The spectrum of β‐thalassaemia mutations on the Indian subcontinent: the basis for prenatal diagnosis

Varawalla, Nermeen; Old, John; Sarkar, Rita; Venkatesan, Radha; Weatherall, D. J.

doi:10.1111/j.1365-2141.1991.tb04423.x

Cited by 217 publications

(136 citation statements)

References 24 publications

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“…In contrast, codon 26/HbE G3 A is very common in a large part of mainland Southeast Asia, from Burma in the west to Vietnam in the east, as well as in aboriginal Malays (1 ). In India, codon 8/9 ϩG; IVSI,1 G3 T; IVSI,5 G3 C; codon 41/42 ϪTTCT; and ⌬619bp together account for Ͼ90% of ␤-thalassemia mutations (1,6 ).…”

Section: Resultsmentioning

confidence: 99%

“…These include restriction fragment length polymorphism analysis (9 ), dot-blot hybridization with allele-specific oligonucleotides (10 -12 ), denaturing gradient gel electrophoresis (13,14 ), reverse dot-blot hybridization (15)(16)(17)(18), direct DNA sequencing (19 ), and amplification refractory mutation system (ARMS) 6 (20,21 ). More recently, fluorescence-based multiplex minisequencing followed by gel electrophoretic size separation has been used to simultaneously detect multiple mutations and other nucleotide variants (22)(23)(24).…”

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confidence: 99%

“…In these regions, Ͻ20 variations account for the overwhelming majority of ␤-thalassemia alleles. These include Ϫ29 A3 G; Ϫ28 A3 G; codon 0 T3 G; codon 8/9 ϩG; codon 17 A3 T; codon 19 A3 G; codon 26/HbE G3 A; codon 27/28 ϩC; IVSI,1 G3 T; IVSI,5 G3 C; codon 35 ϪC; codon 41/42 ϪTTCT; codon 43 G3 T; codon 71/72 ϩA; IVSII, 654 C3 T; and the ⌬619bp deletion (1,(3)(4)(5)(6)(7)(8). Three variants alone account for more than two-thirds of the ␤-thalassemias in the combined region; IVSI,5 G3 C (33%); codon 41/42 ϪTTCT (27%); and IVSI,1 G3 T (9%) (1 ).…”

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confidence: 99%

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Multiplex Minisequencing Screen for Common Southeast Asian and Indian β-Thalassemia Mutations

Wang¹,

Kham²,

Yeo³

et al. 2003

Clinical Chemistry

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Background: ␤-Thalassemia is endemic to many regions in Southeast Asia and India, and <20 ␤-globin gene mutations account for >90% of ␤-thalassemia alleles in these places. We describe a multiplex minisequencing assay to detect these common mutations. Methods: Gap-PCR was used to simultaneously amplify the ␤-globin gene from genomic DNA and to detect the ⌬619bp deletion mutation. Multiplex minisequencing was then performed on the amplified ␤-globin fragment to detect an additional 15 common Southeast Asian and Indian ␤-thalassemia mutations. Site-specific primers of different lengths were subjected to multiple rounds of annealing and single-nucleotide extension in the presence of thermostable DNA polymerase and the four dideoxynucleotides, each labeled with a different fluorophore. Minisequencing products were separated and detected by capillary electrophoresis, followed by automated genotyping. The optimized assay was subjected to a double-blind validation analysis of 89 ␤-thalassemia and wild-type DNA samples of known genotype. Results: Homozygous wild-type or mutant DNA samples produced electropherograms containing only a single colored peak for each mutation site, whereas samples heterozygous for a specific mutation displayed two different-colored peaks for that mutation site. Samples were automatically genotyped based on color and posi-

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Section: Resultsmentioning

confidence: 99%

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confidence: 99%

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confidence: 99%

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Multiplex Minisequencing Screen for Common Southeast Asian and Indian β-Thalassemia Mutations

Wang¹,

Kham²,

Yeo³

et al. 2003

Clinical Chemistry

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“…Normally ␤-thalassemia trait in India is 3.3% with 1-2 per 1,000 couples being at risk of having an affected offspring each year, leading to a high societal burden [2]. As the ethnic composition of the Indian popu-lation is heterogeneous [3], each region of the country has its own distinct set and frequency of ␤-thalassemia mutations [4]. Orkin et al (5, Fig.…”

