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Record CJ, Skorupinska M, Laura M, Rossor AM, Pareyson D, Pisciotta C, Feely SME, Lloyd TE, Horvath R, Sadjadi R, Herrmann DN, Li J, Walk D, Yum SW, Lewis RA, Day J, Burns J, Finkel RS, Saporta MA, Ramchandren S, Weiss MD, Acsadi G, Fridman V, Muntoni F, Poh R, Polke JM, Zuchner S, Shy ME, Scherer SS, Reilly MM. Genetic analysis and natural history of Charcot-Marie-Tooth disease CMTX1 due to GJB1 variants. Brain 2023; 146:4336-4349. [PMID: 37284795 PMCID: PMC10545504 DOI: 10.1093/brain/awad187] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 05/05/2023] [Accepted: 05/20/2023] [Indexed: 06/08/2023] Open
Abstract
Charcot-Marie-Tooth disease (CMT) due to GJB1 variants (CMTX1) is the second most common form of CMT. It is an X-linked disorder characterized by progressive sensory and motor neuropathy with males affected more severely than females. Many reported GJB1 variants remain classified as variants of uncertain significance (VUS). In this large, international, multicentre study we prospectively collected demographic, clinical and genetic data on patients with CMT associated with GJB1 variants. Pathogenicity for each variant was defined using adapted American College of Medical Genetics criteria. Baseline and longitudinal analyses were conducted to study genotype-phenotype correlations, to calculate longitudinal change using the CMT Examination Score (CMTES), to compare males versus females, and pathogenic/likely pathogenic (P/LP) variants versus VUS. We present 387 patients from 295 families harbouring 154 variants in GJB1. Of these, 319 patients (82.4%) were deemed to have P/LP variants, 65 had VUS (16.8%) and three benign variants (0.8%; excluded from analysis); an increased proportion of patients with P/LP variants compared with using ClinVar's classification (74.6%). Male patients (166/319, 52.0%, P/LP only) were more severely affected at baseline. Baseline measures in patients with P/LP variants and VUS showed no significant differences, and regression analysis suggested the disease groups were near identical at baseline. Genotype-phenotype analysis suggested c.-17G>A produces the most severe phenotype of the five most common variants, and missense variants in the intracellular domain are less severe than other domains. Progression of disease was seen with increasing CMTES over time up to 8 years follow-up. Standard response mean (SRM), a measure of outcome responsiveness, peaked at 3 years with moderate responsiveness [change in CMTES (ΔCMTES) = 1.3 ± 2.6, P = 0.00016, SRM = 0.50]. Males and females progressed similarly up to 8 years, but baseline regression analysis suggested that over a longer period, females progress more slowly. Progression was most pronounced for mild phenotypes (CMTES = 0-7; 3-year ΔCMTES = 2.3 ± 2.5, P = 0.001, SRM = 0.90). Enhanced variant interpretation has yielded an increased proportion of GJB1 variants classified as P/LP and will aid future variant interpretation in this gene. Baseline and longitudinal analysis of this large cohort of CMTX1 patients describes the natural history of the disease including the rate of progression; CMTES showed moderate responsiveness for the whole group at 3 years and higher responsiveness for the mild group at 3, 4 and 5 years. These results have implications for patient selection for upcoming clinical trials.
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Affiliation(s)
- Christopher J Record
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, WC1N 3BG, UK
| | - Mariola Skorupinska
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, WC1N 3BG, UK
| | - Matilde Laura
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, WC1N 3BG, UK
| | - Alexander M Rossor
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, WC1N 3BG, UK
| | - Davide Pareyson
- Department of Clinical Neurosciences, Fondazione IRCCS Istituto Neurologico Carlo Besta, 20133 Milan, Italy
| | - Chiara Pisciotta
- Department of Clinical Neurosciences, Fondazione IRCCS Istituto Neurologico Carlo Besta, 20133 Milan, Italy
| | - Shawna M E Feely
- Department of Neurology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Thomas E Lloyd
- Departments of Neurology and Neuroscience, John Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Rita Horvath
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 0PY, UK
| | - Reza Sadjadi
- Department of Neurology, Massachusetts General Hospital, Boston, MA 02114, USA
| | - David N Herrmann
- Department of Neurology, University of Rochester, Rochester, NY 14618, USA
| | - Jun Li
- Department of Neurology, Houston Methodist Hospital, Houston, TX 77030, USA
| | - David Walk
- Department of Neurology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Sabrina W Yum
- Department of Neurology, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Richard A Lewis
- Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - John Day
- Department of Neurology, Stanford University, Stanford, CA 94304, USA
| | - Joshua Burns
- University of Sydney School of Health Sciences, Faculty of Medicine and Health; Paediatric Gait Analysis Service of New South Wales, Sydney Children’s Hospitals Network, Sydney, 2145Australia
| | - Richard S Finkel
- Department of Neurology, Nemours Children’s Hospital, Orlando, FL 32827, USA
| | - Mario A Saporta
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Sindhu Ramchandren
- Department of Neurology, Wayne State University, Detroit, MI 48201, USA
- The Janssen Pharmaceutical Companies of Johnson & Johnson, Titusville, NJ 08560, USA
| | - Michael D Weiss
- Department of Neurology, University of Washington, Seattle, WA, 98195USA
| | - Gyula Acsadi
- Connecticut Children’s Medical Center, Hartford, CT 06106, USA
| | - Vera Fridman
- Department of Neurology, University of Colorado Denver School of Medicine, Aurora, CO 80045, USA
| | - Francesco Muntoni
- The Dubowitz Neuromuscular Centre, NIHR Great Ormond Street Hospital Biomedical Research Centre, Great Ormond Street Institute of Child Health University College London, and Great Ormond Street Hospital Trust, London, WC1N 1EH, UK
| | - Roy Poh
- Neurogenetics Laboratory, National Hospital for Neurology and Neurosurgery, London, WC1N 3BG, UK
| | - James M Polke
- Neurogenetics Laboratory, National Hospital for Neurology and Neurosurgery, London, WC1N 3BG, UK
| | - Stephan Zuchner
- Dr. John T. Macdonald Foundation Department of Human Genetics and John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Michael E Shy
- Department of Neurology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Steven S Scherer
- Department of Neurology, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Mary M Reilly
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, WC1N 3BG, UK
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Barbat du Closel L, Bonello-Palot N, Péréon Y, Echaniz-Laguna A, Camdessanche JP, Nadaj-Pakleza A, Chanson JB, Frachet S, Magy L, Cassereau J, Cintas P, Choumert A, Devic P, Leonard Louis S, Gravier Dumonceau R, Delmont E, Salort-Campana E, Bouhour F, Latour P, Stojkovic T, Attarian S. Clinical and electrophysiological characteristics of women with X-linked Charcot-Marie-Tooth disease. Eur J Neurol 2023; 30:3265-3276. [PMID: 37335503 DOI: 10.1111/ene.15937] [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: 01/24/2023] [Revised: 06/07/2023] [Accepted: 06/15/2023] [Indexed: 06/21/2023]
Abstract
BACKGROUND X-Linked Charcot-Marie-Tooth disease type 1 (CMTX1) is characterized by gender differences in clinical severity. Women are usually clinically affected later and less severely than men. However, their clinical presentation appears to be heterogenous. Our aim was to extend the phenotypic description in a large series of women with CMTX1. METHODS We retrospectively evaluated 263 patients with CMTX1 from 11 French reference centers. Demographic, clinical, and nerve conduction data were collected. The severity was assessed by CMT Examination Score (CMTES) and Overall Neuropathy Limitations Scale (ONLS) scores. We looked for asymmetrical strength, heterogeneous motor nerve conduction velocity (MNCV), and motor conduction blocks (CB). RESULTS The study included 137 women and 126 men from 151 families. Women had significantly more asymmetric motor deficits and MNCV than men. Women with an age of onset after 19 years were milder. Two groups of women were identified after 48 years of age. The first group represented 55%, with women progressing as severely as men, however, with a later onset age. The second group had mild or no symptoms. Some 39% of women had motor CB. Four women received intravenous immunoglobulin before being diagnosed with CMTX1. CONCLUSIONS We identified two subgroups of women with CMTX1 who were over 48 years of age. Additionally, we have demonstrated that women with CMTX can exhibit an atypical clinical presentation, which may result in misdiagnosis. Therefore, in women presenting with chronic neuropathy, the presence of clinical asymmetry, heterogeneous MNCV, and/or motor CB should raise suspicion for X-linked CMT, particularly CMTX1, and be included in the differential diagnosis.
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Affiliation(s)
- Luce Barbat du Closel
- Reference Center for Neuromuscular Disorders and ALS, APHM, CHU La Timone, Marseille, France
| | | | - Yann Péréon
- CHU Nantes, Laboratoire d'Explorations Fonctionnelles, Reference Center for NMD AOC, Filnemus, Euro-NMD, Nantes, France
| | - Andoni Echaniz-Laguna
- Department of Neurology, APHP, CHU de Bicêtre, Le Kremlin-Bicêtre, France
- French National Reference Center for Rare Neuropathies, Le Kremlin-Bicêtre, France
- Inserm U1195 and Paris-Saclay University, Le Kremlin-Bicêtre, France
| | | | - Aleksandra Nadaj-Pakleza
- Centre de Référence des maladies Neuromusculaires Nord/Est/Ile-de-France, Service de Neurologie, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Jean-Baptiste Chanson
- Centre de Référence des maladies Neuromusculaires Nord/Est/Ile-de-France, Service de Neurologie, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Simon Frachet
- Service et Laboratoire de Neurologie, Centre de Référence Neuropathies Périphériques rares (NNERF), UR, Limoges, France
| | - Laurent Magy
- Service et Laboratoire de Neurologie, Centre de Référence Neuropathies Périphériques rares (NNERF), UR, Limoges, France
| | - Julien Cassereau
- Reference Center for Neuromuscular Disorders AOC and National Reference Center for Neurogenetic Diseases, Angers University Hospital, Angers, France
| | - Pascal Cintas
- Centre de référence de pathologie neuromusculaire de ToulouseHôpital Purpan, Toulouse, France
| | - Ariane Choumert
- Service des Maladies Neurologiques Rares, CHU de la Réunion, Saint-Pierre, France
| | - Perrine Devic
- Department of Neurology, Hospices Civils de Lyon, Lyon Sud Hospital, Pierre-Bénite, France
| | | | - Robinson Gravier Dumonceau
- APHM, Hop Timone, BioSTIC, Biostatistique et Technologies de l'Information et de la Communication, Marseille, France
| | - Emilien Delmont
- Reference Center for Neuromuscular Disorders and ALS, APHM, CHU La Timone, Marseille, France
| | - Emmanuelle Salort-Campana
- Reference Center for Neuromuscular Disorders and ALS, APHM, CHU La Timone, Marseille, France
- Marseille Medical Genetics, Aix-Marseille University-Inserm UMR 1251, Marseille, France
| | - Françoise Bouhour
- Service d'Electroneuromyographie et Pathologies Neuromusculaires, Hospices Civils de Lyon, Lyon, France
| | - Philippe Latour
- PGNM, Institut NeuroMyoGène, Université Lyon1-CNRS UMR5261-INSERM U1315, Lyon, France
- Unité fonctionnelle de Neurogénétique Moléculaire, CHU de Lyon-HCL groupement Est, Bron, France
| | - Tanya Stojkovic
- Institut de Myologie, Hôpital Pitié-Salpêtrière, Paris, France
| | - Shahram Attarian
- Reference Center for Neuromuscular Disorders and ALS, APHM, CHU La Timone, Marseille, France
- Marseille Medical Genetics, Aix-Marseille University-Inserm UMR 1251, Marseille, France
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Tadenev ALD, Hatton CL, Pattavina B, Mullins T, Schneider R, Bogdanik LP, Burgess RW. Two new mouse models of Gjb1-associated Charcot-Marie-Tooth disease type 1X. J Peripher Nerv Syst 2023; 28:317-328. [PMID: 37551045 DOI: 10.1111/jns.12588] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 07/25/2023] [Accepted: 08/04/2023] [Indexed: 08/09/2023]
Abstract
BACKGROUND Charcot-Marie-Tooth disease type 1X is caused by mutations in GJB1, which is the second most common gene associated with inherited peripheral neuropathy. The GJB1 gene encodes connexin 32 (CX32), a gap junction protein expressed in myelinating glial cells. The gene is X-linked, and the mutations cause a loss of function. AIMS A large number of disease-associated variants have been identified, and many result in mistrafficking and mislocalization of the protein. An existing knockout mouse lacking Gjb1 expression provides a valid animal model of CMT1X, but the complete lack of protein may not fully recapitulate the disease mechanisms caused by aberrant CX32 proteins. To better represent the spectrum of human CMT1X-associated mutations, we have generated a new Gjb1 knockin mouse model. METHODS CRISPR/Cas9 genome editing was used to produce mice carrying the R15Q mutation in Gjb1. In addition, we identified a second allele with an early frame shift mutation in codon 7 (del2). Mice were analyzed using clinically relevant molecular, histological, neurophysiological, and behavioral assays. RESULTS Both alleles produce protein detectable by immunofluorescence in Schwann cells, with some protein properly localizing to nodes of Ranvier. However, both alleles also result in peripheral neuropathy with thinly myelinated and demyelinated axons, as well as degenerating and regenerating axons, predominantly in distal motor nerves. Nerve conduction velocities were only mildly reduced at later ages and compound muscle action potential amplitudes were not reduced. Levels of neurofilament light chain in plasma were elevated in both alleles. The del2 mice have an onset at ~3 months of age, whereas the R15Q mice had a later onset at 5-6 months of age, suggesting a milder loss of function. Both alleles performed comparably to wild type littermates in accelerating rotarod and grip strength tests of neuromuscular performance. INTERPRETATION We have generated and characterized two new mouse models of CMT1X that will be useful for future mechanistic and preclinical studies.
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Affiliation(s)
| | - C L Hatton
- The Jackson Laboratory, Bar Harbor, Maine, USA
| | - B Pattavina
- The Jackson Laboratory, Bar Harbor, Maine, USA
| | - T Mullins
- The Jackson Laboratory, Bar Harbor, Maine, USA
| | - R Schneider
- The Jackson Laboratory, Bar Harbor, Maine, USA
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Zaman Q, Khan MA, Sahar K, Rehman G, Khan H, Rehman M, Najumuddin, Ahmad I, Tariq M, Muthaffar OY, Abdulkareem AA, Bibi F, Naseer MI, Faisal MS, Wasif N, Jelani M. Novel Variants in MPV17, PRX, GJB1, and SACS Cause Charcot-Marie-Tooth and Spastic Ataxia of Charlevoix-Saguenay Type Diseases. Genes (Basel) 2023; 14:328. [PMID: 36833258 PMCID: PMC9956329 DOI: 10.3390/genes14020328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 01/22/2023] [Accepted: 01/25/2023] [Indexed: 01/31/2023] Open
Abstract
Charcot-Marie-Tooth disease (CMT) and autosomal recessive spastic ataxia of Charlevoix-Saguenay type (ARSACS) are large heterogeneous groups of sensory, neurological genetic disorders characterized by sensory neuropathies, muscular atrophies, abnormal sensory conduction velocities, and ataxia. CMT2EE (OMIM: 618400) is caused by mutations in MPV17 (OMIM: 137960), CMT4F (OMIM: 614895) is caused by PRX (OMIM: 605725), CMTX1 (OMIM: 302800) is caused by mutations in GJB1 (OMIM: 304040), and ARSACS (OMIM: 270550) is caused by mutations in SACS (OMIM: 604490). In this study, we enrolled four families: DG-01, BD-06, MR-01, and ICP-RD11, with 16 affected individuals, for clinical and molecular diagnoses. One patient from each family was analyzed for whole exome sequencing and Sanger sequencing was done for the rest of the family members. Affected individuals of families BD-06 and MR-01 show complete CMT phenotypes and family ICP-RD11 shows ARSACS type. Family DG-01 shows complete phenotypes for both CMT and ARSACS types. The affected individuals have walking difficulties, ataxia, distal limb weakness, axonal sensorimotor neuropathies, delayed motor development, pes cavus, and speech articulations with minor variations. The WES analysis in an indexed patient of family DG-01 identified two novel variants: c.83G>T (p.Gly28Val) in MPV17 and c.4934G>C (p.Arg1645Pro) in SACS. In family ICP-RD11, a recurrent mutation that causes ARSACS, c.262C>T (p.Arg88Ter) in SACS, was identified. Another novel variant, c.231C>A (p.Arg77Ter) in PRX, which causes CMT4F, was identified in family BD-06. In family MR-01, a hemizygous missense variant c.61G>C (p.Gly21Arg) in GJB1 was identified in the indexed patient. To the best of our knowledge, there are very few reports on MPV17, SACS, PRX, and GJB1 causing CMT and ARSACS phenotypes in the Pakistani population. Our study cohort suggests that whole exome sequencing can be a useful tool in diagnosing complex multigenic and phenotypically overlapping genetic disorders such as Charcot-Marie-Tooth disease (CMT) and spastic ataxia of Charlevoix-Saguenay type.
