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He Y, Qiu Y, Xiong Y, Shen Y, Jiang K, Yi H, Huang P, Zhu Y, Zhu M, Zhou M, Hong D, Tan D. Clinical and genetic characteristics of myotonia congenita in Chinese population. Channels (Austin) 2024; 18:2349823. [PMID: 38720415 PMCID: PMC11086022 DOI: 10.1080/19336950.2024.2349823] [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: 11/15/2023] [Accepted: 03/22/2024] [Indexed: 05/12/2024] Open
Abstract
Myotonia congenita (MC) is a rare hereditary muscle disease caused by variants in the CLCN1 gene. Currently, the correlation of phenotype-genotype is still uncertain between dominant-type Thomsen (TMC) and recessive-type Becker (BMC). The clinical data and auxiliary examinations of MC patients in our clinic were retrospectively collected. Electromyography was performed in 11 patients and available family members. Whole exome sequencing was conducted in all patients. The clinical and laboratory data of Chinese MC patients reported from June 2004 to December 2022 were reviewed. A total of 11 MC patients were included in the study, with a mean onset age of 12.64 ± 2.73 years. The main symptom was muscle stiffness of limbs. Warm-up phenomenon and percussion myotonia were found in all patients. Electromyogram revealed significant myotonic charges in all patients and two asymptomatic carriers, while muscle MRI and biopsy showed normal or nonspecific changes. Fourteen genetic variants including 6 novel variants were found in CLCN1. Ninety-eight Chinese patients were re-analyzed and re-summarized in this study. There were no significant differences in the demographic data, clinical characteristics, and laboratory findings between 52 TMC and 46 BMC patients. Among the 145 variants in CLCN1, some variants, including the most common variant c.892 G>A, could cause TMC in some families and BMC in others. This study expanded the clinical and genetic spectrum of Chinese patients with MC. It was difficult to distinguish between TMC and BMC only based on the clinical, laboratory, and genetic characteristics.
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Affiliation(s)
- Yuting He
- Department of Neurology, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Yusen Qiu
- Department of Neurology, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China
- Rare Disease Center, the First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Ying Xiong
- Department of Neurology, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China
- Rare Disease Center, the First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Yu Shen
- Department of Neurology, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Kaiyan Jiang
- Department of Neurology, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Hancun Yi
- Department of Neurology, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Pengcheng Huang
- Department of Neurology, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Yu Zhu
- Department of Neurology, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China
- Rare Disease Center, the First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Min Zhu
- Department of Neurology, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China
- Rare Disease Center, the First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Meihong Zhou
- Department of Neurology, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China
- Rare Disease Center, the First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Daojun Hong
- Department of Neurology, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China
- Rare Disease Center, the First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China
- Institute of Neurology, Jiangxi Academy of Clinical Medical Science, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China
- Key Laboratory of Rare Neurological Diseases of Jiangxi Provincial Health Commission, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Dandan Tan
- Department of Neurology, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China
- Rare Disease Center, the First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China
- Institute of Neurology, Jiangxi Academy of Clinical Medical Science, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China
- Key Laboratory of Rare Neurological Diseases of Jiangxi Provincial Health Commission, Jiangxi Medical College, Nanchang University, Nanchang, China
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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. [PMID: 38855810 DOI: 10.1002/mus.28180] [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: 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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Brenes O, Pusch M, Morales F. ClC-1 Chloride Channel: Inputs on the Structure-Function Relationship of Myotonia Congenita-Causing Mutations. Biomedicines 2023; 11:2622. [PMID: 37892996 PMCID: PMC10604815 DOI: 10.3390/biomedicines11102622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 08/11/2023] [Accepted: 08/24/2023] [Indexed: 10/29/2023] Open
Abstract
Myotonia congenita is a hereditary muscle disease mainly characterized by muscle hyperexcitability, which leads to a sustained burst of discharges that correlates with the magnitude and duration of involuntary aftercontractions, muscle stiffness, and hypertrophy. Mutations in the chloride voltage-gated channel 1 (CLCN1) gene that encodes the skeletal muscle chloride channel (ClC-1) are responsible for this disease, which is commonly known as myotonic chloride channelopathy. The biophysical properties of the mutated channel have been explored and analyzed through in vitro approaches, providing important clues to the general function/dysfunction of the wild-type and mutated channels. After an exhaustive search for CLCN1 mutations, we report in this review more than 350 different mutations identified in the literature. We start discussing the physiological role of the ClC-1 channel in skeletal muscle functioning. Then, using the reported functional effects of the naturally occurring mutations, we describe the biophysical and structural characteristics of the ClC-1 channel to update the knowledge of the function of each of the ClC-1 helices, and finally, we attempt to point out some patterns regarding the effects of mutations in the different helices and loops of the protein.
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Affiliation(s)
- Oscar Brenes
- Departamento de Fisiología, Escuela de Medicina, Universidad de Costa Rica, San José 11501-2060, Costa Rica;
- Centro de Investigación en Neurociencias (CIN), Universidad de Costa Rica, San José 11501-2060, Costa Rica
| | - Michael Pusch
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche (CNR), Via De Marini 6, 16149 Genova, Italy
| | - Fernando Morales
- Instituto de Investigaciones en Salud (INISA), Universidad de Costa Rica, San José 11501-2060, Costa Rica
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Suetterlin K, Matthews E, Sud R, McCall S, Fialho D, Burge J, Jayaseelan D, Haworth A, Sweeney MG, Kullmann DM, Schorge S, Hanna MG, Männikkö R. Translating genetic and functional data into clinical practice: a series of 223 families with myotonia. Brain 2022; 145:607-620. [PMID: 34529042 PMCID: PMC9014745 DOI: 10.1093/brain/awab344] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 07/13/2021] [Accepted: 08/05/2021] [Indexed: 11/14/2022] Open
Abstract
High-throughput DNA sequencing is increasingly employed to diagnose single gene neurological and neuromuscular disorders. Large volumes of data present new challenges in data interpretation and its useful translation into clinical and genetic counselling for families. Even when a plausible gene is identified with confidence, interpretation of the clinical significance and inheritance pattern of variants can be challenging. We report our approach to evaluating variants in the skeletal muscle chloride channel ClC-1 identified in 223 probands with myotonia congenita as an example of these challenges. Sequencing of CLCN1, the gene that encodes CLC-1, is central to the diagnosis of myotonia congenita. However, interpreting the pathogenicity and inheritance pattern of novel variants is notoriously difficult as both dominant and recessive mutations are reported throughout the channel sequence, ClC-1 structure-function is poorly understood and significant intra- and interfamilial variability in phenotype is reported. Heterologous expression systems to study functional consequences of CIC-1 variants are widely reported to aid the assessment of pathogenicity and inheritance pattern. However, heterogeneity of reported analyses does not allow for the systematic correlation of available functional and genetic data. We report the systematic evaluation of 95 CIC-1 variants in 223 probands, the largest reported patient cohort, in which we apply standardized functional analyses and correlate this with clinical assessment and inheritance pattern. Such correlation is important to determine whether functional data improves the accuracy of variant interpretation and likely mode of inheritance. Our data provide an evidence-based approach that functional characterization of ClC-1 variants improves clinical interpretation of their pathogenicity and inheritance pattern, and serve as reference for 34 previously unreported and 28 previously uncharacterized CLCN1 variants. In addition, we identify novel pathogenic mechanisms and find that variants that alter voltage dependence of activation cluster in the first half of the transmembrane domains and variants that yield no currents cluster in the second half of the transmembrane domain. None of the variants in the intracellular domains were associated with dominant functional features or dominant inheritance pattern of myotonia congenita. Our data help provide an initial estimate of the anticipated inheritance pattern based on the location of a novel variant and shows that systematic functional characterization can significantly refine the assessment of risk of an associated inheritance pattern and consequently the clinical and genetic counselling.
