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Record CJ, Pipis M, Skorupinska M, Blake J, Poh R, Polke JM, Eggleton K, Nanji T, Zuchner S, Cortese A, Houlden H, Rossor AM, Laura M, Reilly MM. Whole genome sequencing increases the diagnostic rate in Charcot-Marie-Tooth disease. Brain 2024; 147:3144-3156. [PMID: 38481354 PMCID: PMC11370804 DOI: 10.1093/brain/awae064] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 01/17/2024] [Accepted: 02/07/2024] [Indexed: 09/04/2024] Open
Abstract
Charcot-Marie-Tooth disease (CMT) is one of the most common and genetically heterogeneous inherited neurological diseases, with more than 130 disease-causing genes. Whole genome sequencing (WGS) has improved diagnosis across genetic diseases, but the diagnostic impact in CMT is yet to be fully reported. We present the diagnostic results from a single specialist inherited neuropathy centre, including the impact of WGS diagnostic testing. Patients were assessed at our specialist inherited neuropathy centre from 2009 to 2023. Genetic testing was performed using single gene testing, next-generation sequencing targeted panels, research whole exome sequencing and WGS and, latterly, WGS through the UK National Health Service. Variants were assessed using the American College of Medical Genetics and Genomics and Association for Clinical Genomic Science criteria. Excluding patients with hereditary ATTR amyloidosis, 1515 patients with a clinical diagnosis of CMT and related disorders were recruited. In summary, 621 patients had CMT1 (41.0%), 294 CMT2 (19.4%), 205 intermediate CMT (CMTi, 13.5%), 139 hereditary motor neuropathy (HMN, 9.2%), 93 hereditary sensory neuropathy (HSN, 6.1%), 38 sensory ataxic neuropathy (2.5%), 72 hereditary neuropathy with liability to pressure palsies (HNPP, 4.8%) and 53 'complex' neuropathy (3.5%). Overall, a genetic diagnosis was reached in 76.9% (1165/1515). A diagnosis was most likely in CMT1 (96.8%, 601/621), followed by CMTi (81.0%, 166/205) and then HSN (69.9%, 65/93). Diagnostic rates remained less than 50% in CMT2, HMN and complex neuropathies. The most common genetic diagnosis was PMP22 duplication (CMT1A; 505/1165, 43.3%), then GJB1 (CMTX1; 151/1165, 13.0%), PMP22 deletion (HNPP; 72/1165, 6.2%) and MFN2 (CMT2A; 46/1165, 3.9%). We recruited 233 cases to the UK 100 000 Genomes Project (100KGP), of which 74 (31.8%) achieved a diagnosis; 28 had been otherwise diagnosed since recruitment, leaving a true diagnostic rate of WGS through the 100KGP of 19.7% (46/233). However, almost half of the solved cases (35/74) received a negative report from the study, and the diagnosis was made through our research access to the WGS data. The overall diagnostic uplift of WGS for the entire cohort was 3.5%. Our diagnostic rate is the highest reported from a single centre and has benefitted from the use of WGS, particularly access to the raw data. However, almost one-quarter of all cases remain unsolved, and a new reference genome and novel technologies will be important to narrow the 'diagnostic gap'.
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Affiliation(s)
- Christopher J Record
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
| | - Menelaos Pipis
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
| | - Mariola Skorupinska
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
| | - Julian Blake
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
- Department of Clinical Neurophysiology, Norfolk and Norwich University Hospital, Norwich NR4 7UY, UK
| | - Roy Poh
- Neurogenetics Laboratory, National Hospital for Neurology and Neurosurgery, London WC1N 3BG, UK
| | - James M Polke
- Neurogenetics Laboratory, National Hospital for Neurology and Neurosurgery, London WC1N 3BG, UK
| | - Kelly Eggleton
- Neurogenetics Laboratory, National Hospital for Neurology and Neurosurgery, London WC1N 3BG, UK
| | - Tina Nanji
- Neurogenetics Laboratory, National Hospital for Neurology and Neurosurgery, London WC1N 3BG, UK
| | - Stephan Zuchner
- Dr. John T. Macdonald Foundation Department of Human Genetics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
- John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Andrea Cortese
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
| | - Henry Houlden
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
| | - Alexander M Rossor
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
| | - Matilde Laura
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
| | - Mary M Reilly
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
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Sharma S, Mahadevan A, Narayanappa G, Debnath M, Govindaraj P, Shivaram S, Seshagiri DV, Siram R, Shroti A, Bindu PS, Chickabasaviah YT, Taly AB, Nagappa M. Exploring the evidence for mitochondrial dysfunction and genetic abnormalities in the etiopathogenesis of tropical ataxic neuropathy. J Neurogenet 2024; 38:27-34. [PMID: 38975939 DOI: 10.1080/01677063.2024.2373363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Accepted: 06/24/2024] [Indexed: 07/09/2024]
Abstract
Tropical ataxic neuropathy (TAN) is characterised by ataxic polyneuropathy, degeneration of the posterior columns and pyramidal tracts, optic atrophy, and sensorineural hearing loss. It has been attributed to nutritional/toxic etiologies, but evidence for the same has been equivocal. TAN shares common clinical features with inherited neuropathies and mitochondrial disorders, it may be hypothesised that genetic abnormalities may underlie the pathophysiology of TAN. This study aimed to establish evidence for mitochondrial dysfunction by adopting an integrated biochemical and multipronged genetic analysis. Patients (n = 65) with chronic progressive ataxic neuropathy with involvement of visual and/or auditory pathways underwent deep phenotyping, genetic studies including mitochondrial DNA (mtDNA) deletion analysis, mtDNA and clinical exome sequencing (CES), and respiratory chain complex (RCC) assay. The phenotypic characteristics included dysfunction of visual (n = 14), auditory (n = 12) and visual + auditory pathways (n = 29). Reduced RCC activity was present in 13 patients. Mitochondrial DNA deletions were noted in five patients. Sequencing of mtDNA (n = 45) identified a homoplasmic variant (MT-ND6) and a heteroplasmic variant (MT-COI) in one patient each. CES (n = 45) revealed 55 variants in nuclear genes that are associated with neuropathy (n = 27), deafness (n = 7), ataxia (n = 4), and mitochondrial phenotypes (n = 5) in 36 patients. This study provides preliminary evidence that TAN is associated with a spectrum of genetic abnormalities, including those associated with mitochondrial dysfunction, which is in contradistinction from the prevailing hypothesis that TAN is related to dietary toxins. Analysing the functional relevance of these genetic variants may improve the understanding of the pathogenesis of TAN.
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Affiliation(s)
- Shivani Sharma
- Department of Neuropathology, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Anita Mahadevan
- Department of Neuropathology, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Gayathri Narayanappa
- Department of Neuropathology, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Monojit Debnath
- