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Sinha S, Dutta AK, Bhattacharya P, Bhattacharya S, Das MK. Spectrum of Rare and Novel Indel Mutations Responsible for β Thalassemia in Eastern India. Indian J Clin Biochem 2024; 39:207-213. [PMID: 38577149 PMCID: PMC10987419 DOI: 10.1007/s12291-022-01098-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Accepted: 11/06/2022] [Indexed: 01/04/2023]
Abstract
There is limited data available regarding the clinical utility of routine molecular diagnosis of β Thalassaemia in addition to HPLC-based screening in low resource settings. The current study highlights the caveats of an HPLC-based screening compared to the inclusion of genetic confirmation as a second-tier test and its implications in terms of genotype-phenotype correlation. A prospective, institution-based, observational study was conducted at the Department of Paediatric Medicine, including 103 children aged up to 12 years. Five common mutations for β Thalassemia and the HbE mutation in the HBB gene were tested by a two-tiered approach using multiplex ARMS PCR and PCR RFLP methods respectively. Sanger sequencing of all three exons of the HBB gene was performed in all negative cases. Sequencing revealed many rare pathogenic mutations like c.316-106 C > G (dbSNP: 34,690,599); Hb Kairouan (c.92G > C); c.33 C > A (dbSNP rs35799536); c.47G > A (dbSNP rs63750783); c.51delC (HbVar ID 799); c.[93-2 A > C] and c.118 C > T (HbVar ID 845). We detected a novel Pathogenic M_000518.5(HBB):c.164_168delinsGGCATCA (p.Val55fs) mutation in a heterozygous state which was reported in the ClinVar database with accession ID VCV000590977.2. We also encountered several cases of silent carrier on HPLC and de novo occurrence of mutation. We conclude that the multiplex touchdown ARMS PCR methodology employed in the present study provides a low-cost solution for molecular diagnostics of Β Thalassaemia. The problem of silent carriers in HPLC is significant enough to rethink if we need supplemental genetic testing in the couple when one of the partners is a carrier. Supplementary Information The online version contains supplementary material available at 10.1007/s12291-022-01098-w.
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Affiliation(s)
- Sajan Sinha
- Department of Paediatrics, IPGME&R and SSKM Hospital, Kolkata, India
| | - Atanu Kumar Dutta
- Department of Biochemistry, All India Institute of Medical Sciences, Second Floor, Medical College Block, NH - 34 Connector Basantapur, Saguna, 741245 Kalyani, West Bengal India
| | | | | | - Mrinal Kanti Das
- Department of Paediatrics, IPGME&R and SSKM Hospital, Kolkata, India
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Pines M, Sheth S. Clinical Classification, Screening, and Diagnosis in Beta-Thalassemia and Hemoglobin E/Beta-Thalassemia. Hematol Oncol Clin North Am 2023; 37:313-325. [PMID: 36907605 DOI: 10.1016/j.hoc.2022.12.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/12/2023]
Abstract
This article reviews the classification of beta-thalassemia syndromes, correlating clinical severity and genotype in the earlier classification, and broadening it recently based on clinical severity and transfusion status. The classification is dynamic, and individuals may progress from transfusion-independent to transfusion-dependent. Early and accurate diagnosis prevents delays in instituting treatment and comprehensive care, and precludes inappropriate and potentially harmful interventions. Screening can inform risk in an individual and subsequent generations when partners may be carriers as well. This article discusses the rationale for screening of the at-risk population. In the developed world, a more precise genetic diagnosis must be considered.
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Affiliation(s)
- Morgan Pines
- Division of Pediatric Hematology/Oncology, Department of Pediatrics, Weill Cornell Medicine, P-695, 525 East 68th Street, New York, NY 10065, USA; Department of Pediatrics, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, H1117A, New York, NY 10065, USA
| | - Sujit Sheth
- Division of Pediatric Hematology/Oncology, Department of Pediatrics, Weill Cornell Medicine, P-695, 525 East 68th Street, New York, NY 10065, USA.
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Mettananda S. Genetic and Epigenetic Therapies for β-Thalassaemia by Altering the Expression of α-Globin Gene. Front Genome Ed 2021; 3:752278. [PMID: 34713267 PMCID: PMC8525347 DOI: 10.3389/fgeed.2021.752278] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 09/20/2021] [Indexed: 01/19/2023] Open
Abstract
β-Thalassaemia is caused by over 300 mutations in and around the β-globin gene that lead to impaired synthesis of β-globin. The expression of α-globin continues normally, resulting in an excess of α-globin chains within red blood cells and their precursors. These unpaired α-globin chains form unstable α-hemichromes that trigger cascades of events to generate reactive oxygen species, leading to ineffective erythropoiesis and haemolysis in patients with β-thalassaemia. The clinical genetic data reported over several decades have demonstrated how the coinheritance of α-thalassaemia ameliorates the disease phenotype of β-thalassaemia. Thus, it is evident that down-regulation of the α-globin gene expression in patients with β-thalassaemia could ameliorate or even cure β-thalassaemia. Over the last few years, significant progress has been made in utilising this pathway to devise a cure for β-thalassaemia. Most research has been done to alter the epigenetic landscape of the α-globin locus or the well-characterised distant enhancers of α-globin. In vitro, pre-clinical studies on primary human erythroid cells have unveiled inhibition of histone lysine demethylation and histone deacetylation as potential targets to achieve selective downregulation of α-globin through epigenetic drug targeting. CRISPR based genome editing has been successfully used in vitro to mutate α-globin genes or enhancers of α-goblin to achieve clinically significant knockdowns of α-globin to the levels beneficial for patients with β-thalassaemia. This review summarises the current knowledge on the regulation of human α-globin genes and the clinical genetic data supporting the pathway of targeting α-globin as a treatment for β-thalassaemia. It also presents the progress of epigenetic drug and genome editing approaches currently in development to treat β-thalassaemia.
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Affiliation(s)
- Sachith Mettananda
- Department of Paediatrics, Faculty of Medicine, University of Kelaniya, Ragama, Sri Lanka
- University Paediatrics Unit, Colombo North Teaching Hospital, Ragama, Sri Lanka
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Hamid M, keikhaei B, Galehdari H, Saberi A, Sedaghat A, Shariati G, Mohammadi‐Anaei M. Alpha‐globin gene triplication and its effect in beta‐thalassemia carrier, sickle cell trait, and healthy individual. EJHAEM 2021; 2:366-374. [PMID: 35844714 PMCID: PMC9175967 DOI: 10.1002/jha2.262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Revised: 07/03/2021] [Accepted: 07/06/2021] [Indexed: 12/02/2022]
Abstract
The genotype and phenotype correlation between coinheritance of heterozygous beta‐thalassemia with the alpha‐globin triplication is unclear. In this study we have investigated and reviewed alpha triplication frequency in beta‐thalassemia carriers, sickle cell trait, and healthy individuals and its effect on hematological and phenotypical changes. In this study, 4005 beta‐thalassemia carriers, 455 sickle cell trait, and 2000 healthy individuals were included. Molecular characterization of beta and alpha‐thalassemia was performed. The frequencies of alpha‐globin triplication in beta‐thalassemia carriers, sickle cell trait, and healthy individuals were 67 (1.67%), 4 (0.88%), and 18 (0.9%), respectively. In total, the frequency of alpha‐triplications is approximately 89 (1.39%) in Khuzestan province, South of Iran population. We have compared the average hematological parameters of beta‐thalassemia carriers, sickle cell trait, and healthy individuals with and without alpha gene triplication. This mutation did not show any significant effect on the change of blood indices, neither in healthy individuals nor in sickle cell trait and beta‐thalassemia carriers. Therefore, there is no need to take more notice of anti 3.7 mutation in beta‐thalassemia carriers is opposed with some studies reported that the presence of excess alpha‐globin genes in beta‐thalassemia carriers can lead to the phenotype of beta‐thalassemia intermedia. Therefore, not every individual with triplicated alpha globin coinherited with beta‐thalassemia trait will have a significantly lower Hb than normal, and it is highly likely that none of them will need transfusion.
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Affiliation(s)
- Mohammad Hamid
- Department of Molecular Medicine, Biotechnology Research Center Pasteur Institute of Iran Tehran Iran
| | - Bijan keikhaei
- Research Center for Thalassemia and Hemoglobinopathy, Health Institute Ahvaz Jundishapur University of Medical Sciences Ahvaz Iran
| | - Hamid Galehdari
- Department of Genetics, Faculty of Sciences Shahid Chamran University of Ahvaz Ahvaz Iran
| | - Alihossein Saberi
- Department of Medical Genetics, Faculty of Medicine Ahvaz Jundishapur University of Medical Sciences Ahvaz Iran
| | - Alireza Sedaghat
- Department of Endocrinology Ahvaz Jundishapur University of Medical Sciences Ahvaz Iran
| | - Gholamreza Shariati
- Department of Medical Genetics, Faculty of Medicine Ahvaz Jundishapur University of Medical Sciences Ahvaz Iran
- Narges Medical Genetics and PND Laboratory Ahvaz Iran
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Patsali P, Papasavva P, Christou S, Sitarou M, Antoniou MN, Lederer CW, Kleanthous M. Relative and Absolute Quantification of Aberrant and Normal Splice Variants in HBBIVSI-110 (G > A) β-Thalassemia. Int J Mol Sci 2020; 21:E6671. [PMID: 32933098 PMCID: PMC7555009 DOI: 10.3390/ijms21186671] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Revised: 09/08/2020] [Accepted: 09/08/2020] [Indexed: 12/21/2022] Open
Abstract
The β-thalassemias are an increasing challenge to health systems worldwide, caused by absent or reduced β-globin (HBB) production. Of particular frequency in many Western countries is HBBIVSI-110(G > A) β-thalassemia (HGVS name: HBB:c.93-21G > A). Its underlying mutation creates an abnormal splice acceptor site in the HBB gene, and while partially retaining normal splicing of HBB, it severely reduces HBB protein expression from the mutant locus and HBB loci in trans. For the assessment of the underlying mechanisms and of therapies targeting β-thalassemia, accurate quantification of aberrant and normal HBB mRNA is essential, but to date, has only been performed by approximate methods. To address this shortcoming, we have developed an accurate, duplex reverse-transcription quantitative PCR assay for the assessment of the ratio and absolute quantities of normal and aberrant mRNA species as a tool for basic and translational research of HBBIVSI-110(G > A) β-thalassemia. The method was employed here to determine mRNA ratios and quantities in blood and primary cell culture samples and correlate them with HBB protein levels. Moreover, with its immediate utility for β-thalassemia and the mutation in hand, the approach can readily be adopted for analysis of alternative splicing or for quantitative assays of any disease-causing mutation that interferes with normal splicing.
