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Topriceanu CC, Pereira AC, Moon JC, Captur G, Ho CY. Meta-Analysis of Penetrance and Systematic Review on Transition to Disease in Genetic Hypertrophic Cardiomyopathy. Circulation 2024; 149:107-123. [PMID: 37929589 PMCID: PMC10775968 DOI: 10.1161/circulationaha.123.065987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Accepted: 10/27/2023] [Indexed: 11/07/2023]
Abstract
BACKGROUND Hypertrophic cardiomyopathy (HCM) is characterized by unexplained left ventricular hypertrophy and is classically caused by pathogenic or likely pathogenic variants (P/LP) in genes encoding sarcomere proteins. Not all subclinical variant carriers will manifest clinically overt disease because penetrance (proportion of sarcomere or sarcomere-related P/LP variant carriers who develop disease) is variable, age dependent, and not reliably predicted. METHODS A systematic search of the literature was performed. We used random-effects generalized linear mixed model meta-analyses to contrast the cross-sectional prevalence and penetrance of sarcomere or sarcomere-related genes in 2 different contexts: clinically-based studies on patients and families with HCM versus population or community-based studies. Longitudinal family/clinical studies were additionally analyzed to investigate the rate of phenotypic conversion from subclinical to overt HCM during follow-up. RESULTS In total, 455 full-text manuscripts and articles were assessed. In family/clinical studies, the prevalence of sarcomere variants in patients diagnosed with HCM was 34%. The penetrance across all genes in nonproband relatives carrying P/LP variants identified during cascade screening was 57% (95% CI, 52%-63%), and the mean age at HCM diagnosis was 38 years (95% CI, 36%-40%). Penetrance varied from ≈32% for MYL3 (myosin light chain 3) to ≈55% for MYBPC3 (myosin-binding protein C3), ≈60% for TNNT2 (troponin T2) and TNNI3 (troponin I3), and ≈65% for MYH7 (myosin heavy chain 7). Population-based genetic studies demonstrate that P/LP sarcomere variants are present in the background population but at a low prevalence of <1%. The penetrance of HCM in incidentally identified P/LP variant carriers was also substantially lower at ≈11%, ranging from 0% in Atherosclerosis Risk in Communities to 18% in UK Biobank. In longitudinal family studies, the pooled phenotypic conversion across all genes was 15% over an average of ≈8 years of follow-up, starting from a mean of ≈16 years of age. However, short-term gene-specific phenotypic conversion varied between ≈12% for MYBPC3 and ≈23% for MYH7. CONCLUSIONS The penetrance of P/LP variants is highly variable and influenced by currently undefined and context-dependent genetic and environmental factors. Additional longitudinal studies are needed to improve our understanding of true lifetime penetrance in families and in the community and to identify drivers of the transition from subclinical to overt HCM.
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Affiliation(s)
- Constantin-Cristian Topriceanu
- Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA (C.-C.T., A.C.P., C.Y.H.). UCL Institute of Cardiovascular Science (C.-C.T., J.C.M., G.C.) and UCL MRC Unit for Lifelong Health and Ageing (G.C.), University College London, UK. Cardiac MRI Unit, Barts Heart Centre, West Smithfield, London, UK (C.-C.T., J.C.M.). The Royal Free Hospital, Centre for Inherited Heart Muscle Conditions, Cardiology Department, Hampstead, London, UK (G.C.)
| | - Alexandre C. Pereira
- Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA (C.-C.T., A.C.P., C.Y.H.). UCL Institute of Cardiovascular Science (C.-C.T., J.C.M., G.C.) and UCL MRC Unit for Lifelong Health and Ageing (G.C.), University College London, UK. Cardiac MRI Unit, Barts Heart Centre, West Smithfield, London, UK (C.-C.T., J.C.M.). The Royal Free Hospital, Centre for Inherited Heart Muscle Conditions, Cardiology Department, Hampstead, London, UK (G.C.)
