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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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Corrêa S, Basso RM, Cerri FM, de Oliveira‐Filho JP, Araújo JP, Torelli SR, Salán LPCDC, Salán MO, Macedo IZ, Borges AS. Hereditary myotonia in cats associated with a new homozygous missense variant p.Ala331Pro in the muscle chloride channel ClC-1. J Vet Intern Med 2023; 37:2498-2503. [PMID: 37668104 PMCID: PMC10658498 DOI: 10.1111/jvim.16837] [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: 03/31/2023] [Accepted: 08/16/2023] [Indexed: 09/06/2023] Open
Abstract
Three-related cats were evaluated for a history of short-strided gait and temporary recumbency after startle. Neurological examination, electromyography (EMG), muscle biopsies, and a chloride voltage-gated channel 1 (CLCN1) molecular study were performed. Clinically, all 3 cats presented myotonia with warm-up phenomenon and myotonic discharges during EMG examination. Muscle biopsies showed normal muscle architecture and variation in the diameter of myofiber size with the presence of numerous hypertrophic fibers. The molecular study revealed a missense variant (c.991G>C, p.Ala331Pro) in exon 9 of the CLCN1 gene, responsible for the first chloride channel extracellular loop. This mutation was screened in 104 control phenotypically normal unrelated cats, and all were wildtype. The alanine at this position is conserved in ClC-1 (chloride channel protein 1) in different species, and 2 mutations at this amino acid position are associated with human myotonia. This is the third CLCN1 mutation described in the literature associated with hereditary myotonia in cats and the first in domestic animals located in an extracellular muscle ClC-1 loop.
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Affiliation(s)
| | - Roberta Martins Basso
- School of Veterinary Medicine and Animal Science, São Paulo State University (UNESP)BotucatuSão PauloBrazil
| | - Fabricio Moreira Cerri
- School of Veterinary Medicine and Animal Science, São Paulo State University (UNESP)BotucatuSão PauloBrazil
| | | | - João Pessoa Araújo
- Institute of Biotechnology (IBTEC), São Paulo State University (UNESP)BotucatuSão PauloBrazil
| | | | | | | | | | - Alexandre Secorun Borges
- School of Veterinary Medicine and Animal Science, São Paulo State University (UNESP)BotucatuSão PauloBrazil
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Vicino A, Brugnoni R, Maggi L. Diagnostics in skeletal muscle channelopathies. Expert Rev Mol Diagn 2023; 23:1175-1193. [PMID: 38009256 DOI: 10.1080/14737159.2023.2288258] [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: 08/23/2023] [Accepted: 11/22/2023] [Indexed: 11/28/2023]
Abstract
INTRODUCTION Skeletal muscle channelopathies (SMCs) are a heterogenous group of disorders, caused by mutations in skeletal ion channels leading to abnormal muscle excitability, resulting in either delayed muscle relaxation (myotonia) which characterizes non-dystrophic myotonias (NDMs), or membrane transient inactivation, causing episodic weakness, typical of periodic paralyses (PPs). AREAS COVERED SMCs include myotonia congenita, paramyotonia congenita, and sodium-channel myotonia among NDMs, and hyper-normokalemic, hypokalemic, or late-onset periodic paralyses among PPs. When suspecting an SMC, a structured diagnostic approach is required. Detailed personal and family history and clinical examination are essential, while neurophysiological tests should confirm myotonia and rule out alternative diagnosis. Moreover, specific electrodiagnostic studies are important to further define the phenotype of de novo cases and drive molecular analyses together with clinical data. Definite diagnosis is achieved through genetic testing, either with Sanger sequencing or multigene next-generation sequencing panel. In still unsolved patients, more advanced techniques, as exome-variant sequencing or whole-genome sequencing, may be considered in expert centers. EXPERT OPINION The diagnostic approach to SMC is still mainly based on clinical data; moreover, definite diagnosis is sometimes complicated by the difficulty to establish a proper genotype-phenotype correlation. Lastly, further studies are needed to allow the genetic characterization of unsolved patients.
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Affiliation(s)
- Alex Vicino
- Neurology IV Unit, Neuroimmunology and Neuromuscular Diseases, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
- Nerve-Muscle Unit, Neurology Service, Department of Clinical Neurosciences, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - 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
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Einhorn Y, Einhorn M, Kurolap A, Steinberg D, Mory A, Bazak L, Paperna T, Grinshpun-Cohen J, Basel-Salmon L, Weiss K, Singer A, Yaron Y, Baris Feldman H. Community data-driven approach to identify pathogenic founder variants for pan-ethnic carrier screening panels. Hum Genomics 2023; 17:30. [PMID: 36978159 PMCID: PMC10044388 DOI: 10.1186/s40246-023-00472-w] [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: 08/21/2022] [Accepted: 03/15/2023] [Indexed: 03/30/2023] Open
Abstract
BACKGROUND The American College of Medical Genetics and Genomics (ACMG) recently published new tier-based carrier screening recommendations. While many pan-ethnic genetic disorders are well established, some genes carry pathogenic founder variants (PFVs) that are unique to specific ethnic groups. We aimed to demonstrate a community data-driven approach to creating a pan-ethnic carrier screening panel that meets the ACMG recommendations. METHODS Exome sequencing data from 3061 Israeli individuals were analyzed. Machine learning determined ancestries. Frequencies of candidate pathogenic/likely pathogenic (P/LP) variants based on ClinVar and Franklin were calculated for each subpopulation based on the Franklin community platform and compared with existing screening panels. Candidate PFVs were manually curated through community members and the literature. RESULTS The samples were automatically assigned to 13 ancestries. The largest number of samples was classified as Ashkenazi Jewish (n = 1011), followed by Muslim Arabs (n = 613). We detected one tier-2 and seven tier-3 variants that were not included in existing carrier screening panels for Ashkenazi Jewish or Muslim Arab ancestries. Five of these P/LP variants were supported by evidence from the Franklin community. Twenty additional variants were detected that are potentially pathogenic tier-2 or tier-3. CONCLUSIONS The community data-driven and sharing approaches facilitate generating inclusive and equitable ethnically based carrier screening panels. This approach identified new PFVs missing from currently available panels and highlighted variants that may require reclassification.
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Affiliation(s)
| | | | - Alina Kurolap
- The Genetics Institute and Genomics Center, Tel Aviv Sourasky Medical Center, 6 Weizmann St., Tel Aviv, Israel
| | | | - Adi Mory
- The Genetics Institute and Genomics Center, Tel Aviv Sourasky Medical Center, 6 Weizmann St., Tel Aviv, Israel
| | - Lily Bazak
- Beilinson Hospital, Rabin Medical Center, Recanati Genetics Institute, Petah Tikva, Israel
| | - Tamar Paperna
- Rambam Health Care Campus, The Genetics Institute, Haifa, Israel
| | | | - Lina Basel-Salmon
- Beilinson Hospital, Rabin Medical Center, Recanati Genetics Institute, Petah Tikva, Israel
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Karin Weiss
- Rambam Health Care Campus, The Genetics Institute, Haifa, Israel
- The Ruth and Bruce Faculty of Medicine, Technion - Israel Institute of Technology, Haifa, Israel
| | - Amihood Singer
- Community Genetic Services, Ministry of Health, Tel Aviv, Israel
| | - Yuval Yaron
- The Genetics Institute and Genomics Center, Tel Aviv Sourasky Medical Center, 6 Weizmann St., Tel Aviv, Israel
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Hagit Baris Feldman
- The Genetics Institute and Genomics Center, Tel Aviv Sourasky Medical Center, 6 Weizmann St., Tel Aviv, Israel.
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
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Öz Tunçer G, Sanri A, Aydin S, Hergüner ÖM, Özgün N, Kömür M, İçağasioğlu DF, Toker RT, Yilmaz S, Arslan EA, Güngör M, Kutluk G, Erol İ, Mert GG, Polat BG, Aksoy A. Clinical and Genetic Spectrum of Myotonia Congenita in Turkish Children. J Neuromuscul Dis 2023; 10:915-924. [PMID: 37355912 PMCID: PMC10578252 DOI: 10.3233/jnd-230046] [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] [Accepted: 06/02/2023] [Indexed: 06/26/2023]
Abstract
BACKGROUND Myotonia congenita is the most common form of nondystrophic myotonia and is caused by Mendelian inherited mutations in the CLCN1 gene encoding the voltage-gated chloride channel of skeletal muscle. OBJECTIVE The study aimed to describe the clinical and genetic spectrum of Myotonia congenita in a large pediatric cohort. METHODS Demographic, genetic, and clinical data of the patients aged under 18 years at time of first clinical attendance from 11 centers in different geographical regions of Türkiye were retrospectively investigated. RESULTS Fifty-four patients (mean age:15.2 years (±5.5), 76% males, with 85% Becker, 15% Thomsen form) from 40 families were included. Consanguineous marriage rate was 67%. 70.5% of patients had a family member with Myotonia congenita. The mean age of disease onset was 5.7 (±4.9) years. Overall 23 different mutations (2/23 were novel) were detected in 52 patients, and large exon deletions were identified in two siblings. Thomsen and Becker forms were observed concomitantly in one family. Carbamazepine (46.3%), mexiletine (27.8%), phenytoin (9.3%) were preferred for treatment. CONCLUSIONS The clinical and genetic heterogeneity, as well as the limited response to current treatment options, constitutes an ongoing challenge. In our cohort, recessive Myotonia congenita was more frequent and novel mutations will contribute to the literature.
