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Ukachukwu CU, Jimenez-Vazquez EN, Jain A, Jones DK. hERG1 channel subunit composition mediates proton inhibition of rapid delayed rectifier potassium current (I Kr) in cardiomyocytes derived from hiPSCs. J Biol Chem 2023; 299:102778. [PMID: 36496073 PMCID: PMC9867984 DOI: 10.1016/j.jbc.2022.102778] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 11/29/2022] [Accepted: 12/04/2022] [Indexed: 12/13/2022] Open
Abstract
The voltage-gated channel, hERG1, conducts the rapid delayed rectifier potassium current (IKr) and is critical for human cardiac repolarization. Reduced IKr causes long QT syndrome and increases the risk for cardiac arrhythmia and sudden death. At least two subunits form functional hERG1 channels, hERG1a and hERG1b. Changes in hERG1a/1b abundance modulate IKr kinetics, magnitude, and drug sensitivity. Studies from native cardiac tissue suggest that hERG1 subunit abundance is dynamically regulated, but the impact of altered subunit abundance on IKr and its response to external stressors is not well understood. Here, we used a substrate-driven human-induced pluripotent stem cell-derived cardiomyocyte (hiPSC-CM) maturation model to investigate how changes in relative hERG1a/1b subunit abundance impact the response of native IKr to extracellular acidosis, a known component of ischemic heart disease and sudden infant death syndrome. IKr recorded from immatured hiPSC-CMs displays a 2-fold greater inhibition by extracellular acidosis (pH 6.3) compared with matured hiPSC-CMs. Quantitative RT-PCR and immunocytochemistry demonstrated that hERG1a subunit mRNA and protein were upregulated and hERG1b subunit mRNA and protein were downregulated in matured hiPSC-CMs compared with immatured hiPSC-CMs. The shift in subunit abundance in matured hiPSC-CMs was accompanied by increased IKr. Silencing hERG1b's impact on native IKr kinetics by overexpressing a polypeptide identical to the hERG1a N-terminal Per-Arnt-Sim domain reduced the magnitude of IKr proton inhibition in immatured hiPSC-CMs to levels comparable to those observed in matured hiPSC-CMs. These data demonstrate that hERG1 subunit abundance is dynamically regulated and determines IKr proton sensitivity in hiPSC-CMs.
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Affiliation(s)
- Chiamaka U Ukachukwu
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Eric N Jimenez-Vazquez
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Abhilasha Jain
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - David K Jones
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan, USA; Department of Internal Medicine, University of Michigan Medical School.
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2
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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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Davis AM, Glengarry J, Skinner JR. Sudden Infant Death: QT or Not QT? That Is No Longer the Question. Circ Arrhythm Electrophysiol 2018; 9:CIRCEP.115.003859. [PMID: 27217342 DOI: 10.1161/circep.115.003859] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 03/11/2016] [Indexed: 02/07/2023]
Affiliation(s)
- Andrew M Davis
- From the Department of Cardiology, Royal Children's Hospital Melbourne, Melbourne, VIC, Australia (A.M.D.); Department of Paediatrics, University of Melbourne, Melbourne, VIC, Australia (A.M.D.); The Murdoch Childrens Research Institute, Melbourne, VIC, Australia (A.M.D.); Department of Forensic Pathology, LabPlus, Auckland City Hospital, Auckland, New Zealand (J.G.); Green Lane Paediatric and Congenital Cardiac Services, Starship Children's Hospital, Auckland, New Zealand (J.R.S.); and Department of Paediatrics, Child and Youth Health, The University of Auckland, Auckland, New Zealand (J.R.S.)
| | - Joanna Glengarry
- From the Department of Cardiology, Royal Children's Hospital Melbourne, Melbourne, VIC, Australia (A.M.D.); Department of Paediatrics, University of Melbourne, Melbourne, VIC, Australia (A.M.D.); The Murdoch Childrens Research Institute, Melbourne, VIC, Australia (A.M.D.); Department of Forensic Pathology, LabPlus, Auckland City Hospital, Auckland, New Zealand (J.G.); Green Lane Paediatric and Congenital Cardiac Services, Starship Children's Hospital, Auckland, New Zealand (J.R.S.); and Department of Paediatrics, Child and Youth Health, The University of Auckland, Auckland, New Zealand (J.R.S.)
| | - Jonathan R Skinner
- From the Department of Cardiology, Royal Children's Hospital Melbourne, Melbourne, VIC, Australia (A.M.D.); Department of Paediatrics, University of Melbourne, Melbourne, VIC, Australia (A.M.D.); The Murdoch Childrens Research Institute, Melbourne, VIC, Australia (A.M.D.); Department of Forensic Pathology, LabPlus, Auckland City Hospital, Auckland, New Zealand (J.G.); Green Lane Paediatric and Congenital Cardiac Services, Starship Children's Hospital, Auckland, New Zealand (J.R.S.); and Department of Paediatrics, Child and Youth Health, The University of Auckland, Auckland, New Zealand (J.R.S.).
