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Lee S, Vander Roest AS, Blair CA, Kao K, Bremner SB, Childers MC, Pathak D, Heinrich P, Lee D, Chirikian O, Mohran SE, Roberts B, Smith JE, Jahng JW, Paik DT, Wu JC, Gunawardane RN, Ruppel KM, Mack DL, Pruitt BL, Regnier M, Wu SM, Spudich JA, Bernstein D. Incomplete-penetrant hypertrophic cardiomyopathy MYH7 G256E mutation causes hypercontractility and elevated mitochondrial respiration. Proc Natl Acad Sci U S A 2024; 121:e2318413121. [PMID: 38683993 PMCID: PMC11087781 DOI: 10.1073/pnas.2318413121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2023] [Accepted: 03/05/2024] [Indexed: 05/02/2024] Open
Abstract
Determining the pathogenicity of hypertrophic cardiomyopathy-associated mutations in the β-myosin heavy chain (MYH7) can be challenging due to its variable penetrance and clinical severity. This study investigates the early pathogenic effects of the incomplete-penetrant MYH7 G256E mutation on myosin function that may trigger pathogenic adaptations and hypertrophy. We hypothesized that the G256E mutation would alter myosin biomechanical function, leading to changes in cellular functions. We developed a collaborative pipeline to characterize myosin function across protein, myofibril, cell, and tissue levels to determine the multiscale effects on structure-function of the contractile apparatus and its implications for gene regulation and metabolic state. The G256E mutation disrupts the transducer region of the S1 head and reduces the fraction of myosin in the folded-back state by 33%, resulting in more myosin heads available for contraction. Myofibrils from gene-edited MYH7WT/G256E human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) exhibited greater and faster tension development. This hypercontractile phenotype persisted in single-cell hiPSC-CMs and engineered heart tissues. We demonstrated consistent hypercontractile myosin function as a primary consequence of the MYH7 G256E mutation across scales, highlighting the pathogenicity of this gene variant. Single-cell transcriptomic and metabolic profiling demonstrated upregulated mitochondrial genes and increased mitochondrial respiration, indicating early bioenergetic alterations. This work highlights the benefit of our multiscale platform to systematically evaluate the pathogenicity of gene variants at the protein and contractile organelle level and their early consequences on cellular and tissue function. We believe this platform can help elucidate the genotype-phenotype relationships underlying other genetic cardiovascular diseases.
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Affiliation(s)
- Soah Lee
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA94305
- Department of Biopharmaceutical Convergence, Sungkyunkwan University School of Pharmacy, Suwon, Gyeonggi-do16419South Korea
- School of Pharmacy, Sungkyunkwan University School of Pharmacy, Suwon, Gyeonggi-do16419, South Korea
| | - Alison S. Vander Roest
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Stanford, CA94305
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI48109
| | - Cheavar A. Blair
- Biological Engineering, University of California, Santa Barbara, CA93106
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY40536
| | - Kerry Kao
- Department of Bioengineering, University of Washington School of Medicine and College of Engineering, Seattle, WA98195
| | - Samantha B. Bremner
- Department of Bioengineering, University of Washington School of Medicine and College of Engineering, Seattle, WA98195
| | - Matthew C. Childers
- Department of Bioengineering, University of Washington School of Medicine and College of Engineering, Seattle, WA98195
| | - Divya Pathak
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA94305
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA94305
| | - Paul Heinrich
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA94305
| | - Daniel Lee
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA94305
| | - Orlando Chirikian
- Biological Engineering, University of California, Santa Barbara, CA93106
| | - Saffie E. Mohran
- Department of Bioengineering, University of Washington School of Medicine and College of Engineering, Seattle, WA98195
| | | | | | - James W. Jahng
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA94305
| | - David T. Paik
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA94305
| | - Joseph C. Wu
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA94305
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, CA94305
| | | | - Kathleen M. Ruppel
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA94305
| | - David L. Mack
- Department of Bioengineering, University of Washington School of Medicine and College of Engineering, Seattle, WA98195
| | - Beth L. Pruitt
- Biological Engineering, University of California, Santa Barbara, CA93106
| | - Michael Regnier
- Department of Bioengineering, University of Washington School of Medicine and College of Engineering, Seattle, WA98195
| | - Sean M. Wu
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA94305
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, CA94305
| | - James A. Spudich
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA94305
| | - Daniel Bernstein
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA94305
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Stanford, CA94305
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Arbelo E, Protonotarios A, Gimeno JR, Arbustini E, Barriales-Villa R, Basso C, Bezzina CR, Biagini E, Blom NA, de Boer RA, De Winter T, Elliott PM, Flather M, Garcia-Pavia P, Haugaa KH, Ingles J, Jurcut RO, Klaassen S, Limongelli G, Loeys B, Mogensen J, Olivotto I, Pantazis A, Sharma S, Van Tintelen JP, Ware JS, Kaski JP. 2023 ESC Guidelines for the management of cardiomyopathies. Eur Heart J 2023; 44:3503-3626. [PMID: 37622657 DOI: 10.1093/eurheartj/ehad194] [Citation(s) in RCA: 318] [Impact Index Per Article: 318.0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 08/26/2023] Open
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3
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Lee S, Roest ASV, Blair CA, Kao K, Bremner SB, Childers MC, Pathak D, Heinrich P, Lee D, Chirikian O, Mohran S, Roberts B, Smith JE, Jahng JW, Paik DT, Wu JC, Gunawardane RN, Spudich JA, Ruppel K, Mack D, Pruitt BL, Regnier M, Wu SM, Bernstein D. Multi-scale models reveal hypertrophic cardiomyopathy MYH7 G256E mutation drives hypercontractility and elevated mitochondrial respiration. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.08.544276. [PMID: 37333118 PMCID: PMC10274883 DOI: 10.1101/2023.06.08.544276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Rationale Over 200 mutations in the sarcomeric protein β-myosin heavy chain (MYH7) have been linked to hypertrophic cardiomyopathy (HCM). However, different mutations in MYH7 lead to variable penetrance and clinical severity, and alter myosin function to varying degrees, making it difficult to determine genotype-phenotype relationships, especially when caused by rare gene variants such as the G256E mutation. Objective This study aims to determine the effects of low penetrant MYH7 G256E mutation on myosin function. We hypothesize that the G256E mutation would alter myosin function, precipitating compensatory responses in cellular functions. Methods We developed a collaborative pipeline to characterize myosin function at multiple scales (protein to myofibril to cell to tissue). We also used our previously published data on other mutations to compare the degree to which myosin function was altered. Results At the protein level, the G256E mutation disrupts the transducer region of the S1 head and reduces the fraction of myosin in the folded-back state by 50.9%, suggesting more myosins available for contraction. Myofibrils isolated from hiPSC-CMs CRISPR-edited with G256E (MYH7 WT/G256E ) generated greater tension, had faster tension development and slower early phase relaxation, suggesting altered myosin-actin crossbridge cycling kinetics. This hypercontractile phenotype persisted in single-cell hiPSC-CMs and engineered heart tissues. Single-cell transcriptomic and metabolic profiling demonstrated upregulation of mitochondrial genes and increased mitochondrial respiration, suggesting altered bioenergetics as an early feature of HCM. Conclusions MYH7 G256E mutation causes structural instability in the transducer region, leading to hypercontractility across scales, perhaps from increased myosin recruitment and altered crossbridge cycling. Hypercontractile function of the mutant myosin was accompanied by increased mitochondrial respiration, while cellular hypertrophy was modest in the physiological stiffness environment. We believe that this multi-scale platform will be useful to elucidate genotype-phenotype relationships underlying other genetic cardiovascular diseases.
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Chai AC, Cui M, Chemello F, Li H, Chen K, Tan W, Atmanli A, McAnally JR, Zhang Y, Xu L, Liu N, Bassel-Duby R, Olson EN. Base editing correction of hypertrophic cardiomyopathy in human cardiomyocytes and humanized mice. Nat Med 2023; 29:401-411. [PMID: 36797478 PMCID: PMC10053064 DOI: 10.1038/s41591-022-02176-5] [Citation(s) in RCA: 49] [Impact Index Per Article: 49.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 12/07/2022] [Indexed: 02/18/2023]
Abstract
The most common form of genetic heart disease is hypertrophic cardiomyopathy (HCM), which is caused by variants in cardiac sarcomeric genes and leads to abnormal heart muscle thickening. Complications of HCM include heart failure, arrhythmia and sudden cardiac death. The dominant-negative c.1208G>A (p.R403Q) pathogenic variant (PV) in β-myosin (MYH7) is a common and well-studied PV that leads to increased cardiac contractility and HCM onset. In this study we identify an adenine base editor and single-guide RNA system that can efficiently correct this human PV with minimal bystander editing and off-target editing at selected sites. We show that delivery of base editing components rescues pathological manifestations of HCM in induced pluripotent stem cell cardiomyocytes derived from patients with HCM and in a humanized mouse model of HCM. Our findings demonstrate the potential of base editing to treat inherited cardiac diseases and prompt the further development of adenine base editor-based therapies to correct monogenic variants causing cardiac disease.
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Affiliation(s)
- Andreas C Chai
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Miao Cui
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Francesco Chemello
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Hui Li
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Kenian Chen
- Quantitative Biomedical Research Center, Department of Population and Data Sciences, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Wei Tan
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Ayhan Atmanli
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - John R McAnally
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Yu Zhang
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Lin Xu
- Quantitative Biomedical Research Center, Department of Population and Data Sciences, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Ning Liu
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Rhonda Bassel-Duby
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Eric N Olson
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA.
- Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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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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Pollmann K, Kaltenecker E, Schleihauf J, Ewert P, Görlach A, Wolf CM. Compound Mutation in Cardiac Sarcomere Proteins Is Associated with Increased Risk for Major Arrhythmic Events in Pediatric Onset Hypertrophic Cardiomyopathy. J Clin Med 2021; 10:jcm10225256. [PMID: 34830538 PMCID: PMC8617951 DOI: 10.3390/jcm10225256] [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: 10/15/2021] [Revised: 11/02/2021] [Accepted: 11/09/2021] [Indexed: 12/14/2022] Open
Abstract
Hypertrophic cardiomyopathy (HCM) is associated with adverse left ventricular (LV) remodeling causing dysfunction and malignant arrhythmias. Severely affected patients present with disease onset during childhood and sudden cardiac death risk (SCD) stratification is of the highest importance in this cohort. This study aimed to investigate genotype–phenotype association regarding clinical outcome and disease progression in pediatric onset HCM. Medical charts from forty-nine patients with pediatric HCM who had undergone genetic testing were reviewed for retrospective analysis. Demographic, clinical, transthoracic echocardiographic, electrocardiographic, long-term electrocardiogram, cardiopulmonary exercise test, cardiac magnetic resonance, and medication data were recorded. Childhood onset HCM was diagnosed in 29 males and 20 females. Median age at last follow-up was 18.7 years (range 2.6–51.7 years) with a median follow-up time since diagnosis of 8.5 years (range 0.2–38.0 years). Comparison of patients carrying mutations in distinct genes and comparison of genotype-negative with genotype-positive individuals, revealed no differences in functional classification, LV morphology, hypertrophy, systolic and diastolic function, fibrosis and cardiac medication. Patients with compound mutations had a significantly higher risk for major arrhythmic events than a single-mutation carrier. No association between affected genes and disease severity or progression was identified in this cohort.
