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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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Mahdavi M, Mohsen-Pour N, Maleki M, Hesami M, Naderi N, Houshmand G, Rasouli Jazi HR, Shahzadi H, Kalayinia S. Whole-exome sequencing identified compound heterozygous variants in the TTN gene causing Salih myopathy with dilated cardiomyopathy in an Iranian family. Cardiol Young 2021; 32:1-6. [PMID: 34782032 DOI: 10.1017/s1047951121004455] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
BACKGROUND Salih myopathy, characterised by both congenital myopathy and fatal dilated cardiomyopathy, is an inherited muscle disorder that affects skeletal and cardiac muscles. TTN has been identified as the main cause of this myopathy, the enormous size of this gene poses a formidable challenge to molecular genetic diagnostics. METHOD In the present study, whole-exome sequencing, cardiac MRI, and metabolic parameter assessment were performed to investigate the genetic causes of Salih myopathy in a consanguineous Iranian family who presented with titinopathy involving both skeletal and heart muscles in an autosomal recessive inheritance pattern. RESULTS Two missense variants of TTN gene (NM_001267550.2), namely c.61280A>C (p. Gln20427Pro) and c.54970G>A (p. Gly18324Ser), were detected and segregations were confirmed by polymerase chain reaction-based Sanger sequencing. CONCLUSIONS The compound heterozygous variants, c.61280A>C, (p. Gln20427Pro) and c.54970G>A, (p. Gly18324Ser) in the TTN gene appear to be the cause of Salih myopathy and dilated cardiomyopathy in the family presented. Whole-exome sequencing is an effective molecular diagnostic tool to identify the causative genetic variants of large genes such as TTN.
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Affiliation(s)
- Mohammad Mahdavi
- Cardiogenetic Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Neda Mohsen-Pour
- Zanjan Pharmaceutical Biotechnology Research Center, Zanjan University of Medical Sciences, Zanjan, Iran
| | - Majid Maleki
- 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
| | - Niloofar Naderi
- Cardiogenetic Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Golnaz Houshmand
- Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Hamid R Rasouli Jazi
- Biotechnology Research Center, Malek Ashtar University of Technology, Tehran, Iran
| | - Hossein Shahzadi
- 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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Peng Y, Miao J, Zhai Y, Fang G, Wang C, Wang Y, Zhao X, Dong J. Identification of Novel TTN Mutations in Three Chinese Familial Dilated Cardiomyopathy Pedigrees by Whole Exome Sequencing. CARDIOVASCULAR INNOVATIONS AND APPLICATIONS 2020. [DOI: 10.15212/cvia.2019.0579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Familial dilated cardiomyopathy (DCM) is associated with numerous genes, especially those of the sarcomere family. The titin gene (TTN) consists of 365 exons and encodes the largest sarcomere protein (titin) in our bodies. Titin is associated with many diseases, such as hypertrophic
cardiomyopathy and DCM. Here we screened three Chinese families affected by DCM, and found that each harbors a stop-gain or splice site mutation in TTN (c.G20137T,c. G52522T,c.44610-2A>C). Assessment of the probands by electrocardiogram, B-mode echocardiography, and cardiac magnetic
resonance imaging revealed impaired cardiac function, arrhythmia, or abnormal cardiac structure. In conclusion, using whole exome sequencing, we found three unreported TTN mutations associated with DCM. This has expanded the TTN mutation spectrum of Chinese DCM patients, especially
in Henan, the most populous province. These data provide new genetic targets for the diagnosis and treatment of DCM, and will increase our understanding of the relationship between TTN mutation and DCM clinical symptoms.
