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Marinakis NM, Svingou M, Papadimas GK, Papadopoulos C, Chroni E, Pons R, Pavlou E, Sarmas I, Kosma K, Apostolou P, Sofocleous C, Traeger-Synodinos J, Kekou K. Myotonia congenita in a Greek cohort: Genotype spectrum and impact of the CLCN1:c.501C > G variant as a genetic modifier. Muscle Nerve 2024; 70:240-247. [PMID: 38855810 DOI: 10.1002/mus.28180] [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: 10/25/2023] [Revised: 05/18/2024] [Accepted: 05/24/2024] [Indexed: 06/11/2024]
Abstract
INTRODUCTION/AIMS Myotonia congenita (MC) is the most common hereditary channelopathy in humans. Characterized by muscle stiffness, MC may be transmitted as either an autosomal dominant (Thomsen) or a recessive (Becker) disorder. MC is caused by variants in the voltage-gated chloride channel 1 (CLCN1) gene, important for the normal repolarization of the muscle action potential. More than 250 disease-causing variants in the CLCN1 gene have been reported. This study provides an MC genotype-phenotype spectrum in a large cohort of Greek patients and focuses on novel variants and disease epidemiology, including additional insights for the variant CLCN1:c.501C > G. METHODS Sanger sequencing for the entire coding region of the CLCN1 gene was performed. Targeted segregation analysis of likely candidate variants in additional family members was performed. Variant classification was based on American College of Medical Genetics (ACMG) guidelines. RESULTS Sixty-one patients from 47 unrelated families were identified, consisting of 51 probands with Becker MC (84%) and 10 with Thomsen MC (16%). Among the different variants detected, 11 were novel and 16 were previously reported. The three most prevalent variants were c.501C > G, c.2680C > T, and c.1649C > G. Additionally, c.501C > G was detected in seven Becker cases in-cis with the c.1649C > G. DISCUSSION The large number of patients in whom a diagnosis was established allowed the characterization of genotype-phenotype correlations with respect to both previously reported and novel findings. For the c.501C > G (p.Phe167Leu) variant a likely nonpathogenic property is suggested, as it only seems to act as an aggravating modifying factor in cases in which a pathogenic variant triggers phenotypic expression.
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Affiliation(s)
- Nikolaos M Marinakis
- Laboratory of Medical Genetics, Medical School, St. Sophia's Children's Hospital, National and Kapodistrian University of Athens, Athens, Greece
- Research University Institute for the Study and Prevention of Genetic and Malignant Disease of Childhood, St. Sophia's Children's Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Maria Svingou
- Laboratory of Medical Genetics, Medical School, St. Sophia's Children's Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Giorgos-Konstantinos Papadimas
- Department of Neurology, Eginition Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Constantinos Papadopoulos
- Department of Neurology, Eginition Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Elisabeth Chroni
- Department of Neurology, School of Medicine, University of Patras, Rio-Patras, Greece
| | - Roser Pons
- First Department of Pediatrics, Medical School, St. Sophia's Children's Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Evangelos Pavlou
- Department of Pediatrics, School of Medicine, Aristotle University of Thessaloniki, University General Hospital AHEPA, Thessaloniki, Greece
| | - Ioannis Sarmas
- Department of Neurology, Faculty of Medicine, University of Ioannina, Ioannina, Greece
| | - Konstantina Kosma
- Laboratory of Medical Genetics, Medical School, St. Sophia's Children's Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Paraskevi Apostolou
- Human Molecular Genetics Laboratory, INRaSTES, National Center for Scientific Research "Demokritos", Athens, Greece
| | - Christalena Sofocleous
- Laboratory of Medical Genetics, Medical School, St. Sophia's Children's Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Joanne Traeger-Synodinos
- Laboratory of Medical Genetics, Medical School, St. Sophia's Children's Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Kyriaki Kekou
- Laboratory of Medical Genetics, Medical School, St. Sophia's Children's Hospital, National and Kapodistrian University of Athens, Athens, Greece
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2
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Vacchiano V, Brugnoni R, Campanale C, Imbrici P, Dinoi G, Canioni E, Laghetti P, Saltarella I, Altamura C, Maggi L, Liguori R, Donadio V, Desaphy JF. Coexistence of SCN4A and CLCN1 mutations in a family with atypical myotonic features: A clinical and functional study. Exp Neurol 2023; 362:114342. [PMID: 36720299 DOI: 10.1016/j.expneurol.2023.114342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Revised: 01/12/2023] [Accepted: 01/26/2023] [Indexed: 01/30/2023]
Abstract
