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Shetty NS, Gaonkar M, Pampana A, Patel N, Li P, Arora G, Arora P. Titin truncating variants, cardiovascular risk factors and the risk of atrial fibrillation and heart failure. NATURE CARDIOVASCULAR RESEARCH 2024; 3:899-906. [PMID: 39196037 DOI: 10.1038/s44161-024-00511-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2024] [Accepted: 06/20/2024] [Indexed: 08/29/2024]
Abstract
High-proportion spliced-in (hiPSI) titin truncating variant (TTNtv) carriers have a higher risk of atrial fibrillation and heart failure1. However, the role of cardiovascular risk factors in modifying the risk of atrial fibrillation and heart failure attributed to hiPSI TTNtv carriers is unknown. Here, we investigate the role of cardiovascular risk, quantified using the pooled cohort equations (PCEs), in influencing the hazard of outcomes attributed to hiPSI TTNtvs among UK Biobank participants without baseline cardiovascular disease. The cohort was stratified based on hiPSI TTNtv carrier status and cardiovascular risk (low: <5%, intermediate: 5.0-7.5% and high: >7.5%). The primary outcome was a composite of atrial fibrillation, heart failure or death. TTNtv noncarriers with low cardiovascular risk were used as the reference group for all analyses. Among 179,752 participants (median age: 56 (49, 62) years; 57.5% female), the risk of the primary outcome was lower in hiPSI TTNtv carriers with low cardiovascular risk (adjusted hazard ratio: 2.23 (95% confidence interval: 1.62-3.07)) than those with high cardiovascular risk (adjusted hazard ratio: 8.21 (95% confidence interval: 6.63-10.18)). A favorable cardiovascular risk factor profile may partially offset the risk of clinical outcomes among hiPSI TTNtv carriers.
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Affiliation(s)
- Naman S Shetty
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - Mokshad Gaonkar
- Division of Cardiovascular Disease, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Akhil Pampana
- Division of Cardiovascular Disease, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Nirav Patel
- Division of Cardiovascular Disease, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Peng Li
- School of Nursing, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Garima Arora
- Division of Cardiovascular Disease, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Pankaj Arora
- Division of Cardiovascular Disease, University of Alabama at Birmingham, Birmingham, AL, USA.
- Section of Cardiology, Birmingham Veterans Affairs Medical Center, Birmingham, AL, USA.
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2
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Jolfayi AG, Kohansal E, Ghasemi S, Naderi N, Hesami M, MozafaryBazargany M, Moghadam MH, Fazelifar AF, Maleki M, Kalayinia S. Exploring TTN variants as genetic insights into cardiomyopathy pathogenesis and potential emerging clues to molecular mechanisms in cardiomyopathies. Sci Rep 2024; 14:5313. [PMID: 38438525 PMCID: PMC10912352 DOI: 10.1038/s41598-024-56154-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 03/01/2024] [Indexed: 03/06/2024] Open
Abstract
The giant protein titin (TTN) is a sarcomeric protein that forms the myofibrillar backbone for the components of the contractile machinery which plays a crucial role in muscle disorders and cardiomyopathies. Diagnosing TTN pathogenic variants has important implications for patient management and genetic counseling. Genetic testing for TTN variants can help identify individuals at risk for developing cardiomyopathies, allowing for early intervention and personalized treatment strategies. Furthermore, identifying TTN variants can inform prognosis and guide therapeutic decisions. Deciphering the intricate genotype-phenotype correlations between TTN variants and their pathologic traits in cardiomyopathies is imperative for gene-based diagnosis, risk assessment, and personalized clinical management. With the increasing use of next-generation sequencing (NGS), a high number of variants in the TTN gene have been detected in patients with cardiomyopathies. However, not all TTN variants detected in cardiomyopathy cohorts can be assumed to be disease-causing. The interpretation of TTN variants remains challenging due to high background population variation. This narrative review aimed to comprehensively summarize current evidence on TTN variants identified in published cardiomyopathy studies and determine which specific variants are likely pathogenic contributors to cardiomyopathy development.
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Affiliation(s)
- Amir Ghaffari Jolfayi
- Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Erfan Kohansal
- Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Serwa Ghasemi
- Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Niloofar Naderi
- Cardiogenetic Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Mahshid Hesami
- Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | | | - Maryam Hosseini Moghadam
- Cardiogenetic Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Amir Farjam Fazelifar
- Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Majid Maleki
- Cardiogenetic Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Samira Kalayinia
- Cardiogenetic Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran.
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Shetty NS, Pampana A, Patel N, Li P, Arora G, Arora P. High-proportion spliced-in titin truncating variants in African and European ancestry in the All of Us Research Program. NATURE CARDIOVASCULAR RESEARCH 2024; 3:140-144. [PMID: 39196186 DOI: 10.1038/s44161-023-00417-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 12/15/2023] [Indexed: 08/29/2024]
Abstract
High-proportion spliced-in titin truncating variants (hiPSI TTNtvs) have been associated with an increased risk of atrial fibrillation, dilated cardiomyopathy (DCM) and heart failure in individuals of European ancestry1. However, similar data in individuals of African ancestry are lacking. Here we examined the association of hiPSI TTNtvs with atrial fibrillation, DCM and heart failure in individuals of African ancestry using data from the All of Us Research Program. Among 38,154 individuals of African ancestry, 169 (0.4%) individuals carried a hiPSI TTNtv. hiPSI TTNtv carriers were at a higher risk of developing atrial fibrillation (adjusted hazard ratio (HRadj) 2.42, 95% confidence interval (CI) 1.52-3.85), DCM (HRadj 2.82, 95% CI 1.81-4.39) and heart failure (HRadj 2.07, 95% CI 1.43-3.00) compared with noncarriers. The association of hiPSI TTNtvs with atrial fibrillation, DCM and heart failure was similar in individuals of African ancestry and those of European ancestry. Therefore, genetic testing for hiPSI TTNtvs may permit early identification of carriers and support preventive measures to reduce the likelihood of heart failure development both in individuals of European ancestry and in individuals of African ancestry.
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Affiliation(s)
- Naman S Shetty
- Division of Cardiovascular Disease, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Akhil Pampana
- Division of Cardiovascular Disease, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Nirav Patel
- Division of Cardiovascular Disease, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Peng Li
- School of Nursing, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Garima Arora
- Division of Cardiovascular Disease, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Pankaj Arora
- Division of Cardiovascular Disease, University of Alabama at Birmingham, Birmingham, AL, USA.
- Section of Cardiology, Birmingham Veterans Affairs Medical Center, Birmingham, AL, USA.
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DePaolo J, Bornstein M, Judy R, Abramowitz S, Verma SS, Levin MG, Arany Z, Damrauer SM. Titin-Truncating variants Predispose to Dilated Cardiomyopathy in Diverse Populations. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.01.17.24301405. [PMID: 38293092 PMCID: PMC10827233 DOI: 10.1101/2024.01.17.24301405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Importance The effect of high percentage spliced in (hiPSI) TTN truncating variants (TTNtvs) on risk of dilated cardiomyopathy (DCM) has historically been studied among population subgroups defined by genetic similarity to European reference populations. This has raised questions about the effect of TTNtvs in diverse populations, especially among individuals genetically similar to African reference populations. Objective To determine the effect of TTNtvs on risk of DCM in diverse population as measured by genetic distance (GD) in principal component (PC) space. Design Cohort study. Setting Penn Medicine Biobank (PMBB) is a large, diverse biobank. Participants Participants were recruited from across the Penn Medicine healthcare system and volunteered to have their electronic health records linked to biospecimen data including DNA which has undergone whole exome sequencing. Main Outcomes and Measures Risk of DCM among individuals carrying a hiPSI TTNtv. Results Carrying a hiPSI TTNtv was associated with DCM among PMBB participants across a range of GD deciles from the 1000G European centroid; the effect estimates ranged from odds ratio (OR) = 3.29 (95% confidence interval [CI] 1.26 to 8.56) to OR = 9.39 (95% CI 3.82 to 23.13). When individuals were assigned to population subgroups based on genetic similarity to the 1000G reference populations, hiPSI TTNtvs conferred significant risk of DCM among those genetically similar to the 1000G European reference population (OR = 7.55, 95% CI 4.99 to 11.42, P<0.001) and individuals genetically similar to the 1000G African reference population (OR 3.50, 95% CI 1.48 to 8.24, P=0.004). Conclusions and Relevance TTNtvs are associated with increased risk of DCM among a diverse cohort. There is no significant difference in effect of TTNtvs on DCM risk across deciles of GD from the 1000G European centroid, suggesting genetic background should not be considered when screening individuals for titin-related DCM.
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Affiliation(s)
- John DePaolo
- Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Marc Bornstein
- Cardiovascular Institute, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, PA 19104, USA
| | - Renae Judy
- Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Sarah Abramowitz
- Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Shefali S Verma
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, PA 19104, USA
| | - Michael G Levin
- Cardiovascular Institute, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, PA 19104, USA
- Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA 19104, USA
| | - Zoltan Arany
- Cardiovascular Institute, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, PA 19104, USA
| | - Scott M Damrauer
- Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Cardiovascular Institute, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, PA 19104, USA
- Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA 19104, USA
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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Akinrinade O, Lesurf R, Lougheed J, Mondal T, Smythe J, Altamirano-Diaz L, Oechslin E, Mital S. Age and Sex Differences in the Genetics of Cardiomyopathy. J Cardiovasc Transl Res 2023; 16:1287-1302. [PMID: 37477868 PMCID: PMC10721711 DOI: 10.1007/s12265-023-10411-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Accepted: 07/04/2023] [Indexed: 07/22/2023]
Abstract
Cardiomyopathy has variable penetrance. We analyzed age and sex-related genetic differences in 1,397 cardiomyopathy patients (Ontario, UK) with whole genome sequencing. Pediatric cases (n = 471) harbored more deleterious protein-coding variants in Tier 1 cardiomyopathy genes compared to adults (n = 926) (34.6% vs 25.9% respectively, p = 0.0015), with variant enrichment in constrained coding regions. Pediatric patients had a higher burden of sarcomere and lower burden of channelopathy gene variants compared to adults. Specifically, pediatric patients had more MYH7 and MYL3 variants in hypertrophic cardiomyopathy, and fewer TTN truncating variants in dilated cardiomyopathy. MYH7 variants clustered in the myosin head and neck domains in children. OBSCN was a top mutated gene in adults, enriched for protein-truncating variants. In dilated cardiomyopathy, female patients had a higher burden of z-disc gene variants compared to males. Genetic differences may explain age and sex-related variability in cardiomyopathy penetrance. Genotype-guided predictions of age of onset can inform pre-test genetic counseling. Pediatric cardiomyopathy patients were more likely to be genotype-positive than adults with a higher burden of variants in MYH7, MYL3, TNNT2, VCL. Adults had a higher burden of OBSCN and TTN variants. Females with dilated cardiomyopathy (DCM) had a higher burden of z-disc gene variants compared to males.
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Affiliation(s)
- Oyediran Akinrinade
- Genetics and Genome Biology Program, The Hospital for Sick Children, 555 University Avenue, Toronto, ON, M5G 1X8, Canada
- St. George's University School of Medicine, St. George's, West Indies, Grenada
| | - Robert Lesurf
- Genetics and Genome Biology Program, The Hospital for Sick Children, 555 University Avenue, Toronto, ON, M5G 1X8, Canada
| | - Jane Lougheed
- Division of Cardiology, Children's Hospital of Eastern Ontario, Ottawa, ON, Canada
| | - Tapas Mondal
- Division of Cardiology, Department of Pediatrics, McMaster Children's Hospital, Hamilton, ON, Canada
| | - John Smythe
- Division of Cardiology, Department of Pediatrics, Kingston General Hospital, Kingston, ON, Canada
| | - Luis Altamirano-Diaz
- Division of Cardiology, Department of Pediatrics, London Health Sciences Centre, London, ON, Canada
| | - Erwin Oechslin
- Division of Cardiology, Toronto Adult Congenital Heart Disease Program at Peter Munk Cardiac Centre, Department of Medicine, University Health Network, and University of Toronto, Toronto, ON, Canada
| | - Seema Mital
- Genetics and Genome Biology Program, The Hospital for Sick Children, 555 University Avenue, Toronto, ON, M5G 1X8, Canada.
- Ted Rogers Centre for Heart Research, Toronto, ON, Canada.
- Division of Cardiology, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada.