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Affiliation(s)
- Qaiser Zaman
- Department of Zoology, Government Postgraduate College Dargai, Malakand 23060, Pakistan
- Higher Education Department, Government of Khyber Pakhtunkhwa, Peshawar 24550, Pakistan
- Department of Zoology, Abdul Wali Khan University, Mardan 23200, Pakistan
| | - Muhammad Abbas Khan
- Department of Zoology, Government Postgraduate College Dargai, Malakand 23060, Pakistan
- Higher Education Department, Government of Khyber Pakhtunkhwa, Peshawar 24550, Pakistan
| | - Kalsoom Sahar
- Department of Zoology, Government Postgraduate College Dargai, Malakand 23060, Pakistan
- Higher Education Department, Government of Khyber Pakhtunkhwa, Peshawar 24550, Pakistan
| | - Gauhar Rehman
- Department of Zoology, Abdul Wali Khan University, Mardan 23200, Pakistan
| | - Hamza Khan
- Department of Zoology, Government Postgraduate College Dargai, Malakand 23060, Pakistan
- Higher Education Department, Government of Khyber Pakhtunkhwa, Peshawar 24550, Pakistan
| | - Mehwish Rehman
- Department of Zoology, Government Postgraduate College Dargai, Malakand 23060, Pakistan
- Higher Education Department, Government of Khyber Pakhtunkhwa, Peshawar 24550, Pakistan
| | - Najumuddin
- National Center for Bioinformatics, Quid-I-Azam University, Islamabad 45320, Pakistan
| | - Ilyas Ahmad
- Institute for Cardiogenetics, University of Lübeck, DZHK (German Research Centre for Cardiovascular Research), Partner Site Hamburg/Lübeck/Kiel, and University Heart Centre Lübeck, 23562 Lübeck, Germany
| | - Muhmmad Tariq
- Rare Diseases Genetics and Genomics, Centre for Omic Sciences, Islamia College, Peshawar 25120, Pakistan
| | - Osama Yousef Muthaffar
- Department of Pediatrics, Faculty of Medicine, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Angham Abdulrhman Abdulkareem
- Department of Biochemistry, Faculty of Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia
- Center of Excellence in Genomic Medicine Research, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Fehmida Bibi
- Special Infectious Agents Unit, King Fahd Medical Research Centre, King Abdulaziz University, Jeddah 21589, Saudi Arabia
- Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Muhammad Imran Naseer
- Center of Excellence in Genomic Medicine Research, King Abdulaziz University, Jeddah 21589, Saudi Arabia
- Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Muhammad Shah Faisal
- Rare Diseases Genetics and Genomics, Centre for Omic Sciences, Islamia College, Peshawar 25120, Pakistan
| | - Naveed Wasif
- Institute of Human Genetics, Ulm University Medical Center, Ulm University, 89081 Ulm, Germany
- Institute of Human Genetics, University Hospital Schleswig-Holstein, Campus Lübeck, 23538 Lübeck, Germany
| | - Musharraf Jelani
- Rare Diseases Genetics and Genomics, Centre for Omic Sciences, Islamia College, Peshawar 25120, Pakistan
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Moss KR, Bopp TS, Johnson AE, Höke A. New evidence for secondary axonal degeneration in demyelinating neuropathies. Neurosci Lett 2021; 744:135595. [PMID: 33359733 PMCID: PMC7852893 DOI: 10.1016/j.neulet.2020.135595] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Revised: 10/31/2020] [Accepted: 12/19/2020] [Indexed: 12/28/2022]
Abstract
Development of peripheral nervous system (PNS) myelin involves a coordinated series of events between growing axons and the Schwann cell (SC) progenitors that will eventually ensheath them. Myelin sheaths have evolved out of necessity to maintain rapid impulse propagation while accounting for body space constraints. However, myelinating SCs perform additional critical functions that are required to preserve axonal integrity including mitigating energy consumption by establishing the nodal architecture, regulating axon caliber by organizing axonal cytoskeleton networks, providing trophic and potentially metabolic support, possibly supplying genetic translation materials and protecting axons from toxic insults. The intermediate steps between the loss of these functions and the initiation of axon degeneration are unknown but the importance of these processes provides insightful clues. Prevalent demyelinating diseases of the PNS include the inherited neuropathies Charcot-Marie-Tooth Disease, Type 1 (CMT1) and Hereditary Neuropathy with Liability to Pressure Palsies (HNPP) and the inflammatory diseases Acute Inflammatory Demyelinating Polyneuropathy (AIDP) and Chronic Inflammatory Demyelinating Polyneuropathy (CIDP). Secondary axon degeneration is a common feature of demyelinating neuropathies and this process is often correlated with clinical deficits and long-lasting disability in patients. There is abundant electrophysiological and histological evidence for secondary axon degeneration in patients and rodent models of PNS demyelinating diseases. Fully understanding the involvement of secondary axon degeneration in these diseases is essential for expanding our knowledge of disease pathogenesis and prognosis, which will be essential for developing novel therapeutic strategies.
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Affiliation(s)
- Kathryn R Moss
- Department of Neurology, Neuromuscular Division, Johns Hopkins School of Medicine, Baltimore, MD, United States
| | - Taylor S Bopp
- Department of Neurology, Neuromuscular Division, Johns Hopkins School of Medicine, Baltimore, MD, United States
| | - Anna E Johnson
- Department of Neurology, Neuromuscular Division, Johns Hopkins School of Medicine, Baltimore, MD, United States
| | - Ahmet Höke
- Department of Neurology, Neuromuscular Division, Johns Hopkins School of Medicine, Baltimore, MD, United States.
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6
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Liu Y, Xue J, Li Z, Linpeng S, Tan H, Teng Y, Liang D, Wu L. A novel GJB1 mutation associated with X-linked Charcot-Marie-Tooth disease in a large Chinese family pedigree. Mol Genet Genomic Med 2020; 8:e1127. [PMID: 31943912 PMCID: PMC7057093 DOI: 10.1002/mgg3.1127] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Revised: 12/19/2019] [Accepted: 01/02/2020] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Charcot-Marie-Tooth (CMT) disease is a group of hereditary neuropathies with high phenotypic and genetic heterogeneity. In this study, we report a large family with X-linked CMT (CMTX) caused by a novel GJB1 mutation. METHODS A family with the clinical diagnosis of CMTX was investigated. For mutation analysis, the coding region of GJB1 was sequenced using DNA from 15 family members. The identified GJB1 mutation was investigated by DHPLC in 120 normal controls. Mutation reanalysis was performed based on whole-exome sequencing (WES). Cell transfection studies were performed to characterize the function of the novel mutation. RESULTS A missense mutation (c.605T>A) in GJB1 was detected in five patients and eight female carriers but not in two unaffected members of the family. The mutation was not found in 120 healthy controls and has not been previously reported. WES excluded other pathogenic mutations in the family. The pathogenicity of the mutation was confirmed by disrupting the membrane localization of the encoded proteins. CONCLUSION Our findings demonstrate that a novel mutation (c.605T>A) in GJB1 is associated with CMTX and adds to the repertoire of GJB1 mutations related to CMTX.
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Affiliation(s)
- Yingdi Liu
- Center for Medical Genetics & Hunan Key Laboratory of Medical GeneticsSchool of Life SciencesCentral South UniversityChangshaChina
| | - Jinjie Xue
- Center for Medical Genetics & Hunan Key Laboratory of Medical GeneticsSchool of Life SciencesCentral South UniversityChangshaChina
- Children's Hospital of ShanxiWomen Health Center of ShanxiTaiyuanChina
| | - Zhuo Li
- Center for Medical Genetics & Hunan Key Laboratory of Medical GeneticsSchool of Life SciencesCentral South UniversityChangshaChina
| | - Siyuan Linpeng
- Center for Medical Genetics & Hunan Key Laboratory of Medical GeneticsSchool of Life SciencesCentral South UniversityChangshaChina
| | - Hu Tan
- Center for Medical Genetics & Hunan Key Laboratory of Medical GeneticsSchool of Life SciencesCentral South UniversityChangshaChina
| | | | - Desheng Liang
- Center for Medical Genetics & Hunan Key Laboratory of Medical GeneticsSchool of Life SciencesCentral South UniversityChangshaChina
| | - Lingqian Wu
- Center for Medical Genetics & Hunan Key Laboratory of Medical GeneticsSchool of Life SciencesCentral South UniversityChangshaChina
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Sahenk Z, Ozes B. Gene therapy to promote regeneration in Charcot-Marie-Tooth disease. Brain Res 2019; 1727:146533. [PMID: 31669284 DOI: 10.1016/j.brainres.2019.146533] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Revised: 10/20/2019] [Accepted: 10/22/2019] [Indexed: 12/12/2022]
Abstract
The molecular pathogenesis underlying Charcot-Marie-Tooth (CMT) neuropathy subtypes is becoming increasingly variable and identification of common approaches for treatment, independently of the disease causing gene defect, is therefore much desirable. Gene therapy approach from the clinical translational view point is particularly challenging for the most common "demyelinating" CMT1 subtypes, caused by primary Schwann cell genetic defects. Studies have shown that impaired regenerative capacity of distal axons is major contributing factor to distal axonal loss in primary Schwann cell genetic defects and neurotrophin 3 (NT-3) improves impaired regeneration in CMT1 mouse models. This review surveys the evidence supporting the rationale for AAV1.NT-3 surrogate gene therapy to improve nerve regeneration in CMT1A. The translational process, from proof of principal studies to the design of the phase I/IIa trial evaluating scAAV1.tMCK.NTF3 gene therapy for treatment of CMT1A is summarized.
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Affiliation(s)
- Zarife Sahenk
- Center for Gene Therapy, Abigail Wexner Research Institute, Nationwide Children's Hospital, Columbus, OH, United States; Department of Pediatrics and Neurology, Nationwide Children's Hospital and The Ohio State University, United States; Department of Pathology and Laboratory Medicine, Nationwide Children's Hospital, Columbus, OH, United States; Department of Neurology, The Ohio State University, United States.
| | - Burcak Ozes
- Center for Gene Therapy, Abigail Wexner Research Institute, Nationwide Children's Hospital, Columbus, OH, United States
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Nam SH, Choi BO. Clinical and genetic aspects of Charcot-Marie-Tooth disease subtypes. PRECISION AND FUTURE MEDICINE 2019. [DOI: 10.23838/pfm.2018.00163] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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Diseases of connexins expressed in myelinating glia. Neurosci Lett 2019; 695:91-99. [DOI: 10.1016/j.neulet.2017.05.037] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 05/15/2017] [Accepted: 05/19/2017] [Indexed: 11/23/2022]
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McCorquodale D, Smith AG. Clinical electrophysiology of axonal polyneuropathies. HANDBOOK OF CLINICAL NEUROLOGY 2019; 161:217-240. [PMID: 31307603 DOI: 10.1016/b978-0-444-64142-7.00051-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Axonal neuropathies encompass a wide range of acquired and inherited disorders with electrophysiologic characteristics that arise from the unique neurophysiology of the axon. Accurate interpretation of nerve conduction studies and electromyography requires an in-depth understanding of the pathophysiology of the axon. Here we review the unique neurophysiologic properties of the axon and how they relate to clinical electrodiagnostic features. We review the length-dependent Wallerian or "dying-back" processes as well as the emerging body of literature from acquired axonal neuropathies that highlights the importance of axonal disease at the nodes of Ranvier. Neurophysiologic features of individual inherited and acquired axonal diseases, including primary nerve disease as well as systemic immune mediated, metabolic, and toxic diseases involving the peripheral nerve, are reviewed. This comprehensive review of electrodiagnostic findings coupled with the current understanding of pathophysiology will aid the clinician in the evaluation of axonal polyneuropathies.
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Affiliation(s)
- Donald McCorquodale
- Department of Neurology, Virginia Commonwealth University, Richmond, VA, United States
| | - A Gordon Smith
- Department of Neurology, Virginia Commonwealth University, Richmond, VA, United States.
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Kanhangad M, Cornett K, Brewer MH, Nicholson GA, Ryan MM, Smith RL, Subramanian GM, Young HK, Züchner S, Kennerson ML, Burns J, Menezes MP. Unique clinical and neurophysiologic profile of a cohort of children with CMTX3. Neurology 2018; 90:e1706-e1710. [PMID: 29626178 PMCID: PMC10681066 DOI: 10.1212/wnl.0000000000005479] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 02/21/2018] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To describe in detail the clinical profile of Charcot-Marie-Tooth disease subtype 3 (CMTX3) to aid appropriate genetic testing and rehabilitative therapy. METHODS We reviewed the clinical and neurophysiologic profile and CMT Pediatric Scale (CMTPedS) assessments of 11 children with CMTX3. RESULTS Compared with the more common forms of CMT, CMT1A and CMTX, CMTX3 was characterized by early onset with early and progressive hand weakness. Most affected children were symptomatic within the first 2 years of life. The most common presentation was foot deformity in the first year of life. CMTPedS analysis in these children revealed that CMTX3 progressed more rapidly (4.3 ± 4.1 points over 2 years, n = 7) than CMT1A and CMTX1. Grip strength in affected boys was 2 SDs below age- and sex-matched normative reference values (z score -2.05 ± 1.32) in the second decade of life. The most severely affected individual was wheelchair bound at 14 years of age, and 2 individuals had no movement in the small muscles of the hand in the second decade of life. Nerve conduction studies showed a demyelinating sensorimotor neuropathy with motor conduction velocity ≤23 m/s. CONCLUSIONS CMTX3 had an earlier onset, severe hand weakness, and more rapidly progressive disability compared to the more common forms of CMT. Understanding the unique phenotype of CMTX3 is essential for directing genetic testing because the CMTX3 insertion will not be seen on a routine microarray or neuromuscular gene panel. Early diagnosis will enable rehabilitation to be started early in this rapidly progressive neuropathy.