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Affiliation(s)
- Gökçen Öz Tunçer
- Division of Pediatric Neurology, Department of Pediatrics, Faculty of Medicine, Ondokuz Mayıs University, Samsun, Türkiye
| | - Aslıhan Sanri
- Department of Pediatric Genetics, University of Health Sciences, Samsun Training and Research Hospital, Samsun, Türkiye
| | - Seren Aydin
- Division of Pediatric Neurology, Department of Pediatrics, Faculty of Medicine, Ondokuz Mayıs University, Samsun, Türkiye
| | - Özlem M. Hergüner
- Division of Pediatric Neurology, Department of Pediatrics, Faculty of Medicine, Çukurova University, Adana, Türkiye
| | - Nezir Özgün
- Division of Pediatric Neurology, Department of Pediatrics, Faculty of Medicine, Artuklu University, Mardin, Türkiye
| | - Mustafa Kömür
- Division of Pediatric Neurology, Department of Pediatrics, Faculty of Medicine, Mersin University, Mersin, Türkiye
| | - Dilara F. İçağasioğlu
- Division of Pediatric Neurology, Department of Pediatrics, Faculty of Medicine, Bezmialem Vakıf University, İstanbul, Türkiye
| | - Rabia Tütüncü Toker
- Department of Pediatric Neurology, University of Health Sciences, Bursa City Hospital, Bursa, Türkiye
| | - Sanem Yilmaz
- Division of Pediatric Neurology, Department of Pediatrics, Faculty of Medicine, Ege University, İzmir, Türkiye
| | - Elif Acar Arslan
- Division of Pediatric Neurology, Department of Pediatrics, Faculty of Medicine, Karadeniz Technical University, Trabzon, Türkiye
| | - Mesut Güngör
- Division of Pediatric Neurology, Department of Pediatrics, Faculty of Medicine, Kocaeli University, Kocaeli, Türkiye
| | - Gültekin Kutluk
- Department of Pediatric Neurolgy, University of Health Sciences, Antalya Training and Research Hospital, Antalya, Türkiye
| | - İlknur Erol
- Division of Pediatric Neurology, Department of Pediatrics, Faculty of Medicine, Başkent University, Adana, Türkiye
| | - Gülen Gül Mert
- Division of Pediatric Neurology, Department of Pediatrics, Faculty of Medicine, Çukurova University, Adana, Türkiye
| | - Burçin Gönüllü Polat
- Division of Pediatric Neurology, Department of Pediatrics, Faculty of Medicine, Mersin University, Mersin, Türkiye
| | - Ayşe Aksoy
- Division of Pediatric Neurology, Department of Pediatrics, Faculty of Medicine, Ondokuz Mayıs University, Samsun, Türkiye
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Cordenier A, Flamez A, de Ravel T, Gheldof A, Pannone L, De Asmundis C, Pappaert G, Bissay V. Case report: Coexistence of myotonia congenita and Brugada syndrome in one family. Front Neurol 2022; 13:1011956. [PMID: 36212636 PMCID: PMC9537820 DOI: 10.3389/fneur.2022.1011956] [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: 08/04/2022] [Accepted: 09/05/2022] [Indexed: 11/21/2022] Open
Abstract
Myotonia congenita is a rare neuromuscular disorder caused by CLCN1 mutations resulting in delayed muscle relaxation. Extramuscular manifestations are not considered to be present in chloride skeletal channelopathies, although recently some cardiac manifestations have been described. We report a family with autosomal dominant myotonia congenita and Brugada syndrome. Bearing in mind the previously reported cases of cardiac arrhythmias in myotonia congenita patients, we discuss the possible involvement of the CLCN1-gene mutations in primary cardiac arrhythmia.
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Affiliation(s)
- Ann Cordenier
- Department of Neurology, Center for Neurosciences, Vrije Universiteit Brussel (VUB), UZ-Brussel, Brussels, Belgium
- *Correspondence: Ann Cordenier
| | - Anja Flamez
- Department of Neurology, Center for Neurosciences, Vrije Universiteit Brussel (VUB), UZ-Brussel, Brussels, Belgium
| | - Thomy de Ravel
- Center for Medical Genetics, Vrije Universiteit Brussel (VUB), UZ-Brussel, Brussels, Belgium
| | - Alexander Gheldof
- Center for Medical Genetics, Vrije Universiteit Brussel (VUB), UZ-Brussel, Brussels, Belgium
| | - Luigi Pannone
- Heart Rhythm Management Centre, Vrije Universiteit Brussel (VUB), UZ-Brussel, Brussels, Belgium
| | - Carlo De Asmundis
- Heart Rhythm Management Centre, Vrije Universiteit Brussel (VUB), UZ-Brussel, Brussels, Belgium
| | - Gudrun Pappaert
- Heart Rhythm Management Centre, Vrije Universiteit Brussel (VUB), UZ-Brussel, Brussels, Belgium
| | - Véronique Bissay
- Department of Neurology, Center for Neurosciences, Vrije Universiteit Brussel (VUB), UZ-Brussel, Brussels, Belgium
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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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Altamura C, Conte E, Campanale C, Laghetti P, Saltarella I, Camerino GM, Imbrici P, Desaphy JF. Chaperone activity of niflumic acid on ClC-1 chloride channel mutants causing myotonia congenita. Front Pharmacol 2022; 13:958196. [PMID: 36034862 PMCID: PMC9403836 DOI: 10.3389/fphar.2022.958196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 07/08/2022] [Indexed: 11/14/2022] Open
Abstract
Myotonia congenita (MC) is an inherited rare disease characterized by impaired muscle relaxation after contraction, resulting in muscle stiffness. It is caused by loss-of-function mutations in the skeletal muscle chloride channel ClC-1, important for the stabilization of resting membrane potential and for the repolarization phase of action potentials. Thanks to in vitro functional studies, the molecular mechanisms by which ClC-1 mutations alter chloride ion influx into the cell have been in part clarified, classifying them in “gating-defective” or “expression-defective” mutations. To date, the treatment of MC is only palliative because no direct ClC-1 activator is available. An ideal drug should be one which is able to correct biophysical defects of ClC-1 in the case of gating-defective mutations or a drug capable to recover ClC-1 protein expression on the plasma membrane for trafficking-defective ones. In this study, we tested the ability of niflumic acid (NFA), a commercial nonsteroidal anti-inflammatory drug, to act as a pharmacological chaperone on trafficking-defective MC mutants (A531V, V947E). Wild-type (WT) or MC mutant ClC-1 channels were expressed in HEK293 cells and whole-cell chloride currents were recorded with the patch-clamp technique before and after NFA incubation. Membrane biotinylation assays and western blot were performed to support electrophysiological results. A531V and V947E mutations caused a decrease in chloride current density due to a reduction of ClC-1 total protein level and channel expression on the plasma membrane. The treatment of A531V and V947E-transfected cells with 50 µM NFA restored chloride currents, reaching levels similar to those of WT. Furthermore, no significant difference was observed in voltage dependence, suggesting that NFA increased protein membrane expression without altering the function of ClC-1. Indeed, biochemical experiments confirmed that V947E total protein expression and its plasma membrane distribution were recovered after NFA incubation, reaching protein levels similar to WT. Thus, the use of NFA as a pharmacological chaperone in trafficking defective ClC-1 channel mutations could represent a good strategy in the treatment of MC. Because of the favorable safety profile of this drug, our study may easily open the way for confirmatory human pilot studies aimed at verifying the antimyotonic activity of NFA in selected patients carrying specific ClC-1 channel mutations.
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Affiliation(s)
- Concetta Altamura
- Dept. of Biomedical Sciences and Human Oncology, School of Medicine, University of Bari Aldo Moro, Bari, Italy
- *Correspondence: Concetta Altamura,
| | - Elena Conte
- Dept. of Pharmacy-Drug Sciences, University of Bari Aldo Moro, Bari, Italy
| | - Carmen Campanale
- Dept. of Biomedical Sciences and Human Oncology, School of Medicine, University of Bari Aldo Moro, Bari, Italy
| | - Paola Laghetti
- Dept. of Biomedical Sciences and Human Oncology, School of Medicine, University of Bari Aldo Moro, Bari, Italy
| | - Ilaria Saltarella
- Dept. of Biomedical Sciences and Human Oncology, School of Medicine, University of Bari Aldo Moro, Bari, Italy
| | | | - Paola Imbrici
- Dept. of Pharmacy-Drug Sciences, University of Bari Aldo Moro, Bari, Italy
| | - Jean-François Desaphy
- Dept. of Biomedical Sciences and Human Oncology, School of Medicine, University of Bari Aldo Moro, Bari, Italy
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9
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Li Y, Li M, Wang Z, Yang F, Wang H, Bai X, Sun B, Chen S, Huang X. Clinical and molecular characteristics of myotonia congenita in China: Case series and a literature review. Channels (Austin) 2022; 16:35-46. [PMID: 35170402 PMCID: PMC8855856 DOI: 10.1080/19336950.2022.2041292] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Myotonia congenita (MC) is a rare genetic disease caused by mutations in the skeletal muscle chloride channel gene (CLCN1), encoding the voltage-gated chloride channel ClC-1 in skeletal muscle. Our study reported the clinical and molecular characteristics of six patients with MC and systematically review the literature on Chinese people. We retrospectively analyzed demographics, clinical features, family history, creatine kinase (CK), electromyography (EMG), treatment, and genotype data of our patients and reviewed the clinical data and CLCN1 mutations in literature. The median ages at examination and onset were 26.5 years (range 11–50 years) and 6.5 years (range 1.5–11 years), respectively, in our patients, and 21 years (range 3.5–65 years, n = 45) and 9 years (range 0.5–26 years, n = 50), respectively, in literature. Similar to previous reports, myotonia involved limb, lids, masticatory, and trunk muscles to varying degrees. Warm-up phenomenon (5/6), percussion myotonia (3/5), and grip myotonia (6/6) were common. Menstruation triggered myotonia in females, not observed in Chinese patients before. The proportion of abnormal CK levels (4/5) was higher than data from literature. Electromyography performed in six patients revealed myotonic changes (100%). Five novel CLCN1 mutations, including a splicing mutation (c.853 + 4A>G), a deletion mutation (c.2010_2014del), and three missense mutations (c.2527C>T, c.1727C>T, c.2017 G > C), were identified. The c.892 G > A (p.A298T) mutation was the most frequent mutation in the Chinese population. Our study expanded the clinical and genetic spectrum of patients with MC in the China. The MC phenotype in Chinese people is not different from that found in the West, while the genotype is different.
