1
|
Goebel HH, Stenzel W. A brief history of the congenital myopathies - the myopathological perspective. Neuromuscul Disord 2023; 33:990-995. [PMID: 37980206 DOI: 10.1016/j.nmd.2023.10.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 09/23/2023] [Accepted: 10/13/2023] [Indexed: 11/20/2023]
Abstract
Congenital myopathies are defined by early clinical onset, slow progression, hereditary nature and disease-specific myopathological lesions - however, with exceptions - demanding special techniques in regard to morphological diagnostic and research work-up. To identify an index disease in a family requires a muscle biopsy - and no congenital myopathy has ever been first described at autopsy. The nosographic history commenced when - in addition to special histopathological techniques in the earliest classical triad of central core disease, 1956, nemaline myopathy, 1963, and centronuclear myopathy, 1966/67, within a decade - electron microscopy and enzyme histochemistry were applied to unfixed frozen muscle tissue and, thus, revolutionized diagnostic and research myopathology. During the following years, the list of structure-defined congenital myopathies grew to some 40 conditions. Then, the introduction of immunohistochemistry allowed myopathological documentation of proteins and their abnormalities in individual congenital myopathies. Together with the diagnostic evolution of molecular genetics, many more congenital myopathies were described, without new disease-specific lesions or only already known ones. These were nosographically defined by individual mutations in hitherto congenital myopathies-unrelated genes. This latter development may also affect the nomenclature of congenital myopathies in that the mutant gene needs to be attached to the individually identified congenital myopathies with or without the disease-specific lesion, such as CCD-RYR1 or CM-RYR1. This principle is similar to that of the nomenclature of Congenital Disorders of Glycosylation. Retroactive molecular characterization of originally and first described congenital myopathies has only rarely been achieved.
Collapse
Affiliation(s)
- Hans H Goebel
- Institute of Neuropathology, Charite Universitätsmedizin, Berlin, Germany; Department of Neuropathology, Universitätsmedizin, Mainz, Germany.
| | - Werner Stenzel
- Institute of Neuropathology, Charite Universitätsmedizin, Berlin, Germany
| |
Collapse
|
2
|
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.
Collapse
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.
| |
Collapse
|
3
|
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.
Collapse
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
| |
Collapse
|
4
|
Quantification of the calcium signaling deficit in muscles devoid of triadin. PLoS One 2022; 17:e0264146. [PMID: 35213584 PMCID: PMC8880904 DOI: 10.1371/journal.pone.0264146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Accepted: 02/03/2022] [Indexed: 11/24/2022] Open
Abstract
Triadin, a protein of the sarcoplasmic reticulum (SR) of striated muscles, anchors the calcium-storing protein calsequestrin to calcium release RyR channels at the junction with t-tubules, and modulates these channels by conformational effects. Triadin ablation induces structural SR changes and alters the expression of other proteins. Here we quantify alterations of calcium signaling in single skeletal myofibers of constitutive triadin-null mice. We find higher resting cytosolic and lower SR-luminal [Ca2+], 40% lower calsequestrin expression, and more CaV1.1, RyR1 and SERCA1. Despite the increased CaV1.1, the mobile intramembrane charge was reduced by ~20% in Triadin-null fibers. The initial peak of calcium release flux by pulse depolarization was minimally altered in the null fibers (revealing an increase in peak calcium permeability). The “hump” phase that followed, attributable to calcium detaching from calsequestrin, was 25% lower, a smaller change than expected from the reduced calsequestrin content and calcium saturation. The exponential decay rate of calcium transients was 25% higher, consistent with the higher SERCA1 content. Recovery of calcium flux after a depleting depolarization was faster in triadin-null myofibers, consistent with the increased uptake rate and lower SR calsequestrin content. In sum, the triadin knockout determines an increased RyR1 channel openness, which depletes the SR, a substantial loss of calsequestrin and gains in other couplon proteins. Powerful functional compensations ensue: activation of SOCE that increases [Ca2+]cyto; increased SERCA1 activity, which limits the decrease in [Ca2+]SR and a restoration of SR calcium storage of unknown substrate. Together, they effectively limit the functional loss in skeletal muscles.
Collapse
|
5
|
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.
Collapse
|
6
|
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.
