Biomedical subjects
P Winichagoon
Publications and source records attributed to P Winichagoon.
Thai G gamma (A gamma delta beta)zero-thalassemia and its interaction with a single gamma-globin gene on a chromosome carrying beta zero-thalassemia.
Clinical manifestations and hematologic data of thalassemia intermedia were observed in three siblings of a Thai family. Analyses of the hemoglobin of their parents and other siblings indicated that they inherited a delta beta-thalassemia gene from the father and a beta zero thalassemia gene from the mother. Globin gene mapping confirmed that they carry two abnormal beta-globin gene complexes. On one chromosome more than 70 kb of DNA was removed which resulted in G gamma (A gamma delta beta)zero-thalassemia. The deletion started at the Hind III site located just 3' to the G gamma gene, and extended downstream to a region recognized by the p3'N 2.8R probe which is located more than 45 kb from the 3' end of the beta gene. The other chromosome carried a beta zero thalassemia gene, and a 5 kb deletion between the G gamma and A gamma genes which produced a hybrid -GA gamma- gene. A synthetic oligonucleotide probe showed that this beta zero thalassemia arose from a C----T mutation at position 654 of IVS-II in the beta-globin gene.
The molecular basis of beta-thalassemia in Thailand: application to prenatal diagnosis.
To enable the prenatal diagnosis of beta-thalassemia by direct detection of the mutant beta-globin genes, we have determined the spectrum of mutations causing this disease in Thailand. The techniques employed included a combination of synthetic oligonucleotide probe hybridization, direct sequencing of genomic DNA enzymatically amplified by the polymerase chain reaction, and cloning and sequencing of the beta-globin genes. A total of 116 beta-thalassemia genes from 78 Hb E/beta-thalassemia patients and from 19 homozygous beta-thalassemia patients were analyzed, and the mutation was characterized in 112/116 (97%) of them. Eleven mutations were found, of which four (-CTTT in codon 41/42, AAG----TAG in codon 17, C----T in position 654 of the IVS-2 region, and A----G in position -28 upstream of the beta-globin gene) accounted for 83%; two previously undescribed mutations have been identified. The spectrum of beta-thalassemia mutations is similar to that reported among the Chinese. However, within the Thai population itself, patients with homozygous beta-thalassemia show a wider spread of mutations in comparison with the Hb E/beta-thalassemia group, in whom the frameshift 41/42 mutation predominates at a frequency of 62%. This difference in distribution may reflect the difference in ethnic origin of the two groups. Characterization of these mutations should aid the planning of a prenatal diagnosis program for beta-thalassemia in Thailand.
Molecular basis of beta (0)-thalassemia/HbE disease in Thailand.
The molecular basis of beta(0)-thalassemia/HbE disease in 30 Thai patients was investigated using DNA amplification and dot-blot hybridization with a number of allele specific oligonucleotide probes. The mutations identified were 17 cases of 4 base-pair deletion at codons 41-42, 4 cases of amber mutation at codon 17, and one case each of an ochre mutation at codon 35, a single base substitution at position 5 of IVS-1, and a single base substitution at position 654 of IVS-2.
Detection of beta-thalassemia and hemoglobin E genes in Thai by a DNA amplification technique.
Enzymatic DNA amplification and polyacrylamide gel electrophoresis, which demonstrate different sizes of DNA fragments, were used to detect the common mutations causing beta-thalassemia and hemoglobin (Hb) E in Thai people. The 4-bp deletion at codons 41 and 42 can be detected directly by polyacrylamide gel electrophoresis and ethidium bromide staining. Whereas the nonsense mutations at codon 17 (AAG----TAG) and Hb E (GAG----AAG at codon 26) were detected after digestion of the amplified DNA with the enzymes MaeI and MnlI, respectively.
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.
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.
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).
Characterization of two deletions that remove the entire human zeta-alpha globin gene complex (- -THAI and - -FIL).
We have fully characterized two alpha thalassaemia mutants that occur in Southeast Asia, - -THAI and - -FIL. Each mutant is due to a deletion that removes the entire zeta-alpha-globin gene complex. Localization of the 5' breakpoints described here, allows the identification of unique fragments that are specific for each of the two mutations. This information can be used to assess the frequency of these mutants in Southeast Asia and will be of value in prenatal testing for alpha thalassaemia in this area.
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.
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.
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.
Different severity of homozygous beta-thalassemia among siblings.
Different degrees of severity of anemia are presented in three siblings with homozygous beta-thalassemia. II-1, the most severely affected one, is splenectomized and needs frequent blood transfusion, while II-4 has mild anemia and never receives transfusion. II-3 has moderate anemia and mild jaundice and hepatosplenomegaly. Restriction endonuclease DNA mapping revealed the alpha-thalassemia-2 genes in II-3 and II-4 and no alpha-thalassemia-2 haplotype in II-1. Furthermore, II-4, who is mildly affected, is homozygous for alpha-thalassemia-2 whereas II-3 is an alpha-thalassemia-2 heterozygote. These observations indicate that concomitant inheritance of alpha-thalassemia can decrease the severity of beta-thalassemia.
The integration of psychosocial components in nutrition education in northeastern Thai villages.
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Hemoglobinopathies in Southeast Asia.
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Identification of Hb Lepore-Washington-Boston in association with Hb E [beta 26(B8)Glu----Lys] in a Thai female.
The proposita was a Thai female showing signs of a mild anemia (Hb: 11.4 g/dl; RBC: 4.91 X 10(6)/mm3; reticulocytes: 2.4%; MCV: 70 fl; MCHC: 23.3 g/dl). Hemoglobins were isolated by DEAE-cellulose chromatography in the following relative amounts: Hb E + Hb A2 = 53%; Hb F0 = 30.0%; Hb delta beta-Lepore = 12.7%; Hb F1 = 4.3%. The beta E and delta beta-Lepore chains were isolated by CM-cellulose chromatography and were subjected to tryptic peptide mapping on paper in comparison to normal beta A chains. Amino acid analysis of selected peptides permitted unambiguous identification of the abnormal hemoglobins as Hb E [beta 26(B8)Glu----Lys] and Hb Lepore-Washington-Boston, which has a delta chain sequence for residues 1-87, and a beta chain sequence for residues 116-146. The presence of a Lepore hemoglobin was further confirmed by Pst I digestion of the proposita's DNA. The association of the two hemoglobin variants gave rise to elevated levels of Hb F.
Alpha-mRNA level in the two types of Hb H disease.
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Studies of hemoglobin Bart and deletion of alpha-globin genes from cord blood in Thailand.
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