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Affiliation(s)
- Petros Patsali
- Department of Molecular Genetics Thalassaemia, The Cyprus Institute of Neurology and Genetics, Nicosia 1683, Cyprus; (P.P.); (P.P.); (M.K.)
| | - Panayiota Papasavva
- Department of Molecular Genetics Thalassaemia, The Cyprus Institute of Neurology and Genetics, Nicosia 1683, Cyprus; (P.P.); (P.P.); (M.K.)
- Cyprus School of Molecular Medicine, Nicosia 1683, Cyprus
| | | | - Maria Sitarou
- Thalassaemia Clinic Larnaca, Ministry of Health, Larnaca 6301, Cyprus;
| | - Michael N. Antoniou
- Department of Medical and Molecular Genetics, King’s College London, London SE1 9RT, UK;
| | - Carsten W. Lederer
- Department of Molecular Genetics Thalassaemia, The Cyprus Institute of Neurology and Genetics, Nicosia 1683, Cyprus; (P.P.); (P.P.); (M.K.)
- Cyprus School of Molecular Medicine, Nicosia 1683, Cyprus
| | - Marina Kleanthous
- Department of Molecular Genetics Thalassaemia, The Cyprus Institute of Neurology and Genetics, Nicosia 1683, Cyprus; (P.P.); (P.P.); (M.K.)
- Cyprus School of Molecular Medicine, Nicosia 1683, Cyprus
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Weber L, Frati G, Felix T, Hardouin G, Casini A, Wollenschlaeger C, Meneghini V, Masson C, De Cian A, Chalumeau A, Mavilio F, Amendola M, Andre-Schmutz I, Cereseto A, El Nemer W, Concordet JP, Giovannangeli C, Cavazzana M, Miccio A. Editing a γ-globin repressor binding site restores fetal hemoglobin synthesis and corrects the sickle cell disease phenotype. SCIENCE ADVANCES 2020; 6:6/7/eaay9392. [PMID: 32917636 PMCID: PMC7015694 DOI: 10.1126/sciadv.aay9392] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 11/25/2019] [Indexed: 05/02/2023]
Abstract
Sickle cell disease (SCD) is caused by a single amino acid change in the adult hemoglobin (Hb) β chain that causes Hb polymerization and red blood cell (RBC) sickling. The co-inheritance of mutations causing fetal γ-globin production in adult life hereditary persistence of fetal Hb (HPFH) reduces the clinical severity of SCD. HPFH mutations in the HBG γ-globin promoters disrupt binding sites for the repressors BCL11A and LRF. We used CRISPR-Cas9 to mimic HPFH mutations in the HBG promoters by generating insertions and deletions, leading to disruption of known and putative repressor binding sites. Editing of the LRF-binding site in patient-derived hematopoietic stem/progenitor cells (HSPCs) resulted in γ-globin derepression and correction of the sickling phenotype. Xenotransplantation of HSPCs treated with gRNAs targeting the LRF-binding site showed a high editing efficiency in repopulating HSPCs. This study identifies the LRF-binding site as a potent target for genome-editing treatment of SCD.
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Affiliation(s)
- Leslie Weber
- Laboratory of Human Lymphohematopoiesis, INSERM UMR1163, Paris, France
- Paris Diderot University-Sorbonne Paris Cité, Paris, France
- Laboratory of chromatin and gene regulation during development, INSERM UMR1163, Paris, France
| | - Giacomo Frati
- Laboratory of chromatin and gene regulation during development, INSERM UMR1163, Paris, France
- Paris Descartes-Sorbonne Paris Cité University, Imagine Institute, Paris, France
| | - Tristan Felix
- Laboratory of chromatin and gene regulation during development, INSERM UMR1163, Paris, France
- Paris Descartes-Sorbonne Paris Cité University, Imagine Institute, Paris, France
| | - Giulia Hardouin
- Laboratory of chromatin and gene regulation during development, INSERM UMR1163, Paris, France
- Paris Descartes-Sorbonne Paris Cité University, Imagine Institute, Paris, France
| | | | - Clara Wollenschlaeger
- Laboratory of chromatin and gene regulation during development, INSERM UMR1163, Paris, France
- Paris Descartes-Sorbonne Paris Cité University, Imagine Institute, Paris, France
| | - Vasco Meneghini
- Laboratory of chromatin and gene regulation during development, INSERM UMR1163, Paris, France
- Paris Descartes-Sorbonne Paris Cité University, Imagine Institute, Paris, France
| | - Cecile Masson
- Paris-Descartes Bioinformatics Platform, Imagine Institute, Paris 75015, France
| | - Anne De Cian
- INSERM U1154, CNRS UMR7196, Museum National d'Histoire Naturelle, Paris, France
| | - Anne Chalumeau
- Laboratory of Human Lymphohematopoiesis, INSERM UMR1163, Paris, France
- Laboratory of chromatin and gene regulation during development, INSERM UMR1163, Paris, France
- Paris Descartes-Sorbonne Paris Cité University, Imagine Institute, Paris, France
| | - Fulvio Mavilio
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
- Audentes Therapeutics, San Francisco, CA, USA
| | | | - Isabelle Andre-Schmutz
- Laboratory of Human Lymphohematopoiesis, INSERM UMR1163, Paris, France
- Paris Descartes-Sorbonne Paris Cité University, Imagine Institute, Paris, France
| | | | - Wassim El Nemer
- Biologie Intégrée du Globule Rouge UMR_S1134, Inserm, Univ. Paris Diderot, Sorbonne Paris Cité, Univ. de la Réunion, Univ. des Antilles, Paris, France
- Institut National de la Transfusion Sanguine, F-75015 Paris, France
- Laboratoire d'Excellence GR-Ex, Paris, France
| | - Jean-Paul Concordet
- INSERM U1154, CNRS UMR7196, Museum National d'Histoire Naturelle, Paris, France
| | | | - Marina Cavazzana
- Laboratory of Human Lymphohematopoiesis, INSERM UMR1163, Paris, France
- Paris Descartes-Sorbonne Paris Cité University, Imagine Institute, Paris, France
- Biotherapy Department, Necker Children's Hospital, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Annarita Miccio
- Laboratory of chromatin and gene regulation during development, INSERM UMR1163, Paris, France.
- Paris Descartes-Sorbonne Paris Cité University, Imagine Institute, Paris, France
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Perera S, Allen A, Silva I, Hapugoda M, Wickramarathne MN, Wijesiriwardena I, Allen S, Rees D, Efremov DG, Fisher CA, Weatherall DJ, Premawardhena A. Genotype-phenotype association analysis identifies the role of α globin genes in modulating disease severity of β thalassaemia intermedia in Sri Lanka. Sci Rep 2019; 9:10116. [PMID: 31300739 PMCID: PMC6625979 DOI: 10.1038/s41598-019-46674-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 06/28/2019] [Indexed: 01/14/2023] Open
Abstract
β thalassaemia intermedia (βTI) are a heterogeneous group of disorders known to be extremely phenotypically diverse. This group is more complex to manage as no definitive treatment guidelines exist unlike for β thalassaemia major (βTM). There are only a few studies looking at genotype phenotype associations of βTI outside the Mediterranean region. The reasons for the diverse clinical phenotype in βTI are unknown. We categorized fifty Sri Lankan patients diagnosed with βTI as mild, moderate or severe according to published criteria. DNA samples were genotyped for β thalassaemia mutations, α globin genotype and copy number and known genetic modifiers of haemoglobin F production. There were 26/50 (52.0%) in mild group and 12/50 (24.0%) each in moderate and sever categories. 18/26 (69.2%) classified as mild were β heterozygotes and 17/18 (94.4%) had excess α globin genes. 11/12 (91.6%) classified as moderate were β heterozygotes and 8/11 (72.2%) had excess α globin genes. In contrast, 8/12 (66.7%) classified as severe were β homozygotes and 7/8(87.5%) had α globin gene deletions. In Sri Lanka, co-inheritance of either excess α globin genes in β thalassaemia heterozygotes or α globin gene deletions in β thalassaemia homozygotes is a significant factor in modulating disease severity.
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Affiliation(s)
- Shiromi Perera
- Faculty of Medicine, University of Kelaniya, Kelaniya, Sri Lanka.
| | - Angela Allen
- MRC Molecular Hematology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK.,Centre for Tropical and Infectious Disease, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Ishari Silva
- Hemal's Thalassemia Care Unit, North Colombo Teaching Hospital, Ragama, Sri Lanka
| | - Menaka Hapugoda
- Faculty of Medicine, University of Kelaniya, Kelaniya, Sri Lanka
| | | | | | - Stephen Allen
- Centre for Tropical and Infectious Disease, Liverpool School of Tropical Medicine, Liverpool, UK
| | - David Rees
- Department of Paediatric Haematology, King's College Hospital, London, UK
| | - Dimitar G Efremov
- Molecular Hematology Unit, International Centre for Genetic Engineering and Biotechnology, Rome, Italy
| | - Christopher A Fisher
- MRC Molecular Hematology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - David J Weatherall
- MRC Molecular Hematology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Anuja Premawardhena
- Faculty of Medicine, University of Kelaniya, Kelaniya, Sri Lanka.,Hemal's Thalassemia Care Unit, North Colombo Teaching Hospital, Ragama, Sri Lanka
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Traivaree C, Monsereenusorn C, Rujkijyanont P, Prasertsin W, Boonyawat B. Genotype-phenotype correlation among beta-thalassemia and beta-thalassemia/HbE disease in Thai children: predictable clinical spectrum using genotypic analysis. J Blood Med 2018; 9:35-41. [PMID: 29695942 PMCID: PMC5905821 DOI: 10.2147/jbm.s159295] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Introduction Beta-thalassemia is a group of inherited hemolytic anemias and one of the most common genetic disorders in Thailand. The clinical spectrum of beta-thalassemia disease ranges from mild to severe clinical symptoms including mild beta-thalassemia intermedia (TI) and severe beta-thalassemia major (TM). Objective This study aimed to determine the correlation between beta-globin gene (HBB) mutations and their phenotypic manifestations by evaluating patients' clinical characteristics, transfusion requirements, growth and hematologic parameters, and hemoglobin typing among pediatric patients treated at Phramongkutklao Hospital. Materials and methods Seventy beta-thalassemia patients, including 63 with beta-thalassemia/hemoglobin E (HbE) and 7 with either homozygous or compound heterozygous beta-thalassemia, were enrolled in this study. Their clinical presentation, growth parameters and laboratory findings were reviewed and analyzed. The mean follow-up time was 10.52±5.62 years. Mutation analysis in each individual was performed using multiplex amplification refractory mutation system (M-ARMS), direct DNA sequencing of beta-globin gene and gap PCR for 3.4 kb deletion detection. Results All 7 homozygous and compound heterozygous beta-thalassemia patients were classified in TM. Among 63 patients with beta-thalassemia/HbE, 58 were classified in TM and 4 were classified in TI. Mean age at diagnosis was 0.8±0.49 years for homozygous or compound heterozygous beta-thalassemia and 3.43±3.5 years for beta-thalassemia/HbE. The most common HBB mutation was HBB:c.126_129delCTTT [codon 41/42 (-TCTT)] found in 34 alleles (48.6%). The height for age was also lower in homozygous beta-thalassemia patients (<3rd percentile) compared to compound heterozygous beta-thalassemia patients (25-50th percentile). Conclusion This study revealed a genotype-phenotype correlation of the most prevalent beta-thalassemia in Thai children using diagnostic capacity in genotypic analysis of HBB mutation. Our findings can provide a better prediction of clinical manifestation and severity by early identification of the type of the HBB mutations.