Section: Introductionmentioning

confidence: 99%

Spectrum of β‐thalassemia mutations and their association with allelic sequence polymorphisms at the β‐globin gene cluster in an eastern Indian population

et al. 2002

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In this report, the spectrum of ␤-thalassemia mutations and genotype-to-phenotype correlations were defined in large number of patients (␤-thalassemia carriers and major) with varying disease severity in an Eastern Indian population mainly from the state of West Bengal. The five most common ␤-thalassemia mutations were detected, which included IVS1-5 (G➝C), codon 15 (G➝A), codon 26 (G➝A), codon 30 (G➝C), and codon 41/42 (−TCTT). These accounted for 85% in 80 ␤-thalassemic alleles deciphered from 56 patients, including ␤-thalassemia major and carriers, and 15% of alleles remained uncharacterized in these patients. Expression of the human ␤-globin gene is regulated by an array of cis-acting DNA elements, including five DNase I hypersensitive sites (HSs) in the locus control region (LCR), promoters that incorporate certain silencer elements, and enhancers at 3 of the ␤-globin gene. For detailed studies and to understand the molecular basis of ␤-thalassemia, we studied two groups of subjects: a group of 12 patients from four families having ␤-thalassemia major and carrier phenotype and a control group of 26 healthy individuals. In these two groups, we examined portions of the ␤-globin gene locus control region HSs 1, 2, 3, and 4, which included the (CA) x (TA) y repeat motif, the (AT) x N y (AT) z repeat motif, the inverted repeat sequence TGGGGACCCCA, the promoter region of the G ␥-globin gene, an (AT) x (T) y repeat 5 of the silencer region, and the ␤-globin gene and its 3 flanking region. We investigated the allelic sequence polymorphisms in these regions and their association with the ␤-thalassemia mutations to know the possible genotype-phenotype relationship in ␤-thalassemia patients. An analysis of cisacting regulatory regions showed varied sequence haplotypes associated with some frequent ␤-thalassemia mutations in this Eastern Indian population. Am.

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“…The ARMS-PCR technique is a popular technique to identify the known b-thalassemia mutations [16,17]. In this study, we have successfully devised a multiplex ARMS-PCR system for the detection of b-thalassemia mutations commonly found in AfricanAmericans and Asians, including those of Chinese, Taiwanese, Southeast Asian, and Asian Indian descent.…”

Section: Discussionmentioning

confidence: 99%

Molecular genetic confirmatory testing from newborn screening samples for the common African‐American, Asian Indian, Southeast Asian, and Chinese β‐thalassemia mutations

et al. 2005

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b-Thalassemia is a serious health problem in the United States, especially in California, due to increased Asian immigration. Neonatal screening by using high-performance liquid chromatography (HPLC) or isoelectric focusing (IEF) may lead to confusion due to interactions of various hemoglobinopathies with b-thalassemia. Our purpose was to develop single-tube multiplexed PCR assays using original neonatal screening specimens to identify the mutations responsible for b-thalassemia in order to expedite diagnostic confirmation. Primers were designed for two to six common ethnic-specific mutations using the amplification refractory mutation system (ARMS). This multiplex ARMS approach was standardized using DNA samples with known mutations for b-thalassemia in those of Asian (Southeast Asian, Chinese, and Asian Indian) and African-American descent. Specimens from African-American neonates were tested for two mutations (À88 and À29); Asian Indians for five mutations (IVSI-1, IVSI-5, codons (Cd) 41/42, Cd 8/9, and 619-bp deletion); Chinese, Taiwanese, and Southeast Asians for seven mutations (Cd 41/42, Cd 17, À28, IVSII-654, Cd 71/72, IVSI-5, and IVSI-1). We identified each of these b-thalassemia mutations in multiplexed ARMS from positive control samples. We tested 25 anonymized dried blood specimens from neonates who had been diagnosed with b-thalassemia and who also belonged to these ethnic groups. We detected a mutation specific to the neonate's ethnic group using the ARMS approach in nearly all specimens, and the results were confirmed by sequencing. Multiplexed ARMS for ethnic-specific b-thalassemia mutations from the original newborn screening dried blood specimens is a rapid and efficient approach for diagnostic confirmation. Am.

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The spectrum of β‐thalassaemia mutations on the Indian subcontinent: the basis for prenatal diagnosis

Cited by 217 publications

References 24 publications

Multiplex Minisequencing Screen for Common Southeast Asian and Indian β-Thalassemia Mutations

Multiplex Minisequencing Screen for Common Southeast Asian and Indian β-Thalassemia Mutations

Spectrum of β‐thalassemia mutations and their association with allelic sequence polymorphisms at the β‐globin gene cluster in an eastern Indian population

Molecular genetic confirmatory testing from newborn screening samples for the common African‐American, Asian Indian, Southeast Asian, and Chinese β‐thalassemia mutations

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