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Huse S, Acharya S, Agrawal S, J H, Sachdev A, Ghulaxe Y, Sarda P, Chavada J. Recent Advances in Inherited Cardiac Arrhythmias and Their Genetic Testing. Cureus 2023; 15:e47653. [PMID: 38021622 PMCID: PMC10668889 DOI: 10.7759/cureus.47653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 10/25/2023] [Indexed: 12/01/2023] Open
Abstract
Inherited arrhythmias, encompassing conditions such as cardiomyopathies, cardiac ion channel disorders, and coronary heart disease, represent the common causes that elevate the threat of sudden cardiac death among adults. Researchers have pinpointed the genes responsible for these hereditary arrhythmias in the last 30 years. Concurrently, it has become clear that the genetic makeup underlying these conditions is more intricate than previously understood. Evolution in DNA sequencing techniques, particularly next-generation sequencing, has empowered us to learn these intricate hereditary characteristics. Genetic testing is crucial in diagnosing, assessing risk, and determining treatment for individuals with these conditions and their family members. The need for collaborative endeavors to comprehend and address these uncommon yet potentially life-threatening disorders is becoming more evident. This review aims to inform readers of the latest advances in understanding hereditary arrhythmias and provide the groundwork for collaborative genetic testing initiatives to characterize these disorders in the general population.
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Affiliation(s)
- Shreyash Huse
- Department of Medicine, Jawaharlal Nehru Medical College, Datta Meghe Institute of Higher Education and Research, Wardha, IND
| | - Sourya Acharya
- Department of Medicine, Jawaharlal Nehru Medical College, Datta Meghe Institute of Higher Education and Research, Wardha, IND
| | - Shashank Agrawal
- Department of Medicine, Jawaharlal Nehru Medical College, Datta Meghe Institute of Higher Education and Research, Wardha, IND
| | - Harshita J
- Department of Medicine, Jawaharlal Nehru Medical College, Datta Meghe Institute of Higher Education and Research, Wardha, IND
| | - Ankita Sachdev
- Department of Medicine, Jawaharlal Nehru Medical College, Datta Meghe Institute of Higher Education and Research, Wardha, IND
| | - Yash Ghulaxe
- Department of Medicine, Jawaharlal Nehru Medical College, Datta Meghe Institute of Higher Education and Research, Wardha, IND
| | - Prayas Sarda
- Department of Medicine, Jawaharlal Nehru Medical College, Datta Meghe Institute of Higher Education and Research, Wardha, IND
| | - Jay Chavada
- Department of Medicine, Jawaharlal Nehru Medical College, Datta Meghe Institute of Higher Education and Research, Wardha, IND
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Glinge C, Rossetti S, Oestergaard LB, Stampe NK, Lynge TH, Skals R, Winkel BG, Lodder EM, Bezzina CR, Gislason G, Banner J, Behr ER, Torp-Pedersen C, Jabbari R, Tfelt-Hansen J. Risk of Sudden Infant Death Syndrome Among Siblings of Children Who Died of Sudden Infant Death Syndrome in Denmark. JAMA Netw Open 2023; 6:e2252724. [PMID: 36696110 DOI: 10.1001/jamanetworkopen.2022.52724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
IMPORTANCE Sudden infant death syndrome (SIDS) remains a leading cause of death during the first year of life. The etiology of SIDS is complex and remains largely unknown. OBJECTIVE To evaluate whether siblings of children who died of SIDS have a higher risk of SIDS compared with the general pediatric population. DESIGN, SETTING, AND PARTICIPANTS This register-based cohort study used Danish nationwide registers. Participants were all infants (<1 year) in Denmark between January 1, 1978, and December 31, 2016, including siblings of children who died of SIDS. Siblings were followed up from the index cases' date of SIDS, date of birth, or immigration, whichever came first, and until age 1 year, emigration, developing SIDS, death, or study end. The median (IQR) follow-up was 1 (1-1) year. Data analysis was conducted from January 2017 to October 2022. MAIN OUTCOMES AND MEASURES Standardized incidence ratios (SIRs) of SIDS were calculated with Poisson regression models relative to the general population. RESULTS In a population of 2 666 834 consecutive births (1 395 199 [52%] male), 1540 infants died of SIDS (median [IQR] age at SIDS, 3 [2-4] months) during a 39-year study period. A total of 2384 younger siblings (cases) to index cases (first sibling with SIDS) were identified. A higher rate of SIDS was observed among siblings compared with the general population, with SIRs of 4.27 (95% CI, 2.13-8.53) after adjustment for sex, age, and calendar year and of 3.50 (95% CI, 1.75-7.01) after further adjustment for mother's age (<29 years vs ≥29 years) and education (high school vs after high school). CONCLUSIONS AND RELEVANCE In this nationwide study, having a sibling who died of SIDS was associated with a 4-fold higher risk of SIDS compared with the general population. Shared genetic and/or environmental factors may contribute to the observed clustering of SIDS. The family history of SIDS should be considered when assessing SIDS risk in clinical settings. A multidisciplinary genetic evaluation of families with SIDS could provide additional evidence.
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Affiliation(s)
- Charlotte Glinge
- Department of Cardiology, The Heart Centre, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
- Department of Clinical and Experimental Cardiology, Heart Centre, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
| | - Sára Rossetti
- Department of Cardiology, The Heart Centre, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Louise Bruun Oestergaard
- Department of Cardiology, Copenhagen University Hospital-Herlev and Gentofte, Copenhagen, Denmark
- Department of Cardiology, Aalborg University Hospital, Aalborg, Denmark
| | - Niels Kjær Stampe
- Department of Cardiology, The Heart Centre, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Thomas Hadberg Lynge
- Department of Cardiology, The Heart Centre, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Regitze Skals
- Department of Cardiology, Aalborg University Hospital, Aalborg, Denmark
| | - Bo Gregers Winkel
- Department of Cardiology, The Heart Centre, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Elisabeth M Lodder
- Department of Clinical and Experimental Cardiology, Heart Centre, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
| | - Connie R Bezzina
- Department of Clinical and Experimental Cardiology, Heart Centre, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
| | - Gunnar Gislason
- Department of Cardiology, Copenhagen University Hospital-Herlev and Gentofte, Copenhagen, Denmark
- The Danish Heart Foundation, Copenhagen, Denmark
| | - Jytte Banner
- Department of Forensic Medicine, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Elijah R Behr
- Cardiology Clinical Academic Group, Cardiology Section, St George's, University of London, London, United Kingdom
- St George's University Hospitals NHS Foundation Trust, London, United Kingdom
- Mayo Clinic Healthcare, London, United Kingdom
| | - Christian Torp-Pedersen
- Department of Cardiology, Aalborg University Hospital, Aalborg, Denmark
- Department of Cardiology, North Zealand University Hospital, Hillerød, Denmark
- Department of Public Health, University of Copenhagen, Denmark
| | - Reza Jabbari
- Department of Cardiology, The Heart Centre, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Jacob Tfelt-Hansen
- Department of Cardiology, The Heart Centre, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
- Department of Forensic Medicine, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
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Developmental changes in cardiac expression of KCNQ1 and SCN5A spliceoforms: Implications for sudden unexpected infant death. Heart Rhythm 2021; 19:667-673. [PMID: 34843966 DOI: 10.1016/j.hrthm.2021.11.031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 10/27/2021] [Accepted: 11/19/2021] [Indexed: 11/24/2022]
Abstract
BACKGROUND Sudden unexpected infant death (SUID) occurs unpredictably and remains unexplained after scene investigation and autopsy. Approximately 1 in 7 cases of SUID can be related to a cardiac cause, and developmental regulation of cardiac ion channel genes may contribute to SUID. OBJECTIVE The goal of this study was to investigate the developmental changes in the spliceoforms of SCN5A and KCNQ1, 2 genes implicated in SUID. METHODS Using reverse transcription quantitative real-time polymerase chain reaction, we quantified expression of SCN5A (adult and fetal) and KCNQ1 (KCNQ1a and b) spliceoforms in 153 human cardiac tissue samples from decedents that succumbed to SUID ("unexplained") and other known causes of death ("explained noncardiac"). RESULTS There is a stepwise increase in the adult/fetal SCN5A spliceoform ratio from <2 months (4.55 ± 0.36; n = 51) through infancy and into adulthood (17.41 ± 3.33; n = 5). For KCNQ1, there is a decrease in the ratio of KCNQ1b to KCNQ1a between the <2-month (0.37 ± 0.02; n = 46) and the 2- to 4-month (0.28 ± 0.02; n = 52) age groups. When broken down by sex, race, or cause of death, there were no differences in SCN5A or KCNQ1 spliceoform expression, except for a higher ratio of KCNQ1b to KCNQ1a at 5-12 months of age for SUID females (0.40 ± 0.04; n = 9) than for males (0.25 ± 0.03; n = 6) and at <2 months of age for SUID white (0.42 ± 0.03; n = 19) than for black (0.33 ± 0.05; n = 9) infants. CONCLUSION This study documents the developmental changes in SCN5A and KCNQ1 spliceoforms in humans. Our data suggest that spliceoform expression ratios change significantly throughout the first year of life.
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Morris A, Elliott E, Jeffery H. Paediatrician experience of management of Sudden Unexpected Death in Infancy. J Forensic Leg Med 2021; 84:102268. [PMID: 34768190 DOI: 10.1016/j.jflm.2021.102268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Revised: 09/20/2021] [Accepted: 10/16/2021] [Indexed: 10/20/2022]
Abstract
Sudden unexpected death in infancy (SUDI) requires a thorough process of inquiry including a detailed history, death scene investigation and autopsy by appropriate and informed health professionals to identify aetiology. Paediatricians are required to conduct the medical, social and family history as well as provide support to the family for the approximately 45 deaths each year in New South Wales (NSW). The aim of this study is describe paediatricians' experience in conducting SUDI assessments with reference to current NSW Health policy and identify barriers to its implementation. METHODS Paediatricians in NSW who participate in the Australian Paediatric Surveillance Unit (APSU) were invited to complete a questionnaire requesting information about their knowledge and confidence in managing an infant presenting with SUDI, awareness and use of the NSW Health Policy Directive, and their own recommendations for management. A second questionnaire was completed by paediatricians who had attended a SUDI in the previous five years. RESULTS The first survey was completed by 234/524 (44%) NSW paediatricians. Half the respondents (118/234) were aware of the SUDI Policy Directive and of those 72/118 (61%) had read it. Few paediatricians (63/234) 27% had received education on the Policy Directive or about SUDI management 55/234 (24%). The second survey was completed by 33/36 (92%) who had attended a SUDI, of whom 29% had not used the history protocol within the Policy Directive. CONCLUSION Lack of awareness, perceived problems with the current Policy, and limited confidence suggests the model in NSW needs revision to meet international recommendations for best management and diagnosis and also supportive and preventive practices for parents.