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Affiliation(s)
- Chanchai Traivaree
- Division of Hematology/Oncology, Department of Pediatrics, Phramongkutklao Hospital and College of Medicine, Bangkok, Thailand
| | - Chalinee Monsereenusorn
- Division of Hematology/Oncology, Department of Pediatrics, Phramongkutklao Hospital and College of Medicine, Bangkok, Thailand
| | - Piya Rujkijyanont
- Division of Hematology/Oncology, Department of Pediatrics, Phramongkutklao Hospital and College of Medicine, Bangkok, Thailand
| | - Warakorn Prasertsin
- Department of Pediatrics, Queen Savang Vadhana Memorial Hospital, Chonburi, Thailand
| | - Boonchai Boonyawat
- Division of Genetics, Department of Pediatrics, Phramongkutklao Hospital and College of Medicine, Bangkok, Thailand
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Evaluation of the Clinical and Laboratory Characteristics of Previously Followed-up Thalassemia Intermedia Patients to Provide Them Better Care in the Future. J Pediatr Hematol Oncol 2017; 39:440-444. [PMID: 28719510 DOI: 10.1097/mph.0000000000000914] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The increased awareness about the severity of complications in thalassemia intermedia patients led authorities to develop strategies for better management and follow-up of these patients. In this study, we aimed to define the clinical and laboratory characteristics in previously followed-up β-thalassemia intermedia patients and wanted to gain an insight about the follow-up of this patient population in a developing country to provide them better care in the future. The mean age at diagnosis was 4 years, and the mean hemoglobin was 7.13 g/dL. The mean age at the beginning of regular transfusion was 4.8 years. An overall 74% of patients were on a regular transfusion program. The mean ferritin values at diagnosis and the last follow-up were 487 and 1225 ng/mL, respectively. The most common mutations detected in patients were IVS-I-110, IVS-I-6, IVS-II-1, and FCS 8/9 in order of frequency. Complications were seen in 48% of patients. The most common complications were osteopenia/osteoporosis (34%), growth retardation (24%), hypogonadism (18%), and cardiomyopathy (13%). In conclusion, the relatively higher complication rate in our patients who were previously treated highlights once again the need for an increased effort for optimal management and follow-up of this specific group of patients.
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Molecular basis of β thalassemia and potential therapeutic targets. Blood Cells Mol Dis 2017; 70:54-65. [PMID: 28651846 DOI: 10.1016/j.bcmd.2017.06.001] [Citation(s) in RCA: 102] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 06/09/2017] [Accepted: 06/09/2017] [Indexed: 12/15/2022]
Abstract
The remarkable phenotypic diversity of β thalassemia that range from severe anemia and transfusion-dependency, to a clinically asymptomatic state exemplifies how a spectrum of disease severity can be generated in single gene disorders. While the genetic basis for β thalassemia, and how severity of the anemia could be modified at different levels of its pathophysiology have been well documented, therapy remains largely supportive with bone marrow transplant being the only cure. Identification of the genetic variants modifying fetal hemoglobin (HbF) production in combination with α globin genotype provide some prediction of disease severity for β thalassemia but generation of a personalized genetic risk score to inform prognosis and guide management requires a larger panel of genetic modifiers yet to be discovered. Nonetheless, genetic studies have been successful in characterizing the key variants and pathways involved in HbF regulation, providing new therapeutic targets for HbF reactivation. BCL11A has been established as a quantitative repressor, and progress has been made in manipulating its expression using genomic and gene-editing approaches for therapeutic benefits. Recent discoveries and understanding in the mechanisms associated with ineffective and abnormal erythropoiesis have also provided additional therapeutic targets, a couple of which are currently being tested in clinical trials.
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Lai Y, Chen Y, Chen B, Zheng H, Yi S, Li G, Wei H, He S, Zheng C. Genetic Variants at BCL11A and HBS1L-MYB loci Influence Hb F Levels in Chinese Zhuang β-Thalassemia Intermedia Patients. Hemoglobin 2017; 40:405-410. [PMID: 28361591 DOI: 10.1080/03630269.2016.1253586] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Increased Hb F levels can ameliorate the symptoms of β-thalassemia (β-thal). Due to the genetic heterogenicity of β-thal, the relationship between genetic variants in modifier genes and Hb F level has been studied in different populations. The Chinese Zhuang has the second largest population in China and has 6.78% prevalence of β-thal. However, the effects of these single nucleotide polymorphism (SNP) variants on the Hb F levels of β-thal intermedia (β-TI) patients in this population have not been reported. To explore the association between modifier loci (β-globin gene cluster, HBS1L-MYB intergenic region and BCL11A) and Hb F levels in Chinese Zhuang β-TI patients, 96 unrelated β-TI patients (50 males and 46 females) with different Hb F levels were recruited and genotyped by mass spectrometry. A total of 13 SNPs were confirmed to be in a significant relationship with Hb F levels in this population. Of these, high-risk genotypes of six Hb F-associated SNPs, rs9376090, rs7776054, rs9399137, rs9389268, rs9402685 in the HBS1L-MYB intergenic region and rs189984760 in the BCL11A locus, showed association with high Hb F levels, especially for SNPs in linkage disequilibrium. One novel Hb F-associated SNP, rs189984760, was identified in our study. Our findings will be of valuable reference for correlation between modifier genes and Hb F in Chinese Zhuang populations and may lead to better understand the modifying mechanisms for β-thal.
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Affiliation(s)
- Yunli Lai
- a Genetic and Metabolic Central Laboratory , Guangxi Zhuang Autonomous Region Women and Children Care Hospital , Nanning , Guangxi Province , People's Republic of China
| | - Yun Chen
- a Genetic and Metabolic Central Laboratory , Guangxi Zhuang Autonomous Region Women and Children Care Hospital , Nanning , Guangxi Province , People's Republic of China
| | - Biyan Chen
- a Genetic and Metabolic Central Laboratory , Guangxi Zhuang Autonomous Region Women and Children Care Hospital , Nanning , Guangxi Province , People's Republic of China
| | - Haiyang Zheng
- a Genetic and Metabolic Central Laboratory , Guangxi Zhuang Autonomous Region Women and Children Care Hospital , Nanning , Guangxi Province , People's Republic of China
| | - Sheng Yi
- a Genetic and Metabolic Central Laboratory , Guangxi Zhuang Autonomous Region Women and Children Care Hospital , Nanning , Guangxi Province , People's Republic of China
| | - Guojian Li
- b Guangxi Health and Family Planning Commission , Nanning , Guangxi Province , People's Republic of China
| | - Hongwei Wei
- a Genetic and Metabolic Central Laboratory , Guangxi Zhuang Autonomous Region Women and Children Care Hospital , Nanning , Guangxi Province , People's Republic of China
| | - Sheng He
- a Genetic and Metabolic Central Laboratory , Guangxi Zhuang Autonomous Region Women and Children Care Hospital , Nanning , Guangxi Province , People's Republic of China
| | - Chenguang Zheng
- a Genetic and Metabolic Central Laboratory , Guangxi Zhuang Autonomous Region Women and Children Care Hospital , Nanning , Guangxi Province , People's Republic of China
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12
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Lai Y, Zhou L, Yi S, Chen Y, Tang Y, Yi S, Yang Z, Wei H, Zheng C, He S. The association between four SNPs (rs7482144, rs4671393, rs28384513 and rs4895441) and fetal hemoglobin levels in Chinese Zhuang β-thalassemia intermedia patients. Blood Cells Mol Dis 2017; 63:52-57. [DOI: 10.1016/j.bcmd.2017.01.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2016] [Revised: 01/17/2017] [Accepted: 01/20/2017] [Indexed: 11/25/2022]
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13
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Traeger-Synodinos J, Harteveld CL. Preconception carrier screening and prenatal diagnosis in thalassemia and hemoglobinopathies: challenges and future perspectives. Expert Rev Mol Diagn 2017; 17:281-291. [DOI: 10.1080/14737159.2017.1285701] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Joanne Traeger-Synodinos
- Department of Medical Genetics, National and Kapodistrian University of Athens, St. Sophia’s Children’s Hospital, Athens, Greece
| | - Cornelis L. Harteveld
- Department of Clinical Genetics, Laboratory for Diagnostic Genome Analysis (LDGA), Leiden, The Netherlands
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14
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Thein SL. Genetic Basis and Genetic Modifiers of β-Thalassemia and Sickle Cell Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1013:27-57. [PMID: 29127676 DOI: 10.1007/978-1-4939-7299-9_2] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
β-thalassemia and sickle cell disease (SCD) are prototypical Mendelian single gene disorders, both caused by mutations affecting the adult β-globin gene. Despite the apparent genetic simplicity, both disorders display a remarkable spectrum of phenotypic severity and share two major genetic modifiers-α-globin genotype and innate ability to produce fetal hemoglobin (HbF, α2γ2).This article provides an overview of the genetic basis for SCD and β-thalassemia, and genetic modifiers identified through phenotype correlation studies. Identification of the genetic variants modifying HbF production in combination with α-globin genotype provide some prediction of disease severity for β-thalassemia and SCD but generation of a personalized genetic risk score to inform prognosis and guide management requires a larger panel of genetic modifiers yet to be discovered.Nonetheless, genetic studies have been successful in characterizing some of the key variants and pathways involved in HbF regulation, providing new therapeutic targets for HbF reactivation.