| | - James C. Moon
- Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA (C.-C.T., A.C.P., C.Y.H.). UCL Institute of Cardiovascular Science (C.-C.T., J.C.M., G.C.) and UCL MRC Unit for Lifelong Health and Ageing (G.C.), University College London, UK. Cardiac MRI Unit, Barts Heart Centre, West Smithfield, London, UK (C.-C.T., J.C.M.). The Royal Free Hospital, Centre for Inherited Heart Muscle Conditions, Cardiology Department, Hampstead, London, UK (G.C.)
| | - Gabriella Captur
- Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA (C.-C.T., A.C.P., C.Y.H.). UCL Institute of Cardiovascular Science (C.-C.T., J.C.M., G.C.) and UCL MRC Unit for Lifelong Health and Ageing (G.C.), University College London, UK. Cardiac MRI Unit, Barts Heart Centre, West Smithfield, London, UK (C.-C.T., J.C.M.). The Royal Free Hospital, Centre for Inherited Heart Muscle Conditions, Cardiology Department, Hampstead, London, UK (G.C.)
| | - Carolyn Y. Ho
- Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA (C.-C.T., A.C.P., C.Y.H.). UCL Institute of Cardiovascular Science (C.-C.T., J.C.M., G.C.) and UCL MRC Unit for Lifelong Health and Ageing (G.C.), University College London, UK. Cardiac MRI Unit, Barts Heart Centre, West Smithfield, London, UK (C.-C.T., J.C.M.). The Royal Free Hospital, Centre for Inherited Heart Muscle Conditions, Cardiology Department, Hampstead, London, UK (G.C.)
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Best LG, O’Leary M, O’Leary R, Lawrence W, Torgerson DG. Return of Participants' Incidental Genetic Research Findings: Experience from a Case-Control Study of Asthma in an American Indian Community. J Pers Med 2023; 13:1407. [PMID: 37763174 PMCID: PMC10532458 DOI: 10.3390/jpm13091407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Revised: 09/14/2023] [Accepted: 09/18/2023] [Indexed: 09/29/2023] Open
Abstract
The proper communication of clinically actionable findings to participants of genetic research entails important ethical considerations, but has been challenging for a variety of reasons. We document an instance of the return of individual genetic results in the context of a very rural American Indian community, in hopes of providing insight to other investigators about potentially superior or inferior courses of action. This was a case/control study of asthma among 324 pediatric participants. Subsequently, microarray genotype data became available, providing over 2 million variants, incidentally including some conferring risk for conditions for which the American College of Medical Genetics recommends return of results. The study investigators engaged in extensive consultation with the IRB, the tribal government, and local clinicians to better inform our approach. We were able to notify the two participants heterozygous for the one clinically actionable variant identified. One participant welcomed this information and proceeded to obtain further clinical work-up; the other participant declined further follow-up. While demanding considerable time and effort, the return of clinically actionable genetic results is important from both an ethical perspective and to provide an improved trust relationship with the community of research participants.
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Affiliation(s)
- Lyle G. Best
- School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND 58202, USA
- Missouri Breaks Industries Research Inc., Eagle Butte, SD 57625, USA; (M.O.); (R.O.); (W.L.)
| | - Marcia O’Leary
- Missouri Breaks Industries Research Inc., Eagle Butte, SD 57625, USA; (M.O.); (R.O.); (W.L.)
| | - Rae O’Leary
- Missouri Breaks Industries Research Inc., Eagle Butte, SD 57625, USA; (M.O.); (R.O.); (W.L.)
| | - Wendy Lawrence
- Missouri Breaks Industries Research Inc., Eagle Butte, SD 57625, USA; (M.O.); (R.O.); (W.L.)
| | - Dara G. Torgerson
- Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA 94158, USA;
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Best LG, O'Leary M, O'Leary R, Lawrence W, Torgerson DG. Return of Participants' Incidental Genetic Research Findings: Experience from a Case-Control Study of Asthma in an American Indian Community. RESEARCH SQUARE 2023:rs.3.rs-2485539. [PMID: 36711525 PMCID: PMC9882662 DOI: 10.21203/rs.3.rs-2485539/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
PURPOSE The proper communication of clinically actionable findings to participants of genetic research entails important ethical considerations, but has been challenging for a variety of reasons. We document an instance of return of individual genetic results in the context of a very rural American Indian community, in hopes of providing insight to other investigators about potentially superior or inferior courses of action. METHODS The original study was a case/control study of asthma among 324 pediatric participants. The study utilized a genotyping microarray assessing over 2 million variants, including one conferring risk for hypertrophic cardiomyopathy for which the American College of Medical Genetics recommends return of results to participants. The study investigators engaged in extensive consultation with the IRB, the Tribal government and local clinicians to better inform our approach. RESULTS With some difficulty we were able to notify the 2 participants heterozygous for this variant. One participant welcomed this information and proceeded to obtain further clinical work-up; the other participant declined further follow-up. CONCLUSION While demanding of considerable time and effort, the return of clinically actionable genetic results is important from both an ethical perspective and to provide an improved trust relationship with the community of research participants.