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Affiliation(s)
- Karen Suetterlin
- MRC International Centre for Genomic Medicine in Neuromuscular Diseases, Department of Neuromuscular Disease, UCL Queen Square Institute of Neurology, London, UK
- AGE Research Group, NIHR Newcastle Biomedical Research Centre, Newcastle-upon-Tyne Hospitals NHS Foundation Trust and Newcastle University, Newcastle-upon-Tyne, UK
| | - Emma Matthews
- MRC International Centre for Genomic Medicine in Neuromuscular Diseases, Department of Neuromuscular Disease, UCL Queen Square Institute of Neurology, London, UK
- Atkinson Morley Neuromuscular Centre, Department of Neurology, St Georges University Hospitals NHS Foundation Trust, London, UK
| | - Richa Sud
- Neurogenetics Unit, UCL Queen Square Institute of Neurology, London, UK
| | - Samuel McCall
- Neurogenetics Unit, UCL Queen Square Institute of Neurology, London, UK
| | - Doreen Fialho
- MRC International Centre for Genomic Medicine in Neuromuscular Diseases, Department of Neuromuscular Disease, UCL Queen Square Institute of Neurology, London, UK
- Department of Clinical Neurophysiology, King’s College Hospital, London, UK
| | - James Burge
- MRC International Centre for Genomic Medicine in Neuromuscular Diseases, Department of Neuromuscular Disease, UCL Queen Square Institute of Neurology, London, UK
- Department of Clinical Neurophysiology, King’s College Hospital, London, UK
| | - Dipa Jayaseelan
- MRC International Centre for Genomic Medicine in Neuromuscular Diseases, Department of Neuromuscular Disease, UCL Queen Square Institute of Neurology, London, UK
| | - Andrea Haworth
- Neurogenetics Unit, UCL Queen Square Institute of Neurology, London, UK
| | - Mary G Sweeney
- Neurogenetics Unit, UCL Queen Square Institute of Neurology, London, UK
| | - Dimitri M Kullmann
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK
| | - Stephanie Schorge
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK
- Department of Pharmacology, UCL School of Pharmacy, London, UK
| | - Michael G Hanna
- MRC International Centre for Genomic Medicine in Neuromuscular Diseases, Department of Neuromuscular Disease, UCL Queen Square Institute of Neurology, London, UK
| | - Roope Männikkö
- MRC International Centre for Genomic Medicine in Neuromuscular Diseases, Department of Neuromuscular Disease, UCL Queen Square Institute of Neurology, London, UK
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Brenes O, Barbieri R, Vásquez M, Vindas-Smith R, Roig J, Romero A, del Valle G, Bermúdez-Guzmán L, Bertelli S, Pusch M, Morales F. Functional and Structural Characterization of ClC-1 and Na v1.4 Channels Resulting from CLCN1 and SCN4A Mutations Identified Alone and Coexisting in Myotonic Patients. Cells 2021; 10:cells10020374. [PMID: 33670307 PMCID: PMC7918176 DOI: 10.3390/cells10020374] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 01/13/2021] [Accepted: 01/13/2021] [Indexed: 11/25/2022] Open
Abstract
Non-dystrophic myotonias have been linked to loss-of-function mutations in the ClC-1 chloride channel or gain-of-function mutations in the Nav1.4 sodium channel. Here, we describe a family with members diagnosed with Thomsen’s disease. One novel mutation (p.W322*) in CLCN1 and one undescribed mutation (p.R1463H) in SCN4A are segregating in this family. The CLCN1-p.W322* was also found in an unrelated family, in compound heterozygosity with the known CLCN1-p.G355R mutation. One reported mutation, SCN4A-p.T1313M, was found in a third family. Both CLCN1 mutations exhibited loss-of-function: CLCN1-p.W322* probably leads to a non-viable truncated protein; for CLCN1-p.G355R, we predict structural damage, triggering important steric clashes. The SCN4A-p.R1463H produced a positive shift in the steady-state inactivation increasing window currents and a faster recovery from inactivation. These gain-of-function effects are probably due to a disruption of interaction R1463-D1356, which destabilizes the voltage sensor domain (VSD) IV and increases the flexibility of the S4-S5 linker. Finally, modelling suggested that the p.T1313M induces a strong decrease in protein flexibility on the III-IV linker. This study demonstrates that CLCN1-p.W322* and SCN4A-p.R1463H mutations can act alone or in combination as inducers of myotonia. Their co-segregation highlights the necessity for carrying out deep genetic analysis to provide accurate genetic counseling and management of patients.
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Affiliation(s)
- Oscar Brenes
- Departamento de Fisiología, Escuela de Medicina, Universidad de Costa Rica, 11501 San José, Costa Rica;
- Centro de Investigación en Neurociencias (CIN), Universidad de Costa Rica, 11501 San José, Costa Rica
| | | | - Melissa Vásquez
- Instituto de Investigaciones en Salud (INISA), Universidad de Costa Rica, 11501 San José, Costa Rica; (M.V.); (R.V.-S.); (J.R.)
| | - Rebeca Vindas-Smith
- Instituto de Investigaciones en Salud (INISA), Universidad de Costa Rica, 11501 San José, Costa Rica; (M.V.); (R.V.-S.); (J.R.)
| | - Jeffrey Roig
- Instituto de Investigaciones en Salud (INISA), Universidad de Costa Rica, 11501 San José, Costa Rica; (M.V.); (R.V.-S.); (J.R.)
| | - Adarli Romero
- Escuela de Biología, Universidad de Costa Rica, 11501 San José, Costa Rica;
| | - Gerardo del Valle
- Laboratorio de Neurofisiología (Neurolab), 11801 San José, Costa Rica;
| | - Luis Bermúdez-Guzmán
- Sección de Genética y Biotecnología, Escuela de Biología, Universidad de Costa Rica, 11501 San José, Costa Rica;
| | - Sara Bertelli
- Istituto di Biofisica, CNR, 16149 Genova, Italy; (R.B.); (S.B.)
