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Uncini A, Cavallaro T, Fabrizi GM, Manganelli F, Vallat JM. Conduction slowing, conduction block and temporal dispersion in demyelinating, dysmyelinating and axonal neuropathies: Electrophysiology meets pathology. J Peripher Nerv Syst 2024; 29:135-160. [PMID: 38600691 DOI: 10.1111/jns.12625] [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: 01/23/2024] [Revised: 03/02/2024] [Accepted: 03/28/2024] [Indexed: 04/12/2024]
Abstract
Nerve conduction studies are usually the first diagnostic step in peripheral nerve disorders and their results are the basis for planning further investigations. However, there are some commonplaces in the interpretation of electrodiagnostic findings in peripheral neuropathies that, although useful in the everyday practice, may be misleading: (1) conduction block and abnormal temporal dispersion are distinctive features of acquired demyelinating disorders; (2) hereditary neuropathies are characterized by uniform slowing of conduction velocity; (3) axonal neuropathies are simply diagnosed by reduced amplitude of motor and sensory nerve action potentials with normal or slightly slow conduction velocity. In this review, we reappraise the occurrence of uniform and non-uniform conduction velocity slowing, conduction block and temporal dispersion in demyelinating, dysmyelinating and axonal neuropathies attempting, with a translational approach, a correlation between electrophysiological and pathological features as derived from sensory nerve biopsy in patients and animal models. Additionally, we provide some hints to navigate in this complex field.
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Affiliation(s)
- Antonino Uncini
- Department of Neurosciences, Imaging and Clinical Sciences, University "G. d'Annunzio", Chieti-Pescara, Italy
| | - Tiziana Cavallaro
- Department of Neurosciences, Biomedicine, and Movement Sciences, University of Verona, Verona, Italy
| | - Gian Maria Fabrizi
- Department of Neurosciences, Biomedicine, and Movement Sciences, University of Verona, Verona, Italy
| | - Fiore Manganelli
- Department of Neurosciences, Reproductive Sciences and Odontostomatology, University of Naples "Federico II", Naples, Italy
| | - Jean-Michel Vallat
- Department of Neurology, National Reference Center for "Rare Peripheral Neuropathies", CHU Dupuytren, Limoges, France
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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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3
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Kagiava A, Karaiskos C, Lapathitis G, Heslegrave A, Sargiannidou I, Zetterberg H, Bosch A, Kleopa KA. Gene replacement therapy in two Golgi-retained CMT1X mutants before and after the onset of demyelinating neuropathy. Mol Ther Methods Clin Dev 2023; 30:377-393. [PMID: 37645436 PMCID: PMC10460951 DOI: 10.1016/j.omtm.2023.07.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Accepted: 07/31/2023] [Indexed: 08/31/2023]
Abstract
X-linked Charcot-Marie-Tooth disease type 1 (CMT1X) is a demyelinating neuropathy resulting from loss-of-function mutations affecting the GJB1/connexin 32 (Cx32) gene. We previously showed functional and morphological improvement in Gjb1-null mice following AAV9-mediated delivery of human Cx32 driven by the myelin protein zero (Mpz) promoter in Schwann cells. However, CMT1X mutants may interfere with virally delivered wild-type (WT) Cx32. To confirm the efficacy of this vector also in the presence of CMT1X mutants, we delivered AAV9-Mpz-GJB1 by lumbar intrathecal injection in R75W/Gjb1-null and N175D/Gjb1-null transgenic lines expressing Golgi-retained mutations, before and after the onset of the neuropathy. Widespread expression of virally delivered Cx32 was demonstrated in both genotypes. Re-establishment of WT Cx32 function resulted in improved muscle strength and increased sciatic nerve motor conduction velocities in all treated groups from both mutant lines when treated before as well as after the onset of the neuropathy. Furthermore, morphological analysis showed improvement of myelination and reduction of inflammation in lumbar motor roots and peripheral nerves. In conclusion, this study provides proof of principle for a clinically translatable gene therapy approach to treat CMT1X before and after the onset of the neuropathy, even in the presence of endogenously expressed Golgi-retained Cx32 mutants.
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Affiliation(s)
- Alexia Kagiava
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, 2371 Nicosia, Cyprus
| | - Christos Karaiskos
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, 2371 Nicosia, Cyprus
| | - George Lapathitis
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, 2371 Nicosia, Cyprus
| | - Amanda Heslegrave
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London WC1E 6BT, UK
- UK Dementia Research Institute at UCL, London WC1E 6BT, UK
| | - Irene Sargiannidou
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, 2371 Nicosia, Cyprus
| | - Henrik Zetterberg
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London WC1E 6BT, UK
- UK Dementia Research Institute at UCL, London WC1E 6BT, UK
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, the Sahlgrenska Academy at the University of Gothenburg, 40530 Mölndal, Sweden
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, 40530 Mölndal, Sweden
- Hong Kong Center for Neurodegenerative Diseases, Clear Water Bay, Hong Kong, China
- Wisconsin Alzheimer’s Disease Research Center, University of Wisconsin School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53792, USA
| | - Assumpció Bosch
- Department of Biochemistry & Molecular Biology, Institute of Neurosciences, Universitat Autònoma de Barcelona, 08193 Bellatera, Spain
- Unitat Mixta UAB-VHIR, Vall d'Hebron Institut de Recerca (VHIR), 08035 Barcelona, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, 028029 Madrid, Spain
| | - Kleopas A. Kleopa
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, 2371 Nicosia, Cyprus
- Center for Neuromuscular Disorders, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, 2371 Nicosia, Cyprus
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Kim HJ, Kim SB, Kim HS, Kwon HM, Park JH, Lee AJ, Lim SO, Nam SH, Hong YB, Chung KW, Choi BO. Phenotypic heterogeneity in patients with NEFL-related Charcot-Marie-Tooth disease. Mol Genet Genomic Med 2022; 10:e1870. [PMID: 35044100 PMCID: PMC8830812 DOI: 10.1002/mgg3.1870] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 09/12/2021] [Accepted: 12/20/2021] [Indexed: 11/28/2022] Open
Abstract
Charcot–Marie–Tooth disease (CMT) is the most common hereditary peripheral neuropathy. Mutations in the neurofilament light polypeptide (NEFL) gene produce diverse clinical phenotypes, including demyelinating (CMT1F), axonal (CMT2E), and intermediate (CMTDIG) neuropathies. From 2005 to 2020, 1,143 Korean CMT families underwent gene sequencing, and we investigated the clinical, genetic, and neuroimaging spectra of NEFL‐related CMT patients. Ten NEFL mutations in 17 families (1.49%) were identified, of which three (p.L312P, p.Y443N, and p.K467N) were novel. Eight de novo cases were identified at a rate of 0.47 based on a cosegregation analysis. The age of onset was ≤3 years in five cases (13.5%). The patients revealed additional features including delayed walking, ataxia, dysphagia, dysarthria, dementia, ptosis, waddling gait, tremor, hearing loss, and abnormal visual evoked potential. Signs of ataxia were found in 26 patients (70.3%). In leg MRI analyses, various degrees of intramuscular fat infiltration were found. All compartments were evenly affected in CMT1F patients. The anterior and anterolateral compartments were affected in CMT2E, and the posterior compartment was affected in CMTDIG. Thus, NEFL‐related CMT patients showed phenotypic heterogeneities. This study's clinical, genetic, and neuroimaging results could be helpful in the evaluation of novel NEFL variants and differential diagnosis against other CMT subtypes.
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Affiliation(s)
- Hye Jin Kim
- Department of Health Sciences and Technology, SAIHST, Sungkyunkwan University, Seoul, Korea.,Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Sang Beom Kim
- Department of Neurology, Kyung Hee University Hospital at Gangdong, Kyung Hee University School of Medicine, Seoul, Republic of Korea
| | - Hyun Su Kim
- Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Hye Mi Kwon
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Jae Hong Park
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Ah Jin Lee
- Department of Biological Sciences, Kongju National University, Gongju, Korea
| | - Si On Lim
- Department of Biological Sciences, Kongju National University, Gongju, Korea
| | - Soo Hyun Nam
- Stem Cell & Regenerative Medicine Institute, Samsung Medical Center, Seoul, Korea
| | - Young Bin Hong
- Department of Biochemistry, College of Medicine, Dong-A University, Busan, Korea
| | - Ki Wha Chung
- Department of Biological Sciences, Kongju National University, Gongju, Korea
| | - Byung-Ok Choi
- Department of Health Sciences and Technology, SAIHST, Sungkyunkwan University, Seoul, Korea.,Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.,Stem Cell & Regenerative Medicine Institute, Samsung Medical Center, Seoul, Korea
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5
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Hwang S, Park CH, Kim REY, Kim HJ, Choi YS, Kim SA, Yoo JH, Chung KW, Choi BO, Lee HW. Cerebellar White Matter Abnormalities in Charcot-Marie-Tooth Disease: A Combined Volumetry and Diffusion Tensor Imaging Analysis. J Clin Med 2021; 10:jcm10214945. [PMID: 34768465 PMCID: PMC8584387 DOI: 10.3390/jcm10214945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Revised: 10/19/2021] [Accepted: 10/21/2021] [Indexed: 11/20/2022] Open
Abstract
Charcot–Marie–Tooth disease (CMT) is a genetically heterogeneous hereditary peripheral neuropathy. Brain volumetry and diffusion tensor imaging (DTI) were performed in 47 controls and 47 CMT patients with PMP22 duplication (n = 10), MFN2 (n = 15), GJB1 (n = 11), or NEFL mutations (n = 11) to investigate for structural changes in the cerebellum. Volume of cerebellar white matter (WM) was significantly reduced in CMT patients with NEFL mutations. Abnormal DTI findings were observed in the superior, middle, and inferior cerebellar peduncles, predominantly in NEFL mutations and partly in GJB1 mutations. Cerebellar ataxia was more prevalent in the NEFL mutation group (72.7%) than the GJB1 mutation group (9.1%) but was not observed in other genotypic subtypes, which indicates that structural cerebellar abnormalities were associated with the presence of cerebellar ataxia. However, NEFL and GJB1 mutations did not affect cerebellar gray matter (GM), and neither cerebellar GM nor WM abnormalities were observed in the PMP22 duplication or MFN2 mutation groups. We found structural evidence of cerebellar WM abnormalities in CMT patients with NEFL and GJB1 mutations and an association between cerebellar WM involvement and cerebellar ataxia in these genetic subtypes, especially in the NEFL subgroup. Therefore, we suggest that neuroimaging, such as MRI volumetry or DTI, for CMT patients could play an important role in detecting abnormalities of cerebellar WM.
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Affiliation(s)
- Sungeun Hwang
- Departments of Neurology, Ewha Womans University Mokdong Hospital, Seoul 07985, Korea;
| | - Chang-Hyun Park
- Departments of Neurology, Ewha Womans University School of Medicine and Ewha Medical Research Institute, Seoul 07985, Korea; (C.-H.P.); (H.J.K.)
| | - Regina Eun-Young Kim
- Institute for Human Genomic Study, College of Medicine, Korea University, Ansan 15355, Korea;
- Department of Psychiatry, University of Iowa, Iowa City, IA 52242, USA
| | - Hyeon Jin Kim
- Departments of Neurology, Ewha Womans University School of Medicine and Ewha Medical Research Institute, Seoul 07985, Korea; (C.-H.P.); (H.J.K.)