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Affiliation(s)
| | | | - Rae O'Leary
- Missouri Breaks Industries Research Inc, Eagle Butte
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Kucher AN, Valiakhmetov NR, Salakhov RR, Golubenko MV, Pavlyukova EN, Nazarenko MS. Phenotype variation of hypertrophic cardiomyopathy in carriers of the p.Arg870His pathogenic variant in the MYH7 gene. BULLETIN OF SIBERIAN MEDICINE 2022. [DOI: 10.20538/1682-0363-2022-3-205-216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The review analyzes variability of clinical manifestations of p.Arg870His in the MYH7 gene, which is repeatedly registered in patients with hypertrophic cardiomyopathy (HCM). The analysis involves the data from scientific publications obtained as a search result in the PubMed, СlinVar, and eLibrary.ru databases, as well as authors’ own results. A wide range of phenotypic manifestations have been revealed in carriers of p.Arg870His, from the asymptomatic to severe course, rapid progression, and early death. The review considers possible factors that modify the effect of the pathogenic variant (i.e. dosage of the pathogenic variant, the presence of other unfavorable genetic variants, etc.). The importance of accumulating information on the clinical features of HCM in the carriers of specific gene variants is emphasized in order to clarify their pathogenicity and to identify factors modifying the clinical outcome, which is important for the choice of the treatment strategy for HCM.
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Affiliation(s)
- A. N. Kucher
- Research Institute of Medical Genetics, Tomsk National Research Medical Center (NRMC), Russian Academy of Sciences
| | - N. R. Valiakhmetov
- Research Institute of Medical Genetics, Tomsk National Research Medical Center (NRMC), Russian Academy of Sciences
| | - R. R. Salakhov
- Research Institute of Medical Genetics, Tomsk National Research Medical Center (NRMC), Russian Academy of Sciences; Siberian State Medical University
| | - M. V. Golubenko
- Research Institute of Medical Genetics, Tomsk National Research Medical Center (NRMC), Russian Academy of Sciences
| | - E. N. Pavlyukova
- Cardiology Research Institute, Tomsk National Research Medical Center (NRMC), Russian Academy of Sciences
| | - M. S. Nazarenko
- Research Institute of Medical Genetics, Tomsk National Research Medical Center (NRMC), Russian Academy of Sciences; Siberian State Medical University
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Rani DS, Vijaya Kumar A, Nallari P, Sampathkumar K, Dhandapany PS, Narasimhan C, Rathinavel A, Thangaraj K. Novel Mutations in β-MYH7 Gene in Indian Patients With Dilated Cardiomyopathy. CJC Open 2022; 4:1-11. [PMID: 35072022 PMCID: PMC8767027 DOI: 10.1016/j.cjco.2021.07.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 07/30/2021] [Indexed: 11/29/2022] Open
Abstract
Background Methods Results Conclusions
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Affiliation(s)
- Deepa Selvi Rani
- Council of Scientific and Industrial Research-Centre for Cellular and Molecular Biology, Hyderabad, India
- Corresponding authors: Drs Deepa Selvi Rani and Kumarasamy Thangaraj, CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India. Tel.: +91-40-27192637.