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Affiliation(s)
- Swee Lay Thein
- Sickle Cell Branch, National Heart, Lung and Blood Institute, National Institutes of Health, Building 10, Room 6S241 MSC 1589, 10 Center Dr., Bethesda, MD, 20892-1589, USA.
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15
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Trehan U, Garewal G, Kaul D, Das R. Molecular Pathology of Thalassemia and Triplicated Locus in North Indian Population; Interaction with Heterozygous Thalassemia. Hematology 2016; 6:153-60. [DOI: 10.1080/10245332.2001.11746566] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Affiliation(s)
- Urvashi Trehan
- department of Hematology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Gurjeewan Garewal
- department of Hematology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Deepak Kaul
- Department of Experimental Medicine and Biotechnology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Reena Das
- department of Hematology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
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16
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Mettananda S, Gibbons RJ, Higgs DR. Understanding α-globin gene regulation and implications for the treatment of β-thalassemia. Ann N Y Acad Sci 2015; 1368:16-24. [PMID: 26695885 DOI: 10.1111/nyas.12988] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Over the past three decades, a vast amount of new information has been uncovered describing how the globin genes are regulated. This knowledge has provided significant insights into the general understanding of the regulation of human genes. It is now known that molecular defects within and around the α- and β-globin genes, as well as in the distant regulatory elements, can cause thalassemia. Unbalanced production of globin chains owing to defective synthesis of one, and the continued unopposed synthesis of another, is the central causative factor in the cellular pathology and pathophysiology of thalassemia. A large body of clinical, genetic, and experimental evidence suggests that altering globin chain imbalance by reducing the production of α-globin synthesis ameliorates the disease severity in patients with β-thalassemia. With the development of new genetic-based therapeutic tools that have a potential to decrease the expression of a selected gene in a tissue-specific manner, the possibility of decreasing expression of the α-globin gene to improve the clinical severity of β-thalassemia could become a reality.
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Affiliation(s)
- Sachith Mettananda
- Medical Research Council (MRC) Molecular Hematology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom.,Department of Pediatrics, Faculty of Medicine, University of Kelaniya, Sri Lanka
| | - Richard J Gibbons
- Medical Research Council (MRC) Molecular Hematology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom
| | - Douglas R Higgs
- Medical Research Council (MRC) Molecular Hematology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom.,Oxford National Institute for Health Research Biomedical Research Centre, Blood Theme, Oxford University Hospital, Oxford, United Kingdom
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17
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α-Globin as a molecular target in the treatment of β-thalassemia. Blood 2015; 125:3694-701. [PMID: 25869286 DOI: 10.1182/blood-2015-03-633594] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Accepted: 03/31/2015] [Indexed: 12/31/2022] Open
Abstract
The thalassemias, together with sickle cell anemia and its variants, are the world's most common form of inherited anemia, and in economically undeveloped countries, they still account for tens of thousands of premature deaths every year. In developed countries, treatment of thalassemia is also still far from ideal, requiring lifelong transfusion or allogeneic bone marrow transplantation. Clinical and molecular genetic studies over the course of the last 50 years have demonstrated how coinheritance of modifier genes, which alter the balance of α-like and β-like globin gene expression, may transform severe, transfusion-dependent thalassemia into relatively mild forms of anemia. Most attention has been paid to pathways that increase γ-globin expression, and hence the production of fetal hemoglobin. Here we review the evidence that reduction of α-globin expression may provide an equally plausible approach to ameliorating clinically severe forms of β-thalassemia, and in particular, the very common subgroup of patients with hemoglobin E β-thalassemia that makes up approximately half of all patients born each year with severe β-thalassemia.
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18
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Boonyawat B, Monsereenusorn C, Traivaree C. Molecular analysis of beta-globin gene mutations among Thai beta-thalassemia children: results from a single center study. APPLICATION OF CLINICAL GENETICS 2014; 7:253-8. [PMID: 25525381 PMCID: PMC4266330 DOI: 10.2147/tacg.s73058] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Background Beta-thalassemia is one of the most common genetic disorders in Thailand. Clinical phenotype ranges from silent carrier to clinically manifested conditions including severe beta-thalassemia major and mild beta-thalassemia intermedia. Objective This study aimed to characterize the spectrum of beta-globin gene mutations in pediatric patients who were followed-up in Phramongkutklao Hospital. Patients and methods Eighty unrelated beta-thalassemia patients were enrolled in this study including 57 with beta-thalassemia/hemoglobin E, eight with homozygous beta-thalassemia, and 15 with heterozygous beta-thalassemia. Mutation analysis was performed by multiplex amplification refractory mutation system (M-ARMS), direct DNA sequencing of beta-globin gene, and gap polymerase chain reaction for 3.4 kb deletion detection, respectively. Results A total of 13 different beta-thalassemia mutations were identified among 88 alleles. The most common mutation was codon 41/42 (-TCTT) (37.5%), followed by codon 17 (A>T) (26.1%), IVS-I-5 (G>C) (8%), IVS-II-654 (C>T) (6.8%), IVS-I-1 (G>T) (4.5%), and codon 71/72 (+A) (2.3%), and all these six common mutations (85.2%) were detected by M-ARMS. Six uncommon mutations (10.2%) were identified by DNA sequencing including 4.5% for codon 35 (C>A) and 1.1% initiation codon mutation (ATG>AGG), codon 15 (G>A), codon 19 (A>G), codon 27/28 (+C), and codon 123/124/125 (-ACCCCACC), respectively. The 3.4 kb deletion was detected at 4.5%. The most common genotype of beta-thalassemia major patients was codon 41/42 (-TCTT)/codon 26 (G>A) or betaE accounting for 40%. Conclusion All of the beta-thalassemia alleles have been characterized by a combination of techniques including M-ARMS, DNA sequencing, and gap polymerase chain reaction for 3.4 kb deletion detection. Thirteen mutations account for 100% of the beta-thalassemia genes among the pediatric patients in our study.
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Affiliation(s)
- Boonchai Boonyawat
- Division of Genetics, Department of Pediatrics, Phramongkutklao Hospital and College of Medicine, Bangkok, Thailand
| | - Chalinee Monsereenusorn
- Division of Hematology/Oncology, Department of Pediatrics, Phramongkutklao Hospital and College of Medicine, Bangkok, Thailand
| | - Chanchai Traivaree
- Division of Hematology/Oncology, Department of Pediatrics, Phramongkutklao Hospital and College of Medicine, Bangkok, Thailand
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19
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Menzel S, Rooks H, Zelenika D, Mtatiro SN, Gnanakulasekaran A, Drasar E, Cox S, Liu L, Masood M, Silver N, Garner C, Vasavda N, Howard J, Makani J, Adekile A, Pace B, Spector T, Farrall M, Lathrop M, Thein SL. Global genetic architecture of an erythroid quantitative trait locus, HMIP-2. Ann Hum Genet 2014; 78:434-51. [PMID: 25069958 PMCID: PMC4303951 DOI: 10.1111/ahg.12077] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Accepted: 05/20/2014] [Indexed: 12/16/2022]
Abstract
HMIP-2 is a human quantitative trait locus affecting peripheral numbers, size and hemoglobin composition of red blood cells, with a marked effect on the persistence of the fetal form of hemoglobin, HbF, in adults. The locus consists of multiple common variants in an enhancer region for MYB (chr 6q23.3), which encodes the hematopoietic transcription factor cMYB. Studying a European population cohort and four African-descended groups of patients with sickle cell anemia, we found that all share a set of two spatially separate HbF-promoting alleles at HMIP-2, termed “A” and “B.” These typically occurred together (“A–B”) on European chromosomes, but existed on separate homologous chromosomes in Africans. Using haplotype signatures for “A” and “B,” we interrogated public population datasets. Haplotypes carrying only “A” or “B” were typical for populations in Sub-Saharan Africa. The “A–B” combination was frequent in European, Asian, and Amerindian populations. Both alleles were infrequent in tropical regions, possibly undergoing negative selection by geographical factors, as has been reported for malaria with other hematological traits. We propose that the ascertainment of worldwide distribution patterns for common, HbF-promoting alleles can aid their further genetic characterization, including the investigation of gene–environment interaction during human migration and adaptation.
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Affiliation(s)
| | | | | | - Siana N Mtatiro
- King's College London, London, UK.,Muhimbili University, Dar es Salaam, Tanzania
| | | | - Emma Drasar
- King's College London, London, UK.,King's College Hospital NHS Foundation Trust, London, UK
| | - Sharon Cox
- Muhimbili University, Dar es Salaam, Tanzania
| | - Li Liu
- University of Texas at Dallas, Richardson, TX, USA
| | | | | | - Chad Garner
- University of California Irvine School of Medicine, Irvine, CA, USA
| | | | - Jo Howard
- King's College London, London, UK.,Guy's and St Thomas' Hospital NHS Foundation Trust, London, UK
| | | | | | - Betty Pace
- Georgia Regents University, Augusta, GA, USA
| | | | - Martin Farrall
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | | | - Swee Lay Thein
- King's College London, London, UK.,King's College Hospital NHS Foundation Trust, London, UK
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20
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β -thalassemia intermedia in Northern Iraq: a single center experience. BIOMED RESEARCH INTERNATIONAL 2014; 2014:262853. [PMID: 24719849 PMCID: PMC3955643 DOI: 10.1155/2014/262853] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 11/17/2013] [Revised: 01/18/2014] [Accepted: 01/20/2014] [Indexed: 12/20/2022]
Abstract
To investigate the molecular basis of β-thalassemia intermedia in Northern Iraq and evaluate its management practices, a total of 74 patients from 51 families were enrolled. The patients were clinically and hematologically reevaluated, and had their β-thalassemia mutations characterized, as well as the number of α-globin genes and Xmn I Gγ −158 (C>T) polymorphism studied. Out of 14 β-thalassemia mutations identified, the four most common were IVS-I-6 (T>C) [33.3%], IVS-II-I (G>A) [21.1%], codon 82/83(−G) [10.1%], and codon 8 (−AA) [8.1%]. The most common contributing factors to the less severe phenotype of thalassemia intermedia were found to be the inheritance of mild β-thalassemia alleles and the Xmn I polymorphism, while concomitant α-thalassemia had a limited role. Several complications were documented including: pulmonary hypertension in 20.4%, diabetes mellitus in 1.4%, hypothyroidism in 2.9%, and heart failure in 2.7%, while no documented cases of venous thrombosis were found. Compared to their counterparts in several Mediterranean countries, it appears that our patients were much less frequently transfused and had a lower proportion of patients who were splenectomized, on iron chelation, or hydroxycarbamide therapy. Such practices require further scrutiny to ensure that a better level of care is provided and that growth retardation, skeletal changes, and other complications are prevented or reduced.
