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Espinoza KS, Hermanson KN, Beard CA, Schwartz NU, Snider JM, Low BE, Wiles MV, Hannun YA, Obeid LM, Snider AJ. A novel HSPB1 S139F mouse model of Charcot-Marie-Tooth Disease. Prostaglandins Other Lipid Mediat 2023; 169:106769. [PMID: 37625781 PMCID: PMC10843462 DOI: 10.1016/j.prostaglandins.2023.106769] [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: 05/31/2023] [Revised: 08/01/2023] [Accepted: 08/22/2023] [Indexed: 08/27/2023]
Abstract
Charcot-Marie-Tooth Disease (CMT) is a commonly inherited peripheral polyneuropathy. Clinical manifestations for this disease include symmetrical distal polyneuropathy, altered deep tendon reflexes, distal sensory loss, foot deformities, and gait abnormalities. Genetic mutations in heat shock proteins have been linked to CMT2. Specifically, mutations in the heat shock protein B1 (HSPB1) gene encoding for heat shock protein 27 (Hsp27) have been linked to CMT2F and distal hereditary motor and sensory neuropathy type 2B (dHMSN2B) subtype. The goal of the study was to examine the role of an endogenous mutation in HSPB1 in vivo and to define the effects of this mutation on motor function and pathology in a novel animal model. As sphingolipids have been implicated in hereditary and sensory neuropathies, we examined sphingolipid metabolism in central and peripheral nervous tissues in 3-month-old HspS139F mice. Though sphingolipid levels were not altered in sciatic nerves from HspS139F mice, ceramides and deoxyceramides, as well as sphingomyelins (SMs) were elevated in brain tissues from HspS139F mice. Histology was utilized to further characterize HspS139F mice. HspS139F mice exhibited no alterations to the expression and phosphorylation of neurofilaments, or in the expression of acetylated α-tubulin in the brain or sciatic nerve. Interestingly, HspS139F mice demonstrated cerebellar demyelination. Locomotor function, grip strength and gait were examined to define the role of HspS139F in the clinical phenotypes associated with CMT2F. Gait analysis revealed no differences between HspWT and HspS139F mice. However, both coordination and grip strength were decreased in 3-month-old HspS139F mice. Together these data suggest that the endogenous S139F mutation in HSPB1 may serve as a mouse model for hereditary and sensory neuropathies such as CMT2F.
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Affiliation(s)
- Keila S Espinoza
- Department of Physiology, University of Arizona, Tucson, AZ 85721, USA
| | - Kyra N Hermanson
- Department of Physiology, University of Arizona, Tucson, AZ 85721, USA
| | - Cameron A Beard
- School of Nutritional Sciences and Wellness, University of Arizona, Tucson, AZ 85721, USA
| | - Nicholas U Schwartz
- Department of Neurology, Stanford University Medical Center, Stanford, CA 94304, USA
| | - Justin M Snider
- School of Nutritional Sciences and Wellness, University of Arizona, Tucson, AZ 85721, USA; University of Arizona Cancer Center, University of Arizona, Tucson, AZ 85721, USA
| | - Benjamin E Low
- Technology Evaluation and Development, The Jackson Laboratory, Bar Harbor, ME, USA; Genetic Resource Science, The Jackson Laboratory, Bar Harbor, ME, USA
| | - Michael V Wiles
- Technology Evaluation and Development, The Jackson Laboratory, Bar Harbor, ME, USA
| | - Yusuf A Hannun
- Department of Medicine and Stony Brook Cancer Center, Stony Brook, NY 11794, USA; Northport Veterans Affairs Medical Center, Northport, NY 11768, USA
| | - Lina M Obeid
- Department of Medicine and Stony Brook Cancer Center, Stony Brook, NY 11794, USA; Northport Veterans Affairs Medical Center, Northport, NY 11768, USA
| | - Ashley J Snider
- School of Nutritional Sciences and Wellness, University of Arizona, Tucson, AZ 85721, USA; University of Arizona Cancer Center, University of Arizona, Tucson, AZ 85721, USA.
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Aslam MS, Kim YJ, Qian L. A Retrospective Bayesian Design of Experiment (B-DOE) on Drug Reposition Candidates for Treatment of Charcot-Marie-Tooth Neuropathy. MULTIDISCIPLINARY APPLICATIONS OF NATURAL SCIENCE FOR DRUG DISCOVERY AND INTEGRATIVE MEDICINE 2023:275-290. [DOI: 10.4018/978-1-6684-9463-9.ch008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
Bayesian design of experiment (B-DOE) uses the principle of Bayesian Epistemology that explain the evidence as a logical-probalistic coherence on the basis of rational degrees of belief (or degrees of confidence). The researcher has design the (B-DOE) using Multilevel Hierarchy (MH), and data that may be obtained at the weak to moderate evidence level (literature, biological. Mechanism, computational and retrospective) may be helpful to identify bioactive compounds for treating (CMT) and provide the knowledge on pathogenesis, prognostic of the disease and collective mechanism of drug of action. The investigators will classify the evidence on the basis of hierarchy as moderate and weak, which will ultimately help to study new promising bioactive compounds potentially able to solve some of the issues related to CMT.
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Affiliation(s)
| | - Yun Jin Kim
- School of Traditional Chinese Medicine, Xiamen University Malaysia, Malaysia
| | - Linchao Qian
- School of Traditional Chinese Medicine, Xiamen University Malaysia, Malaysia
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Truong AT, Luong ATL, Nguyen LH, Nguyen HV, Nguyen DN, Nguyen NTM. A novel single-point mutation of NEFH and biallelic SACS mutation presenting as intermediate form Charcot-Marie-Tooth: A case report in Vietnam. Surg Neurol Int 2022; 13:553. [PMID: 36600740 PMCID: PMC9805609 DOI: 10.25259/sni_803_2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 11/04/2022] [Indexed: 11/27/2022] Open
Abstract
Background Charcot-Marie-Tooth disease (CMT) is among the most common group of inherited neuromuscular diseases. SACS mutations were demonstrated to cause autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS). However, there have been few case reports regarding to NEFH and SACS gene mutation to CMT in Vietnamese patients, and the diagnosis of CMT and ARSACS in the clinical setting still overlapped. Case Description We report two patients presenting with sensorimotor neuropathy without cerebellar ataxia, spasticity and other neurological features, being diagnosed with intermediate form CMT by electrophysiological and clinical examination and neuroimaging. By whole-exome sequencing panel of two affected members, and PCR Sanger on NEFH and SACS genes to confirm the presence of selected variants on their parents, we identified a novel missense variant NEFH c.1925C>T (inherited from the mother) in an autosomal dominant heterozygous state, and two recessive SACS variants (SACS c.13174C>T, causing missense variant, and SACS c.11343del, causing frameshift variant) (inherited one from the mother and another from the father) in these two patients. Clinical and electrophysiological findings on these patients did not match classical ARSACS. To the best of our knowledge, this is the first case report of two affected siblings diagnosed with CMT carrying both a novel NEFH variant and biallelic SACS variants. Conclusion We concluded that this novel NEFH variant is likely benign, and biallelic SACS mutation (c.13174C>T and c.11343del) is likely pathogenic for intermediate form CMT. This study is also expected to emphasize the current knowledge of intermediate form CMT, ARSACS, and the phenotypic spectrum of NEFH-related and SACS-related disorders. We expect to give a new understanding of CMT; however, further research should be conducted to provide a more thorough knowledge of the pathogenesis of CMT in the future.
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Affiliation(s)
- Anh Tuan Truong
- Department of Clinical Medicine, Nam Dinh University of Nursing, Nam Dinh, Vietnam
| | - Anh Thi Lan Luong
- Department of Medical Biology and Genetics, Hanoi Medical University, Hanoi, Vietnam
| | - Linh Hai Nguyen
- Department of Neurology, Hanoi Medical University, Hanoi, Vietnam.,Corresponding author: Linh Hai Nguyen, Department of Neurology, Hanoi Medical University, Hanoi, Vietnam.
| | - Huong Van Nguyen
- Department of Neurology, Hanoi Medical University, Hanoi, Vietnam
| | - Diep Ngoc Nguyen
- Institute of Theoretical and Applied Research (ITAR), School of Medicine and Pharmacy, Duy Tan University, Da Nang, Vietnam
| | - Ngoc Thi Minh Nguyen
- Department of Medical Biology and Genetics, Hanoi Medical University, Hanoi, Vietnam
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Peck J, Poppino K, Sparagana S, Rampy P, Freeman S, Jo CH, Sucato D. Use of transcranial motor-evoked potentials to provide reliable intraoperative neuromonitoring for the Charcot-Marie-Tooth population undergoing spine deformity surgery. Spine Deform 2022; 10:411-418. [PMID: 34561841 DOI: 10.1007/s43390-021-00409-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 08/28/2021] [Indexed: 11/30/2022]
Abstract
PURPOSE Intraoperative neuromonitoring (IONM) has historically been difficult to obtain in patients with Charcot-Marie-Tooth (CMT) disease. Transcranial motor-evoked potentials (TcMEPs) have been found to be safe and effective for other spinal deformity patients. Our objective was to determine the effectiveness of TcMEP monitoring in patients with CMT. METHODS An IRB-approved, retrospective review of CMT patients undergoing spinal deformity surgery assessing TcMEP, somatosensory-evoked potential (SSEP), and neurogenic motor evoked potential (NMEP) IONM was performed. A 2:1 matched cohort control group of idiopathic spinal deformity patients was used. A waveform grading system was applied to review baseline TcMEP reliability and quality, which was validated via intraclass correlation coefficient amongst five raters. RESULTS Twenty-three CMT patients (26 surgical cases) were identified. The use of TcMEP improved the ability to obtain baseline IONM when compared to SSEP (83% vs. 20%; p < 0.001) and NMEP (83% vs. 18%; p = 0.003). Baseline monitoring was obtained less often for CMT patients using SSEP (20% vs. 100%; p < 0.001) and TcMEP (83% vs. 100%; p = 0.111) compared to idiopathic patients. Sweep length (time from stimulation waveform evaluation) and maximum stimulation voltage were higher in the CMT group (289 ms vs. 111 ms p = 0.007 and 740 V vs. 345 V p = 0.089, respectively). CONCLUSION TcMEP monitoring significantly improves the ability to provide IONM for CMT patients undergoing spinal deformity surgery. Utilizing longer sweep lengths enhances the ability to attain baseline TcMEP readings, allowing surgeons to more safely proceed with surgery for these complex patients. LEVEL OF EVIDENCE Therapeutic-Level III.