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Affiliation(s)
- Manoj Kanhangad
- From the T.Y. Nelson Department of Neurology and Neurosurgery (M.K., M.P.M.) and Institute for Neuroscience and Muscle Research (K.C., J.B., M.P.M.), The Children's Hospital at Westmead; University of Sydney (K.C., M.H.B., G.A.N., H.K.Y., M.L.K., J.B., M.P.M.); Northcott Neuroscience Laboratory (M.H.B., G.A.N., M.L.K.), ANZAC Research Institute, Concord; Molecular Medicine Laboratory (G.A.N., M.L.K.), Concord Repatriation General Hospital, New South Wales; Department of Neurology (M.M.R.), Royal Children's Hospital; Murdoch Children's Research Institute (M.M.R.); Department of Paediatrics (M.M.R.), University of Melbourne, Parkville, Victoria; Department of Neurology (R.L.S., G.M.S.), John Hunter Children's Hospital, and University Faculty of Health, Newcastle; Department of Paediatrics (H.K.Y.), Royal North Shore Hospital, St. Leonards, New South Wales, Australia; Department of Human Genetics (S.Z.), Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, FL; and Paediatric Gait Analysis Service of New South Wales (J.B.), Sydney Children's Hospitals Network (Randwick and Westmead), Australia
| | - Kayla Cornett
- From the T.Y. Nelson Department of Neurology and Neurosurgery (M.K., M.P.M.) and Institute for Neuroscience and Muscle Research (K.C., J.B., M.P.M.), The Children's Hospital at Westmead; University of Sydney (K.C., M.H.B., G.A.N., H.K.Y., M.L.K., J.B., M.P.M.); Northcott Neuroscience Laboratory (M.H.B., G.A.N., M.L.K.), ANZAC Research Institute, Concord; Molecular Medicine Laboratory (G.A.N., M.L.K.), Concord Repatriation General Hospital, New South Wales; Department of Neurology (M.M.R.), Royal Children's Hospital; Murdoch Children's Research Institute (M.M.R.); Department of Paediatrics (M.M.R.), University of Melbourne, Parkville, Victoria; Department of Neurology (R.L.S., G.M.S.), John Hunter Children's Hospital, and University Faculty of Health, Newcastle; Department of Paediatrics (H.K.Y.), Royal North Shore Hospital, St. Leonards, New South Wales, Australia; Department of Human Genetics (S.Z.), Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, FL; and Paediatric Gait Analysis Service of New South Wales (J.B.), Sydney Children's Hospitals Network (Randwick and Westmead), Australia
| | - Megan H Brewer
- From the T.Y. Nelson Department of Neurology and Neurosurgery (M.K., M.P.M.) and Institute for Neuroscience and Muscle Research (K.C., J.B., M.P.M.), The Children's Hospital at Westmead; University of Sydney (K.C., M.H.B., G.A.N., H.K.Y., M.L.K., J.B., M.P.M.); Northcott Neuroscience Laboratory (M.H.B., G.A.N., M.L.K.), ANZAC Research Institute, Concord; Molecular Medicine Laboratory (G.A.N., M.L.K.), Concord Repatriation General Hospital, New South Wales; Department of Neurology (M.M.R.), Royal Children's Hospital; Murdoch Children's Research Institute (M.M.R.); Department of Paediatrics (M.M.R.), University of Melbourne, Parkville, Victoria; Department of Neurology (R.L.S., G.M.S.), John Hunter Children's Hospital, and University Faculty of Health, Newcastle; Department of Paediatrics (H.K.Y.), Royal North Shore Hospital, St. Leonards, New South Wales, Australia; Department of Human Genetics (S.Z.), Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, FL; and Paediatric Gait Analysis Service of New South Wales (J.B.), Sydney Children's Hospitals Network (Randwick and Westmead), Australia
| | - Garth A Nicholson
- From the T.Y. Nelson Department of Neurology and Neurosurgery (M.K., M.P.M.) and Institute for Neuroscience and Muscle Research (K.C., J.B., M.P.M.), The Children's Hospital at Westmead; University of Sydney (K.C., M.H.B., G.A.N., H.K.Y., M.L.K., J.B., M.P.M.); Northcott Neuroscience Laboratory (M.H.B., G.A.N., M.L.K.), ANZAC Research Institute, Concord; Molecular Medicine Laboratory (G.A.N., M.L.K.), Concord Repatriation General Hospital, New South Wales; Department of Neurology (M.M.R.), Royal Children's Hospital; Murdoch Children's Research Institute (M.M.R.); Department of Paediatrics (M.M.R.), University of Melbourne, Parkville, Victoria; Department of Neurology (R.L.S., G.M.S.), John Hunter Children's Hospital, and University Faculty of Health, Newcastle; Department of Paediatrics (H.K.Y.), Royal North Shore Hospital, St. Leonards, New South Wales, Australia; Department of Human Genetics (S.Z.), Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, FL; and Paediatric Gait Analysis Service of New South Wales (J.B.), Sydney Children's Hospitals Network (Randwick and Westmead), Australia
| | - Monique M Ryan
- From the T.Y. Nelson Department of Neurology and Neurosurgery (M.K., M.P.M.) and Institute for Neuroscience and Muscle Research (K.C., J.B., M.P.M.), The Children's Hospital at Westmead; University of Sydney (K.C., M.H.B., G.A.N., H.K.Y., M.L.K., J.B., M.P.M.); Northcott Neuroscience Laboratory (M.H.B., G.A.N., M.L.K.), ANZAC Research Institute, Concord; Molecular Medicine Laboratory (G.A.N., M.L.K.), Concord Repatriation General Hospital, New South Wales; Department of Neurology (M.M.R.), Royal Children's Hospital; Murdoch Children's Research Institute (M.M.R.); Department of Paediatrics (M.M.R.), University of Melbourne, Parkville, Victoria; Department of Neurology (R.L.S., G.M.S.), John Hunter Children's Hospital, and University Faculty of Health, Newcastle; Department of Paediatrics (H.K.Y.), Royal North Shore Hospital, St. Leonards, New South Wales, Australia; Department of Human Genetics (S.Z.), Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, FL; and Paediatric Gait Analysis Service of New South Wales (J.B.), Sydney Children's Hospitals Network (Randwick and Westmead), Australia
| | - Robert L Smith
- From the T.Y. Nelson Department of Neurology and Neurosurgery (M.K., M.P.M.) and Institute for Neuroscience and Muscle Research (K.C., J.B., M.P.M.), The Children's Hospital at Westmead; University of Sydney (K.C., M.H.B., G.A.N., H.K.Y., M.L.K., J.B., M.P.M.); Northcott Neuroscience Laboratory (M.H.B., G.A.N., M.L.K.), ANZAC Research Institute, Concord; Molecular Medicine Laboratory (G.A.N., M.L.K.), Concord Repatriation General Hospital, New South Wales; Department of Neurology (M.M.R.), Royal Children's Hospital; Murdoch Children's Research Institute (M.M.R.); Department of Paediatrics (M.M.R.), University of Melbourne, Parkville, Victoria; Department of Neurology (R.L.S., G.M.S.), John Hunter Children's Hospital, and University Faculty of Health, Newcastle; Department of Paediatrics (H.K.Y.), Royal North Shore Hospital, St. Leonards, New South Wales, Australia; Department of Human Genetics (S.Z.), Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, FL; and Paediatric Gait Analysis Service of New South Wales (J.B.), Sydney Children's Hospitals Network (Randwick and Westmead), Australia
| | - Gopinath M Subramanian
- From the T.Y. Nelson Department of Neurology and Neurosurgery (M.K., M.P.M.) and Institute for Neuroscience and Muscle Research (K.C., J.B., M.P.M.), The Children's Hospital at Westmead; University of Sydney (K.C., M.H.B., G.A.N., H.K.Y., M.L.K., J.B., M.P.M.); Northcott Neuroscience Laboratory (M.H.B., G.A.N., M.L.K.), ANZAC Research Institute, Concord; Molecular Medicine Laboratory (G.A.N., M.L.K.), Concord Repatriation General Hospital, New South Wales; Department of Neurology (M.M.R.), Royal Children's Hospital; Murdoch Children's Research Institute (M.M.R.); Department of Paediatrics (M.M.R.), University of Melbourne, Parkville, Victoria; Department of Neurology (R.L.S., G.M.S.), John Hunter Children's Hospital, and University Faculty of Health, Newcastle; Department of Paediatrics (H.K.Y.), Royal North Shore Hospital, St. Leonards, New South Wales, Australia; Department of Human Genetics (S.Z.), Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, FL; and Paediatric Gait Analysis Service of New South Wales (J.B.), Sydney Children's Hospitals Network (Randwick and Westmead), Australia
| | - Helen K Young
- From the T.Y. Nelson Department of Neurology and Neurosurgery (M.K., M.P.M.) and Institute for Neuroscience and Muscle Research (K.C., J.B., M.P.M.), The Children's Hospital at Westmead; University of Sydney (K.C., M.H.B., G.A.N., H.K.Y., M.L.K., J.B., M.P.M.); Northcott Neuroscience Laboratory (M.H.B., G.A.N., M.L.K.), ANZAC Research Institute, Concord; Molecular Medicine Laboratory (G.A.N., M.L.K.), Concord Repatriation General Hospital, New South Wales; Department of Neurology (M.M.R.), Royal Children's Hospital; Murdoch Children's Research Institute (M.M.R.); Department of Paediatrics (M.M.R.), University of Melbourne, Parkville, Victoria; Department of Neurology (R.L.S., G.M.S.), John Hunter Children's Hospital, and University Faculty of Health, Newcastle; Department of Paediatrics (H.K.Y.), Royal North Shore Hospital, St. Leonards, New South Wales, Australia; Department of Human Genetics (S.Z.), Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, FL; and Paediatric Gait Analysis Service of New South Wales (J.B.), Sydney Children's Hospitals Network (Randwick and Westmead), Australia
| | - Stephan Züchner
- From the T.Y. Nelson Department of Neurology and Neurosurgery (M.K., M.P.M.) and Institute for Neuroscience and Muscle Research (K.C., J.B., M.P.M.), The Children's Hospital at Westmead; University of Sydney (K.C., M.H.B., G.A.N., H.K.Y., M.L.K., J.B., M.P.M.); Northcott Neuroscience Laboratory (M.H.B., G.A.N., M.L.K.), ANZAC Research Institute, Concord; Molecular Medicine Laboratory (G.A.N., M.L.K.), Concord Repatriation General Hospital, New South Wales; Department of Neurology (M.M.R.), Royal Children's Hospital; Murdoch Children's Research Institute (M.M.R.); Department of Paediatrics (M.M.R.), University of Melbourne, Parkville, Victoria; Department of Neurology (R.L.S., G.M.S.), John Hunter Children's Hospital, and University Faculty of Health, Newcastle; Department of Paediatrics (H.K.Y.), Royal North Shore Hospital, St. Leonards, New South Wales, Australia; Department of Human Genetics (S.Z.), Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, FL; and Paediatric Gait Analysis Service of New South Wales (J.B.), Sydney Children's Hospitals Network (Randwick and Westmead), Australia
| | - Marina L Kennerson
- From the T.Y. Nelson Department of Neurology and Neurosurgery (M.K., M.P.M.) and Institute for Neuroscience and Muscle Research (K.C., J.B., M.P.M.), The Children's Hospital at Westmead; University of Sydney (K.C., M.H.B., G.A.N., H.K.Y., M.L.K., J.B., M.P.M.); Northcott Neuroscience Laboratory (M.H.B., G.A.N., M.L.K.), ANZAC Research Institute, Concord; Molecular Medicine Laboratory (G.A.N., M.L.K.), Concord Repatriation General Hospital, New South Wales; Department of Neurology (M.M.R.), Royal Children's Hospital; Murdoch Children's Research Institute (M.M.R.); Department of Paediatrics (M.M.R.), University of Melbourne, Parkville, Victoria; Department of Neurology (R.L.S., G.M.S.), John Hunter Children's Hospital, and University Faculty of Health, Newcastle; Department of Paediatrics (H.K.Y.), Royal North Shore Hospital, St. Leonards, New South Wales, Australia; Department of Human Genetics (S.Z.), Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, FL; and Paediatric Gait Analysis Service of New South Wales (J.B.), Sydney Children's Hospitals Network (Randwick and Westmead), Australia
| | - Joshua Burns
- From the T.Y. Nelson Department of Neurology and Neurosurgery (M.K., M.P.M.) and Institute for Neuroscience and Muscle Research (K.C., J.B., M.P.M.), The Children's Hospital at Westmead; University of Sydney (K.C., M.H.B., G.A.N., H.K.Y., M.L.K., J.B., M.P.M.); Northcott Neuroscience Laboratory (M.H.B., G.A.N., M.L.K.), ANZAC Research Institute, Concord; Molecular Medicine Laboratory (G.A.N., M.L.K.), Concord Repatriation General Hospital, New South Wales; Department of Neurology (M.M.R.), Royal Children's Hospital; Murdoch Children's Research Institute (M.M.R.); Department of Paediatrics (M.M.R.), University of Melbourne, Parkville, Victoria; Department of Neurology (R.L.S., G.M.S.), John Hunter Children's Hospital, and University Faculty of Health, Newcastle; Department of Paediatrics (H.K.Y.), Royal North Shore Hospital, St. Leonards, New South Wales, Australia; Department of Human Genetics (S.Z.), Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, FL; and Paediatric Gait Analysis Service of New South Wales (J.B.), Sydney Children's Hospitals Network (Randwick and Westmead), Australia
| | - Manoj P Menezes
- From the T.Y. Nelson Department of Neurology and Neurosurgery (M.K., M.P.M.) and Institute for Neuroscience and Muscle Research (K.C., J.B., M.P.M.), The Children's Hospital at Westmead; University of Sydney (K.C., M.H.B., G.A.N., H.K.Y., M.L.K., J.B., M.P.M.); Northcott Neuroscience Laboratory (M.H.B., G.A.N., M.L.K.), ANZAC Research Institute, Concord; Molecular Medicine Laboratory (G.A.N., M.L.K.), Concord Repatriation General Hospital, New South Wales; Department of Neurology (M.M.R.), Royal Children's Hospital; Murdoch Children's Research Institute (M.M.R.); Department of Paediatrics (M.M.R.), University of Melbourne, Parkville, Victoria; Department of Neurology (R.L.S., G.M.S.), John Hunter Children's Hospital, and University Faculty of Health, Newcastle; Department of Paediatrics (H.K.Y.), Royal North Shore Hospital, St. Leonards, New South Wales, Australia; Department of Human Genetics (S.Z.), Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, FL; and Paediatric Gait Analysis Service of New South Wales (J.B.), Sydney Children's Hospitals Network (Randwick and Westmead), Australia.
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Hong YB, Park JM, Yu JS, Yoo DH, Nam DE, Park HJ, Lee JS, Hwang SH, Chung KW, Choi BO. Clinical characterization and genetic analysis of Korean patients with X-linked Charcot-Marie-Tooth disease type 1. J Peripher Nerv Syst 2017; 22:172-181. [PMID: 28448691 DOI: 10.1111/jns.12217] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 04/17/2017] [Accepted: 04/17/2017] [Indexed: 11/30/2022]
Abstract
Mutations in the gap junction protein beta 1 gene (GJB1) cause X-linked Charcot-Marie-Tooth disease type 1 (CMTX1). CMTX1 is representative of the intermediate type of CMT, having both demyelinating and axonal neuropathic features. We analyzed the clinical and genetic characterization of 128 patients with CMTX1 from 63 unrelated families. Genetic analysis revealed a total of 43 mutations including 6 novel mutations. Ten mutations were found from two or more unrelated families. p.V95M was most frequently observed. The frequency of CMTX1 was 9.6% of total Korean CMT family and was 14.8% when calculated within genetically identified cases. Among 67 male and 61 female patients, 22 females were asymptomatic. A high-arched foot, ataxia, and tremor were observed in 87%, 41%, and 35% of the patients, respectively. In the male patients, functional disability scale, CMT neuropathy score, and compound muscle action potential of the median/ulnar nerves were more severely affected than in the female patients. This study provides a comprehensive summary of the clinical features and spectrum of GJB1 gene mutations in Korean CMTX1 patients.
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Affiliation(s)
- Young B Hong
- Stem Cell & Regenerative Medicine Institute, Samsung Medical Center, Seoul, Korea
| | - Jin-Mo Park
- Department of Neurology, College of Medicine, Dongguk University, Gyeongju, Korea
| | - Jin S Yu
- Department of Biological Sciences, Kongju National University, Gongju, Korea
| | - Da H Yoo
- Department of Biological Sciences, Kongju National University, Gongju, Korea
| | - Da E Nam
- Department of Biological Sciences, Kongju National University, Gongju, Korea
| | - Hyung J Park
- Department of Neurology, Mokdong Hospital, Ewha Womans University School of Medicine, Seoul, Korea
| | - Ji-Su Lee
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Sun H Hwang
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Ki W Chung
- Department of Biological Sciences, Kongju National University, Gongju, Korea
| | - Byung-Ok Choi
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
- Neuroscience Center, Samsung Medical Center, Seoul, Korea
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Panosyan FB, Laura M, Rossor AM, Pisciotta C, Piscosquito G, Burns J, Li J, Yum SW, Lewis RA, Day J, Horvath R, Herrmann DN, Shy ME, Pareyson D, Reilly MM, Scherer SS. Cross-sectional analysis of a large cohort with X-linked Charcot-Marie-Tooth disease (CMTX1). Neurology 2017; 89:927-935. [PMID: 28768847 PMCID: PMC5577965 DOI: 10.1212/wnl.0000000000004296] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Accepted: 06/05/2017] [Indexed: 12/13/2022] Open
Abstract
OBJECTIVE To extend the phenotypic description of Charcot-Marie-Tooth disease (CMTX1) and to draw new genotype-phenotype relationships. METHODS Mutations in GJB1 cause the main X-linked form of CMTX (CMTX1). We report cross-sectional data from 160 patients (from 120 different families, with 89 different mutations) seen at the Inherited Neuropathies Consortium centers. RESULTS We evaluated 87 males who had a mean age of 41 years (range 10-78 years) and 73 females who had a mean age of 46 years (range 15-84 years). Sensory-motor polyneuropathy affects both sexes, more severely in males than in females, and there was a strong correlation between age and disease burden in males but not in females. Compared with females, males had more severe reduction in motor and sensory neurophysiology parameters. In contrast to females, the radial nerve sensory response in older males tended to be more severely affected compared with younger males. Median and ulnar nerve motor amplitudes were also more severely affected in older males, whereas ulnar nerve motor potentials tended to be more affected in older females. Conversely, there were no statistical differences between the sexes in other features of the disease, such as problems with balance and hand dexterity. CONCLUSIONS In the absence of a phenotypic correlation with specific GJB1 mutations, sex-specific distinctions and clinically relevant attributes need to be incorporated into the measurements for clinical trials in people with CMTX1. CLINICALTRIALSGOV IDENTIFIER NCT01193075.