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21
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Thachil J, Owusu-Ofori S, Bates I. Haematological Diseases in the Tropics. MANSON'S TROPICAL INFECTIOUS DISEASES 2014. [PMCID: PMC7167525 DOI: 10.1016/b978-0-7020-5101-2.00066-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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22
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Molecular basis of transfusion dependent beta-thalassemia major patients in Sabah. J Hum Genet 2013; 59:119-23. [PMID: 24369358 DOI: 10.1038/jhg.2013.131] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Revised: 11/28/2013] [Accepted: 11/29/2013] [Indexed: 11/08/2022]
Abstract
Beta-thalassemia is one of the most prevalent inherited diseases and a public health problem in Malaysia. Malaysia is geographically divided into West and East Malaysia. In Sabah, a state in East Malaysia, there are over 1000 estimated cases of β-thalassemia major patients. Accurate population frequency data of the molecular basis of β-thalassemia major are needed for planning its control in the high-risk population of Sabah. Characterization of β-globin gene defects was done in 252 transfusion dependent β-thalassemia patients incorporating few PCR techniques. The study demonstrates that β-thalassemia mutations inherited are ethnically dependent. It is important to note that 86.9% of transfusion-dependent β-thalassemia major patients in Sabah were of the indigenous population and homozygous for a single mutation. The Filipino β(0)-deletion was a unique mutation found in the indigenous population of Sabah. Mutations common in West Malaysia were found in 11 (4.3%) patients. Four rare mutations (Hb Monroe, CD 8/9, CD 123/124/125 and IVS I-2) were also found. This study is informative on the population genetics of β-thalassemia major in Sabah.
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23
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Jouini L, Sahli CA, Laaouini N, Ouali F, Youssef IB, Dakhlaoui B, Othmeni R, Ouennich F, Fredj SH, Siala H, Becher M, Toumi NE, Fattoum S, Hafsia R, Bibi A, Messaoud T. Association between clinical expression and molecular heterogeneity in β-thalassemia Tunisian patients. Mol Biol Rep 2013; 40:6205-12. [DOI: 10.1007/s11033-013-2732-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2012] [Accepted: 09/14/2013] [Indexed: 10/26/2022]
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24
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Disruption of the Hbs1l-Myb locus causes hereditary persistence of fetal hemoglobin in a mouse model. Mol Cell Biol 2013; 33:1687-95. [PMID: 23428869 DOI: 10.1128/mcb.01617-12] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The human β-globin locus is comprised of embryonic, fetal, and adult globin genes, each of which is expressed at distinct stages of pre- and postnatal development. Functional defects in globin proteins or expression results in mild to severe anemia, such as in sickle-cell disease or β-thalassemia, but the clinical symptoms of both disorders are ameliorated by persistent expression of the fetal globin genes. Recent genome-wide association studies (GWAS) identified the intergenic region between the HBS1L and MYB loci as a candidate modifier of fetal hemoglobin expression in adults. However, it remains to be clarified whether the enhancer activity within the HBS1L-MYB regulatory domain contributes to the production of fetal hemoglobin in adults. Here we report a new mouse model of hereditary persistence of fetal hemoglobin (HPFH) in which a transgene was randomly inserted into the orthologous murine Hbs1l-Myb locus. This mutant mouse exhibited typically elevated expression of embryonic globins and hematopoietic parameters similar to those observed in human HPFH. These results support the contention that mutation of the HBS1L-MYB genomic domain is responsible for elevated expression of the fetal globin genes, and this model serves as an important means for the analysis of networks that regulate fetal globin gene expression.
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Ho PJ, Tay L, Lindeman R, Catley L, Bowden DK. Australian guidelines for the assessment of iron overload and iron chelation in transfusion-dependent thalassaemia major, sickle cell disease and other congenital anaemias. Intern Med J 2012; 41:516-24. [PMID: 21615659 DOI: 10.1111/j.1445-5994.2011.02527.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Iron overload is the most important cause of mortality in patients with thalassaemia major. Iron chelation is therefore a critical issue in the management of these patients and others with transfusion-dependent haemoglobinopathies and congenital anaemias. In recent years, significant developments have been made in the assessment of iron overload, including the use of magnetic resonance imaging for measuring liver and cardiac iron. Advances in the modalities available for iron chelation, with the advent of oral iron chelators including deferiprone and deferasirox in addition to parenteral desferrioxamine, have expanded treatment options. A group of Australian haematologists has convened to formulate guidelines for managing iron overload on the basis of available evidence, and to describe best consensus practice as undertaken in major Australian Haemoglobinopathy units. The results of their discussions are described in this article, with the aim of providing guidance in the management of iron overload in these patients.
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Affiliation(s)
- P J Ho
- Institute of Haematology, Royal Prince Alfred Hospital, Sydney, New South Wales, Australia.
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26
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Sivalingam M, Looi ML, Zakaria SZS, Hamidah NH, Alias H, Latiff ZA, Ibrahim H, Jamal R. Molecular study and genotype/phenotype correlation of β Thalassemia in Malaysia. Int J Lab Hematol 2012; 34:377-82. [PMID: 22335963 DOI: 10.1111/j.1751-553x.2012.01405.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
INTRODUCTION To study the ß-gene mutations spectrum, the genotype/phenotype correlation, the modulatory effect of co-inherited factors such as α-gene mutations and of Xmn1 polymorphism in a large cohort of Malaysian patients. METHODS A total of 264 cases clinically diagnosed as Thalassemia major (TM) (111), Thalassemia intermedia (21), HbE-β Thalassemia (131), and 1 HbE homozygous were studied. The detection of α and ß gene mutations and characterization of Xmn1 polymorphism were performed by multiplex PCR, amplification refractory mutation system (ARMS), DNA sequencing, and restriction fragment length polymorphism (RFLP)-PCR. RESULTS A total of 19 ß Thalassemia mutations were characterized. CD26 and CD41/42 were the most common found in the Malay and Chinese population, respectively. The sensitivity of the clinical diagnosis for β TM, thalassemia intermedia, and HbE/β thalassemia was 94.0%, 15.2%, and 89.2%, respectively. Patients with Xmn1 heterozygosity [+/-] required less frequent transfusion compared with those without the polymorphism. Co-inheritance of α-thalassemia alleviates the severity of HbE-β thalassemia in our cohort. CONCLUSION Molecular analysis should be used for a better diagnosis and management of β thalassemia.
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Affiliation(s)
- M Sivalingam
- UKM Medical Molecular Biology Institute (UMBI), Kuala Lumpur, Cheras, Malaysia
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27
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Oberoi S, Das R, Panigrahi I, Kaur J, Marwaha RK. Xmn1-G γ polymorphism and clinical predictors of severity of disease in β-thalassemia intermedia. Pediatr Blood Cancer 2011; 57:1025-8. [PMID: 21755589 DOI: 10.1002/pbc.23175] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2010] [Accepted: 03/30/2011] [Indexed: 11/10/2022]
Abstract
BACKGROUND To determine the prevalence of Xmn1-(G)γ polymorphism in North Indian children and adolescents with β thalassemia intermedia (TI) and to correlate it with disease severity. METHODS All patients of thalassemia intermedia presenting to the pediatric hematology clinic of a tertiary care hospital in North India were enrolled. Clinical severity of their disease was assessed by a phenotypic score proposed by Phadke and Agarwal. They were classified according to status of their Xmn1-(G)γ polymorphism as Xmn1-(G)γ +/+, Xmn1-(G)γ +/-, and Xmn1-(G)γ -/- by molecular analysis. RESULTS A total of 104 patients were enrolled. Severe TI was seen in 56.7% (59) patients, while 43.3% (45) had non-severe TI. Jaundice was more frequent in severe TI than in non-severe TI. Xmn1-(G)γ +/+ was present in 25.9% (25) patients. The frequency of the Xmn1-(G)γ +/- and Xmn1-(G)γ -/- was 22% and 37.3% in severe TI children. The corresponding frequencies were 31.1% and 42.2% in non-severe TI group respectively. No significant correlation was observed between the Xmn1-(G)γ polymorphism and severity of thalassemia, age at onset of symptoms, age at diagnosis, age at first transfusion, transfusion frequency or average hemoglobin levels. HbF level was significantly higher in Xmn1-(G)γ +/+ and Xmn1-(G)γ +/- patients. CONCLUSIONS This study showed that although the prevalence of Xmn1-(G)γ polymorphism is high in β thalassemia intermedia patients, it alone could not predict clinical severity in TI patients. Further refinement and validation of clinical scoring system is necessary for guiding appropriate management.
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Affiliation(s)
- Sapna Oberoi
- Department of Pediatrics, Pediatric Hematology-Oncology Unit, Advanced Pediatric Centre, Postgraduate Institute of Medical Education and Research, Chandigarh, UT, India
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28
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Xie SY, Li W, Ren ZR, Huang SZ, Zeng F, Zeng YT. Correction of β654-thalassaemia mice using direct intravenous injection of siRNA and antisense RNA vectors. Int J Hematol 2011; 93:301-310. [PMID: 21369857 DOI: 10.1007/s12185-010-0727-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2010] [Revised: 10/27/2010] [Accepted: 11/10/2010] [Indexed: 01/17/2023]
Abstract
Although the therapeutic efficacy of β(654)-thalassaemia treatment using a combination of RNAi and antisense RNA to balance the synthesis of α- and β-globin chains has been demonstrated previously, and the safety of lentiviral delivery remains unclear. Herein, we used the same β(654)-thalassaemia mouse model to develop a therapy involving direct delivery of siRNA and antisense RNA plasmids via intravenous injection to simultaneously knock down α-globin transcript levels and restore correct β-globin splicing. The amount of α-globin mRNAs in siRNA-treated MEL cells decreased significantly, and the properly spliced β-globin mRNA was restored in HeLaβ(654) cells transfected with pcDNA-antisense plasmid. Furthermore, treatment of β(654)-thalassaemic mice with siRNA and antisense RNA plasmids resulted in significant reduction of poikilocytosis and reticulocyte counts in blood samples, decreased nucleated cell populations in bone marrow, and reduced intrasinusoidal extramedullary haematopoiesis loci and iron accumulation in liver. RT-PCR analysis revealed that treatment resulted in down-regulation of α-globin mRNA synthesis by ~50% along with an increase in the presence of normally spliced β-globin transcripts, indicating that the phenotypic changes observed in β(654)-thalassaemic mice following treatment resulted from restoration of the balance of α/β-globin biosynthesis.
