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Dabke P, Colah R, Ghosh K, Nadkarni A. Effect of Cis Acting Potential Regulators in the β Globin Gene Cluster on the Production of HbF in Thalassemia Patients. Mediterr J Hematol Infect Dis 2013; 5:e2013012. [PMID: 23505600 PMCID: PMC3591280 DOI: 10.4084/mjhid.2013.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Accepted: 01/10/2013] [Indexed: 11/08/2022] Open
Abstract
The clinical presentation of β-thalassemia intermedia phenotypes are influenced by many factors. The persistence of fetal hemoglobin and several polymorphisms located in the promoters of γ- and β-globin genes are some of them. The aim of this study was to evaluate the combined effect of the -158 Gγ (C→T) polymorphism and of the (AT)x(T)y configuration, as well as their eventual association with elevated levels of HbF in β-thalassemia carriers, β-thalassemia intermedia, β-thalassemia major and normal controls of Indian origin. The -158 Gγ T allele was found to be associated with increased levels of HbF in β thalassemia carriers, and not in wild-type subjects. In the homozygous group, the -158 Gγ T allele was significantly higher in the thalassemia intermedia group (66%) as against the thalassemia major group (21%). The (AT)9(T)5 allele did not show any association with raised HbF levels. However 24% of milder cases showed presence of this allele. This study suggests that two regions of the β globin cluster, whether in cis or in trans to each other, can interact to enhance HbF expression when a β thalassemic determinant is present in heterozygosity and help in amelioration of the severity of the disease in homozygotes.
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Affiliation(s)
- Pooja Dabke
- National Institute of Immunohaematology (ICMR), 13th Floor, New Multistoried Building, K.E.M. Hospital Campus, Parel, Mumbai –4000 12
| | - Roshan Colah
- National Institute of Immunohaematology (ICMR), 13th Floor, New Multistoried Building, K.E.M. Hospital Campus, Parel, Mumbai –4000 12
| | - Kanjaksha Ghosh
- National Institute of Immunohaematology (ICMR), 13th Floor, New Multistoried Building, K.E.M. Hospital Campus, Parel, Mumbai –4000 12
| | - Anita Nadkarni
- National Institute of Immunohaematology (ICMR), 13th Floor, New Multistoried Building, K.E.M. Hospital Campus, Parel, Mumbai –4000 12
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Dabke P, Colah RB, Ghosh K, Nadkarni A. Effect of a group of genetic markers around the 5' regulatory regions of the β globin gene cluster linked to high HbF on the clinical severity of β thalassemia. Blood Cells Mol Dis 2012; 50:156-60. [PMID: 23211376 DOI: 10.1016/j.bcmd.2012.11.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Revised: 10/30/2012] [Accepted: 11/03/2012] [Indexed: 10/27/2022]
Abstract
The clinical and hematological course of β thalassemia intermedia is influenced by a number of genetic factors which play a role in increasing fetal haemoglobin levels. Several polymorphisms located in the promoters of β and γ globin gene are involved in influencing the disease severity. Our objective was to study the effect of cis-DNA haplotypes, motifs, or polymorphisms (Pre G γ globin gene haplotypes, Aγ-δ intergenic region haplotypes XmnI and (AT)(x)(T)(y) polymorphisms, β-LCR HS2 and HS3 site motifs) that may contribute to higher HbF levels and a milder clinical course. We found that a combination of T haplotype of the Aγ-δ intergenic region, TAG Pre-Gγ haplotype, presence of the XmnI polymorphism along with the (AT)(9)(T)(5) motif constitutes a topography that co-relates with raised HbF levels which may contribute in ameliorating the disease severity.