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Affiliation(s)
- Ying Peng
- Department of Cardiology, The First Affiliated Hospital, Zhengzhou University, Zhengzhou, Henan 450052, P. R. China
| | - Jinxin Miao
- Academy of Chinese Medical Sciences, Henan University of Chinese Medicine, Zhengzhou, Henan 450046, P. R. China
| | - Yafei Zhai
- Department of Cardiology, The First Affiliated Hospital, Zhengzhou University, Zhengzhou, Henan 450052, P. R. China
| | - Guangming Fang
- Department of Cardiology, The First Affiliated Hospital, Zhengzhou University, Zhengzhou, Henan 450052, P. R. China
| | - Chuchu Wang
- College of Life Sciences, Zhengzhou University, Zhengzhou, Henan 450000, P.R. China
| | - Yaohe Wang
- Sino-British Research Center for Molecular Oncology, National Center for the International Research in Cell and Gene Therapy, School of Basic Sciences, Academy of Medical Sciences, Zhengzhou University, Zhengzhou, Henan 450052, P. R. China
| | - Xiaoyan Zhao
- Department of Cardiology, The First Affiliated Hospital, Zhengzhou University, Zhengzhou, Henan 450052, P. R. China
| | - Jianzeng Dong
- Department of Cardiology, The First Affiliated Hospital, Zhengzhou University, Zhengzhou, Henan 450052, P. R. China
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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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Whole-exome sequencing reveals doubly novel heterozygous Myosin Binding Protein C and Titin mutations in a Chinese patient with severe dilated cardiomyopathy. Cardiol Young 2018; 28:1410-1414. [PMID: 30109841 DOI: 10.1017/s1047951118001403] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND Dilated Cardiomyopathy is a serious heart disorder that may induce sudden cardiac death and heart failure. Significant progress has been made in understanding the molecular basis of dilated cardiomyopathy. In previous studies, mutations in more than fifty genes have been identified in dilated cardiomyopathy patients. The purpose of this study was to detect the genetic lesion in a family from the central south of China affected by severe dilated cardiomyopathy. METHODS Whole-exome sequencing combined with cardiomyopathy-related genes list were used to analyse the mutations of the proband. Co-segregation analysis was performed by Sanger sequencing.Results and conclusionsTwo novel heterozygous mutations - Myosin Binding Protein C: p.L1014RfsX6 and Titin: p.R9793X - were identified in the proband. The deletion mutation c.3041delT/p.L1014RfsX6 caused a premature stop codon at position 1020 in exon 28 of the Myosin Binding Protein C. The nonsense mutation, c.29377 C>T/ p. R9793X, of Titin was located in the highly evolutionarily conserved domain, resulting in truncation of the Titin protein as well. Co-segregation analysis further revealed that the Myosin Binding Protein C mutation came from his mother and the Titin mutation came from his father. Both mutations are reported in dilated cardiomyopathy patients for the first time. Our study not only provides a unique example of the genes and molecular mechanisms involved in dilated cardiomyopathy but also expands the spectrum of Myosin Binding Protein C and Titin mutations and contributes to the genetic diagnosis and counselling of dilated cardiomyopathy patients.
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Zhang SB, Liu YX, Fan LL, Huang H, Li JJ, Jin JY, Xiang R. A novel heterozygous variant p.(Trp538Arg) of SYNM is identified by whole-exome sequencing in a Chinese family with dilated cardiomyopathy. Ann Hum Genet 2018; 83:95-99. [PMID: 30276801 DOI: 10.1111/ahg.12287] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2018] [Revised: 08/13/2018] [Accepted: 08/13/2018] [Indexed: 12/19/2022]
Abstract
Dilated cardiomyopathy (DCM) is a relatively frequent myocardial disease that may lead to heart failure, syncope, and sudden cardiac death. Genetic factors play important roles in the etiology of the disease. To date, at least 50 genes have been identified in patients with DCM, among them, only three mutations have been reported in Synemin (SYNM) gene. In this study, we investigate a Chinese family of three generations with four patients with DCM. Employing whole-exome sequencing (WES) and bioinformatics strategies, a novel heterozygous missense mutation p.(Trp538Arg) of SYNM was identified and cosegregated with the affected family members. The missense mutation locates in the C-terminal domain of SYNM and leads to a substitution of tryptophan by arginine and may cause the structure change of synemin protein. In conclusion, we employed WES to detect the mutations of DCM patients and identified a novel likely pathogenic mutation in SYNM gene. Our study not only expands the spectrum of SYNM mutations, it further confirms that mutations in SYMN may underlie nonfamilial DCM, and offers genetic testing information to additional DCM patients.
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Affiliation(s)
- Shu-Bing Zhang
- Department of Cell Biology, School of Life Sciences, Central South University, Changsha, China
| | - Yu-Xing Liu
- Department of Cell Biology, School of Life Sciences, Central South University, Changsha, China
| | - Liang-Liang Fan
- Department of Cell Biology, School of Life Sciences, Central South University, Changsha, China
| | - Hao Huang
- Department of Cell Biology, School of Life Sciences, Central South University, Changsha, China
| | - Jing-Jing Li
- Department of Cell Biology, School of Life Sciences, Central South University, Changsha, China
| | - Jie-Yuan Jin
- Department of Cell Biology, School of Life Sciences, Central South University, Changsha, China
| | - Rong Xiang
- Department of Cell Biology, School of Life Sciences, Central South University, Changsha, China.,Department of Cardiology, the Second Xiangya Hospital of Central South University, Changsha, China
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RNA binding protein 24 deletion disrupts global alternative splicing and causes dilated cardiomyopathy. Protein Cell 2018; 10:405-416. [PMID: 30267374 PMCID: PMC6538757 DOI: 10.1007/s13238-018-0578-8] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 08/24/2018] [Indexed: 01/08/2023] Open
Abstract
RNA splicing contributes to a broad spectrum of post-transcriptional gene regulation during normal development, as well as pathological manifestation of heart diseases. However, the functional role and regulation of splicing in heart failure remain poorly understood. RNA binding protein (RBP), a major component of the splicing machinery, is a critical factor in this process. RNA binding motif protein 24 (RBM24) is a tissue-specific RBP which is highly expressed in human and mouse heart. Previous studies demonstrated the functional role of RBM24 in the embryonic heart development. However, the role of RBM24 in postnatal heart development and heart disease has not been investigated. In this paper, using conditional RBM24 knockout mice, we demonstrated that ablation of RBM24 in postnatal heart led to rapidly progressive dilated cardiomyopathy (DCM), heart failure, and postnatal lethality. Global splicing profiling revealed that RBM24 regulated a network of genes related to cardiac function and diseases. Knockout of RBM24 resulted in misregulation of these splicing transitions which contributed to the subsequent development of cardiomyopathy. Notably, our analysis identified RBM24 as a splice factor that determined the splicing switch of a subset of genes in the sacomeric Z-disc complex, including Titin, the major disease gene of DCM and heart failure. Together, this study identifies regulation of RNA splicing by RBM24 as a potent player in remodeling of heart during postnatal development, and provides novel mechanistic insights to the pathogenesis of DCM.