| | - Archana Vijaya Kumar
- Council of Scientific and Industrial Research-Centre for Cellular and Molecular Biology, Hyderabad, India
- Department of Pathology and Immunology, University of Geneva Hospital, Geneva, Switzerland
| | | | - Katakam Sampathkumar
- Council of Scientific and Industrial Research-Centre for Cellular and Molecular Biology, Hyderabad, India
| | | | | | - Andiappan Rathinavel
- Department of Cardio-Thoracic Surgery, Government Rajaji Hospital, Madurai, India
| | - Kumarasamy Thangaraj
- Council of Scientific and Industrial Research-Centre for Cellular and Molecular Biology, Hyderabad, India
- Department of Biotechnology-Centre for DNA Fingerprinting and Diagnostics, Hyderabad, Telangana, India
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Singh RR, McNamara JW, Sadayappan S. Mutations in myosin S2 alter cardiac myosin-binding protein-C interaction in hypertrophic cardiomyopathy in a phosphorylation-dependent manner. J Biol Chem 2021; 297:100836. [PMID: 34051236 PMCID: PMC8239744 DOI: 10.1016/j.jbc.2021.100836] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 05/18/2021] [Accepted: 05/25/2021] [Indexed: 12/31/2022] Open
Abstract
Hypertrophic cardiomyopathy (HCM) is an inherited cardiovascular disorder primarily caused by mutations in the β-myosin heavy-chain gene. The proximal subfragment 2 region (S2), 126 amino acids of myosin, binds with the C0-C2 region of cardiac myosin-binding protein-C to regulate cardiac muscle contractility in a manner dependent on PKA-mediated phosphorylation. However, it is unknown if HCM-associated mutations within S2 dysregulate actomyosin dynamics by disrupting its interaction with C0-C2, ultimately leading to HCM. Herein, we study three S2 mutations known to cause HCM: R870H, E924K, and E930Δ. First, experiments using recombinant proteins, solid-phase binding, and isothermal titrating calorimetry assays independently revealed that mutant S2 proteins displayed significantly reduced binding with C0-C2. In addition, CD revealed greater instability of the coiled-coil structure in mutant S2 proteins compared with S2Wt proteins. Second, mutant S2 exhibited 5-fold greater affinity for PKA-treated C0-C2 proteins. Third, skinned papillary muscle fibers treated with mutant S2 proteins showed no change in the rate of force redevelopment as a measure of actin–myosin cross-bridge kinetics, whereas S2Wt showed increased the rate of force redevelopment. In summary, S2 and C0-C2 interaction mediated by phosphorylation is altered by mutations in S2, which augment the speed and force of contraction observed in HCM. Modulating this interaction could be a potential strategy to treat HCM in the future.
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Affiliation(s)
- Rohit R Singh
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, Heart, Lung and Vascular Institute, University of Cincinnati, Cincinnati, Ohio, USA
| | - James W McNamara
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, Heart, Lung and Vascular Institute, University of Cincinnati, Cincinnati, Ohio, USA
| | - Sakthivel Sadayappan
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, Heart, Lung and Vascular Institute, University of Cincinnati, Cincinnati, Ohio, USA.
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Schuldt M, Johnston JR, He H, Huurman R, Pei J, Harakalova M, Poggesi C, Michels M, Kuster DWD, Pinto JR, van der Velden J. Mutation location of HCM-causing troponin T mutations defines the degree of myofilament dysfunction in human cardiomyocytes. J Mol Cell Cardiol 2021; 150:77-90. [PMID: 33148509 PMCID: PMC10616699 DOI: 10.1016/j.yjmcc.2020.10.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 10/03/2020] [Accepted: 10/13/2020] [Indexed: 01/25/2023]
Abstract
BACKGROUND The clinical outcome of hypertrophic cardiomyopathy patients is not only determined by the disease-causing mutation but influenced by a variety of disease modifiers. Here, we defined the role of the mutation location and the mutant protein dose of the troponin T mutations I79N, R94C and R278C. METHODS AND RESULTS We determined myofilament function after troponin exchange in permeabilized single human cardiomyocytes as well as in cardiac patient samples harboring the R278C mutation. Notably, we found that a small dose of mutant protein is sufficient for the maximal effect on myofilament Ca2+-sensitivity for the I79N and R94C mutation while the mutation location determines the magnitude of this effect. While incorporation of I79N and R94C increased myofilament Ca2+-sensitivity, incorporation of R278C increased Ca2+-sensitivity at low and intermediate dose, while it decreased Ca2+-sensitivity at high dose. All three cTnT mutants showed reduced thin filament binding affinity, which coincided with a relatively low maximal exchange (50.5 ± 5.2%) of mutant troponin complex in cardiomyocytes. In accordance, 32.2 ± 4.0% mutant R278C was found in two patient samples which showed 50.0 ± 3.7% mutant mRNA. In accordance with studies that showed clinical variability in patients with the exact same mutation, we observed variability on the functional single cell level in patients with the R278C mutation. These differences in myofilament properties could not be explained by differences in the amount of mutant protein. CONCLUSIONS Using troponin exchange in single human cardiomyocytes, we show that TNNT2 mutation-induced changes in myofilament Ca2+-sensitivity depend on mutation location, while all mutants show reduced thin filament binding affinity. The specific mutation-effect observed for R278C could not be translated to myofilament function of cardiomyocytes from patients, and is most likely explained by other (post)-translational troponin modifications. Overall, our studies illustrate that mutation location underlies variability in myofilament Ca2+-sensitivity, while only the R278C mutation shows a highly dose-dependent effect on myofilament function.