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4
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Wang J, Wang X, Ma Z, Yun K, Liu J, Chen D, Liu Z, Shi J, Li Z, Gao C, Du Q, Zhang G. A SNaPshot assay for detection of 45 mutations in the SCN5A gene in the Chinese Han Population. Electrophoresis 2018; 39:2270-2276. [DOI: 10.1002/elps.201800096] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2018] [Revised: 05/25/2018] [Accepted: 05/30/2018] [Indexed: 11/07/2022]
Affiliation(s)
- Jiaqi Wang
- School of Forensic Medicine; Shanxi Medical University; Taiyuan P. R. China
| | - Xudong Wang
- Forensic Science Engineering Research Center of Universities in Chongqing; Chongqing P. R. China
| | - Zhihua Ma
- Key Laboratory of Criminal Science and Technology of Chongqing City; Chongqing P. R. China
| | - Keming Yun
- School of Forensic Medicine; Shanxi Medical University; Taiyuan P. R. China
| | - Jinding Liu
- School of Forensic Medicine; Shanxi Medical University; Taiyuan P. R. China
| | - Deqing Chen
- School of Forensic Medicine; Shanxi Medical University; Taiyuan P. R. China
| | - Zidong Liu
- School of Forensic Medicine; Shanxi Medical University; Taiyuan P. R. China
| | - Jie Shi
- School of Forensic Medicine; Shanxi Medical University; Taiyuan P. R. China
| | - Zeqin Li
- School of Forensic Medicine; Shanxi Medical University; Taiyuan P. R. China
| | - Cairong Gao
- School of Forensic Medicine; Shanxi Medical University; Taiyuan P. R. China
| | - Qiuxiang Du
- School of Forensic Medicine; Shanxi Medical University; Taiyuan P. R. China
| | - Gengqian Zhang
- School of Forensic Medicine; Shanxi Medical University; Taiyuan P. R. China
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5
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Baruteau AE, Tester DJ, Kapplinger JD, Ackerman MJ, Behr ER. Sudden infant death syndrome and inherited cardiac conditions. Nat Rev Cardiol 2017; 14:715-726. [PMID: 28880023 DOI: 10.1038/nrcardio.2017.129] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Sudden infant death syndrome (SIDS) is the leading cause of post-neonatal infant mortality in developed countries, characterized by the death of infants for no obvious reason and without prior warning. The complex interaction of multiple factors in the pathogenesis of SIDS is illustrated by the 'triple risk hypothesis', which proposed that SIDS results from a convergence of three overlapping risk factors: a critical developmental period, an exogenous stressor, and underlying genetic and/or nongenetic vulnerability in the infant. Rare variants in genes associated with inherited arrhythmia syndromes and cardiomyopathies have been proposed as the substrate for an infant's critical vulnerability in a small subset of SIDS cases. Given the potential risk of inherited cardiac disease, current guidelines recommend post-mortem genetic testing (molecular autopsy) and cardiological investigation of the surviving family, complemented by targeted genetic testing if appropriate. In this Review, we highlight the latest developments in understanding the spectrum and prevalence of cardiac-mediated SIDS, and discuss the clinical implications of SIDS in the surviving family and the general population.
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Affiliation(s)
- Alban-Elouen Baruteau
- Cardiology Clinical Academic Group, Molecular and Clinical Sciences Research Institute, St George's University of London, Cranmer Terrace, London SW17 0RE, UK.,Department of Congenital Cardiology, Evelina London Children's Hospital, Guy's and St Thomas' NHS Foundation Trust, Westminster Bridge Road, London SE1 7EH, UK
| | - David J Tester
- Department of Molecular Pharmacology & Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, 200 First Street SW, Rochester, Minnesota 55905, USA.,Department of Cardiovascular Diseases, Division of Heart Rhythm Services, and Department of Pediatrics, Division of Pediatric Cardiology, Mayo Clinic, 200 First Street SW, Rochester, Minnesota 55905, USA
| | - Jamie D Kapplinger
- Department of Molecular Pharmacology & Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, 200 First Street SW, Rochester, Minnesota 55905, USA
| | - Michael J Ackerman
- Department of Molecular Pharmacology & Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, 200 First Street SW, Rochester, Minnesota 55905, USA.,Department of Cardiovascular Diseases, Division of Heart Rhythm Services, and Department of Pediatrics, Division of Pediatric Cardiology, Mayo Clinic, 200 First Street SW, Rochester, Minnesota 55905, USA
| | - Elijah R Behr
- Cardiology Clinical Academic Group, Molecular and Clinical Sciences Research Institute, St George's University of London, Cranmer Terrace, London SW17 0RE, UK
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Van Niekerk C, Van Deventer BS, du Toit-Prinsloo L. Long QT syndrome and sudden unexpected infant death. J Clin Pathol 2017; 70:808-813. [PMID: 28663329 DOI: 10.1136/jclinpath-2016-204199] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 06/01/2017] [Accepted: 06/05/2017] [Indexed: 12/30/2022]
Abstract
Long QT syndrome (LQTS) is an inheritable primary electric disease of the heart characterised by abnormally long QT intervals and a propensity to develop atrial and ventricular tachyarrhythmias. It is caused by an inherited channelopathy responsible for sudden cardiac death in individuals with structurally normal hearts. Long QT syndrome can present early in life, and some studies suggest that it may be associated with up to 20% of sudden unexplained infant death (SUID), particularly when associated with external stressors such as asphyxia, which is commonly seen in many infant death scenes. With an understanding of the genetic defects, it has now been possible to retrospectively analyse samples from infants who have presented to forensic pathology services with a history of unexplained sudden death, which may, in turn, enable the implementation of preventative treatment for siblings previously not known to have pathogenic genetic variations. In this viewpoint article, we will discuss SUID, LQTS and postmortem genetic analysis.