- Department of Neurology, Korea University Ansan Hospital, Ansan 15355, Korea
| | - Yun Seo Choi
- Departments of Medical Science, Ewha Womans University School of Medicine and Ewha Medical Research Institute, Seoul 07804, Korea; (Y.S.C.); (S.-A.K.)
| | - Sol-Ah Kim
- Departments of Medical Science, Ewha Womans University School of Medicine and Ewha Medical Research Institute, Seoul 07804, Korea; (Y.S.C.); (S.-A.K.)
| | - Jeong Hyun Yoo
- Department of Radiology, College of Medicine, Ewha Womans University, Seoul 07985, Korea;
| | - Ki Wha Chung
- Department of Biological Sciences, Kongju National University, Kongju 32588, Korea;
| | - Byung-Ok Choi
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, Korea
- Department of Health Sciences and Technology, Samsung Advanced Institute for Health Sciences & Technology, Sungkyunkwan University, Seoul 06351, Korea
- Stem Cell & Regenerative Medicine Institute, Samsung Medical Center, Seoul 06351, Korea
- Correspondence: (B.-O.C.); (H.W.L.); Tel.: +82-2-3410-1296 (B.-O.C.); +82-2-2650-2673 (H.W.L.); Fax: +82-2-3410-0052 (B.-O.C.); +82-2-2650-5958 (H.W.L.)
| | - Hyang Woon Lee
- Departments of Neurology, Ewha Womans University Mokdong Hospital, Seoul 07985, Korea;
- Departments of Neurology, Ewha Womans University School of Medicine and Ewha Medical Research Institute, Seoul 07985, Korea; (C.-H.P.); (H.J.K.)
- Departments of Medical Science, Ewha Womans University School of Medicine and Ewha Medical Research Institute, Seoul 07804, Korea; (Y.S.C.); (S.-A.K.)
- Department of Computational Medicine, Ewha Womans University, Seoul 07985, Korea
- Department of System Health Science & Engineering, Ewha Womans University, Seoul 03765, Korea
- Correspondence: (B.-O.C.); (H.W.L.); Tel.: +82-2-3410-1296 (B.-O.C.); +82-2-2650-2673 (H.W.L.); Fax: +82-2-3410-0052 (B.-O.C.); +82-2-2650-5958 (H.W.L.)
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6
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Kanwal S, Choi YJI, Lim SO, Choi HJ, Park JH, Nuzhat R, Khan A, Perveen S, Choi BO, Chung KW. Novel homozygous mutations in Pakistani families with Charcot-Marie-Tooth disease. BMC Med Genomics 2021; 14:174. [PMID: 34193129 PMCID: PMC8247155 DOI: 10.1186/s12920-021-01019-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 06/18/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Charcot-Marie-Tooth disease (CMT) is a group of genetically and clinically heterogeneous peripheral nervous system disorders. Few studies have identified genetic causes of CMT in the Pakistani patients. METHODS This study was performed to identify pathogenic mutations in five consanguineous Pakistani CMT families negative for PMP22 duplication. Genomic screening was performed by application of whole exome sequencing. RESULTS We identified five pathogenic or likely pathogenic homozygous mutations in four genes: c.2599C > T (p.Gln867*) and c.3650G > A (p.Gly1217Asp) in SH3TC2, c.19C > T (p.Arg7*) in HK1, c.247delG (p.Gly83Alafs*44) in REEP1, and c.334G > A (p.Val112Met) in MFN2. These mutations have not been reported in CMT patients. Mutations in SH3TC2, HK1, REEP1, and MFN2 have been reported to be associated with CMT4C, CMT4G, dHMN5B (DSMA5B), and CMT2A, respectively. The genotype-phenotype correlations were confirmed in all the examined families. We also confirmed that both alleles from the homozygous variants originated from a single ancestor using homozygosity mapping. CONCLUSIONS This study found five novel mutations as the underlying causes of CMT. Pathogenic mutations in SH3TC2, HK1, and REEP1 have been reported rarely in other populations, suggesting ethnic-specific distribution. This study would be useful for the exact molecular diagnosis and treatment of CMT in Pakistani patients.
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Affiliation(s)
- Sumaira Kanwal
- Department of Biosciences, COMSATS University Islamabad, Sahiwal, Pakistan
| | - Yu JIn Choi
- Department of Biological Sciences, Kongju National University, 56 Gongjudaehakro, Gongju, 32588, Korea
| | - Si On Lim
- Department of Biological Sciences, Kongju National University, 56 Gongjudaehakro, Gongju, 32588, Korea
| | - Hee Ji Choi
- Department of Biological Sciences, Kongju National University, 56 Gongjudaehakro, Gongju, 32588, Korea
| | - Jin Hee Park
- Department of Biological Sciences, Kongju National University, 56 Gongjudaehakro, Gongju, 32588, Korea
| | - Rana Nuzhat
- Department of Pediatric Neurology, The Children Hospital and Institute of Child Health, Multan, Pakistan
| | - Aneela Khan
- Department of Pediatric Neurology, The Children Hospital and Institute of Child Health, Multan, Pakistan
| | - Shazia Perveen
- Department of Zoology, The Women University, Multan, Pakistan
| | - Byung-Ok Choi
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon-ro, Gangnam-gu, Seoul, 06351, Korea.
| | - Ki Wha Chung
- Department of Biological Sciences, Kongju National University, 56 Gongjudaehakro, Gongju, 32588, Korea.
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7
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Peinado A, Asche-Godin SL, Freidin MM, Abrams CK. Effects of early crush on aging wild type and Connexin 32 knockout mice: Evidence for a neuroprotective state in CMT1X mouse nerve. J Peripher Nerv Syst 2021; 26:167-176. [PMID: 33624350 DOI: 10.1111/jns.12436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 01/19/2021] [Accepted: 02/18/2021] [Indexed: 11/29/2022]
Abstract
The long-term sequelae of nerve injury as well as age-related neurodegeneration have been documented in numerous studies, however the role of Cx32 in these processes is not well understood. There is a need for better understanding of the molecular mechanisms that underlie long-term suboptimal nerve function and for approaches to prevent or improve it. In this communication we describe our studies using whole animal electrophysiology to examine the long-term sequelae of sciatic nerve crush in both WT and Cx32KO mice, a model of X-linked Charcot Marie Tooth disease, a subtype of inherited peripheral neuropathies. We present results from electrical nerve recordings done 14 to 27 days and 18 to 20 months after a unilateral sciatic nerve crush performed on 35 to 37-day old mice. Contrary to expectations, we find that whereas crush injury leads to a degradation of WT nerve function relative to uninjured nerves at 18 to 20 months, previously crushed Cx32KO nerves perform at the same level as their uninjured counterparts. Thus, 18 to 20 months after injury, WT nerves perform below the level of normal (uninjured) WT nerves in both motor and sensory nerve function. In contrast, measures of nerve function in Cx32KO mice are degraded for sensory axons but exhibit no additional dysfunction in motor axons. Early nerve injury has no negative electrophysiologic effect on the Cx32 KO motor nerves. Based on our prior demonstration that the transcriptomic profile of uninjured Cx32KO and injured WT sciatic nerves are very similar, the lack of an additional effect of crush on Cx32KO motor nerve parameters suggests that Cx32 knockout may implement a form of neuroprotection that limits the effects of subsequent injury.
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Affiliation(s)
- Alejandro Peinado
- Department of Neurology and Rehabilitation, College of Medicine, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Samantha L Asche-Godin
- National Center for the Medical Consequences of Spinal Cord Injury, James J. Peters VA Medical Center, Bronx, NY and The Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Mona M Freidin
- Department of Neurology and Rehabilitation, College of Medicine, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Charles K Abrams
- Department of Neurology and Rehabilitation, College of Medicine, University of Illinois at Chicago, Chicago, Illinois, USA
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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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Kim HS, Kim HJ, Nam SH, Kim SB, Choi YJ, Lee KS, Chung KW, Yoon YC, Choi BO. Clinical and Neuroimaging Features in Charcot-Marie-Tooth Patients with GDAP1 Mutations. J Clin Neurol 2021; 17:52-62. [PMID: 33480199 PMCID: PMC7840330 DOI: 10.3988/jcn.2021.17.1.52] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 09/15/2020] [Accepted: 09/15/2020] [Indexed: 01/04/2023] Open
Abstract
Background and Purpose Mutations in the ganglioside-induced differentiation-associated protein 1 gene (GDAP1) are known to cause Charcot-Marie-Tooth disease (CMT). These mutations are very rare in most countries, but not in certain Mediterranean countries. The purpose of this study was to identify the clinical and neuroimaging characteristics of Korean CMT patients with GDAP1 mutations. Methods Gene sequencing was applied to 1,143 families in whom CMT had been diagnosed from 2005 to 2020. PMP22 duplication was found in 344 families, and whole-exome sequencing was performed in 699 patients. Magnetic resonance imaging (MRI) were obtained using either a 1.5-T or 3.0-T MRI system. Results We found ten patients from eight families with GDAP1 mutations: five with autosomal dominant (AD) CMT type 2K (three families with p.R120W and two families with p.Q218E) and three with autosomal recessive (AR) intermediate CMT type A (two families with homozygous p.H256R and one family with p.P111H and p.V219G mutations). The frequency was about 1.0% exclusive of the PMP22 duplication, which is similar to that in other Asian countries. There were clinical differences among AD GDAP1 patients according to mutation sites. Surprisingly, fat infiltrations evident in lower-limb MRI differed between AD and AR patients. The posterior-compartment muscles in the calf were affected early and predominantly in AD patients, whereas AR patients showed fat infiltration predominantly in the anterolateral-compartment muscles. Conclusions This is the first cohort report on Korean patients with GDAP1 mutations. The patients with AD and AR inheritance routes exhibited different clinical and neuroimaging features in the lower extremities. We believe that these results will help to expand the knowledge of the clinical, genetic, and neuroimaging features of CMT.
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Affiliation(s)
- Hyun Su Kim
- Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Hye Jin Kim
- Department of Health Sciences and Technology, SAIHST, Sungkyunkwan University, Seoul, Korea.,Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Soo Hyun Nam
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Sang Beom Kim
- Department of Neurology, Kyung Hee University Hospital at Gangdong, Kyung Hee University School of Medicine, Seoul, Korea
| | - Yu Jin Choi
- Department of Biological Sciences, Kongju National University, Gongju, Korea
| | - Kyung Suk Lee
- Department of Physics Education, Kongju National University, Gongju, Korea
| | - Ki Wha Chung
- Department of Biological Sciences, Kongju National University, Gongju, Korea
| | - Young Cheol Yoon
- Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
| | - Byung Ok Choi
- Department of Health Sciences and Technology, SAIHST, Sungkyunkwan University, Seoul, Korea.,Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.,Stem Cell & Regenerative Medicine Institute, Samsung Medical Center, Seoul, Korea.
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AAV9-mediated Schwann cell-targeted gene therapy rescues a model of demyelinating neuropathy. Gene Ther 2021; 28:659-675. [PMID: 33692503 PMCID: PMC8599011 DOI: 10.1038/s41434-021-00250-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 02/15/2021] [Accepted: 02/19/2021] [Indexed: 01/31/2023]
Abstract
Mutations in the GJB1 gene, encoding the gap junction (GJ) protein connexin32 (Cx32), cause X-linked Charcot-Marie-Tooth disease (CMT1X), an inherited demyelinating neuropathy. We developed a gene therapy approach for CMT1X using an AAV9 vector to deliver the GJB1/Cx32 gene under the myelin protein zero (Mpz) promoter for targeted expression in Schwann cells. Lumbar intrathecal injection of the AAV9-Mpz.GJB1 resulted in widespread biodistribution in the peripheral nervous system including lumbar roots, sciatic and femoral nerves, as well as in Cx32 expression in the paranodal non-compact myelin areas of myelinated fibers. A pre-, as well as post-onset treatment trial in Gjb1-null mice, demonstrated improved motor performance and sciatic nerve conduction velocities along with improved myelination and reduced inflammation in peripheral nerve tissues. Blood biomarker levels were also significantly ameliorated in treated mice. This study provides evidence that a clinically translatable AAV9-mediated gene therapy approach targeting Schwann cells could potentially treat CMT1X.
