1
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Clemens DJ, Ye D, Wang L, Kim CSJ, Zhou W, Dotzler SM, Tester DJ, Marty I, Knollmann BC, Ackerman MJ. Cellular and electrophysiological characterization of triadin knockout syndrome using induced pluripotent stem cell-derived cardiomyocytes. Stem Cell Reports 2023; 18:1075-1089. [PMID: 37163978 PMCID: PMC10202692 DOI: 10.1016/j.stemcr.2023.04.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 04/07/2023] [Accepted: 04/11/2023] [Indexed: 05/12/2023] Open
Abstract
Triadin knockout syndrome (TKOS) is a malignant arrhythmia disorder caused by recessive null variants in TRDN-encoded cardiac triadin. Induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) were generated from two unrelated TKOS patients and an unrelated control. CRISPR-Cas9 gene editing was used to insert homozygous TRDN-p.D18fs∗13 into a control line to generate a TKOS model (TRDN-/-). Western blot confirmed total knockout of triadin in patient-specific and TRDN-/- iPSC-CMs. iPSC-CMs from both patients revealed a prolonged action potential duration (APD) at 90% repolarization, and this was normalized by protein replacement of triadin. APD prolongation was confirmed in TRDN-/- iPSC-CMs. TRDN-/- iPSC-CMs revealed that loss of triadin underlies decreased expression and co-localization of key calcium handling proteins, slow and decreased calcium release from the sarcoplasmic reticulum, and slow inactivation of the L-type calcium channel leading to frequent cellular arrhythmias, including early and delayed afterdepolarizations and APD alternans.
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Affiliation(s)
- Daniel J Clemens
- Department of Molecular Pharmacology & Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, MN, USA
| | - Dan Ye
- Department of Molecular Pharmacology & Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, MN, USA; Department of Cardiovascular Medicine, Division of Heart Rhythm Services, Mayo Clinic, Rochester, MN, USA
| | - Lili Wang
- Department of Medicine, Vanderbilt Center for Arrhythmia Research and Therapeutics, Nashville, TN, USA
| | - C S John Kim
- Department of Molecular Pharmacology & Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, MN, USA; Department of Cardiovascular Medicine, Division of Heart Rhythm Services, Mayo Clinic, Rochester, MN, USA
| | - Wei Zhou
- Department of Molecular Pharmacology & Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, MN, USA; Department of Cardiovascular Medicine, Division of Heart Rhythm Services, Mayo Clinic, Rochester, MN, USA
| | - Steven M Dotzler
- Department of Molecular Pharmacology & Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, MN, USA
| | - David J Tester
- Department of Molecular Pharmacology & Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, MN, USA; Department of Cardiovascular Medicine, Division of Heart Rhythm Services, Mayo Clinic, Rochester, MN, USA
| | - Isabelle Marty
- University Grenoble Alpes, INSERM U1216, CHU Grenoble Alpes, Grenoble Institute Neurosciences, 38000 Grenoble, France
| | - Bjorn C Knollmann
- Department of Medicine, Vanderbilt Center for Arrhythmia Research and Therapeutics, Nashville, TN, USA; Vanderbilt School of Medicine, Nashville, TN, USA
| | - Michael J Ackerman
- Department of Molecular Pharmacology & Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, MN, USA; Department of Cardiovascular Medicine, Division of Heart Rhythm Services, Mayo Clinic, Rochester, MN, USA; Department of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology, Mayo Clinic, Rochester, MN, USA.
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2
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Wang M, Tu X. The Genetics and Epigenetics of Ventricular Arrhythmias in Patients Without Structural Heart Disease. Front Cardiovasc Med 2022; 9:891399. [PMID: 35783865 PMCID: PMC9240357 DOI: 10.3389/fcvm.2022.891399] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 05/25/2022] [Indexed: 12/19/2022] Open
Abstract
Ventricular arrhythmia without structural heart disease is an arrhythmic disorder that occurs in structurally normal heart and no transient or reversible arrhythmia factors, such as electrolyte disorders and myocardial ischemia. Ventricular arrhythmias without structural heart disease can be induced by multiple factors, including genetics and environment, which involve different genetic and epigenetic regulation. Familial genetic analysis reveals that cardiac ion-channel disorder and dysfunctional calcium handling are two major causes of this type of heart disease. Genome-wide association studies have identified some genetic susceptibility loci associated with ventricular tachycardia and ventricular fibrillation, yet relatively few loci associated with no structural heart disease. The effects of epigenetics on the ventricular arrhythmias susceptibility genes, involving non-coding RNAs, DNA methylation and other regulatory mechanisms, are gradually being revealed. This article aims to review the knowledge of ventricular arrhythmia without structural heart disease in genetics, and summarizes the current state of epigenetic regulation.
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Sulu A, Karacan M, Ergul Y. A very rare cause of sudden cardiac arrest in children: triadin knockout syndrome. Cardiol Young 2022; 33:1-3. [PMID: 35481495 DOI: 10.1017/s1047951122001226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Triadin knockout syndrome has been defined as a disease with transient long QT, T wave abnormalities, and extremely severe fatal cardiac arrhythmias in young children. In this report, we wanted to share the characteristics of our two cases who presented with sudden cardiac arrest and were diagnosed with triadin knockout syndrome. CASE 1 A 7.5-year-old male patient was referred to our clinic with a history of recurrent syncope and aborted cardiac arrest. There was no family history of sudden death, syncope, or arrhythmia. Physical examination, electrocardiography, echocardiography, and 24-hour rhythm Holter monitoring were normal, and bidirectional ventricular tachycardiaT was detected during the exercise stress test. Genetic analysis revealed a homozygous mutation of c.531_533delinsGG, p.(Lys179Asnfs * 44) frameshift variant in TRDN(NM_006073) gene. CASE 2 A 4.5-year-old male was admitted due to syncope during exertion and underwent cardiopulmonary resuscitation due to sudden cardiac arrest. He had family history about sudden cardiac death. Physical examination was normal, and there was borderline QTc prolongation. Bidirectional non-sustained polymorphic ventricular tachycardia was observed at adrenaline provocation test. In genetic analysis, c.568dupA, pII190Asnfs * 2 frameshift variant homozygous mutation was detected in TRDN(NM_006073) gene. Intracardiac defibrillator implantation were performed for both cases. There has not been any event under propranolol and flecainide combination treatment. CONCLUSION Triadin knockout syndrome (TCOS) is a rare overlap syndrome characterized by highly malignant arrhythmias, and it is a deadly combination of long QT syndrome and catecholaminergic polymorphic ventricular tachycardia that affects primarily young children. Since lethal arrhythmias are frequently described, genetic testing is very important in these patients. Because, identification of a genetic mutation may be a guide in treatment.
