Mutational analysis of hemoglobin genes and functional characterization of detected variants, through in-silico analysis, in Pakistani beta-thalassemia major patients (original) (raw)
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Mutational Studies of Gene HBB in β-Thalassemia Patients from Balochistan, Pakistan
Current Trends in OMICS, 2021
Thalassemia is a hereditary blood disorder. It occurs due to two mutations in the HBB gene located on chromosome 11. This gene has 1606 base pairs and contains three exons. Moreover, HBB gene codes for β globin protein have been identified to posses 868 mutations, which comprise point mutation, insertion, deletion, and gene arrangement. In β thalassemia major, both alleles are mutated and no β chain is synthesized. In this study, three human families with thalassemia were selectedfrom different areas of Balochistan. For DNA extraction and estimation, 5 ml blood samples were extracted intravenously from the affected individuals, their normal siblings, and parents in 15ml falcon tubes containing 200μl EDTA. Primer sequences were designed on primer 3 for the mutational analysis of the HBB gene. Since the gene has a total of three exons and two introns, three primers, namely HBBX1, HBBX2 and HBBX3, were designed. These primers were used to amplify the HBB gene responsible for β thalasse...
Orphanet Journal of Rare Diseases
Background: ß-thalassemia is one of the most common inherited blood disorders in the world and a major deterrent to the public health of Bangladesh. The management of thalassemia patients requires lifelong frequent blood transfusion and the available treatment options are unsatisfactory. A national policy on thalassemia prevention is mandatory in Bangladesh. However, precise and up-to-date information on the frequency of ß-thalassemia carriers are missing due to lack of accurate diagnostic approaches, limited access to information and absence of national screening program. This study aims to determine the nationwide carrier frequency of hemoglobin E (HbE) and βthalassemia and mutation spectrum among the carriers using molecular, hematological and biochemical methods. Methods: The study enrolled a total of 1877 individuals (60.1% male and 39.9% female) aged between 18 and 35 years. Total sample size and its division-wise breakdown were calculated in proportion to national and division-wise population. Venous blood was collected and subjected to CBC analysis and Hb-electrophoresis for each participant. Serum ferritin was measured to detect coexistence of iron deficiency anemia with thalassemia carrier. DNA-based High Resolution Melting (HRM) curve analysis was performed for confirmation of carrier status by mutation detection. Results: Of 11.89% (95% CI, 10.43-13.35) carriers of β-globin gene mutations, 8.68% (95% CI, 7.41-9.95) had HbE trait (ETT) and 2.24% (95% CI, 1.57-2.91) had beta-thalassemia trait (BTT). Among eight divisions, Rangpur had the highest carrier frequency of 27.1% (ETT-25%, BTT-2.1%), whereas Khulna had the lowest frequency of 4.2% (ETT-4.2% only). Moreover, αthalassemia, HbD trait, HbE disease, hereditary persistence of HbF were detected in 0.11, 0.16, 0.43 and 0.16% participants, respectively. HRM could identify two individuals with reported pathogenic mutations in both alleles who were erroneously interpreted as carriers by hematological indices. Finally, a total of nine different mutations including a novel mutation (c.151A > G) were detected in the β-globin gene. Conclusions: Since carrier frequency for both HbE and β-thalassemia is alarmingly high in Bangladesh, a nationwide awareness and prevention program should be made mandatory to halt the current deteriorating situations. Mutationbased confirmation is highly recommended for the inconclusive cases with conventional carrier screening methods to avoid any faulty detection of thalassemia carriers.
2015
Background: ‚-thalassemia is a heterogeneous group of inherited hematological disorder. Though the importance of mutations in the beta-globin gene causing ‚-thalassemia have been reported worldwide, no data are available from rural population of SouthWestern Maharashtra. Objective: In the present study we aimed to characterize the mutations in s-globin gene from s-thalassemia patients from rural areas of South-Western Maharashtra. Material and Methods: The patients were analyzed for the s-globin gene mutations included IVS I-1 (G-T), IVS I-5 (G-C), cd 71/72 (+A), cd 41/42 (-TTCT), codon (cd) 8/9 (+G), cd 17 (A-T), cd 95 (+A), cd 43 (-C), cd 41 (-C), cd 35 (C-A), cd 26 (G-T), cd 19 (A-G), cd 15 (-T), cd 27/28 (+C) and cd 14/15 (+G) with the help of Multiplexed Amplification Refractory Mutation SystemPolymerase Chain Reaction (MARMS-PCR). Results: Out of the common mutations studied the cd 71/72 (21.54%), cd 19 (13.7 %). cd 41/42 (9.68%) and cd 41 (9.6%) showed high prevalence followe...
