PubMed Health⌕ Search

Biomedical subjects

G Fucharoen

Publications and source records attributed to G Fucharoen.

32 records · Page 2Linked to original sources
PubMed1992

Molecular basis of beta thalassemia in the south of Thailand.

A total of 103 beta thalassemia genes from 78 children (45 with Hb E/beta thalassemia, 8 with beta thalassemia heterozygotes, and 25 with homozygous beta thalassemia) were analyzed using dot-blot hybridization of the polymerase chain reaction-amplified DNA and direct DNA sequencing. Nine mutations were characterized in 98/103 (95%) of beta thalassemia alleles, of which six (a 4 bp deletion in codons 41-42, a G-C transition at position 5 of IVS-1, A-G transition at codon 19, an A-T transition at codon 17, an A-G transition at position -28 upstream of the beta globin gene, a G-T transition at position 1 of IVS-1), accounted for 92%. The spectrum of beta thalassemia mutations in Chinese Thai is similar to that reported among the Chinese from other parts of the world. The distribution of beta thalassemia mutations in Muslim Thai is similar to that reported among Malaysians. The most common beta thalassemia mutation in Thai and Chinese Thai patients is the frameshift mutation at codons 41-42, in comparison with the Muslim Thai in whom the G-C transition at position 5 of the IVS-1 mutation predominates. The heterogeneity of molecular defects causing beta thalassemia should aid in the planning of a prenatal diagnosis program for beta thalassemia in the South of Thailand.

Alleles↗
PubMed1992

Molecular heterogeneity of beta-thalassemia in Thailand.

beta-Globin genes in 294 chromosomes of beta-thalassemia homozygotes and patients of beta-thalassemia/HbE in the northeast, the middle and the south of Thailand were analyzed by the PCR related techniques: dot blot hybridization, direct restriction assay, direct cloning and direct sequencing of the amplified DNA fragments. Twelve different mutations were detected at various frequencies. They are an A-G at-28, codon 19 (AAC-AGC), a G-T at IVS-1 nt1,a G-C at IVS-1 nt5, a C-T at IVS-2 nt654, a G addition in codons 8/9, a C deletion in codon 41, a 4 bp deletion in codons 41/42, an A addition in codons 71/72, an AAG-TAG in codon 17, a CAG-TAG in codon 26, a TAC-TAA in codon 35 and a 8 bp deletion in codons 123-125. We also developed allele specific-polymerase chain reaction to facilitate non-radioactive detection of the mutation. Origins and spread of mutations are speculated based on the results of determination of haplotypes and frameworks that are linked to the thalassemia alleles.

Base Sequence↗
PubMed1991

Double heterozygosity of the beta-Malay and a novel beta-thalassemia gene in a Thai patient.

The beta-globin genes from a Thai patient compound heterozygous for beta(+)- and beta zero-thalassemias were investigated. Amplification and DNA analysis of genomic DNA by the polymerase chain reaction procedure permitted the identification of the beta-Malay mutation (beta 19;AAC-AGC) in one allele and a novel beta zero-thalassemia mutation (41;TTC-TT) in another allele.

Base Sequence↗
PubMed1990

Molecular basis of HbE-beta-thalassemia and the origin of HbE in northeast Thailand: identification of one novel mutation using amplified DNA from buffy coat specimens.

Amplification of DNA via polymerase chain reaction directly from a small amount of a buffy coat fraction was used to study the molecular basis of HbE-beta-thalassemia in the northeastern Thai population. Eight different mutations including the new one causing a beta o-thalassemia phenotype were detected. This novel mutation is an amber mutation at codon 26, which occurs at the same position as that of HbE; the most common hemoglobin variant in Southeast Asian countries. A pitfall in detection of the HbE mutation by restriction enzyme analysis was pointed out and differential diagnosis of the HbE mutation and the novel one by using allele specific oligonucleotide probes were described. Analysis of polymorphic restriction sites in the beta-globin gene cluster containing the beta E gene revealed two previously undescribed haplotypes in the Southeast Asian populations, which provide evidence for the multiple origins of beta E gene in Southeast Asian populations.

Alleles↗
PubMed1990

Molecular heterogeneity of beta-thalassaemia in the Japanese: identification of two novel mutations.

Five unrelated Japanese beta-thalassaemia genes, from one homozygote and four heterozygotes, have been systematically characterized using DNA polymorphism analysis, polymerase chain reaction, dot-blot hybridization and direct sequencing of amplified genomic DNA. Four different molecular defects were observed on three different beta-globin gene frameworks. One of these, the A----G mutation in the TATA box, a previously described mutation, was detected by dot-blot hybridization in one homozygote and one heterozygote with the beta-globin gene of framework 2. The second mutation is a C----T substitution at position 654 of IVS-2, the mutation commonly found in Chinese, which was associated with the framework 1 gene. Another two mutations, both associated with framework 3 genes, are novel ones; an amber mutation in codon 90 (GAG to TAG) and a frameshift (+G) insertion in codon 54, both of which cause a beta 0-thalassaemia phenotype by premature termination of the beta-globin chain synthesis.

Adult↗
PubMed1990

A single nucleotide deletion in codon 123 of the beta-globin gene causes an inclusion body beta-thalassaemia trait: a novel elongated globin chain beta Makabe.