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11
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Genetic mechanisms of peripheral nerve disease. Neurosci Lett 2020; 742:135357. [PMID: 33249104 DOI: 10.1016/j.neulet.2020.135357] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 08/24/2020] [Accepted: 09/02/2020] [Indexed: 12/17/2022]
Abstract
Peripheral neuropathies of genetic etiology are a very diverse group of disorders manifesting either as non-syndromic inherited neuropathies without significant manifestations outside the peripheral nervous system, or as part of a systemic or syndromic genetic disorder. The former and most frequent group is collectively known as Charcot-Marie-Tooth disease (CMT), with prevalence as high as 1:2,500 world-wide, and has proven to be genetically highly heterogeneous. More than 100 different genes have been identified so far to cause various CMT forms, following all possible inheritance patterns. CMT causative genes belong to several common functional pathways that are essential for the integrity of the peripheral nerve. Their discovery has provided insights into the normal biology of axons and myelinating cells, and has highlighted the molecular mechanisms including both loss of function and gain of function effects, leading to peripheral nerve degeneration. Demyelinating neuropathies result from dysfunction of genes primarily affecting myelinating Schwann cells, while axonal neuropathies are caused by genes affecting mostly neurons and their long axons. Furthermore, mutation in genes expressed outside the nervous system, as in the case of inherited amyloid neuropathies, may cause peripheral neuropathy resulting from accumulation of β-structured amyloid fibrils in peripheral nerves in addition to various organs. Increasing insights into the molecular-genetic mechanisms have revealed potential therapeutic targets. These will enable the development of novel therapeutics for genetic neuropathies that remain, in their majority, without effective treatment.
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12
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Sargiannidou I, Kagiava A, Kleopa KA. Gene therapy approaches targeting Schwann cells for demyelinating neuropathies. Brain Res 2020; 1728:146572. [PMID: 31790684 DOI: 10.1016/j.brainres.2019.146572] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 11/12/2019] [Accepted: 11/26/2019] [Indexed: 11/27/2022]
Abstract
Charcot-Marie-Tooth disease (CMT) encompasses numerous genetically heterogeneous inherited neuropathies, which together are one of the commonest neurogenetic disorders. Axonal CMT types result from mutations in neuronally expressed genes, whereas demyelinating CMT forms mostly result from mutations in genes expressed by myelinating Schwann cells. The demyelinating forms are the most common, and may be caused by dominant mutations and gene dosage effects (as in CMT1), as well as by recessive mutations and loss of function mechanisms (as in CMT4). The discovery of causative genes and increasing insights into molecular mechanisms through the study of experimental disease models has provided the basis for the development of gene therapy approaches. For demyelinating CMT, gene silencing or gene replacement strategies need to be targeted to Schwann cells. Progress in gene replacement for two different CMT forms, including CMT1X caused by GJB1 gene mutations, and CMT4C, caused by SH3TC2 gene mutations, has been made through the use of a myelin-specific promoter to restrict expression in Schwann cells, and by lumbar intrathecal delivery of lentiviral viral vectors to achieve more widespread biodistribution in the peripheral nervous system. This review summarizes the molecular-genetic mechanisms of selected demyelinating CMT neuropathies and the progress made so far, as well as the remaining challenges in the path towards a gene therapy to treat these disorders through the use of optimal gene therapy tools including clinically translatable delivery methods and adeno-associated viral (AAV) vectors.
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Affiliation(s)
- Irene Sargiannidou
- Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - Alexia Kagiava
- Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - Kleopas A Kleopa
- Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus; Neurology Clinics, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus.
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13
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Kagiava A, Richter J, Tryfonos C, Karaiskos C, Heslegrave AJ, Sargiannidou I, Rossor AM, Zetterberg H, Reilly MM, Christodoulou C, Kleopa KA. Gene replacement therapy after neuropathy onset provides therapeutic benefit in a model of CMT1X. Hum Mol Genet 2019; 28:3528-3542. [PMID: 31411673 DOI: 10.1093/hmg/ddz199] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 07/26/2019] [Accepted: 07/31/2019] [Indexed: 12/22/2022] Open
Abstract
X-linked Charcot-Marie-Tooth disease (CMT1X), one of the commonest forms of inherited demyelinating neuropathy, results from GJB1 gene mutations causing loss of function of the gap junction protein connexin32 (Cx32). The aim of this study was to examine whether delayed gene replacement therapy after the onset of peripheral neuropathy can provide a therapeutic benefit in the Gjb1-null/Cx32 knockout model of CMT1X. After delivery of the LV-Mpz.GJB1 lentiviral vector by a single lumbar intrathecal injection into 6-month-old Gjb1-null mice, we confirmed expression of Cx32 in lumbar roots and sciatic nerves correctly localized at the paranodal myelin areas. Gjb1-null mice treated with LV-Mpz.GJB1 compared with LV-Mpz.Egfp (mock) vector at the age of 6 months showed improved motor performance at 8 and 10 months. Furthermore, treated mice showed increased sciatic nerve conduction velocities, improvement of myelination and reduced inflammation in lumbar roots and peripheral nerves at 10 months of age, along with enhanced quadriceps muscle innervation. Plasma neurofilament light (NEFL) levels, a clinically relevant biomarker, were also ameliorated in fully treated mice. Intrathecal gene delivery after the onset of peripheral neuropathy offers a significant therapeutic benefit in this disease model, providing a proof of principle for treating patients with CMT1X at different ages.
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Affiliation(s)
- A Kagiava
- Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - J Richter
- Department of Molecular Virology, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - C Tryfonos
- Department of Molecular Virology, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - C Karaiskos
- Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - A J Heslegrave
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, United Kingdom
| | - I Sargiannidou
- Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - A M Rossor
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, United Kingdom
| | - H Zetterberg
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London, United Kingdom
- UK Dementia Research Institute at UCL, London, United Kingdom
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, the Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
| | - M M Reilly
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, United Kingdom
| | - C Christodoulou
- Department of Molecular Virology, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - K A Kleopa
- Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
- Neurology Clinics, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
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Charcot-Marie-Tooth: From Molecules to Therapy. Int J Mol Sci 2019; 20:ijms20143419. [PMID: 31336816 PMCID: PMC6679156 DOI: 10.3390/ijms20143419] [Citation(s) in RCA: 96] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 07/03/2019] [Accepted: 07/03/2019] [Indexed: 01/08/2023] Open
Abstract
Charcot-Marie-Tooth (CMT) is the most prevalent category of inherited neuropathy. The most common inheritance pattern is autosomal dominant, though there also are X-linked and autosomal recessive subtypes. In addition to a variety of inheritance patterns, there are a myriad of genes associated with CMT, reflecting the heterogeneity of this disorder. Next generation sequencing (NGS) has expanded and simplified the diagnostic yield of genes/molecules underlying and/or associated with CMT, which is of paramount importance in providing a substrate for current and future targeted disease-modifying treatment options. Considerable research attention for disease-modifying therapy has been geared towards the most commonly encountered genetic mutations (PMP22, GJB1, MPZ, and MFN2). In this review, we highlight the clinical background, molecular understanding, and therapeutic investigations of these CMT subtypes, while also discussing therapeutic research pertinent to the remaining less common CMT subtypes.
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15
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Gouvea SP, Tomaselli PJ, Barretto LS, Perina KCB, Nyshyama FS, Nicolau N, Lourenço CM, Marques W. New novel mutations in Brazilian families with X-linked Charcot-Marie-Tooth disease. J Peripher Nerv Syst 2019; 24:207-212. [PMID: 31119804 DOI: 10.1111/jns.12327] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 05/20/2019] [Accepted: 05/20/2019] [Indexed: 11/29/2022]
Abstract
Mutations in the GJB1 gene are the second most frequent cause of Charcot-Marie-Tooth disease (CMT), accounting for approximately 10% of CMT cases worldwide. We retrospectively analyzed detailed clinical and neurophysiological data on four Brazilian families carrying novel mutations of the GJB1 gene. Mutations were identified by bidirectional Sanger sequence analysis on the GJB1 coding region. We identified a total of 12 subjects from four different kindred. There was no male-to-male transmission, and their clinical pictures were within the expected spectrum for GJB1-related neuropathy. Males were more severely affected than females. Five out of the eight females only had subclinical neuropathy. Nerve conduction velocities were in the intermediate range in the male patients and higher in the females affected. These mutations increase the genotypic variability associated with GJB1.
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Affiliation(s)
- Silmara P Gouvea
- Neurogenetics, Department of Neurosciences and Behavioral Sciences, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Pedro J Tomaselli
- Neuromuscular Section, University Hospital of Ribeirão Preto, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Luiza S Barretto
- Neuromuscular Section, University Hospital of Ribeirão Preto, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Keity C B Perina
- Neurogenetics, Department of Neurosciences and Behavioral Sciences, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Fulviana S Nyshyama
- Neurogenetics, Department of Neurosciences and Behavioral Sciences, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Nilson Nicolau
- Institute of Genetics and Biochemistry, Federal University of Uberlândia, Uberlândia, Brazil
| | - Charles M Lourenço
- Neurogenetics, Department of Neurosciences and Behavioral Sciences, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
- Neuromuscular Section, University Hospital of Ribeirão Preto, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Wilson Marques
- Neurogenetics, Department of Neurosciences and Behavioral Sciences, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
- Neuromuscular Section, University Hospital of Ribeirão Preto, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
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16
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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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17
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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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18
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Draper ACE, Piercy RJ. Pathological classification of equine recurrent laryngeal neuropathy. J Vet Intern Med 2018; 32:1397-1409. [PMID: 29691904 PMCID: PMC6060325 DOI: 10.1111/jvim.15142] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 03/12/2018] [Accepted: 03/29/2018] [Indexed: 12/28/2022] Open
Abstract
Recurrent Laryngeal Neuropathy (RLN) is a highly prevalent and predominantly left-sided, degenerative disorder of the recurrent laryngeal nerves (RLn) of tall horses, that causes inspiratory stridor at exercise because of intrinsic laryngeal muscle paresis. The associated laryngeal dysfunction and exercise intolerance in athletic horses commonly leads to surgical intervention, retirement or euthanasia with associated financial and welfare implications. Despite speculation, there is a lack of consensus and conflicting evidence supporting the primary classification of RLN, as either a distal ("dying back") axonopathy or as a primary myelinopathy and as either a (bilateral) mononeuropathy or a polyneuropathy; this uncertainty hinders etiological and pathophysiological research. In this review, we discuss the neuropathological changes and electrophysiological deficits reported in the RLn of affected horses, and the evidence for correct classification of the disorder. In so doing, we summarize and reveal the limitations of much historical research on RLN and propose future directions that might best help identify the etiology and pathophysiology of this enigmatic disorder.
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Affiliation(s)
- Alexandra C. E. Draper
- Comparative Neuromuscular Disease LaboratoryDepartment is Clinical Science and Services, Royal Veterinary CollegeLondonUnited Kingdom
| | - Richard J. Piercy
- Comparative Neuromuscular Disease LaboratoryDepartment is Clinical Science and Services, Royal Veterinary CollegeLondonUnited Kingdom
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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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20
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Lee M, Park CH, Chung HK, Kim HJ, Choi Y, Yoo JH, Yoon YC, Hong YB, Chung KW, Choi BO, Lee HW. Cerebral white matter abnormalities in patients with charcot-marie-tooth disease. Ann Neurol 2017; 81:147-151. [PMID: 27863451 DOI: 10.1002/ana.24824] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 11/09/2016] [Accepted: 11/09/2016] [Indexed: 11/08/2022]
Abstract
Here, we report the structural evidence of cerebral white matter abnormalities in Charcot-Marie-Tooth (CMT) patients and the relationship between these abnormalities and clinical disability. Brain diffusion tensor imaging (DTI) was performed in CMT patients with demyelinating (CMT1A/CMT1E), axonal (CMT2A/CMT2E), or intermediate (CMTX1/DI-CMT) peripheral neuropathy. Although all patients had normal brain magnetic resonance imaging, all genetic subgroups except CMT1A had abnormal DTI findings indicative of significant cerebral white matter abnormalities: decreased fractional anisotropy and axial diffusivity, and increased radial diffusivity. DTI abnormalities were correlated with clinical disability, suggesting that there is comorbidity of central nervous system damage with peripheral neuropathy in CMT patients. ANN NEUROL 2017;81:147-151.