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Affiliation(s)
- Anne Morris
- The University of Sydney, Faculty of Medicine and Health, The Sydney Children's Hospitals Network, Westmead, Sydney, New South Wales, Australia.
| | - Elizabeth Elliott
- The University of Sydney, Faculty of Medicine and Health, The Sydney Children's Hospitals Network, Westmead, Sydney, New South Wales, Australia
| | - Heather Jeffery
- Sydney School Public Health & Previously Clinical Academic Neonatologist, Royal Prince Alfred Hospital, Sydney, Australia
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Emergency care approach to sudden infant death syndrome. JOURNAL OF SURGERY AND MEDICINE 2021. [DOI: 10.28982/josam.867240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Mani I. Genome editing in cardiovascular diseases. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2021; 181:289-308. [PMID: 34127197 DOI: 10.1016/bs.pmbts.2021.01.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Genetic modification at the molecular level in somatic cells, germline, and animal models requires for different purposes, such as introducing desired mutation, deletion of alleles, and insertion of novel genes in the genome. Various genome-editing tools are available to accomplish these alterations, such as zinc finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs), and clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR associated (Cas) system. CRISPR-Cas system is an emerging technology, which is being used in biological and medical sciences, including in the cardiovascular field. It assists to identify the mechanism of various cardiovascular disease occurrence, such as hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM), and arrhythmogenic cardiomyopathy (ACM). Furthermore, it has been advantages to edit various genes simultaneously and can also be used to treat and prevent several human diseases. This chapter explores the use of the scientific and therapeutic potential of a CRISPR-Cas system to edit the various cardiovascular disease-associated genes to understand the pathways involved in disease progression and treatment.
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Affiliation(s)
- Indra Mani
- Department of Microbiology, Gargi College, University of Delhi, New Delhi, India.
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Sanford E, Jones MC, Brigger M, Hammer M, Giudugli L, Kingsmore SF, Dimmock D, Bainbridge MN. Postmortem diagnosis of PPA2-associated sudden cardiac death from dried blood spot in a neonate presenting with vocal cord paralysis. Cold Spring Harb Mol Case Stud 2020; 6:mcs.a005611. [PMID: 33028643 PMCID: PMC7552926 DOI: 10.1101/mcs.a005611] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 08/12/2020] [Indexed: 01/16/2023] Open
Abstract
Biallelic variants in inorganic pyrophosphatase 2 (PPA2) are known to cause infantile sudden cardiac failure (OMIM #617222), but relatively little is known about phenotypic variability of these patients prior to their death. We report a 5-wk-old male with bilateral vocal cord paralysis and hypertension who had a sudden unexpected cardiac death. Subsequently, molecular autopsy via whole-genome sequencing from newborn dried blood spot identified compound heterozygous mutations in PPA2, with a paternally inherited, pathogenic missense variant (c.514G > A; p.Glu172Lys) and a novel, maternally inherited missense variant of uncertain significance (c.442A > T; p.Thr148Ser). This report expands the presenting phenotype of patients with PPA2 variants. It also highlights the utility of dried blood spots for postmortem molecular diagnosis.
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Affiliation(s)
- Erica Sanford
- Rady Children's Institute of Genomic Medicine, University of California San Diego, La Jolla, California 92093, USA.,Division of Pediatric Critical Care Medicine, Department of Pediatrics, University of California San Diego, La Jolla, California 92093, USA
| | - Marilyn C Jones
- Division of Genetics, Department of Pediatrics, University of California San Diego, La Jolla, California 92093, USA
| | - Matthew Brigger
- Department of Otolaryngology, Rady Children's Hospital, San Diego, California 92123, USA
| | - Monia Hammer
- Rady Children's Institute of Genomic Medicine, University of California San Diego, La Jolla, California 92093, USA
| | - Lucia Giudugli
- Rady Children's Institute of Genomic Medicine, University of California San Diego, La Jolla, California 92093, USA
| | - Stephen F Kingsmore
- Rady Children's Institute of Genomic Medicine, University of California San Diego, La Jolla, California 92093, USA
| | - David Dimmock
- Rady Children's Institute of Genomic Medicine, University of California San Diego, La Jolla, California 92093, USA
| | - Matthew N Bainbridge
- Rady Children's Institute of Genomic Medicine, University of California San Diego, La Jolla, California 92093, USA
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Pang PD, Alsina KM, Cao S, Koushik AB, Wehrens XHT, Cooper TA. CRISPR -Mediated Expression of the Fetal Scn5a Isoform in Adult Mice Causes Conduction Defects and Arrhythmias. J Am Heart Assoc 2019; 7:e010393. [PMID: 30371314 PMCID: PMC6404881 DOI: 10.1161/jaha.118.010393] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Background The sodium channel, Nav1.5, encoded by SCN5A, undergoes developmentally regulated splicing from inclusion of exon 6A in the fetal heart to exon 6B in adults. These mutually exclusive exons differ in 7 amino acids altering the electrophysiological properties of the Nav1.5 channel. In myotonic dystrophy type 1, SCN5A is mis‐spliced such that the fetal pattern of exon 6A inclusion is detected in adult hearts. Cardiac manifestations of myotonic dystrophy type 1 include conduction defects and arrhythmias and are the second‐leading cause of death. Methods and Results This work aimed to determine the impact of SCN5A mis‐splicing on cardiac function. We used clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR‐associated protein 9 (Cas9) to delete Scn5a exon 6B in mice, thereby redirecting splicing toward exon 6A. These mice exhibit prolonged PR and QRS intervals, slowed conduction velocity, extended action potential duration, and are highly susceptible to arrhythmias. Conclusions Our findings highlight a nonmutational pathological mechanism of arrhythmias and conduction defects as a result of mis‐splicing of the predominant cardiac sodium channel. Animals homozygous for the deleted exon express only the fetal isoform and have more‐severe phenotypes than heterozygotes that also express the adult isoform. This observation is directly relevant to myotonic dystrophy type 1, and possibly pathological arrhythmias, in which individuals differ with regard to the ratios of the isoforms expressed.
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Affiliation(s)
- Paul D Pang
- 1 Department of Molecular Physiology & Biophysics Baylor College of Medicine Houston TX.,2 Department of Pathology & Immunology Baylor College of Medicine Houston TX.,3 Integrative Molecular and Biomedical Sciences Program Baylor College of Medicine Houston TX
| | - Katherina M Alsina
- 1 Department of Molecular Physiology & Biophysics Baylor College of Medicine Houston TX.,3 Integrative Molecular and Biomedical Sciences Program Baylor College of Medicine Houston TX
| | - Shuyi Cao
- 1 Department of Molecular Physiology & Biophysics Baylor College of Medicine Houston TX
| | - Amrita B Koushik
- 2 Department of Pathology & Immunology Baylor College of Medicine Houston TX
| | - Xander H T Wehrens
- 1 Department of Molecular Physiology & Biophysics Baylor College of Medicine Houston TX.,3 Integrative Molecular and Biomedical Sciences Program Baylor College of Medicine Houston TX.,5 Department of Medicine Baylor College of Medicine Houston TX.,6 Department of Pediatrics Baylor College of Medicine Houston TX.,7 Center for Space Medicine Baylor College of Medicine Houston TX.,8 Cardiovascular Research Institute Baylor College of Medicine Houston TX
| | - Thomas A Cooper
- 1 Department of Molecular Physiology & Biophysics Baylor College of Medicine Houston TX.,2 Department of Pathology & Immunology Baylor College of Medicine Houston TX.,3 Integrative Molecular and Biomedical Sciences Program Baylor College of Medicine Houston TX.,4 Department of Molecular & Cellular Biology Baylor College of Medicine Houston TX.,8 Cardiovascular Research Institute Baylor College of Medicine Houston TX
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Verkerk AO, Lodder EM, Wilders R. Aquaporin Channels in the Heart-Physiology and Pathophysiology. Int J Mol Sci 2019; 20:ijms20082039. [PMID: 31027200 PMCID: PMC6514906 DOI: 10.3390/ijms20082039] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 04/19/2019] [Accepted: 04/23/2019] [Indexed: 12/11/2022] Open
Abstract
Mammalian aquaporins (AQPs) are transmembrane channels expressed in a large variety of cells and tissues throughout the body. They are known as water channels, but they also facilitate the transport of small solutes, gasses, and monovalent cations. To date, 13 different AQPs, encoded by the genes AQP0–AQP12, have been identified in mammals, which regulate various important biological functions in kidney, brain, lung, digestive system, eye, and skin. Consequently, dysfunction of AQPs is involved in a wide variety of disorders. AQPs are also present in the heart, even with a specific distribution pattern in cardiomyocytes, but whether their presence is essential for proper (electro)physiological cardiac function has not intensively been studied. This review summarizes recent findings and highlights the involvement of AQPs in normal and pathological cardiac function. We conclude that AQPs are at least implicated in proper cardiac water homeostasis and energy balance as well as heart failure and arsenic cardiotoxicity. However, this review also demonstrates that many effects of cardiac AQPs, especially on excitation-contraction coupling processes, are virtually unexplored.
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Affiliation(s)
- Arie O Verkerk
- Department of Medical Biology, Amsterdam University Medical Centers, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands.
- Department of Experimental Cardiology, Amsterdam University Medical Centers, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands.
| | - Elisabeth M Lodder
- Department of Experimental Cardiology, Amsterdam University Medical Centers, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands.
| | - Ronald Wilders
- Department of Medical Biology, Amsterdam University Medical Centers, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands.
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Sarquella-Brugada G, Cesar S, Zambrano MD, Fernandez-Falgueras A, Fiol V, Iglesias A, Torres F, Garcia-Algar O, Arbelo E, Brugada J, Brugada R, Campuzano O. Electrocardiographic Assessment and Genetic Analysis in Neonates: a Current Topic of Discussion. Curr Cardiol Rev 2019; 15:30-37. [PMID: 30210005 PMCID: PMC6367699 DOI: 10.2174/1573403x14666180913114806] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 09/10/2018] [Accepted: 09/11/2018] [Indexed: 12/30/2022] Open
Abstract
Background: Sudden death of a newborn is a rare entity, which may be caused by genetic cardiac arrhythmias. Among these diseases, Long QT syndrome is the most prevalent arrhythmia in neonates, but other diseases such as Brugada syndrome, Short QT syndrome and Catecholaminergic Polymorphic Ventricular Tachycardia also cause sudden death in infants. All these entities are charac-terized by well-known alterations in the electrocardiogram and the first symptom of the disease may be an unexpected death. Despite the low prevalence of these diseases, the performance of an electro-cardiogram in the first hours or days after birth could help identify these electrical disruptions and adopt preventive measures. In recent years, there has been an important impulse by some experts in the scientific community towards the initiation of a newborn electrocardiogram-screening program, for the detection of these electrocardiographic abnormalities. In addition, the use of genetic analysis in neonates could identify the cause of these heart alterations. Identification of relatives carrying the ge-netic alteration associated with the disease allows adoption of measures to prevent lethal episodes. Conclusion: Recent technological advances enable a comprehensive genetic screening of a large number of genes in a cost-effective way. However, the interpretation of genetic data and its translation into clinical practice are the main challenges for cardiologists and geneticists. However, there is im-portant controversy as to the clinical value, and cost-effectiveness of the use of electrocardiogram as well as of genetic testing to detect these cases. Our review focuses on these current matters of argue.