- Scuola Internazionale Superiore di Studi Avanzati (SISSA), 34136 Trieste, Italy
| | - Michael Pusch
- Istituto di Biofisica, CNR, 16149 Genova, Italy; (R.B.); (S.B.)
- Correspondence: (M.P.); (F.M.); Tel.: +39-0106475-553/522 (M.P.); +506-2511-2124 (F.M.)
| | - Fernando Morales
- Instituto de Investigaciones en Salud (INISA), Universidad de Costa Rica, 11501 San José, Costa Rica; (M.V.); (R.V.-S.); (J.R.)
- Correspondence: (M.P.); (F.M.); Tel.: +39-0106475-553/522 (M.P.); +506-2511-2124 (F.M.)
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Exner CRT, Willsey HR. Xenopus leads the way: Frogs as a pioneering model to understand the human brain. Genesis 2021; 59:e23405. [PMID: 33369095 PMCID: PMC8130472 DOI: 10.1002/dvg.23405] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 12/12/2020] [Accepted: 12/14/2020] [Indexed: 12/20/2022]
Abstract
From its long history in the field of embryology to its recent advances in genetics, Xenopus has been an indispensable model for understanding the human brain. Foundational studies that gave us our first insights into major embryonic patterning events serve as a crucial backdrop for newer avenues of investigation into organogenesis and organ function. The vast array of tools available in Xenopus laevis and Xenopus tropicalis allows interrogation of developmental phenomena at all levels, from the molecular to the behavioral, and the application of CRISPR technology has enabled the investigation of human disorder risk genes in a higher-throughput manner. As the only major tetrapod model in which all developmental stages are easily manipulated and observed, frogs provide the unique opportunity to study organ development from the earliest stages. All of these features make Xenopus a premier model for studying the development of the brain, a notoriously complex process that demands an understanding of all stages from fertilization to organogenesis and beyond. Importantly, core processes of brain development are conserved between Xenopus and human, underlining the advantages of this model. This review begins by summarizing discoveries made in amphibians that form the cornerstones of vertebrate neurodevelopmental biology and goes on to discuss recent advances that have catapulted our understanding of brain development in Xenopus and in relation to human development and disease. As we engage in a new era of patient-driven gene discovery, Xenopus offers exceptional potential to uncover conserved biology underlying human brain disorders and move towards rational drug design.
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Affiliation(s)
- Cameron R T Exner
- Department of Psychiatry and Behavioral Sciences, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, California, 94143, USA
| | - Helen Rankin Willsey
- Department of Psychiatry and Behavioral Sciences, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, California, 94143, USA
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7
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Jehasse K, Jacquerie K, de Froidmont A, Lemoine C, Grisar T, Stouffs K, Lakaye B, Seutin V. Functional analysis of the F337C mutation in the CLCN1 gene associated with dominant myotonia congenita reveals an alteration of the macroscopic conductance and voltage dependence. Mol Genet Genomic Med 2021; 9:e1588. [PMID: 33507632 PMCID: PMC8077071 DOI: 10.1002/mgg3.1588] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 11/27/2020] [Accepted: 12/15/2020] [Indexed: 01/14/2023] Open
Abstract
Background Myotonia congenita (MC) is a common channelopathy affecting skeletal muscle and which is due to pathogenic variants within the CLCN1 gene. Various alterations in the function of the channel have been reported and we here illustrate a novel one. Methods A patient presenting the symptoms of myotonia congenita was shown to bear a new heterozygous missense variant in exon 9 of the CLCN1 gene (c.1010 T > G, p.(Phe337Cys)). Confocal imaging and patch clamp recordings of transiently transfected HEK293 cells were used to functionally analyze the effect of this variant on channel properties. Results Confocal imaging showed that the F337C mutant incorporated as well as the WT channel into the plasma membrane. However, in patch clamp, we observed a smaller conductance for F337C at −80 mV. We also found a marked reduction of the fast gating component in the mutant channels, as well as an overall reduced voltage dependence. Conclusion To our knowledge, this is the first report of a mixed alteration in the biophysical properties of hClC‐1 consisting of a reduced conductance at resting potential and an almost abolished voltage dependence.
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Affiliation(s)
- Kevin Jehasse
- Laboratory of NeurophysiologyGIGA InstituteLiegeBelgium
| | - Kathleen Jacquerie
- Department of Electrical Engineering and Computer ScienceLiège UniversityLiègeBelgium
| | | | | | - Thierry Grisar
- Laboratory of Molecular Regulation of NeurogenesisGIGA InstituteLiègeBelgium
| | - Katrien Stouffs
- Neurogenetics Research GroupVrije Universiteit Brussel (VUBUniversitair Ziekenhuis Brussel (UZ Brussel), Reproduction and GeneticsBrusselsBelgium
| | - Bernard Lakaye
- Laboratory of Molecular Regulation of NeurogenesisGIGA InstituteLiègeBelgium
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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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9
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Zaganas I, Mastorodemos V, Spilioti M, Mathioudakis L, Latsoudis H, Michaelidou K, Kotzamani D, Notas K, Dimitrakopoulos K, Skoula I, Ioannidis S, Klothaki E, Erimaki S, Stavropoulos G, Vassilikos V, Amoiridis G, Efthimiadis G, Evangeliou A, Mitsias P. Genetic cause of heterogeneous inherited myopathies in a cohort of Greek patients. Mol Genet Metab Rep 2020; 25:100682. [PMID: 33304817 PMCID: PMC7711282 DOI: 10.1016/j.ymgmr.2020.100682] [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] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Revised: 11/13/2020] [Accepted: 11/13/2020] [Indexed: 02/07/2023] Open
Abstract
Inherited muscle disorders are caused by pathogenic changes in numerous genes. Herein, we aimed to investigate the etiology of muscle disease in 24 consecutive Greek patients with myopathy suspected to be genetic in origin, based on clinical presentation and laboratory and electrophysiological findings and absence of known acquired causes of myopathy. Of these, 16 patients (8 females, median 24 years-old, range 7 to 67 years-old) were diagnosed by Whole Exome Sequencing as suffering from a specific type of inherited muscle disorder. Specifically, we have identified causative variants in 6 limb-girdle muscular dystrophy genes (6 patients; ANO5, CAPN3, DYSF, ISPD, LAMA2, SGCA), 3 metabolic myopathy genes (4 patients; CPT2, ETFDH, GAA), 1 congenital myotonia gene (1 patient; CLCN1), 1 mitochondrial myopathy gene (1 patient; MT-TE) and 3 other myopathy-associated genes (4 patients; CAV3, LMNA, MYOT). In 6 additional family members affected by myopathy, we reached genetic diagnosis following identification of a causative variant in an index patient. In our patients, genetic diagnosis ended a lengthy diagnostic process and, in the case of Multiple acyl-CoA dehydrogenase deficiency and Pompe's disease, it enabled specific treatment to be initiated. These results further expand the genotypic and phenotypic spectrum of inherited myopathies.