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Affiliation(s)
- Kathrin Pollmann
- German Heart Center Munich, Department of Congenital Heart Disease and Pediatric Cardiology, School of Medicine & Health, Technical University of Munich, 80636 Munich, Germany; (K.P.); (E.K.); (J.S.); (P.E.); (A.G.)
| | - Emanuel Kaltenecker
- German Heart Center Munich, Department of Congenital Heart Disease and Pediatric Cardiology, School of Medicine & Health, Technical University of Munich, 80636 Munich, Germany; (K.P.); (E.K.); (J.S.); (P.E.); (A.G.)
| | - Julia Schleihauf
- German Heart Center Munich, Department of Congenital Heart Disease and Pediatric Cardiology, School of Medicine & Health, Technical University of Munich, 80636 Munich, Germany; (K.P.); (E.K.); (J.S.); (P.E.); (A.G.)
| | - Peter Ewert
- German Heart Center Munich, Department of Congenital Heart Disease and Pediatric Cardiology, School of Medicine & Health, Technical University of Munich, 80636 Munich, Germany; (K.P.); (E.K.); (J.S.); (P.E.); (A.G.)
- DZHK (German Centre for Cardiovascular Research), Partner Site Munich Heart Alliance, 80802 Munich, Germany
| | - Agnes Görlach
- German Heart Center Munich, Department of Congenital Heart Disease and Pediatric Cardiology, School of Medicine & Health, Technical University of Munich, 80636 Munich, Germany; (K.P.); (E.K.); (J.S.); (P.E.); (A.G.)
- DZHK (German Centre for Cardiovascular Research), Partner Site Munich Heart Alliance, 80802 Munich, Germany
- Experimental and Molecular Pediatric Cardiology, Technical University of Munich, 80636 Munich, Germany
| | - Cordula M. Wolf
- German Heart Center Munich, Department of Congenital Heart Disease and Pediatric Cardiology, School of Medicine & Health, Technical University of Munich, 80636 Munich, Germany; (K.P.); (E.K.); (J.S.); (P.E.); (A.G.)
- DZHK (German Centre for Cardiovascular Research), Partner Site Munich Heart Alliance, 80802 Munich, Germany
- Correspondence:
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Abstract
In the absence of contemporary, population-based epidemiological studies, estimates of the incidence and prevalence of the inherited cardiomyopathies have been derived from screening studies, most often of young adult populations, to assess cardiovascular risk or to detect the presence of disease in athletes or military recruits. The global estimates for hypertrophic cardiomyopathy (1/500 individuals), dilated cardiomyopathy (1/250) and arrhythmogenic right ventricular cardiomyopathy (1/5,000) are probably conservative given that only individuals who fulfil diagnostic criteria would have been included. This caveat is highly relevant because a substantial minority or even a majority of individuals who carry disease-causing genetic variants and are at risk of disease complications have incomplete and/or late-onset disease expression. The genetic literature on cardiomyopathy, which is often focused on the identification of genetic variants, has been biased in favour of pedigrees with higher penetrance. In clinical practice, an abnormal electrocardiogram with normal or non-diagnostic imaging results is a common finding for the sarcomere variants that cause hypertrophic cardiomyopathy, the titin and sarcomere variants that cause dilated cardiomyopathy and the desmosomal variants that cause either arrhythmogenic right ventricular cardiomyopathy or dilated cardiomyopathy. Therefore, defining the genetic epidemiology is also challenging given the overlapping phenotypes, incomplete and age-related expression, and highly variable penetrance even within individual families carrying the same genetic variant.
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Affiliation(s)
- William J McKenna
- Institute of Cardiovascular Science, University College London, London, UK. .,Heart Hospital, Hamad Medical Corporation, Doha, Qatar.
| | - Daniel P Judge
- Section of Advanced HF & Transplant Cardiology, Medical University of South Carolina, Charleston, SC, USA
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Farrell E, Armstrong AE, Grimes AC, Naya FJ, de Lange WJ, Ralphe JC. Transcriptome Analysis of Cardiac Hypertrophic Growth in MYBPC3-Null Mice Suggests Early Responders in Hypertrophic Remodeling. Front Physiol 2018; 9:1442. [PMID: 30410445 PMCID: PMC6210548 DOI: 10.3389/fphys.2018.01442] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2018] [Accepted: 09/21/2018] [Indexed: 12/13/2022] Open
Abstract
Rationale: With a prevalence of 1 in 200 individuals, hypertrophic cardiomyopathy (HCM) is thought to be the most common genetic cardiac disease, with potential outcomes that include severe hypertrophy, heart failure, and sudden cardiac death (SCD). Though much research has furthered our understanding of how HCM-causing mutations in genes such as cardiac myosin-binding protein C (MYBPC3) impair contractile function, it remains unclear how such dysfunction leads to hypertrophy and/or arrhythmias, which comprise the HCM phenotype. Identification of early response mediators could provide rational therapeutic targets to reduce disease severity. Our goal was to differentiate physiologic and pathophysiologic hypertrophic growth responses and identify early genetic mediators in the development of cardiomegaly in the cardiac myosin-binding protein C-null (cMyBP-C-/-) mouse model of HCM. Methods and Results: We performed microarray analysis on left ventricles of wild-type (WT) and cMyBPC-/- mice (n = 7 each) at postnatal day (PND) 1 and PND 9, before and after the appearance of an overt HCM phenotype. Applying the criteria of ≥2-fold change, we identified genes whose change was exclusive to pathophysiologic growth (n = 61), physiologic growth (n = 30), and genes whose expression changed ≥2-fold in both WT and cMyBP-C-/- hearts (n = 130). Furthermore, we identified genes that were dysregulated in PND1 cMyBP-C-/- hearts prior to hypertrophy, including genes in mechanosensing pathways and potassium channels linked to arrhythmias. One gene of interest, Xirp2, and its protein product, are regulated during growth but also show early, robust prehypertrophic upregulation in cMyBP-C-/- hearts. Additionally, the transcription factor Zbtb16 also shows prehypertrophic upregulation at both gene and protein levels. Conclusion: Our transcriptome analysis generated a comprehensive data set comparing physiologic vs. hypertrophic growth in mice lacking cMyBP-C. It highlights the importance of extracellular matrix pathways in hypertrophic growth and early dysregulation of potassium channels. Prehypertrophic upregulation of Xirp2 in cMyBP-C-/- hearts supports a growing body of evidence suggesting Xirp2 has the capacity to elicit both hypertrophy and arrhythmias in HCM. Dysregulation of Xirp2, as well as Zbtb16, along with other genes associated with mechanosensing regions of the cardiomyocyte implicate stress-sensing in these regions as a potentially important early response in HCM.
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Affiliation(s)
- Emily Farrell
- Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
| | - Annie E Armstrong
- Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
| | - Adrian C Grimes
- Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
| | - Francisco J Naya
- Department of Biology, Boston University, Boston, MA, United States
| | - Willem J de Lange
- Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
| | - J Carter Ralphe
- Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
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Weissler-Snir A, Adler A, Williams L, Gruner C, Rakowski H. Prevention of sudden death in hypertrophic cardiomyopathy: bridging the gaps in knowledge. Eur Heart J 2018; 38:1728-1737. [PMID: 27371714 DOI: 10.1093/eurheartj/ehw268] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 06/01/2016] [Indexed: 12/12/2022] Open
Abstract
Sudden cardiac death (SCD) is the most devastating complication of hypertrophic cardiomyopathy (HCM). Although the annual rate of SCD in the general HCM population is <1% per year according to contemporary series, there is still a small subset of patients who are at increased risk of SCD. The greatest challenge in the management of HCM is identifying those at increased risk as an implantable cardioverter defibrillator is a potentially life-saving therapy. In this review, we sought to summarize the available data on SCD in HCM and provide a clinical perspective on the current differing and somewhat conflicting European and American recommendations on risk stratification, with balanced guidance with regards to rational clinical decision making. Additionally, we sought to learn more on the actual implementation of the guidelines by HCM experts worldwide.
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Affiliation(s)
- Adaya Weissler-Snir
- Division of Cardiology, Peter Munk Cardiac Centre, Toronto General Hospital, University Health Network, Toronto, ON, Canada
| | - Arnon Adler
- Division of Cardiology, Peter Munk Cardiac Centre, Toronto General Hospital, University Health Network, Toronto, ON, Canada
| | - Lynne Williams
- Papworth Hospital NHS Foundation Trust, Papworth Everard, Cambridge, UK
| | - Christiane Gruner
- Division of Cardiology, Cardiovascular Centre, University Hospital Zurich, Zurich, Switzerland
| | - Harry Rakowski
- Division of Cardiology, Peter Munk Cardiac Centre, Toronto General Hospital, University Health Network, Toronto, ON, Canada
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10
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Mathew J, Zahavich L, Lafreniere-Roula M, Wilson J, George K, Benson L, Bowdin S, Mital S. Utility of genetics for risk stratification in pediatric hypertrophic cardiomyopathy. Clin Genet 2017; 93:310-319. [DOI: 10.1111/cge.13157] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 09/17/2017] [Accepted: 09/27/2017] [Indexed: 12/29/2022]
Affiliation(s)
- J. Mathew
- Cardiology Department; The Royal Children’s Hospital; Melbourne Victoria Australia
| | - L. Zahavich
- Division of Cardiology, Department of Pediatrics; Hospital for Sick Children, University of Toronto; Toronto Ontario Canada
| | - M. Lafreniere-Roula
- Division of Cardiology, Department of Pediatrics; Hospital for Sick Children, University of Toronto; Toronto Ontario Canada
| | - J. Wilson
- Division of Cardiology, Department of Pediatrics; Hospital for Sick Children, University of Toronto; Toronto Ontario Canada
| | - K. George
- Division of Cardiology, Department of Pediatrics; Hospital for Sick Children, University of Toronto; Toronto Ontario Canada
| | - L. Benson
- Division of Cardiology, Department of Pediatrics; Hospital for Sick Children, University of Toronto; Toronto Ontario Canada
| | - S. Bowdin
- Division of Cardiology, Department of Pediatrics; Hospital for Sick Children, University of Toronto; Toronto Ontario Canada
| | - S. Mital
- Division of Cardiology, Department of Pediatrics; Hospital for Sick Children, University of Toronto; Toronto Ontario Canada
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Farrell ET, Grimes AC, de Lange WJ, Armstrong AE, Ralphe JC. Increased Postnatal Cardiac Hyperplasia Precedes Cardiomyocyte Hypertrophy in a Model of Hypertrophic Cardiomyopathy. Front Physiol 2017; 8:414. [PMID: 28659827 PMCID: PMC5470088 DOI: 10.3389/fphys.2017.00414] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 05/30/2017] [Indexed: 01/17/2023] Open
Abstract
Rationale: Hypertrophic cardiomyopathy (HCM) occurs in ~0.5% of the population and is a leading cause of sudden cardiac death (SCD) in young adults. Cardiomyocyte hypertrophy has been the accepted mechanism for cardiac enlargement in HCM, but the early signaling responsible for initiating hypertrophy is poorly understood. Mutations in cardiac myosin binding protein C (MYBPC3) are among the most common HCM-causing mutations. Ablation of Mybpc3 in an HCM mouse model (cMyBP-C−/−) rapidly leads to cardiomegaly by postnatal day (PND) 9, though hearts are indistinguishable from wild-type (WT) at birth. This model provides a unique opportunity to explore early processes involved in the dramatic postnatal transition to hypertrophy. Methods and Results: We performed microarray analysis, echocardiography, qPCR, immunohistochemistry (IHC), and isolated cardiomyocyte measurements to characterize the perinatal cMyBP-C−/− phenotype before and after overt hypertrophy. cMyBP-C−/− hearts showed elevated cell cycling at PND1 that transitioned to hypertrophy by PND9. An expanded time course revealed that increased cardiomyocyte cycling was associated with elevated heart weight to body weight ratios prior to cellular hypertrophy, suggesting that cell cycling resulted in cardiomyocyte proliferation. Animals heterozygous for the cMyBP-C deletion trended in the direction of the homozygous null, yet did not show increased heart size by PND9. Conclusions: Results indicate that altered regulation of the cell cycling pathway and elevated proliferation precedes hypertrophy in the cMyBP-C−/− HCM model, and suggests that increased cardiomyocyte number contributes to increased heart size in cMyBP-C−/− mice. This pre-hypertrophic period may reflect a unique time during which the commitment to HCM is determined and disease severity is influenced.