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Affiliation(s)
- Georgia Sarquella-Brugada
- Arrhythmias Unit, Hospital Sant Joan de Deu, University of Barcelona, Barcelona, Spain.,Medical Science Department, School of Medicine, University of Girona, Girona, Spain
| | - Sergi Cesar
- Arrhythmias Unit, Hospital Sant Joan de Deu, University of Barcelona, Barcelona, Spain
| | | | | | - Victoria Fiol
- Arrhythmias Unit, Hospital Sant Joan de Deu, University of Barcelona, Barcelona, Spain
| | - Anna Iglesias
- Cardiovascular Genetics Center, University of Girona- IDIBGI, Girona, Spain.,Centro Investigación Biomédica Red Enfermedades Cardiovasculares (CIBERCV), Girona, Spain
| | - Francesc Torres
- GRIE, Neonatology Unit, Hospital Clinic-Maternitat, IDIBAPS, BCNatal, Barcelona, Spain
| | - Oscar Garcia-Algar
- GRIE, Neonatology Unit, Hospital Clinic-Maternitat, IDIBAPS, BCNatal, Barcelona, Spain
| | - Elena Arbelo
- Centro Investigación Biomédica Red Enfermedades Cardiovasculares (CIBERCV), Girona, Spain.,Arrhythmias Unit, Hospital Clinic, University of Barcelona, Barcelona, Spain
| | - Josep Brugada
- Arrhythmias Unit, Hospital Sant Joan de Deu, University of Barcelona, Barcelona, Spain.,Centro Investigación Biomédica Red Enfermedades Cardiovasculares (CIBERCV), Girona, Spain.,Arrhythmias Unit, Hospital Clinic, University of Barcelona, Barcelona, Spain
| | - Ramon Brugada
- Medical Science Department, School of Medicine, University of Girona, Girona, Spain.,Cardiovascular Genetics Center, University of Girona- IDIBGI, Girona, Spain.,Centro Investigación Biomédica Red Enfermedades Cardiovasculares (CIBERCV), Girona, Spain.,Cardiology Service, Hospital Josep Trueta, University of Girona, Girona. Spain
| | - Oscar Campuzano
- Medical Science Department, School of Medicine, University of Girona, Girona, Spain.,Cardiovascular Genetics Center, University of Girona- IDIBGI, Girona, Spain.,Centro Investigación Biomédica Red Enfermedades Cardiovasculares (CIBERCV), Girona, Spain
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11
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Crotti L, Ghidoni A, Dagradi F. Genetics of Adult and Fetal Forms of Long QT Syndrome. GENETIC CAUSES OF CARDIAC DISEASE 2019. [DOI: 10.1007/978-3-030-27371-2_1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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12
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Functional significance of channelopathy gene variants in unexplained death. Forensic Sci Med Pathol 2018; 15:437-444. [DOI: 10.1007/s12024-018-0063-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/20/2018] [Indexed: 02/06/2023]
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Verkerk AO, Amin AS, Remme CA. Disease Modifiers of Inherited SCN5A Channelopathy. Front Cardiovasc Med 2018; 5:137. [PMID: 30327767 PMCID: PMC6174200 DOI: 10.3389/fcvm.2018.00137] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 09/10/2018] [Indexed: 12/19/2022] Open
Abstract
To date, a large number of mutations in SCN5A, the gene encoding the pore-forming α-subunit of the primary cardiac Na+ channel (NaV1.5), have been found in patients presenting with a wide range of ECG abnormalities and cardiac syndromes. Although these mutations all affect the same NaV1.5 channel, the associated cardiac syndromes each display distinct phenotypical and biophysical characteristics. Variable disease expressivity has also been reported, where one particular mutation in SCN5A may lead to either one particular symptom, a range of various clinical signs, or no symptoms at all, even within one single family. Additionally, disease severity may vary considerably between patients carrying the same mutation. The exact reasons are unknown, but evidence is increasing that various cardiac and non-cardiac conditions can influence the expressivity and severity of inherited SCN5A channelopathies. In this review, we provide a summary of identified disease entities caused by SCN5A mutations, and give an overview of co-morbidities and other (non)-genetic factors which may modify SCN5A channelopathies. A comprehensive knowledge of these modulatory factors is not only essential for a complete understanding of the diverse clinical phenotypes associated with SCN5A mutations, but also for successful development of effective risk stratification and (alternative) treatment paradigms.
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Affiliation(s)
- Arie O Verkerk
- Department of Clinical and Experimental Cardiology, Heart Centre, Academic Medical Center, Amsterdam, Netherlands.,Department of Medical Biology, Academic Medical Center, Amsterdam, Netherlands
| | - Ahmad S Amin
- Department of Clinical and Experimental Cardiology, Heart Centre, Academic Medical Center, Amsterdam, Netherlands
| | - Carol Ann Remme
- Department of Clinical and Experimental Cardiology, Heart Centre, Academic Medical Center, Amsterdam, Netherlands
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Son MJ, Kim MK, Yang KM, Choi BH, Lee BW, Yoo SH. Retrospective Genetic Analysis of 200 Cases of Sudden Infant Death Syndrome and Its Relationship with Long QT Syndrome in Korea. J Korean Med Sci 2018; 33:e200. [PMID: 30079003 PMCID: PMC6070466 DOI: 10.3346/jkms.2018.33.e200] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 05/16/2018] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND There has been a campaign by the National Education on Sleeping Habits and Living Environment, to reduce the incidence of sudden infant death syndrome (SIDS). However, more than 100 infants die suddenly and unexplainably before the age of 1 year in Korea. Long QT syndrome (LQTS), an inheritable cardiac disease, has been reported to likely be associated with up to 14% of SIDS cases. However, genetic studies of the association between SIDS and LQTS have not yet been conducted in Korea. METHODS We conducted genetic analysis using genomic DNA extracted from paraffin-embedded tissue blocks from 200 SIDS cases autopsied between 2005 and 2013. We analyzed the following genetic mutations associated with LQTS, KCNQ1, SCN5A, KCNE1, KCNE2, KCNJ2, and CAV3. RESULTS Of the 200 SIDS cases, 58% involved male infants (116 male and 84 female infants, respectively), the mean age was 140 days (median, 107 days; range, 24-270 days), and they were all of Asian-Korean ethnicity. SIDS IA category criteria comprised 45 cases (22.5%) while the rest were SIDS IB. Fifteen infants (7.5%) had R1193Q in SCN5A, of doubtful pathogenicity, and no pathogenic LQTS variants were observed. CONCLUSION This genetic investigation of LQTS in SIDS showed a low diagnostic yield. These findings suggest that LQTS molecular autopsy could be cautiously conducted in selected cases with family involvement to improve the available genetic counseling information. Meanwhile, a national SIDS registry should be established to document and evaluate the genetic risk of SIDS in Korea.
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Affiliation(s)
- Min-Jeong Son
- Department of Forensic Medicine and Institute of Forensic Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Min-Kyoung Kim
- Department of Forensic Medicine and Institute of Forensic Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Kyung-moo Yang
- Division of Forensic Medicine, National Forensic Service, Seoul, Korea
| | - Byung-Ha Choi
- Medical Examiner's Office, National Forensic Service, Wonju, Korea
| | - Bong Woo Lee
- Medical Examiner's Office, National Forensic Service, Wonju, Korea
| | - Seong Ho Yoo
- Department of Forensic Medicine and Institute of Forensic Medicine, Seoul National University College of Medicine, Seoul, Korea
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15
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Denti F, Bentzen BH, Wojciak J, Thomsen NM, Scheinman M, Schmitt N. Multiple genetic variations in sodium channel subunits in a case of sudden infant death syndrome. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2018; 41:620-626. [PMID: 29572929 DOI: 10.1111/pace.13328] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Revised: 02/15/2018] [Accepted: 02/25/2018] [Indexed: 12/20/2022]
Abstract
BACKGROUND Dysfunction of NaV 1.5 encoded by SCN5A accounts for approximately half of the channelopathic SIDS cases. We investigated the functional effect of two gene variants identified in the same patient, one in SCN5A and one in SCN1Bb. The aim of the study was to risk stratify the proband's family. METHODS The family was referred for cardiovascular genetic evaluation to assess familial risk of cardiac disease. Functional analysis of the identified variants was performed with patch-clamp electrophysiology in HEK293 cells. RESULTS A 16-month-old healthy boy died suddenly in the context of nonspecific illness and possible fever. Postmortem genetic testing revealed variants in the SCN5A and SCN1Bb genes. The proband's father carries the same variants but is asymptomatic. Electrophysiological analysis of the NaV 1.5_1281X truncation revealed complete loss-of-function of the channel. Coexpression of NaV 1.5 with NaV β1b significantly increased INa density when compared to NaV 1.5 alone. The NaV β1b _V268I variant abolished this INa density increase. Moreover, it shifted the activation curve toward more depolarized potentials. CONCLUSIONS Genetic variation of both sodium channel and its modifiers may contribute to sudden unexplained death in childhood. However, the asymptomatic father suggests that genetic variation of these genes is not sufficient to cause sudden death or clinically detectable SCN5A phenotypes.
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Affiliation(s)
- Federico Denti
- Danish National Research Foundation Centre for Cardiac Arrhythmia and Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Bo Hjorth Bentzen
- Danish National Research Foundation Centre for Cardiac Arrhythmia and Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Julianne Wojciak
- Department of Medicine, University of California San Francisco, San Francisco, CA, USA
| | - Nancy Mutsaers Thomsen
- Danish National Research Foundation Centre for Cardiac Arrhythmia and Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Melvin Scheinman
- Department of Medicine, University of California San Francisco, San Francisco, CA, USA
| | - Nicole Schmitt
- Danish National Research Foundation Centre for Cardiac Arrhythmia and Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
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Dewar LJ, Alcaide M, Fornika D, D’Amato L, Shafaatalab S, Stevens CM, Balachandra T, Phillips SM, Sanatani S, Morin RD, Tibbits GF. Investigating the Genetic Causes of Sudden Unexpected Death in Children Through Targeted Next-Generation Sequencing Analysis. ACTA ACUST UNITED AC 2017; 10:CIRCGENETICS.116.001738. [DOI: 10.1161/circgenetics.116.001738] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Accepted: 04/25/2017] [Indexed: 12/27/2022]
Abstract
Background—
Inherited arrhythmia syndromes are responsible for a significant portion of autopsy-negative sudden unexpected death (SUD) cases, but molecular autopsy used to identify potentially causal variants is not routinely included in SUD investigations. We collaborated with a medical examiner's office to assist in finding a diagnosis for their autopsy-negative child SUD cases.
Methods and Results—
191 child SUD cases (<5 years of age) were selected for analyses. Our next generation sequencing panel incorporated 38 inherited arrhythmia syndrome candidate genes and another 33 genes not previously investigated for variants that may underlie SUDY pathophysiology. Overall, we identified 11 potentially causal disease-associated variants in 12 cases, for an overall yield of 6.3%. We also identified 31 variants of uncertain significance in 36 cases and 16 novel variants predicted to be pathogenic in silico in 15 cases. The disease-associated variants were reported to the medical examiner to notify surviving relatives and recommend clinical assessment.
Conclusions—
We have identified variants that may assist in the diagnosis of at least 6.3% of autopsy-negative child SUD cases and reduce risk of future SUD in surviving relatives. We recommend a cautious approach to variant interpretation. We also suggest inclusion of cardiomyopathy genes as well as other candidate SUD genes in molecular autopsy analyses.