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Affiliation(s)
- Francis B Panosyan
- From the Department of Neurology (F.B.P., D.N.H.), University of Rochester Medical Center, NY; MRC Centre for Neuromuscular Diseases (M.L., A.M.R., M.M.R.), UCL Institute of Neurology, UK; Department of Neurology (C.P., D.P.), Carlo Besta Neurological Institute, Milan, Italy; Department of Neurosciences (G.P.), Institute of Telese Terme (BN), Italy; Children's Hospital at Westmead (J.B.), University of Sydney, Australia; Department of Neurology (J.L.), Vanderbilt University, Nashville, TN; Neuromuscular Program (S.W.Y.), Children's Hospital of Philadelphia, PA; Department of Neurology (R.A.L.), Cedars-Sinai Medical Center, Los Angeles, CA; Department of Neurology (J.D.), Stanford University, CA; Institute of Genetic Medicine (R.H.), Newcastle University, UK; Department of Neurology (M.E.S.), University of Iowa Hospitals and Clinics; and Department of Neurology (S.S.S.), University of Pennsylvania, Philadelphia.
| | - Matilde Laura
- From the Department of Neurology (F.B.P., D.N.H.), University of Rochester Medical Center, NY; MRC Centre for Neuromuscular Diseases (M.L., A.M.R., M.M.R.), UCL Institute of Neurology, UK; Department of Neurology (C.P., D.P.), Carlo Besta Neurological Institute, Milan, Italy; Department of Neurosciences (G.P.), Institute of Telese Terme (BN), Italy; Children's Hospital at Westmead (J.B.), University of Sydney, Australia; Department of Neurology (J.L.), Vanderbilt University, Nashville, TN; Neuromuscular Program (S.W.Y.), Children's Hospital of Philadelphia, PA; Department of Neurology (R.A.L.), Cedars-Sinai Medical Center, Los Angeles, CA; Department of Neurology (J.D.), Stanford University, CA; Institute of Genetic Medicine (R.H.), Newcastle University, UK; Department of Neurology (M.E.S.), University of Iowa Hospitals and Clinics; and Department of Neurology (S.S.S.), University of Pennsylvania, Philadelphia
| | - Alexander M Rossor
- From the Department of Neurology (F.B.P., D.N.H.), University of Rochester Medical Center, NY; MRC Centre for Neuromuscular Diseases (M.L., A.M.R., M.M.R.), UCL Institute of Neurology, UK; Department of Neurology (C.P., D.P.), Carlo Besta Neurological Institute, Milan, Italy; Department of Neurosciences (G.P.), Institute of Telese Terme (BN), Italy; Children's Hospital at Westmead (J.B.), University of Sydney, Australia; Department of Neurology (J.L.), Vanderbilt University, Nashville, TN; Neuromuscular Program (S.W.Y.), Children's Hospital of Philadelphia, PA; Department of Neurology (R.A.L.), Cedars-Sinai Medical Center, Los Angeles, CA; Department of Neurology (J.D.), Stanford University, CA; Institute of Genetic Medicine (R.H.), Newcastle University, UK; Department of Neurology (M.E.S.), University of Iowa Hospitals and Clinics; and Department of Neurology (S.S.S.), University of Pennsylvania, Philadelphia
| | - Chiara Pisciotta
- From the Department of Neurology (F.B.P., D.N.H.), University of Rochester Medical Center, NY; MRC Centre for Neuromuscular Diseases (M.L., A.M.R., M.M.R.), UCL Institute of Neurology, UK; Department of Neurology (C.P., D.P.), Carlo Besta Neurological Institute, Milan, Italy; Department of Neurosciences (G.P.), Institute of Telese Terme (BN), Italy; Children's Hospital at Westmead (J.B.), University of Sydney, Australia; Department of Neurology (J.L.), Vanderbilt University, Nashville, TN; Neuromuscular Program (S.W.Y.), Children's Hospital of Philadelphia, PA; Department of Neurology (R.A.L.), Cedars-Sinai Medical Center, Los Angeles, CA; Department of Neurology (J.D.), Stanford University, CA; Institute of Genetic Medicine (R.H.), Newcastle University, UK; Department of Neurology (M.E.S.), University of Iowa Hospitals and Clinics; and Department of Neurology (S.S.S.), University of Pennsylvania, Philadelphia
| | - Giuseppe Piscosquito
- From the Department of Neurology (F.B.P., D.N.H.), University of Rochester Medical Center, NY; MRC Centre for Neuromuscular Diseases (M.L., A.M.R., M.M.R.), UCL Institute of Neurology, UK; Department of Neurology (C.P., D.P.), Carlo Besta Neurological Institute, Milan, Italy; Department of Neurosciences (G.P.), Institute of Telese Terme (BN), Italy; Children's Hospital at Westmead (J.B.), University of Sydney, Australia; Department of Neurology (J.L.), Vanderbilt University, Nashville, TN; Neuromuscular Program (S.W.Y.), Children's Hospital of Philadelphia, PA; Department of Neurology (R.A.L.), Cedars-Sinai Medical Center, Los Angeles, CA; Department of Neurology (J.D.), Stanford University, CA; Institute of Genetic Medicine (R.H.), Newcastle University, UK; Department of Neurology (M.E.S.), University of Iowa Hospitals and Clinics; and Department of Neurology (S.S.S.), University of Pennsylvania, Philadelphia
| | - Joshua Burns
- From the Department of Neurology (F.B.P., D.N.H.), University of Rochester Medical Center, NY; MRC Centre for Neuromuscular Diseases (M.L., A.M.R., M.M.R.), UCL Institute of Neurology, UK; Department of Neurology (C.P., D.P.), Carlo Besta Neurological Institute, Milan, Italy; Department of Neurosciences (G.P.), Institute of Telese Terme (BN), Italy; Children's Hospital at Westmead (J.B.), University of Sydney, Australia; Department of Neurology (J.L.), Vanderbilt University, Nashville, TN; Neuromuscular Program (S.W.Y.), Children's Hospital of Philadelphia, PA; Department of Neurology (R.A.L.), Cedars-Sinai Medical Center, Los Angeles, CA; Department of Neurology (J.D.), Stanford University, CA; Institute of Genetic Medicine (R.H.), Newcastle University, UK; Department of Neurology (M.E.S.), University of Iowa Hospitals and Clinics; and Department of Neurology (S.S.S.), University of Pennsylvania, Philadelphia
| | - Jun Li
- From the Department of Neurology (F.B.P., D.N.H.), University of Rochester Medical Center, NY; MRC Centre for Neuromuscular Diseases (M.L., A.M.R., M.M.R.), UCL Institute of Neurology, UK; Department of Neurology (C.P., D.P.), Carlo Besta Neurological Institute, Milan, Italy; Department of Neurosciences (G.P.), Institute of Telese Terme (BN), Italy; Children's Hospital at Westmead (J.B.), University of Sydney, Australia; Department of Neurology (J.L.), Vanderbilt University, Nashville, TN; Neuromuscular Program (S.W.Y.), Children's Hospital of Philadelphia, PA; Department of Neurology (R.A.L.), Cedars-Sinai Medical Center, Los Angeles, CA; Department of Neurology (J.D.), Stanford University, CA; Institute of Genetic Medicine (R.H.), Newcastle University, UK; Department of Neurology (M.E.S.), University of Iowa Hospitals and Clinics; and Department of Neurology (S.S.S.), University of Pennsylvania, Philadelphia
| | - Sabrina W Yum
- From the Department of Neurology (F.B.P., D.N.H.), University of Rochester Medical Center, NY; MRC Centre for Neuromuscular Diseases (M.L., A.M.R., M.M.R.), UCL Institute of Neurology, UK; Department of Neurology (C.P., D.P.), Carlo Besta Neurological Institute, Milan, Italy; Department of Neurosciences (G.P.), Institute of Telese Terme (BN), Italy; Children's Hospital at Westmead (J.B.), University of Sydney, Australia; Department of Neurology (J.L.), Vanderbilt University, Nashville, TN; Neuromuscular Program (S.W.Y.), Children's Hospital of Philadelphia, PA; Department of Neurology (R.A.L.), Cedars-Sinai Medical Center, Los Angeles, CA; Department of Neurology (J.D.), Stanford University, CA; Institute of Genetic Medicine (R.H.), Newcastle University, UK; Department of Neurology (M.E.S.), University of Iowa Hospitals and Clinics; and Department of Neurology (S.S.S.), University of Pennsylvania, Philadelphia
| | - Richard A Lewis
- From the Department of Neurology (F.B.P., D.N.H.), University of Rochester Medical Center, NY; MRC Centre for Neuromuscular Diseases (M.L., A.M.R., M.M.R.), UCL Institute of Neurology, UK; Department of Neurology (C.P., D.P.), Carlo Besta Neurological Institute, Milan, Italy; Department of Neurosciences (G.P.), Institute of Telese Terme (BN), Italy; Children's Hospital at Westmead (J.B.), University of Sydney, Australia; Department of Neurology (J.L.), Vanderbilt University, Nashville, TN; Neuromuscular Program (S.W.Y.), Children's Hospital of Philadelphia, PA; Department of Neurology (R.A.L.), Cedars-Sinai Medical Center, Los Angeles, CA; Department of Neurology (J.D.), Stanford University, CA; Institute of Genetic Medicine (R.H.), Newcastle University, UK; Department of Neurology (M.E.S.), University of Iowa Hospitals and Clinics; and Department of Neurology (S.S.S.), University of Pennsylvania, Philadelphia
| | - John Day
- From the Department of Neurology (F.B.P., D.N.H.), University of Rochester Medical Center, NY; MRC Centre for Neuromuscular Diseases (M.L., A.M.R., M.M.R.), UCL Institute of Neurology, UK; Department of Neurology (C.P., D.P.), Carlo Besta Neurological Institute, Milan, Italy; Department of Neurosciences (G.P.), Institute of Telese Terme (BN), Italy; Children's Hospital at Westmead (J.B.), University of Sydney, Australia; Department of Neurology (J.L.), Vanderbilt University, Nashville, TN; Neuromuscular Program (S.W.Y.), Children's Hospital of Philadelphia, PA; Department of Neurology (R.A.L.), Cedars-Sinai Medical Center, Los Angeles, CA; Department of Neurology (J.D.), Stanford University, CA; Institute of Genetic Medicine (R.H.), Newcastle University, UK; Department of Neurology (M.E.S.), University of Iowa Hospitals and Clinics; and Department of Neurology (S.S.S.), University of Pennsylvania, Philadelphia
| | - Rita Horvath
- From the Department of Neurology (F.B.P., D.N.H.), University of Rochester Medical Center, NY; MRC Centre for Neuromuscular Diseases (M.L., A.M.R., M.M.R.), UCL Institute of Neurology, UK; Department of Neurology (C.P., D.P.), Carlo Besta Neurological Institute, Milan, Italy; Department of Neurosciences (G.P.), Institute of Telese Terme (BN), Italy; Children's Hospital at Westmead (J.B.), University of Sydney, Australia; Department of Neurology (J.L.), Vanderbilt University, Nashville, TN; Neuromuscular Program (S.W.Y.), Children's Hospital of Philadelphia, PA; Department of Neurology (R.A.L.), Cedars-Sinai Medical Center, Los Angeles, CA; Department of Neurology (J.D.), Stanford University, CA; Institute of Genetic Medicine (R.H.), Newcastle University, UK; Department of Neurology (M.E.S.), University of Iowa Hospitals and Clinics; and Department of Neurology (S.S.S.), University of Pennsylvania, Philadelphia
| | - David N Herrmann
- From the Department of Neurology (F.B.P., D.N.H.), University of Rochester Medical Center, NY; MRC Centre for Neuromuscular Diseases (M.L., A.M.R., M.M.R.), UCL Institute of Neurology, UK; Department of Neurology (C.P., D.P.), Carlo Besta Neurological Institute, Milan, Italy; Department of Neurosciences (G.P.), Institute of Telese Terme (BN), Italy; Children's Hospital at Westmead (J.B.), University of Sydney, Australia; Department of Neurology (J.L.), Vanderbilt University, Nashville, TN; Neuromuscular Program (S.W.Y.), Children's Hospital of Philadelphia, PA; Department of Neurology (R.A.L.), Cedars-Sinai Medical Center, Los Angeles, CA; Department of Neurology (J.D.), Stanford University, CA; Institute of Genetic Medicine (R.H.), Newcastle University, UK; Department of Neurology (M.E.S.), University of Iowa Hospitals and Clinics; and Department of Neurology (S.S.S.), University of Pennsylvania, Philadelphia
| | - Michael E Shy
- From the Department of Neurology (F.B.P., D.N.H.), University of Rochester Medical Center, NY; MRC Centre for Neuromuscular Diseases (M.L., A.M.R., M.M.R.), UCL Institute of Neurology, UK; Department of Neurology (C.P., D.P.), Carlo Besta Neurological Institute, Milan, Italy; Department of Neurosciences (G.P.), Institute of Telese Terme (BN), Italy; Children's Hospital at Westmead (J.B.), University of Sydney, Australia; Department of Neurology (J.L.), Vanderbilt University, Nashville, TN; Neuromuscular Program (S.W.Y.), Children's Hospital of Philadelphia, PA; Department of Neurology (R.A.L.), Cedars-Sinai Medical Center, Los Angeles, CA; Department of Neurology (J.D.), Stanford University, CA; Institute of Genetic Medicine (R.H.), Newcastle University, UK; Department of Neurology (M.E.S.), University of Iowa Hospitals and Clinics; and Department of Neurology (S.S.S.), University of Pennsylvania, Philadelphia
| | - Davide Pareyson
- From the Department of Neurology (F.B.P., D.N.H.), University of Rochester Medical Center, NY; MRC Centre for Neuromuscular Diseases (M.L., A.M.R., M.M.R.), UCL Institute of Neurology, UK; Department of Neurology (C.P., D.P.), Carlo Besta Neurological Institute, Milan, Italy; Department of Neurosciences (G.P.), Institute of Telese Terme (BN), Italy; Children's Hospital at Westmead (J.B.), University of Sydney, Australia; Department of Neurology (J.L.), Vanderbilt University, Nashville, TN; Neuromuscular Program (S.W.Y.), Children's Hospital of Philadelphia, PA; Department of Neurology (R.A.L.), Cedars-Sinai Medical Center, Los Angeles, CA; Department of Neurology (J.D.), Stanford University, CA; Institute of Genetic Medicine (R.H.), Newcastle University, UK; Department of Neurology (M.E.S.), University of Iowa Hospitals and Clinics; and Department of Neurology (S.S.S.), University of Pennsylvania, Philadelphia
| | - Mary M Reilly
- From the Department of Neurology (F.B.P., D.N.H.), University of Rochester Medical Center, NY; MRC Centre for Neuromuscular Diseases (M.L., A.M.R., M.M.R.), UCL Institute of Neurology, UK; Department of Neurology (C.P., D.P.), Carlo Besta Neurological Institute, Milan, Italy; Department of Neurosciences (G.P.), Institute of Telese Terme (BN), Italy; Children's Hospital at Westmead (J.B.), University of Sydney, Australia; Department of Neurology (J.L.), Vanderbilt University, Nashville, TN; Neuromuscular Program (S.W.Y.), Children's Hospital of Philadelphia, PA; Department of Neurology (R.A.L.), Cedars-Sinai Medical Center, Los Angeles, CA; Department of Neurology (J.D.), Stanford University, CA; Institute of Genetic Medicine (R.H.), Newcastle University, UK; Department of Neurology (M.E.S.), University of Iowa Hospitals and Clinics; and Department of Neurology (S.S.S.), University of Pennsylvania, Philadelphia
| | - Steven S Scherer
- From the Department of Neurology (F.B.P., D.N.H.), University of Rochester Medical Center, NY; MRC Centre for Neuromuscular Diseases (M.L., A.M.R., M.M.R.), UCL Institute of Neurology, UK; Department of Neurology (C.P., D.P.), Carlo Besta Neurological Institute, Milan, Italy; Department of Neurosciences (G.P.), Institute of Telese Terme (BN), Italy; Children's Hospital at Westmead (J.B.), University of Sydney, Australia; Department of Neurology (J.L.), Vanderbilt University, Nashville, TN; Neuromuscular Program (S.W.Y.), Children's Hospital of Philadelphia, PA; Department of Neurology (R.A.L.), Cedars-Sinai Medical Center, Los Angeles, CA; Department of Neurology (J.D.), Stanford University, CA; Institute of Genetic Medicine (R.H.), Newcastle University, UK; Department of Neurology (M.E.S.), University of Iowa Hospitals and Clinics; and Department of Neurology (S.S.S.), University of Pennsylvania, Philadelphia
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14
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Intermediate Charcot–Marie–Tooth disease: an electrophysiological reappraisal and systematic review. J Neurol 2017; 264:1655-1677. [DOI: 10.1007/s00415-017-8474-3] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 03/23/2017] [Accepted: 03/24/2017] [Indexed: 01/13/2023]
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15
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Abrams CK, Freidin M. GJB1-associated X-linked Charcot-Marie-Tooth disease, a disorder affecting the central and peripheral nervous systems. Cell Tissue Res 2015; 360:659-73. [PMID: 25370202 DOI: 10.1007/s00441-014-2014-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 09/22/2014] [Indexed: 11/24/2022]
Abstract
Charcot-Marie-Tooth disease (CMT) is a group of inherited diseases characterized by exclusive or predominant involvement of the peripheral nervous system. Mutations in GJB1, the gene encoding Connexin 32 (Cx32), a gap-junction channel forming protein, cause the most common X-linked form of CMT, CMT1X. Cx32 is expressed in Schwann cells and oligodendrocytes, the myelinating glia of the peripheral and central nervous systems, respectively. Thus, patients with CMT1X have both central and peripheral nervous system manifestations. Study of the genetics of CMT1X and the phenotypes of patients with this disorder suggest that the peripheral manifestations of CMT1X are likely to be due to loss of function, while in the CNS gain of function may contribute. Mice with targeted ablation of Gjb1 develop a peripheral neuropathy similar to that seen in patients with CMT1X, supporting loss of function as a mechanism for the peripheral manifestations of this disorder. Possible roles for Cx32 include the establishment of a reflexive gap junction pathway in the peripheral and central nervous system and of a panglial syncitium in the central nervous system.