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Affiliation(s)
- Mina Lee
- Department of Neurology, Ewha Womans University School of Medicine and Ewha Medical Research Institute, Seoul, South Korea.,Department of Medical Science, Ewha Womans University School of Medicine and Ewha Medical Research Institute, Seoul, South Korea
| | - Chang-Hyun Park
- Department of Neurology, Ewha Womans University School of Medicine and Ewha Medical Research Institute, Seoul, South Korea.,Department of Medical Science, Ewha Womans University School of Medicine and Ewha Medical Research Institute, Seoul, South Korea
| | - Hwa-Kyung Chung
- Department of Neurology, Ewha Womans University School of Medicine and Ewha Medical Research Institute, Seoul, South Korea
| | - Hyeon Jin Kim
- Department of Neurology, Ewha Womans University School of Medicine and Ewha Medical Research Institute, Seoul, South Korea
| | - Yunseo Choi
- Department of Neurology, Ewha Womans University School of Medicine and Ewha Medical Research Institute, Seoul, South Korea.,Department of Medical Science, Ewha Womans University School of Medicine and Ewha Medical Research Institute, Seoul, South Korea
| | - Jeong Hyun Yoo
- Department of Radiology, Ewha Womans University School of Medicine and Ewha Medical Research Institute, Seoul, South Korea
| | - Young Chul Yoon
- Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea
| | - Young Bin Hong
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea
| | - Ki Wha Chung
- Department of Biological Science, Kongju National University, Gongju, South Korea
| | - Byung-Ok Choi
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.,Neuroscience Center, Samsung Medical Center, Seoul, South Korea
| | - Hyang Woon Lee
- Department of Neurology, Ewha Womans University School of Medicine and Ewha Medical Research Institute, Seoul, South Korea.,Department of Medical Science, Ewha Womans University School of Medicine and Ewha Medical Research Institute, Seoul, South Korea
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21
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Tomaselli PJ, Rossor AM, Horga A, Jaunmuktane Z, Carr A, Saveri P, Piscosquito G, Pareyson D, Laura M, Blake JC, Poh R, Polke J, Houlden H, Reilly MM. Mutations in noncoding regions of GJB1 are a major cause of X-linked CMT. Neurology 2017; 88:1445-1453. [PMID: 28283593 PMCID: PMC5386440 DOI: 10.1212/wnl.0000000000003819] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2016] [Accepted: 01/18/2017] [Indexed: 01/03/2023] Open
Abstract
OBJECTIVE To determine the prevalence and clinical and genetic characteristics of patients with X-linked Charcot-Marie-Tooth disease (CMT) due to mutations in noncoding regions of the gap junction β-1 gene (GJB1). METHODS Mutations were identified by bidirectional Sanger sequence analysis of the 595 bases of the upstream promoter region, and 25 bases of the 3' untranslated region (UTR) sequence in patients in whom mutations in the coding region had been excluded. Clinical and neurophysiologic data were retrospectively collected. RESULTS Five mutations were detected in 25 individuals from 10 kindreds representing 11.4% of all cases of CMTX1 diagnosed in our neurogenetics laboratory between 1996 and 2016. Four pathogenic mutations, c.-17G>A, c.-17+1G>T, c.-103C>T, and c.-146-90_146-89insT were detected in the 5'UTR. A novel mutation, c.*15C>T, was detected in the 3' UTR of GJB1 in 2 unrelated families with CMTX1 and is the first pathogenic mutation in the 3'UTR of any myelin-associated CMT gene. Mutations segregated with the phenotype, were at sites predicted to be pathogenic, and were not present in the normal population. CONCLUSIONS Mutations in noncoding DNA are a major cause of CMTX1 and highlight the importance of mutations in noncoding DNA in human disease. Next-generation sequencing platforms for use in inherited neuropathy should therefore include coverage of these regions.
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Affiliation(s)
- Pedro J Tomaselli
- From the MRC Centre for Neuromuscular Diseases (P.J.T., A.M.R., A.H., A.C., M.L., M.M.R.), Department of Neuropathology (Z.J.), and Department of Neurogenetics (R.P., J.P., H.H.), National Hospital for Neurology and Neurosurgery, UCL Institute of Neurology, Queen Square, London, UK; Clinic of Central and Peripheral Degenerative Neuropathies Unit (P.S., G.P., D.P.), Department of Clinical Neurosciences, IRCCS Foundation, C. Besta Neurological Institute, Milan, Italy; Department of Clinical Neurophysiology (J.C.B.), Norfolk and Norwich University Hospital, Norfolk, UK
| | - Alexander M Rossor
- From the MRC Centre for Neuromuscular Diseases (P.J.T., A.M.R., A.H., A.C., M.L., M.M.R.), Department of Neuropathology (Z.J.), and Department of Neurogenetics (R.P., J.P., H.H.), National Hospital for Neurology and Neurosurgery, UCL Institute of Neurology, Queen Square, London, UK; Clinic of Central and Peripheral Degenerative Neuropathies Unit (P.S., G.P., D.P.), Department of Clinical Neurosciences, IRCCS Foundation, C. Besta Neurological Institute, Milan, Italy; Department of Clinical Neurophysiology (J.C.B.), Norfolk and Norwich University Hospital, Norfolk, UK
| | - Alejandro Horga
- From the MRC Centre for Neuromuscular Diseases (P.J.T., A.M.R., A.H., A.C., M.L., M.M.R.), Department of Neuropathology (Z.J.), and Department of Neurogenetics (R.P., J.P., H.H.), National Hospital for Neurology and Neurosurgery, UCL Institute of Neurology, Queen Square, London, UK; Clinic of Central and Peripheral Degenerative Neuropathies Unit (P.S., G.P., D.P.), Department of Clinical Neurosciences, IRCCS Foundation, C. Besta Neurological Institute, Milan, Italy; Department of Clinical Neurophysiology (J.C.B.), Norfolk and Norwich University Hospital, Norfolk, UK
| | - Zane Jaunmuktane
- From the MRC Centre for Neuromuscular Diseases (P.J.T., A.M.R., A.H., A.C., M.L., M.M.R.), Department of Neuropathology (Z.J.), and Department of Neurogenetics (R.P., J.P., H.H.), National Hospital for Neurology and Neurosurgery, UCL Institute of Neurology, Queen Square, London, UK; Clinic of Central and Peripheral Degenerative Neuropathies Unit (P.S., G.P., D.P.), Department of Clinical Neurosciences, IRCCS Foundation, C. Besta Neurological Institute, Milan, Italy; Department of Clinical Neurophysiology (J.C.B.), Norfolk and Norwich University Hospital, Norfolk, UK
| | - Aisling Carr
- From the MRC Centre for Neuromuscular Diseases (P.J.T., A.M.R., A.H., A.C., M.L., M.M.R.), Department of Neuropathology (Z.J.), and Department of Neurogenetics (R.P., J.P., H.H.), National Hospital for Neurology and Neurosurgery, UCL Institute of Neurology, Queen Square, London, UK; Clinic of Central and Peripheral Degenerative Neuropathies Unit (P.S., G.P., D.P.), Department of Clinical Neurosciences, IRCCS Foundation, C. Besta Neurological Institute, Milan, Italy; Department of Clinical Neurophysiology (J.C.B.), Norfolk and Norwich University Hospital, Norfolk, UK
| | - Paola Saveri
- From the MRC Centre for Neuromuscular Diseases (P.J.T., A.M.R., A.H., A.C., M.L., M.M.R.), Department of Neuropathology (Z.J.), and Department of Neurogenetics (R.P., J.P., H.H.), National Hospital for Neurology and Neurosurgery, UCL Institute of Neurology, Queen Square, London, UK; Clinic of Central and Peripheral Degenerative Neuropathies Unit (P.S., G.P., D.P.), Department of Clinical Neurosciences, IRCCS Foundation, C. Besta Neurological Institute, Milan, Italy; Department of Clinical Neurophysiology (J.C.B.), Norfolk and Norwich University Hospital, Norfolk, UK
| | - Giuseppe Piscosquito
- From the MRC Centre for Neuromuscular Diseases (P.J.T., A.M.R., A.H., A.C., M.L., M.M.R.), Department of Neuropathology (Z.J.), and Department of Neurogenetics (R.P., J.P., H.H.), National Hospital for Neurology and Neurosurgery, UCL Institute of Neurology, Queen Square, London, UK; Clinic of Central and Peripheral Degenerative Neuropathies Unit (P.S., G.P., D.P.), Department of Clinical Neurosciences, IRCCS Foundation, C. Besta Neurological Institute, Milan, Italy; Department of Clinical Neurophysiology (J.C.B.), Norfolk and Norwich University Hospital, Norfolk, UK
| | - Davide Pareyson
- From the MRC Centre for Neuromuscular Diseases (P.J.T., A.M.R., A.H., A.C., M.L., M.M.R.), Department of Neuropathology (Z.J.), and Department of Neurogenetics (R.P., J.P., H.H.), National Hospital for Neurology and Neurosurgery, UCL Institute of Neurology, Queen Square, London, UK; Clinic of Central and Peripheral Degenerative Neuropathies Unit (P.S., G.P., D.P.), Department of Clinical Neurosciences, IRCCS Foundation, C. Besta Neurological Institute, Milan, Italy; Department of Clinical Neurophysiology (J.C.B.), Norfolk and Norwich University Hospital, Norfolk, UK
| | - Matilde Laura
- From the MRC Centre for Neuromuscular Diseases (P.J.T., A.M.R., A.H., A.C., M.L., M.M.R.), Department of Neuropathology (Z.J.), and Department of Neurogenetics (R.P., J.P., H.H.), National Hospital for Neurology and Neurosurgery, UCL Institute of Neurology, Queen Square, London, UK; Clinic of Central and Peripheral Degenerative Neuropathies Unit (P.S., G.P., D.P.), Department of Clinical Neurosciences, IRCCS Foundation, C. Besta Neurological Institute, Milan, Italy; Department of Clinical Neurophysiology (J.C.B.), Norfolk and Norwich University Hospital, Norfolk, UK
| | - Julian C Blake
- From the MRC Centre for Neuromuscular Diseases (P.J.T., A.M.R., A.H., A.C., M.L., M.M.R.), Department of Neuropathology (Z.J.), and Department of Neurogenetics (R.P., J.P., H.H.), National Hospital for Neurology and Neurosurgery, UCL Institute of Neurology, Queen Square, London, UK; Clinic of Central and Peripheral Degenerative Neuropathies Unit (P.S., G.P., D.P.), Department of Clinical Neurosciences, IRCCS Foundation, C. Besta Neurological Institute, Milan, Italy; Department of Clinical Neurophysiology (J.C.B.), Norfolk and Norwich University Hospital, Norfolk, UK
| | - Roy Poh
- From the MRC Centre for Neuromuscular Diseases (P.J.T., A.M.R., A.H., A.C., M.L., M.M.R.), Department of Neuropathology (Z.J.), and Department of Neurogenetics (R.P., J.P., H.H.), National Hospital for Neurology and Neurosurgery, UCL Institute of Neurology, Queen Square, London, UK; Clinic of Central and Peripheral Degenerative Neuropathies Unit (P.S., G.P., D.P.), Department of Clinical Neurosciences, IRCCS Foundation, C. Besta Neurological Institute, Milan, Italy; Department of Clinical Neurophysiology (J.C.B.), Norfolk and Norwich University Hospital, Norfolk, UK
| | - James Polke
- From the MRC Centre for Neuromuscular Diseases (P.J.T., A.M.R., A.H., A.C., M.L., M.M.R.), Department of Neuropathology (Z.J.), and Department of Neurogenetics (R.P., J.P., H.H.), National Hospital for Neurology and Neurosurgery, UCL Institute of Neurology, Queen Square, London, UK; Clinic of Central and Peripheral Degenerative Neuropathies Unit (P.S., G.P., D.P.), Department of Clinical Neurosciences, IRCCS Foundation, C. Besta Neurological Institute, Milan, Italy; Department of Clinical Neurophysiology (J.C.B.), Norfolk and Norwich University Hospital, Norfolk, UK
| | - Henry Houlden
- From the MRC Centre for Neuromuscular Diseases (P.J.T., A.M.R., A.H., A.C., M.L., M.M.R.), Department of Neuropathology (Z.J.), and Department of Neurogenetics (R.P., J.P., H.H.), National Hospital for Neurology and Neurosurgery, UCL Institute of Neurology, Queen Square, London, UK; Clinic of Central and Peripheral Degenerative Neuropathies Unit (P.S., G.P., D.P.), Department of Clinical Neurosciences, IRCCS Foundation, C. Besta Neurological Institute, Milan, Italy; Department of Clinical Neurophysiology (J.C.B.), Norfolk and Norwich University Hospital, Norfolk, UK
| | - Mary M Reilly
- From the MRC Centre for Neuromuscular Diseases (P.J.T., A.M.R., A.H., A.C., M.L., M.M.R.), Department of Neuropathology (Z.J.), and Department of Neurogenetics (R.P., J.P., H.H.), National Hospital for Neurology and Neurosurgery, UCL Institute of Neurology, Queen Square, London, UK; Clinic of Central and Peripheral Degenerative Neuropathies Unit (P.S., G.P., D.P.), Department of Clinical Neurosciences, IRCCS Foundation, C. Besta Neurological Institute, Milan, Italy; Department of Clinical Neurophysiology (J.C.B.), Norfolk and Norwich University Hospital, Norfolk, UK.