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Affiliation(s)
- Laura J. Dewar
- From the Departments of Biomedical Physiology and Kinesiology (L.J.D., S.S., C.M.S., G.F.T.) and Molecular Biology and Biochemistry (M.A., D.F., L.D., C.M.S., R.D.M., G.F.T.), Simon Fraser University, Burnaby, British Columbia, Canada; BC Children’s Hospital Research Institute, Vancouver, Canada (L.J.D., S.S., C.M.S., G.F.T.); Department of Pathology, Faculty of Medicine, University of Manitoba, Winnipeg, Canada (T.B., S.M.P.); and Division of Pediatric Cardiology, Department of Pediatrics, British
| | - Miguel Alcaide
- From the Departments of Biomedical Physiology and Kinesiology (L.J.D., S.S., C.M.S., G.F.T.) and Molecular Biology and Biochemistry (M.A., D.F., L.D., C.M.S., R.D.M., G.F.T.), Simon Fraser University, Burnaby, British Columbia, Canada; BC Children’s Hospital Research Institute, Vancouver, Canada (L.J.D., S.S., C.M.S., G.F.T.); Department of Pathology, Faculty of Medicine, University of Manitoba, Winnipeg, Canada (T.B., S.M.P.); and Division of Pediatric Cardiology, Department of Pediatrics, British
| | - Daniel Fornika
- From the Departments of Biomedical Physiology and Kinesiology (L.J.D., S.S., C.M.S., G.F.T.) and Molecular Biology and Biochemistry (M.A., D.F., L.D., C.M.S., R.D.M., G.F.T.), Simon Fraser University, Burnaby, British Columbia, Canada; BC Children’s Hospital Research Institute, Vancouver, Canada (L.J.D., S.S., C.M.S., G.F.T.); Department of Pathology, Faculty of Medicine, University of Manitoba, Winnipeg, Canada (T.B., S.M.P.); and Division of Pediatric Cardiology, Department of Pediatrics, British
| | - Luisa D’Amato
- From the Departments of Biomedical Physiology and Kinesiology (L.J.D., S.S., C.M.S., G.F.T.) and Molecular Biology and Biochemistry (M.A., D.F., L.D., C.M.S., R.D.M., G.F.T.), Simon Fraser University, Burnaby, British Columbia, Canada; BC Children’s Hospital Research Institute, Vancouver, Canada (L.J.D., S.S., C.M.S., G.F.T.); Department of Pathology, Faculty of Medicine, University of Manitoba, Winnipeg, Canada (T.B., S.M.P.); and Division of Pediatric Cardiology, Department of Pediatrics, British
| | - Sanam Shafaatalab
- From the Departments of Biomedical Physiology and Kinesiology (L.J.D., S.S., C.M.S., G.F.T.) and Molecular Biology and Biochemistry (M.A., D.F., L.D., C.M.S., R.D.M., G.F.T.), Simon Fraser University, Burnaby, British Columbia, Canada; BC Children’s Hospital Research Institute, Vancouver, Canada (L.J.D., S.S., C.M.S., G.F.T.); Department of Pathology, Faculty of Medicine, University of Manitoba, Winnipeg, Canada (T.B., S.M.P.); and Division of Pediatric Cardiology, Department of Pediatrics, British
| | - Charles M. Stevens
- From the Departments of Biomedical Physiology and Kinesiology (L.J.D., S.S., C.M.S., G.F.T.) and Molecular Biology and Biochemistry (M.A., D.F., L.D., C.M.S., R.D.M., G.F.T.), Simon Fraser University, Burnaby, British Columbia, Canada; BC Children’s Hospital Research Institute, Vancouver, Canada (L.J.D., S.S., C.M.S., G.F.T.); Department of Pathology, Faculty of Medicine, University of Manitoba, Winnipeg, Canada (T.B., S.M.P.); and Division of Pediatric Cardiology, Department of Pediatrics, British
| | - Thambirajah Balachandra
- From the Departments of Biomedical Physiology and Kinesiology (L.J.D., S.S., C.M.S., G.F.T.) and Molecular Biology and Biochemistry (M.A., D.F., L.D., C.M.S., R.D.M., G.F.T.), Simon Fraser University, Burnaby, British Columbia, Canada; BC Children’s Hospital Research Institute, Vancouver, Canada (L.J.D., S.S., C.M.S., G.F.T.); Department of Pathology, Faculty of Medicine, University of Manitoba, Winnipeg, Canada (T.B., S.M.P.); and Division of Pediatric Cardiology, Department of Pediatrics, British
| | - Susan M. Phillips
- From the Departments of Biomedical Physiology and Kinesiology (L.J.D., S.S., C.M.S., G.F.T.) and Molecular Biology and Biochemistry (M.A., D.F., L.D., C.M.S., R.D.M., G.F.T.), Simon Fraser University, Burnaby, British Columbia, Canada; BC Children’s Hospital Research Institute, Vancouver, Canada (L.J.D., S.S., C.M.S., G.F.T.); Department of Pathology, Faculty of Medicine, University of Manitoba, Winnipeg, Canada (T.B., S.M.P.); and Division of Pediatric Cardiology, Department of Pediatrics, British
| | - Shubhayan Sanatani
- From the Departments of Biomedical Physiology and Kinesiology (L.J.D., S.S., C.M.S., G.F.T.) and Molecular Biology and Biochemistry (M.A., D.F., L.D., C.M.S., R.D.M., G.F.T.), Simon Fraser University, Burnaby, British Columbia, Canada; BC Children’s Hospital Research Institute, Vancouver, Canada (L.J.D., S.S., C.M.S., G.F.T.); Department of Pathology, Faculty of Medicine, University of Manitoba, Winnipeg, Canada (T.B., S.M.P.); and Division of Pediatric Cardiology, Department of Pediatrics, British
| | - Ryan D. Morin
- From the Departments of Biomedical Physiology and Kinesiology (L.J.D., S.S., C.M.S., G.F.T.) and Molecular Biology and Biochemistry (M.A., D.F., L.D., C.M.S., R.D.M., G.F.T.), Simon Fraser University, Burnaby, British Columbia, Canada; BC Children’s Hospital Research Institute, Vancouver, Canada (L.J.D., S.S., C.M.S., G.F.T.); Department of Pathology, Faculty of Medicine, University of Manitoba, Winnipeg, Canada (T.B., S.M.P.); and Division of Pediatric Cardiology, Department of Pediatrics, British
| | - Glen F. Tibbits
- From the Departments of Biomedical Physiology and Kinesiology (L.J.D., S.S., C.M.S., G.F.T.) and Molecular Biology and Biochemistry (M.A., D.F., L.D., C.M.S., R.D.M., G.F.T.), Simon Fraser University, Burnaby, British Columbia, Canada; BC Children’s Hospital Research Institute, Vancouver, Canada (L.J.D., S.S., C.M.S., G.F.T.); Department of Pathology, Faculty of Medicine, University of Manitoba, Winnipeg, Canada (T.B., S.M.P.); and Division of Pediatric Cardiology, Department of Pediatrics, British
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17
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Gando I, Morganstein J, Jana K, McDonald TV, Tang Y, Coetzee WA. Infant sudden death: Mutations responsible for impaired Nav1.5 channel trafficking and function. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2017; 40:703-712. [PMID: 28370132 DOI: 10.1111/pace.13087] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 03/20/2017] [Accepted: 03/27/2017] [Indexed: 01/10/2023]
Abstract
BACKGROUND Two genetic variants in SCN5A, encoding the Nav1.5 Na+ channel α-subunit, were found in a 5-month-old girl who died suddenly in her sleep. The first variant is a missense mutation, resulting in an amino acid change (Q1832E), which has been described (but not characterized) in a patient with Brugada syndrome. The second is a nonsense mutation that produces a premature stop codon and a C-terminal truncation (R1944Δ). METHODS AND RESULTS To investigate their functional relevance with patch clamp experiments in transfected HEK-293 cells. The Q1832E mutation drastically reduced Nav1.5 current density. The R1944Δ C-terminal truncation had negligible effects on Nav1.5 current density. Neither of the mutations affected the voltage dependence of steady activation and inactivation or influenced the late Na+ current or the recovery from inactivation. Biochemical and immunofluorescent approaches demonstrated that the Q1832E mutation caused severe trafficking defects. Polymerase chain reaction cloning and sequencing the victim's genomic DNA allowed us to determine that the two variants were in trans. We investigated the functional consequences by coexpressing Nav1.5(Q1832E) and Nav1.5(R1944Δ), which led to a significantly reduced current amplitude relative to wild-type. CONCLUSIONS These sudden infant death syndrome (SIDS)-related variants caused a severely dysfunctional Nav1.5 channel, which was mainly due to trafficking defects caused by the Q1832E mutation. The decreased current density is likely to be a major contributing factor to arrhythmogenesis in Brugada syndrome and the sudden death of this SIDS victim.
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Affiliation(s)
- Ivan Gando
- Pediatrics, NYU School of Medicine, New York, NY
| | | | - Kundan Jana
- Pediatrics, NYU School of Medicine, New York, NY
| | - Thomas V McDonald
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY
| | - Yingying Tang
- Molecular Genetics Laboratory, Office of Chief Medical Examiner, New York, NY
| | - William A Coetzee
- Pediatrics, NYU School of Medicine, New York, NY.,Physiology & Neuroscience, NYU School of Medicine, New York, NY.,Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, NY
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18
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Psaila K, Foster JP, Pulbrook N, Jeffery HE. Infant pacifiers for reduction in risk of sudden infant death syndrome. Cochrane Database Syst Rev 2017; 4:CD011147. [PMID: 28378502 PMCID: PMC6478106 DOI: 10.1002/14651858.cd011147.pub2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND Sudden infant death syndrome (SIDS) has been most recently defined as the sudden unexpected death of an infant less than one year of age, with onset of the fatal episode apparently occurring during sleep, that remains unexplained after a thorough investigation, including the performance of a complete autopsy and a review of the circumstances of death and clinical history. Despite the success of several prevention campaigns, SIDS remains a leading cause of infant mortality. In 1994, a 'triple risk model' for SIDS was proposed that described SIDS as an event that results from the intersection of three factors: a vulnerable infant; a critical development period in homeostatic control (age related); and an exogenous stressor. The association between pacifier (dummy) use and reduced incidence of SIDS has been shown in epidemiological studies since the early 1990s. Pacifier use, given its low cost, might be a cost-effective intervention for SIDS prevention if it is confirmed effective in randomised controlled trials. OBJECTIVES To determine whether the use of pacifiers during sleep versus no pacifier during sleep reduces the risk of SIDS. SEARCH METHODS We used the standard search strategy of the Cochrane Neonatal Review Group to search the Cochrane Central Register of Controlled Trials (CENTRAL 2016, Issue 2), MEDLINE via PubMed, Embase, and CINAHL to 16 March 2016. We also searched clinical trials databases, conference proceedings, and the reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials. SELECTION CRITERIA Published and unpublished controlled trials using random and quasi-random allocations of infants born at term and at preterm (less than 37 weeks' gestation) or with low birth weight (< 2500 g). Infants must have been randomised by one month' postmenstrual age. We planned to include studies reported only by abstracts, and cluster and cross-over randomised trials. DATA COLLECTION AND ANALYSIS Two review authors independently reviewed studies from searches. We found no eligible studies. MAIN RESULTS We identified no randomised controlled trials examining infant pacifiers for reduction in risk of SIDS. AUTHORS' CONCLUSIONS We found no randomised control trial evidence on which to support or refute the use of pacifiers for the prevention of SIDS.