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Affiliation(s)
- Ayse Sulu
- Pediatric Cardiology, Istanbul Saglik Bilimleri University Istanbul Mehmet Akif Ersoy Thoracic and Cardiovascular Surgery Education and Research Hospital, Istanbul, Turkey
| | - Mehmet Karacan
- Istanbul Saglik Bilimleri University Istanbul Umraniye Education and Research Hospital, Istanbul, Turkey
| | - Yakup Ergul
- Pediatric Cardiology, Istanbul Saglik Bilimleri University Istanbul Mehmet Akif Ersoy Thoracic and Cardiovascular Surgery Training and Research Hospital, Istanbul, Turkey
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Lin DJ, Lee WS, Chien YC, Chen TY, Yang KT. The link between abnormalities of calcium handling proteins and catecholaminergic polymorphic ventricular tachycardia. Tzu Chi Med J 2021; 33:323-331. [PMID: 34760626 PMCID: PMC8532576 DOI: 10.4103/tcmj.tcmj_288_20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 02/09/2021] [Accepted: 03/03/2021] [Indexed: 01/18/2023] Open
Abstract
Catecholaminergic polymorphic ventricular tachycardia (CPVT), a rare autosomal dominant or recessive disease, usually results in syncope or sudden cardiac death. Most CPVT patients do not show abnormal cardiac structure and electrocardiogram features and symptoms, usually onset during adrenergically mediated physiological conditions. CPVT tends to occur at a younger age and is not easy to be diagnosed and managed. The main cause of CPVT is associated with mishandling Ca2+ in cardiomyocytes. Intracellular Ca2+ is strictly controlled by a protein located in the sarcoplasm reticulum (SR), such as ryanodine receptor, histidine-rich Ca2+-binding protein, triadin, and junctin. Mutation in these proteins results in misfolding or malfunction of these proteins, thereby affecting their Ca2+-binding affinity, and subsequently disturbs Ca2+ homeostasis during excitation–contraction coupling (E-C coupling). Furthermore, transient disturbance of Ca2+ homeostasis increases membrane potential and causes Ca2+ store overload-induced Ca2+ release, which in turn leads to delayed after depolarization and arrhythmia. Previous studies have focused on the interaction between ryanodine receptors and protein kinase or phosphatase in the cytosol. However, recent studies showed the regulation signaling for ryanodine receptor not only from the cytosol but also within the SR. The changing of Ca2+ concentration is critical for protein interaction inside the SR which changes protein conformation to regulate the open probability of ryanodine receptors. Thus, it influences the threshold of Ca2+ released from the SR, making it easier to release Ca2+ during E-C coupling. In this review, we briefly discuss how Ca2+ handling protein variations affect the Ca2+ handling in CPVT.
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Affiliation(s)
- Ding-Jyun Lin
- School of Medicine, Tzu Chi University, Hualien, Taiwan
| | - Wen-Sen Lee
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | | | - Tsung-Yu Chen
- School of Medicine, Tzu Chi University, Hualien, Taiwan
| | - Kun-Ta Yang
- Master Program in Medical Physiology, School of Medicine, Tzu Chi University, Hualien, Taiwan.,Department of Physiology, School of Medicine, Tzu Chi University, Hualien, Taiwan
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5
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Generation of a Triadin KnockOut Syndrome Zebrafish Model. Int J Mol Sci 2021; 22:ijms22189720. [PMID: 34575879 PMCID: PMC8471218 DOI: 10.3390/ijms22189720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Revised: 08/31/2021] [Accepted: 09/03/2021] [Indexed: 11/17/2022] Open
Abstract
Different forms of sudden cardiac death have been described, including a recently identified form of genetic arrhythmogenic disorder, named “Triadin KnockOut Syndrome” (TKOS). TKOS is associated with recessive mutations in the TRDN gene, encoding for TRIADIN, but the pathogenic mechanism underlying the malignant phenotype has yet to be completely defined. Moreover, patients with TKOS are often refractory to conventional treatment, substantiating the need to identify new therapeutic strategies in order to prevent or treat cardiac events. The zebrafish (Danio rerio) heart is highly comparable to the human heart in terms of functions, signal pathways and ion channels, representing a good model to study cardiac disorders. In this work, we generated the first zebrafish model for trdn loss-of-function, by means of trdn morpholino injections, and characterized its phenotype. Although we did not observe any gross cardiac morphological defect between trdn loss-of-function embryos and controls, we found altered cardiac rhythm that was recovered by the administration of arrhythmic drugs. Our model will provide a suitable platform to study the effect of TRDN mutations and to perform drug screening to identify new pharmacological strategies for patients carrying TRDN mutations.