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Affiliation(s)
- Chantal Van Niekerk
- Department of Chemical Pathology, National Health Laboratory Service, Johannesburg, Gauteng, South Africa.,Department of Chemical Pathology, University of Pretoria, Pretoria, South Africa
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Poetsch M, Todt R, Vennemann M, Bajanowski T. That's not it, either-neither polymorphisms in PHOX2B nor in MIF are involved in sudden infant death syndrome (SIDS). Int J Legal Med 2015; 129:985-9. [PMID: 26104808 DOI: 10.1007/s00414-015-1213-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 06/03/2015] [Indexed: 11/30/2022]
Abstract
The occurrence of sudden infant death syndrome (SIDS) has been linked to several genetic risk factors, e.g. genes involved in the neuroadrenergic system, variations in serotonin reporter genes or mutations in long-QT syndrome genes. Additionally, polymorphisms in genes with impact in sleep disorder syndromes have been proposed to be of importance as genetic risk factors for SIDS. In this study, we investigated the polyalanine length variation of PHOX2B and the -794 CATT repeat in the MIF promoter region as well as single nucleotide polymorphisms (rs28462174, rs28727473, rs16853571, rs755622, rs12485058, rs12485068, rs4822444, rs4822445, rs4822446, rs4822447 and rs2012124) in both genes in 278 SIDS cases and 240 controls. No significant differences were found in allele distribution of neither length polymorphisms nor single nucleotide polymorphisms between SIDS cases or controls. Therefore, an importance of these variations for the occurrence of SIDS could be ruled out.
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Affiliation(s)
- Micaela Poetsch
- Institute of Legal Medicine, University Hospital Essen, Hufelandstraße 55, 45122, Essen, Germany,
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8
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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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9
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Forensische Molekularpathologie. Rechtsmedizin (Berl) 2014. [DOI: 10.1007/s00194-014-0975-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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10
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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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11
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Deeg KH, Reisig A. [Sonographic screening of basilar arteries reduces the risk of sudden infant death]. Radiologe 2013; 53:791-9. [PMID: 23807597 DOI: 10.1007/s00117-012-2443-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Sudden infant death syndrome (SIDS) is the most frequent cause of death in the first year of life. The causes of SIDS remain unclear although multiple theories have been published in recent decades. However, some important risk factors associated with SIDS, such as prone sleeping have been validated. Over 85% of all SIDS victims were found in a prone position but it is unclear why the prone sleeping position is more dangerous than the supine sleeping position. A possible cause of SIDS is hypoperfusion of the brain stem during head rotation. Some infants show compression of the vertebral arteries at the craniocervical junction during head rotation, especially in the prone position and this may lead to a subsequent decrease of brain stem perfusion. If compression lasts for a longer time hypoperfusion of the brainstem and central apnea and bradycardia result, which can lead to SIDS. The decrease in brainstem perfusion occurs more often and is more pronounced in the prone position as the head is more rotated in the prone than in the supine position. Doppler sonographic flow measurements of the flow in the basilar artery through the open fontanel, allow the detection of patients at risk of position-dependent hypoperfusion of the brain. Flow measurements are obtained in a neutral position (head in midline) and during head rotation. In the vast majority of infants (98.7%) the flow in the basilar artery is independent of head rotation and body position. In rare cases (1.3%) flow velocities drop to below 50% of the initial value during head rotation. A pathological biphasic or even retrograde flow can be found during head rotation in only 0.3% of infants and these infants may have an increased risk for SIDS. To prevent SIDS head rotation which leads to an abnormal or pathological flow decrease during head rotation should be avoided. Additionally these infants should be monitored until blood flow in the basilar artery has returned to normal, which usually occurs during the first year of life. This approach reduced the incidence of SIDS in our patients from 1% to 0.04‰.
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Affiliation(s)
- K H Deeg
- Klink für Kinder und Jugendliche, Sozialstiftung Bamberg, Bugerstr. 80, 96049, Bamberg, Deutschland,
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12
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Huang P, Yu R, Li S, Qin Z, Liu N, Zhang J, Zou D, Chen Y. Sudden twin infant death on the same day: a case report and review of the literature. Forensic Sci Med Pathol 2013; 9:225-30. [PMID: 23526355 DOI: 10.1007/s12024-013-9429-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/07/2013] [Indexed: 11/30/2022]
Abstract
Sudden infant death syndrome (SIDS) is a major contributor to infant mortality. The cause of death is unknown: suggested possibilities include cardiovascular disease, anaphylactic shock, and suffocation. The occurrence of simultaneous sudden infant death syndrome is uncommon, such cases being extremely rare in forensic pathologic practice. We report two 10-week-old male twins who appeared well at the time of their evening feeding, yet died while sleeping on their backs. Both infants had petechial hemorrhages on the visceral pleura, epicardial surface of the heart, and thymus gland. Microscopic examination revealed pulmonary edema, intra-alveolar hemorrhage, and minor lymphocytic infiltration, again in both infants. In this report, we discuss the risk factors for SIDS, which should be considered individually or in combination as possible causes of death.
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Affiliation(s)
- Ping Huang
- Department of Forensic Pathology, Institute of Forensic Science, Ministry of Justice, 1347 West Guangfu Road, Shanghai, 200063, People's Republic of China
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13
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Wilders R. Cardiac ion channelopathies and the sudden infant death syndrome. ISRN CARDIOLOGY 2012; 2012:846171. [PMID: 23304551 PMCID: PMC3529486 DOI: 10.5402/2012/846171] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 10/23/2012] [Indexed: 12/13/2022]
Abstract
The sudden infant death syndrome (SIDS) causes the sudden death of an apparently healthy infant, which remains unexplained despite a thorough investigation, including the performance of a complete autopsy. The triple risk model for the pathogenesis of SIDS points to the coincidence of a vulnerable infant, a critical developmental period, and an exogenous stressor. Primary electrical diseases of the heart, which may cause lethal arrhythmias as a result of dysfunctioning cardiac ion channels (“cardiac ion channelopathies”) and are not detectable during a standard postmortem examination, may create the vulnerable infant and thus contribute to SIDS. Evidence comes from clinical correlations between the long QT syndrome and SIDS as well as genetic analyses in cohorts of SIDS victims (“molecular autopsy”), which have revealed a large number of mutations in ion channel-related genes linked to inheritable arrhythmogenic syndromes, in particular the long QT syndrome, the short QT syndrome, the Brugada syndrome, and catecholaminergic polymorphic ventricular tachycardia. Combining data from population-based cohort studies, it can be concluded that at least one out of five SIDS victims carries a mutation in a cardiac ion channel-related gene and that the majority of these mutations are of a known malignant phenotype.