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Affiliation(s)
- Yifan Li
- Geriatric Neurological Department of the Second Medical Center & National Clinical Research Center for Geriatric Diseases, Chinese Pla General Hospital, Beijing, China
| | - Mao Li
- Department of Neurology of the First Medical Center, Chinese Pla General Hospital, Beijing, China
| | - Zhenfu Wang
- Geriatric Neurological Department of the Second Medical Center & National Clinical Research Center for Geriatric Diseases, Chinese Pla General Hospital, Beijing, China
| | - Fei Yang
- Department of Neurology of the First Medical Center, Chinese Pla General Hospital, Beijing, China
| | - Hongfen Wang
- Department of Neurology of the First Medical Center, Chinese Pla General Hospital, Beijing, China
| | - Xiujuan Bai
- Geriatric Neurological Department of the Second Medical Center & National Clinical Research Center for Geriatric Diseases, Chinese Pla General Hospital, Beijing, China
| | - Bo Sun
- Geriatric Neurological Department of the Second Medical Center & National Clinical Research Center for Geriatric Diseases, Chinese Pla General Hospital, Beijing, China
| | - Siyu Chen
- Geriatric Neurological Department of the Second Medical Center & National Clinical Research Center for Geriatric Diseases, Chinese Pla General Hospital, Beijing, China
| | - Xusheng Huang
- Department of Neurology of the First Medical Center, Chinese Pla General Hospital, Beijing, China
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10
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Olave-Rodriguez JA, Bonilla-Escobar FJ, Candelo E, Rodriguez-Rojas LX. First Two Case Reports of Becker's Type Myotonia Congenita in Colombia: Clinical and Genetic Features. Appl Clin Genet 2021; 14:473-479. [PMID: 34938096 PMCID: PMC8687676 DOI: 10.2147/tacg.s323559] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Accepted: 10/26/2021] [Indexed: 11/23/2022] Open
Abstract
Background Becker's type myotonia congenita is an autosomal recessive nondystrophic skeletal muscle disorder characterized by muscle stiffness and the inability of muscle relaxation after voluntary contraction. It is caused by mutations in the CLCN1 gene, which encodes for a chloride channel mainly expressed in the striated muscle. Most cases have been reported in the European population, and only mexiletine has demonstrated a randomized placebo-controlled, double-blinded effectiveness. Case Presentation We present two male siblings from Colombia with Latino ancestry, without parental consanguinity, with myotonia during voluntary movements, muscle hypertrophy of lower extremities, transient weakness, and severe muscle fatigue after exercise from three years of age. A genetic panel for dystrophic muscle disorders and a muscle biopsy were both negative. Genetic testing was performed in their second decade of life. Both patients' exomic sequencing test reported the mutation c.1129C >T (p.Arg377*) affecting exon 10 of the CLCN1, generating a premature stop codon. This mutation was described as pathogenic and observed in only one other patient in the United Kingdom. Conclusion To our knowledge, these are the first cases of Becker's type myotonia congenita reported in Colombia. Increasing awareness of healthcare providers for this type of disease in the region could lead to the identification of undiagnosed patients. Limited availability of medical geneticists as well as genetic testing may be the cause of the lack of previous description of cases, in addition to the delay in the diagnosis of the patients. Further epidemiological studies can reveal underdiagnosed myotonias in the country and in the Latin-American region.
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Affiliation(s)
| | - Francisco Javier Bonilla-Escobar
- Somos Ciencia al Servicio de la Comunidad, Fundación SCISCO/Science to Serve the Community, SCISCO Foundation, Cali, Colombia.,Universidad del Valle, Cali, Colombia.,Institute for Clinical Research Education, University of Pittsburgh, Pittsburgh, PA, USA
| | - Estephania Candelo
- Centro de Investigaciones Clínicas, Fundación Valle del Lili, Cali, Colombia.,Centro enfermedades raras y malformaciones congenitas (CIACER), Universidad Icesi, Cali, Colombia
| | - Lisa Ximena Rodriguez-Rojas
- Universidad Icesi, Faculty of Health Sciences, Cali, Colombia.,Human Genetics Department, Fundación Valle del Lili, Cali, Colombia
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11
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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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12
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Souza LS, Calyjur P, Ribeiro AF, Gurgel-Giannetti J, Pavanello RCM, Zatz M, Vainzof M. Association of Three Different Mutations in the CLCN1 Gene Modulating the Phenotype in a Consanguineous Family with Myotonia Congenita. J Mol Neurosci 2021; 71:2275-2280. [PMID: 33464536 DOI: 10.1007/s12031-020-01785-4] [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: 07/23/2020] [Accepted: 12/25/2020] [Indexed: 11/29/2022]
Abstract
Myotonia congenita is a genetic disease caused by mutations in the CLCN1 gene, which encodes for the major chloride skeletal channel ClC-1, involved in the normal repolarization of muscle action potentials and consequent relaxation of the muscle after contraction. Two allelic forms are recognized, depending on the phenotype and the inheritance pattern: the autosomal dominant Thomsen disease with milder symptoms and the autosomal recessive Becker disorder with a severe phenotype. Before the recent advances of molecular testing, the diagnosis and genetic counseling of families was a challenge due to the large number of mutations in the CLCN1 gene, found both in homozygous or in heterozygous state. Here, we studied a consanguineous family in which three members presented a variable phenotype of myotonia, associated to a combination of three different mutations in the CLCN1 gene. A pathogenic splicing site mutation which causes the skipping of exon 17 was present in homozygosis in one very severely affected son. This mutation was present in compound heterozygosis in the consanguineous parents, but interestingly it was associated to a different second variant in the other allele: c.1453 A > G in the mother and c.1842 G > C in the father. Both displayed variable, but less severe phenotypes than their homozygous son. These results highlight the importance of analyzing the combination of different variants in the same gene in particular in families with patients displaying different phenotypes. This approach may improve the diagnosis, prognosis, and genetic counseling of the involved families.
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Affiliation(s)
- Lucas Santos Souza
- Human Genome and stem cells Research Center, Biosciences Institute, University of São Paulo, São Paulo, Brazil
| | - Priscila Calyjur
- Human Genome and stem cells Research Center, Biosciences Institute, University of São Paulo, São Paulo, Brazil
| | - Antonio Fernando Ribeiro
- Human Genome and stem cells Research Center, Biosciences Institute, University of São Paulo, São Paulo, Brazil
| | - Juliana Gurgel-Giannetti
- Human Genome and stem cells Research Center, Biosciences Institute, University of São Paulo, São Paulo, Brazil
- Pediatrics Department, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | | | - Mayana Zatz
- Human Genome and stem cells Research Center, Biosciences Institute, University of São Paulo, São Paulo, Brazil
| | - Mariz Vainzof
- Human Genome and stem cells Research Center, Biosciences Institute, University of São Paulo, São Paulo, Brazil.
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13
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Hu C, Shi Y, Zhao L, Zhou S, Li X. Myotonia Congenita: Clinical Characteristic and Mutation Spectrum of CLCN1 in Chinese Patients. Front Pediatr 2021; 9:759505. [PMID: 34790634 PMCID: PMC8591224 DOI: 10.3389/fped.2021.759505] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 09/28/2021] [Indexed: 12/03/2022] Open
Abstract
Background: CLCN1-related myotonia congenita (MC) is one of the most common forms of non-dystrophic myotonia, in which muscle relaxation is delayed after voluntary or evoked contraction. However, there is limited data of clinical and molecular spectrum of MC patients in China. Patients and Methods: Five patients with myotonia congenita due to mutations in CLCN1 gene were enrolled, which were identified through trio-whole-exome sequencing or panel-based next-generation sequencing test. The clinical presentation, laboratory data, electrophysiological tests, muscular pathology feature, and genetic results were collected and reviewed. We also searched all previously reported cases of MC patients with genetic diagnosis in Chinese populations, and their data were reviewed. Results: The median onset age of five patients was 3.0 years old, ranging from 1.0 to 5.0 years old, while the median age of admit was 5.0 years old, ranging from 3.5 to 8.8 years old. Five patients complained of muscle stiffness when rising from chairs or starting to climb stairs (5/5, 100.0%), four patients complained of delayed relaxation of their hands after forceful grip (4/5, 80.0%), all of which improved with exercise (warm-up phenomenon) (5/5, 100%). Electromyogram was conducted in five patients, which all revealed myotonic change (100%). Genetic tests revealed nine potential disease-causing variants in CLCN1 gene, including two novel variants: c.962T>A (p.V321E) and c.1250A>T (p.E417V). Literature review showed that 43 MC Chinese patients with genetic diagnosis have been reported till now (including our five patients). Forty-seven variants in CLCN1 gene were found, which consisted of 33 missense variants, 6 nonsense variants, 5 frame-shift variants, and 3 splicing variants. Variants in exon 8, 15, 12, and 16 were most prevalent, while the most common variants were c.892G>A (p.A298T) (n = 9), c.139C>T (p.R47W) (n = 3), c.1205C>T(p.A402V) (n = 3), c.1657A>T (p.I553F) (n = 3), c.1679T>C (p.M560T) (n = 3), c.350A>G (p.D117G) (n = 2), c.762C>G (p.C254W) (n = 2), c.782A>G (P.Y261C) (n = 2), and c.1277C>A (p.T426N) (n = 2). Conclusion: Our results reported five CLCN1-related MC patients, which expanded the clinical and genetic spectrum of MC patients in China. Based on literature review, 43MC Chinese patients with genetic diagnosis have been reported till now, and variants in exon eight were most prevalent in Chinese MC patients while c.892G>A (p.A298T) was probably a founder mutation.