Spectrum of Genetic Mutation in Beta Globin Gene in Various Type of Thalassaemia in Bangladesh
Haematology Journal of Bangladesh, 2021
Background: Hb-E/Beta thalassaemia is a congenital haemoglobin disorder which is a compound heterozygous state consists of qualitative disorder like Hb E variant & quantitative Hb disorder caused by genetic mutation of Beta chain. Objective: The aim of the study was to identify the beta gene mutation in Hb E/Beta thalassaemia. Method: A total of 32 diagnosed Hb E/Beta thalassaemia patients were included in this cross-sectional study from May 2019 to July 2020. Genetic analysis was done by sanger sequencing. Results: In this observational study, we found 13 different types of Beta gene mutations. Heterozygous for IVS 1-5(G>C) mutation was most frequent (53.1%). Conclusion: Genetic mutation is the confirmatory diagnosis for thalassaemia as well as one of the main factors for clinical expression. Mutation pattern also varies according to the geographical distribution. So, this study shows the frequently found mutation in Bangladesh and should carry out routinely to point out phenoty...
2021
Background: Hemoglobin E/β-thalassemia is a common inherited hemoglobin disorder among South Asian countries. The phenotypically diverse presentation of the disease is often attributed to coinheritance of β-globin (HBB) gene mutations. The current study described the phenotype and genetic basis of Hb E/β-thalassemia patients and assessed its relation with clinical severity.Methods: A total of 32 patients were included in this cross-sectional study. Cases were confirmed by using capillary hemoglobin electrophoresis or high-performance liquid chromatography. Those with positive findings were further analyzed with clinical information and ancestral data either from the interview or medical records. Data collection was confined to May 2019 and July 2020. Gene sequencing was performed using Sanger’s sequencing method for mutational analysis, and Mahidol scoring was used to grade clinical severity.Result: A total of 13 heterozygous mutations were identified in the HBB gene. Of all, IVS-1-...
2004
HbVar (http://globin.cse.psu.edu/globin/hbvar/) is a relational database developed by a multi-center academic effort to provide up-to-date and high quality information on the genomic sequence changes leading to hemoglobin variants and all types of thalassemia and hemoglobinopathies. Extensive information is recorded for each variant and mutation, including sequence alterations, biochemical and hematological effects, associated pathology, ethnic occurrence and references. In addition to the regular updates to entries, we report two signi®cant advances: (i) The frequencies for a large number of mutations causing b-thalassemia in at-risk populations have been extracted from the published literature and made available for the user to query upon. (ii) HbVar has been linked with the GALA (Genome Alignment and Annotation database, available at http://globin.cse.psu.edu/gala/) so that users can combine information on hemoglobin variants and thalassemia mutations with a wide spectrum of genomic data. It also expands the capacity to view and analyze the data, using tools within GALA and the University of California at Santa Cruz (UCSC) Genome Browser.
International Journal of Population Studies
Thalassemia is a dreadful heritable hemolytic disease, characterized by a genetic mutation in the hemoglobin subunit beta (HBB) gene. Mutation in HBB gene completely halts the production of the beta-globin protein, which leads to the defective production of functional hemoglobin. The prevalence of this disease is reported only in some specific geographical regions of India. Hence, the aim of this study was to screen the population of Garhwal for beta-thalassemia (β-thalassemia) and thus find out the prevalence in the inhabitants through molecular characterization. For this study, 4,081 individuals were considered, out of which only the ones with elevated HbA2 levels (64) were subjected to molecular characterization. Mutational studies were carried out for the five most common mutations prevalent in the Indian subcontinent, that is, IVS 1-5 G-C, IVS 1-1 G-T, Codon 41/42 (-TCTT), Codon 8/9, and 619 bp deletion. The present study reports a frequency of 0.5% for β-thalassemia mutations ...