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Affiliation(s)
- Ronald Wilders
- Department of Anatomy, Embryology and Physiology, Heart Failure Research Center, Academic Medical Center, University of Amsterdam, P.O. Box 22700, 1100 DE Amsterdam, The Netherlands
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14
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Cardiac ion channel mutations in the sudden infant death syndrome. Int J Cardiol 2011; 152:162-70. [DOI: 10.1016/j.ijcard.2010.12.051] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Revised: 11/27/2010] [Accepted: 12/08/2010] [Indexed: 12/19/2022]
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Tfelt-Hansen J, Winkel BG, Grunnet M, Jespersen T. Cardiac channelopathies and sudden infant death syndrome. Cardiology 2011; 119:21-33. [PMID: 21778721 DOI: 10.1159/000329047] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Accepted: 04/24/2011] [Indexed: 12/19/2022]
Abstract
Sudden infant death syndrome (SIDS) is always a devastating and unexpected occurrence. SIDS is the leading cause of death in the first 6 months after birth in the industrialized world. Since the discovery in 1998 of long QT syndrome as an underlying substrate for SIDS, around 10-20% of SIDS cases have been proposed as being caused by genetic variants in either ion channel or ion channel-associated proteins. Until now, 10 cardiac channelopathy susceptibility genes have been found to be implicated in the pathogenesis of SIDS. Four of the genes encode cardiac ion channel α-subunits, 3 genes encode ion channel β-subunits, and 3 genes encode other channel-interacting proteins. All 10 genes have been associated with primary electrical heart diseases. SIDS may hereby be the initial symptom of rare primary electric channelopathies such as long QT, short QT and Brugada syndrome, as well as catecholaminergic polymorphic ventricular tachycardia. In this review we describe the functional role of sodium, potassium and calcium channels in propagation, depolarization and repolarization in the context of the 4 arrhythmogenic diseases reported to be associated with SIDS. Lastly, the possibility of postmortem genetic testing and potential recommendations on how to deal with family members are discussed.
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Affiliation(s)
- Jacob Tfelt-Hansen
- Danish National Research Foundation Centre for Cardiac Arrhythmia (DARC), Copenhagen, Denmark.
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Stead LF, Wood IC, Westhead DR. KvSNP: accurately predicting the effect of genetic variants in voltage-gated potassium channels. ACTA ACUST UNITED AC 2011; 27:2181-6. [PMID: 21685056 DOI: 10.1093/bioinformatics/btr365] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
MOTIVATION Non-synonymous single nucleotide polymorphisms (nsSNPs) in voltage-gated potassium (Kv) channels cause diseases with potentially fatal consequences in seemingly healthy individuals. Identifying disease-causing genetic variation will aid presymptomatic diagnosis and treatment of such disorders. NsSNP-effect predictors are hypothesized to perform best when developed for specific gene families. We, thus, created KvSNP: a method that assigns a disease-causing probability to Kv-channel nsSNPs. RESULTS KvSNP outperforms popular non gene-family-specific methods (SNPs&GO, SIFT and Polyphen) in predicting the disease potential of Kv-channel variants, according to all tested metrics (accuracy, Matthews correlation coefficient and area under receiver operator characteristic curve). Most significantly, it increases the separation of the median predicted disease probabilities between benign and disease-causing SNPs by 26% on the next-best competitor. KvSNP has ranked 172 uncharacterized Kv-channel nsSNPs by disease-causing probability. AVAILABILITY AND IMPLEMENTATION KvSNP, a WEKA implementation is available at www.bioinformatics.leeds.ac.uk/KvDB/KvSNP.html. CONTACT d.r.westhead@leeds.ac.uk SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- L F Stead
- Institute of Molecular and Cellular Biology, Faculty of Biological Sciences and Institute of Membrane and Systems Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
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Opdal SH, Rognum TO. Gene variants predisposing to SIDS: current knowledge. Forensic Sci Med Pathol 2010; 7:26-36. [PMID: 20623341 DOI: 10.1007/s12024-010-9182-9] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/21/2010] [Indexed: 01/04/2023]
Abstract
Genetic risk factors play a role in sudden unexpected infant death; either as a cause of death, such as in cases with medium-chain acyl-coenzyme A dehydrogenase deficiency and cardiac arrest due to long QT syndrome, or as predisposing factors for sudden infant death syndrome (SIDS). Most likely genetic predisposition to SIDS represent a polygenic inheritance pattern leading to sudden death when combined with other risk factors, such as a vulnerable developmental stage of the central nervous system and/or the immune system, in addition to environmental risk factors, such as a common cold or prone sleeping position. Genes involved in the regulation of the immune system, cardiac function, the serotonergic network and brain function and development have so far emerged as the most important with respect to SIDS. The purpose of the present paper is to survey current knowledge on SIDS and possible genetic contributions.
