis. Twenty-one cases had Hb Constant Spring in addition to Hbs E + A + Bart's, and the remaining four cases had only Hbs E + A + Bart's. DNA mapping revealed the alpha-globin genotype of alpha-thalassemia-1/alpha-thalassemia-2 in four patients who had Hbs E + A + Bart's, whereas the alpha genotype of the remainder is alpha-thalassemia-1/nondeletion alpha-thalassemia. The nondeletion alpha-thalassemia is Hb Constant Spring as indicated by starch gel electrophoresis. Hematologic data and hemoglobin analysis showed that Constant Spring-AE-Bart's disease is a more severe clinical syndrome than AE-Bart's disease.

Adolescent↗

Laboratory diagnosis for thalassemia.

Thalassemia is one of the common genetic disorders worldwide. alpha-thalassemia, beta-thalassemia, Hb E and Hb Constant Spring are common mutations found in S E Asia. The diagnoses of thalassemia and some abnormal hemoglobin carriers are very crucial for the identification of a high risk couple who will need further investigation of prenatal diagnosis. Determination of any thalassemic disease such as Hb H disease, homozygous beta-thalassemia, beta-thalassemia/Hb E can be carried out easily from the clinical findings, changes in hematologic data and hemoglobin electrophoresis. But the diagnoses of thalassemia carriers are cumbersome and sometimes need very sophisticated techniques of in vitro protein synthesis and DNA analysis. In this paper we review the laboratory methods and strategies for the diagnosis of thalassemia and abnormal hemoglobin commonly found in S E Asia.

Clinical Laboratory Techniques↗

Hematologic changes in alpha-thalassemia.

Alpha-thalassemia is very common in Thailand. Interaction of the different types of alpha-thalassemia can lead to many alpha-thalassemia syndromes. In this study the authors compare the hematologic data of subjects with various alpha-thalassemia phenotypes. Designation of the genotypes was based on family study and DNA mapping. The results show that there are equivocal hematologic findings among those who have similar molecular defects, i.e., alpha-thalassemia-2 and hemoglobin (Hb) Constant Spring heterozygotes: alpha-thalassemia 1, homozygous alpha-thalassemia 2, and alpha-thalassemia 2/Hb Constant Spring. The severity of these alpha-thalassemia syndromes correlates with the alpha-globin gene expression calculated from the finding of Liebhaber (Liebhaber SA, et al. J Biol Chem 1986; 261:15327-15333).

DNA↗

EF Bart's disease: interaction of the abnormal alpha- and beta-globin genes.

EF Bart's disease is an uncommon form of thalassaemia intermedia resulting from the co-inheritance of alpha-thalassaemia and haemoglobin E in the same subject. Starch-gel electrophoresis revealed two phenotypes in 19 patients with EF Bart's. 16 patients had Hbs CS + E + F + Bart's and the remainder had Hbs E + F + Bart's. DNA mapping and haemoglobin electrophoresis indicated that there are four genotypes, involving 5 abnormal globin genes, responsible for this thalassaemia syndrome.

Adolescent↗

Alpha-thalassemia in Thailand.

The alpha-thalassemia syndromes are remarkable both for their phenotypic diversity and for their different clinical severity. They are associated with variable degrees of alpha-chain deficits; the clinical manifestations range from asymptomatic cases with normal hematologic findings to the totally lethal Hb Bart's hydrops fetalis syndrome. Recent molecular biology studies have clarified the defects in these alpha-thalassemia syndromes around the world. This paper describes the alpha-thalassemias in Thailand, and covers the types, molecular defects, incidence of each genotype, and their phenotypic expression.

Fetal Blood↗

Beta-thalassemia associated with alpha-thalassemia in Thailand.

In Thailand alpha-thalassemia (thal), beta-thal, hemoglobin (Hb) E and Hb Constant Spring (Hb CS) are prevalent. The incidences are 20-30% for alpha-thal (3.5% for alpha-thal-1 and 16% for alpha-thal-2), 3-9% for beta-thal, up to 54% for Hb E and nearly 8% for Hb CS. Different combinations of these genes result in a spectrum of thalassemia syndromes ranging in severity from asymptomatic to intrauterine death. From the known gene frequencies the numbers of thalassemic patients per generation (total population of 50 million) are as follows: Hb Bart's hydrops fetalis 20,000; homozygous beta-thal 31,250; beta-thal/Hb E disease 162,500; Hb H disease (two genotypes) 200,000, making a total of 413,750. In addition, individuals may carry more than two of the abnormal genes leading to complex thalassemia syndromes such as alpha beta-thal, AE-Bart's and EF-Bart's diseases.

Gene Frequency↗