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Affiliation(s)
- Chaoping Hu
- Department of Neurology, Children's Hospital of Fudan University, Shanghai, China
| | - Yiyun Shi
- Department of Neurology, Children's Hospital of Fudan University, Shanghai, China
| | - Lei Zhao
- Department of Neurology, Children's Hospital of Fudan University, Shanghai, China
| | - Shuizhen Zhou
- Department of Neurology, Children's Hospital of Fudan University, Shanghai, China
| | - Xihua Li
- Department of Neurology, Children's Hospital of Fudan University, Shanghai, China
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14
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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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15
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Non-dystrophic myotonias: clinical and mutation spectrum of 70 German patients. J Neurol 2020; 268:1708-1720. [PMID: 33263785 PMCID: PMC8068660 DOI: 10.1007/s00415-020-10328-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 11/09/2020] [Accepted: 11/19/2020] [Indexed: 12/17/2022]
Abstract
Introduction Non-dystrophic myotonias (NDM) are heterogeneous diseases caused by mutations in CLCN1 and SCN4A. The study aimed to describe the clinical and genetic spectrum of NDM in a large German cohort. Methods We retrospectively identified all patients with genetically confirmed NDM diagnosed in our center. The following data were analyzed: demographics, family history, muscular features, cardiac involvement, CK, EMG, genotype, other tested genes, treatment perceived efficacy. Results 70 patients (age 40.2 years ± 14.9; 52.8% males) were included in our study (48 NDM-CLCN1, 22 NDM-SCN4A). The most frequent presenting symptoms were myotonia (NDM-CLCN1 83.3%, NDM-SCN4A 72.2%) and myalgia (NDM-CLCN1 57.4%, NDM-SCN4A 52.6%). Besides a more prominent facial involvement in NDM-SCN4A and cold-sensitivity in NDM-CLCN1, no other significant differences were observed between groups. Cardiac arrhythmia or conduction defects were documented in sixNDM-CLCN1 patients (three of them requiring a pacemaker) and one patient with NDM-SCN4A. CK was normal in 40% of patients. Myotonic runs in EMG were detected in 89.1% of CLCN1 and 78.9% of SCN4A. 50% of NDM-CLCN1 patients had the classic c.2680C>T (p.Arg894*) mutation. 12 new genetic variants are reported. About 50% of patients were not taking any anti-myotonic drug at the last follow-up. The anti-myotonic drugs with the best patient’s perceived efficacy were mexiletine and lamotrigine. Conclusion This study highlights the relevant clinical overlap between NDM-CLCN1 and NDM-SCN4A patients and warrants the use of early and broad genetic investigation for the precise identification of the NDM subtype. Besides the clinical and genetic heterogeneity, the limited response to current anti-myotonic drugs constitutes a continuing challenge. Supplementary Information The online version contains supplementary material available at 10.1007/s00415-020-10328-1.
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16
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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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17
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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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18
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Orsini C, Petillo R, D'Ambrosio P, Ergoli M, Picillo E, Scutifero M, Passamano L, De Luca A, Politano L. CLCN1 Molecular Characterization in 19 South-Italian Patients With Dominant and Recessive Type of Myotonia Congenita. Front Neurol 2020; 11:63. [PMID: 32117024 PMCID: PMC7016095 DOI: 10.3389/fneur.2020.00063] [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: 09/25/2019] [Accepted: 01/17/2020] [Indexed: 11/13/2022] Open
Abstract
Myotonia congenita is a genetic disease characterized by impaired muscle relaxation after forceful contraction (myotonia). It is caused by mutations in the CLCN1 gene, encoding the voltage-gated chloride channel of skeletal muscle, ClC-1. According to the pattern of inheritance, two distinct clinical forms have been described, Thomsen disease, inherited as an autosomal dominant trait and Becker disease inherited as an autosomal recessive trait. We report genetic and clinical data concerning 19 patients−13 familial and six isolated cases—all but one originating from the Campania Region, in southern Italy. Twelve patients (63.2%) present Becker type myotonia and 7 (36.8%) Thomsen type. Sex ratio M:F in Becker type is 6:6, while in Thomsen myotonia 4:3. The age of onset of the disease ranged from 2 to 15 years in Becker patients, and from 4 to 20 years in Thomsen. Overall 18 mutations were identified, 10 located in the coding part of the gene (exons 1, 3, 4, 5, 7, 8, 13, 15, 21, 22), and four in the intron part (introns 1, 2, 10, 18). All the exon mutations but two were missense mutations. Some of them, such as c.2551 G > A, c.817G > A and c.86A > C recurred more frequently. About 70% of mutations was inherited with an autosomal recessive pattern, two (c.86A and c.817G>A) with both mechanisms. Three novel mutations were identified, never described in the literature: p.Gly276Ser, p.Phe486Ser, and p.Gln812*, associated with Becker phenotype. Furthermore, we identified three CLCN1 mutations—c.86A>C + c.2551G > A, c.313C > T + c.501C > G and 899G > A + c.2284+5C > T, two of them inherited in cis on the same allele, in three unrelated families. The concomitant occurrence of both clinical pictures—Thomsen and Becker—was observed in one family. Intra-familial phenotypic variability was observed in two families, one with Becker phenotype, and one with Thomsen disease. In the latter an incomplete penetrance was hypothesized.
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Affiliation(s)
- Chiara Orsini
- Cardiomiology and Medical Genetics, Department of Experimental Medicine, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Roberta Petillo
- Cardiomiology and Medical Genetics, Department of Experimental Medicine, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Paola D'Ambrosio
- Cardiomiology and Medical Genetics, Department of Experimental Medicine, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Manuela Ergoli
- Cardiomiology and Medical Genetics, Department of Experimental Medicine, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Esther Picillo
- Cardiomiology and Medical Genetics, Department of Experimental Medicine, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Marianna Scutifero
- Cardiomiology and Medical Genetics, Department of Experimental Medicine, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Luigia Passamano
- Cardiomiology and Medical Genetics, Department of Experimental Medicine, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Alessandro De Luca
- Cardiomiology and Medical Genetics, Department of Experimental Medicine, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Luisa Politano
- Cardiomiology and Medical Genetics, Department of Experimental Medicine, University of Campania "Luigi Vanvitelli", Naples, Italy
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19
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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: 28] [Impact Index Per Article: 7.0] [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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20
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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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21
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Palma Milla C, Prior De Castro C, Gómez-González C, Martínez-Montero P, I. Pascual Pascual S, Molano Mateos J. Myotonia congenita: mutation spectrum of CLCN1 in Spanish patients. J Genet 2019. [DOI: 10.1007/s12041-019-1115-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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22
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Becker's myotonia: novel mutations and clinical variability in patients born to consanguineous parents. Acta Neurol Belg 2018; 118:567-572. [PMID: 29480456 DOI: 10.1007/s13760-018-0893-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 02/05/2018] [Indexed: 01/30/2023]
Abstract
Myotonia congenita is an inherited muscle disease present from childhood that is characterized by impaired muscle relaxation after contraction resulting in muscle stiffness; moreover, skeletal striated muscle groups may be involved. Myotonia congenita occurs due to chloride (Cl) channel mutations that reduce the stabilizing Cl conductance, and it is caused by mutations in the CLCN1 gene. This paper describes four patients from two different healthy consanguineous Turkish families with muscle stiffness and easy fatigability. A genetic investigation was performed. Mutation analyses showed a homozygous p.Tyr150* (c.450C > A) mutation in patients 1, 2 and 3 and a homozygous p.Leu159Cysfs*11 (c.475delC) mutation in patient 4 in the CLCN1 gene. These mutations have never been reported before and in silico analyses showed that the mutations were disease causing. They may be predicted to cause nonsense-mediated mRNA decay. Our data expand the spectrum of CLCN1 mutations and provide insights for genotype-phenotype correlations of myotonia congenita.
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23
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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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24
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Altamura C, Mangiatordi GF, Nicolotti O, Sahbani D, Farinato A, Leonetti F, Carratù MR, Conte D, Desaphy JF, Imbrici P. Mapping ligand binding pockets in chloride ClC-1 channels through an integrated in silico and experimental approach using anthracene-9-carboxylic acid and niflumic acid. Br J Pharmacol 2018; 175:1770-1780. [PMID: 29500929 DOI: 10.1111/bph.14192] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 02/19/2018] [Accepted: 02/23/2018] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND AND PURPOSE Although chloride channels are involved in several physiological processes and acquired diseases, the availability of compounds selectively targeting CLC proteins is limited. ClC-1 channels are responsible for sarcolemma repolarization after an action potential in skeletal muscle and have been associated with myotonia congenita and myotonic dystrophy as well as with other muscular physiopathological conditions. To date only a few ClC-1 blockers have been discovered, such as anthracene-9-carboxylic acid (9-AC) and niflumic acid (NFA), whereas no activator exists. The absence of a ClC-1 structure and the limited information regarding the binding pockets in CLC channels hamper the identification of improved modulators. EXPERIMENTAL APPROACH Here we provide an in-depth characterization of drug binding pockets in ClC-1 through an integrated in silico and experimental approach. We first searched putative cavities in a homology model of ClC-1 built upon an eukaryotic CLC crystal structure, and then validated in silico data by measuring the blocking ability of 9-AC and NFA on mutant ClC-1 channels expressed in HEK 293 cells. KEY RESULTS We identified four putative binding cavities in ClC-1. 9-AC appears to interact with residues K231, R421 and F484 within the channel pore. We also identified one preferential binding cavity for NFA and propose R421 and F484 as critical residues. CONCLUSIONS AND IMPLICATIONS This study represents the first effort to delineate the binding sites of ClC-1. This information is fundamental to discover compounds useful in the treatment of ClC-1-associated dysfunctions and might represent a starting point for specifically targeting other CLC proteins.
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Affiliation(s)
- C Altamura
- Department of Pharmacy - Drug Sciences, University of Bari 'Aldo Moro', Bari, Italy
| | - G F Mangiatordi
- Department of Pharmacy - Drug Sciences, University of Bari 'Aldo Moro', Bari, Italy
| | - O Nicolotti
- Department of Pharmacy - Drug Sciences, University of Bari 'Aldo Moro', Bari, Italy
| | - D Sahbani
- Department of Pharmacy - Drug Sciences, University of Bari 'Aldo Moro', Bari, Italy
| | - A Farinato
- Department of Pharmacy - Drug Sciences, University of Bari 'Aldo Moro', Bari, Italy
| | - F Leonetti
- Department of Pharmacy - Drug Sciences, University of Bari 'Aldo Moro', Bari, Italy
| | - M R Carratù
- Department of Biomedical Sciences and Human Oncology, University of Bari 'Aldo Moro', Bari, Italy
| | - D Conte
- Department of Pharmacy - Drug Sciences, University of Bari 'Aldo Moro', Bari, Italy
| | - J-F Desaphy
- Department of Biomedical Sciences and Human Oncology, University of Bari 'Aldo Moro', Bari, Italy
| | - P Imbrici
- Department of Pharmacy - Drug Sciences, University of Bari 'Aldo Moro', Bari, Italy
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25
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Maggi L, Ravaglia S, Farinato A, Brugnoni R, Altamura C, Imbrici P, Camerino DC, Padovani A, Mantegazza R, Bernasconi P, Desaphy JF, Filosto M. Coexistence of CLCN1 and SCN4A mutations in one family suffering from myotonia. Neurogenetics 2017; 18:219-225. [PMID: 28993909 DOI: 10.1007/s10048-017-0525-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 10/01/2017] [Indexed: 01/28/2023]
Abstract
Non-dystrophic myotonias are characterized by clinical overlap making it challenging to establish genotype-phenotype correlations. We report clinical and electrophysiological findings in a girl and her father concomitantly harbouring single heterozygous mutations in SCN4A and CLCN1 genes. Functional characterization of N1297S hNav1.4 mutant was performed by patch clamp. The patients displayed a mild phenotype, mostly resembling a sodium channel myotonia. The CLCN1 c.501C>G (p.F167L) mutation has been already described in recessive pedigrees, whereas the SCN4A c.3890A>G (p.N1297S) variation is novel. Patch clamp experiments showed impairment of fast and slow inactivation of the mutated Nav1.4 sodium channel. The present findings suggest that analysis of both SCN4A and CLCN1 genes should be considered in myotonic patients with atypical clinical and neurophysiological features.
