Dissecting the role of genetic modifiers of hemoglobinopathies: A futuristic approach towards precision medicine

Abstract Introduction: Hemoglobinopathies though a monogenic disorder, show phenotypic variability. Hence, understanding the genetics underlying the heritable sub-phenotypes of hemoglobinopathies, specific to each population, would be prognostically useful and could inform personalized therapeutics. This study aimed to evaluate the role of genetic modifiers leading to higher HbF production with cumulative impact of the modifiers on disease severity. Materials and methods:200 patients [100 β-thalassemia homozygotes,100 Sickle Cell Anemia], and 50 healthy controls were recruited. Primary screening followed with molecular analysis for confirming the β-hemoglobinopathy was performed. Co-existing α-thalassemia and the polymorphisms located in 3 genetic loci linked to HbF regulation were screened.Results: The most remarkable result was the association of SNPs with clinically relevant phenotypic groups. The γ-globin gene promoter polymorphisms [-158 C→T,+25 G→A],BCL11A rs1427407 G→T,-3 bp HBS1L-MYB rs66650371 and rs9399137 T→C polymorphisms were correlated with higher HbF, in group that has lower disease severity score (P<0.00001), milder clinical presentation, and a significant delay in the age of the first transfusion.Conclusion:Our study emphasizes the complex genetic interactions underlying the disease phenotype that may be a prognostic marker for predicting the clinical severity and assist in disease management.

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Significance of genetic modifiers of hemoglobinopathies leading towards precision medicine

Scientific Reports ◽

10.1038/s41598-021-00169-x ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Priya Hariharan ◽

Manju Gorivale ◽

Pratibha Sawant ◽

Pallavi Mehta ◽

Anita Nadkarni

Keyword(s):

Disease Severity ◽

Phenotypic Variability ◽

Globin Gene ◽

Gene Promoter ◽

Clinical Severity ◽

Genetic Modifiers ◽

Promoter Polymorphisms ◽

Cumulative Impact ◽

Remarkable Result

AbstractHemoglobinopathies though a monogenic disorder, show phenotypic variability. Hence, understanding the genetics underlying the heritable sub-phenotypes of hemoglobinopathies, specific to each population, would be prognostically useful and could inform personalized therapeutics. This study aimed to evaluate the role of genetic modifiers leading to higher HbF production with cumulative impact of the modifiers on disease severity. 200 patients (100 β-thalassemia homozygotes, 100 Sickle Cell Anemia), and 50 healthy controls were recruited. Primary screening followed with molecular analysis for confirming the β-hemoglobinopathy was performed. Co-existing α-thalassemia and the polymorphisms located in 3 genetic loci linked to HbF regulation were screened. The most remarkable result was the association of SNPs with clinically relevant phenotypic groups. The γ-globin gene promoter polymorphisms [− 158 C → T, + 25 G → A],BCL11A rs1427407 G → T, − 3 bp HBS1L-MYB rs66650371 and rs9399137 T → C polymorphisms were correlated with higher HbF, in group that has lower disease severity score (P < 0.00001), milder clinical presentation, and a significant delay in the age of the first transfusion. Our study emphasizes the complex genetic interactions underlying the disease phenotype that may be a prognostic marker for predicting the clinical severity and assist in disease management.

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Searching for Disease Modifiers Genes in Thalassemia.

Blood ◽

10.1182/blood.v106.11.3642.3642 ◽

2005 ◽

Vol 106 (11) ◽

pp. 3642-3642

Author(s):

Suthat Fucharoen ◽

Orapan Sripichai ◽

Pranee Winichagoon ◽

Kenneth Abel ◽

Andreas Braun

Keyword(s):