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Affiliation(s)
- Ioannis Zaganas
- Neurogenetics Laboratory, Medical School, University of Crete, Heraklion, Crete, Greece.,Neurology Department, University Hospital of Crete, Heraklion, Crete, Greece
| | | | - Martha Spilioti
- AHEPA General Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Lambros Mathioudakis
- Neurogenetics Laboratory, Medical School, University of Crete, Heraklion, Crete, Greece
| | - Helen Latsoudis
- Neurogenetics Laboratory, Medical School, University of Crete, Heraklion, Crete, Greece
| | - Kleita Michaelidou
- Neurogenetics Laboratory, Medical School, University of Crete, Heraklion, Crete, Greece
| | - Dimitra Kotzamani
- Neurogenetics Laboratory, Medical School, University of Crete, Heraklion, Crete, Greece
| | - Konstantinos Notas
- AHEPA General Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | | | - Irene Skoula
- Neurogenetics Laboratory, Medical School, University of Crete, Heraklion, Crete, Greece
| | - Stefanos Ioannidis
- Neurology Department, University Hospital of Crete, Heraklion, Crete, Greece
| | - Eirini Klothaki
- Neurology Department, University Hospital of Crete, Heraklion, Crete, Greece
| | - Sophia Erimaki
- Neurophysiology Unit, University Hospital of Crete, Heraklion, Crete, Greece
| | - Georgios Stavropoulos
- Hippokratio General Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Vassilios Vassilikos
- Hippokratio General Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Georgios Amoiridis
- Neurophysiology Unit, University Hospital of Crete, Heraklion, Crete, Greece
| | - Georgios Efthimiadis
- AHEPA General Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Athanasios Evangeliou
- Papageorgiou General Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Panayiotis Mitsias
- Neurology Department, University Hospital of Crete, Heraklion, Crete, Greece.,Neurophysiology Unit, University Hospital of Crete, Heraklion, Crete, Greece.,Department of Neurology, Henry Ford Hospital/Wayne State University, Detroit, Michigan, USA
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10
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Stunnenberg BC, LoRusso S, Arnold WD, Barohn RJ, Cannon SC, Fontaine B, Griggs RC, Hanna MG, Matthews E, Meola G, Sansone VA, Trivedi JR, van Engelen BG, Vicart S, Statland JM. Guidelines on clinical presentation and management of nondystrophic myotonias. Muscle Nerve 2020; 62:430-444. [PMID: 32270509 PMCID: PMC8117169 DOI: 10.1002/mus.26887] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 04/01/2020] [Accepted: 04/04/2020] [Indexed: 12/26/2022]
Abstract
The nondystrophic myotonias are rare muscle hyperexcitability disorders caused by gain-of-function mutations in the SCN4A gene or loss-of-function mutations in the CLCN1 gene. Clinically, they are characterized by myotonia, defined as delayed muscle relaxation after voluntary contraction, which leads to symptoms of muscle stiffness, pain, fatigue, and weakness. Diagnosis is based on history and examination findings, the presence of electrical myotonia on electromyography, and genetic confirmation. In the absence of genetic confirmation, the diagnosis is supported by detailed electrophysiological testing, exclusion of other related disorders, and analysis of a variant of uncertain significance if present. Symptomatic treatment with a sodium channel blocker, such as mexiletine, is usually the first step in management, as well as educating patients about potential anesthetic complications.
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Affiliation(s)
- Bas C. Stunnenberg
- Department of Neurology, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Samantha LoRusso
- Department of Neurology, Ohio State University Wexner Medical Center, Columbus, Ohio
| | - W. David Arnold
- Department of Neurology, Ohio State University Wexner Medical Center, Columbus, Ohio
| | - Richard J. Barohn
- Department of Neurology, University of Kansas Medical Center, Kansas City, Kansas
| | - Stephen C. Cannon
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California
| | - Bertrand Fontaine
- Assistance Publique-Hôpitaix de Paris, Sorbonne Université, INSERM, Service of Neuro-Myology and UMR 974, Institute of Myology, University Hospital Pitié-Salpêtrière, Paris, France
| | - Robert C. Griggs
- Department of Neurology, University of Rochester, Rochester, New York
| | - Michael G. Hanna
- MRC Centre for Neuromuscular Diseases, Department of Neuromuscular diseases, UCL Queen Square Institute of Neurology, United Kingdom
| | - Emma Matthews
- MRC Centre for Neuromuscular Diseases, Department of Neuromuscular diseases, UCL Queen Square Institute of Neurology, United Kingdom
| | - Giovanni Meola
- Department of Neurorehabilitation Sciences, Casa Cura Policlinico, Milan, Italy
- Department of Biomedical Sciences for Health, University of Milan, Milan, Italy
| | - Valeria A. Sansone
- Department of Biomedical Sciences for Health, University of Milan, Milan, Italy
- Neurorehabilitation Unit, University of Milan, NEuroMuscular Omnicentre (NEMO), Fondazione Serena Onlus, Milan, Italy
| | - Jaya R. Trivedi
- Department of Neurology and Neurotherapeutics, UT Southwestern Medical Center, Dallas, Texas
| | | | - Savine Vicart
- Assistance Publique-Hôpitaix de Paris, Sorbonne Université, INSERM, Service of Neuro-Myology and UMR 974, Institute of Myology, University Hospital Pitié-Salpêtrière, Paris, France
| | - Jeffrey M. Statland
- Department of Neurology, University of Kansas Medical Center, Kansas City, Kansas
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11
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Altamura C, Ivanova EA, Imbrici P, Conte E, Camerino GM, Dadali EL, Polyakov AV, Kurbatov SA, Girolamo F, Carratù MR, Desaphy JF. Pathomechanisms of a CLCN1 Mutation Found in a Russian Family Suffering From Becker's Myotonia. Front Neurol 2020; 11:1019. [PMID: 33013670 PMCID: PMC7500137 DOI: 10.3389/fneur.2020.01019] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 08/04/2020] [Indexed: 11/13/2022] Open
Abstract
Objective: Myotonia congenita (MC) is a rare muscle disease characterized by sarcolemma over-excitability inducing skeletal muscle stiffness. It can be inherited either as an autosomal dominant (Thomsen's disease) or an autosomal recessive (Becker's disease) trait. Both types are caused by loss-of-function mutations in the CLCN1 gene, encoding for ClC-1 chloride channel. We found a ClC-1 mutation, p.G411C, identified in Russian patients who suffered from a severe form of Becker's disease. The purpose of this study was to provide a solid correlation between G411C dysfunction and clinical symptoms in the affected patient. Methods: We provide clinical and genetic information of the proband kindred. Functional studies include patch-clamp electrophysiology, biotinylation assay, western blot analysis, and confocal imaging of G411C and wild-type ClC-1 channels expressed in HEK293T cells. Results: The G411C mutation dramatically abolished chloride currents in transfected HEK cells. Biochemical experiments revealed that the majority of G411C mutant channels did not reach the plasma membrane but remained trapped in the cytoplasm. Treatment with the proteasome inhibitor MG132 reduced the degradation rate of G411C mutant channels, leading to their expression at the plasma membrane. However, despite an increase in cell surface expression, no significant chloride current was recorded in the G411C-transfected cell treated with MG132, suggesting that this mutation produces non-functional ClC-1 chloride channels. Conclusion: These results suggest that the molecular pathophysiology of G411C is linked to a reduced plasma membrane expression and biophysical dysfunction of mutant channels, likely due to a misfolding defect. Chloride current abolition confirms that the mutation is responsible for the clinical phenotype.