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Affiliation(s)
- Siri H Opdal
- Institute of Forensic Medicine, University of Oslo, Oslo, Norway.
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18
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Genetic analysis of sudden cardiac death victims: a survey of current forensic autopsy practices. Int J Legal Med 2010; 125:359-66. [DOI: 10.1007/s00414-010-0474-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2010] [Accepted: 05/21/2010] [Indexed: 01/16/2023]
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A common FMO3 polymorphism may amplify the effect of nicotine exposure in sudden infant death syndrome (SIDS). Int J Legal Med 2010; 124:301-6. [PMID: 20198379 DOI: 10.1007/s00414-010-0428-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2009] [Accepted: 01/29/2010] [Indexed: 10/19/2022]
Abstract
Smoking during pregnancy has been identified as one of the major modifiable risk factors of sudden infant death syndrome (SIDS). It has been demonstrated that the risk of SIDS increases with increasing cigarette consumption. A variety of hypotheses have been proposed for explanation, including a genetic predisposition. The flavin-monooxygenase 3 (FMO3) is one of the enzymes metabolising nicotine, and several polymorphisms have already been described in this gene. Here, we studied variations in the exons and introns of the FMO3 gene by direct sequencing analysis and minisequencing in 159 SIDS cases and 170 controls. The three common variants G472A (E158K), G769A (V257M) and A923G (E308G) in the exons of the FMO3 gene were identified. The homozygote 472AA genotype occurred more frequently in SIDS cases than in controls (p = 0.0054) and was more frequent in those SIDS cases for which the mothers reported heavy smoking (p = 0.0084). This study is the first to demonstrate a gene-environment interaction in SIDS. The findings suggest that the common polymorphism G472A of FMO3 could act as an additional genetic SIDS risk factor in children whose mothers smoke. Parents who could pass on the 472A allele should be informed of the increased risk associated with smoking. Smoking mothers should be strongly advised to give up smoking during pregnancy and for at least the first year of the child's life.
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Poetsch M, Nottebaum BJ, Wingenfeld L, Frede S, Vennemann M, Bajanowski T. Impact of sodium/proton exchanger 3 gene variants on sudden infant death syndrome. J Pediatr 2010; 156:44-48.e1. [PMID: 19772970 DOI: 10.1016/j.jpeds.2009.07.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2008] [Revised: 05/21/2009] [Accepted: 07/07/2009] [Indexed: 10/20/2022]
Abstract
OBJECTIVE To determine the contribution of variations in the sodium/proton exchanger 3 (NHE3) gene in sudden infant death syndrome (SIDS). STUDY DESIGN Variations in the exons and promoter of the NHE3 gene were analyzed with direct sequencing analysis and mini sequencing (SNaPshot analysis) in 251 cases of SIDS, plus 50 infant control subjects who had died of other causes, and 170 healthy adults. RESULTS The C2405T variant (exon 16) and 2 polymorphisms in the promoter (G1131A and C1197T) were encountered significantly more frequently in cases of SIDS than in control subjects. At least 1 of these 3 variants was detected in 49% of SIDS cases, but only in 30% of control subjects. CONCLUSIONS Our findings suggest the involvement of polymorphisms in the NHE3 gene and promoter in cases of SIDS, which may result in an overexpression of NHE3 in the medulla oblongata and which possibly leads to a disturbance in breathing control. Furthermore, our results underline the heterogeneous character of SIDS.
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Affiliation(s)
- Micaela Poetsch
- Institute of Forensic Medicine, University Hospital Essen, Essen, Germany.
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Gow RM, Ewald B, Lai L, Gardin L, Lougheed J. The measurement of the QT and QTc on the neonatal and infant electrocardiogram: a comprehensive reliability assessment. Ann Noninvasive Electrocardiol 2009; 14:165-75. [PMID: 19419402 DOI: 10.1111/j.1542-474x.2009.00292.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND An electrocardiogram has been proposed to screen for prolonged QT interval that may predispose infants to sudden death in the first year of life. Understanding the reliability of QT interval measurement will inform the design of a screening program. METHODS Three pediatric cardiologists measured the QT/RR intervals on 60 infant electrocardiograms (median age 46 days), from leads II, V5 and V6 on three separate occasions, 7 days apart, according to a standard protocol. The QTc was corrected by Bazett's (QTcB), Fridericia's (QT(CFrid)), and Hodges' (QTcH) formulae. Intraobserver and interobserver reliability were assessed by intraclass correlation coefficients (ICC), limits of agreement and repeatability coefficients for single, average of two and average of three measures. Agreement for QTc prolongation (> 440 msec) was assessed by kappa coefficients. RESULTS QT interval intraobserver ICC was 0.86 and repeatability coefficient was 25.9 msec; interobserver ICC increased from 0.88 for single observations to 0.94 for the average of 3 measurements and repeatability coefficients decreased from 22.5 to 16.7 msec. For QTcB, intraobserver ICC was 0.67, and repeatability was 39.6 msec. Best interobserver reliability for QTcB was for the average of three measurements (ICC 0.83, reproducibility coefficient 25.8 msec), with further improvement for QTcH (ICC 0.92, reproducibility coefficient 16.69 msec). Maximum interobserver kappa for prolonged QTc was 0.77. Misclassification around specific cut points occurs because of the repeatability coefficients. CONCLUSIONS Uncorrected QT measures are more reliable than QTcB and QT(CFrid). An average of three independent measures provides the most reliable QT and QTc measurements, with QTcH better than QTcB.