Non-dystrophic myotonias include several entities with possible clinical overlap, i.e. myotonia congenita caused by CLCN1 gene mutations, as well as paramyotonia congenita and sodium channel myotonia caused by SCN4A gene mutations. Herein, we describe the clinical features of five relatives affected by clinical and neurophysiological myotonia, with an aspecific and mixed phenotype. Next-generation sequencing identified the novel p.K1302R variant in SCN4A and the p.H838P variant in CLCN1. Segregation of the two mutations with the disease was confirmed by genotyping affected and non-affected family members. Patch-clamp experiments showed that sodium currents generated by p.K1302R and WT hNav1.4 were very similar. Mutant channel showed a small negative shift (5 mV) in the voltage-dependence of activation, which increased the likelihood of the channel to open at more negative voltages. The p.H838P mutation caused a reduction in chloride current density and a small voltage-dependence shift towards less negative potentials, in agreement with its position into the CBS2 domain of the C-terminus. Our results demonstrated that the mild functional alterations induced by p.K1302R and p.H838P in combination may be responsible for the mixed myotonic phenotypes. The K1302R mutant was sensitive to mexiletine and lamotrigine, suggesting that both drugs might be useful for the K1302R carriers.
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Affiliation(s)
- Veria Vacchiano
- IRCSS Istituto delle Scienze Neurologiche di Bologna, Bologna, Italy.
| | - Raffaella Brugnoni
- Neuroimmunology and Neuromuscular Diseases Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Italy
| | - Carmen Campanale
- Dept. of Precision and Regenerative Medicine, School of Medicine, University of Bari Aldo Moro, Bari, Italy
| | - Paola Imbrici
- Dept. of Pharmacy - Drug Sciences, University of Bari Aldo Moro, Bari, Italy
| | - Giorgia Dinoi
- Dept. of Pharmacy - Drug Sciences, University of Bari Aldo Moro, Bari, Italy
| | - Eleonora Canioni
- Neuroimmunology and Neuromuscular Diseases Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Italy
| | - Paola Laghetti
- Dept. of Precision and Regenerative Medicine, School of Medicine, University of Bari Aldo Moro, Bari, Italy
| | - Ilaria Saltarella
- Dept. of Precision and Regenerative Medicine, School of Medicine, University of Bari Aldo Moro, Bari, Italy
| | - Concetta Altamura
- Dept. of Precision and Regenerative Medicine, School of Medicine, University of Bari Aldo Moro, Bari, Italy
| | - Lorenzo Maggi
- Neuroimmunology and Neuromuscular Diseases Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Italy
| | - Rocco Liguori
- IRCSS Istituto delle Scienze Neurologiche di Bologna, Bologna, Italy
| | - Vincenzo Donadio
- IRCSS Istituto delle Scienze Neurologiche di Bologna, Bologna, Italy
| | - Jean-François Desaphy
- Dept. of Precision and Regenerative Medicine, School of Medicine, University of Bari Aldo Moro, Bari, Italy
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Pagliarani S, Meola G, Filareti M, Comi GP, Lucchiari S. Case report: Sodium and chloride muscle channelopathy coexistence: A complicated phenotype and a challenging diagnosis. Front Neurol 2022; 13:845383. [PMID: 36081873 PMCID: PMC9447429 DOI: 10.3389/fneur.2022.845383] [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: 12/29/2021] [Accepted: 07/19/2022] [Indexed: 11/13/2022] Open
Abstract
Non-dystrophic myotonias (NDM) encompass chloride and sodium channelopathy. Mutations in CLCN1 lead to either the autosomal dominant form or the recessive form of myotonia congenita (MC). The main symptom is stiffness worsening after rest and improving by physical exercise. Patients with recessive mutations often show muscle hypertrophy, and transient weakness mostly in their lower limbs. Mutations in SCN4A can lead to Hyper-, Hypo- or Normo-kalemic Periodic Paralysis or to different forms of myotonia (Paramyotonia Congenita-PMC and Sodium Channel Myotonia-SCM and severe neonatal episodic laryngospasm-SNEL). SCM often presents facial muscle stiffness, cold sensitivity, and muscle pain, whereas myotonia worsens in PMC patients with the repetition of the muscle activity and cold. Patients affected by chloride or sodium channelopathies may show similar phenotypes and symptoms, making the diagnosis more difficult to reach. Herein we present a woman in whom sodium and chloride channelopathies coexist yielding a complex phenotype with features typical of both MC and PMC. Disease onset was in the second decade with asthenia, weakness, warm up and limb stiffness, and her symptoms had been worsening through the years leading to frequent heavy retrosternal compression, tachycardia, stiffness, and symmetrical pain in her lower limbs. She presented severe lid lag myotonia, a hypertrophic appearance at four limbs and myotonic discharges at EMG. Her symptoms have been triggered by exposure to cold and her daily life was impaired. All together, clinical signs and instrumental data led to the hypothesis of PMC and to the administration of mexiletine, then replaced by acetazolamide because of gastrointestinal side effects. Analysis of SCN4A revealed a new variant, p.Glu1607del. Nonetheless the severity of myotonia in the lower limbs and her general stiffness led to hypothesize that the impairment of sodium channel, Nav1.4, alone could not satisfactorily explain the phenotype and a second genetic “factor” was hypothesized. CLCN1 was targeted, and p.Met485Val was detected in homozygosity. This case highlights that proper identification of signs and symptoms by an expert neurologist is crucial to target a successful genetic diagnosis and appropriate therapy.