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Affiliation(s)
- Kim Psaila
- Western Sydney UniversitySchool of Nursing and MidwiferyPenrithDCAustralia
| | - Jann P Foster
- Western Sydney UniversitySchool of Nursing and MidwiferyPenrith DCAustralia
- University of SydneySydney Nursing School/Central Clinical School, Discipline of Obstetrics, Gynaecology and NeonatologySydneyAustralia
- Ingham Research InstituteLiverpoolNSWAustralia
| | - Neil Pulbrook
- Liverpool HospitalNewborn CareElizabeth StreetLiverpoolAustralia2170
| | - Heather E Jeffery
- University of SydneySydney School of Public HealthSydneyNSWAustralia2050
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19
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Chadda KR, Jeevaratnam K, Lei M, Huang CLH. Sodium channel biophysics, late sodium current and genetic arrhythmic syndromes. Pflugers Arch 2017; 469:629-641. [PMID: 28265756 PMCID: PMC5438422 DOI: 10.1007/s00424-017-1959-1] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2017] [Accepted: 02/14/2017] [Indexed: 12/11/2022]
Abstract
Arrhythmias arise from breakdown of orderly action potential (AP) activation, propagation and recovery driven by interactive opening and closing of successive voltage-gated ion channels, in which one or more Na+ current components play critical parts. Early peak, Na+ currents (INa) reflecting channel activation drive the AP upstroke central to cellular activation and its propagation. Sustained late Na+ currents (INa-L) include contributions from a component with a delayed inactivation timecourse influencing AP duration (APD) and refractoriness, potentially causing pro-arrhythmic phenotypes. The magnitude of INa-L can be analysed through overlaps or otherwise in the overall voltage dependences of the steady-state properties and kinetics of activation and inactivation of the Na+ conductance. This was useful in analysing repetitive firing associated with paramyotonia congenita in skeletal muscle. Similarly, genetic cardiac Na+ channel abnormalities increasing INa-L are implicated in triggering phenomena of automaticity, early and delayed afterdepolarisations and arrhythmic substrate. This review illustrates a wide range of situations that may accentuate INa-L. These include (1) overlaps between steady-state activation and inactivation increasing window current, (2) kinetic deficiencies in Na+ channel inactivation leading to bursting phenomena associated with repetitive channel openings and (3) non-equilibrium gating processes causing channel re-opening due to more rapid recoveries from inactivation. All these biophysical possibilities were identified in a selection of abnormal human SCN5A genotypes. The latter presented as a broad range of clinical arrhythmic phenotypes, for which effective therapeutic intervention would require specific identification and targeting of the diverse electrophysiological abnormalities underlying their increased INa-L.
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Affiliation(s)
- Karan R Chadda
- Faculty of Health and Medical Sciences, University of Surrey, VSM Building, Guildford, GU2 7AL, UK
- Physiological Laboratory, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK
| | - Kamalan Jeevaratnam
- Faculty of Health and Medical Sciences, University of Surrey, VSM Building, Guildford, GU2 7AL, UK
- School of Medicine, Perdana University-Royal College of Surgeons Ireland, 43400, Serdang, Selangor Darul Ehsan, Malaysia
| | - Ming Lei
- Department of Pharmacology, University of Oxford, Oxford, OX1 3QT, UK
| | - Christopher L-H Huang
- Physiological Laboratory, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK.
- Department of Biochemistry, University of Cambridge, Hopkins Building, Cambridge, CB2 1QW, UK.
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20
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Aromolaran AS, Chahine M, Boutjdir M. Regulation of Cardiac Voltage-Gated Sodium Channel by Kinases: Roles of Protein Kinases A and C. Handb Exp Pharmacol 2017; 246:161-184. [PMID: 29032483 DOI: 10.1007/164_2017_53] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
In the heart, voltage-gated sodium (Nav) channel (Nav1.5) is defined by its pore-forming α-subunit and its auxiliary β-subunits, both of which are important for its critical contribution to the initiation and maintenance of the cardiac action potential (AP) that underlie normal heart rhythm. The physiological relevance of Nav1.5 is further marked by the fact that inherited or congenital mutations in Nav1.5 channel gene SCN5A lead to altered functional expression (including expression, trafficking, and current density), and are generally manifested in the form of distinct cardiac arrhythmic events, epilepsy, neuropathic pain, migraine, and neuromuscular disorders. However, despite significant advances in defining the pathophysiology of Nav1.5, the molecular mechanisms that underlie its regulation and contribution to cardiac disorders are poorly understood. It is rapidly becoming evident that the functional expression (localization, trafficking and gating) of Nav1.5 may be under modulation by post-translational modifications that are associated with phosphorylation. We review here the molecular basis of cardiac Na channel regulation by kinases (PKA and PKC) and the resulting functional consequences. Specifically, we discuss: (1) recent literature on the structural, molecular, and functional properties of cardiac Nav1.5 channels; (2) how these properties may be altered by phosphorylation in disease states underlain by congenital mutations in Nav1.5 channel and/or subunits such as long QT and Brugada syndromes. Our expectation is that understanding the roles of these distinct and complex phosphorylation processes on the functional expression of Nav1.5 is likely to provide crucial mechanistic insights into Na channel associated arrhythmogenic events and will facilitate the development of novel therapeutic strategies.
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Affiliation(s)
- Ademuyiwa S Aromolaran
- Cardiovascular Research Program, VA New York Harbor Healthcare System, Brooklyn, NY, USA
- Departments of Medicine, Cell Biology and Pharmacology, State University of New York Downstate Medical Center, Brooklyn, NY, USA
| | - Mohamed Chahine
- CERVO Brain Research Center, Institut Universitaire en Santé Mentale de Québec, Quebec City, QC, Canada
- Department of Medicine, Université Laval, Quebec City, QC, Canada
| | - Mohamed Boutjdir
- Cardiovascular Research Program, VA New York Harbor Healthcare System, Brooklyn, NY, USA.
- Departments of Medicine, Cell Biology and Pharmacology, State University of New York Downstate Medical Center, Brooklyn, NY, USA.
- Department of Medicine, New York University School of Medicine, New York, NY, USA.
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Abstract
Cardiac arrhythmias can follow disruption of the normal cellular electrophysiological processes underlying excitable activity and their tissue propagation as coherent wavefronts from the primary sinoatrial node pacemaker, through the atria, conducting structures and ventricular myocardium. These physiological events are driven by interacting, voltage-dependent, processes of activation, inactivation, and recovery in the ion channels present in cardiomyocyte membranes. Generation and conduction of these events are further modulated by intracellular Ca2+ homeostasis, and metabolic and structural change. This review describes experimental studies on murine models for known clinical arrhythmic conditions in which these mechanisms were modified by genetic, physiological, or pharmacological manipulation. These exemplars yielded molecular, physiological, and structural phenotypes often directly translatable to their corresponding clinical conditions, which could be investigated at the molecular, cellular, tissue, organ, and whole animal levels. Arrhythmogenesis could be explored during normal pacing activity, regular stimulation, following imposed extra-stimuli, or during progressively incremented steady pacing frequencies. Arrhythmic substrate was identified with temporal and spatial functional heterogeneities predisposing to reentrant excitation phenomena. These could arise from abnormalities in cardiac pacing function, tissue electrical connectivity, and cellular excitation and recovery. Triggering events during or following recovery from action potential excitation could thereby lead to sustained arrhythmia. These surface membrane processes were modified by alterations in cellular Ca2+ homeostasis and energetics, as well as cellular and tissue structural change. Study of murine systems thus offers major insights into both our understanding of normal cardiac activity and its propagation, and their relationship to mechanisms generating clinical arrhythmias.
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Affiliation(s)
- Christopher L-H Huang
- Physiological Laboratory and the Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
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22
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Biallelic PPA2 Mutations Cause Sudden Unexpected Cardiac Arrest in Infancy. Am J Hum Genet 2016; 99:666-673. [PMID: 27523598 DOI: 10.1016/j.ajhg.2016.06.021] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 06/22/2016] [Indexed: 11/21/2022] Open
Abstract
Sudden unexpected death in infancy occurs in apparently healthy infants and remains largely unexplained despite thorough investigation. The vast majority of cases are sporadic. Here we report seven individuals from three families affected by sudden and unexpected cardiac arrest between 4 and 20 months of age. Whole-exome sequencing revealed compound heterozygous missense mutations in PPA2 in affected infants of each family. PPA2 encodes the mitochondrial pyrophosphatase, which hydrolyzes inorganic pyrophosphate into two phosphates. This is an essential activity for many biosynthetic reactions and for energy metabolism of the cell. We show that deletion of the orthologous gene in yeast (ppa2Δ) compromises cell viability due to the loss of mitochondria. Expression of wild-type human PPA2, but not PPA2 containing the mutations identified in affected individuals, preserves mitochondrial function in ppa2Δ yeast. Using a regulatable (doxycycline-repressible) gene expression system, we found that the pathogenic PPA2 mutations rapidly inactivate the mitochondrial energy transducing system and prevent the maintenance of a sufficient electrical potential across the inner membrane, which explains the subsequent disappearance of mitochondria from the mutant yeast cells. Altogether these data demonstrate that PPA2 is an essential gene in yeast and that biallelic mutations in PPA2 cause a mitochondrial disease leading to sudden cardiac arrest in infants.
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23
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Methner DNR, Scherer SE, Welch K, Walkiewicz M, Eng CM, Belmont JW, Powell MC, Korchina V, Doddapaneni HV, Muzny DM, Gibbs RA, Wolf DA, Sanchez LA, Kahn R. Postmortem genetic screening for the identification, verification, and reporting of genetic variants contributing to the sudden death of the young. Genome Res 2016; 26:1170-7. [PMID: 27435932 PMCID: PMC5052040 DOI: 10.1101/gr.195800.115] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 07/15/2016] [Indexed: 12/30/2022]
Abstract
Each year in the United States, thousands of cases of sudden and unexpected deaths of infants, children, and young adults are assigned an undetermined cause of death after postmortem investigation and autopsy. Heritable genetic variants have been suggested as the cause of up to a third of sudden death (SD) cases. Elucidation of the genetic variants involved in SD cases is important to not only help establish cause and manner of death of these individuals, but to also aid in determining whether familial genetic testing should be considered. Previously, these types of postmortem screenings have not been a feasible option for most county medical examiners' and coroners' offices. We sequenced full exons of 64 genes associated with SD in the largest known cohort (351) of infant and young SD decedents using massively parallel sequencing at <$600 per sample. Genetic variants were assessed through literature review and clinical evaluation by a multidisciplinary consortium of experts. Thirteen individuals (3.7%), eight infants (2.8% of those <1 yr of age) and five children/young adults (7.0% of those >1 yr of age), were found to have a reportable genetic variant contributing to SD. These percentages represent an estimate lower than those previously reported. Overall yields and results likely vary between studies due to differences in evaluation techniques and reporting. Additionally, we recommend ongoing assessment of data, including nonreported novel variants, as technology and literature continually advance. This study demonstrates a strategy to implement molecular autopsies in medicolegal investigations of young SD decedents.