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Affiliation(s)
- Robert M Gow
- The Children's Hospital of Eastern Ontario, University of Ottawa Faculty of Medicine, 401 Smyth Road, Ottawa, Ontario, Canada.
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Kaufman ES. Mechanisms and clinical management of inherited channelopathies: Long QT syndrome, Brugada syndrome, catecholaminergic polymorphic ventricular tachycardia, and short QT syndrome. Heart Rhythm 2009; 6:S51-5. [DOI: 10.1016/j.hrthm.2009.02.009] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2008] [Indexed: 10/21/2022]
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Abstract
The cause of sudden infant death syndrome (SIDS) is unknown. Many mechanisms have been postulated, although thermal stress, rebreathing of expired gases and infection/inflammation seem the most viable hypotheses for the causation of SIDS. Deaths from SIDS have reduced dramatically following the recommendation not to place infants to sleep prone. Epidemiological data have shown that prone sleeping position is more risky in winter, colder latitudes, higher altitudes, if the infant is unwell or has excessive bedding or clothing. This suggests prone sleeping position involves either directly or indirectly a thermal mechanism. SIDS caused by an infective/inflammatory mechanism might be associated with deaths occurring during the night. Rebreathing of expired gases, airway obstruction, long QT syndrome and other genetic conditions may explain a small number of sudden unexpected deaths in infancy.
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Affiliation(s)
- Edwin A Mitchell
- Department of Paediatrics, University of Auckland, Private Bag 92019, Auckland, New Zealand.
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Millat G, Kugener B, Chevalier P, Chahine M, Huang H, Malicier D, Rodriguez-Lafrasse C, Rousson R. Contribution of long-QT syndrome genetic variants in sudden infant death syndrome. Pediatr Cardiol 2009; 30:502-9. [PMID: 19322600 DOI: 10.1007/s00246-009-9417-2] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2008] [Revised: 01/21/2009] [Accepted: 03/11/2009] [Indexed: 11/27/2022]
Abstract
A cohort of 52 French unrelated infant cases who died unexpectedly before they reached 12 months of age was blindly investigated to better quantify the contribution of long-QT syndrome (LQTS) genetic variants in French cases of sudden infant death syndrome (SIDS). After a standardized autopsy protocol, a blinded molecular screening of the KCNQ1, KCNH2, SCN5A, KCNE1, and KCNE2 genes was performed on each case. These postmortem investigations enabled us to reclassify 18 as non-SIDS cases, 32 as SIDS cases, and 2 as suspected SIDS cases. Among the 18 non-SIDS cases, no LQTS mutation was identified. In contrast, our results led to a possible explanation for the death of at least three infants in the SIDS cohort. Half of the LQTS gene variants identified were located on the SCN5A gene. This study confirms that LQTS mutations may represent one of the leading genetic causes of SIDS. If autopsy fails to provide an explanation for an unexplained infant death, medicolegal investigation should be extended with a molecular screening of major LQTS genes. Identification of more LQTS mutations in SIDS cases could provide new insights into the pathophysiology of SIDS and, consequently, reduce the number of unexplained sudden infant deaths.
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Affiliation(s)
- Gilles Millat
- Laboratoire de Cardiogénétique Moléculaire, Centre de Biologie et Pathologie Est, Hospices Civils de Lyon, Lyon, Bron Cedex, France.
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Nishio H, Kuwahara M, Tsubone H, Koda Y, Sato T, Fukunishi S, Tamura A, Suzuki K. Identification of an ethnic-specific variant (V207M) of the KCNQ1 cardiac potassium channel gene in sudden unexplained death and implications from a knock-in mouse model. Int J Legal Med 2009; 123:253-7. [DOI: 10.1007/s00414-009-0321-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2008] [Accepted: 01/05/2009] [Indexed: 11/24/2022]
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Sudden death due to pulmonary embolism from right atrial myxoma. Int J Legal Med 2009; 123:157-9. [DOI: 10.1007/s00414-008-0312-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2008] [Accepted: 12/11/2008] [Indexed: 11/25/2022]
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Marfan syndrome: clinical consequences resulting from a medicolegal autopsy of a case of sudden death due to aortic rupture. Int J Legal Med 2008; 123:55-8. [PMID: 18925407 DOI: 10.1007/s00414-008-0288-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2008] [Accepted: 09/08/2008] [Indexed: 12/13/2022]
Abstract
To investigate the sudden death of a 31-year-old man, a medicolegal autopsy was performed. Major findings were a dilated aortic root with a longitudinal rupture of the intima and dissection of aorta and right coronary artery and consequent tamponade of the pericardial sac. Moreover, arachnodactyly and other skeletal deformities in combination with the histological finding of a pseudocystic medionecrosis of the aortic wall were noted. By sequencing of the FBN1 gene, a mutation (1622G>A) leading to the diagnosis of Marfan syndrome was found. Genetic counseling was recommended to the relatives who reported that the father of the deceased had died at the same age from aortic rupture. While fortunately the child of the deceased lacked this mutation, it was found in his younger sister. The results of the autopsy thus enabled early diagnosis and beginning of treatment in the sister and thus a considerable statistical increase in lifespan. With this report, we want to show that medicolegal autopsies can also have medical consequences for relatives. We argue that in all sudden and unexpected deaths in young persons up to 35 years an autopsy should be performed, not only to detect unnatural causes of death but also to identify heritable diseases and thus aid the relatives.