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Rabbani B, Khorgami M, Dalili M, Zamani N, Mahdieh N, Gollob MH. Novel cases of pediatric sudden cardiac death secondary to TRDN mutations presenting as long QT syndrome at rest and catecholaminergic polymorphic ventricular tachycardia during exercise: The TRDN arrhythmia syndrome. Am J Med Genet A 2021; 185:3433-3445. [PMID: 34415104 DOI: 10.1002/ajmg.a.62464] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 07/15/2021] [Accepted: 07/22/2021] [Indexed: 12/15/2022]
Abstract
TRDN mutations cause catecholaminergic polymorphic ventricular tachycardia (CPVT) but may present with abnormal electrocardiogram (ECG) findings provoking a diagnosis of long QT syndrome (LQTS). We report two novel cases of sudden cardiac death in children due to mutations of TRDN, providing further insight into this rare and aggressive inherited arrhythmia syndrome. Whole exome sequencing (WES) was performed in two unrelated children who experienced cardiac arrest during exercise and were negative for targeted testing of LQTS. WES identified a novel homozygous splice-site mutation in both patients, denoted c.22+1G>T, absent from gnomAD and suggesting a founder variant in the Iranian population. We now summarize the genetic architecture of all reported TRDN-related patients, including 27 patients from 21 families. The average age-onset was 30 months (range 1-10) for all cases. Adrenergic-mediated cardiac events were common, occurring in 23 of 27 cases (85%). LQTS was diagnosed in 10 cases (37%), CPVT in 10 (37%) cases, and in 7 cases. No phenotypic diagnosis was provided. Five cases (15%) had evidence for associated skeletal myopathy. Four missense TRDN variants (24%) were observed in diseased cases, while the remaining variants reflect putative loss-of-function (LOF) mutations. No disease phenotype was reported in 26 heterozygous carriers. In conclusion, TRDN mutations cause a rare autosomal recessive arrhythmia syndrome presenting with adrenergic-mediated arrhythmic events, but with ECG abnormalities leading to a diagnosis of LQTS in a proportion of cases. Heterozygous carriers are free of disease manifestations.
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Affiliation(s)
- Bahareh Rabbani
- Growth and Development Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammadrafi Khorgami
- Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Mohammad Dalili
- Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Nasrin Zamani
- Growth and Development Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Nejat Mahdieh
- Growth and Development Research Center, Tehran University of Medical Sciences, Tehran, Iran.,Cardiogenetic Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Michael H Gollob
- Inherited Arrhythmia and Cardiomyopathy Program, Arrhythmia Service, Division of Cardiology, Toronto General Hospital, University of Toronto, Toronto, Ontario, Canada.,Department of Physiology, University of Toronto, Toronto, Ontario, Canada
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7
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Phenotype-guided whole genome analysis in a patient with genetically elusive long QT syndrome yields a novel TRDN-encoded triadin pathogenetic substrate for triadin knockout syndrome and reveals a novel primate-specific cardiac TRDN transcript. Heart Rhythm 2020; 17:1017-1024. [PMID: 32402482 DOI: 10.1016/j.hrthm.2020.01.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 01/14/2020] [Indexed: 12/11/2022]
Abstract
BACKGROUND Triadin knockout syndrome (TKOS) is a rare arrhythmia syndrome caused by recessive null variants in TRDN-encoded cardiac triadin 1. TKOS has presented frequently with cardiac arrest in childhood. OBJECTIVE The purpose of this study was to elucidate the underlying genetic mechanism of disease in a genetically elusive patient displaying a characteristic TKOS phenotype. METHODS Genome sequencing and a TRDN gene-specific trio analysis were completed on the patient. RNA and protein isolated from patient-specific human-induced pluripotent stem cell-derived cardiomyocytes were used to determine the effects of the identified variants using reverse transcription polymerase chain reaction (RT-PCR) and Western blot. RESULTS Genome sequencing revealed compound heterozygous putative splice-error variants (maternal c.22+29A>G and paternal c.484+1189G>A). The novel paternally derived c.484+1189G>A variant is located within 24 base pairs of a predicted alternative exon 6 (exon 6a), which resides within the intron between canonical exons 5 and 6. We determined that this previously unrecognized exon 6a produces a short TRDN transcript and potentially a novel protein isoform in the normal human heart. The c.484+1189G>A variant not only results in abnormal splicing of the exon 6a-containing transcript leading to a frameshift mutation but also results in the abolishment of the 8-exon cardiac triadin 1 transcript. CONCLUSION Here, we present evidence for a novel alternative exon 6a-containing TRDN transcript in the normal heart. The novel deep intronic TRDN variant identified in a patient with TKOS leads to splicing error of a newly recognized exon 6a and loss of triadin. Considering that both TRDN variants in this patient were missed after commercial testing, these results highlight the importance of using genome sequencing when identifying patients with TKOS.
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Clemens DJ, Tester DJ, Giudicessi JR, Bos JM, Rohatgi RK, Abrams DJ, Balaji S, Crotti L, Faure J, Napolitano C, Priori SG, Probst V, Rooryck-Thambo C, Roux-Buisson N, Sacher F, Schwartz PJ, Silka MJ, Walsh MA, Ackerman MJ. International Triadin Knockout Syndrome Registry. CIRCULATION-GENOMIC AND PRECISION MEDICINE 2020; 12:e002419. [PMID: 30649896 DOI: 10.1161/circgen.118.002419] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND Triadin knockout syndrome (TKOS) is a rare, inherited arrhythmia syndrome caused by recessive null mutations in TRDN-encoded cardiac triadin. Based previously on 5 triadin null patients, TKOS has been characterized by extensive T-wave inversions, transient QT prolongation, and severe disease expression of exercise-induced cardiac arrest in early childhood refractory to conventional therapy. METHODS We have established the International Triadin Knockout Syndrome Registry to include patients who have genetically proven homozygous/compound heterozygous TRDN null mutations. Clinical/genetic data were collected using an online survey generated through REDCap. RESULTS Currently, the International Triadin Knockout Syndrome Registry includes 21 patients (11 males, average age of 18 years) from 16 families. Twenty patients (95%) presented with either cardiac arrest (15, 71%) or syncope (5, 24%) at an average age of 3 years. Mild skeletal myopathy/proximal muscle weakness was noted in 6 (29%) patients. Of the 19 surviving patients, 16 (84%) exhibit T-wave inversions, and 10 (53%) have transient QT prolongation > 480 ms. Eight of 9 patients had ventricular ectopy on exercise stress testing. Thirteen (68%) patients have received implantable defibrillators. Despite various treatment strategies, 14 (74%) patients have had recurrent breakthrough cardiac events. CONCLUSION TKOS is a potentially lethal disease characterized by T-wave inversions in the precordial leads, transient QT prolongation in some, and recurrent ventricular arrhythmias at a young age despite aggressive treatment. Patients displaying this phenotype should undergo TRDN genetic testing as TKOS may be a cause for otherwise unexplained cardiac arrest in young children. As gene therapy advances, enrollment into the International Triadin Knockout Syndrome Registry is encouraged to better understand TKOS and to ready a well-characterized cohort for future TRDN gene therapy trials.