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Affiliation(s)
- Maike Schuldt
- Amsterdam UMC, Vrije Universiteit Amsterdam, Department of Physiology, Amsterdam Cardiovascular Sciences, Amsterdam, The Netherlands.
| | - Jamie R Johnston
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL, USA
| | - Huan He
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL, USA; Institute of Molecular Biophysics, Florida State University, Tallahassee, FL, USA
| | - Roy Huurman
- Department of Cardiology, Thorax Center, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Jiayi Pei
- Department of Cardiology, Division Heart and Lungs, University Medical Center Utrecht, Utrecht, The Netherlands; Regenerative Medicine Utrecht, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Magdalena Harakalova
- Department of Cardiology, Division Heart and Lungs, University Medical Center Utrecht, Utrecht, The Netherlands; Regenerative Medicine Utrecht, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Corrado Poggesi
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Michelle Michels
- Department of Cardiology, Thorax Center, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Diederik W D Kuster
- Amsterdam UMC, Vrije Universiteit Amsterdam, Department of Physiology, Amsterdam Cardiovascular Sciences, Amsterdam, The Netherlands
| | - Jose R Pinto
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL, USA
| | - Jolanda van der Velden
- Amsterdam UMC, Vrije Universiteit Amsterdam, Department of Physiology, Amsterdam Cardiovascular Sciences, Amsterdam, The Netherlands
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Du Y, Wang Y, Han X, Feng Z, Ma A. MYH7 Gene-Related Mutation p.V878L Identified in a Chinese Family with Hypertrophic Cardiomyopathy. Int Heart J 2019; 60:1415-1420. [PMID: 31735781 DOI: 10.1536/ihj.19-146] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Hypertrophic cardiomyopathy (HCM) is one of the most common inherited cardiovascular diseases and possesses a high risk for sudden cardiac death. Although mutations in more than 20 genes have been reported to be associated with HCM thus far, the genetic backgrounds of most HCM patients are not fully understood. We performed a genetic analysis in a Chinese family that presented with HCM using next-generation sequencing (NGS). Clinical data, family histories, and blood samples were collected from the proband and family members. Five patients showed typical clinical symptoms of HCM. One subject was the victim of sudden cardiac death. By NGS, we determined that these subjects with HCM symptoms carried a missense heterozygous genetic mutation c.2632C>A (p.V878L) in the myosin heavy chain 7 (MYH7) gene with an autosomal dominant pattern of inheritance. Individuals without this mutation showed no symptoms or cardiac structural abnormalities related to HCM. Bioinformatics evaluation predicted this mutant as "damaging" and "disease causing". Additionally, sequence alignment showed that this mutant is located in an evolutionarily conserved region of MYH7 in multiple species. Our results describe a potentially pathogenic mutation associated with HCM, which may extend the spectrum of HCM phenotypes related to MYH7 gene mutations.