Collapse
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.)
| |
Collapse
|
7
|
Schartner V, Laporte J, Böhm J. Abnormal Excitation-Contraction Coupling and Calcium Homeostasis in Myopathies and Cardiomyopathies. J Neuromuscul Dis 2020; 6:289-305. [PMID: 31356215 DOI: 10.3233/jnd-180314] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Muscle contraction requires specialized membrane structures with precise geometry and relies on the concerted interplay of electrical stimulation and Ca2+ release, known as excitation-contraction coupling (ECC). The membrane structure hosting ECC is called triad in skeletal muscle and dyad in cardiac muscle, and structural or functional defects of triads and dyads have been observed in a variety of myopathies and cardiomyopathies. Based on their function, the proteins localized at the triad/dyad can be classified into three molecular pathways: the Ca2+ release complex (CRC), store-operated Ca2+ entry (SOCE), and membrane remodeling. All three are mechanistically linked, and consequently, aberrations in any of these pathways cause similar disease entities. This review provides an overview of the clinical and genetic spectrum of triad and dyad defects with a main focus of attention on the underlying pathomechanisms.
Collapse
Affiliation(s)
- Vanessa Schartner
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France.,INSERM U1258, Illkirch, France.,CNRS UMR7104, Illkirch, France.,Strasbourg University, Illkirch, France
| | - Jocelyn Laporte
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France.,INSERM U1258, Illkirch, France.,CNRS UMR7104, Illkirch, France.,Strasbourg University, Illkirch, France
| | - Johann Böhm
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France.,INSERM U1258, Illkirch, France.,CNRS UMR7104, Illkirch, France.,Strasbourg University, Illkirch, France
| |
Collapse
|
8
|
Radke J, Stenzel W, Goebel HH. Corrigendum to "Recently Identified Congenital Myopathies" [Semin Pediatr Neurol 29 (2019) 83-90]. Semin Pediatr Neurol 2019; 32:100775. [PMID: 31813515 DOI: 10.1016/j.spen.2019.100775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- Josefine Radke
- Department of Neuropathology, Charite - Universitätsmedizin Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.
| | - Werner Stenzel
- Department of Neuropathology, Charite - Universitätsmedizin Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Hans H Goebel
- Department of Neuropathology, Charite - Universitätsmedizin Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| |
Collapse
|
9
|
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.
Collapse
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.
| |
Collapse
|
10
|
Abstract
Congenital myopathies (CM) are a large and heterogeneous group of disorders. Many new myopathies with congenital onset have recently been described phenotypically, and their molecular elucidation has rapidly ensued consecutively. CM reported between 2013 and 2017 and their corresponding gene defects have mostly been identified with modern molecular genetic techniques. Here, we report recently identified CM that have not been included in the 2017 gene table so far, of which some have been recognized with mutations in new genes and others have been recognized as variants of previously identified genes, associated with specific CM phenotypes.
Collapse
Affiliation(s)
- Josefine Radke
- Department of Neuropathology, Charité-Universitätsmedizin Berlin, Berlin, Germany.
| | - Werner Stenzel
- Department of Neuropathology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Hans H Goebel
- Department of Neuropathology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| |
Collapse
|
11
|
Ravenscroft G, Bryson-Richardson RJ, Nowak KJ, Laing NG. Recent advances in understanding congenital myopathies. F1000Res 2018; 7. [PMID: 30631434 PMCID: PMC6290972 DOI: 10.12688/f1000research.16422.1] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/29/2018] [Indexed: 12/18/2022] Open
Abstract
By definition, congenital myopathy typically presents with skeletal muscle weakness and hypotonia at birth. Traditionally, congenital myopathy subtypes have been predominantly distinguished on the basis of the pathological hallmarks present on skeletal muscle biopsies. Many genes cause congenital myopathies when mutated, and a burst of new causative genes have been identified because of advances in gene sequencing technology. Recent discoveries include extending the disease phenotypes associated with previously identified genes and determining that genes formerly known to cause only dominant disease can also cause recessive disease. The more recently identified congenital myopathy genes account for only a small proportion of patients. Thus, the congenital myopathy genes remaining to be discovered are predicted to be extremely rare causes of disease, which greatly hampers their identification. Significant progress in the provision of molecular diagnoses brings important information and value to patients and their families, such as possible disease prognosis, better disease management, and informed reproductive choice, including carrier screening of parents. Additionally, from accurate genetic knowledge, rational treatment options can be hypothesised and subsequently evaluated
in vitro and in animal models. A wide range of potential congenital myopathy therapies have been investigated on the basis of improved understanding of disease pathomechanisms, and some therapies are in clinical trials. Although large hurdles remain, promise exists for translating treatment benefits from preclinical models to patients with congenital myopathy, including harnessing proven successes for other genetic diseases.