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Affiliation(s)
- Charles K Abrams
- Departments of Neurology and Physiology & Pharmacology, State University of New York, Brooklyn, NY, 11203, USA,
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16
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Li J. Molecular regulators of nerve conduction - Lessons from inherited neuropathies and rodent genetic models. Exp Neurol 2015; 267:209-18. [PMID: 25792482 DOI: 10.1016/j.expneurol.2015.03.009] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Revised: 03/09/2015] [Accepted: 03/10/2015] [Indexed: 11/15/2022]
Abstract
Myelinated nerve fibers are highly compartmentalized. Helically wrapped lipoprotein membranes of myelin are integrated with subsets of proteins specifically in each compartment to shape the physiological behavior of these nerve fibers. With the advance of molecular biology and genetics, many functions of these proteins have been revealed over the past decade. In this review, we will first discuss how action potential propagation has been understood by classical electrophysiological studies. In particular, the discussion will be concentrated on how the geometric dimensions of myelinated nerve fibers (such as internodal length and myelin thickness) may affect nerve conduction velocity. This discussion will then extend into how specific myelin proteins may shape these geometric parameters, thereby regulating action potential propagation. For instance, periaxin may specifically affect the internodal length, but not other parameters. In contrast, neuregulin-1 may affect myelin thickness, but not axon diameter or internodal length. Finally, we will discuss how these basic neurobiological observations can be applied to inherited peripheral nerve diseases.
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Affiliation(s)
- Jun Li
- Department of Neurology, Center for Human Genetic Research, Vanderbilt Brain Institute, Vanderbilt University School of Medicine, Nashville, TN, USA; Tennessee Valley Healthcare System, Nashville VA, Nashville, TN, USA.
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17
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Drew AP, Zhu D, Kidambi A, Ly C, Tey S, Brewer MH, Ahmad-Annuar A, Nicholson GA, Kennerson ML. Improved inherited peripheral neuropathy genetic diagnosis by whole-exome sequencing. Mol Genet Genomic Med 2015; 3:143-54. [PMID: 25802885 PMCID: PMC4367087 DOI: 10.1002/mgg3.126] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Revised: 11/07/2014] [Accepted: 11/13/2014] [Indexed: 12/31/2022] Open
Abstract
Inherited peripheral neuropathies (IPNs) are a group of related diseases primarily affecting the peripheral motor and sensory neurons. They include the hereditary sensory neuropathies (HSN), hereditary motor neuropathies (HMN), and Charcot-Marie-Tooth disease (CMT). Using whole-exome sequencing (WES) to achieve a genetic diagnosis is particularly suited to IPNs, where over 80 genes are involved with weak genotype–phenotype correlations beyond the most common genes. We performed WES for 110 index patients with IPN where the genetic cause was undetermined after previous screening for mutations in common genes selected by phenotype and mode of inheritance. We identified 41 missense sequence variants in the known IPN genes in our cohort of 110 index patients. Nine variants (8%), identified in the genes MFN2, GJB1, BSCL2, and SETX, are previously reported mutations and considered to be pathogenic in these families. Twelve novel variants (11%) in the genes NEFL, TRPV4, KIF1B, BICD2, and SETX are implicated in the disease but require further evidence of pathogenicity. The remaining 20 variants were confirmed as polymorphisms (not causing the disease) and are detailed here to help interpret sequence variants identified in other family studies. Validation using segregation, normal controls, and bioinformatics tools was valuable as supporting evidence for sequence variants implicated in disease. In addition, we identified one SETX sequence variant (c.7640T>C), previously reported as a putative mutation, which we have confirmed as a nonpathogenic rare polymorphism. This study highlights the advantage of using WES for genetic diagnosis in highly heterogeneous diseases such as IPNs and has been particularly powerful in this cohort where genetic diagnosis could not be achieved due to phenotype and mode of inheritance not being previously obvious. However, first tier testing for common genes in clinically well-defined cases remains important and will account for most positive results.
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Affiliation(s)
- Alexander P Drew
- Northcott Neuroscience Laboratory, ANZAC Research Institute Sydney, Australia
| | - Danqing Zhu
- Molecular Medicine Laboratory, Concord Hospital Sydney, Australia
| | - Aditi Kidambi
- Northcott Neuroscience Laboratory, ANZAC Research Institute Sydney, Australia
| | - Carolyn Ly
- Northcott Neuroscience Laboratory, ANZAC Research Institute Sydney, Australia
| | - Shelisa Tey
- Department of Biomedical Science, Faculty of Medicine, University of Malaya 50603, Kuala Lumpur, Malaysia
| | - Megan H Brewer
- Northcott Neuroscience Laboratory, ANZAC Research Institute Sydney, Australia ; Sydney Medical School, University of Sydney Sydney, Australia
| | - Azlina Ahmad-Annuar
- Department of Biomedical Science, Faculty of Medicine, University of Malaya 50603, Kuala Lumpur, Malaysia
| | - Garth A Nicholson
- Northcott Neuroscience Laboratory, ANZAC Research Institute Sydney, Australia ; Molecular Medicine Laboratory, Concord Hospital Sydney, Australia ; Sydney Medical School, University of Sydney Sydney, Australia
| | - Marina L Kennerson
- Northcott Neuroscience Laboratory, ANZAC Research Institute Sydney, Australia ; Molecular Medicine Laboratory, Concord Hospital Sydney, Australia ; Sydney Medical School, University of Sydney Sydney, Australia
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18
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Liang C, Howells J, Kennerson M, Nicholson GA, Burke D, Ng K. Axonal excitability in X-linked dominant Charcot Marie Tooth disease. Clin Neurophysiol 2014; 125:1261-9. [PMID: 24290847 DOI: 10.1016/j.clinph.2013.11.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2013] [Revised: 10/22/2013] [Accepted: 11/01/2013] [Indexed: 10/26/2022]
Abstract
OBJECTIVE We investigated peripheral nerve function in X-linked Charcot-Marie-Tooth disease type 1 (CMTX1), and considered the functional consequences of mutant connexin-32. METHODS Twelve subjects (9 female, 3 male) were assessed clinically, by nerve conduction and excitability studies. A model of myelinated axon was used to clarify the contributing changes. RESULTS All subjects had abnormal nerve conduction. Excitability studies on median nerve axons showed greater threshold changes to hyperpolarising currents, with "fanning out" in threshold electrotonus, and modest changes in the recovery cycle. Modelling suggested shortening of internodal length, increase in nodal fast potassium currents, shift of the voltage activation hyperpolarisation-activated cyclic-nucleotide-gated channels, and axonal hyperpolarisation. Plotting threshold versus extent of hyperpolarising threshold change in threshold electrotonus distinguished the CMTX1 patients from other chronic demyelinating neuropathies reported in the literature except hereditary neuropathy with pressure palsies (HNPP). CONCLUSIONS Some measures of axonal excitability are similar in CMTX1 and HNPP (though not the recovery cycle), but they differ from those in other chronic demyelinating neuropathies. The findings in CMTX1 are consistent with known pathology, but are not correlated to neuropathy severity. SIGNIFICANCE The findings in CMTX1 could be largely the result of morphological alterations, rather than plasticity in channel expression or distribution.
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Affiliation(s)
- Christina Liang
- Department of Neurology and Clinical Neurophysiology, Royal North Shore Hospital, NSW, Australia; The University of Sydney, NSW, Australia
| | - James Howells
- Institute of Clinical Neurosciences, Royal Prince Alfred Hospital, NSW, Australia; The University of Sydney, NSW, Australia
| | - Marina Kennerson
- ANZAC Research Institute, Concord Repatriation Hospital, NSW, Australia; The University of Sydney, NSW, Australia
| | - Garth A Nicholson
- ANZAC Research Institute, Concord Repatriation Hospital, NSW, Australia; The University of Sydney, NSW, Australia
| | - David Burke
- Institute of Clinical Neurosciences, Royal Prince Alfred Hospital, NSW, Australia; The University of Sydney, NSW, Australia
| | - Karl Ng
- Department of Neurology and Clinical Neurophysiology, Royal North Shore Hospital, NSW, Australia; Institute of Clinical Neurosciences, Royal Prince Alfred Hospital, NSW, Australia; The University of Sydney, NSW, Australia.
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19
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Borgulová I, Mazanec R, Sakmaryová I, Havlová M, Safka Brožková D, Seeman P. Mosaicism for GJB1 mutation causes milder Charcot-Marie-Tooth X1 phenotype in a heterozygous man than in a manifesting heterozygous woman. Neurogenetics 2013; 14:189-95. [PMID: 23912496 DOI: 10.1007/s10048-013-0368-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Accepted: 07/19/2013] [Indexed: 01/11/2023]
Abstract
Charcot-Marie-Tooth (CMT) disease is a heterogeneous disorder of the peripheral nervous system that collectively affects approximately 1 in 2,500 individuals, thus making it the most common inherited neurologic disorder. X-linked inheritance may account for 10-20 % of CMT neuropathy. We report a Czech family with a 30-year-old woman affected by CMT since the age of 10 years, originally as an isolated case. Nerve conduction study (NCS) showed demyelinating neuropathy, and DNA testing revealed a novel heterozygous gap junction beta-1 protein (GJB1) mutation c.784_786delTA. The same mutation, but surprisingly in heterozygous state, was subsequently found in her subjectively healthy father and later also in one of her sisters but not in her two other sisters. NCS showed intermediate type of motor and sensory neuropathy in these two females manifesting heterozygotes and normal results in the other healthy sisters and one brother, all without the c.784_786delTA mutation. The father has a phenotype milder than his daughter and has only subclinical signs of CMT. The index female patient had normal karyotype 46, XX, and normal FISH for centromeric X chromosome. We concluded that the proband's father is a heterozygote due to the somatic mosaicism for the GJB1 mutation in his leukocytes (detected by DNA sequencing) and also in his germ cells as confirmed by the unexpectedly different genotypes in his four daughters. Quantitative analysis revealed a mutated signal in 25:75 allele proportion of mutated to healthy allele in the mosaic father. This study has important consequences for genetic counseling and prognosis in CMTX1 families.
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Affiliation(s)
- I Borgulová
- Centre for Medical Genetics and Reproductive Medicine GENNET, Prague, Czech Republic,
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Pareyson D, Marchesi C, Salsano E. Dominant Charcot-Marie-Tooth syndrome and cognate disorders. HANDBOOK OF CLINICAL NEUROLOGY 2013; 115:817-845. [PMID: 23931817 DOI: 10.1016/b978-0-444-52902-2.00047-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Charcot-Marie-Tooth neuropathy (CMT) is a group of genetically heterogeneous disorders sharing a similar phenotype, characterized by wasting and weakness mainly involving the distal muscles of lower and upper limbs, variably associated with distal sensory loss and skeletal deformities. This chapter deals with dominantly transmitted CMT and related disorders, namely hereditary neuropathy with liability to pressure palsies (HNPP) and hereditary neuralgic amyotrophy (HNA). During the last 20 years, several genes have been uncovered associated with CMT and our understanding of the underlying molecular mechanisms has greatly improved. Consequently, a precise genetic diagnosis is now possible in the majority of cases, thus allowing proper genetic counseling. Although, unfortunately, treatment is still unavailable for all types of CMT, several cellular and animal models have been developed and some compounds have proved effective in these models. The first trials with ascorbic acid in CMT type 1A have been completed and, although negative, are providing relevant information on disease course and on how to prepare for future trials.
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Affiliation(s)
- Davide Pareyson
- Clinics of Central and Peripheral Degenerative Neuropathies Unit, Department of Clinical Neurosciences, IRCCS Foundation, C. Besta Neurological Institute, Milan, Italy.
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21
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Kleopa KA, Abrams CK, Scherer SS. How do mutations in GJB1 cause X-linked Charcot-Marie-Tooth disease? Brain Res 2012; 1487:198-205. [PMID: 22771394 PMCID: PMC3488165 DOI: 10.1016/j.brainres.2012.03.068] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Accepted: 03/24/2012] [Indexed: 11/26/2022]
Abstract
The X-linked form of Charcot-Marie-Tooth disease (CMT1X) is the second most common form of hereditary motor and sensory neuropathy. The clinical phenotype is characterized by progressive weakness, atrophy, and sensory abnormalities that are most pronounced in the distal extremities. Some patients have CNS manifestations. Affected males have moderate to severe symptoms, whereas heterozygous females are usually less affected. Neurophysiology shows intermediate slowing of conduction and length-dependent axonal loss. Nerve biopsies show more prominent axonal degeneration than de/remyelination. Mutations in GJB1, the gene that encodes the gap junction (GJ) protein connexin32 (Cx32) cause CMT1X; more than 400 different mutations have been described. Many Cx32 mutants fail to form functional GJs, or form GJs with abnormal biophysical properties. Schwann cells and oligodendrocytes express Cx32, and the GJs formed by Cx32 play an important role in the homeostasis of myelinated axons. Animal models of CMT1X demonstrate that loss of Cx32 in myelinating Schwann cells causes a demyelinating neuropathy. Effective therapies remain to be developed. This article is part of a Special Issue entitled Electrical Synapses.