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Fleming JR, Müller I, Zacharchenko T, Diederichs K, Mayans O. Molecular insights into titin's A-band. J Muscle Res Cell Motil 2023; 44:255-270. [PMID: 37258982 PMCID: PMC10665226 DOI: 10.1007/s10974-023-09649-1] [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: 03/06/2023] [Accepted: 04/11/2023] [Indexed: 06/02/2023]
Abstract
The thick filament-associated A-band region of titin is a highly repetitive component of the titin chain with important scaffolding properties that support thick filament assembly. It also has a demonstrated link to human disease. Despite its functional significance, it remains a largely uncharacterized part of the titin protein. Here, we have performed an analysis of sequence and structure conservation of A-band titin, with emphasis on poly-FnIII tandem components. Specifically, we have applied multi-dimensional sequence pairwise similarity analysis to FnIII domains and complemented this with the crystallographic elucidation of the 3D-structure of the FnIII-triplet A84-A86 from the fourth long super-repeat in the C-zone (C4). Structural models serve here as templates to map sequence conservation onto super-repeat C4, which we show is a prototypical representative of titin's C-zone. This templating identifies positionally conserved residue clusters in C super-repeats with the potential of mediating interactions to thick-filament components. Conservation localizes to two super-repeat positions: Ig domains in position 1 and FnIII domains in position 7. The analysis also allows conclusions to be drawn on the conserved architecture of titin's A-band, as well as revisiting and expanding the evolutionary model of titin's A-band.
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Affiliation(s)
| | - Iljas Müller
- Department of Biology, University of Konstanz, 78457, Konstanz, Germany
| | - Thomas Zacharchenko
- Institute of Integrative Biology, University of Liverpool, Liverpool, L69 7ZB, UK
- Wellcome Centre for Cell-Matrix Research, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK
| | - Kay Diederichs
- Department of Biology, University of Konstanz, 78457, Konstanz, Germany
| | - Olga Mayans
- Department of Biology, University of Konstanz, 78457, Konstanz, Germany.
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Kim YG, Ha C, Shin S, Park JH, Jang JH, Kim JW. Enrichment of titin-truncating variants in exon 327 in dilated cardiomyopathy and its relevance to reduced nonsense-mediated mRNA decay efficiency. Front Genet 2023; 13:1087359. [PMID: 36685919 PMCID: PMC9845391 DOI: 10.3389/fgene.2022.1087359] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 12/07/2022] [Indexed: 01/05/2023] Open
Abstract
Titin truncating variants (TTNtvs) are the most common genetic cause of dilated cardiomyopathy (DCM). Among four regions of titin, A-band enrichment of DCM-causing TTNtvs is widely accepted but the underlying mechanism is still unknown. Meanwhile, few reports have identified exon 327 as a highly mutated A-band exon but the degree of exon 327 enrichment has not been quantitatively investigated. To find the real hotspot of DCM-causing TTNtvs, we aimed to reassess the degree of TTNtv enrichment in known titin regions and in exon 327, separately. In addition, we tried to explain exon 327 clustering in terms of nonsense-mediated mRNA decay (NMD) efficiency and a dominant negative mechanism recently proposed. Research papers focusing on TTNtvs found in patients with DCM were collected. A total of 612 patients with TTNtv-realated DCM were obtained from 10 studies. In the four regions of TTN and exon 327, the degree of TTNtvs enrichment was calculated in a way that the effect of distribution of highly expressed exons was normalized. As a result, exon 327 was the only region that showed significant enrichment for DCM-related TTNtv (p < .001). On the other hand, other A-band exons had almost the same number of TTNtv of random distribution. A review of RNAseq data revealed that the median allelic imbalance deviation of exon 327 TTNtvs was .04, indicating almost zero NMD. From these findings, we propose that the widely accepted A-band enrichment of DCM-related TTNtv is mostly attributable to exon 327 enrichment. In addition, based on the recently demonstrated dominant negative mechanism, the extremely low NMD efficiency seems to contribute to exon 327 enrichment.
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Affiliation(s)
- Young-gon Kim
- Samsung Medical Center, Department of Laboratory Medicine and Genetics, Sungkyunkwan University School of Medicine, Seoul, South Korea
| | - Changhee Ha
- Samsung Medical Center, Department of Laboratory Medicine and Genetics, Sungkyunkwan University School of Medicine, Seoul, South Korea
| | - Sunghwan Shin
- Samsung Medical Center, Department of Laboratory Medicine and Genetics, Sungkyunkwan University School of Medicine, Seoul, South Korea
| | - Jong-ho Park
- Clinical Genomics Center, Samsung Medical Center, Seoul, South Korea
| | - Ja-Hyun Jang
- Samsung Medical Center, Department of Laboratory Medicine and Genetics, Sungkyunkwan University School of Medicine, Seoul, South Korea
| | - Jong-Won Kim
- Samsung Medical Center, Department of Laboratory Medicine and Genetics, Sungkyunkwan University School of Medicine, Seoul, South Korea,Clinical Genomics Center, Samsung Medical Center, Seoul, South Korea,*Correspondence: Jong-Won Kim,
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8
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Parker LE, Landstrom AP. The clinical utility of pediatric cardiomyopathy genetic testing: From diagnosis to a precision medicine-based approach to care. PROGRESS IN PEDIATRIC CARDIOLOGY 2021; 62. [PMID: 34776723 DOI: 10.1016/j.ppedcard.2021.101413] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Background Pediatric-onset cardiomyopathies are rare yet cause significant morbidity and mortality in affected children. Genetic testing has a major role in the clinical evaluation of pediatric-onset cardiomyopathies, and identification of a variant in an associated gene can be used to confirm the clinical diagnosis and exclude syndromic causes that may warrant different treatment strategies. Further, risk-predictive testing of first-degree relatives can assess who is at-risk of disease and requires continued clinical follow-up. Aim of Review In this review, we seek to describe the current role of genetic testing in the clinical diagnosis and management of patients and families with the five major cardiomyopathies. Further, we highlight the ongoing development of precision-based approaches to diagnosis, prognosis, and treatment. Key Scientific Concepts of Review Emerging application of genotype-phenotype correlations opens the door for genetics to guide a precision medicine-based approach to prognosis and potentially for therapies. Despite advances in our understanding of the genetic etiology of cardiomyopathy and increased accessibility of clinical genetic testing, not all pediatric cardiomyopathy patients have a clear genetic explanation for their disease. Expanded genomic studies are needed to understand the cause of disease in these patients, improve variant classification and genotype-driven prognostic predictions, and ultimately develop truly disease preventing treatment.
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Affiliation(s)
- Lauren E Parker
- Department of Pediatrics, Division of Cardiology, Duke University School of Medicine, Durham, NC, United States
| | - Andrew P Landstrom
- Department of Pediatrics, Division of Cardiology, Duke University School of Medicine, Durham, NC, United States.,Department of Cell Biology, Duke University School of Medicine, Durham, NC, United States
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Crocini C, Gotthardt M. Cardiac sarcomere mechanics in health and disease. Biophys Rev 2021; 13:637-652. [PMID: 34745372 PMCID: PMC8553709 DOI: 10.1007/s12551-021-00840-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 08/27/2021] [Indexed: 12/23/2022] Open
Abstract
The sarcomere is the fundamental structural and functional unit of striated muscle and is directly responsible for most of its mechanical properties. The sarcomere generates active or contractile forces and determines the passive or elastic properties of striated muscle. In the heart, mutations in sarcomeric proteins are responsible for the majority of genetically inherited cardiomyopathies. Here, we review the major determinants of cardiac sarcomere mechanics including the key structural components that contribute to active and passive tension. We dissect the molecular and structural basis of active force generation, including sarcomere composition, structure, activation, and relaxation. We then explore the giant sarcomere-resident protein titin, the major contributor to cardiac passive tension. We discuss sarcomere dynamics exemplified by the regulation of titin-based stiffness and the titin life cycle. Finally, we provide an overview of therapeutic strategies that target the sarcomere to improve cardiac contraction and filling.
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Affiliation(s)
- Claudia Crocini
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Neuromuscular and Cardiovascular Cell Biology, Berlin, Germany
- German Center for Cardiovascular Research (DZHK) Partner Site Berlin, Berlin, Germany
- BioFrontiers Institute & Department of Molecular and Cellular Development, University of Colorado Boulder, Boulder, USA
| | - Michael Gotthardt
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Neuromuscular and Cardiovascular Cell Biology, Berlin, Germany
- German Center for Cardiovascular Research (DZHK) Partner Site Berlin, Berlin, Germany
- Charité-Universitätsmedizin Berlin, 10117 Berlin, Germany
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Hershberger RE, Cowan J, Jordan E, Kinnamon DD. The Complex and Diverse Genetic Architecture of Dilated Cardiomyopathy. Circ Res 2021; 128:1514-1532. [PMID: 33983834 DOI: 10.1161/circresaha.121.318157] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Our insight into the diverse and complex nature of dilated cardiomyopathy (DCM) genetic architecture continues to evolve rapidly. The foundations of DCM genetics rest on marked locus and allelic heterogeneity. While DCM exhibits a Mendelian, monogenic architecture in some families, preliminary data from our studies and others suggests that at least 20% to 30% of DCM may have an oligogenic basis, meaning that multiple rare variants from different, unlinked loci, determine the DCM phenotype. It is also likely that low-frequency and common genetic variation contribute to DCM complexity, but neither has been examined within a rare variant context. Other types of genetic variation are also likely relevant for DCM, along with gene-by-environment interaction, now established for alcohol- and chemotherapy-related DCM. Collectively, this suggests that the genetic architecture of DCM is broader in scope and more complex than previously understood. All of this elevates the impact of DCM genetics research, as greater insight into the causes of DCM can lead to interventions to mitigate or even prevent it and thus avoid the morbid and mortal scourge of human heart failure.
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Affiliation(s)
- Ray E Hershberger
- Divisions of Cardiovascular Medicine (R.E.H.), The Ohio State University Wexner Medical Center, Columbus.,Human Genetics (R.E.H., J.C., E.J., D.D.K.), The Ohio State University Wexner Medical Center, Columbus.,Department of Internal Medicine and the Davis Heart and Lung Research Institute (R.E.H., J.C., E.J., D.D.K.), The Ohio State University Wexner Medical Center, Columbus
| | - Jason Cowan
- Human Genetics (R.E.H., J.C., E.J., D.D.K.), The Ohio State University Wexner Medical Center, Columbus.,Department of Internal Medicine and the Davis Heart and Lung Research Institute (R.E.H., J.C., E.J., D.D.K.), The Ohio State University Wexner Medical Center, Columbus
| | - Elizabeth Jordan
- Human Genetics (R.E.H., J.C., E.J., D.D.K.), The Ohio State University Wexner Medical Center, Columbus.,Department of Internal Medicine and the Davis Heart and Lung Research Institute (R.E.H., J.C., E.J., D.D.K.), The Ohio State University Wexner Medical Center, Columbus
| | - Daniel D Kinnamon
- Human Genetics (R.E.H., J.C., E.J., D.D.K.), The Ohio State University Wexner Medical Center, Columbus.,Department of Internal Medicine and the Davis Heart and Lung Research Institute (R.E.H., J.C., E.J., D.D.K.), The Ohio State University Wexner Medical Center, Columbus
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11
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Xiao L, Li C, Sun Y, Chen Y, Wei H, Hu D, Yu T, Li X, Jin L, Shi L, Marian AJ, Wang DW. Clinical Significance of Variants in the TTN Gene in a Large Cohort of Patients With Sporadic Dilated Cardiomyopathy. Front Cardiovasc Med 2021; 8:657689. [PMID: 33996946 PMCID: PMC8120103 DOI: 10.3389/fcvm.2021.657689] [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: 01/23/2021] [Accepted: 03/05/2021] [Indexed: 12/11/2022] Open
Abstract
Background: Mutations in the TTN gene are the most common causes of dilated cardiomyopathy (DCM). The clinical significance of TTN gene variants remains inadequately understood. Methods: Whole-exome sequencing and phenotypic characterisation were performed, and patients were followed up for a median of 44 months. Results: We analyzed the association of the TTN variants with the clinical outcomes in a prospective study of 1,041 patients with sporadic DCM. TTN truncating variants (tTTN) were detected in 120 (11.5%) patients as compared with 2.4/10,000 East Asian populations in the Genome Aggregation Database (GnomAD; p < 0.0001). Pathogenic TTN missense variants were also enriched in DCM as compared with the GnomAD populations (27.6 vs. 5.9%, p < 0.0001). DCM patients with tTTN had a lower left ventricular ejection fraction (28.89 ± 8.72 vs. 31.81 ± 9.97, p = 0.002) and a lower frequency of the left bundle branch block (3.3 vs. 11.3%, p = 0.011) than those without or with mutations in other known causal genes (OCG). However, tTTN were not associated with the composite primary endpoint of cardiac death and heart transplantation during the follow-up period [adjusted hazard ratio (HR): 0.912; 95% confidence interval: 0.464–1.793; p = 0.790]. There was also no sex-dependent effect. Concomitant tTTN and pathogenic variants in OCG were present in only eight DCM patients and did not affect the outcome. Conclusion: The phenotype of DCM caused by tTTN, major causes of sporadic DCM, is not distinctly different from those caused by other causal genes for DCM.