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Affiliation(s)
- Lorenzo Maggi
- Neurology IV - Neuroimmunology and Neuromuscular Diseases Unit, Fondazione IRCCS Istituto Neurologico "Carlo Besta", Via Celoria 11, 20133, Milan, Italy.
| | | | - Alessandro Farinato
- Department of Pharmacy and Drug Sciences, University of Bari Aldo Moro, Bari, Italy
| | - Raffaella Brugnoni
- Neurology IV - Neuroimmunology and Neuromuscular Diseases Unit, Fondazione IRCCS Istituto Neurologico "Carlo Besta", Via Celoria 11, 20133, Milan, Italy
| | - Concetta Altamura
- Department of Pharmacy and Drug Sciences, University of Bari Aldo Moro, Bari, Italy
| | - Paola Imbrici
- Department of Pharmacy and Drug Sciences, University of Bari Aldo Moro, Bari, Italy
| | - Diana Conte Camerino
- Department of Pharmacy and Drug Sciences, University of Bari Aldo Moro, Bari, Italy
| | - Alessandro Padovani
- Center for Neuromuscular Diseases and Neuropathies, Unit of Neurology ASST "Spedali Civili", University of Brescia, Brescia, Italy
| | - Renato Mantegazza
- Neurology IV - Neuroimmunology and Neuromuscular Diseases Unit, Fondazione IRCCS Istituto Neurologico "Carlo Besta", Via Celoria 11, 20133, Milan, Italy
| | - Pia Bernasconi
- Neurology IV - Neuroimmunology and Neuromuscular Diseases Unit, Fondazione IRCCS Istituto Neurologico "Carlo Besta", Via Celoria 11, 20133, Milan, Italy
| | - Jean-François Desaphy
- Department of Biomedical Sciences and Human Oncology, University of Bari Aldo Moro, Bari, Italy
| | - Massimiliano Filosto
- Center for Neuromuscular Diseases and Neuropathies, Unit of Neurology ASST "Spedali Civili", University of Brescia, Brescia, Italy
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26
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Meng YX, Zhao Z, Shen HR, Bing Q, Hu J. Identification of novel mutations of the CLCN1 gene for myotonia congenital in China. Neurol Res 2017; 38:40-4. [PMID: 27118449 DOI: 10.1080/01616412.2015.1114741] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
OBJECTIVES The identification of disease-specific genetic and electrophysiological patterns for myotonia congenital (MC) could help clinicians apply in the findings of genetic studies to improve diagnosis. We examined the molecular, clinical, and histopathological characteristics of eight patients with MC. METHODS Optimization PCR was used to exclude myotonic dystrophies and the CLCN1 gene was sequenced in patients having clinical and electrophysiological features indicative of MC. RESULTS Genetic screening identified nine CLCN1 mutations among the eight patients, including two missense, three nonsense, two insertion, and two deletion mutations. The patients showed typical myotonia and muscle hypertrophy. In contrast to the previous studies, secondary dystonia, joint contracture, and abnormal cardiac activity were also observed. Patients with novel mutations did not show any new muscle pathology compared with established mutations. Disscussion: Molecular genetics analysis offers an accurate method for diagnosing MC. The results of this analysis should be considered alongside clinical and electrophysiological characteristics. In this study, novel mutations in CLCN1 were detected, and the spectrum of CLCN1 mutations known to be associated with MC was expanded.
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Affiliation(s)
- Yan-Xin Meng
- a Department of Neuromuscular Disorders , The Third Hospital of Hebei Medical University , Shijiazhuang , China
| | - Zhe Zhao
- a Department of Neuromuscular Disorders , The Third Hospital of Hebei Medical University , Shijiazhuang , China
| | - Hong-Rui Shen
- a Department of Neuromuscular Disorders , The Third Hospital of Hebei Medical University , Shijiazhuang , China
| | - Qi Bing
- a Department of Neuromuscular Disorders , The Third Hospital of Hebei Medical University , Shijiazhuang , China
| | - Jing Hu
- a Department of Neuromuscular Disorders , The Third Hospital of Hebei Medical University , Shijiazhuang , China
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27
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Cassone M, Ferradini V, Longo G, Sarchielli P, Murasecco D, Romoli M, Pasquini E, Novelli G, Prontera P, Sangiuolo F. Genotype-phenotype correlation of F484L mutation in three Italian families with Thomsen myotonia. Muscle Nerve 2016; 55:E24-E25. [PMID: 27639085 DOI: 10.1002/mus.25407] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Marco Cassone
- Department of Biomedicine and Prevention, University Tor Vergata Rome, Italy
| | - Valentina Ferradini
- Department of Biomedicine and Prevention, University Tor Vergata Rome, Italy
| | - Giuliana Longo
- Department of Biomedicine and Prevention, University Tor Vergata Rome, Italy
| | - Paola Sarchielli
- Clinica Neurologica, Azienda Ospedaliera-Università di Perugia, Perugia, Italy
| | - Donatella Murasecco
- Clinica Neurologica, Azienda Ospedaliera-Università di Perugia, Perugia, Italy
| | - Michele Romoli
- Clinica Neurologica, Azienda Ospedaliera-Università di Perugia, Perugia, Italy
| | | | - Giuseppe Novelli
- Department of Biomedicine and Prevention, University Tor Vergata Rome, Italy
| | - Paolo Prontera
- Centro di Riferimento Regionale di Genetica Medica, Azienda Ospedaliera di Perugia, Perugia, Italy
| | - Federica Sangiuolo
- Department of Biomedicine and Prevention, University Tor Vergata Rome, Italy
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28
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Tincheva S, Georgieva B, Todorov T, Savov A, Tsaneva S, Litvinenko I, Mitev V, Todorova A. Myotonia congenita type Becker in Bulgaria: First genetically proven cases and mutation screening of two presumable endemic regions. Neuromuscul Disord 2016; 26:675-680. [PMID: 27614575 DOI: 10.1016/j.nmd.2016.08.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2016] [Revised: 08/03/2016] [Accepted: 08/04/2016] [Indexed: 11/30/2022]
Abstract
Myotonia congenita type Becker is an autosomal recessive nondystrophic skeletal muscle disorder, caused by mutations in the CLCN1 gene. The disease is characterized by muscle stiffness and an inability of the muscle to relax after voluntary contraction. Here we report the results from molecular genetic testing of 6 families, referred for sequencing of the CLCN1 gene. The disease causing mutations were detected in 5 of the cases, representing diverse type of nucleotide changes: nonsense (p.Arg894*), splice-site (c.1471+1G>A), missense (p.Val273Met; p.Tyr524Cys). Two additional changes were detected in an asymptomatic individual (c.2284+5C>T and p.Phe167Leu). Two of the detected mutations are interesting from population point of view. The novel missense mutation p.Tyr524Cys was found in a large Bulgarian family with affected individuals in both vertical and horizontal pedigree directions, all of them carrying the mutation in homozygous form. They populate a village located in the northwest part of the country. Endogamous marriages are very unusual for the Bulgarian population, supposing a high carrier frequency in this subpopulation. Screening of 154 residents of the corresponding region showed a significant carrier frequency for the p.Tyr524Cys mutation of about 0.65% (1/154). The second interesting region in the context of Myotonia congenita type Becker is the southwest part of the country, where we found a large family of Bulgarian Turkish origin. The disease causing missense mutation p.Val273Met was again present in homozygous state. Surprisingly, the genetic testing of newborns from southwest Bulgaria showed an even higher carrier status of about 2.6% (3/116), disproving our initial hypothesis of endogamous marriages (traditionally common in this subpopulation) being the cause of the disease in these patients. However the probability of consanguineous marriages being the cause for further exaggeration of the anyway very high carrier frequency cannot be excluded.