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Van Norstrand DW, Ackerman MJ. Sudden infant death syndrome: do ion channels play a role? Heart Rhythm 2008; 6:272-8. [PMID: 18823823 DOI: 10.1016/j.hrthm.2008.07.028] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2008] [Indexed: 12/19/2022]
Affiliation(s)
- David W Van Norstrand
- Mayo Clinic, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, Minnesota 55905, USA
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Michaud K, Augsburger M, Donzé N, Sabatasso S, Faouzi M, Bollmann M, Mangin P. Evaluation of postmortem measurement of NT-proBNP as a marker for cardiac function. Int J Legal Med 2008; 122:415-20. [PMID: 18553094 DOI: 10.1007/s00414-008-0257-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2007] [Accepted: 05/20/2008] [Indexed: 10/22/2022]
Abstract
Clinical biomarkers of cardiac function could also be monitored postmortem. Among the natriuretic peptides, the aminoterminal portion of pro-brain natriuretic peptide (NT-proBNP) appears to be a more reliable postmortem tool than the BNP, owing to its longer half-life and greater stability. In living persons, NT-proBNP is considered to be a marker of heart failure, and its level rises after cardiac ischemia. The goal of this study was first to evaluate the postmortem stability of NT-proBNP, then to measure the NT-proBNP levels in postmortem cases of heart failure related to coronary ischemia. The goal of this study was also to evaluate the correlations between different specimens collected at autopsy (e.g. blood, serum, vitreous humor and pericardial fluid). The study included 96 cases, which were classified into 4 groups according to the autopsy and histological findings. The NT-proBNP levels were significantly higher in individuals who had suffered from chronic cardiac ischemia, with or without acute coronary events, than in either control cases or those who had suffered from acute thromboembolism or acute rupture of a plaque without chronic cardiac ischemia. The highest levels were registered in individuals who had suffered from acute coronary thromboembolism in association with chronic coronary ischemia. Good correlations in the NT-proBNP levels for the different specimens were observed between samples of femoral blood, serum, and pericardial fluid. Our data indicated that postmortem measurements of NT-proBNP are reliable and compatible with clinical findings.
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Affiliation(s)
- Katarzyna Michaud
- Centre Universitaire romand de Médecine Légale, Centre Hospitalier Universitaire Vaudois, University of Lausanne, Bugnon 21, 1005, Lausanne, Switzerland.
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Rhodes TE, Abraham RL, Welch RC, Vanoye CG, Crotti L, Arnestad M, Insolia R, Pedrazzini M, Ferrandi C, Vege A, Rognum T, Roden DM, Schwartz PJ, George AL. Cardiac potassium channel dysfunction in sudden infant death syndrome. J Mol Cell Cardiol 2007; 44:571-81. [PMID: 18222468 DOI: 10.1016/j.yjmcc.2007.11.015] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2007] [Revised: 11/26/2007] [Accepted: 11/26/2007] [Indexed: 10/22/2022]
Abstract
Life-threatening arrhythmias have been suspected as one cause of the sudden infant death syndrome (SIDS), and this hypothesis is supported by the observation that mutations in arrhythmia susceptibility genes occur in 5-10% of cases. However, the functional consequences of cardiac potassium channel gene mutations associated with SIDS and how these alleles might mechanistically predispose to sudden death are unknown. To address these questions, we studied four missense KCNH2 (encoding HERG) variants, one compound KCNH2 genotype, and a missense KCNQ1 mutation all previously identified in Norwegian SIDS cases. Three of the six variants exhibited functional impairments while three were biophysically similar to wild-type channels (KCNH2 variants V279M, R885C, and S1040G). When co-expressed with WT-HERG, R273Q and K897T/R954C generated currents resembling the rapid component of the cardiac delayed rectifier current (I(Kr)) but with significantly diminished amplitude. Action potential modeling demonstrated that this level of functional impairment was sufficient to evoke increased action potential duration and pause-dependent early afterdepolarizations. By contrast, KCNQ1-I274V causes a gain-of-function in I(Ks) characterized by increased current density, faster activation, and slower deactivation leading to accumulation of instantaneous current upon repeated stimulation. Action potential simulations using a Markov model of heterozygous I274V-I(Ks) incorporated into the Luo-Rudy (LRd) ventricular cell model demonstrated marked rate-dependent shortening of action potential duration predicting a short QT phenotype. Our results indicate that certain potassium channel mutations associated with SIDS confer overt functional defects consistent with either LQTS or SQTS, and further emphasize the role of congenital arrhythmia susceptibility in this syndrome.
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Affiliation(s)
- Troy E Rhodes
- Department of Medicine, Vanderbilt University, Nashville, TN, USA
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Turillazzi E, Karch SB, Neri M, Pomara C, Riezzo I, Fineschi V. Confocal laser scanning microscopy. Using new technology to answer old questions in forensic investigations. Int J Legal Med 2007; 122:173-7. [PMID: 17924128 DOI: 10.1007/s00414-007-0208-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2007] [Accepted: 09/03/2007] [Indexed: 12/12/2022]
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Border WL, Benson DW. Sudden infant death syndrome and long QT syndrome: the zealots versus the naysayers. Heart Rhythm 2006; 4:167-9. [PMID: 17275751 PMCID: PMC1919417 DOI: 10.1016/j.hrthm.2006.12.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2006] [Indexed: 11/17/2022]
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Nishio H, Iwata M, Suzuki K. Postmortem molecular screening for cardiac ryanodine receptor type 2 mutations in sudden unexplained death: R420W mutated case with characteristics of status thymico-lymphatics. Circ J 2006; 70:1402-6. [PMID: 17062961 DOI: 10.1253/circj.70.1402] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Mutations of the cardiac ryanodine receptor type 2 (RyR2) gene are known to cause effort-induced polymorphic ventricular arrhythmia, syncope and sudden death. METHODS AND RESULTS The possible mutations in the RyR2 gene were examined in 18 autopsy cases of sudden unexplained death (SUD). Two cases were found to have the heterozygous missense mutation in exon 14 (nucleotide change C1258T, coding effect R420W). Both cases showed mild fatty infiltration of the right ventricular apex. Interestingly, 1 case showed an enlarged thymus with accompanying hypertrophy of the tonsils and mesenteric lymph nodes. In addition, a narrowing of the aorta was observed in this case. These phenotypic characteristics are consistent with status thymico-lymphaticus, which combines sudden death with an enlargement of lymphoid organs and hypoplasia of the cardiovascular system. The second case also displayed some characteristics of status thymico-lymphaticus. CONCLUSION The R420W mutation has already been reported in families with juvenile sudden death and may be causative of sudden death in our cases. Postmortem molecular screening of the RyR2 gene could be useful for investigation for cause of death in SUD. The possible association of the RyR2 mutation with status thymico-lymphaticus is discussed.