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22
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Weis J, Claeys KG, Roos A, Azzedine H, Katona I, Schröder JM, Senderek J. Towards a functional pathology of hereditary neuropathies. Acta Neuropathol 2017; 133:493-515. [PMID: 27896434 DOI: 10.1007/s00401-016-1645-y] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 11/10/2016] [Accepted: 11/13/2016] [Indexed: 12/11/2022]
Abstract
A growing number of hereditary neuropathies have been assigned to causative gene defects in recent years. The study of human nerve biopsy samples has contributed substantially to the discovery of many of these neuropathy genes. Genotype-phenotype correlations based on peripheral nerve pathology have provided a comprehensive picture of the consequences of these mutations. Intriguingly, several gene defects lead to distinguishable lesion patterns that can be studied in nerve biopsies. These characteristic features include the loss of certain nerve fiber populations and a large spectrum of distinct structural changes of axons, Schwann cells and other components of peripheral nerves. In several instances the lesion patterns are directly or indirectly linked to the known functions of the mutated gene. The present review is designed to provide an overview on these characteristic patterns. It also considers other aspects important for the manifestation and pathology of hereditary neuropathies including the role of inflammation, effects of chemotherapeutic agents and alterations detectable in skin biopsies.
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Affiliation(s)
- Joachim Weis
- Institute of Neuropathology, RWTH Aachen University Medical School, Pauwelsstr. 30, 52074, Aachen, Germany.
| | - Kristl G Claeys
- Institute of Neuropathology, RWTH Aachen University Medical School, Pauwelsstr. 30, 52074, Aachen, Germany
- Department of Neurology, RWTH Aachen University Medical School, Pauwelsstr. 30, 52074, Aachen, Germany
- Department of Neurology, University Hospitals Leuven and University of Leuven (KU Leuven), Leuven, Belgium
| | - Andreas Roos
- Institute of Neuropathology, RWTH Aachen University Medical School, Pauwelsstr. 30, 52074, Aachen, Germany
- Leibniz-Institut für Analytische Wissenschaften-ISAS-e.V., Otto-Hahn-Str. 6b, 44227, Dortmund, Germany
| | - Hamid Azzedine
- Institute of Neuropathology, RWTH Aachen University Medical School, Pauwelsstr. 30, 52074, Aachen, Germany
| | - Istvan Katona
- Institute of Neuropathology, RWTH Aachen University Medical School, Pauwelsstr. 30, 52074, Aachen, Germany
| | - J Michael Schröder
- Institute of Neuropathology, RWTH Aachen University Medical School, Pauwelsstr. 30, 52074, Aachen, Germany
| | - Jan Senderek
- Friedrich-Baur-Institute, Department of Neurology, Ludwig-Maximilians-University, Ziemssenstr. 1a, 80336, Munich, Germany.
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23
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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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24
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Tsai PC, Yang DM, Liao YC, Chiu TY, Kuo HC, Su YP, Guo YC, Soong BW, Lin KP, Liu YT, Lee YC. Clinical and biophysical characterization of 19 GJB1 mutations. Ann Clin Transl Neurol 2016; 3:854-865. [PMID: 27844031 PMCID: PMC5099531 DOI: 10.1002/acn3.347] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 08/08/2016] [Accepted: 08/08/2016] [Indexed: 12/12/2022] Open
Abstract
Objective Charcot–Marie–Tooth disease type X1 (CMTX1), which is caused by mutations in the gap junction (GJ) protein beta‐1 gene (GJB1), is the second most common form of Charcot–Marie–Tooth disease (CMT). GJB1 encodes the GJ beta‐1 protein (GJB1), which forms GJs within the myelin sheaths of peripheral nerves. The process by which GJB1 mutants cause neuropathy has not been fully elucidated. This study evaluated the biophysical characteristics of GJB1 mutants and their correlations with the clinical features of CMTX1 patients. Methods All patients with a validated GJB1 mutation were assessed using the Charcot–Marie–Tooth disease neuropathy score version 2 (CMTNS). The impacts of the mutations on the biophysical functions of GJB1 were characterized by assessing intracellular localization, expression patterns, and GJ Ca2+ permeability. Result Nineteen GJB1 mutations were identified in 24 patients with a clinical diagnosis of CMT. Six are novel mutations: p.L6S, p.I20F, p.I101Rfs*8, p.F153L, p.R215P, and p.D278V. Diverse pathological effects of the mutations were demonstrated, including reduced GJB1 expression, intracellular mislocalization, and altered GJ functions. GJB1 mutations that caused a complete loss of GJ Ca2+ permeability appeared to be associated with an earlier disease onset, whereas those resulting in preservation of GJ permeability and with predominant cell membrane expression tended to have a later onset and a milder phenotype. Interpretation This study demonstrated that the degree of loss of GJ function caused by the GJB1 mutations might contribute to the onset and severity of neuropathic symptoms in CMTX1.
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Affiliation(s)
- Pei-Chien Tsai
- Department of Neurology Taipei Veterans General Hospital Taipei 11217 Taiwan; Department of Neurology National Yang-Ming University School of Medicine Taipei 11221 Taiwan; Brain Research Center National Yang-Ming University Taipei 11221 Taiwan
| | - De-Ming Yang
- Microscopy Service Laboratory Basic Research Division Department of Medical Research and Education Taipei Veterans General Hospital Taipei 11217 Taiwan; Institute of Biophotonics School of Medical Technology & Engineering; Biophotonics and Molecular Imaging Research Center (BMIRC) National Yang-Ming University Taipei 11212 Taiwan
| | - Yi-Chu Liao
- Department of Neurology Taipei Veterans General Hospital Taipei 11217 Taiwan; Department of Neurology National Yang-Ming University School of Medicine Taipei 11221 Taiwan
| | - Tai-Yu Chiu
- Microscopy Service Laboratory Basic Research Division Department of Medical Research and Education Taipei Veterans General Hospital Taipei 11217 Taiwan; Institute of Biophotonics School of Medical Technology & Engineering; Biophotonics and Molecular Imaging Research Center (BMIRC) National Yang-Ming University Taipei 11212 Taiwan
| | - Hung-Chou Kuo
- Department of Neurology Chang Gung Memorial Hospital at Linkou Medical Center and Chang Gung University College of Medicine Taoyuan 33302 Taiwan
| | - Yu-Ping Su
- Department of Psychiatry Cathay General Hospital Taipei 10687 Taiwan; School of Medicine Fu-Jen Catholic University Taipei 24205 Taiwan
| | - Yuh-Cherng Guo
- Institute of Clinical Medicine National Yang-Ming University Taipei 11221 Taiwan; Neuroscience Laboratory Department of Neurology China Medical University Hospital Taichung 40447 Taiwan; School of Medicine College of Medicine China Medical University Taichung 40402 Taiwan
| | - Bing-Wen Soong
- Department of Neurology Taipei Veterans General Hospital Taipei 11217 Taiwan; Department of Neurology National Yang-Ming University School of Medicine Taipei 11221 Taiwan; Brain Research Center National Yang-Ming University Taipei 11221 Taiwan
| | - Kon-Ping Lin
- Department of Neurology Taipei Veterans General Hospital Taipei 11217 Taiwan; Department of Neurology National Yang-Ming University School of Medicine Taipei 11221 Taiwan
| | - Yo-Tsen Liu
- Department of Neurology Taipei Veterans General Hospital Taipei 11217 Taiwan; Department of Neurology National Yang-Ming University School of Medicine Taipei 11221 Taiwan
| | - Yi-Chung Lee
- Department of Neurology Taipei Veterans General Hospital Taipei 11217 Taiwan; Department of Neurology National Yang-Ming University School of Medicine Taipei 11221 Taiwan; Brain Research Center National Yang-Ming University Taipei 11221 Taiwan
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Jerath NU, Gutmann L, Reddy CG, Shy ME. Charcot-marie-tooth disease type 1X in women: Electrodiagnostic findings. Muscle Nerve 2016; 54:728-32. [PMID: 26873881 DOI: 10.1002/mus.25077] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Revised: 01/31/2016] [Accepted: 02/10/2016] [Indexed: 11/08/2022]
Abstract
INTRODUCTION Symptoms and signs in women with Charcot-Marie-Tooth disease type 1X (CMT1X) are often milder from those in men, but the available electrophysiologic evidence regarding CMT1X in women has been characterized in some patients as non-uniform or asymmetric. METHODS We retrospectively reviewed electrodiagnostic findings from 45 women and 31 men with CMT1X. RESULTS Motor nerve conduction parameters in CMT1X women were less abnormal (P < 0.05), and a wider range of motor conduction velocities (CVs) were seen in women (P < 0.001) compared with men. In women, nerve conduction studies showed lack of conduction block without temporal dispersion. Motor CVs were more frequently in the normal range in women compared with men. There was no significant relationship to age of presentation and motor CV or compound muscle action potential in women. CONCLUSION NCS parameters in CMT1X women did not demonstrate features suggestive of an acquired demyelinating neuropathy. Muscle Nerve, 2016 Muscle Nerve 54: -, 2016 Muscle Nerve 54: 728-732, 2016.