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Affiliation(s)
- Savina Tincheva
- Department of Medical Chemistry and Biochemistry, Medical University Sofia, 2 Zdrave Str., Sofia, Bulgaria; Genetic Medico-Diagnostic Laboratory "Genica", 90 Tsar Asen Str., Sofia, Bulgaria.
| | - Bilyana Georgieva
- Department of Medical Chemistry and Biochemistry, Medical University Sofia, 2 Zdrave Str., Sofia, Bulgaria
| | - Tihomir Todorov
- Genetic Medico-Diagnostic Laboratory "Genica", 90 Tsar Asen Str., Sofia, Bulgaria
| | - Alexey Savov
- Department of Obstetrics and Gynecology, Faculty of Medicine, National Genetic Laboratory, Medical University Sofia, 2 Zdrave Str., Sofia, Bulgaria
| | - Slavena Tsaneva
- Genetic Medico-Diagnostic Laboratory "Genica", 90 Tsar Asen Str., Sofia, Bulgaria
| | - Ivan Litvinenko
- Department of Neurology, University Pediatric Hospital, Medical University, 11 Acad. Ivan Evstatiev Geshov Str., Sofia, Bulgaria
| | - Vanyo Mitev
- Department of Medical Chemistry and Biochemistry, Medical University Sofia, 2 Zdrave Str., Sofia, Bulgaria
| | - Albena Todorova
- Department of Medical Chemistry and Biochemistry, Medical University Sofia, 2 Zdrave Str., Sofia, Bulgaria; Genetic Medico-Diagnostic Laboratory "Genica", 90 Tsar Asen Str., Sofia, Bulgaria
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Imbrici P, Altamura C, Camerino GM, Mangiatordi GF, Conte E, Maggi L, Brugnoni R, Musaraj K, Caloiero R, Alberga D, Marsano RM, Ricci G, Siciliano G, Nicolotti O, Mora M, Bernasconi P, Desaphy JF, Mantegazza R, Camerino DC. Multidisciplinary study of a new ClC-1 mutation causing myotonia congenita: a paradigm to understand and treat ion channelopathies. FASEB J 2016; 30:3285-3295. [PMID: 27324117 PMCID: PMC5024700 DOI: 10.1096/fj.201500079r] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 06/07/2016] [Indexed: 11/11/2022]
Abstract
Myotonia congenita is an inherited disease that is characterized by impaired muscle relaxation after contraction caused by loss-of-function mutations in the skeletal muscle ClC-1 channel. We report a novel ClC-1 mutation, T335N, that is associated with a mild phenotype in 1 patient, located in the extracellular I-J loop. The purpose of this study was to provide a solid correlation between T335N dysfunction and clinical symptoms in the affected patient as well as to offer hints for drug development. Our multidisciplinary approach includes patch-clamp electrophysiology on T335N and ClC-1 wild-type channels expressed in tsA201 cells, Western blot and quantitative PCR analyses on muscle biopsies from patient and unaffected individuals, and molecular dynamics simulations using a homology model of the ClC-1 dimer. T335N channels display reduced chloride currents as a result of gating alterations rather than altered surface expression. Molecular dynamics simulations suggest that the I-J loop might be involved in conformational changes that occur at the dimer interface, thus affecting gating. Finally, the gene expression profile of T335N carrier showed a diverse expression of K+ channel genes, compared with control individuals, as potentially contributing to the phenotype. This experimental paradigm satisfactorily explained myotonia in the patient. Furthermore, it could be relevant to the study and therapy of any channelopathy.-Imbrici, P., Altamura, C., Camerino, G. M., Mangiatordi, G. F., Conte, E., Maggi, L., Brugnoni, R., Musaraj, K., Caloiero, R., Alberga, D., Marsano, R. M., Ricci, G., Siciliano, G., Nicolotti, O., Mora, M., Bernasconi, P., Desaphy, J.-F., Mantegazza, R., Camerino, D. C. Multidisciplinary study of a new ClC-1 mutation causing myotonia congenita: a paradigm to understand and treat ion channelopathies.
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Affiliation(s)
- Paola Imbrici
- Department of Pharmacy, Drug Sciences, University of Bari "Aldo Moro," Bari, Italy; paola.imbrici@uniba
| | - Concetta Altamura
- Department of Pharmacy, Drug Sciences, University of Bari "Aldo Moro," Bari, Italy
| | | | | | - Elena Conte
- Department of Pharmacy, Drug Sciences, University of Bari "Aldo Moro," Bari, Italy
| | - Lorenzo Maggi
- Division of Neurology, Neuroimmunology and Neuromuscular Diseases Unit, Istituti di Ricovero e Cura a Carattere Scientifico Fondazione Istituto Neurologico "Carlo Besta," Milan, Italy
| | - Raffaella Brugnoni
- Division of Neurology, Neuroimmunology and Neuromuscular Diseases Unit, Istituti di Ricovero e Cura a Carattere Scientifico Fondazione Istituto Neurologico "Carlo Besta," Milan, Italy
| | - Kejla Musaraj
- Department of Pharmacy, Drug Sciences, University of Bari "Aldo Moro," Bari, Italy
| | - Roberta Caloiero
- Department of Pharmacy, Drug Sciences, University of Bari "Aldo Moro," Bari, Italy
| | - Domenico Alberga
- Department of Physics "M. Merlin," Istituto Nazionale di Fisica Nucleare and Centro di Tecnologie Innovative per la Rilevazione e l'Elaborazione del Segnale, University of Bari "Aldo Moro," Bari, Italy
| | | | - Giulia Ricci
- Department of Clinical and Experimental Medicine, Section of Neurology, University of Pisa, Pisa, Italy
| | - Gabriele Siciliano
- Department of Clinical and Experimental Medicine, Section of Neurology, University of Pisa, Pisa, Italy
| | - Orazio Nicolotti
- Department of Pharmacy, Drug Sciences, University of Bari "Aldo Moro," Bari, Italy
| | - Marina Mora
- Division of Neurology, Neuroimmunology and Neuromuscular Diseases Unit, Istituti di Ricovero e Cura a Carattere Scientifico Fondazione Istituto Neurologico "Carlo Besta," Milan, Italy
| | - Pia Bernasconi
- Division of Neurology, Neuroimmunology and Neuromuscular Diseases Unit, Istituti di Ricovero e Cura a Carattere Scientifico Fondazione Istituto Neurologico "Carlo Besta," Milan, Italy
| | - Jean-Francois Desaphy
- Department of Biomedical Sciences and Human Oncology, University of Bari "Aldo Moro," Bari, Italy
| | - Renato Mantegazza
- Division of Neurology, Neuroimmunology and Neuromuscular Diseases Unit, Istituti di Ricovero e Cura a Carattere Scientifico Fondazione Istituto Neurologico "Carlo Besta," Milan, Italy
| | - Diana Conte Camerino
- Department of Pharmacy, Drug Sciences, University of Bari "Aldo Moro," Bari, Italy
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Vindas-Smith R, Fiore M, Vásquez M, Cuenca P, del Valle G, Lagostena L, Gaitán-Peñas H, Estevez R, Pusch M, Morales F. Identification and Functional Characterization ofCLCN1Mutations Found in Nondystrophic Myotonia Patients. Hum Mutat 2015; 37:74-83. [DOI: 10.1002/humu.22916] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 09/25/2015] [Indexed: 10/22/2022]
Affiliation(s)
- Rebeca Vindas-Smith
- Instituto de Investigaciones en Salud (INISA); Universidad de Costa Rica; San José Costa Rica
| | - Michele Fiore
- Istituto di Biofisica; CNR; Via De Marini 6 Genova Italy
| | - Melissa Vásquez
- Instituto de Investigaciones en Salud (INISA); Universidad de Costa Rica; San José Costa Rica
- Centro de Investigación en Neurociencias (CIN); Universidad de Costa Rica; San José Costa Rica
| | - Patricia Cuenca
- Instituto de Investigaciones en Salud (INISA); Universidad de Costa Rica; San José Costa Rica
- Centro de Investigación en Neurociencias (CIN); Universidad de Costa Rica; San José Costa Rica
- Escuela de Medicina; Universidad de Costa Rica; Curridabat San José Costa Rica
| | - Gerardo del Valle
- Laboratorio de Neurofisiología (Neurolab); Curridabat San José Costa Rica
| | | | - Héctor Gaitán-Peñas
- Departament de Ciències Fisiològiques II; Unitat de Fisiologia; Universitat de Barcelona; Carrer Feixa Llarga s/n, L'Hospitalet de Llobregat Barcelona Spain
- U-750, Centro de Investigación en red de enfermedades raras (CIBERER); ISCIII; Barcelona Spain
| | - Raúl Estevez
- Departament de Ciències Fisiològiques II; Unitat de Fisiologia; Universitat de Barcelona; Carrer Feixa Llarga s/n, L'Hospitalet de Llobregat Barcelona Spain
- U-750, Centro de Investigación en red de enfermedades raras (CIBERER); ISCIII; Barcelona Spain
| | - Michael Pusch
- Istituto di Biofisica; CNR; Via De Marini 6 Genova Italy
| | - Fernando Morales
- Instituto de Investigaciones en Salud (INISA); Universidad de Costa Rica; San José Costa Rica
- Centro de Investigación en Neurociencias (CIN); Universidad de Costa Rica; San José Costa Rica
- Escuela de Medicina; Universidad de Costa Rica; Curridabat San José Costa Rica
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Impaired surface membrane insertion of homo- and heterodimeric human muscle chloride channels carrying amino-terminal myotonia-causing mutations. Sci Rep 2015; 5:15382. [PMID: 26502825 PMCID: PMC4621517 DOI: 10.1038/srep15382] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 09/23/2015] [Indexed: 12/03/2022] Open
Abstract
Mutations in the muscle chloride channel gene (CLCN1) cause myotonia congenita, an inherited condition characterized by muscle stiffness upon sudden forceful movement. We here studied the functional consequences of four disease-causing mutations that predict amino acid substitutions Q43R, S70L, Y137D and Q160H. Wild-type (WT) and mutant hClC-1 channels were heterologously expressed as YFP or CFP fusion protein in HEK293T cells and analyzed by whole-cell patch clamp and fluorescence recordings on individual cells. Q43R, Y137D and Q160H, but not S70L reduced macroscopic current amplitudes, but left channel gating and unitary current amplitudes unaffected. We developed a novel assay combining electrophysiological and fluorescence measurements at the single-cell level in order to measure the probability of ion channel surface membrane insertion. With the exception of S70L, all tested mutations significantly reduced the relative number of homodimeric hClC-1 channels in the surface membrane. The strongest effect was seen for Q43R that reduced the surface insertion probability by more than 99% in Q43R homodimeric channels and by 92 ± 3% in heterodimeric WT/Q43R channels compared to homodimeric WT channels. The new method offers a sensitive approach to investigate mutations that were reported to cause channelopathies, but display only minor changes in ion channel function.