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Affiliation(s)
- Kleopas A Kleopa
- Neurology Clinics and Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
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22
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Stauch K, Kieken F, Sorgen P. Characterization of the structure and intermolecular interactions between the connexin 32 carboxyl-terminal domain and the protein partners synapse-associated protein 97 and calmodulin. J Biol Chem 2012; 287:27771-88. [PMID: 22718765 PMCID: PMC3431650 DOI: 10.1074/jbc.m112.382572] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2012] [Revised: 06/20/2012] [Indexed: 12/20/2022] Open
Abstract
In Schwann cells, connexin 32 (Cx32) can oligomerize to form intracellular gap junction channels facilitating a shorter pathway for metabolite diffusion across the layers of the myelin sheath. The mechanisms of Cx32 intracellular channel regulation have not been clearly defined. However, Ca(2+), pH, and the phosphorylation state can regulate Cx32 gap junction channels, in addition to the direct interaction of protein partners with the carboxyl-terminal (CT) domain. In this study, we used different biophysical methods to determine the structure and characterize the interaction of the Cx32CT domain with the protein partners synapse-associated protein 97 (SAP97) and calmodulin (CaM). Our results revealed that the Cx32CT is an intrinsically disordered protein that becomes α-helical upon binding CaM. We identified the GUK domain as the minimal SAP97 region necessary for the Cx32CT interaction. The Cx32CT residues affected by the binding of CaM and the SAP97 GUK domain were determined as well as the dissociation constants for these interactions. We characterized three Cx32CT Charcot-Marie-Tooth disease mutants (R219H, R230C, and F235C) and identified that whereas they all formed functional channels, they all showed reduced binding affinity for SAP97 and CaM. Additionally, we report that in RT4-D6P2T rat schwannoma cells, Cx32 is differentially phosphorylated and exists in a complex with SAP97 and CaM. Our studies support the importance of protein-protein interactions in the regulation of Cx32 gap junction channels and myelin homeostasis.
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Affiliation(s)
- Kelly Stauch
- From the Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska 68198
| | - Fabien Kieken
- From the Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska 68198
| | - Paul Sorgen
- From the Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska 68198
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Arthur-Farraj P, Murphy S, Laura M, Lunn M, Manji H, Blake J, Ramdharry G, Fox Z, Reilly M. Hand weakness in Charcot-Marie-Tooth disease 1X. Neuromuscul Disord 2012; 22:622-6. [PMID: 22464564 PMCID: PMC3657175 DOI: 10.1016/j.nmd.2012.02.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2011] [Revised: 02/14/2012] [Accepted: 02/27/2012] [Indexed: 11/28/2022]
Abstract
There have been suggestions from previous studies that patients with Charcot-Marie-Tooth disease (CMT) have weaker dominant hand muscles. Since all studies to date have included a heterogeneous group of CMT patients we decided to analyse hand strength in 43 patients with CMT1X. We recorded handedness and the MRC scores for the first dorsal interosseous and abductor pollicis brevis muscles, median and ulnar nerve compound motor action potentials and conduction velocities in dominant and non-dominant hands. Twenty-two CMT1X patients (51%) had a weaker dominant hand; none had a stronger dominant hand. Mean MRC scores were significantly higher for first dorsal interosseous and abductor pollicis brevis in non-dominant hands compared to dominant hands. Median nerve compound motor action potentials were significantly reduced in dominant compared to non-dominant hands. We conclude that the dominant hand is weaker than the non-dominant hand in patients with CMT1X.
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Affiliation(s)
- P.J. Arthur-Farraj
- MRC Centre for Neuromuscular Diseases, Department of Molecular Neuroscience, UCL Institute of Neurology and the National Hospital for Neurology and Neurosurgery, Queen Square, London, UK
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Abstract
BACKGROUND Charcot-Marie-Tooth disease (CMT) is the most common inherited disorder of the peripheral nervous system. The frequency of different CMT genotypes has been estimated in clinic populations, but prevalence data from the general population is lacking. Point mutations in the mitofusin 2 (MFN2) gene has been identified exclusively in Charcot-Marie-Tooth disease type 2 (CMT2), and in a single family with intermediate CMT. MFN2 point mutations are probably the most common cause of CMT2. The CMT phenotype caused by mutation in the myelin protein zero (MPZ) gene varies considerably, from early onset and severe forms to late onset and milder forms. The mechanism is not well understood. The myelin protein zero (P(0) ) mediates adhesion in the spiral wraps of the Schwann cell's myelin sheath. X-linked Charcot-Marie Tooth disease (CMTX) is caused by mutations in the connexin32 (cx32) gene that encodes a polypeptide which is arranged in hexameric array and form gap junctions. AIMS Estimate prevalence of CMT. Estimate frequency of Peripheral Myelin Protein 22 (PMP22) duplication and point mutations, insertions and deletions in Cx32, Early growth response 2 (EGR2), MFN2, MPZ, PMP22 and Small integral membrane protein of lysosome/late endosome (SIMPLE) genes. Description of novel mutations in Cx32, MFN2 and MPZ. Description of de novo mutations in MFN2. MATERIAL AND METHODS Our population based genetic epidemiological survey included persons with CMT residing in eastern Akershus County, Norway. The participants were interviewed and examined by one geneticist/neurologist, and classified clinically, neurophysiologically and genetically. Two-hundred and thirty-two consecutive unselected and unrelated CMT families with available DNA from all regions in Norway were included in the MFN2 study. We screened for point mutations in the MFN2 gene. We describe four novel mutations, two in the connexin32 gene and two in the MPZ gene. RESULTS A total of 245 affected from 116 CMT families from the general population of eastern Akershus county were included in the genetic epidemiological survey. In the general population 1 per 1214 persons (95% CI 1062-1366) has CMT. Charcot-Marie-Tooth disease type 1 (CMT1), CMT2 and intermediate CMT were found in 48.2%, 49.4% and 2.4% of the families, respectively. A mutation in the investigated genes was found in 27.2% of the CMT families and in 28.6% of the affected. The prevalence of the PMP22 duplication and mutations in the Cx32, MPZ and MFN2 genes was found in 13.6%, 6.2%, 1.2%, 6.2% of the families, and in 19.6%, 4.8%, 1.1%, 3.2% of the affected, respectively. None of the families had point mutations, insertions or deletions in the EGR2, PMP22 or SIMPLE genes. Four known and three novel mitofusin 2 (MFN2) point mutations in 8 unrelated Norwegian CMT families were identified. The novel point mutations were not found in 100 healthy controls. This corresponds to 3.4% (8/232) of CMT families having point mutations in MFN2. The phenotypes were compatible with CMT1 in two families, CMT2 in four families, intermediate CMT in one family and distal hereditary motor neuronopathy (dHMN) in one family. A point mutation in the MFN2 gene was found in 2.3% of CMT1, 5.5% of CMT2, 12.5% of intermediate CMT and 6.7% of dHMN families. Two novel missense mutations in the MPZ gene were identified. Family 1 had a c.368G>A (Gly123Asp) transition while family 2 and 3 had a c.103G>A (Asp35Asn) transition. The affected in family 1 had early onset and severe symptoms compatible with Dejerine-Sottas syndrome (DSS), while affected in family 2 and 3 had late onset, milder symptoms and axonal neuropathy compatible with CMT2. Two novel connexin32 mutations that cause early onset X-linked CMT were identified. Family 1 had a deletion c.225delG (R75fsX83) which causes a frameshift and premature stop codon at position 247 while family 2 had a c.536G>A (Cys179Tyr) transition which causes a change of the highly conserved cysteine residue, i.e. disruption of at least one of three disulfide bridges. The mean age at onset was in the first decade and the nerve conduction velocities were in the intermediate range. DISCUSSION Charcot-Marie-Tooth disease is the most common inherited neuropathy. At present 47 hereditary neuropathy genes are known, and an examination of all known genes would probably only identify mutations in approximately 50% of those with CMT. Thus, it is likely that at least 30-50 CMT genes are yet to be identified. The identified known and novel point mutations in the MFN2 gene expand the clinical spectrum from CMT2 and intermediate CMT to also include possibly CMT1 and the dHMN phenotypes. Thus, genetic analyses of the MFN2 gene should not be restricted to persons with CMT2. The phenotypic variation caused by different missense mutations in the MPZ gene is likely caused by different conformational changes of the MPZ protein which affects the functional tetramers. Severe changes of the MPZ protein cause dysfunctional tetramers and predominantly uncompacted myelin, i.e. the severe phenotypes congenital hypomyelinating neuropathy and DSS, while milder changes cause the phenotypes CMT1 and CMT2. The two novel mutations in the connexin32 gene are more severe than the majority of previously described mutations possibly due to the severe structural change of the gap junction they encode. CONCLUSION Charcot-Marie-Tooth disease is the most common inherited disorder of the peripheral nervous system with an estimated prevalence of 1 in 1214. CMT1 and CMT2 are equally frequent in the general population. The prevalence of PMP22 duplication and of mutations in Cx32, MPZ and MFN2 is 19.6%, 4.8%, 1.1% and 3.2%, respectively. The ratio of probable de novo mutations in CMT families was estimated to be 22.7%. Genotype- phenotype correlations for seven novel mutations in the genes Cx32 (2), MFN2 (3) and MPZ (2) are described. Two novel phenotypes were ascribed to the MFN2 gene, however further studies are needed to confirm that MFN2 mutations can cause CMT1 and dHMN.
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Affiliation(s)
- G J Braathen
- Head and Neck Research Group, Research Centre, Akershus University Hospital, Lørenskog, Norway.
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Siskind CE, Murphy SM, Ovens R, Polke J, Reilly MM, Shy ME. Phenotype expression in women with CMT1X. J Peripher Nerv Syst 2011; 16:102-7. [PMID: 21692908 DOI: 10.1111/j.1529-8027.2011.00332.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Charcot-Marie-Tooth disease type 1X (CMT1X) is the second most common inherited peripheral neuropathy. Women with CMT1X typically have a less severe phenotype than men, perhaps because of X-inactivation patterns. Our objective was to determine the phenotype of women with CMT1X and whether X-inactivation patterns in white blood cells (WBCs) differ between females with CMT1X and controls. Thirty-one women with CMT1X were evaluated using the CMT neuropathy score (CMTNS) and the CMT symptom score in cross-sectional and longitudinal analyses. Lower scores correspond to less disability. WBCs were analyzed for X-inactivation pattern by androgen receptor X-inactivation assay in 14 patients and 23 controls. The 31 women's mean CMTNS was 8.35. Two-thirds of the cohort had a mild CMTNS (mean 4.85) and one-third had a moderate CMTNS (mean 14.73). Three patients had a CMTNS of 0. The pattern of X-inactivation did not differ between the affected and control groups. Women with CMT1X presented with variable impairment independent of age, type of mutation, or location of mutation. No evidence supported the presence of a gap junction beta-1 (GJB1) mutation affecting the pattern of X-inactivation in blood. Further studies are planned to determine whether X-inactivation is the mechanism for CMT1X females' variable phenotypes.
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Affiliation(s)
- Carly E Siskind
- Department of Neurology, Wayne State University, Detroit, MI 48201, USA.
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Deymeer F, Matur Z, Poyraz M, Battaloglu E, Oflazer-Serdaroglu P, Parman Y. Nerve conduction studies in Charcot-Marie-Tooth disease in a cohort from Turkey. Muscle Nerve 2011; 43:657-64. [DOI: 10.1002/mus.21932] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/04/2010] [Indexed: 11/09/2022]
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Montenegro G, Powell E, Huang J, Speziani F, Edwards YJK, Beecham G, Hulme W, Siskind C, Vance J, Shy M, Züchner S. Exome sequencing allows for rapid gene identification in a Charcot-Marie-Tooth family. Ann Neurol 2011; 69:464-70. [PMID: 21254193 DOI: 10.1002/ana.22235] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Accepted: 08/20/2010] [Indexed: 12/20/2022]
Abstract
OBJECTIVE Charcot-Marie-Tooth (CMT) disease comprises a large number of genetically distinct forms of inherited peripheral neuropathies. The relative uniform phenotypes in many patients with CMT make it difficult to decide which of the over 35 known CMT genes are affected in a given patient. Genetic testing decision trees are therefore broadly based on a small number of major subtypes (eg, CMT1, CMT2) and the observed mutation frequency for CMT genes. Since conventional genetic testing is expensive many rare genes are not being tested for at all. METHODS Whole-exome sequencing has recently been introduced as a novel and alternative approach. This method is capable of resequencing a nearly complete set of coding exons in an individual. We performed whole-exome sequencing in an undiagnosed family with CMT. RESULTS Within over 24,000 variants detected in 2 exomes of a CMT family, we identified a nonsynonymous GJB1 (Cx32) mutation. This variant had been reported previously as pathogenic in X-linked CMT families. Sanger sequencing confirmed complete cosegregation in the family. Affected individuals had a marked early involvement of the upper distal extremities and displayed a mild reduction of nerve conduction velocities. INTERPRETATION We have shown for the first time in a genetically highly heterogeneous dominant disease that exome sequencing is a valuable method for comprehensive medical diagnosis. Further improvements of exon capture design, next-generation sequencing accuracy, and a constant price decline will soon lead to the adoption of genomic approaches in gene testing of Mendelian disease.
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Affiliation(s)
- Gladys Montenegro
- John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, FL 33136, USA
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Brozková D, Mazanec R, Haberlová J, Sakmaryová I, Subrt I, Seeman P. Six new gap junction beta 1 gene mutations and their phenotypic expression in Czech patients with Charcot-Marie-Tooth disease. Genet Test Mol Biomarkers 2010; 14:3-7. [PMID: 20039784 DOI: 10.1089/gtmb.2009.0093] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
X-linked Charcot-Marie-Tooth (CMTX) disease is a hereditary motor and sensory neuropathy caused by mutations in the gap junction beta 1 gene (GJB1 codes for connexin 32). In this study we report six novel mutations p.Met1Arg, p.Leu9Phe, p.Ser17Tyr, p.Val63Phe, p.Val170Ile, and p.Leu212Phe in GJB1 and their phenotypic expression. These mutations affect both intracellular and extracellular parts of the GJB1 protein. The screened patients had previously excluded the duplication/deletion on 17p11.2 and the male-to-male transfer in the pedigree. Except p.Val170Ile, all reported mutations segregated with the CMT phenotype in the families and caused CMTX1 neuropathy. Mutations were not found in 200 control DNA samples. Additionally, we performed in silico analysis of the novel mutations with the program PANTHER. The PANTHER scored five mutations, all but p.Val170Ile, as likely deleterious and supported the pathogenicity of the found mutations. These results provided evidence that these five mutations are causative for CMTX1.
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Affiliation(s)
- Dana Brozková
- DNA Laboratory, Department of Child Neurology, Charles University 2nd Medical School and University Hospital Motol, Prague, Czech Republic.
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Kleopa KA, Orthmann-Murphy J, Sargiannidou I. Gap Junction Disorders of Myelinating Cells. Rev Neurosci 2010; 21:397-419. [DOI: 10.1515/revneuro.2010.21.5.397] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Li M, Cheng TS, Ho PWL, Chan KH, Mak W, Cheung RTF, Ramsden DB, Sham PC, Song Y, Ho SL. -459C>T point mutation in 5' non-coding region of human GJB1 gene is linked to X-linked Charcot-Marie-Tooth neuropathy. J Peripher Nerv Syst 2009; 14:14-21. [PMID: 19335535 DOI: 10.1111/j.1529-8027.2009.00201.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Charcot-Marie-Tooth (CMT) neuropathy is inherited with genetic and clinical heterogeneity. The X-linked form (CMTX) is linked to mutations in the GJB1 gene. However, the genotype-phenotype correlation between variants in the non-coding region of GJB1 gene and CMTX is unclear. We found two structural variants (-459C>T and -713G>A) in the 5' non-coding region of a transcript (Ref seq ID: NM_000166) of the GJB1 gene and explored its association with CMTX in two Chinese families. All family members who carried the -459C>T variant either were symptomatic or had abnormal electrophysiological studies compatible with CMTX, whereas all the non-symptomatic family members who had normal electrophysiological studies and 10 healthy unrelated controls did not have this variant. The other variant in the 5'-flanking region of the gene was found to be a benign polymorphism, although it had been earlier reported to be associated with CMTX in a Taiwanese family. Secondary structure prediction analysis of mutant mRNA using M fold and RNA structure softwares indicates that the -459C>T mutation may reduce translation efficiency of the GJB1 gene by changing its 5'-untranslated region secondary structure and abolishing the internal ribosome entry site at the initialization of its translation in Schwann cells. Our study can help clarify the causal mutations of CMTX in the non-protein coding region of GJB1.