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Affiliation(s)
- Pooja Dabke
- National Institute of Immunohaematology (ICMR), 13th Floor, New Multistoried Building, K.E.M. Hospital Campus, Parel, Mumbai 4000 12, India
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SHANG X, RAO Z, LOU J, LI W, XIONG F, ZHOU HP, XU X. Compound heterozygosity for a rare small deletion and a common point mutation in the beta-globin gene: report of two Chinese families. Int J Lab Hematol 2010; 33:79-84. [DOI: 10.1111/j.1751-553x.2010.01253.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Solovieff N, Milton JN, Hartley SW, Sherva R, Sebastiani P, Dworkis DA, Klings ES, Farrer LA, Garrett ME, Ashley-Koch A, Telen MJ, Fucharoen S, Ha SY, Li CK, Chui DHK, Baldwin CT, Steinberg MH. Fetal hemoglobin in sickle cell anemia: genome-wide association studies suggest a regulatory region in the 5' olfactory receptor gene cluster. Blood 2010; 115:1815-22. [PMID: 20018918 PMCID: PMC2832816 DOI: 10.1182/blood-2009-08-239517] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2009] [Accepted: 11/18/2009] [Indexed: 11/20/2022] Open
Abstract
In a genome-wide association study of 848 blacks with sickle cell anemia, we identified single nucleotide polymorphisms (SNPs) associated with fetal hemoglobin concentration. The most significant SNPs in a discovery sample were tested in a replication set of 305 blacks with sickle cell anemia and in subjects with hemoglobin E or beta thalassemia trait from Thailand and Hong Kong. A novel region on chromosome 11 containing olfactory receptor genes OR51B5 and OR51B6 was identified by 6 SNPs (lowest P = 4.7E-08) and validated in the replication set. An additional olfactory receptor gene, OR51B2, was identified by a novel SNP set enrichment analysis. Genome-wide association studies also validated a previously identified SNP (rs766432) in BCL11A, a gene known to affect fetal hemoglobin levels (P = 2.6E-21) and in Thailand and Hong Kong subjects. Elements within the olfactory receptor gene cluster might play a regulatory role in gamma-globin gene expression.
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MESH Headings
- Adolescent
- Adult
- Black or African American/genetics
- Anemia, Sickle Cell/blood
- Anemia, Sickle Cell/genetics
- Carrier Proteins/genetics
- Child
- Child, Preschool
- Chromosomes, Human, Pair 11/genetics
- Chromosomes, Human, X/genetics
- Female
- Fetal Hemoglobin/genetics
- Fetal Hemoglobin/metabolism
- Genome-Wide Association Study
- Hemoglobin E/genetics
- Hong Kong
- Humans
- Male
- Multigene Family
- Nuclear Proteins/genetics
- Polymorphism, Single Nucleotide
- Receptors, Odorant/genetics
- Regulatory Sequences, Nucleic Acid
- Repressor Proteins
- Thailand
- Young Adult
- beta-Thalassemia/genetics
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Affiliation(s)
- Nadia Solovieff
- Department of Biostatistics, Boston University School of Public Health, MA, USA
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Arya V, Agarwal S, Pradhan M. Association of polymorphic pattern of the (AT) × (T)y motif of β-globin gene in North Indian thalassemia patients with variable clinical expression. Indian J Hematol Blood Transfus 2010; 26:21-3. [PMID: 23100997 DOI: 10.1007/s12288-010-0008-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2008] [Accepted: 01/24/2009] [Indexed: 10/19/2022] Open
Abstract
Among the polymorphic genetic markers of the β-globin gene cluster, the (AT) × (T)y motif and a common C→T variation at -158 of the Gγ globin gene were investigate din 20 β-thalassemia IVSI-5 (G→C) homozygous patients with variable clinical manifestation and 10 normal subjects from north India to deduce any association with the co-inherited genetic polymorphism. We found (AT)(7)(T)(7) repeat motif in all the 20 chromosomes of normal subjects and two different sequence configuration(AT)(8)(T)(5), (AT)(9)(T)(5) in the patient group whereas the presence of -158(C→T) Gγ was quite polymorphic. We conclude that polymorphism -158(C→T) Gγ and (AT) × (T)y sequence variation other than (AT)(7)(T)(7) could influence the phenotype by increasing Hb F expression.