Disease Severity ◽

Dna Analysis ◽

Genome Wide Association Study ◽

Globin Gene ◽

Fetal Hemoglobin ◽

Nucleotide Polymorphisms ◽

Genetic Modifiers ◽

Chromosome 11 ◽

Genotype Frequencies ◽

A Genome

Abstract β0-thalassemia/HbE disease is one of the most common thalassemias in Southeast Asia. Patients with compound heterozygote for HbE and β0 mutant alleles display remarkable variability in clinical expression, ranging from nearly asymptomatic to severe, transfusion-dependent disease. It is believed that additional genetic factors modifying disease severity may account for this variability. A universal platform technology (MassARRAY) based on mass spectrometry for analyzing nucleic acids at a high level of precision and accuracy has been developed. To identify genetic modifiers influencing severity among 1060 β0-thalassemia/HbE patients, we are utilizing this technology to conduct a genome-wide association study involving approximately 110,000 gene-based single nucleotide polymorphisms (SNPs). This assay panel corresponds to SNPs with a median spacing of 10.4 kilobases, in approximately 99% of all known and predicted human genes. DNAs from approximately 200 regionally matched patients representing the extremes of mild and severe cases were included in each DNA pool. Allele frequencies for all SNPs were estimated in both pools, and those showing suggestive significant differences (p values <0.02) were selected for verification by repeated pooled DNA analysis. Approximately one-fourth of these showed reproducible allelic differences at p<0.05, and more than 600 were selected for genotyping the individual patient DNAs in order to determine precise allele and genotype frequencies. A number of SNPs showed evidence for association with disease severity, including several in reported quantitative trait loci (QTLs) associated with fetal hemoglobin HbF levels. However the most strongly associated SNPs were within a region on chromosome 11 distinct from the beta globin gene cluster, within which most analysis to date has focused.

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Transcriptional role of a conserved GATA-1 site in the human epsilon-globin gene promoter.

Molecular and Cellular Biology ◽

10.1128/mcb.11.5.2558 ◽

1991 ◽

Vol 11 (5) ◽

pp. 2558-2566 ◽

Cited By ~ 41

Author(s):

Q H Gong ◽

J Stern ◽

A Dean

Keyword(s):

Globin Gene ◽

Point Mutations ◽

Gene Promoter ◽

Globin Genes ◽

Mobility Shift ◽

Dnase I Footprinting ◽

Nuclear Extracts ◽

Protein Dna Interactions ◽

Globin Promoter

The epsilon-globin gene is the first of the human beta-like globin genes to be expressed during development. We have analyzed protein-DNA interactions in the epsilon-globin promoter region by DNase I footprinting and electrophoretic mobility shift experiments using nuclear extracts from K562 human erythroid cells and from nonerythroid HeLa cells. A restricted set of ubiquitous proteins, including Sp1, bound to regions of the promoter including the CACCC and CCAAT sites. Three interactions, at positions -213, -165, and +3 relative to the transcription start site, were erythroid specific and corresponded to binding of GATA-1, a transcription factor highly restricted to the erythroid lineage. Interestingly, the GATA-1 site at -165 has been conserved in the promoters of 10 mammalian embryonic globin genes. Point mutations demonstrate that GATA-1 binding to this site is necessary for interaction with an erythroid-specific enhancer but that in the absence of an enhancer, GATA-1 does not increase transcription.

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Role of NF-Y in In Vivo Regulation of the γ-Globin Gene

Molecular and Cellular Biology ◽

10.1128/mcb.21.9.3083-3095.2001 ◽

2001 ◽

Vol 21 (9) ◽

pp. 3083-3095 ◽

Cited By ~ 36

Author(s):

Zhijun Duan ◽

George Stamatoyannopoulos ◽

Qiliang Li

Keyword(s):

Globin Gene ◽

Gene Promoter ◽

Transcriptional Factor ◽

Proximal Promoter ◽

Transcription Cofactor ◽

Basal Transcriptional Machinery ◽

Ccaat Box ◽

Chromatin Opening

ABSTRACT The duplicated CCAAT box is required for γ gene expression. We report here that the transcriptional factor NF-Y is recruited to the duplicated CCAAT box in vivo. A mutation of the duplicated CCAAT box that severely disrupts the NF-Y binding also reduces the accessibility level of the γ gene promoter, affects the assembly of basal transcriptional machinery, and increases the recruitment of GATA-1 to the locus control region (LCR) and the proximal promoter and the recruitment of transcription cofactor CBP/p300 to the LCR. These findings suggest that recruitment of NF-Y to the duplicated CCAAT box plays a role in the chromatin opening of the γ gene promoter as well as in the communication between the γ gene promoter and the LCR.

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Genotype - Phenotype Correlation Among Haemoglobin E β-thalassaemia Patients

10.21203/rs.3.rs-745185/v1 ◽

2021 ◽

Author(s):

Farin Masra ◽

Siti Razak ◽

Nor Murad ◽

Doris Chong ◽

C-Khai Loh ◽

...