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Affiliation(s)
- Jeffrey Peck
- Division of Pediatric Orthopaedic Surgery, Children's National Hospital, Washington, DC, 20010, USA
| | - Kiley Poppino
- Department of Orthopaedic Surgery, Texas Scottish Rite Hospital for Children, University of Texas Southwestern Medical Center, 2222 Welborn Street, Dallas, TX, 75219, USA
| | - Steven Sparagana
- Department of Neurology and Rehabilitation Medicine, Texas Scottish Rite Hospital, University of Texas Southwestern Medical Center, Dallas, TX, 75219, USA
| | - Patricia Rampy
- Department of Neurology and Rehabilitation Medicine, Texas Scottish Rite Hospital, University of Texas Southwestern Medical Center, Dallas, TX, 75219, USA
| | - Spencer Freeman
- Department of Neurology and Rehabilitation Medicine, Texas Scottish Rite Hospital, University of Texas Southwestern Medical Center, Dallas, TX, 75219, USA
| | - Chan-Hee Jo
- Research Department, Texas Scottish Rite Hospital, Dallas, TX, 75219, USA
| | - Daniel Sucato
- Department of Orthopaedic Surgery, Texas Scottish Rite Hospital for Children, University of Texas Southwestern Medical Center, 2222 Welborn Street, Dallas, TX, 75219, USA.
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Tzou FY, Wen JK, Yeh JY, Huang SY, Chen GC, Chan CC. Drosophila as a model to study autophagy in neurodegenerative diseases and digestive tract. IUBMB Life 2021; 74:339-360. [PMID: 34874101 DOI: 10.1002/iub.2583] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Revised: 11/08/2021] [Accepted: 11/15/2021] [Indexed: 12/20/2022]
Abstract
Autophagy regulates cellular homeostasis by degrading and recycling cytosolic components and damaged organelles. Disruption of autophagic flux has been shown to induce or facilitate neurodegeneration and accumulation of autophagic vesicles is overt in neurodegenerative diseases. The fruit fly Drosophila has been used as a model system to identify new factors that regulate physiology and disease. Here we provide a historical perspective of how the fly models have offered mechanistic evidence to understand the role of autophagy in neurodegenerative diseases including Alzheimer's disease, Parkinson's disease, Charcot-Marie-Tooth neuropathy, and polyglutamine disorders. Autophagy also plays a pivotal role in maintaining tissue homeostasis and protecting organism health. The gastrointestinal tract regulates organism health by modulating food intake, energy balance, and immunity. Growing evidence is strengthening the link between autophagy and digestive tract health in recent years. Here, we also discuss how the fly models have advanced the understanding of digestive physiology regulated by autophagy.
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Affiliation(s)
- Fei-Yang Tzou
- Graduate Institute of Physiology, National Taiwan University, Taipei, Taiwan
| | - Jung-Kun Wen
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Jui-Yu Yeh
- Graduate Institute of Physiology, National Taiwan University, Taipei, Taiwan
| | - Shu-Yi Huang
- Department of Medical Research, National Taiwan University Hospital, Taipei, Taiwan
| | - Guang-Chao Chen
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Chih-Chiang Chan
- Graduate Institute of Physiology, National Taiwan University, Taipei, Taiwan
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Park NY, Kwak G, Doo HM, Kim HJ, Jang SY, Lee YI, Choi BO, Hong YB. Farnesol Ameliorates Demyelinating Phenotype in a Cellular and Animal Model of Charcot-Marie-Tooth Disease Type 1A. Curr Issues Mol Biol 2021; 43:2011-2021. [PMID: 34889893 PMCID: PMC8928981 DOI: 10.3390/cimb43030138] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 10/29/2021] [Accepted: 11/10/2021] [Indexed: 01/05/2023] Open
Abstract
Charcot-Marie-Tooth disease (CMT) is a genetically heterogeneous disease affecting the peripheral nervous system that is caused by either the demyelination of Schwann cells or degeneration of the peripheral axon. Currently, there are no treatment options to improve the degeneration of peripheral nerves in CMT patients. In this research, we assessed the potency of farnesol for improving the demyelinating phenotype using an animal model of CMT type 1A. In vitro treatment with farnesol facilitated myelin gene expression and ameliorated the myelination defect caused by PMP22 overexpression, the major causative gene in CMT. In vivo administration of farnesol enhanced the peripheral neuropathic phenotype, as shown by rotarod performance in a mouse model of CMT1A. Electrophysiologically, farnesol-administered CMT1A mice exhibited increased motor nerve conduction velocity and compound muscle action potential compared with control mice. The number and diameter of myelinated axons were also increased by farnesol treatment. The expression level of myelin protein zero (MPZ) was increased, while that of the demyelination marker, neural cell adhesion molecule (NCAM), was reduced by farnesol administration. These data imply that farnesol is efficacious in ameliorating the demyelinating phenotype of CMT, and further elucidation of the underlying mechanisms of farnesol’s effect on myelination might provide a potent therapeutic strategy for the demyelinating type of CMT.
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Affiliation(s)
- Na-Young Park
- Department of Translational Biomedical Sciences, Graduate School of Dong-A University, Busan 49201, Korea;
| | - Geon Kwak
- Department of Health Sciences and Technology, SAIHST, Sungkyunkwan University, Seoul 06351, Korea; (G.K.); (H.-M.D.); (H.-J.K.)
| | - Hyun-Myung Doo
- Department of Health Sciences and Technology, SAIHST, Sungkyunkwan University, Seoul 06351, Korea; (G.K.); (H.-M.D.); (H.-J.K.)
| | - Hye-Jin Kim
- Department of Health Sciences and Technology, SAIHST, Sungkyunkwan University, Seoul 06351, Korea; (G.K.); (H.-M.D.); (H.-J.K.)
| | - So-Young Jang
- Departments of Biochemistry, College of Medicine, Dong-A University, Busan 49201, Korea;
| | - Yun-Il Lee
- Well Aging Research Center, Division of Biotechnology, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea;
| | - Byung-Ok Choi
- Department of Health Sciences and Technology, SAIHST, Sungkyunkwan University, Seoul 06351, Korea; (G.K.); (H.-M.D.); (H.-J.K.)
- Samsung Medical Center, Department of Neurology, Sungkyunkwan University School of Medicine, Seoul 06351, Korea
- Correspondence: (B.-O.C.); (Y.-B.H.); Tel.: +82-2-3410-1296 (B.-O.C.); +82-51-240-2762 (Y.-B.H.); Fax: +82-3410-0052 (B.-O.C.); +82-51-240-2971 (Y.-B.H.)
| | - Young-Bin Hong
- Department of Translational Biomedical Sciences, Graduate School of Dong-A University, Busan 49201, Korea;
- Departments of Biochemistry, College of Medicine, Dong-A University, Busan 49201, Korea;
- Correspondence: (B.-O.C.); (Y.-B.H.); Tel.: +82-2-3410-1296 (B.-O.C.); +82-51-240-2762 (Y.-B.H.); Fax: +82-3410-0052 (B.-O.C.); +82-51-240-2971 (Y.-B.H.)
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Hong JM, Jeon H, Choi YC, Cho H, Hong YB, Park HJ. A Compound Heterozygous Pathogenic Variant in B4GALNT1 Is Associated With Axonal Charcot-Marie-Tooth Disease. J Clin Neurol 2021; 17:534-540. [PMID: 34595861 PMCID: PMC8490901 DOI: 10.3988/jcn.2021.17.4.534] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 06/08/2021] [Accepted: 06/08/2021] [Indexed: 11/17/2022] Open
Abstract
Background and Purpose Pathogenic variants in B4GALNT1 have been reported to cause hereditary spastic paraplegia 26. This study has revealed that a novel compound heterozygous pathogenic variant in B4GALNT1 is associated with axonal Charcot-Marie-Tooth disease (CMT). Methods Whole-exome sequencing (WES) was used to identify the causative factors and characterize the clinical features of a Korean family with sensorimotor polyneuropathy. Functional assessment of the mutant genes was performed using a motor neuron cell line. Results The WES revealed a compound heterozygous pathogenic variant (c.128dupC and c.451G>A) in B4GALNT1 as the causative of the present patient, a 53-year-old male who presented with axonal sensorimotor polyneuropathy and cognitive impairment without spasticity. The electrodiagnostic study showed axonal sensorimotor polyneuropathy. B4GALNT1 was critical to the proliferation of motor neuron cells. The compensation assay revealed that the pathogenic variants might affect the enzymatic activity of B4GALNT1. Conclusions This study is the first to identify a case of autosomal recessive axonal CMT associated with a compound heterozygous pathogenic variant in B4GALNT1. This finding expands the clinical and genetic spectra of peripheral neuropathy.
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Affiliation(s)
- Ji Man Hong
- Department of Neurology, Yongin Severance Hospital, Yonsei University College of Medicine, Yongin, Korea
| | - Hyeonjin Jeon
- Department of Biochemistry, College of Medicine, Dong-A University, Busan, Korea.,Department of Translational Biomedical Sciences, Graduate School of Dong-A University, Busan, Korea
| | - Young Chul Choi
- Department of Neurology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Hanna Cho
- Department of Neurology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Young Bin Hong
- Department of Biochemistry, College of Medicine, Dong-A University, Busan, Korea.,Department of Translational Biomedical Sciences, Graduate School of Dong-A University, Busan, Korea.
| | - Hyung Jun Park
- Department of Neurology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
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McCray BA, Scherer SS. Axonal Charcot-Marie-Tooth Disease: from Common Pathogenic Mechanisms to Emerging Treatment Opportunities. Neurotherapeutics 2021; 18:2269-2285. [PMID: 34606075 PMCID: PMC8804038 DOI: 10.1007/s13311-021-01099-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/28/2021] [Indexed: 01/12/2023] Open
Abstract
Inherited peripheral neuropathies are a genetically and phenotypically diverse group of disorders that lead to degeneration of peripheral neurons with resulting sensory and motor dysfunction. Genetic neuropathies that primarily cause axonal degeneration, as opposed to demyelination, are most often classified as Charcot-Marie-Tooth disease type 2 (CMT2) and are the focus of this review. Gene identification efforts over the past three decades have dramatically expanded the genetic landscape of CMT and revealed several common pathological mechanisms among various forms of the disease. In some cases, identification of the precise genetic defect and/or the downstream pathological consequences of disease mutations have yielded promising therapeutic opportunities. In this review, we discuss evidence for pathogenic overlap among multiple forms of inherited neuropathy, highlighting genetic defects in axonal transport, mitochondrial dynamics, organelle-organelle contacts, and local axonal protein translation as recurrent pathological processes in inherited axonal neuropathies. We also discuss how these insights have informed emerging treatment strategies, including specific approaches for single forms of neuropathy, as well as more general approaches that have the potential to treat multiple types of neuropathy. Such therapeutic opportunities, made possible by improved understanding of molecular and cellular pathogenesis and advances in gene therapy technologies, herald a new and exciting phase in inherited peripheral neuropathy.