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Affiliation(s)
- Nivedita U Jerath
- Department of Neurology, University of Iowa Carver College of Medicine, 200 Hawkins Drive, Iowa City, Iowa, 52242, USA.
| | - Laurie Gutmann
- Department of Neurology, University of Iowa Carver College of Medicine, 200 Hawkins Drive, Iowa City, Iowa, 52242, USA
| | - Chandan G Reddy
- Department of Neurosurgery, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Michael E Shy
- Department of Neurology, University of Iowa Carver College of Medicine, 200 Hawkins Drive, Iowa City, Iowa, 52242, USA
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Xie C, Zhou X, Zhu D, Liu W, Wang X, Yang H, Li Z, Hao Y, Zhang GX, Guan Y. CNS involvement in CMTX1 caused by a novel connexin 32 mutation: a 6-year follow-up in neuroimaging and nerve conduction. Neurol Sci 2016; 37:1063-70. [PMID: 27098243 DOI: 10.1007/s10072-016-2537-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 02/24/2016] [Indexed: 12/29/2022]
Abstract
X-linked Charcot-Marie-Tooth disease, type 1 (CMTX1) is one of the most common inherited neurological disorders. Obvious CNS involvement is relatively rare in CMTX1 patients. A 24-year-old male with CMTX1 presented with three transient stroke-like attacks, and was followed up regularly for 6 years with brain MRI and electrophysiological examination. Transient symmetrical high signals on T2 imaging and restricted diffusion were found in bilateral deep white matter. Electrophysiological measurement revealed a sensorimotor peripheral neuropathy with slightly reduced nerve conduction velocities. A novel thymine to cytosine mutation at nucleotide position 445 in the connexin 32 allele of the GJB1 gene was identified. During the 6-year longitudinal study, patient's motor and sensory function did not worsen; radiological abnormalities correlated with episodes of CNS dysfunction and resolved after clinical recovery; electrophysiological records showed no obvious change. Little change in the patient's clinical, radiological and electrophysiological results over the follow-up reflected a slow disease progression.
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Affiliation(s)
- Chong Xie
- Department of Neurology, Changhai Hospital, Second Military Medical University, Shanghai, 200433, China
| | - Xiajun Zhou
- Department of Neurology, Renji Hospital, Shanghai Jiaotong University, 160 Pujian Road, Shanghai, China
| | - Desheng Zhu
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai, China
| | - Wei Liu
- Department of Neurology, Changhai Hospital, Second Military Medical University, Shanghai, 200433, China
| | - Xiaoqing Wang
- Department of Neurology, Changhai Hospital, Second Military Medical University, Shanghai, 200433, China
| | - Hong Yang
- Department of Neurology, Shanghai Yangpu Geriatric Hospital, Shanghai, China
| | - Zezhi Li
- Department of Neurology, Renji Hospital, Shanghai Jiaotong University, 160 Pujian Road, Shanghai, China
| | - Yong Hao
- Department of Neurology, Renji Hospital, Shanghai Jiaotong University, 160 Pujian Road, Shanghai, China
| | - Guang-Xian Zhang
- Department of Neurology, Thomas Jefferson University, 900 Walnut Street, Suite 300, Philadelphia, PA, 19107, USA.
| | - Yangtai Guan
- Department of Neurology, Changhai Hospital, Second Military Medical University, Shanghai, 200433, China
- Department of Neurology, Renji Hospital, Shanghai Jiaotong University, 160 Pujian Road, Shanghai, China
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Genotype–phenotype correlation of Charcot-Marie-Tooth type 1E patients with PMP22 mutations. Genes Genomics 2016. [DOI: 10.1007/s13258-016-0423-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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28
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Sun B, Chen ZH, Ling L, Li YF, Liu LZ, Yang F, Huang XS. Mutation Analysis of Gap Junction Protein Beta 1 and Genotype-Phenotype Correlation in X-linked Charcot-Marie-Tooth Disease in Chinese Patients. Chin Med J (Engl) 2016; 129:1011-6. [PMID: 27098783 PMCID: PMC4852665 DOI: 10.4103/0366-6999.180511] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Indexed: 11/04/2022] Open
Abstract
BACKGROUND Among patients with Charcot-Marie-Tooth disease (CMT), the X-linked variant (CMTX) caused by gap junction protein beta 1 (GJB1) gene mutation is the second most frequent type, accounting for approximately 90% of all CMTX. More than 400 mutations have been identified in the GJB1 gene that encodes connexin 32 (CX32). CX32 is thought to form gap junctions that promote the diffusion pathway between cells. GJB1 mutations interfere with the formation of the functional channel and impair the maintenance of peripheral myelin, and novel mutations are continually discovered. METHODS We included 79 unrelated patients clinically diagnosed with CMT at the Department of Neurology of the Chinese People's Liberation Army General Hospital from December 20, 2012, to December 31, 2015. Clinical examination, nerve conduction studies, and molecular and bioinformatics analyses were performed to identify patients with CMTX1. RESULTS Nine GJB1 mutations (c.283G>A, c.77C>T, c.643C>T, c.515C>T, c.191G>A, c.610C>T, c.490C>T, c.491G>A, and c.44G>A) were discovered in nine patients. Median motor nerve conduction velocities of all nine patients were < 38 m/s, resembling CMT Type 1. Three novel mutations, c.643C>T, c.191G>A, and c.610C>T, were revealed and bioinformatics analyses indicated high pathogenicity. CONCLUSIONS The three novel missense mutations within the GJB1 gene broaden the mutational diversity of CMT1X. Molecular analysis of family members and bioinformatics analyses of the afflicted patients confirmed the pathogenicity of these mutations.
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Affiliation(s)
- Bo Sun
- Department of Neurology, Chinese People's Liberation Army General Hospital, Beijing 100853, China
| | - Zhao-Hui Chen
- Department of Neurology, Chinese People's Liberation Army General Hospital, Beijing 100853, China
| | - Li Ling
- Department of Neurology, Chinese People's Liberation Army General Hospital, Beijing 100853, China
| | - Yi-Fan Li
- Department of Neurology, Chinese People's Liberation Army General Hospital, Beijing 100853, China
| | - Li-Zhi Liu
- Department of Neurology, Chinese People's Liberation Army General Hospital, Beijing 100853, China
| | - Fei Yang
- Department of Neurology, Chinese People's Liberation Army General Hospital, Beijing 100853, China
| | - Xu-Sheng Huang
- Department of Neurology, Chinese People's Liberation Army General Hospital, Beijing 100853, China
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Kennerson ML, Kim EJ, Siddell A, Kidambi A, Kim SM, Hong YB, Hwang SH, Chung KW, Choi BO. X-linked Charcot-Marie-Tooth disease type 6 (CMTX6) patients with a p.R158H mutation in the pyruvate dehydrogenase kinase isoenzyme 3 gene. J Peripher Nerv Syst 2016; 21:45-51. [DOI: 10.1111/jns.12160] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 01/09/2016] [Accepted: 01/18/2016] [Indexed: 11/26/2022]
Affiliation(s)
- Marina L. Kennerson
- Northcott Neuroscience Laboratory; ANZAC Research Institute & Sydney Medical School University of Sydney; Sydney Australia
- Molecular Medicine Laboratory; Concord Hospital; Sydney Australia
| | - Eun J. Kim
- Department of Neurology, Samsung Medical Center; Sungkyunkwan University School of Medicine; Seoul Korea
- Neuroscience Center; Samsung Medical Center; Seoul Korea
| | - Anna Siddell
- Northcott Neuroscience Laboratory; ANZAC Research Institute & Sydney Medical School University of Sydney; Sydney Australia
| | - Aditi Kidambi
- Northcott Neuroscience Laboratory; ANZAC Research Institute & Sydney Medical School University of Sydney; Sydney Australia
| | - Sung M. Kim
- Department of Biological Sciences; Kongju National University; Gongju Korea
| | - Young B. Hong
- Stem Cell & Regenerative Medicine Center; Kongju National University; Gongju Korea
- Neuroscience Center; Samsung Medical Center; 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
- Stem Cell & Regenerative Medicine Center; Kongju National University; Gongju Korea
- Neuroscience Center; Samsung Medical Center; Seoul Korea
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30
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Hong YB, Joo J, Hyun YS, Kwak G, Choi YR, Yeo HK, Jwa DH, Kim EJ, Mo WM, Nam SH, Kim SM, Yoo JH, Koo H, Park HT, Chung KW, Choi BO. A Mutation in PMP2 Causes Dominant Demyelinating Charcot-Marie-Tooth Neuropathy. PLoS Genet 2016; 12:e1005829. [PMID: 26828946 PMCID: PMC4735456 DOI: 10.1371/journal.pgen.1005829] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Accepted: 01/05/2016] [Indexed: 01/05/2023] Open
Abstract
Charcot-Marie-Tooth disease (CMT) is a heterogeneous group of peripheral neuropathies with diverse genetic causes. In this study, we identified p.I43N mutation in PMP2 from a family exhibiting autosomal dominant demyelinating CMT neuropathy by whole exome sequencing and characterized the clinical features. The age at onset was the first to second decades and muscle atrophy started in the distal portion of the leg. Predominant fatty replacement in the anterior and lateral compartment was similar to that in CMT1A caused by PMP22 duplication. Sural nerve biopsy showed onion bulbs and degenerating fibers with various myelin abnormalities. The relevance of PMP2 mutation as a genetic cause of dominant CMT1 was assessed using transgenic mouse models. Transgenic mice expressing wild type or mutant (p.I43N) PMP2 exhibited abnormal motor function. Electrophysiological data revealed that both mice had reduced motor nerve conduction velocities (MNCV). Electron microscopy revealed that demyelinating fibers and internodal lengths were shortened in both transgenic mice. These data imply that overexpression of wild type as well as mutant PMP2 also causes the CMT1 phenotype, which has been documented in the PMP22. This report might expand the genetic and clinical features of CMT and a further mechanism study will enhance our understanding of PMP2-associated peripheral neuropathy. Isolation of causative mutation is still challenging in genetic diseases with a variety of genetic causes. We discovered a mutation in a novel gene from a family exhibiting a peripheral neuropathy by virtue of next-generation sequencing. Although the family shows characteristic clinical features of hereditary motor and sensory neuropathy, we could not find a mutation from well-known genes. To demonstrate the clinical relevance of the novel gene, we generated transgenic mice, which carry the patients’ mutation within their chromosome. The transgenic mice exhibited the same phenotype as the patients including peripheral neuropathic symptoms and reduced locomotor function. We also observed the affected peripheral nervous system through electron microscopy. It seems that the expression of the mutant protein impairs the myelin of peripheral nervous system. These data might expand the genetic, clinical, and pathophysiological features of the peripheral neuropathy and a further investigation will enhance our understanding of disease in the peripheral nervous system.