Keyword(s):

Haemoglobin Level ◽

Globin Gene ◽

Cross Sectional Study ◽

Clinical Severity ◽

Genetic Modifiers ◽

Clinical Predictors ◽

Cross Sectional ◽

Gene Deletions ◽

Severity Scoring ◽

Severe Group

Abstract Background and objectives: Haemoglobin E β-thalassaemia has a variable clinical presentation. This study describes the clinical spectrum of these patients in two thalassaemia centers in Malaysia in addition to determining the prevalence of selected primary and secondary genetic modifiers which may influence its phenotype. Methods: A total of 99 patients were recruited in this cross-sectional study. Clinical parameters and severity scoring were determined. Molecular analysis was performed: Sanger sequencing and MLPA for β globin mutations; multiplex PCR for α-globin gene deletions and RFLP-PCR for XmnI polymorphism.Results: Patients with mild HbE β-thalassaemia were diagnosed at a later age as compared to the severe group (mean 3.14 and 1.6 years, p = 0.03). Haemoglobin level at diagnosis was higher for the mild group as compared to severe group (7.9 g/dL ± 1.97 and 6.0 g/dL ± 1.00, p = 0.02). The commonest β mutation in Malays were IVS1-5 (51.69%) and CD41/42 (20.2%) whereas in the Chinese, IVS2-654(44.4%) and CD41/42(33.4%). Single α-gene deletion (-α3.7/αα) was found in 4% of patients and none were homozygous for XmnI (+/+) polymorphism. Conclusion: Age at presentation and haemoglobin level at initial diagnosis is useful as clinical predictors of disease severity. The majority of our patients had β° gene mutation i.e. IVS1-5 and CD41/42, which accounted for the moderate to severe phenotype based on clinical severity scoring.

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Promoter Polymorphisms in the ATP Binding Cassette Transporter Gene Influence Production of Cell-Derived Microparticles and Are Highly Associated with Susceptibility to Severe Malaria in Humans

Infection and Immunity ◽

10.1128/iai.01175-12 ◽

2013 ◽

Vol 81 (4) ◽

pp. 1287-1294 ◽

Cited By ~ 7

Author(s):

Upasana Sahu ◽

Biranchi N. Mohapatra ◽

Shantanu K. Kar ◽

Manoranjan Ranjit

Keyword(s):

Severe Malaria ◽

Gene Promoter ◽

Clinical Severity ◽

Promoter Polymorphisms ◽

Content Type ◽

Abca1 Gene ◽

Flow Cytometric Method ◽

Mutant Variant ◽

Pair Method ◽

Abca1 Protein

ABSTRACTMicroparticle (MP) efflux is known to be mediated by the ABCA1 protein, and the plasma level of these cell-derived MPs is elevated considerably during human malarial infection. Therefore, two polymorphisms at positions −477 and −320 in the promoter of the ABCA1 gene were genotyped and tested for association with the plasma MP level in four groups of malaria patients segregated according to the clinical severity, i.e., cerebral malaria (CM), multiorgan dysfunction (MOD), noncerebral severe malaria, and uncomplicated malaria (UM). The TruCount tube-based flow cytometric method was used for the exact quantification of different cell-derived MPs in patients. Polymorphisms in the ABCA1 gene promoter were analyzed by use of the PCR/two-primer-pair method, followed by restriction fragment length polymorphism, in 428 malaria patients. The level of circulating plasma MPs was significantly higher in febrile patients withPlasmodium falciparuminfection, especially in CM patients compared to healthy individuals. The homozygous wild-type −477 and −320 genotype was observed to be significantly higher in patients with severe malaria. These patients also showed marked increases in the plasma MP numbers compared to UM patients. We report here for the first time an association of ABCA1 promoter polymorphisms with susceptibility to severe malaria, especially to CM and MOD, indicating the protective effect of the mutant variant of the polymorphism. We hypothesize that the −477T and −320G polymorphisms affect the downregulation of MP efflux and may be a predictor of organ complication duringP. falciparummalarial infections.

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Genetic association studies in β-hemoglobinopathies

Hematology ◽

10.1182/asheducation-2013.1.354 ◽

2013 ◽

Vol 2013 (1) ◽

pp. 354-361 ◽

Cited By ~ 31

Author(s):

Swee Lay Thein

Keyword(s):

Association Studies ◽

Globin Gene ◽

Genetic Association Studies ◽

Fetal Hemoglobin ◽

Clinical Severity ◽

Genetic Modifiers ◽

Genetic Studies ◽

Globin Gene Regulation ◽

Innate Ability

Abstract Characterization of the molecular basis of the β-thalassemias and sickle cell disease (SCD) clearly showed that individuals with the same β-globin genotypes can have extremely diverse clinical severity. Two key modifiers, an innate ability to produce fetal hemoglobin and coinheritance of α-thalassemia, both derived from family and population studies, affect the pathophysiology of both disorders at the primary level. In the past 2 decades, scientific research had applied genetic approaches to identify additional genetic modifiers. The review summarizes recent genetic studies and key genetic modifiers identified and traces the story of fetal hemoglobin genetics, which has led to an emerging network of globin gene regulation. The discoveries have provided insights on new targets for therapeutic intervention and raise possibilities of developing fetal hemoglobin predictive diagnostics for predicting disease severity in the newborn and for integration into prenatal diagnosis to better inform genetic counseling.