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Affiliation(s)
| | - Steven E Scherer
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Katherine Welch
- Harris County Institute of Forensic Sciences, Houston, Texas 77054, USA
| | - Magdalena Walkiewicz
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Christine M Eng
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - John W Belmont
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA; Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Mark C Powell
- Harris County Institute of Forensic Sciences, Houston, Texas 77054, USA
| | - Viktoriya Korchina
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas 77030, USA
| | | | - Donna M Muzny
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Richard A Gibbs
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Dwayne A Wolf
- Harris County Institute of Forensic Sciences, Houston, Texas 77054, USA
| | - Luis A Sanchez
- Harris County Institute of Forensic Sciences, Houston, Texas 77054, USA
| | - Roger Kahn
- Harris County Institute of Forensic Sciences, Houston, Texas 77054, USA
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24
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Nunes ML. Intrauterine exposition to smoking and autonomic nervous system function during sleep. Clin Neurophysiol 2016; 127:2869-2870. [PMID: 27316316 DOI: 10.1016/j.clinph.2016.05.360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 05/26/2016] [Indexed: 11/16/2022]
Affiliation(s)
- Magda Lahorgue Nunes
- Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), School of Medicine and the Brain Institute (InsCer), Researcher 1D from CNPq-Brazil, Porto Alegre, 90610000, Av. Ipiranga 6690, Building 63, Room 103, Brazil.
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25
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Jeevaratnam K, Guzadhur L, Goh YM, Grace AA, Huang CLH. Sodium channel haploinsufficiency and structural change in ventricular arrhythmogenesis. Acta Physiol (Oxf) 2016; 216:186-202. [PMID: 26284956 DOI: 10.1111/apha.12577] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Revised: 06/11/2015] [Accepted: 07/24/2015] [Indexed: 12/19/2022]
Abstract
Normal cardiac excitation involves orderly conduction of electrical activation and recovery dependent upon surface membrane, voltage-gated, sodium (Na(+) ) channel α-subunits (Nav 1.5). We summarize experimental studies of physiological and clinical consequences of loss-of-function Na(+) channel mutations. Of these conditions, Brugada syndrome (BrS) and progressive cardiac conduction defect (PCCD) are associated with sudden, often fatal, ventricular tachycardia (VT) or fibrillation. Mouse Scn5a(+/-) hearts replicate important clinical phenotypes modelling these human conditions. The arrhythmic phenotype is associated not only with the primary biophysical change but also with additional, anatomical abnormalities, in turn dependent upon age and sex, each themselves exerting arrhythmic effects. Available evidence suggests a unified binary scheme for the development of arrhythmia in both BrS and PCCD. Previous biophysical studies suggested that Nav 1.5 deficiency produces a background electrophysiological defect compromising conduction, thereby producing an arrhythmic substrate unmasked by flecainide or ajmaline challenge. More recent reports further suggest a progressive decline in conduction velocity and increase in its dispersion particularly in ageing male Nav 1.5 haploinsufficient compared to WT hearts. This appears to involve a selective appearance of slow conduction at the expense of rapidly conducting pathways with changes in their frequency distributions. These changes were related to increased cardiac fibrosis. It is thus the combination of the structural and biophysical changes both accentuating arrhythmic substrate that may produce arrhythmic tendency. This binary scheme explains the combined requirement for separate, biophysical and structural changes, particularly occurring in ageing Nav 1.5 haploinsufficient males in producing clinical arrhythmia.
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Affiliation(s)
- K. Jeevaratnam
- Faculty of Health and Medical Science; University of Surrey; Guilford UK
- Perdana University - Royal College of Surgeons Ireland; Serdang Selangor Darul Ehsan Malaysia
| | - L. Guzadhur
- Division of Cardiovascular Biology; Department of Biochemistry; University of Cambridge; Cambridge UK
- Niche Science & Technology; Richmond UK
| | - Y. M. Goh
- Department of Preclinical Sciences; Faculty of Veterinary Medicine; University Putra Malaysia; Serdang Selangor Darul Ehsan Malaysia
| | - A. A. Grace
- Division of Cardiovascular Biology; Department of Biochemistry; University of Cambridge; Cambridge UK
| | - C. L.-H. Huang
- Division of Cardiovascular Biology; Department of Biochemistry; University of Cambridge; Cambridge UK
- Physiological Laboratory; University of Cambridge; Cambridge UK
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26
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Frolov RV, Weckström M. Harnessing the Flow of Excitation: TRP, Voltage-Gated Na(+), and Voltage-Gated Ca(2+) Channels in Contemporary Medicine. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2015; 103:25-95. [PMID: 26920687 DOI: 10.1016/bs.apcsb.2015.11.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cellular signaling in both excitable and nonexcitable cells involves several classes of ion channels. Some of them are of minor importance, with very specialized roles in physiology, but here we concentrate on three major channel classes: TRP (transient receptor potential channels), voltage-gated sodium channels (Nav), and voltage-gated calcium channels (Cav). Here, we first propose a conceptual framework binding together all three classes of ion channels, a "flow-of-excitation model" that takes into account the inputs mediated by TRP and other similar channels, the outputs invariably provided by Cav channels, and the regenerative transmission of signals in the neural networks, for which Nav channels are responsible. We use this framework to examine the function, structure, and pharmacology of these channel classes both at cellular and also at whole-body physiological level. Building on that basis we go through the pathologies arising from the direct or indirect malfunction of the channels, utilizing ion channel defects, the channelopathies. The pharmacological interventions affecting these channels are numerous. Part of those are well-established treatments, like treatment of hypertension or some forms of epilepsy, but many other are deeply problematic due to poor drug specificity, ion channel diversity, and widespread expression of the channels in tissues other than those actually targeted.
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Affiliation(s)
- Roman V Frolov
- Division of Biophysics, Department of Physics, University of Oulu, Oulun Yliopisto, Finland.
| | - Matti Weckström
- Division of Biophysics, Department of Physics, University of Oulu, Oulun Yliopisto, Finland
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Abstract
Voltage-gated sodium channels (VGSCs) are responsible for the initiation and propagation of action potentials in excitable cells. VGSCs in mammalian brain are heterotrimeric complexes of α and β subunits. Although β subunits were originally termed auxiliary, we now know that they are multifunctional signaling molecules that play roles in both excitable and nonexcitable cell types and with or without the pore-forming α subunit present. β subunits function in VGSC and potassium channel modulation, cell adhesion, and gene regulation, with particularly important roles in brain development. Mutations in the genes encoding β subunits are linked to a number of diseases, including epilepsy, sudden death syndromes like SUDEP and SIDS, and cardiac arrhythmia. Although VGSC β subunit-specific drugs have not yet been developed, this protein family is an emerging therapeutic target.
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Affiliation(s)
- Heather A O'Malley
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan 48109;
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Farrugia A, Keyser C, Hollard C, Raul J, Muller J, Ludes B. Targeted next generation sequencing application in cardiac channelopathies: Analysis of a cohort of autopsy-negative sudden unexplained deaths. Forensic Sci Int 2015; 254:5-11. [DOI: 10.1016/j.forsciint.2015.06.023] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2015] [Revised: 05/22/2015] [Accepted: 06/24/2015] [Indexed: 12/19/2022]
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29
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Marcsa B, Dénes R, Vörös K, Rácz G, Sasvári-Székely M, Rónai Z, Törő K, Keszler G. A Common Polymorphism of the Human Cardiac Sodium Channel Alpha Subunit (SCN5A) Gene Is Associated with Sudden Cardiac Death in Chronic Ischemic Heart Disease. PLoS One 2015; 10:e0132137. [PMID: 26146998 PMCID: PMC4492622 DOI: 10.1371/journal.pone.0132137] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 06/10/2015] [Indexed: 11/18/2022] Open
Abstract
Cardiac death remains one of the leading causes of mortality worldwide. Recent research has shed light on pathophysiological mechanisms underlying cardiac death, and several genetic variants in novel candidate genes have been identified as risk factors. However, the vast majority of studies performed so far investigated genetic associations with specific forms of cardiac death only (sudden, arrhythmogenic, ischemic etc.). The aim of the present investigation was to find a genetic marker that can be used as a general, powerful predictor of cardiac death risk. To this end, a case-control association study was performed on a heterogeneous cohort of cardiac death victims (n=360) and age-matched controls (n=300). Five single nucleotide polymorphisms (SNPs) from five candidate genes (beta2 adrenergic receptor, nitric oxide synthase 1 adaptor protein, ryanodine receptor 2, sodium channel type V alpha subunit and transforming growth factor-beta receptor 2) that had previously been shown to associate with certain forms of cardiac death were genotyped using sequence-specific real-time PCR probes. Logistic regression analysis revealed that the CC genotype of the rs11720524 polymorphism in the SCN5A gene encoding a subunit of the cardiac voltage-gated sodium channel occurred more frequently in the highly heterogeneous cardiac death cohort compared to the control population (p=0.019, odds ratio: 1.351). A detailed subgroup analysis uncovered that this effect was due to an association of this variant with cardiac death in chronic ischemic heart disease (p=0.012, odds ratio = 1.455). None of the other investigated polymorphisms showed association with cardiac death in this context. In conclusion, our results shed light on the role of this non-coding polymorphism in cardiac death in ischemic cardiomyopathy. Functional studies are needed to explore the pathophysiological background of this association.
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Affiliation(s)
- Boglárka Marcsa
- Department of Medical Chemistry, Molecular Biology and Pathobiochemistry, Semmelweis University, Budapest, Hungary
| | - Réka Dénes
- Department of Medical Chemistry, Molecular Biology and Pathobiochemistry, Semmelweis University, Budapest, Hungary
| | - Krisztina Vörös
- Department of Medical Chemistry, Molecular Biology and Pathobiochemistry, Semmelweis University, Budapest, Hungary
| | - Gergely Rácz
- 1st Department of Pathology and Experimental Cancer Research, Semmelweis University, Budapest, Hungary
| | - Mária Sasvári-Székely
- Department of Medical Chemistry, Molecular Biology and Pathobiochemistry, Semmelweis University, Budapest, Hungary
| | - Zsolt Rónai
- Department of Medical Chemistry, Molecular Biology and Pathobiochemistry, Semmelweis University, Budapest, Hungary
| | - Klára Törő
- Department of Forensic and Insurance Medicine, Semmelweis University, Budapest, Hungary
| | - Gergely Keszler
- Department of Medical Chemistry, Molecular Biology and Pathobiochemistry, Semmelweis University, Budapest, Hungary
- * E-mail:
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30
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Wong LCH, Behr ER. Author's reply: To PMID 24585884. Europace 2015; 17:1739-40. [PMID: 26056186 DOI: 10.1093/europace/euv094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Leonie C H Wong
- Cardiovascular and Cell Sciences Research Institute, St George's University of London, Cranmer Terrace, London SW17 0RE, UK
| | - Elijah R Behr
- Cardiovascular and Cell Sciences Research Institute, St George's University of London, Cranmer Terrace, London SW17 0RE, UK
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31
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Wilders R. A note on the prevalence of cardiac ion channelopathies in the sudden infant death syndrome. Europace 2015; 17:1739. [PMID: 26056187 DOI: 10.1093/europace/euv081] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Ronald Wilders
- Department of Anatomy, Embryology and Physiology, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ Amsterdam, The Netherlands
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32
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The role of the sodium current complex in a nonreferred nationwide cohort of sudden infant death syndrome. Heart Rhythm 2015; 12:1241-9. [DOI: 10.1016/j.hrthm.2015.03.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Indexed: 11/18/2022]
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A novel truncation mutation in GJA1 associated with open angle glaucoma and microcornea in a large Chinese family. Eye (Lond) 2015; 29:972-7. [PMID: 25976645 DOI: 10.1038/eye.2015.74] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Accepted: 03/17/2015] [Indexed: 11/08/2022] Open
Abstract
PURPOSE To identify genetic defects in a large family with open angle glaucoma (OAG) and microcornea. METHODS Genomic DNA was prepared from leukocytes of 15 individuals from three generations of a Chinese family, including seven individuals with OAG and microcornea, one with microcornea alone, and seven healthy individuals. Whole exome sequencing was performed on genomic DNA of the proband. Candidate variants were obtained through multiple steps of bioinformatics analysis and validated by Sanger sequencing and segregation analysis. RESULTS Exome sequencing detected a candidate variant in GJA1, a novel truncation mutation (c.791_792delAA, p.K264Ifs*43). This mutation was present in all seven individuals with OAG and microcornea and the individual with microcornea alone, but not in the seven unaffected relatives in the family. It was not present in 1394 alleles from 505 unrelated controls without glaucoma and 192 normal controls. Extraocular signs were not observed in seven out of the eight individuals; only one was affected with dental enamel hypoplasia and syndactyly. CONCLUSIONS A novel truncation mutation in GJA1 is associated with OAG and microcornea in a Chinese family. This suggests that GJA1 should be included as a candidate gene for glaucoma.