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Affiliation(s)
- Young Bin Hong
- Stem Cell and Regenerative Medicine Center, Samsung Medical Center, Seoul, Korea
| | - Jaesoon Joo
- Department of Health Sciences and Technology, Samsung Advanced Institute for Health Science and Technology, Sungkyunkwan University, Seoul, Korea
| | - Young Se Hyun
- Department of Biological Science, Kongju National University, Gongju, Korea
| | - Geon Kwak
- Department of Health Sciences and Technology, Samsung Advanced Institute for Health Science and Technology, Sungkyunkwan University, Seoul, Korea
| | - Yu-Ri Choi
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Ha Kyung Yeo
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Dong Hwan Jwa
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Eun Ja Kim
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
- Neuroscience Center, Samsung Medical Center, Seoul, Korea
| | - Won Min Mo
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Soo Hyun Nam
- Department of Biological Science, Kongju National University, Gongju, Korea
| | - Sung Min Kim
- Department of Biological Science, Kongju National University, Gongju, Korea
| | - Jeong Hyun Yoo
- Department of Radiology, Ewha Womans University, School of Medicine, Seoul, Korea
| | - Heasoo Koo
- Department of Pathology, Ewha Womans University, School of Medicine, Seoul, Korea
| | - Hwan Tae Park
- Department of Physiology, College of Medicine, Dong-A University, Busan, Korea
| | - Ki Wha Chung
- Department of Biological Science, Kongju National University, Gongju, Korea
- * E-mail: (KWC); (BOC)
| | - Byung-Ok Choi
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
- Neuroscience Center, Samsung Medical Center, Seoul, Korea
- * E-mail: (KWC); (BOC)
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Wu N, Said S, Sabat S, Wicklund M, Stahl MC. Recurrent Episodes of Stroke-Like Symptoms in a Patient with Charcot-Marie-Tooth Neuropathy X Type 1. Case Rep Neurol 2015; 7:247-52. [PMID: 26955336 PMCID: PMC4777946 DOI: 10.1159/000442410] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Charcot-Marie-Tooth disease (CMT), also known as hereditary motor sensory neuropathy, is a heterogeneous group of disorders best known for causing inherited forms of peripheral neuropathy. The X-linked form, CMTX1, is caused by mutations in the gap junction protein beta 1 (GJB1) gene, expressed both by peripheral Schwann cells and central oligodendrocytes. Central manifestations are known but are rare, and there are few case reports of leukoencephalopathy with transient or persistent neurological deficits in patients with this CMT subtype. Here, we report the case of a man with multiple male and female family members affected by neuropathy who carries a pathologic mutation in GJB1. He has experienced three transient episodes with variable neurological deficits over the course of 7 years with corresponding changes on magnetic resonance imaging (MRI). This case illustrates CMT1X as a rare cause of transient neurological deficit and demonstrates the evolution of associated reversible abnormalities on MRI over time. To the best of our knowledge, this report provides the longest period of serial imaging in a single patient with this condition in the English language literature.
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Affiliation(s)
- Ning Wu
- Departments of Neurology, Pennsylvania State Milton S. Hershey Medical Center, Pennsylvania State College of Medicine, Hershey, Pa., USA
| | - Sarita Said
- Departments of Neurology, Pennsylvania State Milton S. Hershey Medical Center, Pennsylvania State College of Medicine, Hershey, Pa., USA
| | - Shyamsunder Sabat
- Departments of Radiology, Pennsylvania State Milton S. Hershey Medical Center, Pennsylvania State College of Medicine, Hershey, Pa., USA
| | - Matthew Wicklund
- Departments of Neurology, Pennsylvania State Milton S. Hershey Medical Center, Pennsylvania State College of Medicine, Hershey, Pa., USA
| | - Mark C Stahl
- Departments of Neurology, Pennsylvania State Milton S. Hershey Medical Center, Pennsylvania State College of Medicine, Hershey, Pa., USA; Departments of Neural and Behavioral Sciences, Pennsylvania State Milton S. Hershey Medical Center, Pennsylvania State College of Medicine, Hershey, Pa., USA
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Choi YR, Hong YB, Jung SC, Lee JH, Kim YJ, Park HJ, Lee J, Koo H, Lee JS, Jwa DH, Jung N, Woo SY, Kim SB, Chung KW, Choi BO. A novel homozygous MPV17 mutation in two families with axonal sensorimotor polyneuropathy. BMC Neurol 2015; 15:179. [PMID: 26437932 PMCID: PMC4595119 DOI: 10.1186/s12883-015-0430-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 09/14/2015] [Indexed: 12/12/2022] Open
Abstract
Background Mutations in MPV17 cause the autosomal recessive disorder mitochondrial DNA depletion syndrome 6 (MTDPS6), also called Navajo neurohepatopathy (NNH). Clinical features of MTDPS6 is infantile onset of progressive liver failure with seldom development of progressive neurologic involvement. Methods Whole exome sequencing (WES) was performed to isolate the causative gene of two unrelated neuropathy patients (9 and 13 years of age) with onset of the syndrome. Clinical assessments and biochemical analysis were performed. Results A novel homozygous mutation (p.R41Q) in MPV17 was found by WES in both patients. Both showed axonal sensorimotor polyneuropathy without liver and brain involvement, which is neurophysiologically similar to axonal Charcot-Marie-Tooth disease (CMT). A distal sural nerve biopsy showed an almost complete loss of the large and medium-sized myelinated fibers compatible with axonal neuropathy. An in vitro assay using mouse motor neuronal cells demonstrated that the abrogation of MPV17 significantly affected cell integrity. In addition, the expression of the mutant protein affected cell proliferation. These results imply that both the loss of normal function of MPV17 and the gain of detrimental effects of the mutant protein might affect neuronal function. Conclusion We report a novel homozygous mutation in MPV17 from two unrelated patients harboring axonal sensorimotor polyneuropathy without hepatoencephalopathy. This report expands the clinical spectrum of diseases caused by mutations of MPV17, and we recommend MPV17 gene screening for axonal peripheral neuropathies. Electronic supplementary material The online version of this article (doi:10.1186/s12883-015-0430-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yu-Ri Choi
- Department of Biochemistry, Ewha Womans University School of Medicine, Seoul, Korea.
| | - Young Bin Hong
- Stem Cell & Regenerative Medicine Center, Samsung Medical Center, Seoul, Korea.
| | - Sung-Chul Jung
- Department of Biochemistry, Ewha Womans University School of Medicine, Seoul, Korea.
| | - Ja Hyun Lee
- Department of Biological Science, Kongju National University, 56 Gonjudaehak-ro, Gongju, Chungnam, 314-701, Korea.
| | - Ye Jin Kim
- Department of Biological Science, Kongju National University, 56 Gonjudaehak-ro, Gongju, Chungnam, 314-701, Korea.
| | - Hyung Jun Park
- Department of Neurology, Ewha Womans University School of Medicine, Seoul, Korea.
| | - Jinho Lee
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon-ro, Gangnam-Gu, Seoul, 135-710, Korea.
| | - Heasoo Koo
- Department of Pathology, Ewha Womans University School of Medicine, Seoul, Korea.
| | - Ji-Su Lee
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon-ro, Gangnam-Gu, Seoul, 135-710, Korea.
| | - Dong Hwan Jwa
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon-ro, Gangnam-Gu, Seoul, 135-710, Korea.
| | - Namhee Jung
- Department of Biochemistry, Ewha Womans University School of Medicine, Seoul, Korea.
| | - So-Youn Woo
- Department of Microbiology, Ewha Womans University School of Medicine, Seoul, Korea.
| | - Sang-Beom Kim
- Department of Neurology, Kyung Hee University, College of Medicine, Seoul, Korea.
| | - Ki Wha Chung
- Department of Biological Science, Kongju National University, 56 Gonjudaehak-ro, Gongju, Chungnam, 314-701, Korea.
| | - Byung-Ok Choi
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon-ro, Gangnam-Gu, Seoul, 135-710, Korea. .,Neuroscience center, Samsung Medical Center, Seoul, Korea.
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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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34
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Connexins, gap junctions and peripheral neuropathy. Neurosci Lett 2015; 596:27-32. [DOI: 10.1016/j.neulet.2014.10.033] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 10/15/2014] [Accepted: 10/17/2014] [Indexed: 11/23/2022]
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35
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Xiao F, Tan JZ, Zhang X, Wang XF. A novel mutation in GJB1 (c.212T>G) in a Chinese family with X-linked Charcot-Marie-Tooth disease. J Clin Neurosci 2015; 22:513-8. [PMID: 25595958 DOI: 10.1016/j.jocn.2014.08.028] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Revised: 07/14/2014] [Accepted: 08/04/2014] [Indexed: 11/16/2022]
Abstract
Gap junction protein beta 1 (GJB1) gene mutations lead to X-linked Charcot-Marie-Tooth (CMTX) disease. We investigated a Chinese family with CMTX and identified a novel GJB1 point mutation. Clinical and electrophysiological features of the pedigree were examined, and sequence alterations of the coding region of GJB1 that encode connexin32 were determined by direct sequencing. Sequence alignment of the mutation site was performed using Clustal W. Mutation effects were analysed using PolyPhen-2, SIFT and Mutation Taster software. The three-dimensional structures of the mutant and wild-type proteins were predicted by modeling with SWISS MODEL online software. The affected family members displayed typical Charcot-Marie-Tooth phenotypes, but phenotypic heterogeneity was observed. Nerve conduction velocities of all affected patients were slow. Sequencing of GJB1 revealed a heterozygous T>G missense mutation at nucleotide 212 in the proband, the proband's mother and the proband's daughter. The affected male sibling of the proband displayed a hemizygous missense mutation with T>G transition at the identical position on the GJB1 gene. This mutation resulted in an amino acid change from isoleucine to serine that was predicted to lead to tertiary structural alterations that would disrupt the function of the GJB1 protein. A novel point mutation in GJB1 was detected, expanding the spectrum of GJB1 mutations known to be associated with CMTX.
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Affiliation(s)
- Fei Xiao
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, 1 You Yi Road, Chongqing 400016, China
| | - Jia-ze Tan
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, 1 You Yi Road, Chongqing 400016, China
| | - Xu Zhang
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, 1 You Yi Road, Chongqing 400016, China
| | - Xue-Feng Wang
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, 1 You Yi Road, Chongqing 400016, China.
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HONG YOUNGBIN, LEE JAHYUN, PARK HYUNGJUN, CHOI YURI, HYUN YOUNGSE, PARK JIHOON, KOO HEASOO, CHUNG KIWHA, CHOI BYUNGOK. A family with axonal sensorimotor polyneuropathy with TUBB3 mutation. Mol Med Rep 2014; 11:2729-34. [DOI: 10.3892/mmr.2014.3047] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Accepted: 11/03/2014] [Indexed: 11/06/2022] Open
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Hereditary motor and sensory neuropathies or Charcot–Marie–Tooth diseases: An update. J Neurol Sci 2014; 347:14-22. [DOI: 10.1016/j.jns.2014.10.013] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Revised: 10/06/2014] [Accepted: 10/08/2014] [Indexed: 11/15/2022]
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Intermediate Charcot-Marie-Tooth disease. Neurosci Bull 2014; 30:999-1009. [PMID: 25326399 DOI: 10.1007/s12264-014-1475-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Accepted: 06/19/2014] [Indexed: 01/15/2023] Open
Abstract
Charcot-Marie-Tooth (CMT) disease is a common neurogenetic disorder and its heterogeneity is a challenge for genetic diagnostics. The genetic diagnostic procedures for a CMT patient can be explored according to the electrophysiological criteria: very slow motor nerve conduction velocity (MNCV) (<15 m/s), slow MNCV (15-25 m/s), intermediate MNCV (25-45 m/s), and normal MNCV (>45 m/s). Based on the inheritance pattern, intermediate CMT can be divided into dominant (DI-CMT) and recessive types (RI-CMT). GJB1 is currently considered to be associated with X-linked DI-CMT, and MPZ, INF2, DNM2, YARS, GNB4, NEFL, and MFN2 are associated with autosomal DI-CMT. Moreover, GDAP1, KARS, and PLEKHG5 are associated with RI-CMT. Identification of these genes is not only important for patients and families but also provides new information about pathogenesis. It is hoped that this review will lead to a better understanding of intermediate CMT and provide a detailed diagnostic procedure for intermediate CMT.