The beta-globin gene from a Japanese individual with an inclusion body beta-thalassaemia trait has been characterized by gene cloning and DNA sequencing. An adenine deletion was detected at the first position of codon 123 (ACCCC) of one allele whereas the other allele had a normal sequence. Heterozygosity for this mutation in the patient was confirmed by Southern blots of the genomic DNA digested with HphI, the recognition site of which is eliminated by this deletion. This one base deletion results in the shift of a reading frame in such a manner that the normal termination codon is out of phase. This frameshift mutation results in the synthesis of an elongated beta-globin chain with 10 extra amino acid residues and with an altered C-terminus. Analysis of labelled globin chains using CM-cellulose column chromatography failed to demonstrate any abnormal protein, thereby suggesting that the beta-globin chain variant is highly unstable and probably degrades rapidly after synthesis. This event will lead to an accumulation of free alpha-chains precipitating in the red blood cells and an inclusion body beta-thalassaemia phenotype would ensue.

Amino Acid Sequence↗
PubMed1990

Molecular characterization and nonradioactive detection of beta-thalassemia in Malaysia.

The spectrum of beta-thalassemia mutations in Malaysia has been determined in 45 beta-thalassemia chromosomes using dot blot hybridization of the polymerase chain reaction amplified DNA and direct DNA sequencing. Eleven different molecular defects, including those previously detected in Chinese, Asian Indians, and American blacks, and a novel frameshift mutation causing beta zero-thalassemia were detected. Since this novel mutation, a T deletion in codon 15 creates a new restriction site for EcoRII enzyme; the mutation could be detected by EcoRII digestion of the appropriate amplified fragment. The results of the present study provide additional information on the molecular heterogeneity of beta-thalassemia in this population. We also demonstrated the nonradioactive detection method of the beta-thalassemia mutation based upon the digoxigenin-labeled oligonucleotide probes.

Base Sequence↗
PubMed1989

A novel ochre mutation in the beta-thalassemia gene of a Thai. Identification by direct cloning of the entire beta-globin gene amplified using polymerase chain reactions.

The beta-globin genes from a Thai patient compound heterozygous for beta-thalassemia and HbE disease were investigated. The 3.0-kilobase fragment containing the entire beta-globin gene was amplified by polymerase chain reaction, using Taq DNA polymerase followed by direct cloning of the amplified product into plasmid DNA. Sequence analysis of the thalassemia gene revealed only one base change, a C-A transversion within codon for an amino acid 35. This new mutation creates a premature terminator, TAA, an ochre codon, and results in a beta 0-thalassemia phenotype. The same result was obtained when this mutation was analyzed using a conventional cloning technique, direct sequencing of the amplified product, and hybridization with allele-specific oligonucleotide probes. No misincorporation was detected in the sequence analysis of the 3.0-kilobase insert of five clones of the amplified products obtained from genomic DNA of a normal individual. This approach is a rapid and accurate method for molecular cloning of the beta-globin gene and also other genes, the partial nucleotide sequences of which are known.

Base Sequence↗
PubMed1989

Molecular basis of beta-thalassemia in Thailand: analysis of beta-thalassemia mutations using the polymerase chain reaction.

beta-Thalassemia mutations in 71 chromosomes of Thai patients from the northeast, the middle and the south of the country were investigated using dot blot hybridization of PCR (polymerase chain reaction)-amplified DNA with allele-specific oligonucleotide probes. Eight different known molecular defects were detected, at different frequencies. There was an amber mutation in codon 17, a C-T transversion at position 654 of IVS-2, a frameshift mutation between codons 71 and 72, an A-G transition at nucleotide -28 within the TATA box (known as Chinese mutations), a G-T transversion at position 1 of IVS-1 (an Indian mutation), a 4 bp deletion in codons 41/42 and a G-C transversion at position 5 of IVS-1 (described as both Chinese and Indian mutations) and a Thai original mutation, an ochre mutation in codon 35. Analysis of the three unknown alleles by DNA sequencing of the cloned DNA fragment amplified by PCR revealed an A-G substitution at the second position of the codon for amino acid 19 (AAC-AGC). The analytic approach used in the present study and the characteristic distribution of mutations in each region of Thailand will prove useful for setting up a prenatal diagnosis program.

Alleles↗
PubMed1989

Heterogeneity of the gamma-globin gene sequences in Japanese individuals: implication of gene conversion in generation of polymorphisms.

The linked fetal globin genes (the G gamma- and A gamma-globin genes) were cloned from Japanese individuals with three different haplotypes of the HindIII polymorphisms within the gamma-globin genes. Determination of nucleotide sequences of the segment spanning from IVS2 to the 3' flanking region of each gamma-globin gene revealed that nucleotide differences are located at 43 positions and a stretch of simple GT or GC sequences. Almost half of the nucleotide changes could be accounted for by gene conversion between the G gamma- and A gamma-globin genes. We found that gene conversion had created the SacI polymorphic site just downstream of the A gamma-globin coding region. Association of the SacI polymorphic site with the HindIII polymorphic site suggests that the region containing these two sites was derived from that of the linked G gamma-globin gene through a gene conversion event. The nucleotide sequences obtained here are identical to those of the Caucasoid fetal globin genes of the same haplotypes, with the exception of some sequence changes in the hot spots of mutations. These results indicate that the sequence heterogeneity of the gamma-globin genes can be classified into three major categories according to HindIII haplotypes. The possible mechanisms of generation of the heterogeneity of the gamma-globin gene sequences are discussed.

Base Sequence↗