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Affiliation(s)
- Emily T Farrell
- Department of Pediatrics, University of Wisconsin School of Medicine and Public HealthMadison, WI, United States
| | - Adrian C Grimes
- Department of Medicine, University of Wisconsin School of Medicine and Public HealthMadison, WI, United States
| | - Willem J de Lange
- Department of Pediatrics, University of Wisconsin School of Medicine and Public HealthMadison, WI, United States
| | - Annie E Armstrong
- Department of Pediatrics, University of Wisconsin School of Medicine and Public HealthMadison, WI, United States
| | - J Carter Ralphe
- Department of Pediatrics, University of Wisconsin School of Medicine and Public HealthMadison, WI, United States
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12
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Abstract
There has been a significant progress in our understanding of the molecular mechanisms by which calcium (Ca2+) ions mediate various types of cardiac arrhythmias. A growing list of inherited gene defects can cause potentially lethal cardiac arrhythmia syndromes, including catecholaminergic polymorphic ventricular tachycardia, congenital long QT syndrome, and hypertrophic cardiomyopathy. In addition, acquired deficits of multiple Ca2+-handling proteins can contribute to the pathogenesis of arrhythmias in patients with various types of heart disease. In this review article, we will first review the key role of Ca2+ in normal cardiac function-in particular, excitation-contraction coupling and normal electric rhythms. The functional involvement of Ca2+ in distinct arrhythmia mechanisms will be discussed, followed by various inherited arrhythmia syndromes caused by mutations in Ca2+-handling proteins. Finally, we will discuss how changes in the expression of regulation of Ca2+ channels and transporters can cause acquired arrhythmias, and how these mechanisms might be targeted for therapeutic purposes.
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Affiliation(s)
- Andrew P Landstrom
- From the Section of Cardiology, Department of Pediatrics (A.P.L.), Cardiovascular Research Institute (A.P.L., X.H.T.W.), and Departments of Molecular Physiology and Biophysics, Medicine (Cardiology), Center for Space Medicine (X.H.T.W.), Baylor College of Medicine, Houston, TX; and Institute of Pharmacology, West German Heart and Vascular Center, University Duisburg-Essen, Essen, Germany (D.D.)
| | - Dobromir Dobrev
- From the Section of Cardiology, Department of Pediatrics (A.P.L.), Cardiovascular Research Institute (A.P.L., X.H.T.W.), and Departments of Molecular Physiology and Biophysics, Medicine (Cardiology), Center for Space Medicine (X.H.T.W.), Baylor College of Medicine, Houston, TX; and Institute of Pharmacology, West German Heart and Vascular Center, University Duisburg-Essen, Essen, Germany (D.D.)
| | - Xander H T Wehrens
- From the Section of Cardiology, Department of Pediatrics (A.P.L.), Cardiovascular Research Institute (A.P.L., X.H.T.W.), and Departments of Molecular Physiology and Biophysics, Medicine (Cardiology), Center for Space Medicine (X.H.T.W.), Baylor College of Medicine, Houston, TX; and Institute of Pharmacology, West German Heart and Vascular Center, University Duisburg-Essen, Essen, Germany (D.D.).
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13
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García-Giustiniani D, Arad M, Ortíz-Genga M, Barriales-Villa R, Fernández X, Rodríguez-García I, Mazzanti A, Veira E, Maneiro E, Rebolo P, Lesende I, Cazón L, Freimark D, Gimeno-Blanes JR, Seidman C, Seidman J, McKenna W, Monserrat L. Phenotype and prognostic correlations of the converter region mutations affecting the β myosin heavy chain. Heart 2015; 101:1047-53. [PMID: 25935763 PMCID: PMC4484257 DOI: 10.1136/heartjnl-2014-307205] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Accepted: 03/30/2015] [Indexed: 12/01/2022] Open
Abstract
Objectives The prognostic value of genetic studies in cardiomyopathies is still controversial. Our objective was to evaluate the outcome of patients with cardiomyopathy with mutations in the converter domain of β myosin heavy chain (MYH7). Methods Clinical characteristics and survival of 117 affected members with mutations in the converter domain of MYH7 were compared with 409 patients described in the literature with mutations in the same region. Results Twenty-five mutations were evaluated (9 in our families including 3 novel (Ile730Asn, Asp717Gly and Arg719Pro)). Clinical diagnoses were hypertrophic (n=407), dilated (n=15), non-compaction (n=4) and restrictive (n=5) cardiomyopathies, unspecified cardiomyopathy (n=11), sudden death (n=50) and 35 healthy carriers. One hundred eighty-four had events (cardiovascular death or transplant). Median event-free survival was 50±2 years in our patients and 53±3 years in the literature (p=0.27). There were significant differences in the outcome between mutation: Ile736Thr had fewer events than other mutations in the region (p=0.01), while Arg719Gln (p<0.01) had reduced event-free survival. Conclusions Mutations in the converter region are generally associated with adverse prognosis although there are differences between mutations. The identification of a mutation in this particular region provides important prognostic information that should be considered in the clinical management of affected patients.
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Affiliation(s)
| | - Michael Arad
- Leviev Heart Center, Sheba Medical Centre, and Tel Aviv University, Tel Aviv, Israel
| | | | - Roberto Barriales-Villa
- Inherited Cardiovascular Disease Unit, Instituto de Investigación Biomédica de A Coruña (INIBIC), Complexo Hospitalario Universitario de A Coruña (CHUAC), Sergas Universidade da Coruña (UDC), A Coruña, Spain Red de Investigación Cardiovascular (RIC); RD12/0042/0069, A Coruña, Spain
| | - Xusto Fernández
- Red de Investigación Cardiovascular (RIC); RD12/0042/0069, A Coruña, Spain
| | - Isabel Rodríguez-García
- Inherited Cardiovascular Disease Unit, Instituto de Investigación Biomédica de A Coruña (INIBIC), Complexo Hospitalario Universitario de A Coruña (CHUAC), Sergas Universidade da Coruña (UDC), A Coruña, Spain
| | | | | | | | | | | | - Laura Cazón
- Red de Investigación Cardiovascular (RIC); RD12/0042/0069, A Coruña, Spain
| | - Dov Freimark
- Leviev Heart Center, Sheba Medical Centre, and Tel Aviv University, Tel Aviv, Israel
| | | | - Christine Seidman
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA
| | - Jonathan Seidman
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA
| | | | - Lorenzo Monserrat
- Health in Code, A Coruña, Spain Inherited Cardiovascular Disease Unit, Instituto de Investigación Biomédica de A Coruña (INIBIC), Complexo Hospitalario Universitario de A Coruña (CHUAC), Sergas Universidade da Coruña (UDC), A Coruña, Spain
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14
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A novel de novo mutation of β-cardiac myosin heavy chain gene found in a twelve-year-old boy with hypertrophic cardiomyopathy. J Genet 2015; 93:557-60. [PMID: 25189259 DOI: 10.1007/s12041-014-0414-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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15
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Blankenburg R, Hackert K, Wurster S, Deenen R, Seidman JG, Seidman CE, Lohse MJ, Schmitt JP. β-Myosin heavy chain variant Val606Met causes very mild hypertrophic cardiomyopathy in mice, but exacerbates HCM phenotypes in mice carrying other HCM mutations. Circ Res 2014; 115:227-37. [PMID: 24829265 DOI: 10.1161/circresaha.115.303178] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE Approximately 40% of hypertrophic cardiomyopathy (HCM) is caused by heterozygous missense mutations in β-cardiac myosin heavy chain (β-MHC). Associating disease phenotype with mutation is confounded by extensive background genetic and lifestyle/environmental differences between subjects even from the same family. OBJECTIVE To characterize disease caused by β-cardiac myosin heavy chain Val606Met substitution (VM) that has been identified in several HCM families with wide variation of clinical outcomes, in mice. METHODS AND RESULTS Unlike 2 mouse lines bearing the malignant myosin mutations Arg453Cys (RC/+) or Arg719Trp (RW/+), VM/+ mice with an identical inbred genetic background lacked hallmarks of HCM such as left ventricular hypertrophy, disarray of myofibers, and interstitial fibrosis. Even homozygous VM/VM mice were indistinguishable from wild-type animals, whereas RC/RC- and RW/RW-mutant mice died within 9 days after birth. However, hypertrophic effects of the VM mutation were observed both in mice treated with cyclosporine, a known stimulator of the HCM response, and compound VM/RC heterozygous mice, which developed a severe HCM phenotype. In contrast to all heterozygous mutants, both systolic and diastolic function of VM/RC hearts was severely impaired already before the onset of cardiac remodeling. CONCLUSIONS The VM mutation per se causes mild HCM-related phenotypes; however, in combination with other HCM activators it exacerbates the HCM phenotype. Double-mutant mice are suitable for assessing the severity of benign mutations.