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Affiliation(s)
- Brett A. McCray
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205 USA
| | - Steven S. Scherer
- Department of Neurology, The University of Pennsylvania, Philadelphia, PA 19104 USA
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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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Kang JH. Quantitative Analysis of Electrophysiological Characteristics of CIDP and CMT Type 1: Sensory Nerve Research. KOREAN JOURNAL OF CLINICAL LABORATORY SCIENCE 2021. [DOI: 10.15324/kjcls.2021.53.2.151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Affiliation(s)
- Ji-Hyuk Kang
- Department of Biomedical Laboratory Science, College of Health and Medical Science, Daejeon University, Daejeon, Korea
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Aruta F, Severi D, Iovino A, Spina E, Barghigiani M, Ruggiero L, Iodice R, Santorelli FM, Manganelli F, Tozza S. Proximal weakness involvement in the first Italian case of Charcot-Marie-Tooth 2CC harboring a novel frameshift variant in NEFH. J Peripher Nerv Syst 2021; 26:231-234. [PMID: 33987933 DOI: 10.1111/jns.12454] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 05/06/2021] [Accepted: 05/08/2021] [Indexed: 12/13/2022]
Abstract
Charcot-Marie-Tooth (CMT) diseases are a clinically and genetically heterogeneous group of disorders. Different variants in the neurofilament heavy chain (NEFH) gene have been described to cause the CMT2CC subtype. Here we report the first Italian patient affected by CMT2CC, harboring a novel variant in NEFH. In describing our patient, we also reviewed previously CMT2CC individuals, and suggested to consider NEFH variant if patients have an axonal sensory-motor neuropathy with a prominent proximal muscles involvement with early requirement of walking aids or wheelchair, remembering a motor neuron disorder.
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Affiliation(s)
- Francesco Aruta
- Department of Neuroscience, Reproductive and Odontostomatological Science, University of Naples "Federico II", Naples, Italy
| | - Daniele Severi
- Department of Neuroscience, Reproductive and Odontostomatological Science, University of Naples "Federico II", Naples, Italy
| | - Aniello Iovino
- Department of Neuroscience, Reproductive and Odontostomatological Science, University of Naples "Federico II", Naples, Italy
| | - Emanuele Spina
- Department of Neuroscience, Reproductive and Odontostomatological Science, University of Naples "Federico II", Naples, Italy
| | | | - Lucia Ruggiero
- Department of Neuroscience, Reproductive and Odontostomatological Science, University of Naples "Federico II", Naples, Italy
| | - Rosa Iodice
- Department of Neuroscience, Reproductive and Odontostomatological Science, University of Naples "Federico II", Naples, Italy
| | | | - Fiore Manganelli
- Department of Neuroscience, Reproductive and Odontostomatological Science, University of Naples "Federico II", Naples, Italy
| | - Stefano Tozza
- Department of Neuroscience, Reproductive and Odontostomatological Science, University of Naples "Federico II", Naples, Italy
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Hwang SH, Chang EH, Kwak G, Jeon H, Choi BO, Hong YB. Gait parameters as tools for analyzing phenotypic alterations of a mouse model of Charcot-Marie-Tooth disease. Anim Cells Syst (Seoul) 2021; 25:11-18. [PMID: 33717412 PMCID: PMC7935128 DOI: 10.1080/19768354.2021.1880967] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Charcot-Marie-Tooth disease (CMT), a genetically heterogeneous group of diseases in the peripheral nervous system, is characterized by progressive and symmetrical distal weakness resulting in gait abnormality. The necessity of the diagnostic and prognostic biomarkers has been raised for both basic research and clinical practice in CMT. Since biomarkers for animal study of CMT are limited, we evaluated the feasibility of gait parameters as tool for measuring disease phenotype of CMT mouse model. Using a Trembler-J (Tr-J) mouse, a CMT type 1 (CMT1) mouse model, we analyzed kinematic parameters such as angles of hip, knee and ankle (sagittal plane), and spatial parameters including step width and stride length (transverse plane). Regarding of kinematic parameters, Tr-J mice exhibited less plantarflexed ankle during the swing phase and more dorsiflexed ankle at the terminal stance compared to control mice. The range of motion in ankle angle of Tr-J mice was significantly greater than that of control mice. In spatial parameter, Tr-J mice exhibited wider step width compared to control mice. These results are similar to previously reported gait patterns of CMT1 patients. In comparison with other markers such as nerve conduction study and rotarod test, gait parameters dynamically reflected the disease progression of CMT1 mice. Therefore, these data imply that gait parameters can be used as useful tools to analyzed the disease phenotype and progression during preclinical study of peripheral neuropathy such as CMT.
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Affiliation(s)
- Sun Hee Hwang
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Eun Hyuk Chang
- Samsung Biomedical Research Institute, Samsung Advanced Institute of Technology, Samsung Electronics Co., Ltd., Seoul, Republic of Korea
| | - Geon Kwak
- Department of Health Sciences and Technology, SAIHST, Sungkyunkwan University, Seoul, Republic of Korea
| | - Hyeonjin Jeon
- Department of Biochemistry, College of Medicine, Dong-A University, Busan, Republic of Korea.,Department of Translational Biomedical Sciences, Graduate School of Dong-A University, Busan, Korea
| | - Byung-Ok Choi
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.,Department of Health Sciences and Technology, SAIHST, Sungkyunkwan University, Seoul, Republic of Korea
| | - Young Bin Hong
- Department of Biochemistry, College of Medicine, Dong-A University, Busan, Republic of Korea.,Department of Translational Biomedical Sciences, Graduate School of Dong-A University, Busan, Korea
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13
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Yuan RY, Ye ZL, Zhang XR, Xu LQ, He J. Evaluation of SORD mutations as a novel cause of Charcot-Marie-Tooth disease. Ann Clin Transl Neurol 2020; 8:266-270. [PMID: 33314640 PMCID: PMC7818235 DOI: 10.1002/acn3.51268] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 11/03/2020] [Accepted: 11/03/2020] [Indexed: 01/06/2023] Open
Abstract
Biallelic mutations in the sorbitol dehydrogenase (SORD) encoding gene were recently identified as a common genetic cause in autosomal-recessive CMT patients. Here, we investigated the clinical, genetic, and electrophysiological characteristics of three CMT patients with biallelic SORD mutations from a Chinese cohort. Two patients harbored c.757delG (p.A253Qfs*27) homozygous mutations, and one patient carried both c.757delG (p.A253Qfs*27) and c.625C>T (p.R209X) compound heterozygous mutations. Interestingly, the two patients homozygous for the c.757delG mutation exhibited positive responses for pinprick test. In conclusion, we confirmed SORD mutations as causative for CMT and further expanded the mutational and phenotypic spectrum of SORD-related CMT.
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Affiliation(s)
- Ru-Ying Yuan
- Department of Neurology and Institute of Neurology, First Affiliated Hospital, Institute of Neuroscience, Fujian Key Laboratory of Molecular Neurology, Fujian Medical University, Fuzhou, 350005, China
| | - Zi-Ling Ye
- Department of Neurology and Institute of Neurology, First Affiliated Hospital, Institute of Neuroscience, Fujian Key Laboratory of Molecular Neurology, Fujian Medical University, Fuzhou, 350005, China
| | - Xiao-Rong Zhang
- Department of Neurology and Institute of Neurology, First Affiliated Hospital, Institute of Neuroscience, Fujian Key Laboratory of Molecular Neurology, Fujian Medical University, Fuzhou, 350005, China
| | - Liu-Qing Xu
- Department of Neurology and Institute of Neurology, First Affiliated Hospital, Institute of Neuroscience, Fujian Key Laboratory of Molecular Neurology, Fujian Medical University, Fuzhou, 350005, China
| | - Jin He
- Department of Neurology and Institute of Neurology, First Affiliated Hospital, Institute of Neuroscience, Fujian Key Laboratory of Molecular Neurology, Fujian Medical University, Fuzhou, 350005, China
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14
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Mendoza-Ferreira N, Karakaya M, Cengiz N, Beijer D, Brigatti KW, Gonzaga-Jauregui C, Fuhrmann N, Hölker I, Thelen MP, Zetzsche S, Rombo R, Puffenberger EG, De Jonghe P, Deconinck T, Zuchner S, Strauss KA, Carson V, Schrank B, Wunderlich G, Baets J, Wirth B. De Novo and Inherited Variants in GBF1 are Associated with Axonal Neuropathy Caused by Golgi Fragmentation. Am J Hum Genet 2020; 107:763-777. [PMID: 32937143 PMCID: PMC7491385 DOI: 10.1016/j.ajhg.2020.08.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 08/19/2020] [Indexed: 01/18/2023] Open
Abstract
Distal hereditary motor neuropathies (HMNs) and axonal Charcot-Marie-Tooth neuropathy (CMT2) are clinically and genetically heterogeneous diseases characterized primarily by motor neuron degeneration and distal weakness. The genetic cause for about half of the individuals affected by HMN/CMT2 remains unknown. Here, we report the identification of pathogenic variants in GBF1 (Golgi brefeldin A-resistant guanine nucleotide exchange factor 1) in four unrelated families with individuals affected by sporadic or dominant HMN/CMT2. Genomic sequencing analyses in seven affected individuals uncovered four distinct heterozygous GBF1 variants, two of which occurred de novo. Other known HMN/CMT2-implicated genes were excluded. Affected individuals show HMN/CMT2 with slowly progressive distal muscle weakness and musculoskeletal deformities. Electrophysiological studies confirmed axonal damage with chronic neurogenic changes. Three individuals had additional distal sensory loss. GBF1 encodes a guanine-nucleotide exchange factor that facilitates the activation of members of the ARF (ADP-ribosylation factor) family of small GTPases. GBF1 is mainly involved in the formation of coatomer protein complex (COPI) vesicles, maintenance and function of the Golgi apparatus, and mitochondria migration and positioning. We demonstrate that GBF1 is present in mouse spinal cord and muscle tissues and is particularly abundant in neuropathologically relevant sites, such as the motor neuron and the growth cone. Consistent with the described role of GBF1 in Golgi function and maintenance, we observed marked increase in Golgi fragmentation in primary fibroblasts derived from all affected individuals in this study. Our results not only reinforce the existing link between Golgi fragmentation and neurodegeneration but also demonstrate that pathogenic variants in GBF1 are associated with HMN/CMT2.