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Affiliation(s)
- Hajime Nishio
- Department of Legal Medicine, Osaka Medical College, Takatsuki 569-8686, Japan.
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Zhu BL, Ishikawa T, Michiue T, Li DR, Zhao D, Tanaka S, Kamikodai Y, Tsuda K, Okazaki S, Maeda H. Postmortem pericardial natriuretic peptides as markers of cardiac function in medico-legal autopsies. Int J Legal Med 2006; 121:28-35. [PMID: 16741745 DOI: 10.1007/s00414-006-0102-1] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2006] [Accepted: 04/24/2006] [Indexed: 11/29/2022]
Abstract
Atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) in the blood are clinical markers for the diagnosis of cardiac failure. This study was a comprehensive analysis of the postmortem pericardial levels of the natriuretic peptides in serial medico-legal autopsy cases (n=263, within 72 h postmortem) to assess their validity in investigating cardiac function. There was no significant relationship of pericardial ANP or BNP levels with postmortem time or the age of the subjects. The ANP and BNP levels showed negative correlations with the pericardial cardiac troponin T level. The ANP level was significantly elevated in drowning cases. Pericardial BNP and the BNP/ANP ratio were significantly higher for chronic congestive heart disease. However, asphyxiation, sharp instrument injury, hyperthermia, and fatal MA poisoning cases showed lower levels for both markers. These observations suggest that elevations in the postmortem pericardial ANP and BNP may mainly depend on acute atrial overload and subacute or chronic cardiac failure, respectively, and may be reduced by advanced myocardial damage.
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Affiliation(s)
- Bao-Li Zhu
- Department of Legal Medicine, Osaka City University Medical School, Asahi-machi 1-4-3, Abeno, Osaka, 545-8585, Japan.
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Makielski JC. SIDS: genetic and environmental influences may cause arrhythmia in this silent killer. J Clin Invest 2006; 116:297-9. [PMID: 16453014 PMCID: PMC1359061 DOI: 10.1172/jci27689] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
In this issue of the JCI, Bowers et al. show that the common polymorphism of the cardiac voltage-gated sodium channel, type Valpha (SCN5A), designated S1103Y, found in African Americans is associated with an increased risk of sudden infant death syndrome (SIDS). Wild-type and mutant SCN5A channels both functioned typically under normal conditions in vitro, but exposure to acidic intracellular pH levels such as those found in respiratory acidosis--a known risk factor for SIDS--produced abnormal gain-of-function late reopenings of S1103Y channels, behavior that is often associated with cardiac arrhythmias. These pathologic late reopenings were suppressed by low levels of the channel-blocking drug mexiletine. These findings provide an excellent illustration of a causal relationship between the interaction of the environment and genetic background in SIDS and also raise interesting questions about the linkage of a genetic abnormality with a clinical phenotype.
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Affiliation(s)
- Jonathan C Makielski
- Department of Medicine, Cardiovascular Medicine Section and Department of Physiology, University of Wisconsin, Madison, Wisconsin 53792, USA.
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Wedekind H, Schulze-Bahr E, Debus V, Breithardt G, Brinkmann B, Bajanowski T. Cardiac arrhythmias and sudden death in infancy: implication for the medicolegal investigation. Int J Legal Med 2006; 121:245-57. [PMID: 16397808 DOI: 10.1007/s00414-005-0069-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2005] [Accepted: 11/15/2005] [Indexed: 10/25/2022]
Abstract
Genetically transmitted diseases are an important cause of juvenile sudden cardiac death (SCD). In a considerable proportion of individuals in which a medicolegal investigation is performed, structural heart disease is absent, and the medical examiner fails to discover an adequate cause of death. In such cases, an inherited arrhythmogenic disease should be considered, which manifests with life-threatening ventricular tachycardia or SCD. Molecular diagnosis is progressively becoming an important tool for these questions. Therefore, postmortem genetic testing ("molecular autopsy") should be considered as a part of the comprehensive medicolegal investigation in SCD cases without apparent structural heart disease. It will have implications not only for the deceased individual but also for living family members in preventing (further) cardiac events by expert counseling, appropriate lifestyle adjustment, and adequate treatment, if available.
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Affiliation(s)
- Horst Wedekind
- Department of Cardiology and Angiology, University of Münster, Albert-Schweitzer-Strasse 33, 48149 Münster, Germany.
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Schulze-Bahr E. [Primary electrical heart diseases]. Herzschrittmacherther Elektrophysiol 2005; 16:225-8. [PMID: 16362728 DOI: 10.1007/s00399-005-0489-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
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