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Affiliation(s)
- Lei Xiao
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Hubei Key Laboratory of Genetics and Molecular Mechanism of Cardiologic Disorders, Huazhong University of Science and Technology, Wuhan, China
| | - Chenze Li
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Hubei Key Laboratory of Genetics and Molecular Mechanism of Cardiologic Disorders, Huazhong University of Science and Technology, Wuhan, China
| | - Yang Sun
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Hubei Key Laboratory of Genetics and Molecular Mechanism of Cardiologic Disorders, Huazhong University of Science and Technology, Wuhan, China
| | - Yanghui Chen
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Hubei Key Laboratory of Genetics and Molecular Mechanism of Cardiologic Disorders, Huazhong University of Science and Technology, Wuhan, China
| | - Haoran Wei
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Hubei Key Laboratory of Genetics and Molecular Mechanism of Cardiologic Disorders, Huazhong University of Science and Technology, Wuhan, China
| | - Dong Hu
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Hubei Key Laboratory of Genetics and Molecular Mechanism of Cardiologic Disorders, Huazhong University of Science and Technology, Wuhan, China
| | - Ting Yu
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Hubei Key Laboratory of Genetics and Molecular Mechanism of Cardiologic Disorders, Huazhong University of Science and Technology, Wuhan, China
| | - Xianqing Li
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Hubei Key Laboratory of Genetics and Molecular Mechanism of Cardiologic Disorders, Huazhong University of Science and Technology, Wuhan, China
| | - Li Jin
- Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China
| | - Leming Shi
- Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China
| | - Ali J Marian
- Center for Cardiovascular Genetics, Houston, TX, United States
| | - Dao Wen Wang
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Hubei Key Laboratory of Genetics and Molecular Mechanism of Cardiologic Disorders, Huazhong University of Science and Technology, Wuhan, China.,Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China
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12
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Santiago CF, Huttner IG, Fatkin D. Mechanisms of TTNtv-Related Dilated Cardiomyopathy: Insights from Zebrafish Models. J Cardiovasc Dev Dis 2021; 8:jcdd8020010. [PMID: 33504111 PMCID: PMC7912658 DOI: 10.3390/jcdd8020010] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 01/19/2021] [Accepted: 01/22/2021] [Indexed: 12/15/2022] Open
Abstract
Dilated cardiomyopathy (DCM) is a common heart muscle disorder characterized by ventricular dilation and contractile dysfunction that is associated with significant morbidity and mortality. New insights into disease mechanisms and strategies for treatment and prevention are urgently needed. Truncating variants in the TTN gene, which encodes the giant sarcomeric protein titin (TTNtv), are the most common genetic cause of DCM, but exactly how TTNtv promote cardiomyocyte dysfunction is not known. Although rodent models have been widely used to investigate titin biology, they have had limited utility for TTNtv-related DCM. In recent years, zebrafish (Danio rerio) have emerged as a powerful alternative model system for studying titin function in the healthy and diseased heart. Optically transparent embryonic zebrafish models have demonstrated key roles of titin in sarcomere assembly and cardiac development. The increasing availability of sophisticated imaging tools for assessment of heart function in adult zebrafish has revolutionized the field and opened new opportunities for modelling human genetic disorders. Genetically modified zebrafish that carry a human A-band TTNtv have now been generated and shown to spontaneously develop DCM with age. This zebrafish model will be a valuable resource for elucidating the phenotype modifying effects of genetic and environmental factors, and for exploring new drug therapies.
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Affiliation(s)
- Celine F. Santiago
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia; (C.F.S.); (I.G.H.)
- St. Vincent’s Clinical School, Faculty of Medicine, UNSW Sydney, Kensington, NSW 2052, Australia
| | - Inken G. Huttner
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia; (C.F.S.); (I.G.H.)
- St. Vincent’s Clinical School, Faculty of Medicine, UNSW Sydney, Kensington, NSW 2052, Australia
| | - Diane Fatkin
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia; (C.F.S.); (I.G.H.)
- St. Vincent’s Clinical School, Faculty of Medicine, UNSW Sydney, Kensington, NSW 2052, Australia
- Cardiology Department, St. Vincent’s Hospital, Darlinghurst, NSW 2010, Australia
- Correspondence:
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13
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Discovery of TITIN Gene Truncating Variant Mutations and 5-Year Outcomes in Patients With Nonischemic Dilated Cardiomyopathy. Am J Cardiol 2020; 137:97-102. [PMID: 32998006 DOI: 10.1016/j.amjcard.2020.09.026] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 09/11/2020] [Accepted: 09/15/2020] [Indexed: 01/07/2023]
Abstract
Genetic factors play an important role in nonischemic dilated cardiomyopathy (NIDC). However, prime opportunities remain for genetic discovery and prognostic understanding. TITIN gene truncating variant mutations (TTNtv) are of interest because of their frequent appearance in NIDC series. We sought to discover known and novel TTNtv mutations in a NIDC cohort and assess 5-year outcomes. Patients with NIDC entered into the INSPIRE Registry with ≥3 years of follow-up were studied. Whole exome sequencing (WES) was performed using an Illumina Novaseq platform. Genetic analysis used Sentieon software and the GRCh38 human reference genome. Variant calls were annotated with ClinVar. Five-year outcomes were determined by functional assessment and ejection fraction (EF) as recovered (EF ≥50%), persistent (EF 21% to 49%), or progressive (left ventricular assist device, transplant, heart failure [HF] or arrhythmic death, or EF ≤20%). The study comprised 229 NIDC patients (age = 50 ± 15 years, 58% men). TTNtv's were discovered in 27 patients with 22 unique mutations; (7 known, 15 novel). TTNtv+ patients more frequently presented with severe NIDC (EF ≤20%) (p = 0.032). By 5-year, outcomes were worse in TTNtv+ patients (p = 0.027), and patients less often recovered (11% vs. 30%). Prognosis was similar with known and novel mutations. Nongenetic (e.g., environmental) cocausal risk factors for HF were frequently present, and these factors frequently appeared to act in concert with genetic variants to precipitate clinical HF. In conclusion, our study expands the library of likely pathogenic TTN mutations and increases our understanding of their clinical impact in association with other HF risk factors.
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14
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Abstract
PURPOSE OF REVIEW The purpose of this review is to provide an update on the recent advances in the genetics and genomics of dilated cardiomyopathy and heart failure. RECENT FINDINGS Over the last decade, the approach to the discovery of the genetic contribution to heart failure has evolved from investigation of rare variants implicated in Mendelian cardiomyopathies through linkage studies and candidate gene studies to the exploration of the contribution of common variants through large-scale genome-wide association and genome-first studies. The combination and integration of multiple of case-control heart failure cohorts, refinement of the heart failure phenotype, and utilization of large biobanks linked to electronic health records have advanced the understanding of the heritability of heart failure.
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Affiliation(s)
- Nosheen Reza
- Center for Inherited Cardiovascular Disease, Division of Cardiovascular Medicine, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, 11 South Tower, Room 11-145 3400 Civic Center Boulevard, Philadelphia, PA, 19104, USA.
| | - Anjali Tiku Owens
- Center for Inherited Cardiovascular Disease, Division of Cardiovascular Medicine, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, 11 South Tower, Room 11-145 3400 Civic Center Boulevard, Philadelphia, PA, 19104, USA
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15
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Jansen M, Baas AF, van Spaendonck-Zwarts KY, Ummels AS, van den Wijngaard A, Jongbloed JDH, van Slegtenhorst MA, Lekanne Deprez RH, Wessels MW, Michels M, Houweling AC, Hoorntje ET, Helderman-van den Enden PJTM, Barge-Schaapveld DQCM, Peter van Tintelen J, van den Berg MP, Wilde AAM, Ploos van Amstel HK, Hennekam EAM, Asselbergs FW, Sijbrands EJG, Dooijes D. Mortality Risk Associated With Truncating Founder Mutations in Titin. CIRCULATION-GENOMIC AND PRECISION MEDICINE 2020; 12:e002436. [PMID: 31112426 DOI: 10.1161/circgen.118.002436] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Background Truncating titin variants (TTNtv) are the most prevalent genetic cause of dilated cardiomyopathy, found in ≤25% of familial cases. Moreover, TTNtv associated with dilated cardiomyopathy are estimated to be present in 0.5% of the general population. The prognosis of asymptomatic carriers of TTNtv is poorly understood because TTNtv are associated with a highly variable phenotype. We aim to assess the natural history and clinical relevance of TTNtv by analyzing standardized mortality ratios (SMR) in multigenerational pedigrees and in close relatives of present-day patients. Methods Haplotype and genealogical analyses were performed on 3 recurrent TTNtv. Subsequently, the family tree mortality ratio method was used to compare all-cause mortality of subjects at an a priori 50% risk of carrying TTNtv to the general Dutch population. SMRs were stratified for sex, age, and calendar period. Subgroups were compared with Poisson regression. Similarly, SMRs were calculated in parents of 128 present-day dilated cardiomyopathy probands with TTNtv using the reverse parent-offspring method. Results The TTNtv were established as founder mutations and traced to 18th century ancestors. In 20 522 person-years, overall mortality was not significantly increased (SMR, 1.06; 95% CI, 0.95-1.18; P=0.162). However, mortality was significantly increased in subjects living after 1965 (SMR, 1.27; 95% CI, 1.04-1.53; P=0.009) and aged ≥60 years (SMR, 1.17; 95% CI, 1.01-1.35; P=0.02). The reverse parent-offspring analysis showed overall excess mortality (SMR, 1.26; 95% CI, 1.07-1.48; P=0.003), driven by subjects aged ≥60 years. Conclusions The natural history of the analyzed TTNtv shows a relatively mild disease course with significant excess mortality in elderly patients. With increasing life expectancy, TTNtv-associated morbidity and mortality will likely become more prevalent.