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Affiliation(s)
- Robert Blankenburg
- From the Institute of Pharmacology and Toxicology, University of Würzburg, Würzburg, Germany (R.B., S.W., M.J.L., J.P.S.); Institute of Pharmacology and Clinical Pharmacology, University Hospital Düsseldorf and Cardiovascular Research Institute Düsseldorf (CARID), Heinrich-Heine-University, Düsseldorf, Germany (K.H., J.P.S.); Cardiovascular Division, Brigham and Women's Hospital, Boston, MA (C.E.S.); Department of Genetics, Harvard Medical School, Boston, MA (J.G.S.); and Bio-Medical Research Center (BMFZ), Heinrich-Heine-University, Düsseldorf, Germany (R.D.)
| | - Katarzyna Hackert
- From the Institute of Pharmacology and Toxicology, University of Würzburg, Würzburg, Germany (R.B., S.W., M.J.L., J.P.S.); Institute of Pharmacology and Clinical Pharmacology, University Hospital Düsseldorf and Cardiovascular Research Institute Düsseldorf (CARID), Heinrich-Heine-University, Düsseldorf, Germany (K.H., J.P.S.); Cardiovascular Division, Brigham and Women's Hospital, Boston, MA (C.E.S.); Department of Genetics, Harvard Medical School, Boston, MA (J.G.S.); and Bio-Medical Research Center (BMFZ), Heinrich-Heine-University, Düsseldorf, Germany (R.D.)
| | - Sebastian Wurster
- From the Institute of Pharmacology and Toxicology, University of Würzburg, Würzburg, Germany (R.B., S.W., M.J.L., J.P.S.); Institute of Pharmacology and Clinical Pharmacology, University Hospital Düsseldorf and Cardiovascular Research Institute Düsseldorf (CARID), Heinrich-Heine-University, Düsseldorf, Germany (K.H., J.P.S.); Cardiovascular Division, Brigham and Women's Hospital, Boston, MA (C.E.S.); Department of Genetics, Harvard Medical School, Boston, MA (J.G.S.); and Bio-Medical Research Center (BMFZ), Heinrich-Heine-University, Düsseldorf, Germany (R.D.)
| | - René Deenen
- From the Institute of Pharmacology and Toxicology, University of Würzburg, Würzburg, Germany (R.B., S.W., M.J.L., J.P.S.); Institute of Pharmacology and Clinical Pharmacology, University Hospital Düsseldorf and Cardiovascular Research Institute Düsseldorf (CARID), Heinrich-Heine-University, Düsseldorf, Germany (K.H., J.P.S.); Cardiovascular Division, Brigham and Women's Hospital, Boston, MA (C.E.S.); Department of Genetics, Harvard Medical School, Boston, MA (J.G.S.); and Bio-Medical Research Center (BMFZ), Heinrich-Heine-University, Düsseldorf, Germany (R.D.)
| | - J G Seidman
- From the Institute of Pharmacology and Toxicology, University of Würzburg, Würzburg, Germany (R.B., S.W., M.J.L., J.P.S.); Institute of Pharmacology and Clinical Pharmacology, University Hospital Düsseldorf and Cardiovascular Research Institute Düsseldorf (CARID), Heinrich-Heine-University, Düsseldorf, Germany (K.H., J.P.S.); Cardiovascular Division, Brigham and Women's Hospital, Boston, MA (C.E.S.); Department of Genetics, Harvard Medical School, Boston, MA (J.G.S.); and Bio-Medical Research Center (BMFZ), Heinrich-Heine-University, Düsseldorf, Germany (R.D.)
| | - Christine E Seidman
- From the Institute of Pharmacology and Toxicology, University of Würzburg, Würzburg, Germany (R.B., S.W., M.J.L., J.P.S.); Institute of Pharmacology and Clinical Pharmacology, University Hospital Düsseldorf and Cardiovascular Research Institute Düsseldorf (CARID), Heinrich-Heine-University, Düsseldorf, Germany (K.H., J.P.S.); Cardiovascular Division, Brigham and Women's Hospital, Boston, MA (C.E.S.); Department of Genetics, Harvard Medical School, Boston, MA (J.G.S.); and Bio-Medical Research Center (BMFZ), Heinrich-Heine-University, Düsseldorf, Germany (R.D.)
| | - Martin J Lohse
- From the Institute of Pharmacology and Toxicology, University of Würzburg, Würzburg, Germany (R.B., S.W., M.J.L., J.P.S.); Institute of Pharmacology and Clinical Pharmacology, University Hospital Düsseldorf and Cardiovascular Research Institute Düsseldorf (CARID), Heinrich-Heine-University, Düsseldorf, Germany (K.H., J.P.S.); Cardiovascular Division, Brigham and Women's Hospital, Boston, MA (C.E.S.); Department of Genetics, Harvard Medical School, Boston, MA (J.G.S.); and Bio-Medical Research Center (BMFZ), Heinrich-Heine-University, Düsseldorf, Germany (R.D.)
| | - Joachim P Schmitt
- From the Institute of Pharmacology and Toxicology, University of Würzburg, Würzburg, Germany (R.B., S.W., M.J.L., J.P.S.); Institute of Pharmacology and Clinical Pharmacology, University Hospital Düsseldorf and Cardiovascular Research Institute Düsseldorf (CARID), Heinrich-Heine-University, Düsseldorf, Germany (K.H., J.P.S.); Cardiovascular Division, Brigham and Women's Hospital, Boston, MA (C.E.S.); Department of Genetics, Harvard Medical School, Boston, MA (J.G.S.); and Bio-Medical Research Center (BMFZ), Heinrich-Heine-University, Düsseldorf, Germany (R.D.).
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16
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Abstract
Hypertrophic cardiomyopathy is a common inherited heart muscle disorder associated with sudden cardiac death, arrhythmias and heart failure. Genetic mutations can be identified in approximately 60% of patients; these are commonest in genes that encode proteins of the cardiac sarcomere. Similar to other Mendelian diseases these mutations are characterized by incomplete penetrance and variable clinical expression. Our knowledge of this genetic diversity is rapidly evolving as high-throughput DNA sequencing technology is now used to characterize an individual patient's disease. In addition, the genomic basis of several multisystem diseases associated with a hypertrophic cardiomyopathy phenotype has been elucidated. Genetic biomarkers can be helpful in making an accurate diagnosis and in identifying relatives at risk of developing the condition. In the clinical setting, genetic testing and genetic screening should be used pragmatically with appropriate counseling. Here we review the current role of genetic biomarkers in hypertrophic cardiomyopathy, highlight recent progress in the field and discuss future challenges.
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Affiliation(s)
- Caroline J Coats
- The Heart Hospital, 16-18 Westmoreland Street, London, W1G 8PH, UK
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17
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Using genetic testing to guide therapeutic decisions in cardiomyopathy. CURRENT TREATMENT OPTIONS IN CARDIOVASCULAR MEDICINE 2013; 15:387-96. [PMID: 23794152 DOI: 10.1007/s11936-013-0252-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
OPINION STATEMENT Genetic analysis of human cardiomyopathy has rapidly transitioned from a strictly research endeavor to a diagnostic tool readily available to clinicians across the globe. In contemporary practice, genetic testing improves the efficiency of family evaluations and clarifies the etiology of ambiguous clinical presentations. The great promise of genetic diagnosis is to enable preventative therapies for individuals at high risk of future disease development, a strategy that is under active clinical investigation. However, in the present and future, careful interpretation of DNA sequence variation is critical, and can be ensured by referral to a specialized cardiovascular genetics clinic.
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18
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Lopes LR, Rahman MS, Elliott PM. A systematic review and meta-analysis of genotype-phenotype associations in patients with hypertrophic cardiomyopathy caused by sarcomeric protein mutations. Heart 2013; 99:1800-11. [PMID: 23674365 DOI: 10.1136/heartjnl-2013-303939] [Citation(s) in RCA: 140] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
BACKGROUND The genetic basis of familial hypertrophic cardiomyopathy (HCM) is well described, but the relation between genotype and clinical phenotype is still poorly characterised. OBJECTIVE To summarise and critically review the current literature on genotype-phenotype associations in patients with HCM and to perform a meta-analysis on selected clinical features. DATA SOURCES PubMed/Medline was searched up to January 2013. Retrieved articles were checked for additional publications. SELECTION CRITERIA Observational, cross-sectional and prospectively designed English language human studies that analysed the relationship between the presence of mutations in sarcomeric protein genes and clinical parameters. DATA EXTRACTION AND ANALYSIS The pooled analysis was confined to studies reporting on cohorts of unrelated and consecutive patients in which at least two sarcomere genes were sequenced. A random effect meta-regression model was used to determine the overall prevalence of predefined clinical features: age at presentation, gender, family history of HCM, family history of sudden cardiac death (SCD), and maximum left ventricular wall thickness (MLVWT). The I(2) statistic was used to estimate the proportion of total variability in the prevalence data attributable to the heterogeneity between studies. RESULTS Eighteen publications (corresponding to a total of 2459 patients) were selected for the pooled analysis. The presence of any sarcomere gene mutation was associated with a younger age at presentation (38.4 vs 46.0 years, p<0.0005), a family history of HCM (50.6% vs 23.1%, p<0.0005), a family history of SCD (27.0% vs 14.9%, p<0.0005) and greater MLVWT (21.0 vs 19.3 mm, p=0.03). There were no differences when the two most frequently affected genes, MYBPC3 and MYH7, were compared. A total of 53 family studies were also included in the review. These were characterised by pronounced variability and the majority of studies reporting on outcomes analysed small cross-sectional cohorts and were unsuitable for pooled analyses. CONCLUSIONS The presence of a mutation in any sarcomere gene is associated with a number of clinical features. The heterogeneous nature of the disease and the inconsistency of study design precludes the establishment of more precise genotype-phenotype relationships. Large scale studies examining the relation between genotype, disease severity, and prognosis are required.
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Affiliation(s)
- Luís R Lopes
- Institute of Cardiovascular Science, University College London, , London, UK
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19
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Marian A. Recent advances in genetics and treatment of hypertrophic cardiomyopathy. Future Cardiol 2012; 1:341-53. [PMID: 19804117 DOI: 10.1517/14796678.1.3.341] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Hypertrophic cardiomyopathy (HCM) is an intriguing disease with various clinical manifestations, ranging from sudden cardiac death to heart failure. The molecular genetics of HCM are all but elucidated and over 200 mutations in more than a dozen genes have been identified. Conventional therapeutic agents, namely beta-blockers and calcium channel blockers, could provide symptomatic relief but are not known to reduce mortality or induce regression of phenotype. Studies in genetic animal models suggest cardiac hypertrophy and fibrosis, a major histological feature of HCM, may be reversed or prevented through blockade of molecules involved in the pathogenesis of HCM. Surgical myomectomy and ethanol-induced septal ablation are effective procedures for reducing the left ventricular outflow tract obstruction and hence, symptomatic improvement. Randomized studies are needed to compare the effectiveness of medical therapy, ethanol septal ablation and surgical myomectomy in treatment of patients with HCM.
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Affiliation(s)
- Aj Marian
- Baylor College of Medicine, One Baylor Plaza, 519D Houston, TX 77030, USA.
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20
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Tripathi S, Schultz I, Becker E, Montag J, Borchert B, Francino A, Navarro-Lopez F, Perrot A, Özcelik C, Osterziel KJ, McKenna WJ, Brenner B, Kraft T. Unequal allelic expression of wild-type and mutated β-myosin in familial hypertrophic cardiomyopathy. Basic Res Cardiol 2011; 106:1041-55. [PMID: 21769673 PMCID: PMC3228959 DOI: 10.1007/s00395-011-0205-9] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Revised: 06/29/2011] [Accepted: 07/07/2011] [Indexed: 11/29/2022]
Abstract
Familial hypertrophic cardiomyopathy (FHC) is an autosomal dominant disease, which in about 30% of the patients is caused by missense mutations in one allele of the β-myosin heavy chain (β-MHC) gene (MYH7). To address potential molecular mechanisms underlying the family-specific prognosis, we determined the relative expression of mutant versus wild-type MYH7-mRNA. We found a hitherto unknown mutation-dependent unequal expression of mutant to wild-type MYH7-mRNA, which is paralleled by similar unequal expression of β-MHC at the protein level. Relative abundance of mutated versus wild-type MYH7-mRNA was determined by a specific restriction digest approach and by real-time PCR (RT-qPCR). Fourteen samples from M. soleus and myocardium of 12 genotyped and clinically well-characterized FHC patients were analyzed. The fraction of mutated MYH7-mRNA in five patients with mutation R723G averaged to 66 and 68% of total MYH7-mRNA in soleus and myocardium, respectively. For mutations I736T, R719W and V606M, fractions of mutated MYH7-mRNA in M. soleus were 39, 57 and 29%, respectively. For all mutations, unequal abundance was similar at the protein level. Importantly, fractions of mutated transcripts were comparable among siblings, in younger relatives and unrelated carriers of the same mutation. Hence, the extent of unequal expression of mutated versus wild-type transcript and protein is characteristic for each mutation, implying cis-acting regulatory mechanisms. Bioinformatics suggest mRNA stability or splicing effectors to be affected by certain mutations. Intriguingly, we observed a correlation between disease expression and fraction of mutated mRNA and protein. This strongly suggests that mutation-specific allelic imbalance represents a new pathogenic factor for FHC.