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Affiliation(s)
- Serena Pagliarani
- Department of Neurological Sciences, Dino Ferrari Centre, IRCCS Fondazione Ca' Granda Ospedale Maggiore Policlinico, University of Milan, Milan, Italy
| | - Giovanni Meola
- Department of Biomedical Sciences for Health, University of Milano, Milan, Italy
- Department of Neurorehabilitation Sciences Casa di Cura del Policlinico, Milan, Italy
| | - Melania Filareti
- Department of Neurorehabilitation Sciences Casa di Cura del Policlinico, Milan, Italy
| | - Giacomo Pietro Comi
- Department of Neurological Sciences, Dino Ferrari Centre, IRCCS Fondazione Ca' Granda Ospedale Maggiore Policlinico, University of Milan, Milan, Italy
| | - Sabrina Lucchiari
- Department of Neurological Sciences, Dino Ferrari Centre, IRCCS Fondazione Ca' Granda Ospedale Maggiore Policlinico, University of Milan, Milan, Italy
- *Correspondence: Sabrina Lucchiari
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Genetic spectrum and founder effect of non-dystrophic myotonia: a Japanese case series study. J Neurol 2022; 269:6406-6415. [PMID: 35907044 DOI: 10.1007/s00415-022-11305-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 07/20/2022] [Accepted: 07/21/2022] [Indexed: 10/16/2022]
Abstract
Non-dystrophic myotonias (NDM) are rare skeletal muscle channelopathies, mainly linked to two voltage-gated ion channel genes, CLCN1 and SCN4A. The aim of this study is to identify the clinical and genetic features of patients with NDM in Japan. We collected a Japanese nationwide case series of patients with clinical diagnosis of NDM (1999-2021). Among 71 out of 88 pedigrees, using Sanger and next-generation sequencing targeting both CLCN1 and SCN4A genes, variants classified as pathogenic/likely pathogenic/unknown significance were detected from CLCN1 (31 probands), SCN4A (36 probands), or both genes (4 probands), and 11 of them were novel. Pedigrees carrying mono-allelic CLCN1 variants were more commonly seen than that with bi-allelic/double variants (24:7). Compared to patients with CLCN1 variants, patients harboring SCN4A variants showed younger onset age (5.64 ± 4.70 years vs. 9.23 ± 5.21 years), fewer warm-up phenomenon, but more paramyotonia, hyperCKemia, transient muscle weakness, and cold-induced myotonia. Haplotype analysis verified founder effects of the hot spot variants in both CLCN1 (p.T539A) and SCN4A (p.T1313M). This study reveals variants in CLCN1 and SCN4A from 80.7% of our case series, extending genetic spectrum of NDM, and would further our understanding of clinical similarity/diversity between CLCN1- and SCN4A-related NDM, as well as the genetic racial differences.