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Affiliation(s)
- Mark Jansen
- Department of Genetics (M.J., A.F.B., A.S.U., H.K.P.v.A., E.A.M.H., D.D.), University Medical Center Utrecht, Utrecht University, the Netherlands
| | - Annette F Baas
- Department of Genetics (M.J., A.F.B., A.S.U., H.K.P.v.A., E.A.M.H., D.D.), University Medical Center Utrecht, Utrecht University, the Netherlands
| | - Karin Y van Spaendonck-Zwarts
- Department of Clinical Genetics (K.Y.v.S.-Z., R.H.L.D., A.C.H.), Amsterdam University Medical Center, the Netherlands
| | - Amber S Ummels
- Department of Genetics (M.J., A.F.B., A.S.U., H.K.P.v.A., E.A.M.H., D.D.), University Medical Center Utrecht, Utrecht University, the Netherlands
| | - Arthur van den Wijngaard
- Department of Clinical Genetics, Maastricht University Medical Center, the Netherlands (A.v.d.W., P.J.T.M.H.-v.d.E.)
| | - Jan D H Jongbloed
- Department of Genetics (J.D.H.J., E.T.H., J.P.v.T.), University Medical Centre Groningen, University of Groningen, the Netherlands
| | - Marjon A van Slegtenhorst
- Department of Clinical Genetics (M.A.v.S., M.W.W.), Erasmus Medical Centre, Rotterdam, the Netherlands
| | - Ronald H Lekanne Deprez
- Department of Clinical Genetics (K.Y.v.S.-Z., R.H.L.D., A.C.H.), Amsterdam University Medical Center, the Netherlands
| | - Marja W Wessels
- Department of Clinical Genetics (M.A.v.S., M.W.W.), Erasmus Medical Centre, Rotterdam, the Netherlands
| | - Michelle Michels
- Department of Cardiology (M.M.), Erasmus Medical Centre, Rotterdam, the Netherlands
| | - Arjan C Houweling
- Department of Clinical Genetics (K.Y.v.S.-Z., R.H.L.D., A.C.H.), Amsterdam University Medical Center, the Netherlands
| | - Edgar T Hoorntje
- Department of Genetics (J.D.H.J., E.T.H., J.P.v.T.), University Medical Centre Groningen, University of Groningen, the Netherlands
| | | | | | - J Peter van Tintelen
- Department of Genetics (J.D.H.J., E.T.H., J.P.v.T.), University Medical Centre Groningen, University of Groningen, the Netherlands.,Durrer Center for Cardiovascular Research, Netherlands Heart Institute, Utrecht, the Netherlands (J.P.v.T., F.W.A.)
| | - Maarten P van den Berg
- Department of Cardiology (M.P.v.d.B.), University Medical Centre Groningen, University of Groningen, the Netherlands
| | - Arthur A M Wilde
- Department of Cardiology (A.A.M.W.), Amsterdam University Medical Center, the Netherlands
| | - Hans K Ploos van Amstel
- Department of Genetics (M.J., A.F.B., A.S.U., H.K.P.v.A., E.A.M.H., D.D.), University Medical Center Utrecht, Utrecht University, the Netherlands
| | - Eric A M Hennekam
- Department of Genetics (M.J., A.F.B., A.S.U., H.K.P.v.A., E.A.M.H., D.D.), University Medical Center Utrecht, Utrecht University, the Netherlands
| | - Folkert W Asselbergs
- Division of Heart and Lungs, Department of Cardiology (F.W.A.), University Medical Center Utrecht, Utrecht University, the Netherlands.,Durrer Center for Cardiovascular Research, Netherlands Heart Institute, Utrecht, the Netherlands (J.P.v.T., F.W.A.).,Institute of Cardiovascular Science (F.W.A.) and Health Data Research UK, Institute of Health Informatics (F.W.A.), University College London, United Kingdom
| | - Eric J G Sijbrands
- Department of Internal Medicine (E.J.G.S.), Erasmus Medical Centre, Rotterdam, the Netherlands
| | - Dennis Dooijes
- Department of Genetics (M.J., A.F.B., A.S.U., H.K.P.v.A., E.A.M.H., D.D.), University Medical Center Utrecht, Utrecht University, the Netherlands
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16
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Morales A, Kinnamon DD, Jordan E, Platt J, Vatta M, Dorschner MO, Starkey CA, Mead JO, Ai T, Burke W, Gastier-Foster J, Jarvik GP, Rehm HL, Nickerson DA, Hershberger RE. Variant Interpretation for Dilated Cardiomyopathy: Refinement of the American College of Medical Genetics and Genomics/ClinGen Guidelines for the DCM Precision Medicine Study. CIRCULATION-GENOMIC AND PRECISION MEDICINE 2020; 13:e002480. [PMID: 32160020 DOI: 10.1161/circgen.119.002480] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
BACKGROUND The hypothesis of the Dilated Cardiomyopathy Precision Medicine Study is that most dilated cardiomyopathy has a genetic basis. The study returns results to probands and, when indicated, to relatives. While both the American College of Medical Genetics and Genomics/Association for Molecular Pathology and ClinGen's MYH7-cardiomyopathy specifications provide relevant guidance for variant interpretation, further gene- and disease-specific considerations were required for dilated cardiomyopathy. To this end, we tailored the ClinGen MYH7-cardiomyopathy variant interpretation framework; the specifications implemented for the study are presented here. METHODS Modifications were created and approved by an external Variant Adjudication Oversight Committee. After a pilot using 81 probands, further adjustments were made, resulting in 27 criteria (9 modifications of the ClinGen MYH7 framework and reintroduction of 2 American College of Medical Genetics and Genomics/Association of Molecular Pathology criteria that were deemed not applicable by the ClinGen MYH7 working group). RESULTS These criteria were applied to 2059 variants in a test set of 97 probands. Variants were classified as benign (n=1702), likely benign (n=33), uncertain significance (n=71), likely pathogenic (likely pathogenic; n=12), and pathogenic (P; n=3). Only 2/15 likely pathogenic/P variants were identified in Non-Hispanic African ancestry probands. CONCLUSIONS We tailored the ClinGen MYH7 criteria for our study. Our preliminary data show that 15/97 (15.5%) probands have likely pathogenic/P variants, most of which were identified in probands of Non-Hispanic European ancestry. We anticipate continued evolution of our approach, one that will be informed by new insights on variant interpretation and a greater understanding of the genetic architecture of dilated cardiomyopathy. CLINICAL TRIAL REGISTRATION URL: https://www.clinicaltrials.gov; Unique identifier: NCT03037632.
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Affiliation(s)
- Ana Morales
- Division of Human Genetics, Department of Internal Medicine (A.M., D.D.K., E.J., C.S., J.M., T.A., R.E.H.), The Ohio State University, Columbus
| | - Daniel D Kinnamon
- Division of Human Genetics, Department of Internal Medicine (A.M., D.D.K., E.J., C.S., J.M., T.A., R.E.H.), The Ohio State University, Columbus
| | - Elizabeth Jordan
- Division of Human Genetics, Department of Internal Medicine (A.M., D.D.K., E.J., C.S., J.M., T.A., R.E.H.), The Ohio State University, Columbus
| | - Julia Platt
- Stanford Center for Inherited Cardiovascular Disease, Stanford University, Palo Alto, CA (J.P.)
| | - Matteo Vatta
- Department of Medical and Molecular Genetics, Indiana University, Indianapolis (M.V.).,Invitae, San Francisco, CA (M.V.)
| | | | - Carl A Starkey
- Division of Human Genetics, Department of Internal Medicine (A.M., D.D.K., E.J., C.S., J.M., T.A., R.E.H.), The Ohio State University, Columbus
| | - Jonathan O Mead
- Division of Human Genetics, Department of Internal Medicine (A.M., D.D.K., E.J., C.S., J.M., T.A., R.E.H.), The Ohio State University, Columbus
| | - Tomohiko Ai
- Division of Human Genetics, Department of Internal Medicine (A.M., D.D.K., E.J., C.S., J.M., T.A., R.E.H.), The Ohio State University, Columbus
| | - Wylie Burke
- Department of Bioethics and Humanities (W.B.), University of Washington, SA
| | - Julie Gastier-Foster
- Institute for Genomic Medicine, Nationwide Children's Hospital, Columbus, OH (J.G.-F.)
| | - Gail P Jarvik
- Division of Medical Genetics, Department of Medicine (G.P.J.), University of Washington, SA.,Department of Genome Sciences (G.P.J.), University of Washington, SA
| | - Heidi L Rehm
- Center for Genomic Medicine, Massachusetts General Hospital, Boston (H.L.R.).,Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA (H.L.R.)
| | | | - Ray E Hershberger
- Division of Human Genetics, Department of Internal Medicine (A.M., D.D.K., E.J., C.S., J.M., T.A., R.E.H.), The Ohio State University, Columbus.,Division of Cardiovascular Medicine, Department of Internal Medicine (R.E.H.), The Ohio State University, Columbus
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17
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Zhou J, Ng B, Ko NSJ, Fiedler LR, Khin E, Lim A, Sahib NE, Wu Y, Chothani SP, Schafer S, Bay BH, Sinha RA, Cook SA, Yen PM. Titin truncations lead to impaired cardiomyocyte autophagy and mitochondrial function in vivo. Hum Mol Genet 2020; 28:1971-1981. [PMID: 30715350 DOI: 10.1093/hmg/ddz033] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2018] [Revised: 01/21/2019] [Accepted: 01/31/2019] [Indexed: 01/21/2023] Open
Abstract
Titin-truncating variants (TTNtv) are the most common genetic cause of dilated cardiomyopathy. TTNtv occur in ~1% of the general population and causes subclinical cardiac remodeling in asymptomatic carriers. In rat models with either proximal or distal TTNtv, we previously showed altered cardiac metabolism at baseline and impaired cardiac function in response to stress. However, the molecular mechanism(s) underlying these effects remains unknown. In the current study, we used rat models of TTNtv to investigate the effect of TTNtv on autophagy and mitochondrial function, which are essential for maintaining cellular metabolic homeostasis and cardiac function. In both the proximal and distal TTNtv rat models, we found increased levels of LC3B-II and p62 proteins, indicative of diminished autophagic degradation. The accumulation of autophagosomes and p62 protein in cardiomyocytes was also demonstrated by electron microscopy and immunochemistry, respectively. Impaired autophagy in the TTNtv heart was associated with increased phosphorylation of mTOR and decreased protein levels of the lysosomal protease, cathepsin B. In addition, TTNtv hearts showed mitochondrial dysfunction, as evidenced by decreased oxygen consumption rate in cardiomyocytes, increased levels of reactive oxygen species and mitochondrial protein ubiquitination. We also observed increased acetylation of mitochondrial proteins associated with decreased NAD+/NADH ratio in the TTNtv hearts. mTORC1 inhibitor, rapamycin, was able to rescue the impaired autophagy in TTNtv hearts. In summary, TTNtv leads to impaired autophagy and mitochondrial function in the heart. These changes not only provide molecular mechanisms that underlie TTNtv-associated ventricular remodeling but also offer potential targets for its intervention.
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Affiliation(s)
- Jin Zhou
- Cardiovascular and Metabolic Disorders Program, Duke-National University of Singapore, Singapore, Singapore
| | - Benjamin Ng
- Cardiovascular and Metabolic Disorders Program, Duke-National University of Singapore, Singapore, Singapore.,National Heart Centre Singapore, Singapore, Singapore
| | - Nicole S J Ko
- Cardiovascular and Metabolic Disorders Program, Duke-National University of Singapore, Singapore, Singapore
| | - Lorna R Fiedler
- Cardiovascular and Metabolic Disorders Program, Duke-National University of Singapore, Singapore, Singapore
| | - Ester Khin
- Cardiovascular and Metabolic Disorders Program, Duke-National University of Singapore, Singapore, Singapore
| | - Andrea Lim
- Cardiovascular and Metabolic Disorders Program, Duke-National University of Singapore, Singapore, Singapore
| | - Norliza E Sahib
- Cardiovascular and Metabolic Disorders Program, Duke-National University of Singapore, Singapore, Singapore
| | - Yajun Wu
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Sonia P Chothani
- Cardiovascular and Metabolic Disorders Program, Duke-National University of Singapore, Singapore, Singapore
| | - Sebastian Schafer
- Cardiovascular and Metabolic Disorders Program, Duke-National University of Singapore, Singapore, Singapore.,National Heart Centre Singapore, Singapore, Singapore
| | - Boon-Huat Bay
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Rohit A Sinha
- Cardiovascular and Metabolic Disorders Program, Duke-National University of Singapore, Singapore, Singapore.,Department of Endocrinology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India
| | - Stuart A Cook
- Cardiovascular and Metabolic Disorders Program, Duke-National University of Singapore, Singapore, Singapore.,National Heart Centre Singapore, Singapore, Singapore.,National Heart and Lung Institute, Imperial College London, London, UK
| | - Paul M Yen
- Cardiovascular and Metabolic Disorders Program, Duke-National University of Singapore, Singapore, Singapore.,Duke Molecular Physiology Institute, Departments of Medicine and Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC, USA
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18
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Zaunbrecher RJ, Abel AN, Beussman K, Leonard A, von Frieling-Salewsky M, Fields PA, Pabon L, Reinecke H, Yang X, Macadangdang J, Kim DH, Linke WA, Sniadecki NJ, Regnier M, Murry CE. Cronos Titin Is Expressed in Human Cardiomyocytes and Necessary for Normal Sarcomere Function. Circulation 2019; 140:1647-1660. [PMID: 31587567 PMCID: PMC6911360 DOI: 10.1161/circulationaha.119.039521] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
BACKGROUND The giant sarcomere protein titin is important in both heart health and disease. Mutations in the gene encoding for titin (TTN) are the leading known cause of familial dilated cardiomyopathy. The uneven distribution of these mutations within TTN motivated us to seek a more complete understanding of this gene and the isoforms it encodes in cardiomyocyte (CM) sarcomere formation and function. METHODS To investigate the function of titin in human CMs, we used CRISPR/Cas9 to generate homozygous truncations in the Z disk (TTN-Z-/-) and A-band (TTN-A-/-) regions of the TTN gene in human induced pluripotent stem cells. The resulting CMs were characterized with immunostaining, engineered heart tissue mechanical measurements, and single-cell force and calcium measurements. RESULTS After differentiation, we were surprised to find that despite the more upstream mutation, TTN-Z-/--CMs had sarcomeres and visibly contracted, whereas TTN-A-/--CMs did not. We hypothesized that sarcomere formation was caused by the expression of a recently discovered isoform of titin, Cronos, which initiates downstream of the truncation in TTN-Z-/--CMs. Using a custom Cronos antibody, we demonstrate that this isoform is expressed and integrated into myofibrils in human CMs. TTN-Z-/--CMs exclusively express Cronos titin, but these cells produce lower contractile force and have perturbed myofibril bundling compared with controls expressing both full-length and Cronos titin. Cronos titin is highly expressed in human fetal cardiac tissue, and when knocked out in human induced pluripotent stem cell derived CMs, these cells exhibit reduced contractile force and myofibrillar disarray despite the presence of full-length titin. CONCLUSIONS We demonstrate that Cronos titin is expressed in developing human CMs and is able to support partial sarcomere formation in the absence of full-length titin. Furthermore, Cronos titin is necessary for proper sarcomere function in human induced pluripotent stem cell derived CMs. Additional investigation is necessary to understand the molecular mechanisms of this novel isoform and how it contributes to human cardiac disease.