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Affiliation(s)
- Yuan Du
- Department of Cardiovascular Medicine, First Affiliated Hospital of Xi'an Jiaotong University
| | - Ya Wang
- Department of Cardiovascular Medicine, First Affiliated Hospital of Xi'an Jiaotong University
| | - Xiu Han
- Department of Cardiovascular Medicine, First Affiliated Hospital of Xi'an Jiaotong University
| | - Zhanbin Feng
- Department of Cardiovascular Medicine, Ninth Hospital of Xi'an
| | - Aiqun Ma
- Department of Cardiovascular Medicine, First Affiliated Hospital of Xi'an Jiaotong University.,Shaanxi Key Laboratory of Molecular Cardiology, Xi'an Jiaotong University.,Key Laboratory of Environment and Genes Related to Diseases, Xi'an Jiaotong University, Ministry of Education
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Kraker J, Viswanathan SK, Knöll R, Sadayappan S. Recent Advances in the Molecular Genetics of Familial Hypertrophic Cardiomyopathy in South Asian Descendants. Front Physiol 2016; 7:499. [PMID: 27840609 PMCID: PMC5083855 DOI: 10.3389/fphys.2016.00499] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 10/12/2016] [Indexed: 12/14/2022] Open
Abstract
The South Asian population, numbered at 1.8 billion, is estimated to comprise around 20% of the global population and 1% of the American population, and has one of the highest rates of cardiovascular disease. While South Asians show increased classical risk factors for developing heart failure, the role of population-specific genetic risk factors has not yet been examined for this group. Hypertrophic cardiomyopathy (HCM) is one of the major cardiac genetic disorders among South Asians, leading to contractile dysfunction, heart failure, and sudden cardiac death. This disease displays autosomal dominant inheritance, and it is associated with a large number of variants in both sarcomeric and non-sarcomeric proteins. The South Asians, a population with large ethnic diversity, potentially carries region-specific polymorphisms. There is high variability in disease penetrance and phenotypic expression of variants associated with HCM. Thus, extensive studies are required to decipher pathogenicity and the physiological mechanisms of these variants, as well as the contribution of modifier genes and environmental factors to disease phenotypes. Conducting genotype-phenotype correlation studies will lead to improved understanding of HCM and, consequently, improved treatment options for this high-risk population. The objective of this review is to report the history of cardiovascular disease and HCM in South Asians, present previously published pathogenic variants, and introduce current efforts to study HCM using induced pluripotent stem cell-derived cardiomyocytes, next-generation sequencing, and gene editing technologies. The authors ultimately hope that this review will stimulate further research, drive novel discoveries, and contribute to the development of personalized medicine with the aim of expanding therapeutic strategies for HCM.
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Affiliation(s)
- Jessica Kraker
- Department of Internal Medicine, Heart, Lung and Vascular Institute, Division of Cardiovascular Health and Sciences, University of Cincinnati College of Medicine Cincinnati, OH, USA
| | - Shiv Kumar Viswanathan
- Department of Internal Medicine, Heart, Lung and Vascular Institute, Division of Cardiovascular Health and Sciences, University of Cincinnati College of Medicine Cincinnati, OH, USA
| | - Ralph Knöll
- AstraZeneca R&D Mölndal, Innovative Medicines and Early Development, Cardiovascular and Metabolic Diseases iMedMölndal, Sweden; Integrated Cardio Metabolic Centre, Karolinska Institutet, Myocardial Genetics, Karolinska University Hospital in HuddingeHuddinge, Sweden
| | - Sakthivel Sadayappan
- Department of Internal Medicine, Heart, Lung and Vascular Institute, Division of Cardiovascular Health and Sciences, University of Cincinnati College of Medicine Cincinnati, OH, USA
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The sarcomeric M-region: a molecular command center for diverse cellular processes. BIOMED RESEARCH INTERNATIONAL 2015; 2015:714197. [PMID: 25961035 PMCID: PMC4413555 DOI: 10.1155/2015/714197] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 02/08/2015] [Indexed: 02/07/2023]
Abstract
The sarcomeric M-region anchors thick filaments and withstands the mechanical stress of contractions by deformation, thus enabling distribution of physiological forces along the length of thick filaments. While the role of the M-region in supporting myofibrillar structure and contractility is well established, its role in mediating additional cellular processes has only recently started to emerge. As such, M-region is the hub of key protein players contributing to cytoskeletal remodeling, signal transduction, mechanosensing, metabolism, and proteasomal degradation. Mutations in genes encoding M-region related proteins lead to development of severe and lethal cardiac and skeletal myopathies affecting mankind. Herein, we describe the main cellular processes taking place at the M-region, other than thick filament assembly, and discuss human myopathies associated with mutant or truncated M-region proteins.