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Affiliation(s)
- Daniel J Clemens
- Windland Smith Rice Sudden Death Genomics Laboratory, Department of Molecular Pharmacology and Experimental Therapeutics, Division of Pediatric Cardiology, Department of Pediatric and Adolescent Medicine, and Division of Heart Rhythm Services, Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN (D.J.C., D.J.T., J.R.G., J.M.B., R.K.R., M.J.A.)
| | - David J Tester
- Department of Cardiology, Boston Children's Hospital and Harvard Medical School, MA (D.J.A.)
| | - John R Giudicessi
- Windland Smith Rice Sudden Death Genomics Laboratory, Department of Molecular Pharmacology and Experimental Therapeutics, Division of Pediatric Cardiology, Department of Pediatric and Adolescent Medicine, and Division of Heart Rhythm Services, Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN (D.J.C., D.J.T., J.R.G., J.M.B., R.K.R., M.J.A.)
| | - J Martijn Bos
- Windland Smith Rice Sudden Death Genomics Laboratory, Department of Molecular Pharmacology and Experimental Therapeutics, Division of Pediatric Cardiology, Department of Pediatric and Adolescent Medicine, and Division of Heart Rhythm Services, Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN (D.J.C., D.J.T., J.R.G., J.M.B., R.K.R., M.J.A.)
| | - Ram K Rohatgi
- Windland Smith Rice Sudden Death Genomics Laboratory, Department of Molecular Pharmacology and Experimental Therapeutics, Division of Pediatric Cardiology, Department of Pediatric and Adolescent Medicine, and Division of Heart Rhythm Services, Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN (D.J.C., D.J.T., J.R.G., J.M.B., R.K.R., M.J.A.)
| | - Dominic J Abrams
- Department of Cardiology, Boston Children's Hospital and Harvard Medical School, MA (D.J.A.)
| | - Seshadri Balaji
- Doernbecher Children's Hospital, Oregon Health and Science University, Portland (S.B.)
| | - Lia Crotti
- Center for Cardiac Arrhythmias of Genetic Origin & Laboratory of Cardiovascular Genetics, Istituto Auxologico Italiano, IRCCS, Milan (L.C., P.J.S.).,IRCCS Department of Cardiovascular, Neural & Metabolic Sciences, San Luca Hospital, Istituto Auxologico Italiano (L.C.).,Department of Medicine and Surgery University of Milano-Bicocca, Italy (L.C.)
| | - Julien Faure
- Centre Hospitalier Universitaire de Grenoble Alpes (J.F., N.R.-B.).,Institut des Neurosciences de Grenoble, INSERM U1216, Grenoble, France (J.F., N.R.-B.)
| | - Carlo Napolitano
- Molecular Cardiology and Medicine Division, Istituti Clinici Scientifici Maugeri, IRCCS (C.N., S.G.P.).,Department of Molecular Medicine, University of Pavia, Italy (C.N., S.G.P.)
| | - Silvia G Priori
- Molecular Cardiology and Medicine Division, Istituti Clinici Scientifici Maugeri, IRCCS (C.N., S.G.P.).,Department of Molecular Medicine, University of Pavia, Italy (C.N., S.G.P.)
| | - Vincent Probst
- Reference Center for Rare Arrhythmic Disorders, Cardiologic Department, Nantes University Hospital, France (V.P.).,L'institut du thorax, INSERM 1087, Nantes, France (V.P.)
| | - Caroline Rooryck-Thambo
- Electrophysiology and Heart Modeling Institute, Bordeaux University Hospital, IHU Liryc, University of Bordeaux, Pessac-Bordeaux, France (C.R.-T., F.S.)
| | - Nathalie Roux-Buisson
- Centre Hospitalier Universitaire de Grenoble Alpes (J.F., N.R.-B.).,Institut des Neurosciences de Grenoble, INSERM U1216, Grenoble, France (J.F., N.R.-B.)
| | - Frederic Sacher
- Electrophysiology and Heart Modeling Institute, Bordeaux University Hospital, IHU Liryc, University of Bordeaux, Pessac-Bordeaux, France (C.R.-T., F.S.)
| | - Peter J Schwartz
- Center for Cardiac Arrhythmias of Genetic Origin & Laboratory of Cardiovascular Genetics, Istituto Auxologico Italiano, IRCCS, Milan (L.C., P.J.S.)
| | - Michael J Silka
- Children's Hospital Los Angeles, University of Southern California (M.J.S.)
| | - Mark A Walsh
- Paediatric Cardiology, University Hospital Bristol, United Kingdom (M.A.W.)
| | - Michael J Ackerman
- Windland Smith Rice Sudden Death Genomics Laboratory, Department of Molecular Pharmacology and Experimental Therapeutics, Division of Pediatric Cardiology, Department of Pediatric and Adolescent Medicine, and Division of Heart Rhythm Services, Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN (D.J.C., D.J.T., J.R.G., J.M.B., R.K.R., M.J.A.)