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Affiliation(s)
- Vandana Arya
- Department of Genetics, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, Uttar Pradesh India
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Gazouli M, Katsantoni E, Kosteas T, Anagnou NP. Persistent fetal gamma-globin expression in adult transgenic mice following deletion of two silencer elements located 3' to the human Agamma-globin gene. Mol Med 2009; 15:415-24. [PMID: 19690621 DOI: 10.2119/molmed.2009.00019] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2009] [Accepted: 08/10/2009] [Indexed: 12/19/2022] Open
Abstract
Natural deletions of the human gamma-globin gene cluster lead to specific syndromes characterized by increased production of fetal hemoglobin in adult life and provide a useful model to delineate novel cis-acting elements involved in the developmental control of hemoglobin switching. A hypothesis accounting for these phenotypic features assumes that silencers located within the Agamma-to delta-gene region are deleted in hereditary persistence of fetal hemoglobin (HPFH) and deltabeta-thalassemias, leading to failure of switching. In the present study, we sought to clarify the in vivo role of two elements, termed Enh and F, located 3' to the Agamma-globin, in silencing the fetal genes. To this end, we generated three transgenic lines using cosmid constructs containing the full length of the globin locus control region (LCR) linked to the 3.3-kb Agamma-gene lacking both the Enh and F elements. The Enh/F deletion resulted in high levels of Agamma-globin gene expression in adult mice in all single copy lines, whereas, the LCR-Agamma single copy lines which retain the Enh and F elements exhibited complete normal switching of the fetal Agamma-gene. Our study documents directly for the first time the in vivo role of these two gene-proximal negative regulatory elements in silencing the fetal globin gene in the perinatal period, and thus these data may permit their eventual exploitation in therapeutic approaches for thalassemias.
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Affiliation(s)
- Maria Gazouli
- Laboratory of Biology, University of Athens School of Medicine, Athens, Greece
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Molecular basis of deletional hereditary persistence of fetal hemoglobin and δβ-thalassemia in Indian patients. Clin Chim Acta 2008; 392:69-70. [DOI: 10.1016/j.cca.2008.02.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2008] [Revised: 02/18/2008] [Accepted: 02/19/2008] [Indexed: 11/20/2022]
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Abstract
Fetal hemoglobin (HbF), the predominant hemoglobin in the fetus, is a mixture of two molecular species (alpha(2)(G)gamma(2) and alpha(2)(A)gamma(2)) that differ only at position 136 reflecting the products of two nonallelic gamma-globin genes. At the time of birth, HbF accounts for approximately 70% of the total Hb. The (G)gamma:(A)gamma globin ratio in the HbF of normal newborn is 70:30 whereas in the trace amounts of HbF that is found in the adult it reverses to 40:60 because of a gamma- to beta-globin gene switch. Alterations of these ratios are indicative of a molecular defect at the level of the HbF synthesis. Qualitative hemoglobinopathies due to (G)gamma and (A)gamma chain structural variants, and quantitative hemoglobinopathies affecting the synthesis of HbF such as gamma-thalassemias, duplications, triplications, and even sextuplications of the gamma-globin genes, which may be detected in newborn blood lysates, have been described. Moreover, several pathological and nonpathological conditions affecting the beta-globin gene cluster, such as beta-thalassemia, sickle cell disease, deltabeta-thalassemia, and hereditary persistence of HbF syndromes, are characterized by the continued synthesis of gamma-globin chains in the adult life. Studies of these natural mutants associated with increased synthesis of HbF in adult life have provided considerable insight into the understanding of the control of globin gene expression and Hb switching.
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Affiliation(s)
- Laura Manca
- Department of Physiological, Biochemical and Cell Sciences, University of Sassari, Sassari, Italy
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Chan PK, Ma ESK, Philipsen S, Tan-Un KC. The study of sequence configuration and functional impact of the (AC)n(AT)xTy motif in human beta-globin gene promoter. Am J Hematol 2007; 82:342-8. [PMID: 17133428 DOI: 10.1002/ajh.20836] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
In this report we examine the (AC)n(AT)xTy motif residing -530 bp 5' upstream of the beta-globin gene in Chinese thalassaemic patients. This motif is a putative binding site for a repressor protein, termed beta protein 1 (BP1) (Berg et al., Nucleic Acids Res 1989;17:8833-8852). Variations in the (AC)n(AT)xTy repeats affect the binding affinity of BP1, thereby altering the expression of the beta-globin gene. Eight different configurations of this repeat motif are identified in our population of Chinese beta-thalassaemia patients. A (AC)3(AT)7T5 motif was identified among these thalassaemia patients and its influence in beta-globin gene expression was studied using stable transfection assay in murine erythroleukemia (MEL) cells. Our data demonstrated that the (AC)3(AT)7T5 motif has a moderately strong repressor effect on the expression of the cis-linked beta-globin gene. The high affinity of BP1 for this motif may result in the suppression of the transcription of the beta-globin gene (Berg et al., Am J Hematol 1991;36:42-47). We postulate that silencer elements in the beta-globin promoter play an important role in modifying the clinical presentation of the disease.