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Tanjore R, Rangaraju A, Vadapalli S, Remersu S, Narsimhan C, Nallari P. Genetic variations of β-MYH7 in hypertrophic cardiomyopathy and dilated cardiomyopathy. INDIAN JOURNAL OF HUMAN GENETICS 2011; 16:67-71. [PMID: 21031054 PMCID: PMC2955954 DOI: 10.4103/0971-6866.69348] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
CONTEXT: Hypertrophic cardiomyopathy (HCM) is known to be manifested by mutations in 12 sarcomeric genes and dilated cardiomyopathy (DCM) is known to manifest due to cytoskeletal mutations. Studies have revealed that sarcomeric mutations can also lead to DCM. Therefore, in the present study, we have made an attempt to compare and analyze the genetic variations of beta-myosin heavy chain gene (β-MYH7), which are interestingly found to be common in both HCM and DCM. The underlying pathophysiological mechanism leading to two different phenotypes has been discussed in this study. Till date, about 186 and 73 different mutations have been reported in HCM and DCM, respectively, with respect to this gene. AIM: The screening of β-MYH7 gene in both HCM and DCM has revealed some common genetic variations. The aim of the present study is to understand the pathophysiological mechanism underlying the manifestation of two different phenotypes. MATERIALS AND METHODS: 100 controls, 95 HCM and 97 DCM samples were collected. Genomic DNA was extracted following rapid nonenzymatic method as described by Lahiri and Nurnberger (1991), and the extracted DNA was later subjected to polymerase chain reaction (PCR) based single stranded conformation polymorphism (SSCP) analysis to identify single nucleotide polymorphism (SNP)s/mutations associated with the diseased phenotypes. RESULTS AND CONCLUSION: Similar variations were observed in β-MYH7 exons 7, 12, 19 and 20 in both HCM and DCM. This could be attributed to impaired energy compromise, or to dose effect of the mutant protein, or to even environmental factors/modifier gene effects wherein an HCM could progress to a DCM phenotype affecting both right and left ventricles, leading to heart failure.
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Affiliation(s)
- Reena Tanjore
- Department of Genetics, Osmania University, Jamai Osmania P.O., Hyderabad-500 007, India
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Genotype phenotype correlations of cardiac beta-myosin heavy chain mutations in Indian patients with hypertrophic and dilated cardiomyopathy. Mol Cell Biochem 2008; 321:189-96. [PMID: 18953637 DOI: 10.1007/s11010-008-9932-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2008] [Accepted: 10/13/2008] [Indexed: 10/21/2022]
Abstract
The aim of the current study was to determine the frequency of mutations in the beta-myosin heavy chain gene (MYH7) in a cohort of hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM) and their families, and to investigate correlations between genotype and phenotype. About 130 consecutive patients diagnosed with HCM or DCM (69 with HCM and 61 with DCM) attending the cardiology clinic of Post Graduate Institute of Medical Education and Research were screened for mutations in the MYH7 gene. The control group for genetic studies consisted of 100 healthy subjects. We report 14 mutations in 6 probands (5 probands in HCM and 1 proband in DCM) and their family members. Out of these 6 mutations, 3 are new and are being reported for the first time. One known mutation (p.Gly716Arg) was found to be "de novo" which resulted in severe asymmetric septal hypertrophy (31 mm) and resulted in the sudden cardiac death (SCD) of the proband at the age of 21 years. Further, a DCM causing novel mutation p.Gly377Ser was identified which resulted in the milder phenotype. The present study shows that there is genetic and phenotypic heterogeneity of cardiomyopathies in Indian population. Further, the location and type of mutation in a given sarcomeric gene determines the severity and phenotypic plasticity in cardiomyopathies.
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