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Affiliation(s)
- Concetta Altamura
- Section of Pharmacology, Department of Biomedical Sciences and Human Oncology, School of Medicine, University of Bari Aldo Moro, Bari, Italy
| | - Evgeniya A Ivanova
- N.P. Bochkov's Research Centre for Medical Genetics, Federal State Budgetary Scientific Institution, Moscow, Russia
| | - Paola Imbrici
- Section of Pharmacology, Department of Pharmacy-Drug Sciences, University of Bari Aldo Moro, Bari, Italy
| | - Elena Conte
- Section of Pharmacology, Department of Pharmacy-Drug Sciences, University of Bari Aldo Moro, Bari, Italy
| | - Giulia Maria Camerino
- Section of Pharmacology, Department of Pharmacy-Drug Sciences, University of Bari Aldo Moro, Bari, Italy
| | - Elena L Dadali
- N.P. Bochkov's Research Centre for Medical Genetics, Federal State Budgetary Scientific Institution, Moscow, Russia
| | - Alexander V Polyakov
- N.P. Bochkov's Research Centre for Medical Genetics, Federal State Budgetary Scientific Institution, Moscow, Russia
| | | | - Francesco Girolamo
- Unit of Human Anatomy and Histology, Department of Basic Medical Sciences, Neuroscience, and Sense Organs, School of Medicine, University of Bari Aldo Moro, Bari, Italy
| | - Maria Rosaria Carratù
- Section of Pharmacology, Department of Biomedical Sciences and Human Oncology, School of Medicine, University of Bari Aldo Moro, Bari, Italy
| | - Jean-François Desaphy
- Section of Pharmacology, Department of Biomedical Sciences and Human Oncology, School of Medicine, University of Bari Aldo Moro, Bari, Italy
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12
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Altamura C, Desaphy JF, Conte D, De Luca A, Imbrici P. Skeletal muscle ClC-1 chloride channels in health and diseases. Pflugers Arch 2020; 472:961-975. [PMID: 32361781 DOI: 10.1007/s00424-020-02376-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 03/18/2020] [Accepted: 03/31/2020] [Indexed: 12/14/2022]
Abstract
In 1970, the study of the pathomechanisms underlying myotonia in muscle fibers isolated from myotonic goats highlighted the importance of chloride conductance for skeletal muscle function; 20 years later, the human ClC-1 chloride channel has been cloned; last year, the crystal structure of human protein has been solved. Over the years, the efforts of many researchers led to significant advances in acknowledging the role of ClC-1 in skeletal muscle physiology and the mechanisms through which ClC-1 dysfunctions lead to impaired muscle function. The wide spectrum of pathophysiological conditions associated with modification of ClC-1 activity, either as the primary cause, such as in myotonia congenita, or as a secondary adaptive mechanism in other neuromuscular diseases, supports the idea that ClC-1 is relevant to preserve not only for skeletal muscle excitability, but also for skeletal muscle adaptation to physiological or harmful events. Improving this understanding could open promising avenues toward the development of selective and safe drugs targeting ClC-1, with the aim to restore normal muscle function. This review summarizes the most relevant research on ClC-1 channel physiology, associated diseases, and pharmacology.
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Affiliation(s)
- Concetta Altamura
- Department of Biomedical Sciences and Human Oncology, School of Medicine, 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
| | - Diana Conte
- Department of Pharmacy-Drug Sciences, University of Bari "Aldo Moro", Bari, Italy
| | - Annamaria De Luca
- Department of Pharmacy-Drug Sciences, University of Bari "Aldo Moro", Bari, Italy
| | - Paola Imbrici
- Department of Pharmacy-Drug Sciences, University of Bari "Aldo Moro", Bari, Italy.
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13
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Jeng CJ, Fu SJ, You CY, Peng YJ, Hsiao CT, Chen TY, Tang CY. Defective Gating and Proteostasis of Human ClC-1 Chloride Channel: Molecular Pathophysiology of Myotonia Congenita. Front Neurol 2020; 11:76. [PMID: 32117034 PMCID: PMC7026490 DOI: 10.3389/fneur.2020.00076] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 01/22/2020] [Indexed: 01/17/2023] Open
Abstract
The voltage-dependent ClC-1 chloride channel, whose open probability increases with membrane potential depolarization, belongs to the superfamily of CLC channels/transporters. ClC-1 is almost exclusively expressed in skeletal muscles and is essential for stabilizing the excitability of muscle membranes. Elucidation of the molecular structures of human ClC-1 and several CLC homologs provides important insight to the gating and ion permeation mechanisms of this chloride channel. Mutations in the human CLCN1 gene, which encodes the ClC-1 channel, are associated with a hereditary skeletal muscle disease, myotonia congenita. Most disease-causing CLCN1 mutations lead to loss-of-function phenotypes in the ClC-1 channel and thus increase membrane excitability in skeletal muscles, consequently manifesting as delayed relaxations following voluntary muscle contractions in myotonic subjects. The inheritance pattern of myotonia congenita can be autosomal dominant (Thomsen type) or recessive (Becker type). To date over 200 myotonia-associated ClC-1 mutations have been identified, which are scattered throughout the entire protein sequence. The dominant inheritance pattern of some myotonia mutations may be explained by a dominant-negative effect on ClC-1 channel gating. For many other myotonia mutations, however, no clear relationship can be established between the inheritance pattern and the location of the mutation in the ClC-1 protein. Emerging evidence indicates that the effects of some mutations may entail impaired ClC-1 protein homeostasis (proteostasis). Proteostasis of membrane proteins comprises of biogenesis at the endoplasmic reticulum (ER), trafficking to the surface membrane, and protein turn-over at the plasma membrane. Maintenance of proteostasis requires the coordination of a wide variety of different molecular chaperones and protein quality control factors. A number of regulatory molecules have recently been shown to contribute to post-translational modifications of ClC-1 and play critical roles in the ER quality control, membrane trafficking, and peripheral quality control of this chloride channel. Further illumination of the mechanisms of ClC-1 proteostasis network will enhance our understanding of the molecular pathophysiology of myotonia congenita, and may also bring to light novel therapeutic targets for skeletal muscle dysfunction caused by myotonia and other pathological conditions.