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15
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A novel missense pathogenic variant in NEFH causing rare Charcot-Marie-Tooth neuropathy type 2CC. Neurol Sci 2020; 42:757-763. [PMID: 32780247 DOI: 10.1007/s10072-020-04595-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 07/11/2020] [Indexed: 10/23/2022]
Abstract
The purpose of this research is to explore the underlying genes of Charcot-Marie-Tooth (CMT). Technologies such as electrophysiological testing and gene sequencing have been applied. We identified a novel variant NEFH c.2215C>T(p.P739S)(HGNC:7737) in a heterozygous state, which was considered to be pathogenic for CMT2CC(OMIM:616924).The proband and his brothers presented with muscle atrophy of hand and calf and moderately decreased conduction velocities. By whole exome sequencing analysis, we found the novel missense pathogenic variant in the proband, his brother and mother. This report broadened current knowledge about intermediate CMT and the phenotypic spectrum of defects associated with NEFH. In addition, the proband carried other five variants {HSPD1c.695C>A (p.S232X), FLNCc.1073A>G (p.N358S), GUSBc.323C>A (p.P108Q), ACY1 c.1063-1G>A and APTX c.484-2A>T}, which have not been reported until now. The NEFH c.2215C>T (p.P739S) give us a new understanding of CMT, which might provide new therapeutic targets in the future.
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16
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Thenmozhi R, Lee JS, Park NY, Choi BO, Hong YB. Gene Therapy Options as New Treatment for Inherited Peripheral Neuropathy. Exp Neurobiol 2020; 29:177-188. [PMID: 32624504 PMCID: PMC7344374 DOI: 10.5607/en20004] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Revised: 04/21/2020] [Accepted: 05/11/2020] [Indexed: 02/06/2023] Open
Abstract
Inherited peripheral neuropathy (IPN) is caused by heterogeneous genetic mutations in more than 100 genes. So far, several treatment options for IPN have been developed and clinically evaluated using small molecules. However, gene therapy-based therapeutic strategies have not been aggressively investigated, likely due to the complexities of inheritance in IPN. Indeed, because the majority of the causative mutations of IPN lead to gain-of-function rather than loss-of-function, developing a therapeutic strategy is more difficult, especially considering gene therapy for genetic diseases began with the simple idea of replacing a defective gene with a functional copy. Recent advances in gene manipulation technology have brought novel approaches to gene therapy and its clinical application for IPN treatment. For example, in addition to the classically used gene replacement for mutant genes in recessively inherited IPN, other techniques including gene addition to modify the disease phenotype, modulations of target gene expression, and techniques to edit mutant genes have been developed and evaluated as potent therapeutic strategies for dominantly inherited IPN. In this review, the current status of gene therapy for IPN and future perspectives will be discussed.
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Affiliation(s)
| | - Ji-Su Lee
- Stem Cell & Regenerative Medicne Institute, Samsung Medical Center, Seoul 06351, Korea.,Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, Korea
| | - Na Young Park
- Department of Biochemistry, College of Medicine, Dong-A University, Busan 49201, Korea
| | - Byung-Ok Choi
- Stem Cell & Regenerative Medicne Institute, Samsung Medical Center, Seoul 06351, Korea.,Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, Korea.,Department of Health Sciences and Technology, SAIHST, Sungkyunkwan University, Seoul 06351, Korea
| | - Young Bin Hong
- Department of Biochemistry, College of Medicine, Dong-A University, Busan 49201, Korea
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Zhao X, Jiang MM, Yan YZ, Liu L, Xie YZ, Li XB, Hu ZM, Zi XH, Xia K, Tang BS, Zhang RX. Screening for SH3TC2, PMP2, and BSCL2 Variants in a Cohort of Chinese Patients with Charcot-Marie-Tooth. Chin Med J (Engl) 2018; 131:151-155. [PMID: 29336362 PMCID: PMC5776844 DOI: 10.4103/0366-6999.222331] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND SH3TC2, PMP2, and BSCL2 genes are related to autosomal recessive (AR) Charcot-Marie-Tooth (CMT) disease type 1, autosomal dominant (AD)-CMT1, and AD-CMT2, respectively. Pathogenic variants in these three genes were not well documented in Chinese CMT patients. Therefore, this study aims to detect SH3TC2, PMP2, and BSCL2 pathogenic variants in a cohort of 315 unrelated Chinese CMT families. METHODS A total of 315 probands from 315 unrelated Chinese CMT families were recruited from the Department of Neurology of Third Xiangya Hospital and Xiangya Hospital. We screened for SH3TC2 pathogenic variants in 84 AR or sporadic CMT probands, PMP2 pathogenic variants in 39 AD or sporadic CMT1 probands, and BSCL2 pathogenic variants in 50 AD or sporadic CMT2 probands, using polymerase chain reaction and Sanger sequencing. All these patients were out of 315 unrelated Chinese CMT families and genetically undiagnosed after exclusion of pathogenic variants of PMP22, MFN2, MPZ, GJB1, GDAP1, HSPB1, HSPB8, EGR2, NEFL, and RAB7. Candidate variants were analyzed based on the standards and guidelines of American College of Medical Genetics and Genomics (ACMG). Clinical features were reevaluated. RESULTS We identified three novel heterozygous variants such as p.L95V (c.283C>G), p.L1048P (c.3143T>C), and p.V1105M (c.3313G>A) of SH3TC2 gene and no pathogenic variants of PMP2 and BSCL2 genes. Although evaluation in silico and screening in the healthy control revealed that the three SH3TC2 variants were likely pathogenic, no second allele variants were discovered. According to the standards and guidelines of ACMG, the heterozygous SH3TC2 variants such as p.L95V, p.L1048P, and p.V1105M were considered to be of uncertain significance. CONCLUSIONS SH3TC2, PMP2, and BSCL2 pathogenic variants might be rare in Chinese CMT patients. Further studies to confirm our findings are needed.
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Affiliation(s)
- Xin Zhao
- Department of Neurology, The Third Xiangya Hospital of Central South University, Changsha, Hunan 410006, China
| | - Ming-Ming Jiang
- Department of Neurology, The Third Xiangya Hospital of Central South University, Changsha, Hunan 410006, China
| | - Yi-Zhou Yan
- Department of Neurology, The Third Xiangya Hospital of Central South University, Changsha, Hunan 410006, China
| | - Lei Liu
- Health Management Center, The Third Xiangya Hospital of Central South University, Changsha, Hunan 410006, China
| | - Yong-Zhi Xie
- Department of Neurology, The Third Xiangya Hospital of Central South University, Changsha, Hunan 410006, China
| | - Xiao-Bo Li
- Department of Neurology, The Third Xiangya Hospital of Central South University, Changsha, Hunan 410006, China
| | - Zheng-Mao Hu
- State Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan 410006, China
| | - Xiao-Hong Zi
- Department of Neurology, The Third Xiangya Hospital of Central South University, Changsha, Hunan 410006, China
| | - Kun Xia
- State Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan 410006, China
| | - Bei-Sha Tang
- Department of Neurology, The Xiangya Hospital of Central South University, Changsha, Hunan 410006, China
| | - Ru-Xu Zhang
- Department of Neurology, The Third Xiangya Hospital of Central South University, Changsha, Hunan 410006, China
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18
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Abstract
PURPOSE OF REVIEW Genetic polyneuropathies are rare and clinically heterogeneous. This article provides an overview of the clinical features, neurologic and electrodiagnostic findings, and management strategies for Charcot-Marie-Tooth disease and other genetic polyneuropathies as well as an algorithm for genetic testing. RECENT FINDINGS In the past 10 years, many of the mutations causing genetic polyneuropathies have been identified. International collaborations have led to the development of consortiums that are undertaking careful genotype-phenotype correlations to facilitate the development of targeted therapies and validation of outcome measures for future clinical trials. Clinical trials are currently under way for some genetic polyneuropathies. SUMMARY Readers are provided a framework to recognize common presentations of various genetic polyneuropathies and a rationale for current diagnostic testing and management strategies in genetic polyneuropathies.
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19
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Nam DE, Jung SC, Yoo DH, Choi SS, Seo SY, Kim GH, Kim SJ, Nam SH, Choi BO, Chung KW. Axonal Charcot-Marie-Tooth neuropathy concurrent with distal and proximal weakness by translational elongation of the 3' UTR in NEFH. J Peripher Nerv Syst 2018; 22:200-207. [PMID: 28544463 DOI: 10.1111/jns.12223] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 05/18/2017] [Accepted: 05/20/2017] [Indexed: 11/27/2022]
Abstract
Mutations in the NEFH gene encoding the heavy neurofilament protein are usually associated with neuronal damage and susceptibility to amyotrophic lateral sclerosis (ALS). Recently, frameshift variants in NEFH (p.Asp1004Glnfs*58 and p.Pro1008Alafs*56) have been reported to be the underlying cause of axonal Charcot-Marie-Tooth disease type 2CC (CMT2CC). The frameshift mutation resulted in a stop loss and translation of a cryptic amyloidogenic element (CAE) encoded by the 3' untranslated region (UTR). This study also identified a de novo c.3015_3027dup frameshift mutation predicting p.Lys1010Glnfs*57 in NEFH from a CMT2 family with an atypical clinical symptom of prominent proximal weakness. This mutation is located near the previously reported frameshift mutations, suggesting a mutational hotspot. Lower limb magnetic resonance imaging (MRI) revealed marked hyperintense signal changes in the thigh muscles compared with those in the calf muscles. Therefore, this study suggests that the stop loss and translational elongations by the 3' UTR of the NEFH mutations may be a relatively frequent genetic cause of axonal peripheral neuropathy with the specific characteristics of proximal dominant weakness.