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Clemens DJ, Gray B, Bagnall RD, Tester DJ, Dotzler SM, Giudicessi JR, Matthews E, Semsarian C, Behr ER, Ackerman MJ. Triadin Knockout Syndrome Is Absent in a Multi-Center Molecular Autopsy Cohort of Sudden Infant Death Syndrome and Sudden Unexplained Death in the Young and Is Extremely Rare in the General Population. CIRCULATION-GENOMIC AND PRECISION MEDICINE 2020; 13:e002731. [PMID: 32167373 DOI: 10.1161/circgen.119.002731] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
BACKGROUND Triadin knockout syndrome (TKOS) is a potentially lethal arrhythmia disorder caused by recessively inherited null variants in TRDN-encoded cardiac triadin. Despite its malignant phenotype, the prevalence of TKOS in sudden infant death syndrome and sudden unexplained death in the young is unknown. METHODS Exome sequencing was performed on 599 sudden infant death syndrome and 258 sudden unexplained death in the young cases. Allele frequencies of all TRDN null variants identified in the cardiac-specific isoform of TRDN in the Genome Aggregation Database were used to determine the estimated prevalence and ethnic distribution of TKOS. RESULTS No triadin null individuals were identified in 599 sudden infant death syndrome and 258 sudden unexplained death in the young exomes. Using the Genome Aggregation Database, we estimate the overall prevalence of TKOS to be ≈1:22.7 million individuals. However, TKOS prevalence is 5.5-fold higher in those of African descent (≈1:4.1 million). CONCLUSIONS TKOS is an exceedingly rare clinical entity that does not contribute meaningfully to either sudden infant death syndrome or sudden unexplained death in the young. However, despite its rarity and absence in large sudden death cohorts, TKOS remains a malignant and potentially lethal disorder which requires further research to better care for these patients.
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Affiliation(s)
- Daniel J Clemens
- Windland Smith Rice Sudden Death Genomics Laboratory, Department of Molecular Pharmacology and Experimental Therapeutics (D.J.C., D.J.T., S.M.D., M.J.A.), Mayo Clinic, Rochester, MN
| | - Belinda Gray
- Molecular and Clinical Sciences Research Institute, St George's University of London, United Kingdom (B.G., E.R.B.).,Cardiology Clinical Academic Group, St George's University Hospitals' National Health Service (NHS) Foundation Trust, London, United Kingdom (B.G., E.R.B.).,Agnes Ginges Centre for Molecular Cardiology at Centenary Institute (B.G., R.D.B., C.S.), The University of Sydney, Australia.,Sydney Medical School, Faculty of Medicine and Health (B.G., R.D.B., C.S.), The University of Sydney, Australia.,Department of Cardiology, Royal Prince Alfred Hospital, Australia (B.G., C.S.)
| | - Richard D Bagnall
- Agnes Ginges Centre for Molecular Cardiology at Centenary Institute (B.G., R.D.B., C.S.), The University of Sydney, Australia.,Sydney Medical School, Faculty of Medicine and Health (B.G., R.D.B., C.S.), The University of Sydney, Australia
| | - David J Tester
- Windland Smith Rice Sudden Death Genomics Laboratory, Department of Molecular Pharmacology and Experimental Therapeutics (D.J.C., D.J.T., S.M.D., M.J.A.), Mayo Clinic, Rochester, MN.,Division of Heart Rhythm Services, Department of Cardiovascular Medicine (D.J.T., J.R.G., M.J.A.), Mayo Clinic, Rochester, MN
| | - Steven M Dotzler
- Windland Smith Rice Sudden Death Genomics Laboratory, Department of Molecular Pharmacology and Experimental Therapeutics (D.J.C., D.J.T., S.M.D., M.J.A.), Mayo Clinic, Rochester, MN
| | - John R Giudicessi
- Division of Heart Rhythm Services, Department of Cardiovascular Medicine (D.J.T., J.R.G., M.J.A.), Mayo Clinic, Rochester, MN
| | - Emma Matthews
- Medical Research Council Centre for Neuromuscular Diseases, National Hospital for Neurology and Neurosurgery, University College London Institute of Neurology, Queen Square, United Kingdom (E.M.)
| | - Christopher Semsarian
- Agnes Ginges Centre for Molecular Cardiology at Centenary Institute (B.G., R.D.B., C.S.), The University of Sydney, Australia.,Sydney Medical School, Faculty of Medicine and Health (B.G., R.D.B., C.S.), The University of Sydney, Australia.,Department of Cardiology, Royal Prince Alfred Hospital, Australia (B.G., C.S.)
| | - Elijah R Behr
- Molecular and Clinical Sciences Research Institute, St George's University of London, United Kingdom (B.G., E.R.B.).,Cardiology Clinical Academic Group, St George's University Hospitals' National Health Service (NHS) Foundation Trust, London, United Kingdom (B.G., E.R.B.)