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Affiliation(s)
- Chung-Jiuan Jeng
- Institute of Anatomy and Cell Biology, School of Medicine, National Yang-Ming University, Taipei, Taiwan.,Brain Research Center, National Yang-Ming University, Taipei, Taiwan
| | - Ssu-Ju Fu
- Institute of Anatomy and Cell Biology, School of Medicine, National Yang-Ming University, Taipei, Taiwan.,Department of Physiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chia-Ying You
- Department of Physiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Yi-Jheng Peng
- Department of Physiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Cheng-Tsung Hsiao
- Department of Physiology, College of Medicine, National Taiwan University, Taipei, Taiwan.,Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Tsung-Yu Chen
- Center for Neuroscience, University of California, Davis, Davis, CA, United States
| | - Chih-Yung Tang
- Department of Physiology, College of Medicine, National Taiwan University, Taipei, Taiwan.,College of Medicine, Graduate Institute of Brain and Mind Sciences, National Taiwan University, Taipei, Taiwan
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14
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Morales F, Pusch M. An Up-to-Date Overview of the Complexity of Genotype-Phenotype Relationships in Myotonic Channelopathies. Front Neurol 2020; 10:1404. [PMID: 32010054 PMCID: PMC6978732 DOI: 10.3389/fneur.2019.01404] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 12/23/2019] [Indexed: 12/11/2022] Open
Abstract
Myotonic disorders are inherited neuromuscular diseases divided into dystrophic myotonias and non-dystrophic myotonias (NDM). The latter is a group of dominant or recessive diseases caused by mutations in genes encoding ion channels that participate in the generation and control of the skeletal muscle action potential. Their altered function causes hyperexcitability of the muscle membrane, thereby triggering myotonia, the main sign in NDM. Mutations in the genes encoding voltage-gated Cl− and Na+ channels (respectively, CLCN1 and SCN4A) produce a wide spectrum of phenotypes, which differ in age of onset, affected muscles, severity of myotonia, degree of hypertrophy, and muscle weakness, disease progression, among others. More than 200 CLCN1 and 65 SCN4A mutations have been identified and described, but just about half of them have been functionally characterized, an approach that is likely extremely helpful to contribute to improving the so-far rather poor clinical correlations present in NDM. The observed poor correlations may be due to: (1) the wide spectrum of symptoms and overlapping phenotypes present in both groups (Cl− and Na+ myotonic channelopathies) and (2) both genes present high genotypic variability. On the one hand, several mutations cause a unique and reproducible phenotype in most patients. On the other hand, some mutations can have different inheritance pattern and clinical phenotypes in different families. Conversely, different mutations can be translated into very similar phenotypes. For these reasons, the genotype-phenotype relationships in myotonic channelopathies are considered complex. Although the molecular bases for the clinical variability present in myotonic channelopathies remain obscure, several hypotheses have been put forward to explain the variability, which include: (a) differential allelic expression; (b) trans-acting genetic modifiers; (c) epigenetic, hormonal, or environmental factors; and (d) dominance with low penetrance. Improvements in clinical tests, the recognition of the different phenotypes that result from particular mutations and the understanding of how a mutation affects the structure and function of the ion channel, together with genetic screening, is expected to improve clinical correlation in NDMs.
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Affiliation(s)
- Fernando Morales
- Instituto de Investigaciones en Salud, Universidad de Costa, San José, Costa Rica
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15
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Barbieri R, Bertelli S, Pusch M, Gavazzo P. Late sodium current blocker GS967 inhibits persistent currents induced by familial hemiplegic migraine type 3 mutations of the SCN1A gene. J Headache Pain 2019; 20:107. [PMID: 31730442 PMCID: PMC6858687 DOI: 10.1186/s10194-019-1056-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 10/29/2019] [Indexed: 01/31/2023] Open
Abstract
Background Familial hemiplegic migraine (FHM) is a group of genetic migraine, associated with hemiparesis and aura. Three causative different genes have been identified, all of which are involved in membrane ion transport. Among these, SCN1A encodes the voltage-gated Na+ channel Nav1.1, and FHM caused by mutations of SCN1A is named FHM3. For 7 of the 12 known FHM3-causing SCNA1 mutations functional consequences have been investigated, and even if gain of function effect seems to be a predominant phenotype, for several mutations conflicting results have been obtained and the available data do not reveal a univocal FHM3 pathomechanism. Methods To obtain a more complete picture, here, we characterized by patch clamp approach the remaining 5 mutations (Q1489H, I1498M, F1499 L, M1500 V, F1661 L) in heterologous expression systems. Results With the exception of I1498M, all mutants exhibited the same current density as WT and exhibited a shift of the steady state inactivation to more positive voltages, an accelerated recovery from inactivation, and an increase of the persistent current, revealing that most FHM3 mutations induce a gain of function. We also determined the effect of GS967, a late Na+ current blocker, on the above mentioned mutants as well as on previously characterized ones (L1649Q, L1670 W, F1774S). GS967 inhibited persistent currents of all SCNA1 FMH3-related mutants and dramatically slowed the recovery from fast inactivation of WT and mutants, consistent with the hypothesis that GS967 specifically binds to and thereby stabilizes the fast inactivated state. Simulation of neuronal firing showed that enhanced persistent currents cause an increase of ionic fluxes during action potential repolarization and consequent accumulation of K+ and/or exhaustion of neuronal energy resources. In silico application of GS967 largely reduced net ionic currents in neurons without impairing excitability. Conclusion In conclusion, late Na+ current blockers appear a promising specific pharmacological treatment of FHM3.
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Affiliation(s)
- R Barbieri
- Biophysics Institute, National Research Council, Via De Marini 6, Genoa, Italy
| | - S Bertelli
- Biophysics Institute, National Research Council, Via De Marini 6, Genoa, Italy.,International School of Advanced Studies (SISSA), Via Bonomea, 265, Trieste, Italy
| | - M Pusch
- Biophysics Institute, National Research Council, Via De Marini 6, Genoa, Italy
| | - P Gavazzo
- Biophysics Institute, National Research Council, Via De Marini 6, Genoa, Italy.