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Role of Lung Ultrasound in Predicting Clinical Severity and Fatality in COVID-19 Pneumonia

Journal of Personalized Medicine ◽

10.3390/jpm11080757 ◽

2021 ◽

Vol 11 (8) ◽

pp. 757

Author(s):

Ivan Skopljanac ◽

Mirela Pavicic Ivelja ◽

Ognjen Barcot ◽

Ivan Brdar ◽

Kresimir Dolic ◽

...

Keyword(s):

Hospital Admission ◽

Disease Severity ◽

Predictive Power ◽

Lung Ultrasound ◽

Clinical Severity ◽

Imaging Method ◽

High Flow Nasal Cannula ◽

Severity Of The Disease

Background: Lung ultrasound (LUS) is a useful imaging method for identifying COVID-19 pneumonia. The aim of this study was to explore the role of LUS in predicting the severity of the disease and fatality in patients with COVID-19. Methods: This was a single-center, follow-up study, conducted from 1 November 2020, to 22 March 2021. The LUS protocol was based on the assessment of 14 lung zones with a total score up to 42, which was compared to the disease severity and fatality. Results: A total of 133 patients with COVID-19 pneumonia confirmed by RT-PCR were enrolled, with a median time from hospital admission to lung ultrasound of one day. The LUS score was correlated with clinical severity at hospital admission (Spearman’s rho 0.40, 95% CI 0.24 to 0.53, p < 0.001). Patients with higher LUS scores were experiencing greater disease severity; a high flow nasal cannula had an odds ratio of 1.43 (5% CI 1.17–1.74) in patients with LUS score > 29; the same score also predicted the need for mechanical ventilation (1.25, [1.07–1.48]). An LUS score > 30 (1.41 [1.18–1.68]) and age over 68 (1.26 [1.11–1.43]) were significant predictors of fatality. Conclusions: LUS at hospital admission is shown to have a high predictive power of the severity and fatality of COVID-19 pneumonia.

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The Role of miRNAs as Therapeutic Tools in Sickle Cell Disease

Medicina ◽

10.3390/medicina57101106 ◽

2021 ◽

Vol 57 (10) ◽

pp. 1106

Author(s):

Cyril Cyrus

Keyword(s):

Sickle Cell ◽

Cell Cycle Progression ◽

Globin Gene ◽

Erythroid Differentiation ◽

Clinical Severity ◽

Functional Studies ◽

Abnormal Hemoglobin ◽

Therapeutic Tools ◽

Targeted Medicine

Background and Objectives: Sickle cell disorder (SCD) is a paradigmatic example of a complex monogenic disorder. SCD is characterized by the production of abnormal hemoglobin, primarily in the deoxygenated state, which makes erythrocytes susceptible to intracellular hemoglobin polymerization. Functional studies have affirmed that the dysregulation of miRNAs enhances clinical severity or has an ameliorating effect in SCD. miRNAs can be effectively regulated to reduce the pace of cell cycle progression, to reduce iron levels, to influence hemolysis and oxidative stress, and most importantly, to increase γ-globin gene expression and enhance the effectiveness of hydroxyurea. Results: This review highlights the roles played by some key miRNAs in hemoglobinopathies, especially in hematopoiesis, erythroid differentiation, and severity of anemia, which make miRNAs attractive molecular tools for innovative therapeutic approaches. Conclusion: In this era of targeted medicine, miRNAs mimics and antagomirs may be promising inducers of HbF synthesis which could ameliorate the clinical severity of SCD.

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Pathophysiology of COVID-19: Mechanisms Underlying Disease Severity and Progression

Physiology ◽

10.1152/physiol.00019.2020 ◽

2020 ◽

Vol 35 (5) ◽

pp. 288-301 ◽

Cited By ~ 5

Author(s):

Mary Kathryn Bohn ◽

Alexandra Hall ◽

Lusia Sepiashvili ◽

Benjamin Jung ◽

Shannon Steele ◽

...

Keyword(s):

Immune Response ◽

Organ Failure ◽

Disease Severity ◽

Viral Entry ◽

Wide Spectrum ◽

Underlying Disease ◽

Viral Clearance ◽

Clinical Severity ◽

Global Epidemiology

The global epidemiology of coronavirus disease 2019 (COVID-19) suggests a wide spectrum of clinical severity, ranging from asymptomatic to fatal. Although the clinical and laboratory characteristics of COVID-19 patients have been well characterized, the pathophysiological mechanisms underlying disease severity and progression remain unclear. This review highlights key mechanisms that have been proposed to contribute to COVID-19 progression from viral entry to multisystem organ failure, as well as the central role of the immune response in successful viral clearance or progression to death.

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