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Affiliation(s)
- Shu-Yang Xie
- Shanghai Institute of Medical Genetics, Shanghai Children's Hospital, Shanghai Jiao Tong University School of Medicine, 24/1400 West Beijing Road, Shanghai, 200040, People's Republic of China
| | - Wei Li
- Shanghai Institute of Medical Genetics, Shanghai Children's Hospital, Shanghai Jiao Tong University School of Medicine, 24/1400 West Beijing Road, Shanghai, 200040, People's Republic of China
| | - Zhao-Rui Ren
- Shanghai Institute of Medical Genetics, Shanghai Children's Hospital, Shanghai Jiao Tong University School of Medicine, 24/1400 West Beijing Road, Shanghai, 200040, People's Republic of China
- Key Lab of Medical Embryo Molecular Biology, Ministry of Health, China, Shanghai Lab of Embryo and Reproduction Engineering, Shanghai, People's Republic of China
| | - Shu-Zhen Huang
- Shanghai Institute of Medical Genetics, Shanghai Children's Hospital, Shanghai Jiao Tong University School of Medicine, 24/1400 West Beijing Road, Shanghai, 200040, People's Republic of China
- Key Lab of Medical Embryo Molecular Biology, Ministry of Health, China, Shanghai Lab of Embryo and Reproduction Engineering, Shanghai, People's Republic of China
| | - Fanyi Zeng
- Shanghai Institute of Medical Genetics, Shanghai Children's Hospital, Shanghai Jiao Tong University School of Medicine, 24/1400 West Beijing Road, Shanghai, 200040, People's Republic of China.
- Key Lab of Medical Embryo Molecular Biology, Ministry of Health, China, Shanghai Lab of Embryo and Reproduction Engineering, Shanghai, People's Republic of China.
- Institute of Medical Science, Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China.
| | - Yi-Tao Zeng
- Shanghai Institute of Medical Genetics, Shanghai Children's Hospital, Shanghai Jiao Tong University School of Medicine, 24/1400 West Beijing Road, Shanghai, 200040, People's Republic of China.
- Key Lab of Medical Embryo Molecular Biology, Ministry of Health, China, Shanghai Lab of Embryo and Reproduction Engineering, Shanghai, People's Republic of China.
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Petruzzelli R, Gaudino S, Amendola G, Sessa R, Puzone S, Di Concilio R, d'Urzo G, Amendolara M, Izzo P, Grosso M. Role of the cold shock domain protein A in the transcriptional regulation of HBG expression. Br J Haematol 2010; 150:689-99. [PMID: 20636440 DOI: 10.1111/j.1365-2141.2010.08303.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Impaired switching from fetal haemoglobin (HbF) to adult globin gene expression leads to hereditary persistence of fetal haemoglobin (HPFH) in adult life. This is of prime interest because elevated HbF levels ameliorate β-thalassaemia and sickle cell anaemia. Fetal haemoglobin levels are regulated by complex mechanisms involving factors linked or not to the β-globin gene (HBB) locus. To search for factors putatively involved in the expression of the γ-globin genes (HBG1, HBG2), we examined the reticulocyte transcriptome of three siblings who had different HbF levels and different degrees of β-thalassaemia severity although they had the same ΗBA- and ΗΒB cluster genotypes. By mRNA differential display we isolated the cDNA coding for the cold shock domain protein A (CSDA), also known as dbpA, previously reported to interact in vitro with the HBG2 promoter. Expression studies performed in K562 and in primary erythroid cells showed an inverse relationship between HBG and CSDA expression levels. Functional studies performed by Chromatin Immunoprecipitation and reporter gene assays in K562 cells demonstrated that CSDA is able to bind the HBG2 promoter and suppress its expression. Therefore, our study demonstrated that CSDA is a trans-acting repressor factor of HBG expression and modulates the HPFH phenotype.
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Affiliation(s)
- Raffaella Petruzzelli
- Dipartimento di Biochimica e Biotecnologie Mediche, Università degli Studi di Napoli Federico II, Naples, Italy
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30
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Halvorsen M, Martin JS, Broadaway S, Laederach A. Disease-associated mutations that alter the RNA structural ensemble. PLoS Genet 2010; 6:e1001074. [PMID: 20808897 PMCID: PMC2924325 DOI: 10.1371/journal.pgen.1001074] [Citation(s) in RCA: 244] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2010] [Accepted: 07/15/2010] [Indexed: 12/28/2022] Open
Abstract
Genome-wide association studies (GWAS) often identify disease-associated mutations in intergenic and non-coding regions of the genome. Given the high percentage of the human genome that is transcribed, we postulate that for some observed associations the disease phenotype is caused by a structural rearrangement in a regulatory region of the RNA transcript. To identify such mutations, we have performed a genome-wide analysis of all known disease-associated Single Nucleotide Polymorphisms (SNPs) from the Human Gene Mutation Database (HGMD) that map to the untranslated regions (UTRs) of a gene. Rather than using minimum free energy approaches (e.g. mFold), we use a partition function calculation that takes into consideration the ensemble of possible RNA conformations for a given sequence. We identified in the human genome disease-associated SNPs that significantly alter the global conformation of the UTR to which they map. For six disease-states (Hyperferritinemia Cataract Syndrome, β-Thalassemia, Cartilage-Hair Hypoplasia, Retinoblastoma, Chronic Obstructive Pulmonary Disease (COPD), and Hypertension), we identified multiple SNPs in UTRs that alter the mRNA structural ensemble of the associated genes. Using a Boltzmann sampling procedure for sub-optimal RNA structures, we are able to characterize and visualize the nature of the conformational changes induced by the disease-associated mutations in the structural ensemble. We observe in several cases (specifically the 5′ UTRs of FTL and RB1) SNP–induced conformational changes analogous to those observed in bacterial regulatory Riboswitches when specific ligands bind. We propose that the UTR and SNP combinations we identify constitute a “RiboSNitch,” that is a regulatory RNA in which a specific SNP has a structural consequence that results in a disease phenotype. Our SNPfold algorithm can help identify RiboSNitches by leveraging GWAS data and an analysis of the mRNA structural ensemble. Genome-wide association studies identify mutations in the human genome that correlate with a particular disease. It is common to find mutations associated with disease in the non-coding region of the genome. These non-coding mutations are more difficult to interpret at a molecular level, because they do not affect the protein sequence. In this study, we analyze disease-associated mutations in non-coding regions of our genome in the context of their structural effect on the message of genetic information in our cells, Ribonucleic Acid (RNA). We focus in particular on the regulatory parts of our genes known as untranslated regions. We find that certain disease-associated mutations in these regulatory untranslated regions have a significant effect on the structure of the RNA message. We call these elements “RiboSNitches,” because they act like switches turning on and off genes, but are caused by Single Nucleotide Polymorphisms (SNPs), which are single point mutations in our genome. The RiboSNitches we identify are potentially a new class of pharmaceutical targets, as it is possible to change the structure of RNA with small drug-like molecules.
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Affiliation(s)
- Matthew Halvorsen
- Biomedical Sciences Department, University at Albany, Albany, New York, United States of America
| | - Joshua S. Martin
- Developmental Genetics and Bioinformatics, Wadsworth Center, Albany, New York, United States of America
| | - Sam Broadaway
- Developmental Genetics and Bioinformatics, Wadsworth Center, Albany, New York, United States of America
| | - Alain Laederach
- Biomedical Sciences Department, University at Albany, Albany, New York, United States of America
- Developmental Genetics and Bioinformatics, Wadsworth Center, Albany, New York, United States of America
- * E-mail:
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31
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Jawaid K, Wahlberg K, Thein SL, Best S. Binding patterns of BCL11A in the globin and GATA1 loci and characterization of the BCL11A fetal hemoglobin locus. Blood Cells Mol Dis 2010; 45:140-6. [DOI: 10.1016/j.bcmd.2010.05.006] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2010] [Accepted: 05/07/2010] [Indexed: 01/12/2023]
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32
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Cappellini MD, Musallam KM, Taher AT. Insight onto the pathophysiology and clinical complications of thalassemia intermedia. Hemoglobin 2010; 33 Suppl 1:S145-59. [PMID: 20001620 DOI: 10.3109/03630260903351528] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Our understanding of the molecular and pathophysiological mechanisms underlying the disease process in patients with thalassemia intermedia (TI) has substantially increased over the past decade. TI encompasses a wide clinical spectrum of beta-thalassemia phenotypes. Some TI patients are asymptomatic until adult life, whereas others are symptomatic from as young as 2 years. A number of clinical complications commonly associated with TI are rarely seen in thalassemia major, including extramedullary hematopoiesis, leg ulcers, gallstones, thrombosis, and pulmonary hypertension. There are a number of options currently available for managing patients with TI, including transfusion therapy, iron chelation therapy, modulation of fetal hemoglobin production, and hematopoietic stem cell transplantation. However, at present, there are no clear guidelines for an orchestrated optimal treatment plan.