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Affiliation(s)
- Snigdha Tripathi
- Institute of Molecular and Cell Physiology, Hannover Medical School, Carl Neuberg Str. 1, 30625 Hannover, Germany
| | - Imke Schultz
- Institute of Molecular and Cell Physiology, Hannover Medical School, Carl Neuberg Str. 1, 30625 Hannover, Germany
- Present Address: Niederwiesenring 4, 63110 Rodgau, Germany
| | - Edgar Becker
- Institute of Molecular and Cell Physiology, Hannover Medical School, Carl Neuberg Str. 1, 30625 Hannover, Germany
| | - Judith Montag
- Institute of Molecular and Cell Physiology, Hannover Medical School, Carl Neuberg Str. 1, 30625 Hannover, Germany
| | - Bianca Borchert
- Institute of Molecular and Cell Physiology, Hannover Medical School, Carl Neuberg Str. 1, 30625 Hannover, Germany
- Present Address: Department of Cardiac, Thoracic, Transplantation and Vascular Surgery, Hannover Medical School, Carl-Neuberg Str. 1, 30625 Hannover, Germany
| | - Antonio Francino
- Hospital Clinic/IDIBAPS, University of Barcelona, 08036 Barcelona, Spain
| | | | - Andreas Perrot
- Charité-Unversitätsmedizin Berlin, Experimental and Clinical Research Center (ECRC) am Max-Delbrück-Centrum für Molekulare Medizin, Kardio-Genetisches Labor, 13125 Berlin, Germany
| | - Cemil Özcelik
- Charité-Unversitätsmedizin Berlin, Experimental and Clinical Research Center (ECRC) am Max-Delbrück-Centrum für Molekulare Medizin, Kardio-Genetisches Labor, 13125 Berlin, Germany
- Charité-Universitätsmedizin Berlin, Kardiologie am Campus Virchow-Klinikum, 13353 Berlin, Germany
| | - Karl-Josef Osterziel
- Charité-Universitätsmedizin Berlin, Kardiologie am Campus Virchow-Klinikum, 13353 Berlin, Germany
- Present Address: Kardiologische Gemeinschaftspraxis, Marienstraße 9, 92224 Amberg, Germany
| | - William J. McKenna
- Institute of Cardiovascular Science, University College London, London, WC1E 6BT United Kingdom
| | - Bernhard Brenner
- Institute of Molecular and Cell Physiology, Hannover Medical School, Carl Neuberg Str. 1, 30625 Hannover, Germany
| | - Theresia Kraft
- Institute of Molecular and Cell Physiology, Hannover Medical School, Carl Neuberg Str. 1, 30625 Hannover, Germany
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21
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Lee MS, Macrae CA. Revisiting risk stratification in hypertrophic cardiomyopathy: do we need to start from scratch? Heart Rhythm 2011; 9:64-5. [PMID: 22019864 DOI: 10.1016/j.hrthm.2011.10.023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2011] [Indexed: 12/28/2022]
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22
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Christiaans I, Nannenberg EA, Dooijes D, Jongbloed RJE, Michels M, Postema PG, Majoor-Krakauer D, van den Wijngaard A, Mannens MMAM, van Tintelen JP, van Langen IM, Wilde AAM. Founder mutations in hypertrophic cardiomyopathy patients in the Netherlands. Neth Heart J 2011; 18:248-54. [PMID: 20505798 DOI: 10.1007/bf03091771] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
In this part of a series on cardiogenetic founder mutations in the Netherlands, we review the Dutch founder mutations in hypertrophic cardiomyopathy (HCM) patients. HCM is a common autosomal dominant genetic disease affecting at least one in 500 persons in the general population. Worldwide, most mutations in HCM patients are identified in genes encoding sarcomeric proteins, mainly in the myosin-binding protein C gene (MYBPC3, OMIM #600958) and the beta myosin heavy chain gene (MYH7, OMIM #160760). In the Netherlands, the great majority of mutations occur in the MYBPC3, involving mainly three Dutch founder mutations in the MYBPC3 gene, the c.2373_2374insG, the c.2864_2865delCT and the c.2827C>T mutation. In this review, we describe the genetics of HCM, the genotype-phenotype relation of Dutch founder MYBPC3 gene mutations, the prevalence and the geographic distribution of the Dutch founder mutations, and the consequences for genetic counselling and testing. (Neth Heart J 2010;18:248-54.).
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Affiliation(s)
- I Christiaans
- Department of Clinical Genetics, Academic Medical Centre, Amsterdam, the Netherlands These authors contributed equally
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23
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Bai F, Weis A, Takeda AK, Chase PB, Kawai M. Enhanced active cross-bridges during diastole: molecular pathogenesis of tropomyosin's HCM mutations. Biophys J 2011; 100:1014-23. [PMID: 21320446 DOI: 10.1016/j.bpj.2011.01.001] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2010] [Revised: 12/22/2010] [Accepted: 01/03/2011] [Indexed: 11/28/2022] Open
Abstract
Three HCM-causing tropomyosin (Tm) mutants (V95A, D175N, and E180G) were examined using the thin-filament extraction and reconstitution technique. The effects of Ca(2+), ATP, phosphate, and ADP concentrations on cross-bridge kinetics in myocardium reconstituted with each of these mutants were studied at 25°C, and compared to wild-type (WT) Tm at physiological ionic strength (200 mM). All three mutants showed significantly higher (2-3.5 fold) low Ca(2+) tension (T(LC)) and stiffness than WT at pCa 8.0. High Ca(2+) tension (T(HC)) was significantly higher for E180G than that for WT, whereas T(HC) of V95A and D175N was similar to WT; high Ca(2+) stiffness (Y(HC)) had the same trend. The Ca(2+) sensitivity of isometric force was significantly greater for V95A and E180G than for WT, whereas that of D175N remained the same as for WT; for all mutants, cooperativity was lower than for WT. Nine kinetic constants and the cross-bridge distribution were deduced using sinusoidal analysis. The number of force-generating cross bridges was similar among the D175N, E180G, and WT Tm forms, but it was significantly larger in the case of V95A than WT. We conclude that the increased number of actively cycling cross bridges at pCa 8 is the major cause of Tm mutation-related HCM pathogenesis, which may result in diastolic dysfunction. Decreased contractility (T(act)) in V95A and D175N may further contribute to the severity of myocyte hypertrophy and related prognosis of the disease.
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Affiliation(s)
- Fan Bai
- Department of Anatomy and Cell Biology, University of Iowa, Iowa City, Iowa, USA
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Carstens N, van der Merwe L, Revera M, Heradien M, Goosen A, Brink PA, Moolman-Smook JC. Genetic variation in angiotensin II type 2 receptor gene influences extent of left ventricular hypertrophy in hypertrophic cardiomyopathy independent of blood pressure. J Renin Angiotensin Aldosterone Syst 2010; 12:274-80. [DOI: 10.1177/1470320310390725] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Introduction. Hypertrophic cardiomyopathy (HCM), an inherited primary cardiac disorder mostly caused by defective sarcomeric proteins, serves as a model to investigate left ventricular hypertrophy (LVH). HCM manifests extreme variability in the degree and distribution of LVH, even in patients with the same causal mutation. Genes coding for renin—angiotensin—aldosterone system components have been studied as hypertrophy modifiers in HCM, with emphasis on the angiotensin (Ang) II type 1 receptor (AT1R). However, Ang II binding to Ang II type 2 receptors (AT2R) also has hypertrophy-modulating effects. Methods. We investigated the effect of the functional +1675 G/A polymorphism (rs1403543) and additional single nucleotide polymorphisms in the 3’ untranslated region of the AT2R gene ( AGTR2) on a heritable composite hypertrophy score in an HCM family cohort in which HCM founder mutations segregate. Results. We find significant association between rs1403543 and hypertrophy, with each A allele decreasing the average wall thickness by ~0.5 mm, independent of the effects of the primary HCM causal mutation, blood pressure and other hypertrophy covariates ( p = 0.020). Conclusion. This study therefore confirms a hypertrophy-modulating effect for AT2R also in HCM and implies that +1675 G/A could potentially be used in a panel of markers that profile a genetic predisposition to LVH in HCM.
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Affiliation(s)
- Nadia Carstens
- MRC Centre for Molecular and Cellular Biology, Department of Biomedical Sciences, University of Stellenbosch Health Sciences Faculty, Tygerberg, South Africa
| | - Lize van der Merwe
- Biostatistics Unit, Medical Research Council of South Africa, Tygerberg, South Africa, Department of Statistics, University of Western Cape, Bellville, South Africa
| | - Miriam Revera
- Department of Cardiology, IRCCS San Matteo Hospital, Pavia, Italy
| | - Marshall Heradien
- Department of Medicine, University of Stellenbosch Health Sciences Faculty, Tygerberg, South Africa
| | - Althea Goosen
- Department of Medicine, University of Stellenbosch Health Sciences Faculty, Tygerberg, South Africa
| | - Paul A Brink
- Department of Medicine, University of Stellenbosch Health Sciences Faculty, Tygerberg, South Africa
| | - Johanna C Moolman-Smook
- MRC Centre for Molecular and Cellular Biology, Department of Biomedical Sciences, University of Stellenbosch Health Sciences Faculty, Tygerberg, South Africa,
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Landstrom AP, Ackerman MJ. Mutation type is not clinically useful in predicting prognosis in hypertrophic cardiomyopathy. Circulation 2010; 122:2441-9; discussion 2450. [PMID: 21135372 PMCID: PMC6309993 DOI: 10.1161/circulationaha.110.954446] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Hypertrophic cardiomyopathy (HCM), or clinically unexplained hypertrophy of the heart, is a common genetic cardiovascular disorder marked by genetic and phenotypic heterogeneity. As the genetic mutations underlying the pathogenesis of this disease have been identified, investigators have attempted to link mutations to clearly defined alterations in survival in hopes of identifying prognostically relevant biomarkers of disease. While initial studies labeling particular MYH7 -encoded beta myosin heavy chain and TNNT2 -encoded cardiac troponin T mutations as “malignant” or “benign” raised hopes for mutation-specific risk stratification in HCM, a series of subsequent investigations identified mutations in families with contradictory disease phenotypes. Furthermore, subsequent proband-based cohort studies indicated that the clinical prognostic relevance of individual mutations labeled as “malignant” or “benign” in large referral centers is negligible. Herein, we seek to summarize the controversy and dispute the notion that mutation-specific risk stratification in HCM is possible at the present time. We provide evidence for clinicians and basic scientists alike to move beyond simple mutation descriptors to a more nuanced understanding of HCM mutations that fully captures the multi-factorial nature of HCM disease expression.