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Friedrich C, Rinné S, Zumhagen S, Kiper AK, Silbernagel N, Netter MF, Stallmeyer B, Schulze-Bahr E, Decher N. Gain-of-function mutation in TASK-4 channels and severe cardiac conduction disorder. EMBO Mol Med 2015; 6:937-51. [PMID: 24972929 PMCID: PMC4119356 DOI: 10.15252/emmm.201303783] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Analyzing a patient with progressive and severe cardiac conduction disorder combined with idiopathic ventricular fibrillation (IVF), we identified a splice site mutation in the sodium channel gene SCN5A. Due to the severe phenotype, we performed whole-exome sequencing (WES) and identified an additional mutation in the KCNK17 gene encoding the K2P potassium channel TASK-4. The heterozygous change (c.262G>A) resulted in the p.Gly88Arg mutation in the first extracellular pore loop. Mutant TASK-4 channels generated threefold increased currents, while surface expression was unchanged, indicating enhanced conductivity. When co-expressed with wild-type channels, the gain-of-function by G88R was conferred in a dominant-active manner. We demonstrate that KCNK17 is strongly expressed in human Purkinje cells and that overexpression of G88R leads to a hyperpolarization and strong slowing of the upstroke velocity of spontaneously beating HL-1 cells. Thus, we propose that a gain-of-function by TASK-4 in the conduction system might aggravate slowed conductivity by the loss of sodium channel function. Moreover, WES supports a second hit-hypothesis in severe arrhythmia cases and identified KCNK17 as a novel arrhythmia gene.
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Affiliation(s)
- Corinna Friedrich
- Department of Cardiovascular Medicine, Institute for Genetics of Heart Diseases (IfGH), University Hospital Münster, Münster, Germany
| | - Susanne Rinné
- Institute of Physiology and Pathophysiology, Vegetative Physiology, University of Marburg, Marburg, Germany
| | - Sven Zumhagen
- Department of Cardiovascular Medicine, Institute for Genetics of Heart Diseases (IfGH), University Hospital Münster, Münster, Germany
| | - Aytug K Kiper
- Institute of Physiology and Pathophysiology, Vegetative Physiology, University of Marburg, Marburg, Germany
| | - Nicole Silbernagel
- Institute of Physiology and Pathophysiology, Vegetative Physiology, University of Marburg, Marburg, Germany
| | - Michael F Netter
- Institute of Physiology and Pathophysiology, Vegetative Physiology, University of Marburg, Marburg, Germany
| | - Birgit Stallmeyer
- Department of Cardiovascular Medicine, Institute for Genetics of Heart Diseases (IfGH), University Hospital Münster, Münster, Germany
| | - Eric Schulze-Bahr
- Department of Cardiovascular Medicine, Institute for Genetics of Heart Diseases (IfGH), University Hospital Münster, Münster, Germany
| | - Niels Decher
- Institute of Physiology and Pathophysiology, Vegetative Physiology, University of Marburg, Marburg, Germany
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36
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Sweeting J, Semsarian C. Cardiac abnormalities and sudden infant death syndrome. Paediatr Respir Rev 2014; 15:301-6. [PMID: 25301030 DOI: 10.1016/j.prrv.2014.09.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Accepted: 09/15/2014] [Indexed: 12/01/2022]
Abstract
Many factors have been implicated in SIDS cases including environmental influences such as sleeping arrangements and smoking. Most recently, cardiac abnormalities have been hypothesised to play a role in some cases, particularly the primary genetic arrhythmogenic disorders such as familial long QT syndrome (LQTS). Both post-mortem and clinical studies of SIDS cases have provided supporting evidence for the involvement of cardiac genetic disorders in SIDS. This review provides a summary of this evidence focussing particularly on the primary hypothesis related to underlying familial LQTS. In addition, the current literature relating to other cardiac genetic conditions such as Brugada syndrome (BrS) and structural heart diseases such as hypertrophic cardiomyopathy (HCM) is briefly presented. Finally, the implications of a possible cardiac genetic cause of SIDS is discussed with reference to the need for genetic testing in SIDS cases and subsequent clinical and genetic testing in family members.
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Affiliation(s)
- Joanna Sweeting
- Agnes Ginges Centre for Molecular Cardiology, Centenary Institute, Newtown, Australia
| | - Christopher Semsarian
- Agnes Ginges Centre for Molecular Cardiology, Centenary Institute, Newtown, Australia; Sydney Medical School, University of Sydney, Sydney, Australia; Department of Cardiology, Royal Prince Alfred Hospital, Sydney, NSW, Australia.
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37
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Verkerk AO, Wilders R. Pacemaker activity of the human sinoatrial node: effects of HCN4 mutations on the hyperpolarization-activated current. Europace 2014; 16:384-95. [PMID: 24569893 DOI: 10.1093/europace/eut348] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The hyperpolarization-activated 'funny' current, If, plays an important modulating role in the pacemaker activity of the human sinoatrial node (SAN). If is carried by hyperpolarization-activated cyclic nucleotide-gated (HCN) channels, which are tetramers built of four HCN subunits. In human SAN, HCN4 is the most abundant of the four isoforms of the HCN family. Since 2003, several loss-of-function mutations in the HCN4 gene, which encodes the HCN4 protein, or in the KCNE2 gene, which encodes the MiRP1 accessory β-subunit, have been associated with sinus node dysfunction. Voltage-clamp experiments on HCN4 channels expressed in COS-7 cells, Xenopus oocytes, or HEK-293 cells have revealed changes in the expression and kinetics of mutant channels, but the extent to which these changes would affect If flowing during a human SAN action potential is unresolved. Here, we review the changes in expression and kinetics of HCN4 mutant channels and provide an overview of their effects on If during the time course of a human SAN action potential, both under resting conditions and upon adrenergic stimulation. These effects are assessed in simulated action potential clamp experiments, with action potentials recorded from isolated human SAN pacemaker cells as command potential and kinetics of If based on voltage-clamp data from these cells. Results from in vitro and in silico experiments show several inconsistencies with clinical observations, pointing to challenges for future research.
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Affiliation(s)
- Arie O Verkerk
- Department of Anatomy, Embryology and Physiology, Academic Medical Center, University of Amsterdam, PO Box 22700, 1100 DE Amsterdam, The Netherlands
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38
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Glengarry JM, Crawford J, Morrow PL, Stables SR, Love DR, Skinner JR. Long QT molecular autopsy in sudden infant death syndrome. Arch Dis Child 2014; 99:635-40. [PMID: 24596401 PMCID: PMC4078670 DOI: 10.1136/archdischild-2013-305331] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Revised: 12/29/2013] [Accepted: 02/10/2014] [Indexed: 11/08/2022]
Abstract
OBJECTIVE To describe experience of long QT (LQT) molecular autopsy in sudden infant death syndrome (SIDS). DESIGN Descriptive audit from two distinct periods: (1) A prospective, population-based series between 2006 and 2008 ('unselected'). (2) Before and after 2006-2008, with testing guided by a cardiac genetic service ('selected'). LQT genes 1, 2, 3, 5, 6 and 7 were sequenced. Next of kin were offered cardiac evaluation. SETTING New Zealand. PATIENTS 102 SIDS cases. INTERVENTIONS Nil. Main outcome measures Detection of genetic variants. RESULTS Maori 49 (47%), and Pacific island 24 (23%), infants were over-represented. Risk factors were common; bed sharing was reported in 49%. Rare genetic variants were commoner within the selected than unselected populations (5 of 31 infants (16%) vs 3 of 71 infants (4%) p < 0.05). In the selected population two infants had variants of definite or probable pathogenicity (KCNQ1, E146K; KCNH2, R1047L), two had novel variants of possible pathogenicity in SCN5A (I795F, F1522Y) and one had R1193Q in SCN5A, of doubtful pathogenicity. R1193Q was also the only variant in the three cases from the unselected population and occurred as a second variant with R1047L. Engaging families proved challenging. Only 3 of 8 (38%) variant-positive cases and 18 of 94 (19%) of variant-negative families participated in cardiac/genetic screening. CONCLUSIONS LQT molecular autopsy has a very low diagnostic yield among unselected SIDS cases where risk factors are common. Diagnostic yield can be higher with case selection. Engagement of the family prior to genetic testing is essential to counsel for the possible uncertainty of the results and to permit family genotype-phenotype cosegregation studies.
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Affiliation(s)
- Thomas J Hund
- From The Ohio State University Wexner Medical Center, Columbus
| | - Peter J Mohler
- From The Ohio State University Wexner Medical Center, Columbus.
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40
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Elias MD, Iyer VR, Cohen MS. Prevalence of electrocardiogram use in infants with apparent life-threatening events: a multicenter database study. Pediatr Emerg Care 2014; 30:236-9. [PMID: 24651217 DOI: 10.1097/pec.0000000000000103] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE An apparent life-threatening event (ALTE) is a common diagnosis in pediatrics, but there is no standardized method to evaluate these patients. We sought to determine the prevalence of electrocardiogram (ECG) use in patients presenting to children's hospitals with an ALTE. METHODS The data from the Pediatric Health Information System database from 43 children's hospitals were collected during a 15-month period between October 2009 and December 2010. Patients were included if they were younger than 1 year at the time of presentation. Demographic data, including age, length of hospital stay, second ALTE, and survival, were recorded, along with the prevalence of ECGs and International Classification of Diseases, Ninth Revision, cardiac diagnoses. RESULTS There were 2179 patients with an ALTE, with a mean age of 65.7 days old and length of stay of 3.4 days. A total of 947 (43%) of these patients received an ECG. The prevalence of ECG use and cardiac diagnoses were variable among the participating hospitals. Depending on the institution, 0% to 93% of patients had an ECG, and 4% to 39% of patients had an International Classification of Diseases, Ninth Revision, cardiac diagnosis. CONCLUSIONS Electrocardiograms are performed in fewer than half of patients with ALTE presenting to children's hospitals. There is wide variation in the prevalence of ECG use as a diagnostic tool for infants presenting with an ALTE.