| | - Michael J Ackerman
- Windland Smith Rice Sudden Death Genomics Laboratory, Department of Molecular Pharmacology and Experimental Therapeutics (D.J.C., D.J.T., S.M.D., M.J.A.), Mayo Clinic, Rochester, MN.,Division of Heart Rhythm Services, Department of Cardiovascular Medicine (D.J.T., J.R.G., M.J.A.), Mayo Clinic, Rochester, MN.,Division of Pediatric Cardiology, Department of Pediatric and Adolescent Medicine (M.J.A.), Mayo Clinic, Rochester, MN
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10
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Sarquella-Brugada G, Fernandez-Falgueras A, Cesar S, Arbelo E, Jordà P, García-Álvarez A, Cruzalegui JC, Merchan EF, Fiol V, Brugada J, Brugada R, Campuzano O. Pediatric Malignant Arrhythmias Caused by Rare Homozygous Genetic Variants in TRDN: A Comprehensive Interpretation. Front Pediatr 2020; 8:601708. [PMID: 33692971 PMCID: PMC7938306 DOI: 10.3389/fped.2020.601708] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 10/14/2020] [Indexed: 12/19/2022] Open
Abstract
Aim: To perform a comprehensive phenotype-genotype correlation of all rare variants in Triadin leading to malignant arrhythmias in pediatrics. Methods: Triadin knockout syndrome is a rare entity reported in pediatric population. This syndrome is caused by rare variants in the TRDN gene. Malignant ventricular arrhythmias and sudden cardiac death can be a primary manifestation of disease. Although pharmacological measures are effective, some patients require an implantable defibrillator due to high risk of arrhythmogenic episodes. Main Results: Fourteen rare genetic alterations in TRDN have been reported to date. All of these potentially pathogenic alterations are located in a specific area of TRDN, highlighting this hot spot as an arrhythmogenic gene region. Conclusions: Early recognition and comprehensive interpretation of alterations in Triadin are crucial to adopt preventive measures and avoid malignant arrhythmogenic episodes in pediatric population.
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Affiliation(s)
- Georgia Sarquella-Brugada
- Arrhythmias Unit, Hospital Sant Joan de Déu, University of Barcelona, Barcelona, Spain.,Medical Science Department, School of Medicine, University of Girona, Girona, Spain
| | | | - Sergi Cesar
- Arrhythmias Unit, Hospital Sant Joan de Déu, University of Barcelona, Barcelona, Spain
| | - Elena Arbelo
- Arrhythmias Unit, Hospital Clinic, University of Barcelona-IDIBAPS, Barcelona, Spain.,Centro de Investigación Biomédica en Red. Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
| | - Paloma Jordà
- Arrhythmias Unit, Hospital Clinic, University of Barcelona-IDIBAPS, Barcelona, Spain.,Centro de Investigación Biomédica en Red. Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
| | - Ana García-Álvarez
- Arrhythmias Unit, Hospital Clinic, University of Barcelona-IDIBAPS, Barcelona, Spain.,Centro de Investigación Biomédica en Red. Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
| | | | | | - Victoria Fiol
- Arrhythmias Unit, Hospital Sant Joan de Déu, University of Barcelona, Barcelona, Spain
| | - Josep Brugada
- Arrhythmias Unit, Hospital Sant Joan de Déu, University of Barcelona, Barcelona, Spain.,Arrhythmias Unit, Hospital Clinic, University of Barcelona-IDIBAPS, Barcelona, Spain.,Centro de Investigación Biomédica en Red. Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
| | - Ramon Brugada
- Medical Science Department, School of Medicine, University of Girona, Girona, Spain.,Cardiovascular Genetics Center, University of Girona-IDIBGI, Girona, Spain.,Centro de Investigación Biomédica en Red. Enfermedades Cardiovasculares (CIBERCV), Madrid, 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 de Investigación Biomédica en Red. Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
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11
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Cacheux M, Fauconnier J, Thireau J, Osseni A, Brocard J, Roux-Buisson N, Brocard J, Fauré J, Lacampagne A, Marty I. Interplay between Triadin and Calsequestrin in the Pathogenesis of CPVT in the Mouse. Mol Ther 2019; 28:171-179. [PMID: 31607542 DOI: 10.1016/j.ymthe.2019.09.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 08/28/2019] [Accepted: 09/06/2019] [Indexed: 01/07/2023] Open
Abstract
Recessive forms of catecholaminergic polymorphic ventricular tachycardia (CPVT) are induced by mutations in genes encoding triadin or calsequestrin, two proteins that belong to the Ca2+ release complex, responsible for intracellular Ca2+ release triggering cardiac contractions. To better understand the mechanisms of triadin-induced CPVT and to assay multiple therapeutic interventions, we used a triadin knockout mouse model presenting a CPVT-like phenotype associated with a decrease in calsequestrin protein level. We assessed different approaches to rescue protein expression and to correct intracellular Ca2+ release and cardiac function: pharmacological treatment with kifunensine or a viral gene transfer-based approach, using adeno-associated virus serotype 2/9 (AAV2/9) encoding the triadin or calsequestrin. We observed that the levels of triadin and calsequestrin are intimately linked, and that reduction of both proteins contributes to the CPVT phenotype. Different combinations of triadin and calsequestrin expression level were obtained using these therapeutic approaches. A full expression of each is not necessary to correct the phenotype; a fine-tuning of the relative re-expression of both triadin and calsequestrin is required to correct the CPVT phenotype and rescue the cardiac function. AAV-mediated gene delivery of calsequestrin or triadin and treatment with kifunensine are potential treatments for recessive forms of CPVT due to triadin mutations.
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Affiliation(s)
- Marine Cacheux
- Grenoble Institut Neurosciences, INSERM, Grenoble Alpes University, U1216, CHU Grenoble Alpes, 38700 La Tronche, France
| | - Jérémy Fauconnier
- University of Montpellier, INSERM U1046, CNRS 9214, CHU Montpellier, 34295 Montpellier, France
| | - Jérôme Thireau
- University of Montpellier, INSERM U1046, CNRS 9214, CHU Montpellier, 34295 Montpellier, France
| | - Alexis Osseni
- Grenoble Institut Neurosciences, INSERM, Grenoble Alpes University, U1216, CHU Grenoble Alpes, 38700 La Tronche, France
| | - Jacques Brocard
- Grenoble Institut Neurosciences, INSERM, Grenoble Alpes University, U1216, CHU Grenoble Alpes, 38700 La Tronche, France
| | - Nathalie Roux-Buisson
- Grenoble Institut Neurosciences, INSERM, Grenoble Alpes University, U1216, CHU Grenoble Alpes, 38700 La Tronche, France
| | - Julie Brocard
- Grenoble Institut Neurosciences, INSERM, Grenoble Alpes University, U1216, CHU Grenoble Alpes, 38700 La Tronche, France
| | - Julien Fauré
- Grenoble Institut Neurosciences, INSERM, Grenoble Alpes University, U1216, CHU Grenoble Alpes, 38700 La Tronche, France
| | - Alain Lacampagne
- University of Montpellier, INSERM U1046, CNRS 9214, CHU Montpellier, 34295 Montpellier, France.
| | - Isabelle Marty
- Grenoble Institut Neurosciences, INSERM, Grenoble Alpes University, U1216, CHU Grenoble Alpes, 38700 La Tronche, France.