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Huang H, Chen YQ, Fan LL, Guo S, Li JJ, Jin JY, Xiang R. Whole-exome sequencing identifies a novel mutation of GPD1L (R189X) associated with familial conduction disease and sudden death. J Cell Mol Med 2017; 22:1350-1354. [PMID: 29077258 PMCID: PMC5783853 DOI: 10.1111/jcmm.13409] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 08/31/2017] [Indexed: 01/21/2023] Open
Abstract
Cardiac conduction disease (CCD) is a serious disorder and the leading cause of mortality worldwide. It is characterized by arrhythmia, syncope or even sudden cardiac death caused by the dysfunction of cardiac voltage‐gated channel. Previous study has demonstrated that mutations in genes encoding voltage‐gated channel and related proteins were the crucial genetic lesion of CCD. In this study, we employed whole‐exome sequencing to explore the potential causative genes in a Chinese family with ventricular tachycardia and syncope. A novel nonsense mutation (c.565C>T/p.R189X) of glycerol‐3‐phosphate dehydrogenase‐like (GPD1L) was identified and co‐segregated with the affected family members. GPD1L is a crucial interacting protein of SCN5A, a gene encoded sodium channel α‐subunit Nav1.5 and mainly associated with Brugada syndrome (BrS). The novel mutation (c.565C>T/p.R189X) may result in a premature stop codon at position 189 in exon 4 of the GPD1L gene and lead to functional haploinsufficiency of GPD1L due to mRNA carrying this mutation will be degraded by nonsense‐mediated mRNA decay, which has been confirmed by Western blot in HEK293 cells transfected HIS‐GPD1L plasmid. The levels of GPD1L decreasing may disturb the function of Nav1.5 and induce arrhythmia and syncope in the end. In conclusion, our study not only further supported the important role of GPD1L in CCD, but also expanded the spectrum of GPD1L mutations and will contribute to the genetic diagnosis and counselling of families with CCD.
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Affiliation(s)
- Hao Huang
- School of Life Sciences, Central South University, Changsha, China
| | - Ya-Qin Chen
- Department of Cardiology, the Second Xiangya Hospital of Central South University, Changsha, China
| | - Liang-Liang Fan
- School of Life Sciences, Central South University, Changsha, China
| | - Shuai Guo
- School of Life Sciences, Central South University, Changsha, China
| | - Jing-Jing Li
- School of Life Sciences, Central South University, Changsha, China
| | - Jie-Yuan Jin
- School of Life Sciences, Central South University, Changsha, China
| | - Rong Xiang
- School of Life Sciences, Central South University, Changsha, China.,Department of Cardiology, the Second Xiangya Hospital of Central South University, Changsha, China
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Wang S, Li L, Tao R, Gao Y. Ion channelopathies associated genetic variants as the culprit for sudden unexplained death. Forensic Sci Int 2017; 275:128-137. [PMID: 28363160 DOI: 10.1016/j.forsciint.2017.03.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 02/23/2017] [Accepted: 03/13/2017] [Indexed: 11/29/2022]
Abstract
Forensic identification of sudden unexplained death (SUD) has always been a ticklish issue because it used to be defined as sudden death without a conclusive diagnosis after autopsy. However, benefiting from the developments in genome research, a growing body of evidence points to the importance of ion channelopathies associated genetic variants in the pathogenesis of SUD. Genetic diagnosis of the deceased is also a new trend in epidemiological studies, for it enables the undertaking for preventive approach in individuals with high risks. In this review, we briefly discuss the molecular structure of ion channels and the role of genetic variants in regulating their functions as well as the diverse mechanisms underlying the ion channelopathies at gene level.
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Affiliation(s)
- Shouyu Wang
- Department of Forensic Medicine, Medical College of Soochow University, Suzhou 215123, Jiangsu, China
| | - Lijuan Li
- Department of Forensic Medicine, Medical College of Soochow University, Suzhou 215123, Jiangsu, China
| | - Ruiyang Tao
- Department of Forensic Medicine, Medical College of Soochow University, Suzhou 215123, Jiangsu, China
| | - Yuzhen Gao
- Department of Forensic Medicine, Medical College of Soochow University, Suzhou 215123, Jiangsu, China.
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