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Maggi L, Bonanno S, Altamura C, Desaphy JF. Ion Channel Gene Mutations Causing Skeletal Muscle Disorders: Pathomechanisms and Opportunities for Therapy. Cells 2021; 10:cells10061521. [PMID: 34208776 PMCID: PMC8234207 DOI: 10.3390/cells10061521] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 06/03/2021] [Accepted: 06/10/2021] [Indexed: 02/06/2023] Open
Abstract
Skeletal muscle ion channelopathies (SMICs) are a large heterogeneous group of rare genetic disorders caused by mutations in genes encoding ion channel subunits in the skeletal muscle mainly characterized by myotonia or periodic paralysis, potentially resulting in long-term disabilities. However, with the development of new molecular technologies, new genes and new phenotypes, including progressive myopathies, have been recently discovered, markedly increasing the complexity in the field. In this regard, new advances in SMICs show a less conventional role of ion channels in muscle cell division, proliferation, differentiation, and survival. Hence, SMICs represent an expanding and exciting field. Here, we review current knowledge of SMICs, with a description of their clinical phenotypes, cellular and molecular pathomechanisms, and available treatments.
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Affiliation(s)
- Lorenzo Maggi
- Neuroimmunology and Neuromuscular Disorders Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, 20133 Milan, Italy;
- Correspondence:
| | - Silvia Bonanno
- Neuroimmunology and Neuromuscular Disorders Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, 20133 Milan, Italy;
| | - Concetta Altamura
- Department of Biomedical Sciences and Human Oncology, School of Medicine, University of Bari Aldo Moro, 70124 Bari, Italy; (C.A.); (J.-F.D.)
| | - Jean-François Desaphy
- Department of Biomedical Sciences and Human Oncology, School of Medicine, University of Bari Aldo Moro, 70124 Bari, Italy; (C.A.); (J.-F.D.)
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Brugnoni R, Maggi L, Canioni E, Verde F, Gallone A, Ariatti A, Filosto M, Petrelli C, Logullo FO, Esposito M, Ruggiero L, Tonin P, Riguzzi P, Pegoraro E, Torri F, Ricci G, Siciliano G, Silani V, Merlini L, De Pasqua S, Liguori R, Pini A, Mariotti C, Moroni I, Imbrici P, Desaphy JF, Mantegazza R, Bernasconi P. Next-generation sequencing application to investigate skeletal muscle channelopathies in a large cohort of Italian patients. Neuromuscul Disord 2020; 31:336-347. [PMID: 33573884 DOI: 10.1016/j.nmd.2020.12.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 12/04/2020] [Accepted: 12/07/2020] [Indexed: 01/09/2023]
Abstract
Non-dystrophic myotonias and periodic paralyses are a heterogeneous group of disabling diseases classified as skeletal muscle channelopathies. Their genetic characterization is essential for prognostic and therapeutic purposes; however, several genes are involved. Sanger-based sequencing of a single gene is time-consuming, often expensive; thus, we designed a next-generation sequencing panel of 56 putative candidate genes for skeletal muscle channelopathies, codifying for proteins involved in excitability, excitation-contraction coupling, and metabolism of muscle fibres. We analyzed a large cohort of 109 Italian patients with a suspect of NDM or PP by next-generation sequencing. We identified 24 patients mutated in CLCN1 gene, 15 in SCN4A, 3 in both CLCN1 and SCN4A, 1 in ATP2A1, 1 in KCNA1 and 1 in CASQ1. Eight were novel mutations: p.G395Cfs*32, p.L843P, p.V829M, p.E258E and c.1471+4delTCAAGAC in CLCN1, p.K1302R in SCN4A, p.L208P in ATP2A1 and c.280-1G>C in CASQ1 genes. This study demonstrated the utility of targeted next generation sequencing approach in molecular diagnosis of skeletal muscle channelopathies and the importance of the collaboration between clinicians and molecular geneticists and additional methods for unclear variants to make a conclusive diagnosis.
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Affiliation(s)
- Raffaella Brugnoni
- Neurology IV Unit, Neuroimmunology and Neuromuscular Diseases, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy.