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Affiliation(s)
- Andrew P Landstrom
- Department of Medicine, Division of Cardiovascular Diseases, and the Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, MN 55905, USA
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Zheng DD, Yang JH, Tao Q, Geng M, Lin J, Yang XJ, Song JP, Li HX, Han LH, Jiang WP. Mutations in the beta-myosin heavy chain gene in southern Chinese families with hypertrophic cardiomyopathy. J Int Med Res 2010; 38:810-20. [PMID: 20819418 DOI: 10.1177/147323001003800308] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
In this study, 14 unrelated hypertrophic cardiomyopathy (HCM) probands were scanned by polymerase chain reaction-single-strand conformation polymorphism analysis and DNA sequencing. Three mis-sense mutations of the beta-myosin heavy chain gene, MYH7, were found: valine (Val) 606 methionine (Met), arginine (Arg) 694 leucine (Leu), and Arg 723 glycine (Gly). All are reported here for the first time in Chinese subjects. The results showed that: Val606Met is an intermediate malignancy mutation; Arg694Leu is a novel mutation with a benign phenotype; and the Arg723Gly mutation is linked to malignancy - it can lead not only to HCM but also to dilated cardiomyopathy at various ages. The clinical symptoms associated with Arg723Gly emerged early and caused more severe clinical manifestation and poorer prognosis in females than in males. Mis-sense mutations were not detected in the myosin binding protein C, cardiac, cardiac troponin T type 2, or cardiac troponin I type 3 genes. The MYH7 gene may be an HCM mutation hotspot in the Chinese and have unique features in this study population.
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Affiliation(s)
- D D Zheng
- Department of Cardiology, First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China
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Witte DP, Aronow BJ, Harmony JAK. Understanding Cardiac Development Through the Perspective of Gene Regulation and Gene Manipulation. ACTA ACUST UNITED AC 2010. [DOI: 10.1080/15513819609169282] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Callis TE, Jensen BC, Weck KE, Willis MS. Evolving molecular diagnostics for familial cardiomyopathies: at the heart of it all. Expert Rev Mol Diagn 2010; 10:329-51. [PMID: 20370590 PMCID: PMC5022563 DOI: 10.1586/erm.10.13] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Cardiomyopathies are an important and heterogeneous group of common cardiac diseases. An increasing number of cardiomyopathies are now recognized to have familial forms, which result from single-gene mutations that render a Mendelian inheritance pattern, including hypertrophic cardiomyopathy, dilated cardiomyopathy, restrictive cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy and left ventricular noncompaction cardiomyopathy. Recently, clinical genetic tests for familial cardiomyopathies have become available for clinicians evaluating and treating patients with these diseases, making it necessary to understand the current progress and challenges in cardiomyopathy genetics and diagnostics. In this review, we summarize the genetic basis of selected cardiomyopathies, describe the clinical utility of genetic testing for cardiomyopathies and outline the current challenges and emerging developments.
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Affiliation(s)
- Thomas E Callis
- PGxHealth Division, Clinical Data, Inc., 5 Science Park, New Haven, CT 06511, USA
| | - Brian C Jensen
- McAllister Heart Institute, University of North Carolina, Chapel Hill, NC, 27599-7126, USA and Department of Internal Medicine, Section of Cardiology, University of North Carolina, Chapel Hill, NC 27599-7075, USA
| | - Karen E Weck
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC 27599-7525, USA
| | - Monte S Willis
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC 27599-7525, USA and McAllister Heart Institute, University of North Carolina at Chapel Hill, 2340B Medical Biomolecular Research Building, 103 Mason Farm Road, Chapel Hill, NC 27599-7525, USA Tel.: +1 919 843 1938 Fax: +1 919 843 4585
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Carasso S, Yang H, Woo A, Jamorski M, Wigle ED, Rakowski H. Diastolic Myocardial Mechanics in Hypertrophic Cardiomyopathy. J Am Soc Echocardiogr 2010; 23:164-71. [DOI: 10.1016/j.echo.2009.11.022] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2009] [Indexed: 11/16/2022]
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Christiaans I, van Engelen K, van Langen IM, Birnie E, Bonsel GJ, Elliott PM, Wilde AAM. Risk stratification for sudden cardiac death in hypertrophic cardiomyopathy: systematic review of clinical risk markers. Europace 2010; 12:313-21. [PMID: 20118111 DOI: 10.1093/europace/eup431] [Citation(s) in RCA: 124] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
We performed a systematic literature review of recommended 'major' and 'possible' clinical risk markers for sudden cardiac death (SCD) in hypertrophic cardiomyopathy (HCM). We searched the Medline, Embase and Cochrane databases for articles published between 1971 and 2007. We included English language reports on HCM patients containing follow-up data on the endpoint (sudden) cardiac death using survival analysis. Analysis was undertaken using the quality of reporting of meta-analyses (QUORUM) statement checklist. The quality was checked using a quality assessment form from the Cochrane Collaboration. Thirty studies met inclusion criteria and passed quality assessment. The use of the six major risk factors (previous cardiac arrest or sustained ventricular tachycardia, non-sustained ventricular tachycardia, extreme left ventricular hypertrophy, unexplained syncope, abnormal blood pressure response, and family history of sudden death) in risk stratification for SCD as recommended by international guidelines was supported by the literature. In addition, left ventricular outflow tract obstruction seems associated with a higher risk of SCD. Our systematic review provides sound evidence for the use of the six major risk factors for SCD in the risk stratification of HCM patients. Left ventricular outflow tract obstruction could be included in the overall risk profile of patients with a marked left ventricular outflow gradient under basal conditions.
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Affiliation(s)
- Imke Christiaans
- Department of Clinical Genetics, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
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Michels M, Soliman OI, Phefferkorn J, Hoedemaekers YM, Kofflard MJ, Dooijes D, Majoor-Krakauer D, Ten Cate FJ. Disease penetrance and risk stratification for sudden cardiac death in asymptomatic hypertrophic cardiomyopathy mutation carriers. Eur Heart J 2009; 30:2593-8. [DOI: 10.1093/eurheartj/ehp306] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
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Relationship between circulating levels of monocyte chemoattractant protein-1 and systolic dysfunction in patients with hypertrophic cardiomyopathy. Cardiovasc Pathol 2009; 18:317-22. [PMID: 19211266 DOI: 10.1016/j.carpath.2008.12.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2008] [Revised: 10/29/2008] [Accepted: 12/03/2008] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Progression of hypertrophic cardiomyopathy (HCM) to left ventricular dilatation and systolic dysfunction sometimes occurs. However, the mechanism of the transition from hypertrophy to dysfunction has not been elucidated. It has been reported that circulating levels of monocyte chemoattractant protein-1 (MCP-1), which is a major factor promoting the accumulation of macrophages, are increased in patients with congestive heart failure. We measured circulating levels of MCP-1 in patients with HCM and examined whether MCP-1 was expressed in the myocardium of HCM patients. We also examined whether circulating levels of MCP-1 were correlated with left ventricular dysfunction. METHODS Circulating levels of MCP-1 were measured by an enzyme immunoassay in 26 patients with HCM (60+/-2 years old) and 20 control subjects (57+/-2 years old). Cardiac function was evaluated by two-dimensional echocardiography and cardiac catheterization. RESULTS HCM patients had significantly elevated levels of MCP-1 (HCM: 309+/-30 vs. control: 178+/-8 pg/ml, P<.001). MCP-1 levels in patients with systolic dysfunction were significantly higher than those in patients without systolic dysfunction (P<.05) and were also significantly higher than those in patients with outflow obstruction (P<.05). Immunohistochemical analysis revealed that MCP-1 was expressed in endomyocardial biopsy samples obtained from HCM patients with systolic dysfunction. Furthermore, MCP-1 levels were inversely correlated with fractional shortening (r=-.401, P<.05) and correlated with left ventricular end-diastolic pressure (r=-.579, P<.01). CONCLUSION These results show that MCP-1 is associated with, and might be involved in the pathogenesis of, left ventricular systolic dysfunction in patients with HCM.
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Rodríguez JE, McCudden CR, Willis MS. Familial hypertrophic cardiomyopathy: basic concepts and future molecular diagnostics. Clin Biochem 2009; 42:755-65. [PMID: 19318019 DOI: 10.1016/j.clinbiochem.2009.01.020] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2008] [Revised: 01/24/2009] [Accepted: 01/28/2009] [Indexed: 11/26/2022]
Abstract
Familial hypertrophic cardiomyopathies (FHC) are the most common genetic heart diseases in the United States, affecting nearly 1 in 500 people. Manifesting as increased cardiac wall thickness, this autosomal dominant disease goes mainly unnoticed as most affected individuals are asymptomatic. Up to 1-2% of children and adolescents and 0.5-1% adults with FHC die of sudden cardiac death, making it critical to quickly and accurately diagnose FHC to institute therapy and potentially reduce mortality. However, due to the heterogeneity of the genetic defects in mainly sarcomere proteins, this is a daunting task even with current diagnostic methods. Exciting new methods utilizing high-throughput microarray technology to identify FHC mutations by a method known as array-based resequencing has recently been described. Additionally, next generation sequencing methodologies may aid in improving FHC diagnosis. In this review, we discuss FHC pathophysiology, the rationale for testing, and discuss the limitations and advantages of current and future diagnostics.
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Affiliation(s)
- Jessica E Rodríguez
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC 27599-7525, USA
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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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Graham-Cryan MA, Rowe G, Hathaway L, Biddle S, Tripodi D, Fananapazir L. Obstructive Hypertrophic Cardiomyopathy. ACTA ACUST UNITED AC 2008; 19:133-40. [PMID: 15539974 DOI: 10.1111/j.0889-7204.2003.03400.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Hypertrophic cardiomyopathy (HCM) is a primary disease of cardiac muscle characterized by a thickening of the left ventricular wall and often predominantly affecting the interventricular septum. This paper presents a case study of a 53-year-old female with a dynamic and obstructive form of HCM. The study includes a case presentation, clinical findings, investigations, and management. Patient findings were obtained before and after alcohol septal ablation, a novel interventional therapy. The article reviews the various forms of HCM and describes the currently available treatment modalities for obstructive HCM. Further research will be necessary to determine the comparative efficacy between past, present, and future therapies.
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Affiliation(s)
- Melissa A Graham-Cryan
- Cardiovascular Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, 10 Center Drive MSC 1650, Room 7B-15, Bethesda, MD 20892-1650, USA.
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Wang S, Zou Y, Fu C, Xu X, Wang J, Song L, Wang H, Chen J, Wang J, Huan T, Hui R. Worse prognosis with gene mutations of beta-myosin heavy chain than myosin-binding protein C in Chinese patients with hypertrophic cardiomyopathy. Clin Cardiol 2008; 31:114-8. [PMID: 18383048 DOI: 10.1002/clc.20151] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND No data are available on survival analysis and longitudinal evolution of patients with gene mutations of beta-myosin heavy chain (MYH7) and myosin binding protein C (MYBPC3) in Chinese. HYPOTHESIS To prospectively investigate whether different gene mutations confer distinct prognosis. METHODS We performed a prospective study in 70 HCM patients and 46 genetically affected family members without HCM-phenotype with direct DNA sequencing of MYH7 and MYBPC3, clinical assessments, and 5.8 +/- 1.8 years follow-up. RESULTS After follow-up, more surgical intervention (8/52 versus 0/18, p < 0.001), higher sudden death risk (7/52 versus 0/18, p < 0.001) and shorter life span were found in patients with MYH7 mutations than in patients with MYBPC3 mutations (45.1 +/- 14.0 versus 73.5 +/- 7.5 years, p = 0.03). Seven of the 27 mutation carriers of MYH7 had clinical presentations of HCM, but no carriers of MYBPC3 mutations developed to HCM during follow-up. Maximal wall thickness was thicker in the patients carrying mutations in the global region of MYH7 than in those carrying mutations in the rod region of MYH7 (21.5 +/- 6.6 versus 15 +/- 6.1 mm, p < 0.05) at baseline. More sudden death (7/41 versus 0/11) and left ventricular dysfunction (NYHA Class III approximately IV, 17/32 versus 1/10) were identified in patients with mutations in the global region of MYH7 than in patients with other mutations. CONCLUSIONS MYH7 mutations, especially in the global region, cause malignant clinical phenotypes.