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Affiliation(s)
- Da Eun Nam
- Department of Biological Sciences, Kongju National University, Gongju, Korea
| | - Sung-Chul Jung
- Department of Biochemistry, Ewha Womans University School of Medicine, Seoul, Korea
| | - Da Hye Yoo
- Department of Biological Sciences, Kongju National University, Gongju, Korea
| | - Sun Seong Choi
- Department of Biological Sciences, Kongju National University, Gongju, Korea
| | - Sung-Yum Seo
- Department of Biological Sciences, Kongju National University, Gongju, Korea
| | - Gwang Hoon Kim
- Department of Biological Sciences, Kongju National University, Gongju, Korea
| | - Song Ja Kim
- Department of Biological Sciences, Kongju National University, Gongju, Korea
| | - Soo Hyun Nam
- Department of Biological Sciences, Kongju National University, Gongju, Korea.,Department of Neurology, and Stem Cell & Regenerative Medicine Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Byung-Ok Choi
- Department of Neurology, and Stem Cell & Regenerative Medicine Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.,Department of Health Sciences and Technology, Samsung Advanced Institute for Health Science & Technology, Sungkyunkwan University, Seoul, Korea
| | - Ki Wha Chung
- Department of Biological Sciences, Kongju National University, Gongju, Korea
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20
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Nam SH, Kanwal S, Nam DE, Lee MH, Kang TH, Jung SC, Choi BO, Chung KW. Association of miR-149 polymorphism with onset age and severity in Charcot-Marie-Tooth disease type 1A. Neuromuscul Disord 2018; 28:502-507. [PMID: 29729827 DOI: 10.1016/j.nmd.2018.04.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 03/28/2018] [Accepted: 04/03/2018] [Indexed: 02/03/2023]
Abstract
Charcot-Marie-Tooth disease type 1A (CMT1A) is caused by 1.5-fold increased dosage of the PMP22; however, onset age and severity vary considerably among patients. The exact reason behind these phenotypic heterogeneities has rarely been discovered yet. Because miRNAs are the key regulators of gene expression, we speculated that variants of miRNAs might be the genetic modifiers for CMT1A. This study noticed a common single nucleotide polymorphism (n.86T > C, rs2292832) in the miR-149 which was predicted to target several CMT causing genes including PMP22. The rs2292832 was located near the 3' end of the precursor microRNA of the miR-149. We performed an association study between the rs2292832 polymorphism and clinical phenotypes of CMT1A in subjects consisting of 176 unrelated Korean CMT1A patients and 176 controls. From this study, we observed that rs2292832 was closely associated to the onset age and severity of CMT1A. Particularly, the TC and CC genotypes were significantly associated with late onset and mild symptom. Therefore, we suggest that the rs2292832 variant in the miR-149 is a potential candidate as a genetic modifier which affects the phenotypic heterogeneity of CMT1A. This study may provide the first evidence that polymorphism in the miR gene is associated with the CMT1A phenotype.
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Affiliation(s)
- Soo Hyun Nam
- Department of Biological Sciences, Kongju National University, Gongju, Republic of Korea; Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Sumaira Kanwal
- Department of Biosciences, COMSATS Institute of Information Technology Sahiwal Campus, Pakistan
| | - Da Eun Nam
- Department of Biological Sciences, Kongju National University, Gongju, Republic of Korea
| | - Min Hee Lee
- Department of Biological Sciences, Kongju National University, Gongju, Republic of Korea
| | - Tae Hoon Kang
- Department of Biological Sciences, Kongju National University, Gongju, Republic of Korea
| | - Sung-Chul Jung
- Department of Biochemistry, Ewha Womans University School of Medicine, Seoul, Republic of Korea
| | - Byung-Ok Choi
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea; Department of Health Sciences and Technology, Samsung Advanced Institute for Health Science & Tech, Sungkyunkwan University, Seoul, Republic of Korea.
| | - Ki Wha Chung
- Department of Biological Sciences, Kongju National University, Gongju, Republic of Korea.
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21
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Khadilkar SV, Yadav RS, Patel BA. X-Linked Charcot–Marie–Tooth Disease. Neuromuscul Disord 2018. [DOI: 10.1007/978-981-10-5361-0_39] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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22
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Liao YC, Tsai PC, Lin TS, Hsiao CT, Chao NC, Lin KP, Lee YC. Clinical and Molecular Characterization of PMP22 point mutations in Taiwanese patients with Inherited Neuropathy. Sci Rep 2017; 7:15363. [PMID: 29127354 PMCID: PMC5681590 DOI: 10.1038/s41598-017-14771-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 10/13/2017] [Indexed: 01/13/2023] Open
Abstract
Point mutations in the peripheral myelin protein 22 (PMP22) gene have been identified to cause demyelinating Charcot-Marie-Tooth disease (CMT) and hereditary neuropathy with liability to pressure palsy (HNPP). To investigate the mutation spectrum of PMP22 in Han-Chinese population residing in Taiwan, 53 patients with molecularly unassigned demyelinating CMT and 52 patients with HNPP-like neuropathy of unknown genetic causes were screened for PMP22 mutations by Sanger sequencing. Three point mutations were identified in four patients with demyelinating CMT, including c.256 C > T (p.Q86X) in two, and c.310delA (p.I104FfsX7) and c.319 + 1G > A in one each. One PMP22 missense mutation, c.124 T > C (p.C42R), was identified in a patient with HNPP-like neuropathy. The clinical presentations of these mutations vary from mild HNPP-like syndrome to severe infantile-onset demyelinating CMT. In vitro analyses revealed that both PMP22 p.Q86X and p.I104FfsX7 mutations result in truncated PMP22 proteins that are almost totally retained within cytosol, whereas the p.C42R mutation partially impairs cell membrane localization of PMP22 protein. In conclusion, PMP22 point mutations account for 7.5% and 1.9% of demyelinating CMT and HNPP patients with unknown genetic causes, respectively. This study delineates the clinical and molecular features of PMP22 point mutations in Taiwan, and emphasizes their roles in demyelinating CMT or HNPP-like neuropathy.
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Affiliation(s)
- Yi-Chu Liao
- Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC. .,Department of Neurology, National Yang-Ming University School of Medicine, Taipei, Taiwan, ROC.
| | - Pei-Chien Tsai
- Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC.,Department of Neurology, National Yang-Ming University School of Medicine, Taipei, Taiwan, ROC.,Brain Research Center, National Yang-Ming University, Taipei, Taiwan, ROC
| | - Thy-Sheng Lin
- Department of Neurology, College of Medicine, National Cheng Kung University, Tainan, Taiwan, ROC.,Department of Neurology, National Cheng Kung University Hospital, Tainan, Taiwan, ROC
| | - Cheng-Tsung Hsiao
- Department of Neurology, National Yang-Ming University School of Medicine, Taipei, Taiwan, ROC.,Division of Neurology, Department of Internal Medicine, Taipei Veterans General Hospital Taoyuan Branch, Taoyuan, Taiwan, ROC.,Graduate Institute of Physiology, College of Medicine, National Taiwan University, Taipei, Taiwan, ROC
| | - Nai-Chen Chao
- Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
| | - Kon-Ping Lin
- Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC.,Department of Neurology, National Yang-Ming University School of Medicine, Taipei, Taiwan, ROC
| | - Yi-Chung Lee
- Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC.,Department of Neurology, National Yang-Ming University School of Medicine, Taipei, Taiwan, ROC.,Brain Research Center, National Yang-Ming University, Taipei, Taiwan, ROC
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23
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Haidar M, Timmerman V. Autophagy as an Emerging Common Pathomechanism in Inherited Peripheral Neuropathies. Front Mol Neurosci 2017; 10:143. [PMID: 28553203 PMCID: PMC5425483 DOI: 10.3389/fnmol.2017.00143] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 04/26/2017] [Indexed: 12/16/2022] Open
Abstract
The inherited peripheral neuropathies (IPNs) comprise a growing list of genetically heterogeneous diseases. With mutations in more than 80 genes being reported to cause IPNs, a wide spectrum of functional consequences is expected to follow this genotypic diversity. Hence, the search for a common pathomechanism among the different phenotypes has become the holy grail of functional research into IPNs. During the last decade, studies on several affected genes have shown a direct and/or indirect correlation with autophagy. Autophagy, a cellular homeostatic process, is required for the removal of cell aggregates, long-lived proteins and dead organelles from the cell in double-membraned vesicles destined for the lysosomes. As an evolutionarily highly conserved process, autophagy is essential for the survival and proper functioning of the cell. Recently, neuronal cells have been shown to be particularly vulnerable to disruption of the autophagic pathway. Furthermore, autophagy has been shown to be affected in various common neurodegenerative diseases of both the central and the peripheral nervous system including Alzheimer's, Parkinson's, and Huntington's diseases. In this review we provide an overview of the genes involved in hereditary neuropathies which are linked to autophagy and we propose the disruption of the autophagic flux as an emerging common pathomechanism. We also shed light on the different steps of the autophagy pathway linked to these genes. Finally, we review the concept of autophagy being a therapeutic target in IPNs, and the possibilities and challenges of this pathway-specific targeting.
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Affiliation(s)
- Mansour Haidar
- Peripheral Neuropathy Research Group, Institute Born Bunge, University of AntwerpAntwerpen, Belgium
| | - Vincent Timmerman
- Peripheral Neuropathy Research Group, Institute Born Bunge, University of AntwerpAntwerpen, Belgium
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24
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Gagic M, Markovic MK, Kecmanovic M, Keckarevic D, Mladenovic J, Dackovic J, Milic-Rasic V, Romac S. Analysis of PMP22 duplication and deletion using a panel of six dinucleotide tandem repeats. Clin Chem Lab Med 2017; 54:773-80. [PMID: 26479344 DOI: 10.1515/cclm-2015-0602] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 09/10/2015] [Indexed: 11/15/2022]
Abstract
BACKGROUND Charcot-Marie-Tooth type 1A (CMT1A) is the most common type of hereditary motor and sensory neuropathies (HMSN), caused by the duplication of the 17p11.2 region that includes the PMP22 gene. Reciprocal deletion of the same region is the main cause of hereditary neuropathy with liability to pressure palsies (HNPP). CMT1A accounts for approximately 50% of HMSN patients. Diagnostics of CMT1A and HNPP are based on quantitative analysis of the affected region or RFLP detection of breakage points. The aim of this study was to improve the sensitivity and efficiency of CMT1A and HNPP genetic diagnostics by introducing analysis of six STR markers (D17S261-D17S122-D17S839-D17S1358-D17S955-D17S921) spanning the duplicated region. METHODS Forty-six CMT1A and seven HNPP patients, all genetically diagnosed by RFLP analysis, were tested for duplication or deletion using six STR markers. RESULTS In all CMT1A and HNPP patients, microsatellite analysis comprising six STR markers confirmed the existence of a duplication or deletion. In 89% (41/46) CMT1A patients the confirmation was based on detecting three alleles on at least one locus. In the remaining 11% (5) CMT1A patients, duplication was also confirmed based on two peaks with clear dosage difference for at least two different markers. All HNPP patients (7/7) displayed only one allele for each analyzed locus. CONCLUSIONS Microsatellite analysis using six selected STR loci showed a high level of sensitivity and specificity for genetic diagnostics of CMT1A and HNPP. The results here strongly suggest STR marker analysis as a method of choice in PMP22 duplication/deletion testing.