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33
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Chen W, Zhang X, Shang X, Cai R, Li L, Zhou T, Sun M, Xiong F, Xu X. The molecular basis of beta-thalassemia intermedia in southern China: genotypic heterogeneity and phenotypic diversity. BMC MEDICAL GENETICS 2010; 11:31. [PMID: 20181291 PMCID: PMC2845123 DOI: 10.1186/1471-2350-11-31] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2009] [Accepted: 02/25/2010] [Indexed: 12/31/2022]
Abstract
Background The clinical syndrome of thalassemia intermedia (TI) results from the β-globin genotypes in combination with factors to produce fetal haemoglobin (HbF) and/or co-inheritance of α-thalassemia. However, very little is currently known of the molecular basis of Chinese TI patients. Methods We systematically analyzed and characterized β-globin genotypes, α-thalassemia determinants, and known primary genetic modifiers linked to the production of HbF and the aggravation of α/β imbalance in 117 Chinese TI patients. Genotype-phenotype correlations were analyzed based on retrospective clinical observations. Results A total of 117 TI patients were divided into two major groups, namely heterozygous β-thalassemia (n = 20) in which 14 were characterized as having a mild TI with the Hb levels of 68-95 g/L except for five co-inherited αααanti-3.7 triplication and one carried a dominant mutation; and β-thalassemia homozygotes or compound heterozygotes for β-thalassemia and other β-globin defects in which the β+-thalassemia mutation was the most common (49/97), hemoglobin E (HbE) variants was second (27/97), and deletional hereditary persistence of fetal hemoglobin (HPFH) or δβ-thalassemia was third (11/97). Two novel mutations, Term CD+32(A→C) and Cap+39(C→T), have been detected. Conclusions Chinese TI patients showed considerable heterogeneity, both phenotypically and genotypically. The clinical outcomes of our TI patients were mostly explained by the genotypes linked to the β- and α-globin gene cluster. However, for a group of 14 patients (13 β0/βN and 1 β+/βN) with known heterozygous mutations of β-thalassemia and three with homozygous β-thalassemia (β0/β0), the existence of other causative genetic determinants is remaining to be molecularly defined.
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Affiliation(s)
- Wanqun Chen
- Department of Medical Genetics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, Guangdong 510515, China
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34
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35
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Thein SL, Menzel S, Lathrop M, Garner C. Control of fetal hemoglobin: new insights emerging from genomics and clinical implications. Hum Mol Genet 2009; 18:R216-23. [PMID: 19808799 PMCID: PMC2758709 DOI: 10.1093/hmg/ddp401] [Citation(s) in RCA: 183] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2009] [Accepted: 08/18/2009] [Indexed: 11/14/2022] Open
Abstract
Increased levels of fetal hemoglobin (HbF, alpha(2)gamma(2)) are of no consequence in healthy adults, but confer major clinical benefits in patients with sickle cell anemia (SCA) and beta thalassemia, diseases that represent major public health problems. Inter-individual HbF variation is largely genetically controlled, with one extreme caused by mutations involving the beta globin gene (HBB) complex, historically referred to as pancellular hereditary persistence of fetal hemoglobin (HPFH). These Mendelian forms of HPFH are rare and do not explain the common form of heterocellular HPFH which represents the upper tail of normal HbF variation, and is clearly inherited as a quantitative genetic trait. Genetic studies have identified three major quantitative trait loci (QTLs) (Xmn1-HBG2, HBS1L-MYB intergenic region on chromosome 6q23, and BCL11A on chromosome 2p16) that account for 20-50% of the common variation in HbF levels in patients with SCA and beta thalassemia, and in healthy adults. Two of the major QTLs include oncogenes, emphasizing the importance of cell proliferation and differentiation as an important contribution to the HbF phenotype. The review traces the story of HbF quantitative genetics that uncannily mirrors the changing focus in genetic methodology, from candidate genes through positional cloning, to genome-wide association, that have expedited the dissection of the genetic architecture underlying HbF variability. These genetic results have already provided remarkable insights into molecular mechanisms that underlie the hemoglobin 'switch'.
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Affiliation(s)
- Swee Lay Thein
- Division of Gene and Cell Based Therapy, King's College London School of Medicine, Molecular Haematology, Denmark Hill Campus, London SE5 9NU, UK.
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36
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Thalassaemia intermedia: an update. Mediterr J Hematol Infect Dis 2009; 1:e2009004. [PMID: 21415986 PMCID: PMC3033165 DOI: 10.4084/mjhid.2009.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2009] [Accepted: 08/19/2009] [Indexed: 01/29/2023] Open
Abstract
Our understanding of the molecular and pathophysiological mechanisms underlying the disease process in patients with thalassaemia intermedia (TI) has substantially increased over the past decade. TI encompasses a wide clinical spectrum of beta-thalassaemia phenotypes. Some TI patients are asymptomatic until adult life, whereas others are symptomatic from as young as 2 years of age. A number of clinical complications commonly associated with TI are rarely seen in thalassaemia major, including extramedullary hematopoiesis, leg ulcers, gallstones, thrombosis and pulmonary hypertension. There are a number of options currently available for managing patients with TI, including transfusion therapy, iron chelation therapy, modulation of foetal haemoglobin production and haematopoietic stem cell transplantation. However, at present, there are no clear guidelines for an orchestrated optimal treatment plan.
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37
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Jacquette A, Le Roux G, Lacombe C, Goossens M, Pissard S. Compound Heterozygosity for Two New Mutations in the β‐Globin Gene [Codon 9 (+ TA) and Polyadenylation Site (AATAAA→AAAAAA)] Leads to Thalassemia Intermedia in a Tunisian Patient. Hemoglobin 2009; 28:243-8. [PMID: 15481893 DOI: 10.1081/hem-120040304] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
More than 200 mutations that are associated with beta-thalassemia (thal) have been found. In most cases, studies to detect a mutation in a patient is made easier because of the existence of geographical sets of mutations that allow the use of a dedicated mutation detection kit. We describe here a patient who originated from Tunisia, in whom we found two as yet unreported mutations, showing that even in a well-studied population a full gene study might be needed to characterize mutation(s).
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Affiliation(s)
- Aurelia Jacquette
- Laboratoire de Biochimie et de Génétique, Hôpital Henri Mondor, Créteil, France
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38
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The HBS1L-MYB intergenic interval associated with elevated HbF levels shows characteristics of a distal regulatory region in erythroid cells. Blood 2009; 114:1254-62. [DOI: 10.1182/blood-2009-03-210146] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Abstract
HBS1L-MYB intergenic polymorphism (HMIP) on chromosome 6q23 is associated with elevated fetal hemoglobin levels and has pleiotropic effects on several hematologic parameters. To investigate potential regulatory activity in the region, we have measured sensitivity of the sequences to DNase I cleavage that identified 3 tissue-specific DNase I hypersensitive sites in the core intergenic interval. Chromatin immunoprecipitation with microarray (ChIP-chip) analysis showed strong histone acetylation in a defined interval of 65 kb corresponding to the core HBS1L-MYB intergenic region in primary human erythroid cells but not in non–MYB-expressing HeLa cells. ChIP-chip analysis also identified several potential cis-regulatory elements as strong GATA-1 signals that coincided with the DNase I hypersensitive sites present in MYB-expressing erythroid cells. We suggest that HMIP contains regulatory sequences that could be important in hematopoiesis by controlling MYB expression. This study provides the functional link between genetic association of HMIP with control of fetal hemoglobin and other hematologic parameters. We also present a large-scale analysis of histone acetylation as well as RNA polymerase II and GATA-1 interactions on chromosome 6q, and α and β globin gene loci. The data suggest that GATA-1 regulates numerous genes of various functions on chromosome 6q.
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39
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40
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Verma IC, Kleanthous M, Saxena R, Fucharoen S, Winichagoon P, Raizuddin S, Khan SN, Akbari MT, Izadyar M, Kotea N, Old JM, Ioannou PA, Khan B. Multicenter Study of the Molecular Basis of Thalassemia Intermedia in Different Ethnic Populations. Hemoglobin 2009; 31:439-52. [DOI: 10.1080/03630260701641245] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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41
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Akbari MT, Izadi P, Izadyar M, Kyriacou K, Kleanthous M. Molecular Basis of Thalassemia Intermedia in Iran. Hemoglobin 2009; 32:462-70. [DOI: 10.1080/03630260802341851] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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42
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Kornblit B, Taaning P, Birgens H. β-Thalassemia Due to a Novel Nonsense Mutation at Codon 37 (TGG→TAG) Found in an Afghanistani Family. Hemoglobin 2009; 29:209-13. [PMID: 16114184 DOI: 10.1081/hem-200066319] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
We have identified and characterized a novel beta-thalassemic mutation in an Afghanistanifamily. The molecular pathology consists of a single base substitution (TGG-->TAG) at codon 37 of the beta-globin gene, giving rise to a stop codon (TAG). Premature stop of translation results in a truncated protein and usually the phenotype of beta-thalassemia (thal) major in homozygous individuals. However, this was not the case in our proband, who was homozygous for the codon 37 mutation. He presented with the phenotype of thalassemia intermedia with a hemoglobin (Hb) level of 8.1 g/dL and no previous history of blood transfusions. High performance liquid chromatography (HPLC) analysis showed exclusively Hb F except for a Hb A2 level within normal limits. Subsequent analysis demonstrated homozygosity for the XmnI Ggamma polymorphism and heterozygosity for a deletional alpha-thal (alphaalpha/-alpha(-3.7)). These findings might, at least partly, explain the beta-thal intermedia phenotype observed in the proband.
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Affiliation(s)
- Brian Kornblit
- Department of Haematology, Herlev University Hospital, Center for Haemoglobin Disorders, Herlev, Denmark
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43
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Thein SL, Menzel S. Discovering the genetics underlying foetal haemoglobin production in adults. Br J Haematol 2009; 145:455-67. [DOI: 10.1111/j.1365-2141.2009.07650.x] [Citation(s) in RCA: 151] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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44
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Al-Allawi NAS, Badi AIA, Imanian H, Nikzat N, Jubrael JMS, Najmabadi H. Molecular characterization of alpha-thalassemia in the Dohuk region of Iraq. Hemoglobin 2009; 33:37-44. [PMID: 19205971 DOI: 10.1080/03630260802626053] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The molecular basis of alpha-thalassemia (alpha-thal) has been addressed by several studies from the eastern Mediterranean region, but not from Iraq. To address this issue, we studied 51 individuals with unexplained hypochromia and/or microcytosis, as well as nine patients with documented Hb H disease from the Dohuk region in northern Iraq. We used multiplex gap-polymerase chain reaction (gap-PCR), reverse hybridization, and sequencing for this purpose. It was found that the most common genotypes in those with unexplained hypochromia and/or microcytosis were -alpha(3.7)/alpha alpha, followed by - -(MED-I)/alpha alpha, then -alpha(3.7)/-alpha (3.7), respectively, detected in 84.3% of the above individuals. Other genotypes identified sporadically were -alpha(4.2)/alpha alpha, alpha(poly A1)alpha/alpha alpha (AATAAA>AATAAG), alpha(Adana)alpha/alpha alpha [Hb Adana, codon 59 (Gly-->Asp) or HBA1:c.179G>A], and alpha(Evanston)alpha/alpha alpha [Hb Evanston, codon 14 (Trp-->Arg) or HBA1:c.43 T>C]. Three cases (5.88%) remained uncharacterized even after sequencing. All nine Hb H cases carried the -alpha(3.7)/- -(MED-I) genotype. Such findings are rather different from those in other eastern Mediterranean populations, particularly with relevance to an Hb H molecular basis.