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16
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Nenni MJ, Fisher ME, James-Zorn C, Pells TJ, Ponferrada V, Chu S, Fortriede JD, Burns KA, Wang Y, Lotay VS, Wang DZ, Segerdell E, Chaturvedi P, Karimi K, Vize PD, Zorn AM. Xenbase: Facilitating the Use of Xenopus to Model Human Disease. Front Physiol 2019; 10:154. [PMID: 30863320 PMCID: PMC6399412 DOI: 10.3389/fphys.2019.00154] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 02/08/2019] [Indexed: 01/02/2023] Open
Abstract
At a fundamental level most genes, signaling pathways, biological functions and organ systems are highly conserved between man and all vertebrate species. Leveraging this conservation, researchers are increasingly using the experimental advantages of the amphibian Xenopus to model human disease. The online Xenopus resource, Xenbase, enables human disease modeling by curating the Xenopus literature published in PubMed and integrating these Xenopus data with orthologous human genes, anatomy, and more recently with links to the Online Mendelian Inheritance in Man resource (OMIM) and the Human Disease Ontology (DO). Here we review how Xenbase supports disease modeling and report on a meta-analysis of the published Xenopus research providing an overview of the different types of diseases being modeled in Xenopus and the variety of experimental approaches being used. Text mining of over 50,000 Xenopus research articles imported into Xenbase from PubMed identified approximately 1,000 putative disease- modeling articles. These articles were manually assessed and annotated with disease ontologies, which were then used to classify papers based on disease type. We found that Xenopus is being used to study a diverse array of disease with three main experimental approaches: cell-free egg extracts to study fundamental aspects of cellular and molecular biology, oocytes to study ion transport and channel physiology and embryo experiments focused on congenital diseases. We integrated these data into Xenbase Disease Pages to allow easy navigation to disease information on external databases. Results of this analysis will equip Xenopus researchers with a suite of experimental approaches available to model or dissect a pathological process. Ideally clinicians and basic researchers will use this information to foster collaborations necessary to interrogate the development and treatment of human diseases.
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Affiliation(s)
- Mardi J Nenni
- Division of Developmental Biology, Cincinnati Children's Hospital, Cincinnati, OH, United States
| | - Malcolm E Fisher
- Division of Developmental Biology, Cincinnati Children's Hospital, Cincinnati, OH, United States
| | - Christina James-Zorn
- Division of Developmental Biology, Cincinnati Children's Hospital, Cincinnati, OH, United States
| | - Troy J Pells
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Virgilio Ponferrada
- Division of Developmental Biology, Cincinnati Children's Hospital, Cincinnati, OH, United States
| | - Stanley Chu
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Joshua D Fortriede
- Division of Developmental Biology, Cincinnati Children's Hospital, Cincinnati, OH, United States
| | - Kevin A Burns
- Division of Developmental Biology, Cincinnati Children's Hospital, Cincinnati, OH, United States
| | - Ying Wang
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Vaneet S Lotay
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Dong Zhou Wang
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Erik Segerdell
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR, United States
| | - Praneet Chaturvedi
- Division of Developmental Biology, Cincinnati Children's Hospital, Cincinnati, OH, United States
| | - Kamran Karimi
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Peter D Vize
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Aaron M Zorn
- Division of Developmental Biology, Cincinnati Children's Hospital, Cincinnati, OH, United States
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Altamura C, Lucchiari S, Sahbani D, Ulzi G, Comi GP, D'Ambrosio P, Petillo R, Politano L, Vercelli L, Mongini T, Dotti MT, Cardani R, Meola G, Lo Monaco M, Matthews E, Hanna MG, Carratù MR, Conte D, Imbrici P, Desaphy JF. The analysis of myotonia congenita mutations discloses functional clusters of amino acids within the CBS2 domain and the C-terminal peptide of the ClC-1 channel. Hum Mutat 2018; 39:1273-1283. [PMID: 29935101 DOI: 10.1002/humu.23581] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 06/19/2018] [Accepted: 06/20/2018] [Indexed: 11/10/2022]
Abstract
Myotonia congenita (MC) is a skeletal-muscle hyperexcitability disorder caused by loss-of-function mutations in the ClC-1 chloride channel. Mutations are scattered over the entire sequence of the channel protein, with more than 30 mutations located in the poorly characterized cytosolic C-terminal domain. In this study, we characterized, through patch clamp, seven ClC-1 mutations identified in patients affected by MC of various severities and located in the C-terminal region. The p.Val829Met, p.Thr832Ile, p.Val851Met, p.Gly859Val, and p.Leu861Pro mutations reside in the CBS2 domain, while p.Pro883Thr and p.Val947Glu are in the C-terminal peptide. We showed that the functional properties of mutant channels correlated with the clinical phenotypes of affected individuals. In addition, we defined clusters of ClC-1 mutations within CBS2 and C-terminal peptide subdomains that share the same functional defect: mutations between 829 and 835 residues and in residue 883 induced an alteration of voltage dependence, mutations between 851 and 859 residues, and in residue 947 induced a reduction of chloride currents, whereas mutations on 861 residue showed no obvious change in ClC-1 function. This study improves our understanding of the mechanisms underlying MC, sheds light on the role of the C-terminal region in ClC-1 function, and provides information to develop new antimyotonic drugs.