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Affiliation(s)
- P K Chan
- Department of Zoology, Kadoorie Biological Science Building, The University of Hong Kong, Hong Kong SAR, People's Republic of China
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Perry RT, Gearhart DA, Wiener HW, Harrell LE, Barton JC, Kutlar A, Kutlar F, Ozcan O, Go RCP, Hill WD. Hemoglobin binding to A beta and HBG2 SNP association suggest a role in Alzheimer's disease. Neurobiol Aging 2006; 29:185-93. [PMID: 17157413 PMCID: PMC2266611 DOI: 10.1016/j.neurobiolaging.2006.10.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2006] [Revised: 08/04/2006] [Accepted: 10/11/2006] [Indexed: 10/23/2022]
Abstract
From a normal human brain phage display library screen we identified the gamma (A)-globin chain of fetal hemoglobin (Hb F) as a protein that bound strongly to A beta1-42. We showed the oxidized form of adult Hb (metHb A) binds with greater affinity to A beta1-42 than metHb F. MetHb is more toxic than oxyhemoglobin because it loses its heme group more readily. Free Hb and heme readily damage vascular endothelial cells similar to Alzheimer's disease (AD) vascular pathology. The XmnI polymorphism (C-->T) at -158 of the gamma (G)-globin promoter region can contribute to increased Hb F expression. Using family-based association testing, we found a significant protective association of this polymorphism in the NIMH sibling dataset (n=489) in families, with at least two affected and one unaffected sibling (p=0.006), with an age of onset >50 years (p=0.010) and >65 years (p=0.013), and families not homozygous for the APOE4 allele (p=0.041). We hypothesize that Hb F may be less toxic than adult Hb in its interaction with A beta and may protect against the development of AD.
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Affiliation(s)
- Rodney T. Perry
- Department. of Epidemiology, University of Alabama at Birmingham, Birmingham, AL 35294-0022, USA; Birmingham, AL 35294-0022, ; ;
| | - Debra A. Gearhart
- Department of Pharmacology & Toxicology, Medical College of Georgia, Augusta , GA 30912-2300, USA;
| | - Howard W. Wiener
- Department. of Epidemiology, University of Alabama at Birmingham, Birmingham, AL 35294-0022, USA; Birmingham, AL 35294-0022, ; ;
| | - Lindy E. Harrell
- Alzheimer' Disease Center, Department of Neurology, University of Alabama at Birmingham, Birmingham, AL 35294-0017;
| | | | - Abdullah Kutlar
- Department of Medicine, Medical College of Georgia, Augusta GA 30912-2000 (USA); ;
| | - Ferdane Kutlar
- Department of Medicine, Medical College of Georgia, Augusta GA 30912-2000 (USA); ;
| | - Ozan Ozcan
- Department of Cellular Biology & Anatomy, Medical College of Georgia ; Department of Biology, Paine College, Augusta, GA 30912-2000;
| | - Rodney C. P. Go
- Department. of Epidemiology, University of Alabama at Birmingham, Birmingham, AL 35294-0022, USA; Birmingham, AL 35294-0022, ; ;
| | - William D. Hill
- Department of Cellular Biology and Anatomy, Department of Neurology, Institute of Molecular Medicine and Genetics, Medical College of Georgia; Augusta Veterans Administration Medical Center, Augusta, GA 30912-2000, USA;
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