| | - Lorenzo Maggi
- Neurology IV Unit, Neuroimmunology and Neuromuscular Diseases, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Eleonora Canioni
- Neurology IV Unit, Neuroimmunology and Neuromuscular Diseases, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Federico Verde
- Department of Neurology-Stroke Unit and Laboratory of Neuroscience, IRCCS Istituto Auxologico Italiano, Milan, Italy; Department of Pathophysiology and Transplantation, "Dino Ferrari" Center, "Aldo Ravelli" Center for Neurotechnology and Experimental Brain Therapeutics, Università degli Studi di Milano, Milan, Italy
| | - Annamaria Gallone
- Neurology IV Unit, Neuroimmunology and Neuromuscular Diseases, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Alessandra Ariatti
- Department of Neurosciences, Azienda Ospedaliero-Universitaria di Modena, Ospedale Civile di Baggiovara, Modena, Italy
| | - Massimiliano Filosto
- Center for Neuromuscular Diseases, Unit of Neurology, ASST Spedali Civili and University of Brescia, Brescia, Italy
| | | | | | - Marcello Esposito
- Department of Neurosciences, Reproductive, and Odontostomatological Sciences, University Federico II, Naples, Italy
| | - Lucia Ruggiero
- Department of Neurosciences, Reproductive, and Odontostomatological Sciences, University Federico II, Naples, Italy
| | - Paola Tonin
- Neurological Clinic, University of Verona, Verona, Italy
| | - Pietro Riguzzi
- Department of Neurosciences, University of Padova, Padova, Italy
| | - Elena Pegoraro
- Department of Neurosciences, University of Padova, Padova, Italy
| | - Francesca Torri
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Giulia Ricci
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Gabriele Siciliano
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Vincenzo Silani
- Department of Neurology-Stroke Unit and Laboratory of Neuroscience, IRCCS Istituto Auxologico Italiano, Milan, Italy; Department of Pathophysiology and Transplantation, "Dino Ferrari" Center, "Aldo Ravelli" Center for Neurotechnology and Experimental Brain Therapeutics, Università degli Studi di Milano, Milan, Italy
| | - Luciano Merlini
- DIBINEM-Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Silvia De Pasqua
- Dipartimento di Scienze Biomediche e Neuromotorie, Università di Bologna, Bologna, Italy
| | - Rocco Liguori
- Dipartimento di Scienze Biomediche e Neuromotorie, Università di Bologna, Bologna, Italy
| | - Antonella Pini
- Neuromuscular Pediatric Unit, IRRCS Istituto delle Scienze Neurologiche di Bologna
| | - Caterina Mariotti
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Isabella Moroni
- Department of Pediatric Neuroscience, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Paola Imbrici
- Department of Pharmacy-Drug Sciences, University of Bari "Aldo Moro", Bari, Italy
| | - Jean-Francois Desaphy
- Department of Biomedical Sciences and Human Oncology, School of Medicine, University of Bari "Aldo Moro", Bari, Italy
| | - Renato Mantegazza
- Neurology IV Unit, Neuroimmunology and Neuromuscular Diseases, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Pia Bernasconi
- Neurology IV Unit, Neuroimmunology and Neuromuscular Diseases, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
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Wei Z, Huaxing M, Xiaomei W, Juan W, Xueli C, Jing Z, Junhong G. Identification of two novel compound heterozygous CLCN1 mutations associated with autosomal recessive myotonia congenita. Neurol Res 2019; 41:1069-1074. [PMID: 31566103 DOI: 10.1080/01616412.2019.1672392] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Objectives: Myotonia congenita (MC) is a rare genetic muscular disorder caused by CLCN1 mutations, which codes for skeletal muscle chloride channel CLC1. MC is characterized by impaired muscle relaxation after contraction resulting in muscle stiffness. This study aimed to identify the genetic etiology of a Chinese family affected with recessive MC. Methods: Whole exome sequencing was performed to identify the disease-associated variants. The candidate causal genes discovered by WES were then confirmed by Sanger sequencing and co-segregation analyses were also conducted. Results: Two novel compound heterozygous mutations in CLCN1 gene, p.D94Y (paternal allele) and p.Y206* (maternal allele), were successfully identified as the pathogenic mutations by whole-exome sequencing (WES). The mutations were confirmed with Sanger sequencing in the family members and cosegregated with the MC phenotype. The two mutations have not been reported in the HGMD, dbSNP, 1000 Genomes project, ClinVar database, ExAC, and gnomAD previously. Mutation p.D94Y is predicted to be deleterious by using in silico tools and p.Y206* is a nonsense mutation, causing protein synthesis termination. Conclusions: Molecular genetics analysis offers an accurate method for diagnosing MC. Our results expand the mutational spectrum of recessive MC.