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Lupo V, Aguado C, Knecht E, Espinós C. Chaperonopathies: Spotlight on Hereditary Motor Neuropathies. Front Mol Biosci 2016; 3:81. [PMID: 28018906 PMCID: PMC5155517 DOI: 10.3389/fmolb.2016.00081] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 11/29/2016] [Indexed: 12/18/2022] Open
Abstract
Distal hereditary motor neuropathies (dHMN) are a group of rare hereditary neuromuscular disorders characterized by an atrophy that affects peroneal muscles in the absence of sensory symptoms. To date, 23 genes are thought to be responsible for dHMN, four of which encode chaperones: DNAJB2, which encodes a member of the HSP40/DNAJ co-chaperone family; and HSPB1, HSPB3, and HSPB8, encoding three members of the small heat shock protein family. While around 30 different mutations in HSPB1 have been identified, the remaining three genes are altered in many fewer cases. Indeed, a mutation of HSPB3 has only been described in one case, whereas a few cases have been reported carrying mutations in DNAJB2 and HSPB8, most of them caused by a founder c.352+1G>A mutation in DNAJB2 and by mutations affecting the K141 residue in the HSPB8 chaperone. Hence, their rare occurrence makes it difficult to understand the pathological mechanisms driven by such mutations in this neuropathy. Chaperones can assemble into multi-chaperone complexes that form an integrated chaperone network within the cell. Such complexes fulfill relevant roles in a variety of processes, such as the correct folding of newly synthesized proteins, in which chaperones escort them to precise cellular locations, and as a response to protein misfolding, which includes the degradation of proteins that fail to refold properly. Despite this range of functions, mutations in some of these chaperones lead to diseases with a similar clinical profile, suggesting common pathways. This review provides an overview of the genetics of those dHMNs that share a common disease mechanism and that are caused by mutations in four genes encoding chaperones: DNAJB2, HSPB1, HSPB3, and HSPB8.
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Affiliation(s)
- Vincenzo Lupo
- Molecular Basis of Human Diseases Program, Centro de Investigación Príncipe FelipeValencia, Spain; INCLIVA & IIS La Fe Rare Diseases Joint UnitsValencia, Spain
| | - Carmen Aguado
- Molecular Basis of Human Diseases Program, Centro de Investigación Príncipe FelipeValencia, Spain; INCLIVA & IIS La Fe Rare Diseases Joint UnitsValencia, Spain; Centro de Investigación Biomédica en RedValencia, Spain
| | - Erwin Knecht
- Molecular Basis of Human Diseases Program, Centro de Investigación Príncipe FelipeValencia, Spain; INCLIVA & IIS La Fe Rare Diseases Joint UnitsValencia, Spain; Centro de Investigación Biomédica en RedValencia, Spain
| | - Carmen Espinós
- Molecular Basis of Human Diseases Program, Centro de Investigación Príncipe FelipeValencia, Spain; INCLIVA & IIS La Fe Rare Diseases Joint UnitsValencia, Spain
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Hwang SH, Kim EJ, Hong YB, Joo J, Kim SM, Nam SH, Hong HD, Kim SH, Oh K, Lim JG, Cho JH, Chung KW, Choi BO. Distal hereditary motor neuropathy type 7B with Dynactin 1 mutation. Mol Med Rep 2016; 14:3362-8. [PMID: 27573046 DOI: 10.3892/mmr.2016.5664] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2015] [Accepted: 07/13/2016] [Indexed: 11/06/2022] Open
Abstract
Mutations in the Dynactin 1 (DCTN1) gene have been demonstrated to result in various neurodegenerative diseases, including distal hereditary motor neuropathy type 7B (dHMN7B), Perry syndrome, amyotrophic lateral sclerosis and amyotrophic lateral sclerosis‑frontotemporal dementia. However, since the first dHMN7B patient with a DCTN1 mutation was described in 2003, to the best of our knowledge no further cases have been reported. In the present study, the DCTN1 p.G59S mutation was identified in two unrelated families from a total of 24 Korean families with dHMN, by whole exome sequencing. Codon 59 appears to be the mutational hot spot in the DCTN1 gene, as all described dHMN7B patients to date have harbored an identical p.G59S mutation. The families of the present study with the DCTN1 mutation had a milder disease with a later onset compared with the previously described patients. No affected family members exhibited facial muscle weakness or bulbar involvement. One family member demonstrated vocal cord palsy as the initial sign of disease; however, in the other family hand muscle weakness was the first major symptom. No affected patients demonstrated sensory loss or upper motor neuron involvements. Although this is only the second report of dHMN7B resulting from a DCTN1 mutation, the frequency of the DCTN1 mutation was not low in the Korean population examined, and clinical heterogeneities were observed in patients with the DCTN1 mutation. Therefore, it may be beneficial to screen all dHMN patients for the DCTN1 mutation.
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Affiliation(s)
- Sun Hee Hwang
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, Republic of Korea
| | - Eun Ja Kim
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, Republic of Korea
| | - Young Bin Hong
- Stem Cell & Regenerative Medicine Center, Samsung Medical Center, Seoul 06351, Republic of Korea
| | - Jaesoon Joo
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, Republic of Korea
| | - Sung Min Kim
- Department of Biological Sciences, Kongju National University, Gongju, South Chungcheong 32588, Republic of Korea
| | - Soo Hyun Nam
- Department of Biological Sciences, Kongju National University, Gongju, South Chungcheong 32588, Republic of Korea
| | - Hyun Dae Hong
- Department of Biological Sciences, Kongju National University, Gongju, South Chungcheong 32588, Republic of Korea
| | - Seung Hyun Kim
- Department of Neurology, Hanyang University College of Medicine, Seoul 04763, Republic of Korea
| | - Kiwook Oh
- Department of Neurology, Hanyang University College of Medicine, Seoul 04763, Republic of Korea
| | - Jeong-Geun Lim
- Department of Neurology, Keimyung University College of Medicine, Daegu 42403, Republic of Korea
| | - Jeong Hee Cho
- Department of Neurology, National Health Insurance Corporation Ilsan Hospital, Goyang, Gyeonggi 10444, Republic of Korea
| | - Ki Wha Chung
- Department of Biological Sciences, Kongju National University, Gongju, South Chungcheong 32588, Republic of Korea
| | - Byung-Ok Choi
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, Republic of Korea
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Wang Y, Yin F. A Review of X-linked Charcot-Marie-Tooth Disease. J Child Neurol 2016; 31:761-72. [PMID: 26385972 DOI: 10.1177/0883073815604227] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 08/06/2015] [Indexed: 01/25/2023]
Abstract
X-linked Charcot-Marie-Tooth disease (CMTX) is the second common genetic variant of CMT. CMTX type 1 causes 90% of CMTX. The most important clinical features of CMTX are similar with other types of CMT; however, a few patients get the central nervous system involved with or without white matter lesions; males are more severely and earlier affected than females. In this review, the authors focus on the origin and classification of CMTX, the central nervous system manifestations of CMTX1, the possible mechanism by which GJB1 mutations cause CMT1X, and the emerging therapeutic strategies for CMTX. Moreover, several cases are presented to illustrate the central nervous system manifestations.
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Affiliation(s)
- Ying Wang
- Department of Pediatrics, Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Fei Yin
- Department of Pediatrics, Xiangya Hospital of Central South University, Changsha, Hunan, China Hunan Intellectual and Developmental Disabilities Research Center, Hunan, China
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Neupauerová J, Grečmalová D, Seeman P, Laššuthová P. Massively Parallel Sequencing Detected a Mutation in the MFN2 Gene Missed by Sanger Sequencing Due to a Primer Mismatch on an SNP Site. Ann Hum Genet 2016; 80:182-6. [PMID: 26916081 DOI: 10.1111/ahg.12151] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 12/22/2015] [Accepted: 01/05/2016] [Indexed: 11/25/2022]
Abstract
We describe a patient with early onset severe axonal Charcot-Marie-Tooth disease (CMT2) with dominant inheritance, in whom Sanger sequencing failed to detect a mutation in the mitofusin 2 (MFN2) gene because of a single nucleotide polymorphism (rs2236057) under the PCR primer sequence. The severe early onset phenotype and the family history with severely affected mother (died after delivery) was very suggestive of CMT2A and this suspicion was finally confirmed by a MFN2 mutation. The mutation p.His361Tyr was later detected in the patient by massively parallel sequencing with a gene panel for hereditary neuropathies. According to this information, new primers for amplification and sequencing were designed which bind away from the polymorphic sites of the patient's DNA. Sanger sequencing with these new primers then confirmed the heterozygous mutation in the MFN2 gene in this patient. This case report shows that massively parallel sequencing may in some rare cases be more sensitive than Sanger sequencing and highlights the importance of accurate primer design which requires special attention.
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Affiliation(s)
- Jana Neupauerová
- DNA Laboratory, Department of Paediatric Neurology, 2nd Faculty of Medicine, Charles University in Prague and University Hospital Motol, Prague, Czech Republic
| | - Dagmar Grečmalová
- Department of Medical Genetics, University Hospital in Ostrava, Czech Republic
| | - Pavel Seeman
- DNA Laboratory, Department of Paediatric Neurology, 2nd Faculty of Medicine, Charles University in Prague and University Hospital Motol, Prague, Czech Republic
| | - Petra Laššuthová
- DNA Laboratory, Department of Paediatric Neurology, 2nd Faculty of Medicine, Charles University in Prague and University Hospital Motol, Prague, Czech Republic
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Albulym OM, Kennerson ML, Harms MB, Drew AP, Siddell AH, Auer-Grumbach M, Pestronk A, Connolly A, Baloh RH, Zuchner S, Reddel SW, Nicholson GA. MORC2 mutations cause axonal Charcot-Marie-Tooth disease with pyramidal signs. Ann Neurol 2016; 79:419-27. [PMID: 26659848 DOI: 10.1002/ana.24575] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Revised: 12/02/2015] [Accepted: 12/04/2015] [Indexed: 01/14/2023]
Abstract
OBJECTIVE To use linkage analysis and whole exome sequencing to identify the genetic mutation in a multigenerational Australian family with Charcot-Marie-Tooth disease type 2 (CMT2) and pyramidal signs. METHODS Genome-wide linkage analysis was performed to map the locus. Whole exome sequencing was undertaken on selected individuals (3 affected, 1 normal), and segregation analysis and mutation screening were carried out using high-resolution melt analysis. The GEM.app database was queried to identify additional families with mutations. RESULTS Significant linkage (2-point LOD score ≥ +3) and haplotype analysis mapped a new locus for CMT2 and pyramidal signs to a 6.6Mb interval on chromosome 22q12.1-q12.3. Whole exome sequencing identified a novel mutation (p.R252W) in the microrchidia CW-type zinc finger 2 (MORC2) gene mapping within the linkage region. The mutation fully segregated with the disease phenotype in the family. Screening additional families and querying unsolved CMT2 exomes, we identified the p.R252W mutation in 2 unrelated early onset CMT2 families and a second mutation p.E236G in 2 unrelated CMT2 families. Both the mutations occurred at highly conserved amino acid residues and were absent in the normal population. INTERPRETATION We have identified a new locus in which MORC2 mutations are the likely pathogenic cause of CMT2 and pyramidal signs in these families. MORC2 encodes the human CW-type zinc finger 2 protein, which is a chromatin modifier involved in the regulation of DNA repair as well as gene transcription.