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12
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Rossi D, Gigli L, Gamberucci A, Bordoni R, Pietrelli A, Lorenzini S, Pierantozzi E, Peretto G, De Bellis G, Della Bella P, Ferrari M, Sorrentino V, Benedetti S, Sala S, Di Resta C. A novel homozygous mutation in the TRDN gene causes a severe form of pediatric malignant ventricular arrhythmia. Heart Rhythm 2019; 17:296-304. [PMID: 31437535 DOI: 10.1016/j.hrthm.2019.08.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Indexed: 12/26/2022]
Abstract
BACKGROUND Triadin is a protein expressed in cardiac and skeletal muscle that has an essential role in the structure and functional regulation of calcium release units and excitation-contraction coupling. Mutations in the triadin gene (TRDN) have been described in different forms of human arrhythmia syndromes with early onset and severe arrhythmogenic phenotype, including triadin knockout syndrome. OBJECTIVE The purpose of this study was to characterize the pathogenetic mechanism underlying a case of severe pediatric malignant arrhythmia associated with a defect in the TRDN gene. METHODS We used a trio whole exome sequencing approach to identify the genetic defect in a 2-year-old boy who had been resuscitated from sudden cardiac arrest and had frequent episodes of ventricular fibrillation and a family history positive for sudden death. We then performed in vitro functional analysis to investigate possible pathogenic mechanisms underlying this severe phenotype. RESULTS We identified a novel homozygous missense variant (p.L56P) in the TRDN gene in the proband that was inherited from the heterozygous unaffected parents. Expression of a green fluorescent protein (GFP)-tagged mutant human cardiac triadin isoform (TRISK32-L56P-GFP) in heterologous systems revealed that the mutation alters protein dynamics. Furthermore, when co-expressed with the type 2 ryanodine receptor, caffeine-induced calcium release from TRISK32-L56P-GFP was relatively lower compared to that observed with the wild-type construct. CONCLUSION The results of this study allowed us to hypothesize a pathogenic mechanism underlying this rare arrhythmogenic recessive form, suggesting that the mutant protein potentially can trigger arrhythmias by altering calcium homeostasis.
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Affiliation(s)
- Daniela Rossi
- Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
| | - Lorenzo Gigli
- Department of Arrhythmology, IRCCS San Raffaele Hospital, Milan, Italy
| | - Alessandra Gamberucci
- Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
| | - Roberta Bordoni
- Institute of Biomedical Technologies, National Research Council of Italy, Milan, Italy
| | - Alessandro Pietrelli
- Institute of Biomedical Technologies, National Research Council of Italy, Milan, Italy
| | - Stefania Lorenzini
- Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
| | - Enrico Pierantozzi
- Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
| | - Giovanni Peretto
- Department of Arrhythmology, IRCCS San Raffaele Hospital, Milan, Italy
| | - Gianluca De Bellis
- Institute of Biomedical Technologies, National Research Council of Italy, Milan, Italy
| | - Paolo Della Bella
- Department of Arrhythmology, IRCCS San Raffaele Hospital, Milan, Italy
| | - Maurizio Ferrari
- Vita-Salute San Raffaele University, Milan, Italy; Laboratory of Clinical Molecular Biology and Cytogenetics, IRCCS San Raffaele Hospital, Milan, Italy; Genomic Unit for the Diagnosis of Human Pathologies, Division of Genetics and Cellular Biology, IRCCS San Raffaele Hospital, Milan, Italy
| | - Vincenzo Sorrentino
- Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
| | - Sara Benedetti
- Laboratory of Clinical Molecular Biology and Cytogenetics, IRCCS San Raffaele Hospital, Milan, Italy
| | - Simone Sala
- Department of Arrhythmology, IRCCS San Raffaele Hospital, Milan, Italy
| | - Chiara Di Resta
- Vita-Salute San Raffaele University, Milan, Italy; Genomic Unit for the Diagnosis of Human Pathologies, Division of Genetics and Cellular Biology, IRCCS San Raffaele Hospital, Milan, Italy.
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13
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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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14
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O’Callaghan BM, Hancox JC, Stuart AG, Armstrong C, Williams MM, Hills A, Pearce H, Dent CL, Gable M, Walsh MA. A unique triadin exon deletion causing a null phenotype. HeartRhythm Case Rep 2018; 4:514-518. [PMID: 30479949 PMCID: PMC6241331 DOI: 10.1016/j.hrcr.2018.07.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
| | - Jules C. Hancox
- School of Physiology and Pharmacology, Cardiovascular Research Laboratories, University of Bristol, Bristol, United Kingdom
| | - Alan G. Stuart
- Bristol Royal Hospital for Children, Bristol, United Kingdom
| | | | - Maggie M. Williams
- Genomic Diagnostics Laboratory, University Hospital Bristol, Bristol, United Kingdom
| | - Alison Hills
- Genomic Diagnostics Laboratory, University Hospital Bristol, Bristol, United Kingdom
| | - Hazel Pearce
- Genomic Diagnostics Laboratory, University Hospital Bristol, Bristol, United Kingdom
| | - Carolyn L. Dent
- Genomic Diagnostics Laboratory, University Hospital Bristol, Bristol, United Kingdom
| | - Mary Gable
- Genomic Diagnostics Laboratory, University Hospital Bristol, Bristol, United Kingdom
| | - Mark A. Walsh
- Bristol Royal Hospital for Children, Bristol, United Kingdom
- Address reprint requests and correspondence: Dr Mark A. Walsh, Our Lady's Children's Hospital, Crumlin, Cooley Road, Drimnagh, Dublin, Ireland.