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Affiliation(s)
- Miaoxin Li
- Department of Biochemistry, University of Hong Kong, Hong Kong, China
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Baker SK, Reith CC, Ainsworth PJ. Novel 95G>A (R32K) somatic mosaic connexin 32 mutation. Muscle Nerve 2008; 38:1510-1514. [PMID: 18949782 DOI: 10.1002/mus.21145] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
Charcot-Marie-Tooth disease (CMT) is among the most common inherited disorders of the peripheral nervous system, and it is broadly categorized as demyelinating type 1 or axonal type 2 based on nerve conduction studies. Mutations in discrete genes usually segregate into a single phenotype. However, mutations in connexin 32 (Cx32) can produce both axonal and demyelinating CMT phenotypes. Although over 300 mutations have been described in Cx32, somatic mosaicism has only been reported once previously. We report a 39-year-old man who was referred for electrodiagnostic evaluation due to a history of bilateral carpal tunnel syndrome. His physical examination and electrodiagnostic findings demonstrated a mild sensorimotor axonal peripheral neuropathy. Sequencing of his Cx32 (GJB1) gene identified a guanine-to-adenine (G>A) transition at nucleotide position 95. This transition mutation involved approximately one-third of leukocyte-derived genomic DNA. This is the second reported case of somatic mosaicism, and it highlights the phenotypic diversity among CMTX patients.
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Affiliation(s)
- Steven K Baker
- Department of Medicine, Division of Neurology, Neuromuscular Disease Clinic, McMaster University Medical Center, 120 Main Street West, Hamilton, Ontario L8N 3Z5, Canada
| | - Cara C Reith
- Department of Pathology, London Health Sciences Center, University of Western Ontario, London, Ontario, Canada
- Department of Biochemistry, London Health Sciences Center, University of Western Ontario, London, Ontario, Canada
| | - Peter J Ainsworth
- Department of Pathology, London Health Sciences Center, University of Western Ontario, London, Ontario, Canada
- Department of Biochemistry, London Health Sciences Center, University of Western Ontario, London, Ontario, Canada
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Khidiyatova IM, Bagautdinova EG, Galieva DV, Krupina NB, Shchagina OA, Tiburkova TB, Magzhanov RV, Polyakov AV, Khusnutdinova EK. Spectrum and frequency of mutations in the connexin 32 gene (GJB1) in hereditary and sensory neuropathy type 1X patients from Bashkortostan. RUSS J GENET+ 2008. [DOI: 10.1134/s1022795408100098] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Vital A, Ferrer X, Lagueny A, Vandenberghe A, Latour P, Goizet C, Canron MH, Louiset P, Petry KG, Vital C. Histopathological features of X-linked Charcot-Marie-Tooth disease in 8 patients from 6 families with different connexin32 mutations. J Peripher Nerv Syst 2008. [DOI: 10.1111/j.1529-8027.2001.01011.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Nave KA, Sereda MW, Ehrenreich H. Mechanisms of disease: inherited demyelinating neuropathies--from basic to clinical research. ACTA ACUST UNITED AC 2007; 3:453-64. [PMID: 17671523 DOI: 10.1038/ncpneuro0583] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2007] [Accepted: 05/25/2007] [Indexed: 01/30/2023]
Abstract
The hereditary motor and sensory neuropathies (also known as Charcot-Marie-Tooth disease or CMT) are characterized by a length-dependent loss of axonal integrity in the PNS, which leads to progressive muscle weakness and sensory deficits. The 'demyelinating' neuropathies (CMT disease types 1 and 4) are genetically heterogeneous, but their common feature is that the primary defect perturbs myelination. As we discuss in this Review, several new genes associated with CMT1 and CMT4 have recently been identified. The emerging view is that a range of different subcellular defects in Schwann cells can cause axonal loss, which represents the final common pathway of all CMT disease and is independent of demyelination. We propose that Schwann cells provide a first line of axonal neuroprotection. A better understanding of axon-glia interactions should open the way to therapeutic interventions for demyelinating neuropathies. Transgenic animal models have become essential for dissecting CMT disease mechanisms and exploring novel therapies.
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Affiliation(s)
- Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany.
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Braathen GJ, Sand JC, Bukholm G, Russell MB. Two novel connexin32 mutations cause early onset X-linked Charcot-Marie-Tooth disease. BMC Neurol 2007; 7:19. [PMID: 17620124 PMCID: PMC1999495 DOI: 10.1186/1471-2377-7-19] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2007] [Accepted: 07/09/2007] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND X-linked Charcot-Marie Tooth (CMT) is caused by mutations in the connexin32 gene that encodes a polypeptide which is arranged in hexameric array and form gap junctions. METHODS We describe two novel mutations in the connexin32 gene in two Norwegian families. RESULTS Family 1 had a c.225delG (R75fsX83) which causes a frameshift and premature stop codon at position 247. This probably results in a shorter non-functional protein structure. Affected individuals had an early age at onset usually in the first decade. The symptoms were more severe in men than women. All had severe muscle weakness in the legs. Several abortions were observed in this family. Family 2 had a c.536 G>A (C179Y) transition which causes a change of the highly conserved cysteine residue, i.e. disruption of at least one of three disulfide bridges. The mean age at onset was in the first decade. Muscle wasting was severe and correlated with muscle weakness in legs. The men and one woman also had symptom from their hands. The neuropathy is demyelinating and the nerve conduction velocities were in the intermediate range (25-49 m/s). Affected individuals had symmetrical clinical findings, while the neurophysiology revealed minor asymmetrical findings in nerve conduction velocity in 6 of 10 affected individuals. CONCLUSION The two novel mutations in the connexin32 gene are more severe than the majority of previously described mutations possibly due to the severe structural change of the gap junction they encode.
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Affiliation(s)
- Geir J Braathen
- Faculty Division Akershus University Hospital, University of Oslo, 1474 Nordbyhagen, Oslo, Norway
- Institute for clinical epidemiology and molecular biology (Epi-Gen), Akershus University Hospital, 1478 Lørenskog, Oslo, Norway
- Department of Laboratory Medicine, Genetic section, Telemark Hospital, 3710 Skien, Norway
- Department of Neurology, Akershus University Hospital, 1478 Lørenskog, Oslo, Norway
| | - Jette C Sand
- Institute for clinical epidemiology and molecular biology (Epi-Gen), Akershus University Hospital, 1478 Lørenskog, Oslo, Norway
| | - Geir Bukholm
- Faculty Division Akershus University Hospital, University of Oslo, 1474 Nordbyhagen, Oslo, Norway
- Institute for clinical epidemiology and molecular biology (Epi-Gen), Akershus University Hospital, 1478 Lørenskog, Oslo, Norway
- Department of Research and Development, Akershus University Hospital, 1478 Lørenskog, Oslo, Norway
| | - Michael B Russell
- Faculty Division Akershus University Hospital, University of Oslo, 1474 Nordbyhagen, Oslo, Norway
- Department of Neurology, Akershus University Hospital, 1478 Lørenskog, Oslo, Norway
- Department of Research and Development, Akershus University Hospital, 1478 Lørenskog, Oslo, Norway
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Shy ME, Siskind C, Swan ER, Krajewski KM, Doherty T, Fuerst DR, Ainsworth PJ, Lewis RA, Scherer SS, Hahn AF. CMT1X phenotypes represent loss of GJB1 gene function. Neurology 2007; 68:849-55. [PMID: 17353473 DOI: 10.1212/01.wnl.0000256709.08271.4d] [Citation(s) in RCA: 121] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To investigate possible genotype-phenotype correlations and to evaluate the natural history of patients with Charcot-Marie-Tooth disease type 1X (CMT1X). BACKGROUND CMT1X is caused by over 260 distinct mutations in the gap junction beta 1 (GJB1) gene, located on the X chromosome, which encodes the gap junction protein connexin 32 (Cx32). The natural history of CMT1X is poorly understood, and it remains unknown whether particular mutations cause more severe neuropathies through abnormal gain-of-function mechanisms. METHODS We evaluated 73 male patients with CMT1X, who each have 1 of 28 different GJB1 mutations predicted to affect nearly all domains of Cx32. Disability was evaluated quantitatively by the CMT Neuropathy Score (CMTNS) as well as by the CMT Symptom Score (CMTSS) and the CMT Examination Score (CMTES), which are both based on the CMTNS. Patients were also evaluated by neurophysiology. RESULTS In all patients, disability increased with age, and the degree of disability was comparable with that observed in patients with a documented GJB1 deletion. Disability correlated with a loss of motor units as assessed by motor unit number estimates. CONCLUSIONS Taken together, these data suggest that most GJB1 mutations cause neuropathy by a loss of normal connexin 32 function. Therefore, treatment of male patients with Charcot-Marie-Tooth disease type 1X may prove amenable to gene replacement strategies.
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Affiliation(s)
- M E Shy
- Department of Neurology, Wayne State University, 421 E. Canfield, Detroit, MI 48201, USA.
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Abstract
Neuropathy is one of the most common referrals to neurologic clinics. Patients often undergo extensive testing for acquired etiologies; inherited causes are common. Increasingly, genetic causes are becoming known and commercial testing available. The rate of recent discovery has been rapid and relates to the extent of single gene disorders of nerve, the ease of peripheral nervous system functional examination, and readily accessible pathologic tissue. Foremost in the rate of recent discoveries is the work and tools of the human genome project. the rapidity of the ongoing discovery requires clinicians to be familiar with molecular biologic discoveries and consider wisely which testing should be performed.
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Affiliation(s)
- Christopher J Klein
- Department of Neurology, Division of Peripheral Nerve Diseases, Mayo Clinic, Rochester, MN, USA.
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38
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Ouvrier R, Geevasingha N, Ryan MM. Autosomal-recessive and X-linked forms of hereditary motor and sensory neuropathy in childhood. Muscle Nerve 2007; 36:131-43. [PMID: 17410579 DOI: 10.1002/mus.20776] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The hereditary motor and sensory neuropathies (HMSNs, Charcot-Marie-Tooth neuropathies) are the most common degenerative disorders of the peripheral nervous system. In recent years a dramatic expansion has occurred in our understanding of the molecular basis and cell biology of the recessively inherited demyelinating and axonal neuropathies, with delineation of a number of new neuropathies. Mutations in some genes cause a wide variety of clinical, neurophysiologic, and pathologic phenotypes, rendering diagnosis difficult. The X-linked forms of HMSN represent at least 10%-15% of all HMSNs and have an expanded disease spectrum including demyelinating, intermediate, and axonal neuropathies, transient central nervous system (CNS) dysfunction, mental retardation, and hearing loss. This review presents an overview of the recessive and X-linked forms of HMSN observed in childhood, with particular reference to disease phenotype and neurophysiologic and pathologic abnormalities suggestive of specific diagnoses. These findings can be used by the clinician to formulate a differential diagnosis and guide targeted genetic testing.
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Affiliation(s)
- Robert Ouvrier
- TY Nelson Department of Neurology and Neurosurgery, Children's Hospital at Westmead, Locked Bag 4001, Westmead, NSW 2145, Australia.
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Huttner IG, Kennerson ML, Reddel SW, Radovanovic D, Nicholson GA. Proof of genetic heterogeneity in X-linked Charcot-Marie-Tooth disease. Neurology 2006; 67:2016-21. [PMID: 17159110 DOI: 10.1212/01.wnl.0000247271.40782.b7] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
OBJECTIVE To characterize a large family with X-linked Charcot-Marie-Tooth (CMT) neuropathy without mutations in the gap junction protein B1 (GJB1) gene, which has an unusual phenotype that is different in some aspects from classic CMTX1. METHODS We tested CMT families consistent with X-linked inheritance for GJB1 mutations. We compared the largest family (CMT623) without GJB1 mutation and with linkage excluding the CMTX1 locus to CMTX1 and normal individuals. RESULTS Only 51% of probable X-linked CMT families had mutations in GJB1. Family CMT623 shows linkage to Xq26.3-q27.1 (lod score z = 6.58), a region within the previously identified locus for CMTX3, Xq26-q28. Unlike CMTX1, affected males in family CMT623 report pain and paraesthesia before the onset of sensory loss, and women are usually asymptomatic. As in CMTX1, affected males have widely ranging intermediate motor conduction velocities. The coding regions of 14 positional candidate genes within the narrowed CMTX3 locus have been excluded for a pathogenic role in the disease. CONCLUSION This study is the first to confirm the CMTX3 locus and to refine the genetic interval to a 5.7-Mb region flanked by the markers DXS1041 and DXS8106. GJB1 mutation-negative forms of X-linked CMT, such as CMTX3, may account for a significant proportion of X-linked CMT.
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Affiliation(s)
- I G Huttner
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Australia
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Abstract
Charcot-Marie-Tooth disease (CMT) is the most common form of inherited motor and sensory neuropathy. Moreover, CMT is a genetically heterogeneous disorder of the peripheral nervous system, with many genes identified as CMT-causative. CMT has two usual classifications: type 1, the demyelinating form (CMT1); and type 2, the axonal form (CMT2). In addition, patients are classified as CMTX if they have an X-linked inheritance pattern and CMT4 if the inheritance pattern is autosomal recessive. A large amount of new information on the genetic causes of CMT has become available, and mutations causing it have been associated with more than 17 different genes and 25 chromosomal loci. Advances in our understanding of the molecular basis of CMT have revealed an enormous diversity in genetic mechanisms, despite a clinical entity that is relatively uniform in presentation. In addition, recent encouraging studies - shown in CMT1A animal models - concerning the therapeutic effects of certain chemicals have been published; these suggest potential therapies for the most common form of CMT, CMT1A. This review focuses on the inherited motor and sensory neuropathy subgroup for which there has been an explosion of new molecular genetic information over the past decade.
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Affiliation(s)
- Jung-Hwa Lee
- Department of Neurology and Ewha Medical Research Center, College of Medicine, Ewha Womans University, Seoul, Korea
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Pareyson D, Scaioli V, Laurà M. Clinical and electrophysiological aspects of Charcot-Marie-Tooth disease. Neuromolecular Med 2006; 8:3-22. [PMID: 16775364 DOI: 10.1385/nmm:8:1-2:3] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2005] [Revised: 12/06/2005] [Accepted: 12/15/2005] [Indexed: 11/11/2022]
Abstract
Charcot-Marie-Tooth disease (CMT) is a genetically heterogeneous group of disorders sharing the same clinical phenotype, characterized by distal limb muscle wasting and weakness, usually with skeletal deformities, distal sensory loss, and abnormalities of deep tendon reflexes. Mutations of genes involved in different functions eventually lead to a length-dependent axonal degeneration, which is the likely basis of the distal predominance of the CMT phenotype. Nerve conduction studies are important for classification, diagnosis, and understanding of pathophysiology. The subdivision into demyelinating CMT1 and axonal CMT2 types was a milestone and is still valid for the majority of patients. However, exceptions to this partition are increasing. Intermediate conduction velocities are often found in males with X-linked CMT (CMTX), and different intermediate CMT types have been identified. Moreover, for some genes, different mutations may result either in demyelinating CMT with slow conduction, or in axonal CMT. Nerve conduction slowing is uniform and diffuse in the most common CMT1A associated with the 17p12 duplication, whereas it is often asymmetric and nonhomogeneous in CMTX, sometimes rendering difficult the differential diagnosis with acquired inflammatory neuropathies. The demyelinating recessive forms, termed CMT4, usually have early onset and run a more severe course than the dominant types. Pure motor CMT types are now classified as distal hereditary motor neuronopathy. The diagnostic approach to the identification of the CMT subtype is complex and cannot be based on the clinical phenotype alone, as different forms are often clinically indistinguishable. However, there are features that may be of help in addressing molecular investigation in a single patient. Late onset, prominent or peculiar sensory manifestations, autonomic nervous system dysfunction, cranial nerve involvement, upper limb predominance, subclinical central nervous system abnormalities, severe scoliosis, early-onset glaucoma, neutropenia are findings helpful for diagnosis.