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Affiliation(s)
- Obaid M Albulym
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Concord, NSW, Australia.,Sydney Medical School, University of Sydney, Sydney, NSW, Australia
| | - Marina L Kennerson
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Concord, NSW, Australia.,Sydney Medical School, University of Sydney, Sydney, NSW, Australia.,Molecular Medicine Laboratory, Concord Hospital, Concord, NSW, Australia
| | - Matthew B Harms
- Department of Neurology, Washington University School of Medicine, St Louis, MO
| | - Alexander P Drew
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Concord, NSW, Australia.,Sydney Medical School, University of Sydney, Sydney, NSW, Australia
| | - Anna H Siddell
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Concord, NSW, Australia.,Sydney Medical School, University of Sydney, Sydney, NSW, Australia
| | | | - Alan Pestronk
- Department of Neurology, Washington University School of Medicine, St Louis, MO
| | - Anne Connolly
- Department of Neurology, Washington University School of Medicine, St Louis, MO
| | - Robert H Baloh
- Department of Neurology, Cedars Sinai Medical Center, Los Angeles, CA
| | - Stephan Zuchner
- Dr John T. MacDonald Department of Human Genetics and John P. Hussman Institute for Human Genomics, University of Miami, Miami, FL
| | - Stephen W Reddel
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Concord, NSW, Australia.,Sydney Medical School, University of Sydney, Sydney, NSW, Australia.,Molecular Medicine Laboratory, Concord Hospital, Concord, NSW, Australia
| | - Garth A Nicholson
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Concord, NSW, Australia.,Sydney Medical School, University of Sydney, Sydney, NSW, Australia.,Molecular Medicine Laboratory, Concord Hospital, Concord, NSW, Australia
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30
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Demyelinating CMT–what’s known, what’s new and what’s in store? Neurosci Lett 2015; 596:14-26. [DOI: 10.1016/j.neulet.2015.01.059] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Accepted: 01/23/2015] [Indexed: 02/06/2023]
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31
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Mathis S, Magy L, Vallat JM. Therapeutic options in Charcot–Marie–Tooth diseases. Expert Rev Neurother 2015; 15:355-66. [DOI: 10.1586/14737175.2015.1017471] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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32
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Brennan KM, Shy ME. New and emerging treatments of Charcot–Marie–Tooth disease. Expert Opin Orphan Drugs 2015. [DOI: 10.1517/21678707.2015.1009037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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33
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Caenorhabditis elegans Models to Study the Molecular Biology of Ataxias. Mov Disord 2015. [DOI: 10.1016/b978-0-12-405195-9.00068-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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34
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Harel T, Lupski J. Charcot-Marie-Tooth disease and pathways to molecular based therapies. Clin Genet 2014; 86:422-31. [DOI: 10.1111/cge.12393] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 03/27/2014] [Accepted: 03/28/2014] [Indexed: 01/31/2023]
Affiliation(s)
- T. Harel
- Department of Molecular and Human Genetics; Baylor College of Medicine; Houston TX USA
| | - J.R. Lupski
- Department of Molecular and Human Genetics; Baylor College of Medicine; Houston TX USA
- Department of Pediatrics; Baylor College of Medicine; Houston TX USA
- Texas Children's Hospital; Houston TX USA
- Human Genome Sequencing Center; Baylor College of Medicine; Houston TX USA
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35
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Telianidis J, Hung YH, Materia S, Fontaine SL. Role of the P-Type ATPases, ATP7A and ATP7B in brain copper homeostasis. Front Aging Neurosci 2013; 5:44. [PMID: 23986700 PMCID: PMC3750203 DOI: 10.3389/fnagi.2013.00044] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Accepted: 08/05/2013] [Indexed: 12/21/2022] Open
Abstract
Over the past two decades there have been significant advances in our understanding of copper homeostasis and the pathological consequences of copper dysregulation. Cumulative evidence is revealing a complex regulatory network of proteins and pathways that maintain copper homeostasis. The recognition of copper dysregulation as a key pathological feature in prominent neurodegenerative disorders such as Alzheimer's, Parkinson's, and prion diseases has led to increased research focus on the mechanisms controlling copper homeostasis in the brain. The copper-transporting P-type ATPases (copper-ATPases), ATP7A and ATP7B, are critical components of the copper regulatory network. Our understanding of the biochemistry and cell biology of these complex proteins has grown significantly since their discovery in 1993. They are large polytopic transmembrane proteins with six copper-binding motifs within the cytoplasmic N-terminal domain, eight transmembrane domains, and highly conserved catalytic domains. These proteins catalyze ATP-dependent copper transport across cell membranes for the metallation of many essential cuproenzymes, as well as for the removal of excess cellular copper to prevent copper toxicity. A key functional aspect of these copper transporters is their copper-responsive trafficking between the trans-Golgi network and the cell periphery. ATP7A- and ATP7B-deficiency, due to genetic mutation, underlie the inherited copper transport disorders, Menkes and Wilson diseases, respectively. Their importance in maintaining brain copper homeostasis is underscored by the severe neuropathological deficits in these disorders. Herein we will review and update our current knowledge of these copper transporters in the brain and the central nervous system, their distribution and regulation, their role in normal brain copper homeostasis, and how their absence or dysfunction contributes to disturbances in copper homeostasis and neurodegeneration.
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Affiliation(s)
- Jonathon Telianidis
- Strategic Research Centre for Molecular and Medical Research, School of Life and Environmental Sciences, Deakin UniversityBurwood, VIC, Australia
- Centre for Cellular and Molecular Biology, School of Life and Environmental Sciences, Deakin UniversityBurwood, VIC, Australia
| | - Ya Hui Hung
- Oxidation Biology Unit, Florey Institute of Neuroscience and Mental HealthParkville, VIC, Australia
- Centre for Neuroscience Research, The University of MelbourneParkville, VIC, Australia
| | - Stephanie Materia
- Strategic Research Centre for Molecular and Medical Research, School of Life and Environmental Sciences, Deakin UniversityBurwood, VIC, Australia
- Centre for Cellular and Molecular Biology, School of Life and Environmental Sciences, Deakin UniversityBurwood, VIC, Australia
| | - Sharon La Fontaine
- Strategic Research Centre for Molecular and Medical Research, School of Life and Environmental Sciences, Deakin UniversityBurwood, VIC, Australia
- Centre for Cellular and Molecular Biology, School of Life and Environmental Sciences, Deakin UniversityBurwood, VIC, Australia
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Abstract
Charcot-Marie-Tooth (CMT) disease is a heterogeneous group of inherited peripheral neuropathies in which the neuropathy is the sole or primary component of the disorder, as opposed to diseases in which the neuropathy is part of a more generalized neurologic or multisystem syndrome. Because of the great genetic heterogeneity of this condition, it can be challenging for the general neurologist to diagnose patients with specific types of CMT. This article reviews the biology of the inherited peripheral neuropathies, delineates major phenotypic features of the CMT subtypes, and suggest strategies for focusing genetic testing.
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Affiliation(s)
- Mario A Saporta
- National Laboratory of Embryonic Stem Cells, Biomedical Sciences Department, Federal University of Rio de Janeiro, Rua Republica do Peru 362/602, Rio de Janeiro 22021-040, Brazil.
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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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Abstract
Copper is an essential trace metal that is required for the catalysis of several important cellular enzymes. However, since an excess of copper can also harm cells due to its potential to catalyze the generation of toxic reactive oxygen species, transport of copper and the cellular copper content are tightly regulated. This chapter summarizes the current knowledge on the importance of copper for cellular processes and on the mechanisms involved in cellular copper uptake, storage and export. In addition, we will give an overview on disturbances of copper homeostasis that are characterized by copper overload or copper deficiency or have been connected with neurodegenerative disorders.
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Affiliation(s)
- Ivo Scheiber
- Department of Parasitology, Faculty of Science, Charles University, Prague, Czech Republic
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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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40
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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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The MFN2 V705I Variant Is Not a Disease-Causing Mutation: A Segregation Analysis in a CMT2 Family. JOURNAL OF NEURODEGENERATIVE DISEASES 2012; 2013:495873. [PMID: 26316991 PMCID: PMC4437342 DOI: 10.1155/2013/495873] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Revised: 10/23/2012] [Accepted: 10/23/2012] [Indexed: 11/20/2022]
Abstract
Charcot-Marie-Tooth (CMT) disease is a clinically and genetically heterogeneous group of disorders affecting both motor and sensory neurons in the peripheral nervous system. Mutations in the MFN2 gene cause an axonal form of CMT, CMT2A. The V705I variant in MFN2 has been previously reported as a disease-causing mutation in families with CMT2. We identified an affected index patient from an Australian multigenerational family with the V705I variant. Segregation analysis showed that the V705I variant did not segregate with the disease phenotype and was present in control individuals with an allele frequency of 4.4%. We, therefore, propose that the V705I variant is a polymorphism and not a disease-causing mutation as previously reported.
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Azzedine H, Senderek J, Rivolta C, Chrast R. Molecular genetics of charcot-marie-tooth disease: from genes to genomes. Mol Syndromol 2012; 3:204-14. [PMID: 23293578 DOI: 10.1159/000343487] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Charcot-Marie-Tooth disease (CMT) is a heterogeneous group of disorders of the peripheral nervous system, mainly characterized by distal muscle weakness and atrophy leading to motor handicap. With an estimated prevalence of 1 in 2,500, this condition is one of the most commonly inherited neurological disorders. Mutations in more than 30 genes affecting glial and/or neuronal functions have been associated with different forms of CMT leading to a substantial improvement in diagnostics of the disease and in the understanding of implicated pathophysiological mechanisms. However, recent data from systematic genetic screening performed in large cohorts of CMT patients indicated that molecular diagnosis could be established only in ∼50-70% of them, suggesting that additional genes are involved in this disease. In addition to providing an overview of genetic and functional data concerning various CMT forms, this review focuses on recent data generated through the use of highly parallel genetic technologies (SNP chips, sequence capture and next-generation DNA sequencing) in CMT families, and the current and future impact of these technologies on gene discovery and diagnostics of CMTs.