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Affiliation(s)
- Rebecca J. Zaunbrecher
- Department of Bioengineering, University of Washington, Seattle, WA
- Center for Cardiovascular Biology, University of Washington, Seattle, WA
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA
| | - Ashley N. Abel
- Center for Cardiovascular Biology, University of Washington, Seattle, WA
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA
| | - Kevin Beussman
- Department of Mechanical Engineering, University of Washington, Seattle, WA
- Center for Cardiovascular Biology, University of Washington, Seattle, WA
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA
| | - Andrea Leonard
- Department of Mechanical Engineering, University of Washington, Seattle, WA
- Center for Cardiovascular Biology, University of Washington, Seattle, WA
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA
| | | | - Paul A. Fields
- Department of Pathology, University of Washington, Seattle, WA
- Center for Cardiovascular Biology, University of Washington, Seattle, WA
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA
| | - Lil Pabon
- Department of Pathology, University of Washington, Seattle, WA
- Center for Cardiovascular Biology, University of Washington, Seattle, WA
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA
| | - Hans Reinecke
- Department of Pathology, University of Washington, Seattle, WA
- Center for Cardiovascular Biology, University of Washington, Seattle, WA
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA
| | - Xiulan Yang
- Department of Pathology, University of Washington, Seattle, WA
- Center for Cardiovascular Biology, University of Washington, Seattle, WA
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA
| | - Jesse Macadangdang
- Department of Bioengineering, University of Washington, Seattle, WA
- Center for Cardiovascular Biology, University of Washington, Seattle, WA
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA
| | - Deok-Ho Kim
- Department of Bioengineering, University of Washington, Seattle, WA
- Center for Cardiovascular Biology, University of Washington, Seattle, WA
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA
| | - Wolfgang A. Linke
- Institute of Physiology II, University of Muenster, Robert-Koch-Str. 27b, D-48149 Muenster, Germany
- Deutsches Zentrum für Herz-Kreislaufforschung, Partner Site Goettingen, Germany
| | - Nathan J. Sniadecki
- Department of Mechanical Engineering, University of Washington, Seattle, WA
- Center for Cardiovascular Biology, University of Washington, Seattle, WA
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA
| | - Michael Regnier
- Department of Bioengineering, University of Washington, Seattle, WA
- Center for Cardiovascular Biology, University of Washington, Seattle, WA
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA
| | - Charles E. Murry
- Department of Bioengineering, University of Washington, Seattle, WA
- Department of Pathology, University of Washington, Seattle, WA
- Center for Cardiovascular Biology, University of Washington, Seattle, WA
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA
- Department of Medicine/Cardiology, University of Washington, Seattle, WA
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19
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Yeh JK, Liu WH, Wang CY, Lu JJ, Chen CH, Wu-Chou YH, Chang PY, Chang SC, Yang CH, Tsai ML, Ho MY, Hsieh IC, Wen MS. Targeted Next Generation Sequencing for Genetic Mutations of Dilated Cardiomyopathy. ACTA CARDIOLOGICA SINICA 2019; 35:571-584. [PMID: 31879508 PMCID: PMC6859096 DOI: 10.6515/acs.201911_35(6).20190402a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Accepted: 04/02/2019] [Indexed: 01/19/2023]
Abstract
BACKGROUND Approximately one-third of cases of dilated cardiomyopathy (DCM) are caused by genetic mutations. With new sequencing technologies, numerous variants have been associated with this inherited cardiomyopathy, however the prevalence and genotype-phenotype correlations in different ethnic cohorts remain unclear. This study aimed to investigate the variants in Chinese DCM patients and correlate them with clinical presentations and prognosis. METHODS AND RESULTS From September 2013 to December 2016, 70 index patients underwent DNA sequencing for 12 common disease-causing genes with next generation sequencing. Using a bioinformatics filtering process, 12 rare truncating variants (7 nonsense variants, 4 frameshift variants, and 1 splice site variant) and 29 rare missense variants were identified. Of these, 3 patients were double heterozygotes and 10 patients were compound heterozygotes. Overall, 47.1% (33/70) of the index patients had the seputatively pathogenic variants. The majority (33/41, 80.4%) of these variants were located in titin (TTN). More than 80% of the TTN variants (27/33, 81.8%) were distributed in the A band region of the sarcomere. Patients carrying these variants did not have a different phenotype in disease severity, clinical outcome and reversibility of ventricular function compared with non-carriers. CONCLUSIONS Several new rare variants were identified in a Chinese population in this study, indicating that there are ethnic differences in genetic mutations in DCM patients. TTN remains the major disease-causing gene. Our results could be a reference for future genetic tests in Chinese populations. No specific genotype-phenotype correlations were found, however a prospective large cohort study may be needed to confirm our findings.
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Affiliation(s)
| | - Wei-Hsiu Liu
- Department of Laboratory Medicine, Linkou Chang Gung Memorial Hospital
| | - Chao-Yung Wang
- Department of Cardiology
- College of Medicine, Chang Gung University, Taoyuan
| | - Jang-Jih Lu
- Department of Laboratory Medicine, Linkou Chang Gung Memorial Hospital
- College of Medicine, Chang Gung University, Taoyuan
| | | | - Yah-Huei Wu-Chou
- Department of Medical Research, Linkou Chang Gung Memorial Hospital and Graduate of Institute of Clinical Medical Science, Chang Gung University, Taoyuan, Taiwan
| | - Pi-Yueh Chang
- Department of Laboratory Medicine, Linkou Chang Gung Memorial Hospital
| | - Shih-Cheng Chang
- Department of Laboratory Medicine, Linkou Chang Gung Memorial Hospital
| | | | | | | | - I-Chang Hsieh
- Department of Cardiology
- College of Medicine, Chang Gung University, Taoyuan
| | - Ming-Shien Wen
- Department of Cardiology
- College of Medicine, Chang Gung University, Taoyuan
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20
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Haggerty CM, Damrauer S, Levin MG, Birtwell D, Carey DJ, Golden AM, Hartzel DN, Hu Y, Judy R, Kelly MA, Kember RL, Kirchner HL, Leader JB, Liang L, McDermott-Roe C, Babu A, Morley M, Nealy Z, Person TN, Pulenthiran A, Small A, Smelser DT, Stahl RC, Sturm AC, Williams H, Baras A, Margulies KB, Cappola TP, Dewey FE, Verma A, Zhang X, Correa A, Hall ME, Wilson JG, Ritchie MD, Rader DJ, Murray MF, Fornwalt BK, Arany Z. Genomics-First Evaluation of Heart Disease Associated With Titin-Truncating Variants. Circulation 2019; 140:42-54. [PMID: 31216868 PMCID: PMC6602806 DOI: 10.1161/circulationaha.119.039573] [Citation(s) in RCA: 82] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2019] [Accepted: 04/19/2019] [Indexed: 01/01/2023]
Abstract
BACKGROUND Truncating variants in the Titin gene (TTNtvs) are common in individuals with idiopathic dilated cardiomyopathy (DCM). However, a comprehensive genomics-first evaluation of the impact of TTNtvs in different clinical contexts, and the evaluation of modifiers such as genetic ancestry, has not been performed. METHODS We reviewed whole exome sequence data for >71 000 individuals (61 040 from the Geisinger MyCode Community Health Initiative (2007 to present) and 10 273 from the PennMedicine BioBank (2013 to present) to identify anyone with TTNtvs. We further selected individuals with TTNtvs in exons highly expressed in the heart (proportion spliced in [PSI] >0.9). Using linked electronic health records, we evaluated associations of TTNtvs with diagnoses and quantitative echocardiographic measures, including subanalyses for individuals with and without DCM diagnoses. We also reviewed data from the Jackson Heart Study to validate specific analyses for individuals of African ancestry. RESULTS Identified with a TTNtv in a highly expressed exon (hiPSI) were 1.2% individuals in PennMedicine BioBank and 0.6% at Geisinger. The presence of a hiPSI TTNtv was associated with increased odds of DCM in individuals of European ancestry (odds ratio [95% CI]: 18.7 [9.1-39.4] {PennMedicine BioBank} and 10.8 [7.0-16.0] {Geisinger}). hiPSI TTNtvs were not associated with DCM in individuals of African ancestry, despite a high DCM prevalence (odds ratio, 1.8 [0.2-13.7]; P=0.57). Among 244 individuals of European ancestry with DCM in PennMedicine BioBank, hiPSI TTNtv carriers had lower left ventricular ejection fraction (β=-12%, P=3×10-7), and increased left ventricular diameter (β=0.65 cm, P=9×10-3). In the Geisinger cohort, hiPSI TTNtv carriers without a cardiomyopathy diagnosis had more atrial fibrillation (odds ratio, 2.4 [1.6-3.6]) and heart failure (odds ratio, 3.8 [2.4-6.0]), and lower left ventricular ejection fraction (β=-3.4%, P=1×10-7). CONCLUSIONS Individuals of European ancestry with hiPSI TTNtv have an abnormal cardiac phenotype characterized by lower left ventricular ejection fraction, irrespective of the clinical manifestation of cardiomyopathy. Associations with arrhythmias, including atrial fibrillation, were observed even when controlling for cardiomyopathy diagnosis. In contrast, no association between hiPSI TTNtvs and DCM was discerned among individuals of African ancestry. Given these findings, clinical identification of hiPSI TTNtv carriers may alter clinical management strategies.
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Affiliation(s)
| | - Scott Damrauer
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Michael G. Levin
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - David Birtwell
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | | | | | | | | | - Renae Judy
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | | | - Rachel L. Kember
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | | | | | - Lusha Liang
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | | | - Apoorva Babu
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Michael Morley
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | | | | | | | - Aeron Small
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | | | | | | | - Heather Williams
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Aris Baras
- Regeneron Genetics Center, Tarrytown, NY
| | | | - Thomas P. Cappola
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | | | - Anurag Verma
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Xinyuang Zhang
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Adolfo Correa
- Department of Medicine, University of Mississippi Medical Center, Jackson, MS
| | - Michael E. Hall
- Department of Medicine, University of Mississippi Medical Center, Jackson, MS
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS
| | - James G. Wilson
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS
| | - Marylyn D. Ritchie
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Daniel J. Rader
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | | | | | - Zoltan Arany
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
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21
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van Tintelen JP, Pinto YM. Additional Genetic Variants in Inherited Dilated Cardiomyopathy: Just Another Brick in the Wall? CIRCULATION-GENOMIC AND PRECISION MEDICINE 2019; 11:e002249. [PMID: 30012838 DOI: 10.1161/circgen.118.002249] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- J Peter van Tintelen
- Departments of Clinical Genetics (J.P.v.T.) .,Amsterdam Cardiovascular Science, Academic Medical Center, University of Amsterdam, the Netherlands. Department of Genetics, University Medical Center Utrecht, the Netherlands (J.P.v.T.)