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Affiliation(s)
- D Pareyson
- Division of Biochemistry and Genetics, Carlo Besta National Neurological Institute, via Celoria, 11, 20133, Milan, Italy.
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Kleopa KA, Zamba-Papanicolaou E, Alevra X, Nicolaou P, Georgiou DM, Hadjisavvas A, Kyriakides T, Christodoulou K. Phenotypic and cellular expression of two novel connexin32 mutations causing CMT1X. Neurology 2006; 66:396-402. [PMID: 16476939 DOI: 10.1212/01.wnl.0000196479.93722.59] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To determine the phenotypic and cellular expression of two novel connexin32 (Cx32) mutations causing X-linked Charcot-Marie-Tooth disease (CMT1X). METHODS The authors evaluated several members of two families with CMT1X clinically, electrophysiologically, pathologically, and by genetic testing. The Cx32 mutations were expressed in vitro and studied by immunocytochemistry. RESULTS In both families, men were more severely affected than women with onset in the second decade of life. In the first family, the phenotype was that of demyelinating polyneuropathy with variable involvement of peripheral nerves. There was clinical evidence of CNS involvement in at least three of the patients, with extensor plantar responses and brisk reflexes. In the second family, the affected man presented with symmetric polyneuropathy and intermediate slowing of conduction velocities, whereas affected women had prominent asymmetric atrophy of the leg muscles. The authors identified two novel missense mutations resulting in L143P amino acid substitution in the first family and in V140E substitution in the second family, both located in the third transmembrane domain of Cx32. Expression of these Cx32 mutations in communication-incompetent HeLa cells and immunocytochemical analysis revealed that both mutants were retained intracellularly and were localized in the Golgi apparatus. In contrast to wild-type protein, they did not form gap junctions. CONCLUSION These novel connexin32 (Cx32) mutations cause a spectrum of clinical manifestations characteristic of Charcot-Marie-Tooth disease (CMT1X), including demyelinating or intermediate polyneuropathy, which is often asymmetric, and CNS involvement in one family. The position and cellular expression of Cx32 mutations alone cannot fully predict these phenotypic variations in CMT1X.
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Affiliation(s)
- K A Kleopa
- Department of Clinical Neurosciences, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus.
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Kleopa KA, Scherer SS. Molecular genetics of X-linked Charcot-Marie-Tooth disease. Neuromolecular Med 2006; 8:107-22. [PMID: 16775370 DOI: 10.1385/nmm:8:1-2:107] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2005] [Revised: 11/10/2005] [Accepted: 11/17/2005] [Indexed: 11/11/2022]
Abstract
The X-linked form of Charcot-Marie-Tooth disease (CMT1X) is the second most common molecularly designated form of hereditary motor and sensory neuropathy. The clinical phenotype is characterized by progressive distal muscle atrophy and weakness, areflexia, and variable sensory abnormalities. Affected males have moderate-to-severe symptoms, whereas heterozygous females are usually mildly affected or even asymptomatic. Several patients also have manifestations of central nervous system involvement or hearing impairment. Electrophysiological and pathological studies of peripheral nerves show evidence of demyelinating neuropathy with prominent axonal degeneration. A large number of mutations in the GJB1 gene encoding the gap junction (GJ) protein connexin32 (Cx32) cause CMT1X. Cx32 is expressed by Schwann cells and oligodendrocytes, as well as by other tissues, and the GJ formed by Cx32 play an important role in the homeostasis of myelinated axons. The reported CMT1X mutations are diverse and affect both the promoter region as well as the coding region of GJB1. Many Cx32 mutants fail to form functional GJ, or form GJ with abnormal biophysical properties. Furthermore, Cx32 mutants are often retained intracellularly either in the endoplasmic reticulum or Golgi in which they could potentially have additional dominant-negative effects. Animal models of CMT1X demonstrate that loss of Cx32 in myelinating Schwann cells causes a demyelinating neuropathy. No definite phenotype-genotype correlation has yet been established for CMT1X and effective molecular based therapeutics for this disease, remain to be developed.
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Affiliation(s)
- Kleopas A Kleopa
- Department of Clinical Neurosciences, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus.
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Beauvais K, Furby A, Latour P. Clinical, electrophysiological and molecular genetic studies in a family with X-linked dominant Charcot-Marie-Tooth neuropathy presenting a novel mutation in GJB1 Promoter and a rare polymorphism in LITAF/SIMPLE. Neuromuscul Disord 2006; 16:14-8. [PMID: 16373087 DOI: 10.1016/j.nmd.2005.09.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2005] [Accepted: 09/20/2005] [Indexed: 11/28/2022]
Abstract
Charcot-Marie-Tooth disease is a genetically heterogeneous group of neuropathies. In the demyelinating form of Charcot-Marie-Tooth disease with dominant inheritance, five genes have been incriminated: PMP22, MPZ, LITAF/SIMPLE, EGR2 (CMT1A to D), and GJB1 (CMTX). Here, we report clinical, electrophysiological and molecular genetic studies in a family with a Charcot-Marie-Tooth disease variable phenotype, ranging from asymptomatic to moderately affected. The absence of male-to-male transmission as well as the results of systematic electrophysiological studies suggested a CMTX secondary to a GJB1 mutation. Screening for mutations in the coding regions of PMP22, MPZ, EGR2 and GJB1 was negative. We identified (1) a LITAF/SIMPLE substitution (T49M), absent in 1000 control chromosomes, but which was thought to be a polymorphism because of discrepancies of segregation when considering the results of electrophysiology; and (2) a novel substitution T>C in the P2 promoter of GJB1 at position -529, in the SOX10 binding site S2. The transmission of this second mutation was consistent with the electrophysiological data. We emphasise the role of electrophysiological studies that help to discriminate between asymptomatic subjects and that bring some additional valuable data to the genetic approach.
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Affiliation(s)
- Katell Beauvais
- Unité de Neurophysiologie Clinique, Hôpital Yves Le Foll, 22023 Saint-Brieuc, France
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Carvalho AAS, Vital A, Ferrer X, Latour P, Lagueny A, Brechenmacher C, Vital C. Charcot-Marie-Tooth disease type 1A: clinicopathological correlations in 24 patients. J Peripher Nerv Syst 2005; 10:85-92. [PMID: 15703022 DOI: 10.1111/j.1085-9489.2005.10112.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
We examined nerve biopsies from 24 patients with Charcot-Marie-Tooth disease type 1A (CMT1A) and proven 17p11.2-12 duplication. There were seven males and 17 females with a mean age of 27.85 +/- 18.95 years at the time of nerve biopsy. A family history consistent with dominant inheritance was present in 17 patients. Clinical features were classical in 16 patients and were atypical in the other eight: one had calf hypertrophy; two had Roussy-Levy syndrome; one had had a subacute inflammatory demyelinating polyneuropathy 11 years earlier and presented a relapse on the form of a chronic inflammatory demyelinating polyneuropathy; one had carpal tunnel syndrome; one had a recent painful neuropathy in both legs; and two had chronic inflammatory demyelinating polyneuropathy. Onion bulb formations (OMFs) were present in every case and most of them were characteristic, whereas burnt-out or cluster-associated OMFs were less common. Depletion of myelinated fibers was severe in 20 cases (169-2927/mm2) and varied from 5187 to 3725/mm2 in three children (4-9 years old). In addition, features of macrophage-associated demyelination were observed in the last four atypical cases. Known for more than 20 years, inflammatory demyelination superimposed in the course of CMT1A has been reported in a few cases in the past few years, mainly concerning asymptomatic or atypical patients. Such an association deserves to be better known because corticotherapy improves weakness in most of these patients.
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Affiliation(s)
- Alzira A S Carvalho
- Neuropathology Department, Victor Segalen University, Pessac, Bordeaux, France
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Correa PRAV, Guerra MT, Leite MF, Spray DC, Nathanson MH. Endotoxin unmasks the role of gap junctions in the liver. Biochem Biophys Res Commun 2004; 322:718-26. [PMID: 15336523 DOI: 10.1016/j.bbrc.2004.07.192] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2004] [Indexed: 10/26/2022]
Abstract
Gap junctions are thought to be necessary for proper tissue function. However, no clear hepatic phenotype has been described in patients lacking connexin 32 (Cx32), the principal gap junction in liver. To determine the physiological role of Cx32 in liver, we compared the response of wild type and Cx32-deficient mice to endotoxin, since this stress increases serum levels of hormones that bind to receptors that are asymmetrically distributed across the hepatic lobule. In hepatocyte couplets isolated from wild type mice, most hepatocytes could transfer microinjected dye to their neighbor even after treatment with endotoxin. Dye transfer was not observed in Cx32-deficient couplets. Treatment of hepatocyte couplets from wild type mice with vasopressin induced calcium (Ca(2+)) waves that crossed the couplets in a concentration-dependent fashion, but the delay in transmission was markedly prolonged at all concentrations in Cx32-deficient couplets. Expression of the vasopressin receptor and the inositol 1,4,5-trisphosphate receptor was not decreased by endotoxin or in Cx32-deficient couplets. Finally, endotoxin caused transient hypoglycemia and cholestasis in wild type animals, but hypoglycemia was slightly prolonged and cholestasis was much worse in Cx32-deficient mice treated with endotoxin. The hepatic response to endotoxin is markedly impaired in the absence of Cx32. Thus, an important role of gap junctions in the liver is to assure integrated and uniform tissue response in times of stress.
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Affiliation(s)
- Paulo R A V Correa
- Department of Medicine, Yale University School of Medicine, New Haven, CT, USA
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Abstract
The mechanisms underlying normal and abnormal cardiac rhythms are complex and incompletely understood. Through the study of uncommon inheritable arrhythmia syndromes, including the long QT and Brugada syndromes, new insights are emerging. At the cellular and tissue levels, we now recognize that ion channel current is the sum of biophysical (gating, permeation), biochemical (phosphorylation, etc), and biogenic (biosynthesis, processing, trafficking, and degradation) properties. This review focuses on how heart cells process ion channel proteins and how this protein trafficking may be altered in some cardiac arrhythmia diseases. In this review, we honor Dr Harry A. Fozzard, a modern pioneer in cardiac arrhythmias, cell biology, and molecular electrophysiology. As a scientist and physician, his writings and mentorship have served to foster a generation of investigators who continue to bring this complex field toward greater scientific understanding and impact on humankind.
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Affiliation(s)
- Brian P Delisle
- Section of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison, USA
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Pouget J. [Molecular diagnosis of hereditary neuropathies such as Charcot-Marie-Tooth disease]. Rev Neurol (Paris) 2004; 160:181-7. [PMID: 15034475 DOI: 10.1016/s0035-3787(04)70889-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
During the last decade, molecular biology has demonstrated the extraordinary heterogeneity of genetic abnormalities in Charcot-Marie-Tooth disease (CMT). The main phenotypes are either of the demyelinating or axonal type, transmitted with dominant or recessive autosomal inheritance. X-linked CMT is less rare than it was initially described and is often misdiagnosed as autosomal dominant type. Linked phenotypes are Dejerine-Sottas disease, congenital hypomyelinization and hereditary neuropathy with susceptibility to pressure palsies. Each phenotype can be due to different genotypes and concerned genes are numerous. Conversely, each genotype can express different phenotypes. Molecular diagnostic strategy of CMT is mainly baised on three elements: - phenotypic expertise which is based on the analysis of the inheritance mode and on electrophysiological data, which are peculiar in CMTX - knowledge of respective occurrence of the different genotypes and phenotypes which is increasing - technical feasibility of molecular biology methods which is important to consider, even though progress are fastly coming. According to these considerations, a strategy is proposed for molecular diagnosis of CMT.
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Affiliation(s)
- J Pouget
- Service de Neurologie et maladies neuromusculaires, Hôpital Universitaire de La Timone, Marseille
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Capasso M, Di Muzio A, Ferrarini M, De Angelis MV, Caporale CM, Lupo S, Cavallaro T, Fabrizi GM, Uncini A. Inter-nerves and intra-nerve conduction heterogeneity in CMTX with Arg(15)Gln mutation. Clin Neurophysiol 2004; 115:64-70. [PMID: 14706470 DOI: 10.1016/j.clinph.2003.08.024] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
OBJECTIVE In X-linked Charcot-Marie-Tooth disease (CMTX), electrophysiological and histopathological studies have suggested either a demyelinating or an axonal polyneuropathy. We report a CMTX family with a striking heterogeneity of nerve conductions between and within nerves. METHODS Two men and one woman have been studied by conduction velocities, sural nerve biopsy with morphometry (one man) and DNA analysis. RESULTS In both men motor conduction velocities were slowed in the demyelinating range, conduction velocity differences among nerves in the same subject varied from 13 to 24 m/s, and distal median compound muscle action potential (CMAP) amplitudes were 3-5 times reduced compared to ulnar CMAPs. Abnormal area reduction or excessive temporal dispersion of proximal CMAP was present in at least two nerves in all patients. Sural nerve biopsy showed reduction of large myelinated fibres, cluster formations, occasional onion bulbs. Teased fibres study revealed short internodes for fibre diameter, enlarged Ranvier nodes but no evidence of segmental demyelination and remyelination. DNA analysis showed an Arg(15)Gln mutation in connexin32 gene in all patients. CONCLUSIONS In this family conduction slowing and segmental conduction abnormalities, in absence of morphological evidence of de-remyelination, may be related to short internodes, widened Ranvier nodes and the specific effect of the mutation. The occurrence in some CMTX patients of a non uniform involvement between and within nerves, as in acquired demyelinating neuropathies, should be kept in mind to avoid misdiagnoses.
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Affiliation(s)
- M Capasso
- Neurodegenerative Diseases Unit, Institute of Aging, University G. d'Annunzio, Ospedale SS. Annunziata, Via dei Vestini, I-66013 Chieti, Italy
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Lewis RA, Li J, Fuerst DR, Shy ME, Krajewski K. Motor unit number estimate of distal and proximal muscles in Charcot-Marie-Tooth disease. Muscle Nerve 2003; 28:161-7. [PMID: 12872319 DOI: 10.1002/mus.10419] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In order to determine the utility of motor unit number estimation (MUNE) in assessing axonal loss in chronic inherited neuropathies, we determined MUNEs in 54 patients with Charcot-Marie-Tooth (CMT) disease (29 patients with CMT-1A, 13 with CMT-X, and 12 with CMT-2) by using spike-triggered averaging (STA) of the ulnar-innervated abductor digiti minimi/hypothenar muscles (ADM) and the musculo-cutaneous innervated biceps/brachialis (BB) muscles. MUNEs were analyzed in relationship to the corresponding compound muscle action potential (CMAP) amplitudes as well as to clinical strength. Proximal muscles, which appeared strong clinically, had evidence of chronic denervation/reinnervation, although to a lesser extent than weak distal hand muscles, supporting the concept that axonal loss in CMT occurs in a length-dependent fashion. The reduction in ADM-MUNE strongly correlated with clinical weakness in the hand. Both the ADM-MUNE and BB-MUNE were abnormal more often than CMAP amplitude, probably reflecting extensive motor unit reconfiguration and enlargement that maintains CMAP amplitude despite severe motor unit loss. This study suggests that MUNE can assess motor unit loss in CMT and may better reflect axonal loss than CMAP amplitude. The STA technique of MUNE may be useful in longitudinal studies of proximal and distal motor unit changes in CMT.
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Affiliation(s)
- Richard A Lewis
- Department of Neurology, Wayne State University School of Medicine, 4201 St Antoine, Detroit, Michigan 48201, USA.
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