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Affiliation(s)
- Matthew D Elias
- From the Divisions of *General Pediatrics and †Cardiology, The Children's Hospital of Philadelphia, Philadelphia, PA
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41
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Campuzano O, Allegue C, Partemi S, Iglesias A, Oliva A, Brugada R. Negative autopsy and sudden cardiac death. Int J Legal Med 2014; 128:599-606. [PMID: 24532175 DOI: 10.1007/s00414-014-0966-4] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Accepted: 01/15/2014] [Indexed: 12/20/2022]
Abstract
Forensic medicine defines the unexplained sudden death as a death with a non-conclusive diagnosis after autopsy. Molecular diagnosis is being progressively incorporated in forensics, mainly due to improvement in genetics. New genetic technologies may help to identify the genetic cause of death, despite clinical interpretation of genetic data remains the current challenge. The identification of an inheritable defect responsible for arrhythmogenic syndromes could help to adopt preventive measures in family members, many of them asymptomatic but at risk of sudden death. This multidisciplinary translational research requires a specialized team.
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Affiliation(s)
- Oscar Campuzano
- Cardiovascular Genetic Center, University of Girona-IDIBGI, Girona, Spain
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42
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Miller D, Wang L, Zhong J. Sodium channels, cardiac arrhythmia, and therapeutic strategy. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2014; 70:367-92. [PMID: 24931202 DOI: 10.1016/b978-0-12-417197-8.00012-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Cardiac sodium channels are transmembrane proteins distributed in atrial and ventricular myocytes and Purkinje fibers. A large and rapid Na(+) influx through these channels initiates action potential and thus excitation-contraction coupling of cardiac cells. Cardiac sodium channel is composed of a pore-forming α-subunit and one or two accessory β-subunits. The cardiac α-subunit is encoded by gene SCN5A located on chromosome 3p21. There are four types of β-subunits identified so far, and β1 is the primary β-subunit in cardiac Na(+) channels. The gene responsible for β1 subunits is SCNB. The expression of β-subunits together with α subunits enhances the Na(+) current and modifies the channel activities. In addition, interactions of the cardiac Na(+) channel with other proteins may facilitate the channel activity and membrane expression of the channel. Over the past two decades, molecular genetic studies have identified the linkage of gene mutations of the Na(+) channel proteins and other regulatory proteins to many inherited arrhythmogenic diseases. The most common cardiac arrhythmogenic diseases associated with Na(+) channelopathies are long QT syndrome (LQT3) and Brugada syndromes (BrSs). This chapter intends to summarize the current understanding of the normal sodium-channel structure and function, the gene mutation-associated cardiac arrhythmias, and the current diagnosis and management of these diseases.
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Affiliation(s)
- Dori Miller
- Department of Anatomy, Physiology & Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA
| | - Lili Wang
- Department of Anatomy, Physiology & Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA
| | - Juming Zhong
- Department of Anatomy, Physiology & Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA.
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Inherited arrhythmia syndromes leading to sudden cardiac death in the young: a global update and an Indian perspective. Indian Heart J 2013; 66 Suppl 1:S49-57. [PMID: 24568830 DOI: 10.1016/j.ihj.2013.11.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Accepted: 11/07/2013] [Indexed: 12/15/2022] Open
Abstract
Inherited primary arrhythmias, namely congenital long QT syndrome, Brugada syndrome and catecholaminergic polymorphic ventricular tachycardia, account for a significant proportion of sudden cardiac deaths in young and apparently healthy individuals. Genetic testing plays an integral role in the diagnosis, risk-stratification and treatment of probands and family members. It is increasingly obvious that collaborative efforts are required to understand and manage these relatively rare but potentially lethal diseases. This article aims to update readers on the recent developments in our knowledge of inherited arrhythmias and to lay the foundation for a national synergistic effort to characterize them in the Indian population.
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KATO KOICHI, MAKIYAMA TAKERU, WU JIE, DING WEIGUANG, KIMURA HIROMI, NAIKI NOBU, OHNO SEIKO, ITOH HIDEKI, NAKANISHI TOSHIO, MATSUURA HIROSHI, HORIE MINORU. Cardiac Channelopathies Associated with Infantile Fatal Ventricular Arrhythmias: From the Cradle to the Bench. J Cardiovasc Electrophysiol 2013; 25:66-73. [DOI: 10.1111/jce.12270] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 07/16/2013] [Accepted: 08/12/2013] [Indexed: 11/29/2022]
Affiliation(s)
- KOICHI KATO
- Department of Cardiovascular and Respiratory Medicine; Shiga University of Medical Science; Shiga Japan
| | - TAKERU MAKIYAMA
- Department of Cardiovascular Medicine; Kyoto University Graduate School of Medicine; Kyoto Japan
| | - JIE WU
- Department of Cardiovascular and Respiratory Medicine; Shiga University of Medical Science; Shiga Japan
- Department of Pharmacology; Medical School of Xi'an Jiaotong University; Xi'an China
| | - WEI-GUANG DING
- Department of Physiology; Shiga University of Medical Science; Shiga Japan
| | - HIROMI KIMURA
- Department of Cardiovascular and Respiratory Medicine; Shiga University of Medical Science; Shiga Japan
| | - NOBU NAIKI
- Department of Cardiovascular and Respiratory Medicine; Shiga University of Medical Science; Shiga Japan
| | - SEIKO OHNO
- Department of Cardiovascular and Respiratory Medicine; Shiga University of Medical Science; Shiga Japan
| | - HIDEKI ITOH
- Department of Cardiovascular and Respiratory Medicine; Shiga University of Medical Science; Shiga Japan
| | - TOSHIO NAKANISHI
- Department of Pediatric Cardiology; Tokyo Women's Medical University; Tokyo Japan
| | - HIROSHI MATSUURA
- Department of Physiology; Shiga University of Medical Science; Shiga Japan
| | - MINORU HORIE
- Department of Cardiovascular and Respiratory Medicine; Shiga University of Medical Science; Shiga Japan
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Cordeiro JM, Panama BK, Goodrow R, Zygmunt AC, White C, Treat JA, Zeina T, Nesterenko VV, Di Diego JM, Burashnikov A, Antzelevitch C. Developmental changes in expression and biophysics of ion channels in the canine ventricle. J Mol Cell Cardiol 2013; 64:79-89. [PMID: 24035801 DOI: 10.1016/j.yjmcc.2013.09.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 08/12/2013] [Accepted: 09/02/2013] [Indexed: 11/17/2022]
Abstract
BACKGROUND Developmental changes in the electrical characteristics of the ventricular myocardium are not well defined. This study examines the contribution of inwardly rectifying K(+) current (IK1), transient outward K(+) current (Ito), delayed rectifier K(+) currents (IKr and IKs) and sodium channel current (INa) to repolarization in the canine neonate myocardium. METHODS Single myocytes isolated from the left ventricle of 2-3week old canine neonate hearts were studied using patch-clamp techniques. RESULTS Neonate cells were ~6-fold smaller than those of adults (28.8±8.8 vs. 176±6.7pF). IK1 was larger in neonate myocytes and displayed a substantial inward component and an outward component with negative slope conductance, peaking at -60mV (4.13 pA/pF). IKr tail currents (at -40mV), were small (<20pA). IKs could not be detected, even after exposure to isoproterenol (100nM). Ito was also absent in the neonate, consistent with the absence of a phase 1 in the action potential. Peak INa, late INa and ICa were smaller in the neonate compared with adults. KCND3, KCNIP2 and KCNQ1 mRNA expression was half, while KCNH2 was equal and KCNJ2 was greater in the neonate when compared with adults. CONCLUSIONS Two major repolarizing K(+) currents (IKs and Ito) present in adult ventricular cells are absent in the 2week old neonate. Peak and late INa are significantly smaller in the neonate. Our results suggest that the absence of these two currents in the neonate heart may increase the susceptibility to arrhythmias under certain long QT conditions.
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Affiliation(s)
- Jonathan M Cordeiro
- Department of Experimental Cardiology, Masonic Medical Research Laboratory, 2150 Bleecker St., Utica, NY 13501, USA.
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Brugada J, Blom N, Sarquella-Brugada G, Blomstrom-Lundqvist C, Deanfield J, Janousek J, Abrams D, Bauersfeld U, Brugada R, Drago F, de Groot N, Happonen JM, Hebe J, Yen Ho S, Marijon E, Paul T, Pfammatter JP, Rosenthal E. Pharmacological and non-pharmacological therapy for arrhythmias in the pediatric population: EHRA and AEPC-Arrhythmia Working Group joint consensus statement. ACTA ACUST UNITED AC 2013; 15:1337-82. [DOI: 10.1093/europace/eut082] [Citation(s) in RCA: 217] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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Array comparative genomic hybridization as a clinical diagnostic tool in syndromic and nonsyndromic congenital heart disease. Pediatr Res 2013; 73:772-6. [PMID: 23481551 DOI: 10.1038/pr.2013.41] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
BACKGROUND Congenital heart diseases (CHDs) are often associated with other congenital anomalies, dysmorphic features, and developmental delay, and only a few cases of chromosomal abnormalities are detected by conventional cytogenetic techniques. The microarray comparative genomic hybridization (CGH) analysis allows the identification of submicroscopic genomic rearrangements. METHODS During the past 3 y, 55 of 330 patients referred for array CGH had CHD of unknown etiology plus at least one additional indication of abnormal chromosomal phenotype. High-resolution 1 × 244 K or 4 × 180 K Agilent arrays were used in this study (average resolution 7-13 kb). RESULTS Copy-number variations were detected in 37 of 55 patients, and in 29 of 37 patients there were genes that have been associated with CHD. All 37 patients had at least one additional phenotypic abnormality: 30 of 37 had one or more other congenital anomalies, 23 of 37 had dysmorphic features, 16 of 37 had intellectual disability, 13 of 37 had abnormal magnetic resonance imaging, 10 of 37 had hypotonia, and 7 of 37 had seizures. In 9 of 55 patients, unexpected genomic rearrangements in relation to their phenotype were identified. CONCLUSION In patients with CHD and at least one additional indication of abnormal chromosomal phenotype, array CGH analysis could detect possible submicroscopic chromosomal abnormalities and provide proper genetic counseling.
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Martin CA, Huang CLH, Matthews GDK. The role of ion channelopathies in sudden cardiac death: implications for clinical practice. Ann Med 2013; 45:364-74. [PMID: 23651009 DOI: 10.3109/07853890.2013.783994] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Sudden cardiac death (SCD) following ventricular tachyarrhythmias constitutes an important clinical cause of mortality; 4% of cases may involve ion channel-mediated cellular excitation in structurally normal hearts. Alterations in such processes could disturb action potential conduction, depolarization/ repolarization gradients, or Ca(2+) homeostasis with potential arrhythmogenic consequences. Although SCD may be the first presentation of arrhythmic syndromes, patients may present to the general physician with symptoms of palpitations or hemodynamic compromise, including dizziness, seizure, or syncope, particularly following exertion. In all inherited cardiac death syndromes, first-degree relatives should be referred to a cardiologist and should undergo testing appropriate for the condition. While management of patients at risk of SCD largely centers on risk stratification and, if necessary, insertion of an implantable cardioverter-defibrillator, there are a number of other, pharmacological, treatments being developed. Furthermore, as the genetic basis of these diseases becomes established, genetic testing will form an increasingly important part of diagnosis, and gene-specific therapy is an area under investigation. This article bridges the gap between molecular medicine and clinical practice by reviewing recent developments in the pathophysiological understanding of SCD, and their implications for the management of patients with these complex diseases.
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Affiliation(s)
- Claire A Martin
- Physiological Laboratory, University of Cambridge, Downing Site, Cambridge CB2 3EG, UK.
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