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Affiliation(s)
- Shuxia Wang
- Department of Cardiology, Sino-German Laboratory for Molecular Medicine, Key Laboratory for Clinical Cardiovascular Genetics of Ministry of Education, Peking Union Medical College, Beijing, China
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Stravopodis DJ, Zapheiropoulos AZ, Voutsinas G, Margaritis LH, Papassideri IS. A PCR-based integrated protocol for the structural analysis of the 13th exon of the human beta-myosin heavy chain gene (MYH7): development of a diagnostic tool for HCM disease. Exp Mol Pathol 2008; 84:245-50. [PMID: 18499102 DOI: 10.1016/j.yexmp.2008.03.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2008] [Accepted: 03/26/2008] [Indexed: 10/22/2022]
Abstract
Familial Hypertrophic Cardiomyopathy (FHC) constitutes a genetic disease of the sarcomere characterized by a Mendelian pattern of inheritance. A variety of different mutations affecting the at least eight sarcomeric gene products has been identified and the majority of them appear to function through a dominant negative mechanism. Family history analysis and genetic counseling have been widely adopted as integral tools for the evaluation and management of individuals with Hypertrophic Cardiomyopathy (HCM). Genetic testing of the disease has been progressively released into the clinical mainstream, thus rendering the development of novel and potent molecular diagnostic protocols an inevitable task. To this direction, we have evolved an integrated PCR-based molecular protocol, which through the utilization of novel "exonic" primers allows, among others, the structural analysis of the 13th exon of the human beta-myosin heavy chain gene locus (MYH7) mainly characterized by the critical for HCM Arginine residue 403 (R(403)). Interestingly, through a DNA sequencing approach, a single nucleotide substitution from "G" to "T" was detected in the adjacent 13th intron, thus divulging the versatile potential of the present molecular protocol to clinical practice.
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Affiliation(s)
- Dimitrios J Stravopodis
- Faculty of Biology, Department of Cell Biology and Biophysics, University of Athens, Panepistimiopolis 15784, Zografou, Athens, Greece
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Abstract
PURPOSE OF REVIEW Cardiac hypertrophy is a common phenotypic response of the heart to stimulants. It is associated with increased morbidity and mortality in various cardiovascular disorders. Genetic factors are important determinants of phenotypic expression of cardiac hypertrophy, whether in single-gene disorders or in complex traits. We focus on the molecular genetics of cardiac hypertrophy in various conditions with an emphasis on hypertrophic cardiomyopathy, a genetic paradigm of cardiac hypertrophic response. RECENT FINDINGS The molecular genetic basis of cardiac hypertrophy in single-gene disorders has been partially elucidated. Likewise, the impact of genetics on the expression of cardiac hypertrophy in the general population has been demonstrated. Identification of mutations in the Z disk proteins has expanded the spectrum of causal mutations beyond the thin and thick filaments of the sarcomeres. In addition, modifier loci have been mapped and shown to impart considerable effects on the expression of cardiac hypertrophy in hypertrophic cardiomyopathy. Elucidation of the molecular genetics of sarcomeric hypertrophic cardiomyopathy and many of the phenocopies has highlighted the limitations of clinical diagnosis as a determinant of management and prognostic advice. The findings have raised the importance of diagnosis and treatment algorithms, which are based on both genotype and phenotype information. SUMMARY Cardiac hypertrophy, regardless of the cause, is the phenotypic consequence of complex interactions between genetic and nongenetic factors.
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Affiliation(s)
- Ali J Marian
- The Brown Foundation Institute of Molecular Medicine, Center for Cardiovascular Genetic Research, The University of Texas Health Science Center, Houston, Texas 77030, USA.
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Marian A. Utilities and limitations of genetic testing for hypertropic cardiomyopathy. EXPERT OPINION ON MEDICAL DIAGNOSTICS 2008; 2:539-46. [PMID: 23495742 DOI: 10.1517/17530059.2.5.539] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Hypertropic cardiomyopathy (HCM) is a primary disease of cardiac myocytes, diagnosed clinically by the presence of cardiac hypertrophy in the absence of any known cause. Over a dozen causal genes and several hundred mutations for HCM have been identified. OBJECTIVE The utilities of genetic testing in accurate diagnosis, prognostication and treatment of HCM are reviewed. METHODS The existing data are reviewed. RESULTS/CONCLUSIONS There is considerable interest in genetic testing for HCM. However, heterogeneity of the causal genes and alleles has hampered the efforts to develop a simple comprehensive genetic screening test. At present, it is feasible to screen for the 5 most common causal genes, which collectively account for ∼ 60% of the HCM. Advances of deep resequencing technologies are expected to increase the yield considerably and, hence, increase the use of genetic testing in clinical practice. However, the utility of genetic testing for risk stratification is expected to be limited, as factors other than the causal genes also contribute to the development of the phenotype. A comprehensive approach that includes the information content of the causal mutations, the modifier genes and the non-genetic factors will be necessary for accurate risk stratification and genetic-based interventions.
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Affiliation(s)
- Aj Marian
- The University of Texas Health Science Center, The Brown Foundation Institute of Molecular Medicine, Center for Cardiovascular Genetic Research, Texas Heart Institute at St Luke's Episcopal Hospital, 6770 Bertner Street, DAC 900A, Houston, TX 77030, USA +1 713 500 2350 ; +1 713 500 2320 ;
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Morita H, Rehm HL, Menesses A, McDonough B, Roberts AE, Kucherlapati R, Towbin JA, Seidman JG, Seidman CE. Shared genetic causes of cardiac hypertrophy in children and adults. N Engl J Med 2008; 358:1899-908. [PMID: 18403758 PMCID: PMC2752150 DOI: 10.1056/nejmoa075463] [Citation(s) in RCA: 289] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
BACKGROUND The childhood onset of idiopathic cardiac hypertrophy that occurs without a family history of cardiomyopathy can portend a poor prognosis. Despite morphologic similarities to genetic cardiomyopathies of adulthood, the contribution of genetics to childhood-onset hypertrophy is unknown. METHODS We assessed the family and medical histories of 84 children (63 boys and 21 girls) with idiopathic cardiac hypertrophy diagnosed before 15 years of age (mean [+/-SD] age, 6.99+/-6.12 years). We sequenced eight genes: MYH7, MYBPC3, TNNT2, TNNI3, TPM1, MYL3, MYL2, and ACTC. These genes encode sarcomere proteins that, when mutated, cause adult-onset cardiomyopathies. We also sequenced PRKAG2 and LAMP2, which encode metabolic proteins; mutations in these genes can cause early-onset ventricular hypertrophy. RESULTS We identified mutations in 25 of 51 affected children without family histories of cardiomyopathy and in 21 of 33 affected children with familial cardiomyopathy. Among 11 of the 25 children with presumed sporadic disease, 4 carried new mutations and 7 inherited the mutations. Mutations occurred predominantly (in >75% of the children) in MYH7 and MYBPC3; significantly more MYBPC3 missense mutations were detected than occur in adult-onset cardiomyopathy (P<0.005). Neither hypertrophic severity nor contractile function correlated with familial or genetic status. Cardiac transplantation and sudden death were more prevalent among mutation-positive than among mutation-negative children; implantable cardioverter-defibrillators were more frequent (P=0.007) in children with family histories that were positive for the mutation. CONCLUSIONS Genetic causes account for about half of presumed sporadic cases and nearly two thirds of familial cases of childhood-onset hypertrophy. Childhood-onset hypertrophy should prompt genetic analyses and family evaluations.
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Affiliation(s)
- Hiroyuki Morita
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
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Keren A, Syrris P, McKenna WJ. Hypertrophic cardiomyopathy: the genetic determinants of clinical disease expression. ACTA ACUST UNITED AC 2008; 5:158-68. [PMID: 18227814 DOI: 10.1038/ncpcardio1110] [Citation(s) in RCA: 148] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2007] [Accepted: 11/23/2007] [Indexed: 11/09/2022]
Abstract
Hypertrophic cardiomyopathy (HCM), defined clinically by the presence of unexplained left ventricular hypertrophy, is the most common inherited cardiac disorder. This condition is the major cause of sudden death in the young (<30 years of age) and in athletes. The clinical phenotype is heterogeneous, and mutations in a number of sarcomeric contractile-protein genes are responsible for causing the disease in approximately 60% of individuals with HCM. Other inherited syndromes, as well as metabolic and mitochondrial disorders, can present as clinical phenocopies and can be distinguished by their associated cardiac and noncardiac features and on the basis of their unique molecular genetics. The mode of inheritance, natural history and treatment of phenocopies can differ from those of HCM caused by mutations in sarcomere genes. Detailed clinical evaluation and mutation analysis are, therefore, important in providing an accurate diagnosis in order to enable genetic counseling, prognostic evaluation and appropriate clinical management. This Review summarizes current knowledge on the genetics, disease mechanisms, and correlations between phenotype and genotype in patients with HCM, and discusses the implications of genetic testing in routine clinical practice.
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Affiliation(s)
- Andre Keren
- Department of Cardiology, Hadassah University Hospital, Jerusalem, Israel
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Shimizu M, Ino H, Okeie K, Yamaguchi M, Nagata M, Hayashi K, Itoh H, Iwaki T, Oe K, Konno T, Mabuchi H. T-peak to T-end interval may be a better predictor of high-risk patients with hypertrophic cardiomyopathy associated with a cardiac troponin I mutation than QT dispersion. Clin Cardiol 2006; 25:335-9. [PMID: 12109867 PMCID: PMC6653869 DOI: 10.1002/clc.4950250706] [Citation(s) in RCA: 189] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
BACKGROUND Patients with hypertrophic cardiomyopathy (HCM) associated with a deletion of lysine 183 (K183del) in the cardiac troponin I (cTnI) gene suffer sudden cardiac death at all ages. However, the correlation between QT variables and sudden cardiac death in these patients remains uncertain. HYPOTHESIS We evaluated the correlation between QT variables and sudden cardiac death and/or ventricular tachyarrhythmia (SCD/VT) in patients with HCM associated with the cTnI mutation. METHODS We analyzed 10 probands with HCM associated with the cTnI gene K183del and their family members. The subjects were divided into three groups: Group A (n = 7), mutation carriers with SCD/VT; Group B (n = 16), mutation carriers without SCD/VT; Group C (n = 24), no mutation carriers. QT intervals were corrected using Bazett's formula. RESULTS Maximum QTc and corrected QT dispersion were significantly longer in Groups A and B than in Group C. However, there were no differences in either parameter between Groups A and B. On the contrary, the peak-to-end interval of T wave/QT interval in V5 (Tpe) in Group A was significantly longer than that in Groups B and C. Logistic regression analysis revealed that Tpe was a good clinical predictor for SCD/VT in patients with HCM in this study. CONCLUSIONS These results suggest that Tpe rather than QT dispersion may be one of the best predictors for SCD/VT in patients with HCM associated with the K183del mutation in the cTnI gene.