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22
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Dai G, Pu Z, Cheng X, Yin J, Chen J, Xu T, Zhang H, Li Z, Chen X, Chen J, Qin Y, Yang S. Whole-Exome Sequencing Reveals Novel Genetic Variation for Dilated Cardiomyopathy in Pediatric Chinese Patients. Pediatr Cardiol 2019; 40:950-957. [PMID: 30993396 DOI: 10.1007/s00246-019-02096-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Accepted: 03/22/2019] [Indexed: 12/30/2022]
Abstract
Dilated cardiomyopathy (DCM) is characterized by left or bilateral ventricular dilation and systolic dysfunction without rational conditions, which can lead to progressive heart failure and sudden cardiac death. Most of the pathogenic genes have been reported in adult population by locus mapping in familial cases and animal model studies. However, it still remains challenging to decipher the role of genetics in the etiology of pediatric DCM. We applied whole-exome sequencing (WES) for 30 sporadic pediatric DCM subjects and 100 non-DCM local controls. We identified the pathogenic mutations using bioinformatics tools based on genomic strategies synergistically and confirmed mutations by Sanger sequencing. We identified compound heterozygous nonsense mutations in DSP (c.3799C > T, p.R1267X; c.4444G > T, p.E1482X). In sporadic cases, the two heterozygous mutations in XIRP2 were identified. Then we performed an exome-wide association study with 30 case and 100 control subjects. Interestingly, we could not identify TTN truncating variants in all cases. Collectively, we observed a significant risk signal between carriers of TTN deleterious missense variants and DCM risk (odds ratio 4.0, 95% confidence interval 1.1-22.2, p = 3.12 × 10-2). Our observations expanded the spectrum of mutations and were valuable in the pre- and postnatal screening and genetic diagnosis for DCM.
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Affiliation(s)
- Genyin Dai
- Department of Cardiology, Children's Hospital of Nanjing Medical University, 72 Guangzhou Road, Nanjing, 210008, China
| | - Zhening Pu
- Center of Clinical Research, Wuxi People's Hospital of Nanjing Medical University, Wuxi, 214023, China
| | - Xueying Cheng
- Department of Cardiology, Children's Hospital of Nanjing Medical University, 72 Guangzhou Road, Nanjing, 210008, China
| | - Jie Yin
- Department of Cardiology, Children's Hospital of Nanjing Medical University, 72 Guangzhou Road, Nanjing, 210008, China
| | - Jun Chen
- Department of Echocardiography, Children's Hospital of Nanjing Medical University, Nanjing, 210008, China
| | - Ting Xu
- Department of Cardiology, Children's Hospital of Nanjing Medical University, 72 Guangzhou Road, Nanjing, 210008, China
| | - Han Zhang
- Department of Cardiology, Children's Hospital of Nanjing Medical University, 72 Guangzhou Road, Nanjing, 210008, China
| | - Zewei Li
- Department of Cardiology, Children's Hospital of Nanjing Medical University, 72 Guangzhou Road, Nanjing, 210008, China
| | - Xuan Chen
- Department of Cardiology, Children's Hospital of Nanjing Medical University, 72 Guangzhou Road, Nanjing, 210008, China
| | - Jinlong Chen
- Department of Cardiology, Children's Hospital of Nanjing Medical University, 72 Guangzhou Road, Nanjing, 210008, China
| | - Yuming Qin
- Department of Cardiology, Children's Hospital of Nanjing Medical University, 72 Guangzhou Road, Nanjing, 210008, China.
| | - Shiwei Yang
- Department of Cardiology, Children's Hospital of Nanjing Medical University, 72 Guangzhou Road, Nanjing, 210008, China.
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23
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Yotti R, Seidman CE, Seidman JG. Advances in the Genetic Basis and Pathogenesis of Sarcomere Cardiomyopathies. Annu Rev Genomics Hum Genet 2019; 20:129-153. [PMID: 30978303 DOI: 10.1146/annurev-genom-083118-015306] [Citation(s) in RCA: 94] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM) are common heart muscle disorders that are caused by pathogenic variants in sarcomere protein genes. HCM is characterized by unexplained cardiac hypertrophy (increased chamber wall thickness) that is accompanied by enhanced cardiac contractility and impaired relaxation. DCM is defined as increased ventricular chamber volume with contractile impairment. In this review, we discuss recent analyses that provide new insights into the molecular mechanisms that cause these conditions. HCM studies have uncovered the critical importance of conformational changes that occur during relaxation and enable energy conservation, which are frequently disturbed by HCM mutations. DCM studies have demonstrated the considerable prevalence of truncating variants in titin and have discerned that these variants reduce contractile function by impairing sarcomerogenesis. These new pathophysiologic mechanisms open exciting opportunities to identify new pharmacological targets and develop future cardioprotective strategies.
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Affiliation(s)
- Raquel Yotti
- Department of Cardiology, Hospital General Universitario Gregorio Marañón, Instituto de Investigación Sanitaria Gregorio Marañón, 28007 Madrid, Spain; .,Centro de Investigación Biomédica en Red en Enfermedades Cardiovasculares (CIBERCV), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Christine E Seidman
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA; , .,Cardiovascular Division and Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA.,Howard Hughes Medical Institute, Chevy Chase, Maryland 20815, USA
| | - Jonathan G Seidman
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA; ,
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24
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Kellermayer D, Smith JE, Granzier H. Titin mutations and muscle disease. Pflugers Arch 2019; 471:673-682. [PMID: 30919088 DOI: 10.1007/s00424-019-02272-5] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 03/11/2019] [Indexed: 12/12/2022]
Abstract
The introduction of next-generation sequencing technology has revealed that mutations in the gene that encodes titin (TTN) are linked to multiple skeletal and cardiac myopathies. The most prominent of these myopathies is dilated cardiomyopathy (DCM). Over 60 genes are linked to the etiology of DCM, but by far, the leading cause of DCM is mutations in TTN with truncating variants in TTN (TTNtvs) associated with familial DCM in ∼ 20% of the cases. Titin is a large (3-4 MDa) and abundant protein that forms the third myofilament type of striated muscle where it spans half the sarcomere, from the Z-disk to the M-line. The underlying mechanisms by which titin mutations induce disease are poorly understood and targeted therapies are not available. Here, we review what is known about TTN mutations in muscle disease, with a major focus on DCM. We highlight that exon skipping might provide a possible therapeutic avenue to address diseases that arise from TTNtvs.
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Affiliation(s)
- Dalma Kellermayer
- Department of Cellular and Molecular Medicine, University of Arizona, MRB 325. 1656 E Mabel Street, Tucson, AZ, 85724-5217, USA.,Sarver Molecular Cardiovascular Research Program, University of Arizona, Tucson, AZ, 85721, USA
| | - John E Smith
- Department of Cellular and Molecular Medicine, University of Arizona, MRB 325. 1656 E Mabel Street, Tucson, AZ, 85724-5217, USA.,Sarver Molecular Cardiovascular Research Program, University of Arizona, Tucson, AZ, 85721, USA
| | - Henk Granzier
- Department of Cellular and Molecular Medicine, University of Arizona, MRB 325. 1656 E Mabel Street, Tucson, AZ, 85724-5217, USA. .,Sarver Molecular Cardiovascular Research Program, University of Arizona, Tucson, AZ, 85721, USA.
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25
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Akinrinade O, Heliö T, Lekanne Deprez RH, Jongbloed JDH, Boven LG, van den Berg MP, Pinto YM, Alastalo TP, Myllykangas S, Spaendonck-Zwarts KV, van Tintelen JP, van der Zwaag PA, Koskenvuo J. Relevance of Titin Missense and Non-Frameshifting Insertions/Deletions Variants in Dilated Cardiomyopathy. Sci Rep 2019; 9:4093. [PMID: 30858397 PMCID: PMC6412046 DOI: 10.1038/s41598-019-39911-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 02/04/2019] [Indexed: 12/30/2022] Open
Abstract
Recent advancements in next generation sequencing (NGS) technology have led to the identification of the giant sarcomere gene, titin (TTN), as a major human disease gene. Truncating variants of TTN (TTNtv) especially in the A-band region account for 20% of dilated cardiomyopathy (DCM) cases. Much attention has been focused on assessment and interpretation of TTNtv in human disease; however, missense and non-frameshifting insertions/deletions (NFS-INDELs) are difficult to assess and interpret in clinical diagnostic workflow. Targeted sequencing covering all exons of TTN was performed on a cohort of 530 primary DCM patients from three cardiogenetic centres across Europe. Using stringent bioinformatic filtering, twenty-nine and two rare TTN missense and NFS-INDELs variants predicted deleterious were identified in 6.98% and 0.38% of DCM patients, respectively. However, when compared with those identified in the largest available reference population database, no significant enrichment of such variants was identified in DCM patients. Moreover, DCM patients and reference individuals had comparable frequencies of splice-region missense variants with predicted splicing alteration. DCM patients and reference populations had comparable frequencies of rare predicted deleterious TTN missense variants including splice-region missense variants suggesting that these variants are not independently causative for DCM. Hence, these variants should be classified as likely benign in the clinical diagnostic workflow, although a modifier effect cannot be excluded at this stage.
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Affiliation(s)
- Oyediran Akinrinade
- Children's Hospital, Institute of Clinical Medicine, Helsinki University Central Hospital, University of Helsinki, Helsinki, Finland.
- Institute of Biomedicine, University of Helsinki, Helsinki, Finland.
| | - Tiina Heliö
- Heart and Lung Centre, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Ronald H Lekanne Deprez
- Department of Clinical Genetics, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
| | - Jan D H Jongbloed
- University of Groningen, University Medical Centre Groningen, Department of Genetics, Groningen, The Netherlands
| | - Ludolf G Boven
- University of Groningen, University Medical Centre Groningen, Department of Genetics, Groningen, The Netherlands
| | - Maarten P van den Berg
- Department of Cardiology, University of Groningen, University Medical Centre Groningen, Groningen, The Netherlands
| | - Yigal M Pinto
- Department of Cardiology, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
| | - Tero-Pekka Alastalo
- Children's Hospital, Institute of Clinical Medicine, Helsinki University Central Hospital, University of Helsinki, Helsinki, Finland
- Blueprint Genetics, Helsinki, Finland
| | - Samuel Myllykangas
- Institute of Biomedicine, University of Helsinki, Helsinki, Finland
- Blueprint Genetics, Helsinki, Finland
| | - Karin van Spaendonck-Zwarts
- Department of Clinical Genetics, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
| | - J Peter van Tintelen
- Department of Clinical Genetics, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
- Durrer Centre for Cardiovascular Research, Netherlands Heart Institute, Utrecht, The Netherlands
| | - Paul A van der Zwaag
- University of Groningen, University Medical Centre Groningen, Department of Genetics, Groningen, The Netherlands
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26
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Interpretation of Genomic Sequencing Results in Healthy and Ill Newborns: Results from the BabySeq Project. Am J Hum Genet 2019; 104:76-93. [PMID: 30609409 DOI: 10.1016/j.ajhg.2018.11.016] [Citation(s) in RCA: 148] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 11/23/2018] [Indexed: 12/27/2022] Open
Abstract
Genomic sequencing provides many opportunities in newborn clinical care, but the challenges of interpreting and reporting newborn genomic sequencing (nGS) results need to be addressed for its broader and effective application. The BabySeq Project is a pilot randomized clinical trial that explores the medical, behavioral, and economic impacts of nGS in well newborns and those admitted to a neonatal intensive care unit (NICU). Here we present childhood-onset and actionable adult-onset disease risk, carrier status, and pharmacogenomics findings from nGS of 159 newborns in the BabySeq Project. nGS revealed a risk of childhood-onset disease in 15/159 (9.4%) newborns; none of the disease risks were anticipated based on the infants' known clinical or family histories. nGS also revealed actionable adult-onset disease risk in 3/85 (3.5%) newborns whose parents consented to receive this information. Carrier status for recessive diseases and pharmacogenomics variants were reported in 88% and 5% of newborns, respectively. Additional indication-based analyses were performed in 29/32 (91%) NICU newborns and 6/127 (5%) healthy newborns who later had presentations that prompted a diagnostic analysis. No variants that sufficiently explained the reason for the indications were identified; however, suspicious but uncertain results were reported in five newborns. Testing parental samples contributed to the interpretation and reporting of results in 13/159 (8%) newborns. Our results suggest that nGS can effectively detect risk and carrier status for a wide range of disorders that are not detectable by current newborn screening assays or predicted based on the infant's known clinical or family history, and the interpretation of results can substantially benefit from parental testing.