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Hong YB, Jung SC, Lee J, Moon HS, Chung KW, Choi BO. Dynamic transcriptional events in distal sural nerve revealed by transcriptome analysis. Exp Neurobiol 2014; 23:169-72. [PMID: 24963282 PMCID: PMC4065831 DOI: 10.5607/en.2014.23.2.169] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2014] [Revised: 04/06/2014] [Accepted: 05/01/2014] [Indexed: 12/19/2022] Open
Abstract
Compared with biochemical information available about the diseases in the central nervous system, that for peripheral neuropathy is quite limited primarily due to the difficulties in obtaining samples. Characterization of the core pathology is a prerequisite to the development of personalized medicine for genetically heterogeneous diseases, such as hereditary motor and sensory neuropathy (HMSN). Here, we first documented the transcriptome profile of distal sural nerve obtained from HMSN patients. RNA-seq analysis revealed that over 12,000 genes are expressed in distal sural nerve. Among them 4,000 transcripts are novel and 10 fusion genes per sample were observed. Comparing dataset from whole exome sequencing revealed that over 1,500 transcriptional base modifications occur during transcription. These data implicate that dynamic alterations are generated when genetic information are transitioned in distal sural nerve. Although, we could not find significant alterations associated with HMSN, these data might provide crucial information about the pathophysiology of HMSN. Therefore, next step in the development of therapeutic strategy for HMSN might be unveiling biochemical and biophysical abnormalities derived from those potent variation.
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Affiliation(s)
- Young Bin Hong
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 135-710, Korea
| | - Sung-Chul Jung
- Department of Biochemistry, Ewha Womans University School of Medicine, Seoul 158-710, Korea
| | - Jinho Lee
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 135-710, Korea
| | - Heui-Soo Moon
- Department of Neurology, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul 110-746, Korea
| | - Ki Wha Chung
- Department of Biological Science, Kongju National University, Gongju 314-701, Korea
| | - Byung-Ok Choi
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 135-710, Korea
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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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Park MH, Woo HM, Hong YB, Park JH, Yoon BR, Park JM, Yoo JH, Koo H, Chae JH, Chung KW, Choi BO, Koo SK. Recessive C10orf2 mutations in a family with infantile-onset spinocerebellar ataxia, sensorimotor polyneuropathy, and myopathy. Neurogenetics 2014; 15:171-82. [PMID: 24816431 PMCID: PMC4102772 DOI: 10.1007/s10048-014-0405-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Accepted: 04/25/2014] [Indexed: 01/09/2023]
Abstract
Recessive mutations in chromosome 10 open reading frame 2 (C10orf2) are relevant in infantile-onset spinocerebellar ataxia (IOSCA). In this study, we investigated the causative mutation in a Korean family with combined phenotypes of IOSCA, sensorimotor polyneuropathy, and myopathy. We investigated recessive mutations in a Korean family with two individuals affected by IOSCA. Causative mutations were investigated using whole exome sequencing. Electrophysiological analyses and muscle and nerve biopsies were performed, along with magnetic resonance imaging (MRI) of the brain and lower extremities. Compound heterozygous mutations c.1460C>T and c.1485-1G>A in C10orf2 were identified as causative of IOSCA. Skeletal muscle showed mitochondrial DNA (mtDNA) deletions. Both patients showed a period of normal development until 12–15 months, followed by ataxia, athetosis, hearing loss, and intellectual disability. Electrophysiological findings indicated motor and sensory polyneuropathies. Muscle biopsy revealed variations in the size and shape of myofibers with scattered, small, and angulated degenerating myofibers containing abnormal mitochondria; these observations are consistent with myopathy and may be the result of mtDNA deletions. Sural nerve biopsy revealed an axonal neuropathy. High-signal-intensity lesions in the middle cerebellar peduncles were correlated with clinical severity, and MRI of the lower legs was compatible with the hypothesis of length-dependent axonal degeneration. We identified novel compound heterozygous mutations of the C10orf2 gene as the cause of IOSCA with sensorimotor polyneuropathy and myopathy. Signs of motor neuropathy and myopathy were discovered for the first time in IOSCA patients with C10orf2 mutations. These results suggest that the clinical spectrum of IOSCA caused by C10orf2 mutations may be more variable than previously reported.
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Affiliation(s)
- Mi-Hyun Park
- Division of Intractable Diseases, Center for Biomedical Sciences, National Institute of Health, Osong Health Technology Administration Complex 643, Yeonje-ri, Osong-eup, Cheongwon-gun, Chungcheongbuk-do, 363-951, South Korea
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Hong YB, Lee JH, Park JM, Choi YR, Hyun YS, Yoon BR, Yoo JH, Koo H, Jung SC, Chung KW, Choi BO. A compound heterozygous mutation in HADHB gene causes an axonal Charcot-Marie-tooth disease. BMC MEDICAL GENETICS 2013; 14:125. [PMID: 24314034 PMCID: PMC4029087 DOI: 10.1186/1471-2350-14-125] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Accepted: 11/28/2013] [Indexed: 12/31/2022]
Abstract
Background Charcot-Marie-Tooth disease (CMT) is a heterogeneous disorder of the peripheral nervous system. So far, mutations in hydroxyacyl-CoA dehydrogenase/3-ketoacyl-CoA thiolase/enoyl-CoA hydratase (trifunctional protein), beta subunit (HADHB) gene exhibit three distinctive phenotypes: severe neonatal presentation with cardiomyopathy, hepatic form with recurrent hypoketotic hypoglycemia, and later-onset axonal sensory neuropathy with episodic myoglobinuria. Methods To identify the causative and characterize clinical features of a Korean family with motor and sensory neuropathies, whole exome study (WES), histopathologic study of distal sural nerve, and lower limb MRIs were performed. Results WES revealed that a compound heterozygous mutation in HADHB is the causative of the present patients. The patients exhibited an early-onset axonal sensorimotor neuropathy without episodic myoglobinuria, and showed typical clinical and electrophysiological features of CMT including predominant distal muscle weakness and atrophy. Histopathologic findings of sural nerve were compatible with an axonal CMT neuropathy. Furthermore, they didn’t exhibit any other symptoms of the previously reported HADHB patients. Conclusions These data implicate that mutation in HADHB gene can also cause early-onset axonal CMT instead of typical manifestations in mitochondrial trifunctional protein (MTP) deficiency. Therefore, this study is the first report of a new subtype of autosomal recessive axonal CMT by a compound heterozygous mutation in HADHB, and will expand the clinical and genetic spectrum of HADHB.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Ki Wha Chung
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Ilwon-dong Gangnam-Gu, Seoul 135-710, Korea.
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Suh BC, Hong YB, Nakhro K, Nam SH, Chung KW, Choi BO. Early-onset severe hereditary sensory and autonomic neuropathy type 1 with S331F SPTLC1 mutation. Mol Med Rep 2013; 9:481-6. [PMID: 24247255 DOI: 10.3892/mmr.2013.1808] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Accepted: 11/08/2013] [Indexed: 11/06/2022] Open
Abstract
Hereditary sensory and autonomic neuropathy type I (HSAN I) is an autosomal dominant disease characterized by prominent sensory impairment, resulting in foot ulcers or amputations and has a juvenile to adult onset. The major underlying causes of HSAN I are mutations in SPTLC1, which encodes the first subunit of serine palmitoyltransferase (SPT). To date, there have been no reports with regard to an HSAN patient of Korean origin. In this report we discussed an HSAN I patient with a missense mutation in SPTLC1 (c.992C>T: p.S331F). The patient had noticed frequent falls, lower leg weakness and hand tremors at age five. The patient also presented with foot ulcers, muscle hypotrophy, cataracts, hoarseness, vocal cord palsy and respiratory difficulties and succumbed to the condition at the age of 28 years. In accordance with previous reports, a mutation in Ser331 in the present patient was associated with early-onset and a severe phenotype. Therefore, Ser331 in SPTLC1 is a crucial amino acid, which characterizes the HSAN I phenotype.
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Affiliation(s)
- Bum Chun Suh
- Department of Neurology, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul 110-746, Republic of Korea
| | - Young Bin Hong
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 135-71, Republic of Korea
| | - Khriezhanuo Nakhro
- Department of Biological Science, Kongju National University, Gongju, Chungnam 314-701, Republic of Korea
| | - Soo Hyun Nam
- Department of Biological Science, Kongju National University, Gongju, Chungnam 314-701, Republic of Korea
| | - Ki Wha Chung
- Department of Biological Science, Kongju National University, Gongju, Chungnam 314-701, Republic of Korea
| | - Byung-Ok Choi
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 135-71, Republic of Korea
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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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Martikainen MH, Majamaa K. Novel GJB1 mutation causing adult-onset Charcot-Marie-Tooth disease in a female patient. Neuromuscul Disord 2013; 23:899-901. [PMID: 23838279 DOI: 10.1016/j.nmd.2013.06.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 06/02/2013] [Accepted: 06/11/2013] [Indexed: 11/24/2022]
Abstract
Charcot-Marie-Tooth disease (CMT), which is the eponym for hereditary motor and sensory neuropathy (HMSN), affects ∼1 in 2500 individuals. The most common subtype of X-linked CMT, CMTX1, is caused by mutations in GJB1, the gene encoding connexin 32, a gap junction protein in myelinated Schwann cells. We report a woman, who presented at the age of 56 years with gait unsteadiness and tingling in her feet. Clinical investigation revealed impaired sensation to pinprick, light touch and vibration in her distal lower limbs. Ankle reflexes were bilaterally absent. Sequencing revealed a novel heterozygous c.712C>T (p.R238C) mutation in the GJB1 gene. This mutation is predicted to result in the loss of disulfide bonds and thus in abnormal protein structure. In this woman, the reported novel GJB1 mutation resulted in sensory abnormalities, slowly progressive loss of distal lower limb strength, and notable loss of balance, with onset of symptoms late in adult age.
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Affiliation(s)
- Mika H Martikainen
- University of Turku and Turku University Hospital, Division of Clinical Neurosciences, Turku, Finland.
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Nakhro K, Park JM, Choi BO, Chung KW. Missense mutations ofmitofusin 2in axonal Charcot–Marie–Tooth neuropathy: polymorphic or incomplete penetration? Anim Cells Syst (Seoul) 2013. [DOI: 10.1080/19768354.2013.814587] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
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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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Crone C, Krarup C. Neurophysiological approach to disorders of peripheral nerve. HANDBOOK OF CLINICAL NEUROLOGY 2013; 115:81-114. [PMID: 23931776 DOI: 10.1016/b978-0-444-52902-2.00006-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Disorders of the peripheral nerve system (PNS) are heterogeneous and may involve motor fibers, sensory fibers, small myelinated and unmyelinated fibers and autonomic nerve fibers, with variable anatomical distribution (single nerves, several different nerves, symmetrical affection of all nerves, plexus, or root lesions). Furthermore pathological processes may result in either demyelination, axonal degeneration or both. In order to reach an exact diagnosis of any neuropathy electrophysiological studies are crucial to obtain information about these variables. Conventional electrophysiological methods including nerve conduction studies and electromyography used in the study of patients suspected of having a neuropathy and the significance of the findings are discussed in detail and more novel and experimental methods are mentioned. Diagnostic considerations are based on a flow chart classifying neuropathies into eight categories based on mode of onset, distribution, and electrophysiological findings, and the electrophysiological characteristics in each type of neuropathy are discussed.
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Affiliation(s)
- Clarissa Crone
- Department of Clinical Neurophysiology, Rigshospitalet and University of Copenhagen, Copenhagen, Denmark
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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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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 muscle atrophy and weakness, areflexia, and variable sensory abnormalities; central nervous system manifestations occur, too. Affected males have moderate to severe symptoms, whereas heterozygous females are usually less affected. Neurophysiology shows intermediate slowing of conduction and distal axonal loss. Nerve biopsies show more prominent axonal degeneration than de/remyelination. More than 400 different mutations in GJB1, the gene that encodes the gap junction (GJ) protein connexin32 (Cx32), cause CMT1X. 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. An effective therapy remains to be developed.
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Affiliation(s)
- Steven S Scherer
- Department of Neurology, The Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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