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Affiliation(s)
- Masami Shimizu
- Division of Cardiovascular Medicine, Graduate School of Medical Science, Kanazawa University, Japan.
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Hyun C, Filippich LJ. Molecular genetics of sudden cardiac death in small animals - a review. Vet J 2006; 171:39-50. [PMID: 16427581 DOI: 10.1016/j.tvjl.2004.10.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/08/2004] [Indexed: 10/25/2022]
Abstract
Sudden cardiac death in small animals is uncommon but often occurs due to cardiac conduction defects or myocardial diseases. Primary cardiac conduction defects are mainly caused by mutations in genes involved in impulse conduction processes (e.g., gap-junction genes and transcription factors) or repolarisation processes (e.g., ion-channel genes), whereas primary cardiomyopathies are mainly caused by defective force generation or force transmission due to gene mutations in either sarcomeric or cytoskeleton proteins. Although over 50 genes have been identified in humans directly or indirectly related to sudden cardiac death, no genetic aetiologies have been identified in small animals. Sudden cardiac deaths have been also reported in German Shepherds and Boxers. A better understanding of molecular genetic aetiologies for sudden cardiac death will be required for future study toward unveiling aetiology in sudden cardiac death in small animals.
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Affiliation(s)
- Changbaig Hyun
- Victor Chang Cardiac Research Institute, 384 Victoria Street, Darlinghurst, NSW 2010, Australia
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46
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Tardiff JC. Sarcomeric proteins and familial hypertrophic cardiomyopathy: linking mutations in structural proteins to complex cardiovascular phenotypes. Heart Fail Rev 2006; 10:237-48. [PMID: 16416046 DOI: 10.1007/s10741-005-5253-5] [Citation(s) in RCA: 146] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Hypertrophic Cardiomyopathy (HCM) is a relatively common primary cardiac disorder defined as the presence of a hypertrophied left ventricle in the absence of any other diagnosed etiology. HCM is the most common cause of sudden cardiac death in young people which often occurs without precedent symptoms. The overall clinical phenotype of patients with HCM is broad, ranging from a complete lack of cardiovascular symptoms to exertional dyspnea, chest pain, and sudden death, often due to arrhythmias. To date, 270 independent mutations in nine sarcomeric protein genes have been linked to Familial Hypertrophic Cardiomyopathy (FHC), thus the clinical variability is matched by significant genetic heterogeneity. While the final clinical phenotype in patients with FHC is a result of multiple factors including modifier genes, environmental influences and genotype, initial screening studies had suggested that individual gene mutations could be linked to specific prognoses. Given that the sarcomeric genes linked to FHC encode proteins with known functions, a vast array of biochemical, biophysical and physiologic experimental approaches have been applied to elucidate the molecular mechanisms that underlie the pathogenesis of this complex cardiovascular disorder. In this review, to illustrate the basic relationship between protein dysfunction and disease pathogenesis we focus on representative gene mutations from each of the major structural components of the cardiac sarcomere: the thick filament (beta MyHC), the thin filament (cTnT and Tm) and associated proteins (MyBP-C). The results of these studies will lead to a better understanding of FHC and eventually identify targets for therapeutic intervention.
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Affiliation(s)
- Jil C Tardiff
- Department of Physiology and Biophysics and the Department of Medicine (Cardiology), Albert Einstein College of Medicine, Bronx, NY 10461, USA.
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Abstract
Cardiomyopathies are primary disorders of cardiac muscle associated with abnormalities of cardiac wall thickness, chamber size, contraction, relaxation, conduction, and rhythm. They are a major cause of morbidity and mortality at all ages and, like acquired forms of cardiovascular disease, often result in heart failure. Over the past two decades, molecular genetic studies of humans and analyses of model organisms have made remarkable progress in defining the pathogenesis of cardiomyopathies. Hypertrophic cardiomyopathy can result from mutations in 11 genes that encode sarcomere proteins, and dilated cardiomyopathy is caused by mutations at 25 chromosome loci where genes encoding contractile, cytoskeletal, and calcium regulatory proteins have been identified. Causes of cardiomyopathies associated with clinically important cardiac arrhythmias have also been discovered: Mutations in cardiac metabolic genes cause hypertrophy in association with ventricular pre-excitation and mutations causing arrhythmogenic right ventricular dysplasia were recently discovered in protein constituents of desmosomes. This considerable genetic heterogeneity suggests that there are multiple pathways that lead to changes in heart structure and function. Defects in myocyte force generation, force transmission, and calcium homeostasis have emerged as particularly critical signals driving these pathologies. Delineation of the cell and molecular events triggered by cardiomyopathy gene mutations provide new fundamental knowledge about myocyte biology and organ physiology that accounts for cardiac remodeling and defines mechanistic pathways that lead to heart failure.
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Affiliation(s)
- Ferhaan Ahmad
- Cardiovascular Institute and Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, USA
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48
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Zen K, Irie H, Doue T, Takamiya M, Yamano T, Sawada T, Azuma A, Matsubara H. Analysis of circulating apoptosis mediators and proinflammatory cytokines in patients with idiopathic hypertrophic cardiomyopathy: comparison between nonobstructive and dilated-phase hypertrophic cardiomyopathy. Int Heart J 2005; 46:231-44. [PMID: 15876807 DOI: 10.1536/ihj.46.231] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
We examined the plasma levels of soluble Fas (sFas) or Fas ligand (sFas-L), tumor necrosis factor-alpha (TNF-alpha), and interleukin-6 (IL-6) in patients with idiopathic nonobstructive (HNCM) and dilated-phase (DHCM) hypertrophic cardiomyopathy. Patients with idiopathic hypertrophic cardiomyopathy (HCM) may deteriorate to DHCM and the pathogenesis is unknown. The levels of these plasma cytokines were measured by ELISA and echocardiography was performed in 38 HNCM and 11 DHCM patients, and 10 normal subjects. The follow-up period was three years. In HNCM, TNF-alpha (43.3 +/- 45.2 versus 16.9 +/- 4.3 pg/mL) and IL-6 (65.1 +/- 86.4 versus 4.0 +/- 2.1 pg/mL) were slightly higher compared to normal subjects and sFas (3.7 +/- 1.2 versus 2.1 +/- 0.7 ng/mL) increased significantly. sFas (3.9 +/- 1.8), TNF-alpha (79.3 +/- 72.4), and IL-6 (234.1 +/- 135.2) in DHCM were significantly increased and only IL-6 was significantly different from HNCM. sFas-L (0.18 +/- 0.08 versus 0.25 +/- 0.05 ng/mL) in HNCM was significantly decreased, and the decrease was marked in DHCM (0.05 +/- 0.02). In HNCM, TNF-alpha was negatively correlated with fractional shortening (r = -0.432, P = 0.0062) or positively with IL-6 (r = 0.665, P < 0.0001), while sFas-L was negatively correlated with IL-6 (r = -0.580, P < 0.0001). DHCM with high sFas had significantly higher cumulative incidences of worsening heart failure. The Fas/Fas-L system and proinflammatory cytokines may play an important role in the status of HCM and its progression to DHCM.
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Affiliation(s)
- Kan Zen
- Department of Cardiovascular Medicine, Kyoto Prefectural University of Medicine, Agaru, Kyoto, Japan
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Nakamura K, Kusano KF, Matsubara H, Nakamura Y, Miura A, Nishii N, Banba K, Nagase S, Miyaji K, Morita H, Saito H, Emori T, Ohe T. Relationship between oxidative stress and systolic dysfunction in patients with hypertrophic cardiomyopathy. J Card Fail 2005; 11:117-23. [PMID: 15732031 DOI: 10.1016/j.cardfail.2004.05.005] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND Progression of hypertrophic cardiomyopathy (HCM) to left ventricular dilatation and systolic dysfunction sometimes occurs. However, the mechanism is not known. We examined whether oxidative stress was elevated in myocardia of HCM patients and whether the levels were correlated with left ventricular dilatation and systolic dysfunction. METHODS AND RESULTS Endomyocardial biopsy samples obtained from the right ventricular side of the septum of 31 patients with HCM, and 10 control subjects were studied immunohistochemically for the expression of 4-hydroxy-2-nonenal (HNE)-modified protein, which is a major lipid peroxidation product. Expression of HNE-modified protein was found in all myocardial biopsy samples from patients with HCM. Expression was distinct in the cytosol of cardiomyocytes. The expression levels in patients with HCM were significantly increased compared with those in control subjects (P = .0005). The expression levels in patients with HCM were correlated with left ventricular end-diastolic diameter (r = 0.483, P = .0053) and end-systolic diameter (r = 0.500, P = .0037) determined by echocardiography. The expression levels were inversely correlated with left ventricular ejection fraction determined by left ventriculography (r = -0.640, P = .0001). CONCLUSION Oxidative stress was elevated in myocardia of HCM patients and the levels were correlated with left ventricular dilatation and systolic dysfunction. Oxidative stress is involved in the pathogenesis of heart failure in patients with HCM.
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Affiliation(s)
- Kazufumi Nakamura
- Department of Cardiovascular Medicine, Okayama University Graduate School of Medicine and Dentistry, Okayama, Japan
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Abstract
This article outlines the up-to-date understanding of the molecular basis of disorders that cause sudden death. Several arrhythmic disorders that cause sudden death have been well-described at the molecular level, including the long QT syndromes and Brugada syndrome; this article reviews the current scientific knowledge of these diseases. Hypertrophic cardiomyopathy, a myocardial disorder that causes sudden death also has been well-studied. Finally, a disorder in which myocardial abnormalities and rhythm abnormalities coexist, arrhythmogenic right ventricular dysplasia, is described.
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MESH Headings
- Arrhythmias, Cardiac/genetics
- Arrhythmias, Cardiac/physiopathology
- Arrhythmogenic Right Ventricular Dysplasia/genetics
- Arrhythmogenic Right Ventricular Dysplasia/physiopathology
- Cardiomyopathy, Hypertrophic, Familial/genetics
- Cardiomyopathy, Hypertrophic, Familial/physiopathology
- Child
- Death, Sudden, Cardiac/etiology
- ERG1 Potassium Channel
- Ether-A-Go-Go Potassium Channels
- Humans
- KCNQ Potassium Channels
- KCNQ1 Potassium Channel
- Long QT Syndrome/complications
- Long QT Syndrome/genetics
- Long QT Syndrome/therapy
- NAV1.5 Voltage-Gated Sodium Channel
- Potassium Channels/physiology
- Potassium Channels, Voltage-Gated
- Sodium Channels/physiology
- Syndrome
- Tachycardia, Ventricular/genetics
- Wolff-Parkinson-White Syndrome/physiopathology
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Affiliation(s)
- Jeffrey A Towbin
- Department of Pediatrics (Cardiology), Texas Children's Hospital and Baylor College of Medicine, 6621 Fannin Street, FC. 430.09, Houston, TX 77030, USA.
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