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27
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28
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Repeat genetic testing with targeted capture sequencing in primary arrhythmia syndrome and cardiomyopathy. Eur J Hum Genet 2017; 25:1313-1323. [PMID: 29255176 DOI: 10.1038/s41431-017-0004-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 08/01/2017] [Accepted: 08/04/2017] [Indexed: 11/09/2022] Open
Abstract
In inherited primary arrhythmia syndromes (PAS) and cardiomyopathies (CMP), the yield of genetic testing varies between 20 and 75% in different diseases according to studies performed in the pre next-generation sequencing (NGS) era. It is unknown whether retesting historical negative samples with NGS techniques is worthwhile. Therefore, we assessed the value of NGS-based panel testing in previously genotype negative-phenotype positive probands. We selected 107 patients (47 PAS and 60 CMP) with a clear phenotype who remained genotype negative after genetic analysis of the main genes implicated in their specific phenotype. Targeted sequencing of the coding regions of 71 PAS- and CMP-related genes was performed. Variant interpretation and classification was done according to a cardiology-specific scoring algorithm ('Amsterdam criteria') and the ACMG-AMP criteria. Co-segregation analysis was performed when DNA and clinical data of family members were available. Finally, a genetic diagnosis could be established in 21 patients (20%), 5 PAS (11%) and 16 CMP (27%) patients, respectively. The increased detection rate was due to sequencing of novel genes in 52% of the cases and due to technical failures with the historical analysis in 48%. A total of 118 individuals were informed about their carrier state and either reassured or scheduled for proper follow-up. To conclude, genetic retesting in clinically overt PAS and CMP cases, who were genotype negative with older techniques, resulted in an additional genetic diagnosis in up to 20% of the cases. This clearly supports a policy for genetic retesting with NGS-based panels.
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29
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Gerull B. Between Disease-Causing and an Innocent Bystander: The Role of Titin as a Modifier in Hypertrophic Cardiomyopathy. Can J Cardiol 2017; 33:1217-1220. [DOI: 10.1016/j.cjca.2017.07.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 07/17/2017] [Accepted: 07/17/2017] [Indexed: 01/22/2023] Open
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30
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Sabater-Molina M, Pérez-Sánchez I, Hernández del Rincón J, Gimeno J. Genetics of hypertrophic cardiomyopathy: A review of current state. Clin Genet 2017; 93:3-14. [DOI: 10.1111/cge.13027] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 03/13/2017] [Accepted: 03/21/2017] [Indexed: 12/18/2022]
Affiliation(s)
- M. Sabater-Molina
- Inherited Cardiac Disease Unit; University Hospital Virgen Arrixaca; Murcia Spain
- Internal Medicine Department, University of Murcia; Murcia Spain
| | - I. Pérez-Sánchez
- Inherited Cardiac Disease Unit; University Hospital Virgen Arrixaca; Murcia Spain
| | - J.P. Hernández del Rincón
- Internal Medicine Department, University of Murcia; Murcia Spain
- Pathology Department; Institute of Legal Medicine; Murcia Spain
| | - J.R. Gimeno
- Inherited Cardiac Disease Unit; University Hospital Virgen Arrixaca; Murcia Spain
- Internal Medicine Department, University of Murcia; Murcia Spain
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31
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Forleo C, D’Erchia AM, Sorrentino S, Manzari C, Chiara M, Iacoviello M, Guaricci AI, De Santis D, Musci RL, La Spada A, Marangelli V, Pesole G, Favale S. Targeted next-generation sequencing detects novel gene-phenotype associations and expands the mutational spectrum in cardiomyopathies. PLoS One 2017; 12:e0181842. [PMID: 28750076 PMCID: PMC5531468 DOI: 10.1371/journal.pone.0181842] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 07/08/2017] [Indexed: 12/19/2022] Open
Abstract
Cardiomyopathies are a heterogeneous group of primary diseases of the myocardium, including hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM), and arrhythmogenic right ventricular cardiomyopathy (ARVC), with higher morbidity and mortality. These diseases are genetically diverse and associated with rare mutations in a large number of genes, many of which overlap among the phenotypes. To better investigate the genetic overlap between these three phenotypes and to identify new genotype–phenotype correlations, we designed a custom gene panel consisting of 115 genes known to be associated with cardiomyopathic phenotypes and channelopathies. A cohort of 38 unrelated patients, 16 affected by DCM, 14 by HCM and 8 by ARVC, was recruited for the study on the basis of more severe phenotypes and family history of cardiomyopathy and/or sudden death. We detected a total of 142 rare variants in 40 genes, and all patients were found to be carriers of at least one rare variant. Twenty-eight of the 142 rare variants were also predicted as potentially pathogenic variants and found in 26 patients. In 23 out of 38 patients, we found at least one novel potential gene–phenotype association. In particular, we detected three variants in OBSCN gene in ARVC patients, four variants in ANK2 gene and two variants in DLG1, TRPM4, and AKAP9 genes in DCM patients, two variants in PSEN2 gene and four variants in AKAP9 gene in HCM patients. Overall, our results confirmed that cardiomyopathic patients could carry multiple rare gene variants; in addition, our investigation of the genetic overlap among cardiomyopathies revealed new gene–phenotype associations. Furthermore, as our study confirms, data obtained using targeted next-generation sequencing could provide a remarkable contribution to the molecular diagnosis of cardiomyopathies, early identification of patients at risk for arrhythmia development, and better clinical management of cardiomyopathic patients.
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Affiliation(s)
- Cinzia Forleo
- Cardiology Unit, Department of Emergency and Organ Transplantation, University of Bari Aldo Moro, Bari, Italy
- * E-mail: (CF); (AMD)
| | - Anna Maria D’Erchia
- Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari Aldo Moro, Bari, Italy
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), National Research Council, Bari, Italy
- * E-mail: (CF); (AMD)
| | - Sandro Sorrentino
- Cardiology Unit, Department of Emergency and Organ Transplantation, University of Bari Aldo Moro, Bari, Italy
| | - Caterina Manzari
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), National Research Council, Bari, Italy
| | - Matteo Chiara
- Department of Biosciences, University of Milano, Milano, Italy
| | - Massimo Iacoviello
- Cardiology Unit, Department of Emergency and Organ Transplantation, University of Bari Aldo Moro, Bari, Italy
| | - Andrea Igoren Guaricci
- Cardiology Unit, Department of Emergency and Organ Transplantation, University of Bari Aldo Moro, Bari, Italy
| | - Delia De Santis
- Cardiology Unit, Department of Emergency and Organ Transplantation, University of Bari Aldo Moro, Bari, Italy
| | - Rita Leonarda Musci
- Cardiology Unit, Department of Emergency and Organ Transplantation, University of Bari Aldo Moro, Bari, Italy
| | - Antonino La Spada
- Cardiology Unit, Department of Emergency and Organ Transplantation, University of Bari Aldo Moro, Bari, Italy
| | - Vito Marangelli
- Cardiology Unit, Department of Emergency and Organ Transplantation, University of Bari Aldo Moro, Bari, Italy
| | - Graziano Pesole
- Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari Aldo Moro, Bari, Italy
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), National Research Council, Bari, Italy
| | - Stefano Favale
- Cardiology Unit, Department of Emergency and Organ Transplantation, University of Bari Aldo Moro, Bari, Italy
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Zhang C, Zhang H, Wu G, Luo X, Zhang C, Zou Y, Wang H, Hui R, Wang J, Song L. Titin-Truncating Variants Increase the Risk of Cardiovascular Death in Patients With Hypertrophic Cardiomyopathy. Can J Cardiol 2017; 33:1292-1297. [PMID: 28822653 DOI: 10.1016/j.cjca.2017.05.020] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2017] [Revised: 05/16/2017] [Accepted: 05/29/2017] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Titin-truncating variants (TTNtv) have been detected in a variety of cardiomyopathies and represent the most common cause of dilated cardiomyopathy. However, their significance in hypertrophic cardiomyopathy (HCM) is still unclear. METHODS The titin gene (TTN) was sequenced for truncating variants in a cohort of 529 Chinese patients with HCM and 307 healthy controls. Baseline and follow-up clinical data (for 4.7 ± 3.2 years) from these patients were obtained. RESULTS We identified 13 and 8 TTNtv in patients with HCM (13 of 529 [2.5%]) and controls (8 of 307 [2.6%]), respectively. The prevalence of TTNtv in patients with HCM and in healthy controls was comparable (P = 0.895). There were no significant differences in baseline characteristics between patients with and those without TTNtv. However, during follow-up, patients with TTNtv (3 of 13 [23.1%]) were more likely to experience cardiovascular death compared with those without TTNtv (39 of 516 [7.6%]) [adjusted hazard ratio, 6.88; 95% confidence interval, 2.04-23.20; P = 0.002). CONCLUSIONS Our study suggests that TTNtv might be a genetic modifier of HCM and confer an increased risk for cardiovascular death.
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Affiliation(s)
- Ce Zhang
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China; Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Disease, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Hongju Zhang
- Department of Cardiovascular Disease, Mayo Clinic, Rochester, Minnesota, USA; Department of Medical Ultrasonics, the Seventh Affiliated Hospital of Sun Yat-Sen University, Shenzhen, China
| | - Guixin Wu
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China; Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Disease, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xiaoliang Luo
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Disease, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Channa Zhang
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yubao Zou
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Disease, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Hu Wang
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Rutai Hui
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Jizheng Wang
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
| | - Lei Song
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Disease, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
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Janin A, N'Guyen K, Habib G, Dauphin C, Chanavat V, Bouvagnet P, Eschalier R, Streichenberger N, Chevalier P, Millat G. Truncating mutations on myofibrillar myopathies causing genes as prevalent molecular explanations on patients with dilated cardiomyopathy. Clin Genet 2017; 92:616-623. [PMID: 28436997 DOI: 10.1111/cge.13043] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 04/11/2017] [Accepted: 04/21/2017] [Indexed: 12/16/2022]
Abstract
Dilated cardiomyopathy (DCM) is one of the leading causes of heart failure with high morbidity and mortality. More than 40 genes have been reported to cause DCM. To provide new insights into the pathophysiology of dilated cardiomyopathy, a next-generation sequencing (NGS) workflow based on a panel of 48 cardiomyopathies-causing genes was used to analyze a cohort of 222 DCM patients. Truncating variants were detected on 63 unrelated DCM cases (28.4%). Most of them were identified, as expected, on TTN (29 DCM probands), but truncating variants were also identified on myofibrillar myopathies causing genes in 17 DCM patients (7.7% of the DCM cohort): 10 variations on FLNC and 7 variations on BAG3 . This study confirms that truncating variants on myofibrillar myopathies causing genes are frequently associated with dilated cardiomyopathies and also suggest that FLNC mutations could be considered as a common cause of dilated cardiomyopathy. Molecular approaches that would allow to detect systematically truncating variants in FLNC and BAG3 into genetic testing should significantly increase test sensitivity, thereby allowing earlier diagnosis and therapeutic intervention for many patients with dilated cardiomyopathy.