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Affiliation(s)
- Nasir A S Al-Allawi
- Department of Pathology, College of Medicine, University of Dohuk, Dohuk, Iraq.
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45
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Olivieri NF, Muraca GM, O'Donnell A, Premawardhena A, Fisher C, Weatherall DJ. Studies in haemoglobin E beta-thalassaemia. Br J Haematol 2008; 141:388-97. [PMID: 18410572 DOI: 10.1111/j.1365-2141.2008.07126.x] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Haemoglobin E beta-thalassaemia is the commonest form of severe thalassaemia in many Asian countries, but little is known about its natural history, the reasons for its clinical diversity, or its optimal management. Despite its frequency, haemoglobin E beta-thalassaemia is often managed in an ill-defined and haphazard way, usually by demand transfusion. We studied a cohort of Sri Lankan patients with haemoglobin E beta-thalassaemia over 5 years, and identified several genetic and environmental factors possibly contributing to the phenotypic diversity of the disorder. These included modifiers of haemoglobin F production, malaria and age-related changes in adaptation to anaemia. Our findings suggest that in many patients, haemoglobin E beta-thalassaemia can be managed without transfusion, even with low haemoglobin levels. Age-related changes in the pattern of adaptation to anaemia suggest that more cost-effective approaches to management should be explored.
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Affiliation(s)
- Nancy F Olivieri
- Hemoglobinopathy Research Program, Toronto General Hospital, University of Toronto, Toronto, ON, Canada.
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46
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Abstract
Identification of the molecular basis of the beta-thalassaemias and sickle cell disease (SCD) has made it clear that patients with the same beta-globin genotypes can have very variable patterns of clinical expression. Extensive biochemical and pathophysiological studies over the last 50 years have derived two major modifiers--innate ability to produce fetal haemoglobin and co-inheritance of alpha-thalassaemia, subsequently validated by family and population studies. However, these two modifiers do not explain the full clinical spectrum. Genetic studies have been successful in identifying modifiers if the loci have a major clinical effect and if the genetic variants are common. It is possible that additional modifiers could be uncovered using genetic approaches but success will depend on large sample sizes of well-characterised patients with well-defined phenotypes. Since some of the complications, such as overt stroke in SCD, are relatively rare events, intermediate end-points that contribute to the phenotype, such as Transcranial Doppler velocity (a major predictor of stroke in SCD), could be integrated within the genetic analysis. Integrating multiplex genetic testing with clinical and laboratory data to generate predictive models shows potential, but such genetic approaches also require large datasets.
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Affiliation(s)
- Swee Lay Thein
- King's College London School of Medicine, Department of Haematological Medicine, King's College Hospital, London, UK.
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47
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Basran RK, Reiss UM, Luo HY, Ware RE, Chui DHK. Beta-thalassemia intermedia due to compound heterozygosity for two beta-globin gene promoter mutations, including a novel TATA box deletion. Pediatr Blood Cancer 2008; 50:363-6. [PMID: 16732578 DOI: 10.1002/pbc.20916] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
An 8-year-old African-American boy had a clinical history consistent with mild beta-thalassemia intermedia with moderate anemia, microcytosis, reticulocytosis, and splenomegaly. He was asymptomatic and did not require transfusion. At age 4 years, hemoglobin (Hb) electrophoresis showed Hb A = 37.8%, Hb A(2) = 5.0%, and Hb F = 56.1%. At age 8 years, he was diagnosed to be a compound heterozygote for two beta-globin gene promoter mutations, the relatively common nucleotide (nt) -88 C --> T mutation from the cap site, and a novel two-nucleotide (AA) deletion between nt -29 and -26 within the TATA box of the beta-globin gene. His mother and 14-year-old brother were simple heterozygotes for this novel (AA) deletion. Both heterozygotes had normal Hb level, borderline microcytosis, and elevated Hb A(2).
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Affiliation(s)
- Raveen K Basran
- Hemoglobin Diagnostic Reference Laboratory, Boston Medical Center, Boston, Massachusetts, USA
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48
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Garewal G, Das R, Awasthi A, Ahluwalia J, Marwaha RK. The clinical significance of the spectrum of interactions of CAP+1 (A→C), a silent β-globin gene mutation, with other β-thalassemia mutations and globin gene modifiers in north Indians. Eur J Haematol 2007; 79:417-21. [PMID: 17900295 DOI: 10.1111/j.1600-0609.2007.00958.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
OBJECTIVES To assess the clinical significance of the interactions of CAP+1 (A-->C), a silent beta-globin gene mutation, with other beta-thalassemia mutations and globin gene modifiers in north Indians. METHODS The clinical phenotypes associated with compound heterozygosity for the CAP+1 (A-->C) mutation with other beta-thalassemia mutations, together with the potential effect of the genetic modifiers alpha-thalassemia and the Xmn-1(G)gamma C-->T polymorphism were studied in 30 patients. The frequency of the CAP+1 (A-->C) polymorphism was determined and an analysis of the red cell indices, HbA(2) levels, iron status, and alpha-globin genes was carried out in 35 heterozygotes. RESULTS Based on an analysis of 1075 beta-thalassemia alleles the CAP+1 (A-->C) mutation constituted 3.2% of north Indians. There was a wide spectrum of phenotypic severity in compound heterozygotes; 18 of 30 were transfusion dependent. There was a very high frequency of the -/- genotype of the Xmn-1(G)gamma polymorphism in compound heterozygotes. Analysis of 35 heterozygotes indicated that approximately half were hematologically normal and therefore genuine 'silent' carriers. CONCLUSIONS Compound heterozygotes for CAP+1 (A-->C) and other severe beta-thalassemia alleles are phenotypically severe enough to necessitate appropriate therapy and counseling. The unexpected severity of these interactions may be due, in part, to the high frequency of beta-thalassemia alleles associated with the Xmn-1(G)gamma- allele in Indian populations. It is concluded that the CAP+1 (A-->C) mutation can pose serious difficulties in screening and counseling programs in populations in which it occurs at a significant frequency.
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Affiliation(s)
- Gurjeewan Garewal
- Department of Haematology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
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49
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Thein SL, Menzel S, Peng X, Best S, Jiang J, Close J, Silver N, Gerovasilli A, Ping C, Yamaguchi M, Wahlberg K, Ulug P, Spector TD, Garner C, Matsuda F, Farrall M, Lathrop M. Intergenic variants of HBS1L-MYB are responsible for a major quantitative trait locus on chromosome 6q23 influencing fetal hemoglobin levels in adults. Proc Natl Acad Sci U S A 2007; 104:11346-51. [PMID: 17592125 PMCID: PMC2040901 DOI: 10.1073/pnas.0611393104] [Citation(s) in RCA: 242] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2006] [Indexed: 12/21/2022] Open
Abstract
Individual variation in fetal hemoglobin (HbF, alpha(2)gamma(2)) response underlies the remarkable diversity in phenotypic severity of sickle cell disease and beta thalassemia. HbF levels and HbF-associated quantitative traits (e.g., F cell levels) are highly heritable. We have previously mapped a major quantitative trait locus (QTL) controlling F cell levels in an extended Asian-Indian kindred with beta thalassemia to a 1.5-Mb interval on chromosome 6q23, but the causative gene(s) are not known. The QTL encompasses several genes including HBS1L, a member of the GTP-binding protein family that is expressed in erythroid progenitor cells. In this high-resolution association study, we have identified multiple genetic variants within and 5' to HBS1L at 6q23 that are strongly associated with F cell levels in families of Northern European ancestry (P = 10(-75)). The region accounts for 17.6% of the F cell variance in northern Europeans. Although mRNA levels of HBS1L and MYB in erythroid precursors grown in vitro are positively correlated, only HBS1L expression correlates with high F cell alleles. The results support a key role for the HBS1L-related genetic variants in HbF control and illustrate the biological complexity of the mechanism of 6q QTL as a modifier of fetal hemoglobin levels in the beta hemoglobinopathies.
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Affiliation(s)
- Swee Lay Thein
- King's College London School of Medicine, Division of Gene and Cell Based Therapy, King's College Hospital, London SE5 9PJ, United Kingdom.
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Tripatara A, Jetsrisuparb A, Teeratakulpisarn J, Kuaha K. Hemostatic alterations in splenectomized and non-splenectomized patients with β-thalassemia/hemoglobin E disease. Thromb Res 2007; 120:805-10. [PMID: 17382994 DOI: 10.1016/j.thromres.2007.02.006] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2006] [Revised: 01/23/2007] [Accepted: 02/11/2007] [Indexed: 01/28/2023]
Abstract
Beta-thalassemia/hemoglobin (Hb) E is a hereditary hemolytic anemia with varying degrees of severity. Severely affected patients are treated with blood transfusion and/or splenectomy in order to maintain an optimum level of hemoglobin for normal growth and physical activities. As thrombosis has been observed among splenectomized patients, we have investigated alterations in coagulation and fibrinolysis in beta-thalassemia/Hb E patients. Plasma levels of prothrombin, fibrinogen, factors V, VII, VIII, IX and XI, protein C, protein S, thrombin activatable fibrinolysis inhibitor (TAFI) and prothrombin fragment 1+2 were determined in 61 patients (21 non-severe non-splenectomized, 18 severe non-splenectomized, 22 severe splenectomized) and 28 healthy individuals. Serum levels of D-dimer, ferritin, aspartate transaminase and alanine transaminase were also measured. All severe patients received regular blood transfusion. Prothrombin fragment 1+2 and D-dimer were significantly elevated in splenectomized patients compared to the healthy control subjects, whereas levels of proteins C, protein S, TAFI, fibrinogen, and factors V and VIII in the splenectomized groups were statistically lower than those in control group. There are no statistical differences for the other parameters measured between patients and controls. Coagulation tests showed only significantly reduction in TAFI and factor V and VIII levels in severe splenectomized group in comparison with severe non-splenectomized patients. These results demonstrate the existence of a low grade consumptive coagulopathy among blood-transfused splenectomized patients with severe clinical manifestations, indicating that these patients may have a higher risk for thrombosis than comparable patients with intact spleen.
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Affiliation(s)
- Amporn Tripatara
- Division of Medical Technology, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, 40002, Thailand.
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