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Liu XL, Huang XJ, Shen JY, Zhou HY, Luan XH, Wang T, Chen SD, Wang Y, Tang HD, Cao L. Myotonia congenita: novel mutations in CLCN1 gene. Channels (Austin) 2015; 9:292-8. [PMID: 26260254 DOI: 10.1080/19336950.2015.1075676] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Myotonia congenita belongs to the group of non-dystrophic myotonia caused by mutations of CLCN1gene, which encodes human skeletal muscle chloride channel 1. It can be inherited either in autosomal dominant (Thomsen disease) or recessive (Becker disease) forms. Here we have sequenced all 23 exons and exon-intron boundaries of the CLCN1 gene, in a panel of 5 unrelated Chinese patients with myotonia congenita (2 with dominant and 3 with recessive form). In addition, detailed clinical analysis was performed in these patients to summarize their clinical characteristics in relation to their genotypes. Mutational analyses revealed 7 different point mutations. Of these, we have found 3 novel mutations including 2 missense (R47W, V229M), one splicing (IVS19+2T>C), and 4 known mutations (Y261C,G523D, M560T, G859D). Our data expand the spectrum of CLCN1 mutations and provide insights for genotype-phenotype correlations of myotonia congenita in the Chinese population.
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Affiliation(s)
- Xiao-Li Liu
- a Department of Neurology ; Rui Jin Hospital and Rui Jin Hospital North, Shanghai Jiao Tong University School of Medicine ; Shanghai , China
| | - Xiao-Jun Huang
- a Department of Neurology ; Rui Jin Hospital and Rui Jin Hospital North, Shanghai Jiao Tong University School of Medicine ; Shanghai , China
| | - Jun-Yi Shen
- a Department of Neurology ; Rui Jin Hospital and Rui Jin Hospital North, Shanghai Jiao Tong University School of Medicine ; Shanghai , China
| | - Hai-Yan Zhou
- a Department of Neurology ; Rui Jin Hospital and Rui Jin Hospital North, Shanghai Jiao Tong University School of Medicine ; Shanghai , China
| | - Xing-Hua Luan
- a Department of Neurology ; Rui Jin Hospital and Rui Jin Hospital North, Shanghai Jiao Tong University School of Medicine ; Shanghai , China
| | - Tian Wang
- a Department of Neurology ; Rui Jin Hospital and Rui Jin Hospital North, Shanghai Jiao Tong University School of Medicine ; Shanghai , China
| | - Sheng-Di Chen
- a Department of Neurology ; Rui Jin Hospital and Rui Jin Hospital North, Shanghai Jiao Tong University School of Medicine ; Shanghai , China
| | - Ying Wang
- a Department of Neurology ; Rui Jin Hospital and Rui Jin Hospital North, Shanghai Jiao Tong University School of Medicine ; Shanghai , China
| | - Hui-Dong Tang
- a Department of Neurology ; Rui Jin Hospital and Rui Jin Hospital North, Shanghai Jiao Tong University School of Medicine ; Shanghai , China
| | - Li Cao
- a Department of Neurology ; Rui Jin Hospital and Rui Jin Hospital North, Shanghai Jiao Tong University School of Medicine ; Shanghai , China
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Imbrici P, Maggi L, Mangiatordi GF, Dinardo MM, Altamura C, Brugnoni R, Alberga D, Pinter GL, Ricci G, Siciliano G, Micheli R, Annicchiarico G, Lattanzi G, Nicolotti O, Morandi L, Bernasconi P, Desaphy JF, Mantegazza R, Camerino DC. ClC-1 mutations in myotonia congenita patients: insights into molecular gating mechanisms and genotype-phenotype correlation. J Physiol 2015; 593:4181-99. [PMID: 26096614 DOI: 10.1113/jp270358] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 06/04/2015] [Indexed: 12/31/2022] Open
Abstract
KEY POINTS Loss-of-function mutations of the skeletal muscle ClC-1 channel cause myotonia congenita with variable phenotypes. Using patch clamp we show that F484L, located in the conducting pore, probably induces mild dominant myotonia by right-shifting the slow gating of ClC-1 channel, without exerting a dominant-negative effect on the wild-type (WT) subunit. Molecular dynamics simulations suggest that F484L affects the slow gate by increasing the frequency and the stability of H-bond formation between E232 in helix F and Y578 in helix R. Three other myotonic ClC-1 mutations are shown to produce distinct effects on channel function: L198P shifts the slow gate to positive potentials, V640G reduces channel activity, while L628P displays a WT-like behaviour (electrophysiology data only). Our results provide novel insight into the molecular mechanisms underlying normal and altered ClC-1 function. ABSTRACT Myotonia congenita is an inherited disease caused by loss-of-function mutations of the skeletal muscle ClC-1 chloride channel, characterized by impaired muscle relaxation after contraction and stiffness. In the present study, we provided an in-depth characterization of F484L, a mutation previously identified in dominant myotonia, in order to define the genotype-phenotype correlation, and to elucidate the contribution of this pore residue to the mechanisms of ClC-1 gating. Patch-clamp recordings showed that F484L reduced chloride currents at every tested potential and dramatically right-shifted the voltage dependence of slow gating, thus contributing to the mild clinical phenotype of affected heterozygote carriers. Unlike dominant mutations located at the dimer interface, no dominant-negative effect was observed when F484L mutant subunits were co-expressed with wild type. Molecular dynamics simulations further revealed that F484L affected the slow gate by increasing the frequency and stability of the H-bond formation between the pore residue E232 and the R helix residue Y578. In addition, using patch-clamp electrophysiology, we characterized three other myotonic ClC-1 mutations. We proved that the dominant L198P mutation in the channel pore also right-shifted the voltage dependence of slow gating, recapitulating mild myotonia. The recessive V640G mutant drastically reduced channel function, which probably accounts for myotonia. In contrast, the recessive L628P mutant produced currents very similar to wild type, suggesting that the occurrence of the compound truncating mutation (Q812X) or other muscle-specific mechanisms accounted for the severe symptoms observed in this family. Our results provide novel insight into the molecular mechanisms underlying normal and altered ClC-1 function.
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Affiliation(s)
- P Imbrici
- Department of Pharmacy - Drug Sciences, University of Bari, Bari, Italy
| | - L Maggi
- Neuroimmunology and Neuromuscular Diseases Unit, IRCCS Fondazione Istituto Neurologico 'Carlo Besta', Milano, Italy
| | - G F Mangiatordi
- Department of Pharmacy - Drug Sciences, University of Bari, Bari, Italy
| | - M M Dinardo
- Department of Pharmacy - Drug Sciences, University of Bari, Bari, Italy
| | - C Altamura
- Department of Pharmacy - Drug Sciences, University of Bari, Bari, Italy
| | - R Brugnoni
- Neuroimmunology and Neuromuscular Diseases Unit, IRCCS Fondazione Istituto Neurologico 'Carlo Besta', Milano, Italy
| | - D Alberga
- Department of Physics 'M. Merlin', INFN and TIRES, University of Bari, Bari, Italy
| | - G Lauria Pinter
- Neuroalgology and Headache Unit, IRCCS Fondazione Istituto Neurologico 'Carlo Besta', Milano, Italy
| | - G Ricci
- Department of Clinical and Experimental Medicine, Section of Neurology, University of Pisa, Pisa, Italy
| | - G Siciliano
- Department of Clinical and Experimental Medicine, Section of Neurology, University of Pisa, Pisa, Italy
| | - R Micheli
- Unit of Child Neurology and Psychiatry, Spedali Civili, Brescia, Italy
| | - G Annicchiarico
- Regional Coordination for Rare Diseases, A. Re. S. Puglia, Bari, Italy
| | - G Lattanzi
- Department of Physics 'M. Merlin', INFN and TIRES, University of Bari, Bari, Italy
| | - O Nicolotti
- Department of Pharmacy - Drug Sciences, University of Bari, Bari, Italy
| | - L Morandi
- Neuroimmunology and Neuromuscular Diseases Unit, IRCCS Fondazione Istituto Neurologico 'Carlo Besta', Milano, Italy
| | - P Bernasconi
- Neuroimmunology and Neuromuscular Diseases Unit, IRCCS Fondazione Istituto Neurologico 'Carlo Besta', Milano, Italy
| | - J-F Desaphy
- Department of Pharmacy - Drug Sciences, University of Bari, Bari, Italy
| | - R Mantegazza
- Neuroimmunology and Neuromuscular Diseases Unit, IRCCS Fondazione Istituto Neurologico 'Carlo Besta', Milano, Italy
| | - D Conte Camerino
- Department of Pharmacy - Drug Sciences, University of Bari, Bari, Italy
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Clinical, Molecular, and Functional Characterization of CLCN1 Mutations in Three Families with Recessive Myotonia Congenita. Neuromolecular Med 2015; 17:285-96. [PMID: 26007199 PMCID: PMC4534513 DOI: 10.1007/s12017-015-8356-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Accepted: 05/07/2015] [Indexed: 01/08/2023]
Abstract
Myotonia congenita (MC) is an inherited muscle disease characterized by impaired muscle relaxation after contraction, resulting in muscle stiffness. Both recessive (Becker’s disease) or dominant (Thomsen’s disease) MC are caused by mutations in the CLCN1 gene encoding the voltage-dependent chloride ClC-1 channel, which is quite exclusively expressed in skeletal muscle. More than 200 CLCN1 mutations have been associated with MC. We provide herein a detailed clinical, molecular, and functional evaluation of four patients with recessive MC belonging to three different families. Four CLCN1 variants were identified, three of which have never been characterized. The c.244A>G (p.T82A) and c.1357C>T (p.R453W) variants were each associated in compound heterozygosity with c.568GG>TC (p.G190S), for which pathogenicity is already known. The new c.809G>T (p.G270V) variant was found in the homozygous state. Patch-clamp studies of ClC-1 mutants expressed in tsA201 cells confirmed the pathogenicity of p.G270V, which greatly shifts the voltage dependence of channel activation toward positive potentials. Conversely, the mechanisms by which p.T82A and p.R453W cause the disease remained elusive, as the mutated channels behave similarly to WT. The results also suggest that p.G190S does not exert dominant-negative effects on other mutated ClC-1 subunits. Moreover, we performed a RT-PCR quantification of selected ion channels transcripts in muscle biopsies of two patients. The results suggest gene expression alteration of sodium and potassium channel subunits in myotonic muscles; if confirmed, such analysis may pave the way toward a better understanding of disease phenotype and a possible identification of new therapeutic options.