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Affiliation(s)
- Zhang Wei
- Department of Neurology, First Hospital, Shanxi Medical University , Taiyuan , China
| | - Meng Huaxing
- Department of Neurology, First Hospital, Shanxi Medical University , Taiyuan , China
| | - Wang Xiaomei
- Department of Geological Engineering, Shanxi Institute of Enegy , Taiyuan , China
| | - Wang Juan
- Department of Neurology, First Hospital, Shanxi Medical University , Taiyuan , China
| | - Chang Xueli
- Department of Neurology, First Hospital, Shanxi Medical University , Taiyuan , China
| | - Zhang Jing
- Department of Neurology, First Hospital, Shanxi Medical University , Taiyuan , China
| | - Guo Junhong
- Department of Neurology, First Hospital, Shanxi Medical University , Taiyuan , China
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Damar IH, Eroz R. Evaluation of Cases with Myotonia Congenita for Cardiovascular Risk. Medeni Med J 2019; 34:374-379. [PMID: 32821464 PMCID: PMC7433722 DOI: 10.5222/mmj.2019.93357] [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: 10/30/2019] [Accepted: 12/06/2019] [Indexed: 11/05/2022] Open
Abstract
Objective Myotonia Congenita (MC) is a hereditary neuromuscular disorder caused by a mutation in chloride voltage-gated channel 1 (CLCN1) gene. The incidence of MC is estimated as 1 in 100.000. The absence of left main coronary artery (LMCA) is a rare coronary anomaly. Here we present a family with four members who have MC variation carrier and cardiovascular risk. Method The demographic features, laboratory findings, anthropometric measurements and cardiological examination of the cases were recorded. In addition, CLCN1 gene was sequenced by NGS (Next Generation Sequencing Method) and possible causes of inherited thrombophilia risk including MTHFR (A1298C), Factor V Leiden (G1691A), Factor II (G20210A), MTHFR (C677T), Factor V Cambridge (G1091C), plasminogen activator inhibitor 1 (PAI-1) 4G/5G, APOE, APOB, ITGB, ACE (ins/del), FVHR2 and FGB gene alterations were evaluated. Results Case 1 had homozygous c.1886T>C (p.Leu629Pro) alteration in CLCN1 gene and also coronary artery disease, myocardial infarction (MI) history, hyperlipidemia, primary hypertension, vertigo, lomber disc herniation and hearing loss. LMCA was not detected in coronary angiography in Case 1. Cases 2, 3 and 4 had heterozygous c.1886T>C (p.Leu629Pro) alteration with normal electrocardiographic and echocardiographic findings. Additionally, all of family members had genetic risk factors for the related gene, which lead to an increased risk of cardiovascular disease. Conclusion Since alteration of chloride channels in cardiomyocytes leads to variable myocardial involvement, cases with MC should be regularly followed for cardiovascular risk. Moreover, the cases with MC and with genetic profile associated with high cardiovascular risk should also be regularly followed up by cardiologists.
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Affiliation(s)
| | - Recep Eroz
- Duzce University Medical Faculty, Department of Medical Genetics, Duzce, Turkey
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SCN4A as modifier gene in patients with myotonic dystrophy type 2. Sci Rep 2018; 8:11058. [PMID: 30038349 PMCID: PMC6056531 DOI: 10.1038/s41598-018-29302-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 07/02/2018] [Indexed: 01/05/2023] Open
Abstract
A patient with an early severe myotonia diagnosed for Myotonic Dystrophy type 2 (DM2) was found bearing the combined effects of DM2 mutation and Nav1.4 S906T substitution. To investigate the mechanism underlying his atypical phenotype,whole-cell patch-clamp in voltage- and current-clamp mode was performed in myoblasts and myotubes obtained from his muscle biopsy. Results characterizing the properties of the sodium current and of the action potentials have been compared to those obtained in muscle cells derived from his mother, also affected by DM2, but without the S906T polymorphism. A faster inactivation kinetics and a +5 mV shift in the availability curve were found in the sodium current recorded in patient’s myoblasts compared to his mother. 27% of his myotubes displayed spontaneous activity. Patient’s myotubes showing a stable resting membrane potential had a lower rheobase current respect to the mother’s while the overshoot and the maximum slope of the depolarizing phase of action potential were higher. These findings suggest that SCN4A polymorphisms may be responsible for a higher excitability of DM2 patients sarcolemma, supporting the severe myotonic phenotype observed. We suggest SCN4A as a modifier factor and that its screening should be performed in DM2 patients with uncommon clinical features.
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