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Affiliation(s)
- H Azzedine
- Department of Medical Genetics, University of Lausanne, Lausanne, Switzerland
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Azzedine H, Senderek J, Rivolta C, Chrast R. Molecular genetics of charcot-marie-tooth disease: from genes to genomes. Mol Syndromol 2012. [PMID: 23293578 DOI: 10.1159/000343487/msy-0003-0204] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Charcot-Marie-Tooth disease (CMT) is a heterogeneous group of disorders of the peripheral nervous system, mainly characterized by distal muscle weakness and atrophy leading to motor handicap. With an estimated prevalence of 1 in 2,500, this condition is one of the most commonly inherited neurological disorders. Mutations in more than 30 genes affecting glial and/or neuronal functions have been associated with different forms of CMT leading to a substantial improvement in diagnostics of the disease and in the understanding of implicated pathophysiological mechanisms. However, recent data from systematic genetic screening performed in large cohorts of CMT patients indicated that molecular diagnosis could be established only in ∼50-70% of them, suggesting that additional genes are involved in this disease. In addition to providing an overview of genetic and functional data concerning various CMT forms, this review focuses on recent data generated through the use of highly parallel genetic technologies (SNP chips, sequence capture and next-generation DNA sequencing) in CMT families, and the current and future impact of these technologies on gene discovery and diagnostics of CMTs.
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Affiliation(s)
- H Azzedine
- Department of Medical Genetics, University of Lausanne, Lausanne, Switzerland
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Abstract
Mutations in genes expressed in Schwann cells and the axons they ensheathe cause the hereditary motor and sensory neuropathies, also known as Charcot-Marie-Tooth disease (CMT). More than 40 different genes have been shown to cause inherited neuropathies; chromosomal localizations of many other distinct inherited neuropathies have been mapped, and new genetic causes for inherited neuropathies continue to be discovered. How to keep track of all of these disorders, when to pursue genetic testing, and what tests to order for specific patients are difficult challenges for any neurologist. This review addresses these issues and provides illustrative cases to help in dealing with them. CMT serves as a living system to identify molecules necessary for normal peripheral nervous system (PNS) function. Understanding how these various molecules interact will provide a better understanding of the pathogenesis of peripheral neuropathies in general as well as other neurodegenerative disorders involving the PNS.
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Abstract
PURPOSE OF REVIEW The inherited peripheral neuropathies are a complex group of disorders caused by mutations in more than 50 genes. Scientifically, these disorders provide extensive information on molecular pathways that cause demyelination, axonal loss, and abnormal interactions between Schwann cells and the axons they ensheathe. Clinically, however, these neuropathies are confusing because it is difficult to determine what gene to test for in a given patient, inheritance patterns may differ among patients, and genetic testing is expensive. This review provides a biological context and guidelines to help neurologists better understand the basis and focus of genetic testing for these disorders. RECENT FINDINGS In the past 5 years, many of the genetic causes of inherited neuropathies have been discovered and the phenotypes of inherited neuropathies have been characterized. Clinical trials of genetic neuropathies are now underway. SUMMARY It is hoped that this review will lead to a better understanding of these fascinating neuropathies for health care professionals and that this improved understanding will facilitate treatment advances for these presently untreatable diseases.
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Affiliation(s)
- Agnes Patzko
- Wayne State University, Detroit, Michigan 48201, USA
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A novel LRSAM1 mutation is associated with autosomal dominant axonal Charcot-Marie-Tooth disease. Eur J Hum Genet 2012; 21:190-4. [PMID: 22781092 DOI: 10.1038/ejhg.2012.146] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Charcot-Marie-Tooth (CMT) disease is the most common hereditary neuropathy resulting from mutations in >30 genes expressed in either the Schwann cells or the axon of peripheral nerves. The disease is classified into demyelinating (CMT1), axonal (CMT2) or intermediate (CMTI) based on electrophysiological and pathological findings. Our study focused on the identification of a novel disease mutation in a large Sardinian family with CMT2 of autosomal dominant (AD) inheritance. All available family members were clinically evaluated and samples were collected from consenting individuals. Initially, we excluded known CMT2 genes/loci in this family. We then conducted a genome-wide linkage analysis and mapped the gene to chromosome 9q33-q34. Refined linkage and haplotype analyses defined an 11.6-Mb candidate region with a maximum LOD score of 8.06. Following exclusion of several candidate genes from the region, we targeted the LRSAM1 (leucine-rich repeat and sterile alpha motif-containing 1) gene, very recently found to be associated with autosomal recessive CMT2 in one family. For a more efficient investigation of this large gene, already available proband RNA (cDNA) was initially analyzed. Targeted DNA analysis then confirmed a novel LRSAM1 splice-site (c.2047-1G>A) mutation, causing a frameshift that introduces a stop codon three amino acids further down the new reading frame (p.Ala683ProfsX3). This mutation is located in the C-terminal RING finger motif of the encoded protein and leads to premature truncation of the protein. In the course of our work, a second LRSAM1 mutation dominantly transmitted was identified by another group. Our data further confirms that LRSAM1 mutations are associated with CMT2 of AD inheritance.
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Abstract
PURPOSE OF REVIEW The aim is to specify the genetic causes of dominantly and recessively inherited axonal forms of Charcot-Marie-Tooth disease (CMT) and review the biological basis for these disorders. RECENT FINDINGS More than 10 genes that cause axonal CMT have been identified over the past decade. Many of these genes express proteins that are ubiquitously expressed. Clinical phenotypes of many of these disorders are being studied and animal and cellular models of these neuropathies have been created. SUMMARY Identification of these new genetic causes of axonal neuropathy has not only been important for patients and their families but it has also provided exciting new information about disease mechanisms involved in neuronal degeneration. These mechanisms extend beyond the field of axonal CMT and have relevance to sensory neuropathies and motor neuron disorders. Therapeutic strategies for some of these are also provided. We hope that this review will be of interest to clinicians and scientists interested in axonal forms of CMT.
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Neves ELDA, Kok F. Clinical and neurophysiological investigation of a large family with dominant Charcot-Marie-Tooth type 2 disease with pyramidal signs. ARQUIVOS DE NEURO-PSIQUIATRIA 2011; 69:424-30. [DOI: 10.1590/s0004-282x2011000400003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Accepted: 02/10/2011] [Indexed: 11/21/2022]
Abstract
Charcot-Marie-Tooth (CMT) disease is a hereditary neuropathy of motor and sensory impairment with distal predominance. Atrophy and weakness of lower limbs are the first signs of the disease. It can be classified, with the aid of electromyography and nerve conduction studies, as demyelinating (CMT1) or axonal (CMT2). OBJECTIVE: Clinical and neurophysiological investigation of a large multigenerational family with CMT2 with autosomal dominant mode of transmission. METHOD: Fifty individuals were evaluated and neurophysiological studies performed in 22 patients. RESULTS: Thirty individuals had clinical signs of motor-sensory neuropathy. Babinski sign was present in 14 individuals. Neurophysiological study showed motor-sensory axonal polyneuropathy. CONCLUSION: The clinical and neurophysiological characteristics of this family does not differ from those observed with other forms of CMT, except for the high prevalence of Babinski sign.
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Feely SME, Laura M, Siskind CE, Sottile S, Davis M, Gibbons VS, Reilly MM, Shy ME. MFN2 mutations cause severe phenotypes in most patients with CMT2A. Neurology 2011; 76:1690-6. [PMID: 21508331 DOI: 10.1212/wnl.0b013e31821a441e] [Citation(s) in RCA: 142] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Charcot-Marie-Tooth disease type 2A (CMT2A), the most common form of CMT2, is caused by mutations in the mitofusin 2 gene (MFN2), a nuclear encoded gene essential for mitochondrial fusion and tethering the endoplasmic reticulum to mitochondria. Published CMT2A phenotypes have differed widely in severity. METHODS To determine the prevalence and phenotypes of CMT2A within our clinics we performed genetic testing on 99 patients with CMT2 evaluated at Wayne State University in Detroit and on 27 patients with CMT2 evaluated in the National Hospital for Neurology and Neurosurgery in London. We then preformed a cross-sectional analysis on our patients with CMT2A. RESULTS Twenty-one percent of patients had MFN2 mutations. Most of 27 patients evaluated with CMT2A had an earlier onset and more severe impairment than patients without CMT2A. CMT2A accounted for 91% of all our severely impaired patients with CMT2 but only 11% of mildly or moderately impaired patients. Twenty-three of 27 patients with CMT2A were nonambulatory prior to age 20 whereas just one of 78 non-CMT2A patients was nonambulatory after this age. Eleven patients with CMT2A had a pure motor neuropathy while another 5 also had profound proprioception loss. MFN2 mutations were in the GTPase domain, the coiled-coil domains, or the highly conserved R3 domain of the protein. CONCLUSIONS We find MFN2 mutations particularly likely to cause severe neuropathy that may be primarily motor or motor accompanied by prominent proprioception loss. Disruption of functional domains of the protein was particularly likely to cause neuropathy.
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Affiliation(s)
- S M E Feely
- Department of Neurology, Wayne State University, 421 Ea Canfield, Detroit, MI 48201, USA
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Saporta ASD, Sottile SL, Miller LJ, Feely SME, Siskind CE, Shy ME. Charcot-Marie-Tooth disease subtypes and genetic testing strategies. Ann Neurol 2011; 69:22-33. [PMID: 21280073 DOI: 10.1002/ana.22166] [Citation(s) in RCA: 383] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
OBJECTIVE Charcot-Marie-Tooth disease (CMT) affects 1 in 2,500 people and is caused by mutations in more than 30 genes. Identifying the genetic cause of CMT is often necessary for family planning, natural history studies, and for entry into clinical trials. However genetic testing can be both expensive and confusing to patients and physicians. METHODS We analyzed data from 1,024 of our patients to determine the percentage and features of each CMT subtype within this clinic population. We identified distinguishing clinical and physiological features of the subtypes that could be used to direct genetic testing for patients with CMT. RESULTS Of 1,024 patients evaluated, 787 received CMT diagnoses. A total of 527 patients with CMT (67%) received a genetic subtype, while 260 did not have a mutation identified. The most common CMT subtypes were CMT1A, CMT1X, hereditary neuropathy with liability to pressure palsies (HNPP), CMT1B, and CMT2A. All other subtypes accounted for less than 1% each. Eleven patients had >1 genetically identified subtype of CMT. Patients with genetically identified CMT were separable into specific groups based on age of onset and the degree of slowing of motor nerve conduction velocities. INTERPRETATION Combining features of the phenotypic and physiology groups allowed us to identify patients who were highly likely to have specific subtypes of CMT. Based on these results, we propose a strategy of focused genetic testing for CMT, illustrated in a series of flow diagrams created as testing guides.
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