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Imbrici P, Altamura C, Pessia M, Mantegazza R, Desaphy JF, Camerino DC. ClC-1 chloride channels: state-of-the-art research and future challenges. Front Cell Neurosci 2015; 9:156. [PMID: 25964741 PMCID: PMC4410605 DOI: 10.3389/fncel.2015.00156] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 04/08/2015] [Indexed: 01/06/2023] Open
Abstract
The voltage-dependent ClC-1 chloride channel belongs to the CLC channel/transporter family. It is a homodimer comprising two individual pores which can operate independently or simultaneously according to two gating modes, the fast and the slow gate of the channel. ClC-1 is preferentially expressed in the skeletal muscle fibers where the presence of an efficient Cl(-) homeostasis is crucial for the correct membrane repolarization and propagation of action potential. As a consequence, mutations in the CLCN1 gene cause dominant and recessive forms of myotonia congenita (MC), a rare skeletal muscle channelopathy caused by abnormal membrane excitation, and clinically characterized by muscle stiffness and various degrees of transitory weakness. Elucidation of the mechanistic link between the genetic defects and the disease pathogenesis is still incomplete and, at this time, there is no specific treatment for MC. Still controversial is the subcellular localization pattern of ClC-1 channels in skeletal muscle as well as its modulation by some intracellular factors. The expression of ClC-1 in other tissues such as in brain and heart and the possible assembly of ClC-1/ClC-2 heterodimers further expand the physiological properties of ClC-1 and its involvement in diseases. A recent de novo CLCN1 truncation mutation in a patient with generalized epilepsy indeed postulates an unexpected role of this channel in the control of neuronal network excitability. This review summarizes the most relevant and state-of-the-art research on ClC-1 chloride channels physiology and associated diseases.
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Affiliation(s)
- Paola Imbrici
- Department of Pharmacy - Drug Sciences, University of Bari “Aldo Moro”,Bari, Italy
| | - Concetta Altamura
- Department of Pharmacy - Drug Sciences, University of Bari “Aldo Moro”,Bari, Italy
| | - Mauro Pessia
- Department of Pharmacy - Drug Sciences, University of Bari “Aldo Moro”,Bari, Italy
| | - Renato Mantegazza
- Department of Pharmacy - Drug Sciences, University of Bari “Aldo Moro”,Bari, Italy
| | | | - Diana Conte Camerino
- Department of Pharmacy - Drug Sciences, University of Bari “Aldo Moro”,Bari, Italy
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Ardissone A, Brugnoni R, Gandioli C, Milani M, Ciano C, Uziel G, Moroni I. Double-trouble in pediatric neurology: myotonia congenita combined with charcot-marie-tooth disease type 1a. Muscle Nerve 2014; 50:145-7. [PMID: 24515601 DOI: 10.1002/mus.24205] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Revised: 02/06/2014] [Accepted: 02/07/2014] [Indexed: 11/06/2022]
Affiliation(s)
- Anna Ardissone
- Child Neurology Unit, Foundation IRCCS "Carlo Besta" Neurological Institute, Milan, Italy
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37
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Ulzi G, Sansone VA, Magri F, Corti S, Bresolin N, Comi GP, Lucchiari S. In vitro analysis of splice site mutations in the CLCN1 gene using the minigene assay. Mol Biol Rep 2014; 41:2865-74. [PMID: 24452722 DOI: 10.1007/s11033-014-3142-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 01/11/2014] [Indexed: 12/21/2022]
Abstract
Mutations in the chloride channel gene CLCN1 cause the allelic disorders Thomsen (dominant) and Becker (recessive) myotonia congenita (MC). The encoded protein, ClC-1, is the primary channel that mediates chloride (Cl-) conductance in skeletal muscle. Mutations in CLCN1 lower the channel's threshold voltage, leading to spontaneous action potentials that are not coupled to neuromuscular transmission and resulting in myotonia. Over 120 mutations in CLCN1 have been described, 10% of which are splicing defects. Biological specimens suitable for RNA extraction are not always available, but obtaining genomic DNA for analysis is easy and non-invasive. This is the first study to evaluate the pathogenic potential of novel splicing mutations using the minigene approach, which is based on genomic DNA analysis. Splicing mutations accounted for 23% of all pathogenic variants in our cohort of MC patients. Four were heterozygous mutations in four unrelated individuals, belonging to this cohort: c.563G>T in exon 5; c.1169-5T>G in intron 10; c.1251+1G>A in intron 11, and c.1931-2A>G in intron 16. These variants were expressed in HEK 293 cells, and aberrant splicing was verified by in vitro transcription and sequencing of the cDNA. Our findings confirm the need to further investigate the nature of rearrangements associated with this class of mutations and their effects on mature transcripts. In particular, splicing mutations predicted to generate in-frame transcripts may generate out-of-frame mRNA transcripts that do not produce functional ClC-1. Clinically, incomplete molecular evaluation could lead to delayed or faulty diagnosis.
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Affiliation(s)
- Gianna Ulzi
- Neurology Unit, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), Dino Ferrari Centre, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, University of Milan, Via Sforza 35, 20122, Milan, Italy
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Skálová D, Zídková J, Voháňka S, Mazanec R, Mušová Z, Vondráček P, Mrázová L, Kraus J, Réblová K, Fajkusová L. CLCN1 mutations in Czech patients with myotonia congenita, in silico analysis of novel and known mutations in the human dimeric skeletal muscle chloride channel. PLoS One 2013; 8:e82549. [PMID: 24349310 PMCID: PMC3859631 DOI: 10.1371/journal.pone.0082549] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Accepted: 10/26/2013] [Indexed: 11/18/2022] Open
Abstract
Myotonia congenita (MC) is a genetic disease caused by mutations in the skeletal muscle chloride channel gene (CLCN1) encoding the skeletal muscle chloride channel (ClC-1). Mutations of CLCN1 result in either autosomal dominant MC (Thomsen disease) or autosomal recessive MC (Becker disease). The ClC-1 protein is a homodimer with a separate ion pore within each monomer. Mutations causing recessive myotonia most likely affect properties of only the mutant monomer in the heterodimer, leaving the wild type monomer unaffected, while mutations causing dominant myotonia affect properties of both subunits in the heterodimer. Our study addresses two points: 1) molecular genetic diagnostics of MC by analysis of the CLCN1 gene and 2) structural analysis of mutations in the homology model of the human dimeric ClC-1 protein. In the first part, 34 different types of CLCN1 mutations were identified in 51 MC probands (14 mutations were new). In the second part, on the basis of the homology model we identified the amino acids which forming the dimer interface and those which form the Cl(-) ion pathway. In the literature, we searched for mutations of these amino acids for which functional analyses were performed to assess the correlation between localisation of a mutation and occurrence of a dominant-negative effect (corresponding to dominant MC). This revealed that both types of mutations, with and without a dominant-negative effect, are localised at the dimer interface while solely mutations without a dominant-negative effect occur inside the chloride channel. This work is complemented by structural analysis of the homology model which provides elucidation of the effects of mutations, including a description of impacts of newly detected missense mutations.
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Affiliation(s)
- Daniela Skálová
- Centre of Molecular Biology and Gene Therapy, University Hospital, Brno, Brno, Czech Republic
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Jana Zídková
- Centre of Molecular Biology and Gene Therapy, University Hospital, Brno, Brno, Czech Republic
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Stanislav Voháňka
- Department of Neurology, University Hospital Brno, Brno, Czech Republic
| | - Radim Mazanec
- Department of Neurology, Charles University Second Faculty of Medicine and University Hospital Motol, Prague, Czech Republic
| | - Zuzana Mušová
- Department of Biology and Medical Genetics, Charles University Second Faculty of Medicine and University Hospital Motol, Prague, Czech Republic
| | - Petr Vondráček
- Department of Child Neurology, University Hospital Brno, Brno, Czech Republic
| | - Lenka Mrázová
- Department of Child Neurology, University Hospital Brno, Brno, Czech Republic
| | - Josef Kraus
- Department of Child Neurology, Second School of Medicine, Charles University and University Hospital Motol, Prague, Czech Republic
| | - Kamila Réblová
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
- * E-mail: (KR); (LF)
| | - Lenka Fajkusová
- Centre of Molecular Biology and Gene Therapy, University Hospital, Brno, Brno, Czech Republic
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
- * E-mail: (KR); (LF)
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Cooper DN, Krawczak M, Polychronakos C, Tyler-Smith C, Kehrer-Sawatzki H. Where genotype is not predictive of phenotype: towards an understanding of the molecular basis of reduced penetrance in human inherited disease. Hum Genet 2013; 132:1077-130. [PMID: 23820649 PMCID: PMC3778950 DOI: 10.1007/s00439-013-1331-2] [Citation(s) in RCA: 407] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Accepted: 06/15/2013] [Indexed: 02/06/2023]
Abstract
Some individuals with a particular disease-causing mutation or genotype fail to express most if not all features of the disease in question, a phenomenon that is known as 'reduced (or incomplete) penetrance'. Reduced penetrance is not uncommon; indeed, there are many known examples of 'disease-causing mutations' that fail to cause disease in at least a proportion of the individuals who carry them. Reduced penetrance may therefore explain not only why genetic diseases are occasionally transmitted through unaffected parents, but also why healthy individuals can harbour quite large numbers of potentially disadvantageous variants in their genomes without suffering any obvious ill effects. Reduced penetrance can be a function of the specific mutation(s) involved or of allele dosage. It may also result from differential allelic expression, copy number variation or the modulating influence of additional genetic variants in cis or in trans. The penetrance of some pathogenic genotypes is known to be age- and/or sex-dependent. Variable penetrance may also reflect the action of unlinked modifier genes, epigenetic changes or environmental factors. At least in some cases, complete penetrance appears to require the presence of one or more genetic variants at other loci. In this review, we summarize the evidence for reduced penetrance being a widespread phenomenon in human genetics and explore some of the molecular mechanisms that may help to explain this enigmatic characteristic of human inherited disease.
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Affiliation(s)
- David N. Cooper
- Institute of Medical Genetics, School of Medicine, Cardiff University, Heath Park, Cardiff, CF14 4XN UK
| | - Michael Krawczak
- Institute of Medical Informatics and Statistics, Christian-Albrechts University, 24105 Kiel, Germany
| | | | - Chris Tyler-Smith
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA UK
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