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Affiliation(s)
- Concetta Altamura
- Department of Pharmacy-Drug Sciences, University of Bari Aldo Moro, Bari, Italy
| | - Sabrina Lucchiari
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Milan, Italy.,Neurology Unit, IRCCS Fondazione Ca' Grande Ospedale Maggiore Policlinico, Milan, Italy
| | - Dalila Sahbani
- Department of Pharmacy-Drug Sciences, University of Bari Aldo Moro, Bari, Italy
| | - Gianna Ulzi
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Milan, Italy.,Neurology Unit, IRCCS Fondazione Ca' Grande Ospedale Maggiore Policlinico, Milan, Italy
| | - Giacomo P Comi
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Milan, Italy.,Neurology Unit, IRCCS Fondazione Ca' Grande Ospedale Maggiore Policlinico, Milan, Italy
| | - Paola D'Ambrosio
- Cardiomyology and Medical Genetics, Department of Experimental Medicine, University of Campania, Naples, Italy
| | - Roberta Petillo
- Cardiomyology and Medical Genetics, Department of Experimental Medicine, University of Campania, Naples, Italy
| | - Luisa Politano
- Cardiomyology and Medical Genetics, Department of Experimental Medicine, University of Campania, Naples, Italy
| | - Liliana Vercelli
- Neuromuscular Unit, Department of Neurosciences, Hospital Città della Salute e della Scienza of Torino, University of Torino, Turin, Italy
| | - Tiziana Mongini
- Neuromuscular Unit, Department of Neurosciences, Hospital Città della Salute e della Scienza of Torino, University of Torino, Turin, Italy
| | - Maria Teresa Dotti
- Unit of Neurology and Neurometabolic Disorders, Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
| | - Rosanna Cardani
- Laboratory of Muscle Histopathology and Molecular Biology, IRCCS Policlinico San Donato, Milan, Italy
| | - Giovanni Meola
- Department of Biomedical Sciences for Health, University of Milan, IRCCS Policlinico San Donato, Milan, Italy
| | - Mauro Lo Monaco
- Institute of Neurology, Catholic University of Sacred Heart, Polyclinic Gemelli, Rome, Italy.,MiA Onlus ("Miotonici in Associazione"), Portici, Italy
| | - Emma Matthews
- MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology and National Hospital for Neurology and Neurosurgery, London, UK
| | - Michael G Hanna
- MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology and National Hospital for Neurology and Neurosurgery, London, UK
| | - Maria Rosaria Carratù
- Department of Biomedical Sciences and Human Oncology, University of Bari Aldo Moro, Polyclinic, Bari, Italy
| | - Diana Conte
- Department of Pharmacy-Drug Sciences, University of Bari Aldo Moro, Bari, Italy
| | - Paola Imbrici
- Department of Pharmacy-Drug Sciences, University of Bari Aldo Moro, Bari, Italy
| | - Jean-François Desaphy
- Department of Biomedical Sciences and Human Oncology, University of Bari Aldo Moro, Polyclinic, Bari, Italy
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Jentsch TJ, Pusch M. CLC Chloride Channels and Transporters: Structure, Function, Physiology, and Disease. Physiol Rev 2018; 98:1493-1590. [DOI: 10.1152/physrev.00047.2017] [Citation(s) in RCA: 214] [Impact Index Per Article: 35.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
CLC anion transporters are found in all phyla and form a gene family of eight members in mammals. Two CLC proteins, each of which completely contains an ion translocation parthway, assemble to homo- or heteromeric dimers that sometimes require accessory β-subunits for function. CLC proteins come in two flavors: anion channels and anion/proton exchangers. Structures of these two CLC protein classes are surprisingly similar. Extensive structure-function analysis identified residues involved in ion permeation, anion-proton coupling and gating and led to attractive biophysical models. In mammals, ClC-1, -2, -Ka/-Kb are plasma membrane Cl−channels, whereas ClC-3 through ClC-7 are 2Cl−/H+-exchangers in endolysosomal membranes. Biological roles of CLCs were mostly studied in mammals, but also in plants and model organisms like yeast and Caenorhabditis elegans. CLC Cl−channels have roles in the control of electrical excitability, extra- and intracellular ion homeostasis, and transepithelial transport, whereas anion/proton exchangers influence vesicular ion composition and impinge on endocytosis and lysosomal function. The surprisingly diverse roles of CLCs are highlighted by human and mouse disorders elicited by mutations in their genes. These pathologies include neurodegeneration, leukodystrophy, mental retardation, deafness, blindness, myotonia, hyperaldosteronism, renal salt loss, proteinuria, kidney stones, male infertility, and osteopetrosis. In this review, emphasis is laid on biophysical structure-function analysis and on the cell biological and organismal roles of mammalian CLCs and their role in disease.
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Affiliation(s)
- Thomas J. Jentsch
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany; and Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Genova, Italy
| | - Michael Pusch
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany; and Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Genova, Italy
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19
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Gaitán-Peñas H, Armand-Ugón M, Macaya A, Estévez R. CLCN1 Myotonia congenita mutation with a variable pattern of inheritance suggests a novel mechanism of dominant myotonia. Muscle Nerve 2018; 58:157-160. [PMID: 29424939 DOI: 10.1002/mus.26098] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/06/2018] [Indexed: 11/07/2022]
Abstract
INTRODUCTION Mutations in CLCN1 cause recessive or dominant forms of myotonia congenita (MC). Some mutations have been found to exhibit both patterns of inheritance but the mechanism explaining this behavior is unknown. METHODS A known recessive missense mutation, A493E, was identified in a family with dominant MC. The mutant p.A493E alone or in co-expression with wild-type (WT) ClC-1 was expressed in Xenopus oocytes. Currents were measured and biochemical assays were performed. RESULTS The mutant showed no significant activity and reduced total and plasma membrane (PM) protein levels. Co-expression with the mutant reduced the activity and PM levels of an engineered lower expression variant of ClC-1, whereas no effect was observed on a higher expression variant. DISCUSSION Our results suggest that the dominant effect of some CLCN1 mutations showing recessive or dominant inheritance patterns may be due to a dose-dependent defect in PM delivery of the WT channel. Muscle Nerve, 2018.
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Affiliation(s)
- Héctor Gaitán-Peñas
- Unitat de Fisiologia, Departament de Ciències Fisiològiques, IDIBELL-Universitat de Barcelona (Institut de Neurociències), L'Hospitalet de Llobregat, Spain
- U-750, CIBERER, ISCIII, Barcelona, Spain
| | - Mercedes Armand-Ugón
- Unitat de Fisiologia, Departament de Ciències Fisiològiques, IDIBELL-Universitat de Barcelona (Institut de Neurociències), L'Hospitalet de Llobregat, Spain
| | - Alfons Macaya
- Pediatric Neurology Research Group, Vall d'Hebron Research Institute, Hospital Universitari de Vall d'Hebron, Autonomous University of Barcelona, Barcelona, Spain
| | - Raúl Estévez
- Unitat de Fisiologia, Departament de Ciències Fisiològiques, IDIBELL-Universitat de Barcelona (Institut de Neurociències), L'Hospitalet de Llobregat, Spain
- U-750, CIBERER, ISCIII, Barcelona, Spain
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Structure of a CLC chloride ion channel by cryo-electron microscopy. Nature 2016; 541:500-505. [PMID: 28002411 PMCID: PMC5576512 DOI: 10.1038/nature20812] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 11/18/2016] [Indexed: 12/18/2022]
Abstract
CLC proteins transport chloride (Cl-) ions across cellular membranes to regulate muscle excitability, electrolyte movement across epithelia, and acidification of intracellular organelles. Some CLC proteins are channels that conduct Cl- ions passively, whereas others are secondary active transporters that exchange two Cl- ions for one H+. The structural basis underlying these distinctive transport mechanisms is puzzling because CLC channels and transporters are expected to share the same architecture on the basis of sequence homology. Here we determined the structure of a bovine CLC channel (CLC-K) using cryo-electron microscopy. A conserved loop in the Cl- transport pathway shows a structure markedly different from that of CLC transporters. Consequently, the cytosolic constriction for Cl- passage is widened in CLC-K such that the kinetic barrier previously postulated for Cl-/H+ transporter function would be reduced. Thus, reduction of a kinetic barrier in CLC channels enables fast flow of Cl- down its electrochemical gradient.
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