Collapse
Affiliation(s)
- Gianina Ravenscroft
- Centre for Medical Research, The University of Western Australia, Perth, WA, Australia.,Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, WA, Australia
| | | | - Kristen J Nowak
- Centre for Medical Research, The University of Western Australia, Perth, WA, Australia.,Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, WA, Australia.,School of Biological Sciences, Faculty of Health and Medical Sciences, The University of Western Australia, QEII Medical Centre, Nedlands, WA, Australia.,Office of Population Health Genomics, Western Australian Department of Health, East Perth, WA, Australia
| | - Nigel G Laing
- Centre for Medical Research, The University of Western Australia, Perth, WA, Australia.,Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, WA, Australia.,Department of Diagnostic Genomics, PathWest Laboratory Medicine, QEII Medical Centre, Nedlands, WA, Australia
| |
Collapse
|
12
|
Schiaffino S. Knockout of human muscle genes revealed by large scale whole-exome studies. Mol Genet Metab 2018; 123:411-415. [PMID: 29452748 DOI: 10.1016/j.ymgme.2018.02.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2017] [Revised: 02/06/2018] [Accepted: 02/06/2018] [Indexed: 12/22/2022]
Abstract
Large scale whole-exome sequence studies have revealed that a number of individuals from different populations have predicted loss-of-function of different genes due to nonsense, frameshift, or canonical splice-site mutations. Surprisingly, many of these mutations do not apparently show the deleterious phenotypic consequences expected from gene knockout. These homozygous null mutations, when confirmed, can provide insight into human gene function and suggest novel approaches to correct gene dysfunction, as the lack of the expected disease phenotype may reflect the existence of modifier genes that reveal potential therapeutic targets. Human knockouts complement the information derived from mouse knockouts, which are not always good models of human disease. We have examined human knockout datasets searching for genes expressed exclusively or predominantly in striated muscle. A number of well-known muscle genes was found in one or more datasets, including genes coding for sarcomeric myosins, components of the sarcomeric cytoskeleton, sarcoplasmic reticulum and plasma membrane, and enzymes involved in muscle metabolism. The surprising absence of phenotype in some of these human knockouts is critically discussed, focusing on the comparison with the corresponding mouse knockouts.
Collapse
|
13
|
Congenital myopathies: disorders of excitation-contraction coupling and muscle contraction. Nat Rev Neurol 2018; 14:151-167. [PMID: 29391587 DOI: 10.1038/nrneurol.2017.191] [Citation(s) in RCA: 178] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The congenital myopathies are a group of early-onset, non-dystrophic neuromuscular conditions with characteristic muscle biopsy findings, variable severity and a stable or slowly progressive course. Pronounced weakness in axial and proximal muscle groups is a common feature, and involvement of extraocular, cardiorespiratory and/or distal muscles can implicate specific genetic defects. Central core disease (CCD), multi-minicore disease (MmD), centronuclear myopathy (CNM) and nemaline myopathy were among the first congenital myopathies to be reported, and they still represent the main diagnostic categories. However, these entities seem to belong to a much wider phenotypic spectrum. To date, congenital myopathies have been attributed to mutations in over 20 genes, which encode proteins implicated in skeletal muscle Ca2+ homeostasis, excitation-contraction coupling, thin-thick filament assembly and interactions, and other mechanisms. RYR1 mutations are the most frequent genetic cause, and CCD and MmD are the most common subgroups. Next-generation sequencing has vastly improved mutation detection and has enabled the identification of novel genetic backgrounds. At present, management of congenital myopathies is largely supportive, although new therapeutic approaches are reaching the clinical trial stage.
Collapse
|