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15
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Abstract
During the complex series of events leading to muscle contraction, the initial electric signal coming from motor neurons is transformed into an increase in calcium concentration that triggers sliding of myofibrils. This process, referred to as excitation-contraction coupling, is reliant upon the calcium-release complex, which is restricted spatially to a sub-compartment of muscle cells ("the triad") and regulated precisely. Any dysfunction in the calcium-release complex leads to muscle impairment and myopathy. Various causes can lead to alterations in excitation-contraction coupling and to muscle diseases. The latter are reviewed and classified into four categories: (i) mutation in a protein of the calcium-release complex; (ii) alteration in triad structure; (iii) modification of regulation of channels; (iv) modification in calcium stores within the muscle. Current knowledge of the pathophysiologic mechanisms in each category is described and discussed.
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Affiliation(s)
- Isabelle Marty
- University Grenoble Alpes, Grenoble Institut des Neurosciences, GIN, F-38000 Grenoble, France.,INSERM, U1216, F-38000 Grenoble, France
| | - Julien Fauré
- University Grenoble Alpes, Grenoble Institut des Neurosciences, GIN, F-38000 Grenoble, France.,INSERM, U1216, F-38000 Grenoble, France.,CHU de Grenoble, F-38000 Grenoble, France
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16
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Hancox JC, James AF, Walsh MA, Stuart AG. Triadin mutations - a cause of ventricular arrhythmias in children and young adults. JOURNAL OF CONGENITAL CARDIOLOGY 2017. [DOI: 10.1186/s40949-017-0011-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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17
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Engel AG, Redhage KR, Tester DJ, Ackerman MJ, Selcen D. Congenital myopathy associated with the triadin knockout syndrome. Neurology 2017; 88:1153-1156. [PMID: 28202702 DOI: 10.1212/wnl.0000000000003745] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 12/27/2016] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE Triadin is a component of the calcium release complex of cardiac and skeletal muscle. Our objective was to analyze the skeletal muscle phenotype of the triadin knockout syndrome. METHODS We performed clinical evaluation, analyzed morphologic features by light and electron microscopy, and immunolocalized triadin in skeletal muscle. RESULTS A 6-year-old boy with lifelong muscle weakness had a triadin knockout syndrome caused by compound heterozygous null mutations in triadin. Light microscopy of a deltoid muscle specimen shows multiple small abnormal spaces in all muscle fibers. Triadin immunoreactivity is absent from type 1 fibers and barely detectable in type 2 fibers. Electron microscopy reveals focally distributed dilation and degeneration of the lateral cisterns of the sarcoplasmic reticulum and loss of the triadin anchors from the preserved lateral cisterns. CONCLUSIONS Absence of triadin in humans can result in a congenital myopathy associated with profound pathologic alterations in components of the sarcoplasmic reticulum. Why only some triadin-deficient patients develop a skeletal muscle phenotype remains an unsolved question.
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Affiliation(s)
- Andrew G Engel
- From the Departments of Neurology and Muscle Research Laboratory (A.G.E., D.S.), Cardiovascular Diseases/Division of Heart Rhythm Services (A.G.E., D.S.), Pediatric and Adolescent Medicine/Division of Pediatric Cardiology (K.R.R., D.J.T., M.J.A.), and Molecular Pharmacology & Experimental Therapeutics/Windland Smith Rice Sudden Death Genomics Laboratory (K.R.R., D.J.T., M.J.A.), Mayo College of Medicine, Rochester, MN.
| | - Keeley R Redhage
- From the Departments of Neurology and Muscle Research Laboratory (A.G.E., D.S.), Cardiovascular Diseases/Division of Heart Rhythm Services (A.G.E., D.S.), Pediatric and Adolescent Medicine/Division of Pediatric Cardiology (K.R.R., D.J.T., M.J.A.), and Molecular Pharmacology & Experimental Therapeutics/Windland Smith Rice Sudden Death Genomics Laboratory (K.R.R., D.J.T., M.J.A.), Mayo College of Medicine, Rochester, MN
| | - David J Tester
- From the Departments of Neurology and Muscle Research Laboratory (A.G.E., D.S.), Cardiovascular Diseases/Division of Heart Rhythm Services (A.G.E., D.S.), Pediatric and Adolescent Medicine/Division of Pediatric Cardiology (K.R.R., D.J.T., M.J.A.), and Molecular Pharmacology & Experimental Therapeutics/Windland Smith Rice Sudden Death Genomics Laboratory (K.R.R., D.J.T., M.J.A.), Mayo College of Medicine, Rochester, MN
| | - Michael J Ackerman
- From the Departments of Neurology and Muscle Research Laboratory (A.G.E., D.S.), Cardiovascular Diseases/Division of Heart Rhythm Services (A.G.E., D.S.), Pediatric and Adolescent Medicine/Division of Pediatric Cardiology (K.R.R., D.J.T., M.J.A.), and Molecular Pharmacology & Experimental Therapeutics/Windland Smith Rice Sudden Death Genomics Laboratory (K.R.R., D.J.T., M.J.A.), Mayo College of Medicine, Rochester, MN
| | - Duygu Selcen
- From the Departments of Neurology and Muscle Research Laboratory (A.G.E., D.S.), Cardiovascular Diseases/Division of Heart Rhythm Services (A.G.E., D.S.), Pediatric and Adolescent Medicine/Division of Pediatric Cardiology (K.R.R., D.J.T., M.J.A.), and Molecular Pharmacology & Experimental Therapeutics/Windland Smith Rice Sudden Death Genomics Laboratory (K.R.R., D.J.T., M.J.A.), Mayo College of Medicine, Rochester, MN
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