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Affiliation(s)
- A Janin
- Laboratoire de Cardiogénétique Moléculaire, Centre de Biologie et Pathologie Est, Hospices Civils de Lyon, Lyon, France.,NeuroMyoGen Institute, CNRS UMR 5310 - INSERM U1217, Université de Lyon 1, Lyon, France
| | - K N'Guyen
- Department of Medical Genetics, Timone Hospital, Marseille Teaching Hospital, Marseille, France
| | - G Habib
- Cardiology Department, Timone Hospital, Marseille, France
| | - C Dauphin
- Image Science for Interventional Techniques (ISIT), UMR6284, and CHU Clermont-Ferrand, Cardiology Department, Clermont Université, Université d'Auvergne, Cardio Vascular Interventional Therapy and Imaging (CaVITI), Clermont-Ferrand, France
| | - V Chanavat
- Laboratoire de Cardiogénétique Moléculaire, Centre de Biologie et Pathologie Est, Hospices Civils de Lyon, Lyon, France.,NeuroMyoGen Institute, CNRS UMR 5310 - INSERM U1217, Université de Lyon 1, Lyon, France
| | - P Bouvagnet
- NeuroMyoGen Institute, CNRS UMR 5310 - INSERM U1217, Université de Lyon 1, Lyon, France.,Groupe Hospitalier Est, Hospices Civils de Lyon, Service de Cardiologie C, Lyon, France
| | - R Eschalier
- Image Science for Interventional Techniques (ISIT), UMR6284, and CHU Clermont-Ferrand, Cardiology Department, Clermont Université, Université d'Auvergne, Cardio Vascular Interventional Therapy and Imaging (CaVITI), Clermont-Ferrand, France
| | - N Streichenberger
- NeuroMyoGen Institute, CNRS UMR 5310 - INSERM U1217, Université de Lyon 1, Lyon, France.,Laboratoire d'Anatomo-Cyto-Pathologie, Centre de Biologie et Pathologie Est, Hospices Civils de Lyon, Lyon, France
| | - P Chevalier
- Hôpital Cardiologique Louis-Pradel, Service de Rythmologie, Bron, France
| | - G Millat
- Laboratoire de Cardiogénétique Moléculaire, Centre de Biologie et Pathologie Est, Hospices Civils de Lyon, Lyon, France.,NeuroMyoGen Institute, CNRS UMR 5310 - INSERM U1217, Université de Lyon 1, Lyon, France
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34
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Genetic epidemiology of titin-truncating variants in the etiology of dilated cardiomyopathy. Biophys Rev 2017; 9:207-223. [PMID: 28510119 PMCID: PMC5498329 DOI: 10.1007/s12551-017-0265-7] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 04/10/2017] [Indexed: 02/07/2023] Open
Abstract
Heart failure (HF) is a complex clinical syndrome defined by the inability of the heart to pump enough blood to meet the body's metabolic demands. Major causes of HF are cardiomyopathies (diseases of the myocardium associated with mechanical and/or electrical dysfunction), among which the most common form is dilated cardiomyopathy (DCM). DCM is defined by ventricular chamber enlargement and systolic dysfunction with normal left ventricular wall thickness, which leads to progressive HF. Over 60 genes are linked to the etiology of DCM. Titin (TTN) is the largest known protein in biology, spanning half the cardiac sarcomere and, as such, is a basic structural and functional unit of striated muscles. It is essential for heart development as well as mechanical and regulatory functions of the sarcomere. Next-generation sequencing (NGS) in clinical DCM cohorts implicated truncating variants in titin (TTNtv) as major disease alleles, accounting for more than 25% of familial DCM cases, but these variants have also been identified in 2-3% of the general population, where these TTNtv blur diagnostic and clinical utility. Taking into account the published TTNtv and their association to DCM, it becomes clear that TTNtv harm the heart with position-dependent occurrence, being more harmful when present in the A-band TTN, presumably with dominant negative/gain-of-function mechanisms. However, these insights are challenged by the depiction of position-independent toxicity of TTNtv acting via haploinsufficient alleles, which are sufficient to induce cardiac pathology upon stress. In the current review, we provide an overview of TTN and discuss studies investigating various TTN mutations. We also present an overview of different mechanisms postulated or experimentally validated in the pathogenicity of TTNtv. DCM-causing genes are also discussed with respect to non-truncating mutations in the etiology of DCM. One way of understanding pathogenic variants is probably to understand the context in which they may or may not affect protein-protein interactions, changes in cell signaling, and substrate specificity. In this regard, we also provide a brief overview of TTN interactions in situ. Quantitative models in the risk assessment of TTNtv are also discussed. In summary, we highlight the importance of gene-environment interactions in the etiology of DCM and further mechanistic studies used to delineate the pathways which could be targeted in the management of DCM.
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35
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Titin-truncating variants affect heart function in disease cohorts and the general population. Nat Genet 2016; 49:46-53. [PMID: 27869827 PMCID: PMC5201198 DOI: 10.1038/ng.3719] [Citation(s) in RCA: 224] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 10/18/2016] [Indexed: 11/08/2022]
Abstract
Titin-truncating variants (TTNtv) commonly cause dilated cardiomyopathy (DCM). TTNtv are also encountered in ∼1% of the general population, where they may be silent, perhaps reflecting allelic factors. To better understand TTNtv, we integrated TTN allelic series, cardiac imaging and genomic data in humans and studied rat models with disparate TTNtv. In patients with DCM, TTNtv throughout titin were significantly associated with DCM. Ribosomal profiling in rat showed the translational footprint of premature stop codons in Ttn, TTNtv-position-independent nonsense-mediated degradation of the mutant allele and a signature of perturbed cardiac metabolism. Heart physiology in rats with TTNtv was unremarkable at baseline but became impaired during cardiac stress. In healthy humans, machine-learning-based analysis of high-resolution cardiac imaging showed TTNtv to be associated with eccentric cardiac remodeling. These data show that TTNtv have molecular and physiological effects on the heart across species, with a continuum of expressivity in health and disease.
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Jansweijer JA, Nieuwhof K, Russo F, Hoorntje ET, Jongbloed JDH, Lekanne Deprez RH, Postma AV, Bronk M, van Rijsingen IAW, de Haij S, Biagini E, van Haelst PL, van Wijngaarden J, van den Berg MP, Wilde AAM, Mannens MMAM, de Boer RA, van Spaendonck-Zwarts KY, van Tintelen JP, Pinto YM. Truncating titin mutations are associated with a mild and treatable form of dilated cardiomyopathy. Eur J Heart Fail 2016; 19:512-521. [PMID: 27813223 DOI: 10.1002/ejhf.673] [Citation(s) in RCA: 117] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2016] [Revised: 09/02/2016] [Accepted: 09/05/2016] [Indexed: 11/09/2022] Open
Abstract
AIMS Truncating titin mutations (tTTN) occur in 25% of dilated cardiomyopathy (DCM) cases, but the phenotype and severity of disease they cause have not yet been systematically studied. We studied whether tTTN variants are associated with a clinically distinguishable form of DCM. METHODS AND RESULTS We compared clinical data on DCM probands and relatives with a tTTN mutation (n = 45, n = 73), LMNA mutation (n = 28, n = 29), and probands who tested negative for both genes [idiopathic DCM (iDCM); n = 60]. Median follow-up was at least 2.5 years in each group. TTN subjects presented with DCM at higher age than LMNA subjects (probands 47.9 vs. 40.4 years, P = 0.004; relatives 59.8 vs. 47.0 years, P = 0.01), less often developed LVEF <35% [probands hazard ratio (HR) 0.38, P = 0.002], had higher age of death (probands 70.4 vs. 59.4 years, P < 0.001; relatives 74.1 vs. 58.4 years, P = 0.008), and had better composite outcome (malignant ventricular arrhythmia, heart transplantation, or death; probands HR 0.09, P < 0.001; relatives HR 0.21, P = 0.02) than LMNA subjects and iDCM subjects (HR 0.36, P = 0.07). An LVEF increase of at least 10% occurred in 46.9% of TTN subjects after initiation of standard heart failure treatment, while this only occurred in 6.5% of LMNA subjects (P < 0.001) and 18.5% of iDCM subjects (P = 0.02). This was confirmed in families with co-segregation, in which the 10% point LVEF increase occurred in 55.6% of subjects (P = 0.003 vs. LMNA, P = 0.079 vs. iDCM). CONCLUSIONS This study shows that tTTN-associated DCM is less severe at presentation and more amenable to standard therapy than LMNA mutation-induced DCM or iDCM.
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Affiliation(s)
- Joeri A Jansweijer
- AMC Heart Center, Department of Clinical and Experimental Cardiology, Academic Medical Center Amsterdam, University of Amsterdam, Amsterdam, The Netherlands
| | - Karin Nieuwhof
- Department of Clinical Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Francesco Russo
- Department of Clinical Genetics, Academic Medical Center Amsterdam, University of Amsterdam, Amsterdam, The Netherlands
| | - Edgar T Hoorntje
- Department of Clinical Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Jan D H Jongbloed
- Department of Clinical Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Ronald H Lekanne Deprez
- Department of Clinical Genetics, Academic Medical Center Amsterdam, University of Amsterdam, Amsterdam, The Netherlands
| | - Alex V Postma
- Department of Anatomy, Embryology and Physiology, Academic Medical Center Amsterdam, University of Amsterdam, Amsterdam, The Netherlands
| | - Marieke Bronk
- Department of Clinical Genetics, Academic Medical Center Amsterdam, University of Amsterdam, Amsterdam, The Netherlands
| | - Ingrid A W van Rijsingen
- AMC Heart Center, Department of Clinical and Experimental Cardiology, Academic Medical Center Amsterdam, University of Amsterdam, Amsterdam, The Netherlands
| | - Simone de Haij
- Department of Clinical Genetics, Academic Medical Center Amsterdam, University of Amsterdam, Amsterdam, The Netherlands
| | - Elena Biagini
- Department of Cardiology, S. Orsola-Malpighi Hospital, Bologna University, Italy
| | | | | | - Maarten P van den Berg
- Department of Cardiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Arthur A M Wilde
- AMC Heart Center, Department of Clinical and Experimental Cardiology, Academic Medical Center Amsterdam, University of Amsterdam, Amsterdam, The Netherlands
| | - Marcel M A M Mannens
- Department of Clinical Genetics, Academic Medical Center Amsterdam, University of Amsterdam, Amsterdam, The Netherlands
| | - Rudolf A de Boer
- Department of Cardiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Karin Y van Spaendonck-Zwarts
- Department of Clinical Genetics, Academic Medical Center Amsterdam, University of Amsterdam, Amsterdam, The Netherlands
| | - J Peter van Tintelen
- Department of Clinical Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.,Department of Clinical Genetics, Academic Medical Center Amsterdam, University of Amsterdam, Amsterdam, The Netherlands
| | - Yigal M Pinto
- AMC Heart Center, Department of Clinical and Experimental Cardiology, Academic Medical Center Amsterdam, University of Amsterdam, Amsterdam, The Netherlands
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Deo RC. Alternative Splicing, Internal Promoter, Nonsense-Mediated Decay, or All Three: Explaining the Distribution of Truncation Variants in Titin. ACTA ACUST UNITED AC 2016; 9:419-425. [PMID: 27625338 PMCID: PMC5068190 DOI: 10.1161/circgenetics.116.001513] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Accepted: 08/12/2016] [Indexed: 12/01/2022]
Abstract
Supplemental Digital Content is available in the text. Background— Truncating mutations in the giant sarcomeric gene Titin are the most common type of genetic alteration in dilated cardiomyopathy. Detailed studies have amassed a wealth of information about truncating variant position in cases and controls. Nonetheless, considerable confusion exists as to how to interpret the pathogenicity of these variants, hindering our ability to make useful recommendations to patients. Methods and Results— Building on our recent discovery of a conserved internal promoter within the Titin gene, we sought to develop an integrative statistical model to explain the observed pattern of Titin truncation variants in patients with dilated cardiomyopathy and population controls. We amassed Titin truncation mutation information from 1714 human dilated cardiomyopathy cases and >69 000 controls and found 3 factors explaining the distribution of Titin mutations: (1) alternative splicing, (2) whether the internal promoter Cronos isoform was disrupted, and (3) whether the distal C terminus was targeted (in keeping with the observation that truncation variants in this region escape nonsense-mediated decay and continue to be incorporated in the sarcomere). A model using these 3 factors had strong predictive performance with an area under the receiver operating characteristic curve of 0.81. Accordingly, individuals with either the most severe form of dilated cardiomyopathy or whose mutations demonstrated clear family segregation experienced the highest risk profile across all 3 components. Conclusions— We conclude that quantitative models derived from large-scale human genetic and phenotypic data can be applied to help overcome the ever-growing challenges of genetic data interpretation. Results of our approach can be found at http://cvri.ucsf.edu/~deo/TTNtruncationvariant.html.
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Affiliation(s)
- Rahul C Deo
- From the Department of Medicine, Institute for Human Genetics, California Institute for Quantitative Biosciences and Cardiovascular Research Institute, University of California, San Francisco.
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38
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Kayvanpour E, Sedaghat-Hamedani F, Amr A, Lai A, Haas J, Holzer DB, Frese KS, Keller A, Jensen K, Katus HA, Meder B. Genotype-phenotype associations in dilated cardiomyopathy: meta-analysis on more than 8000 individuals. Clin Res Cardiol 2016; 106:127-139. [DOI: 10.1007/s00392-016-1033-6] [Citation(s) in RCA: 99] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 08/23/2016] [Indexed: 02/06/2023]
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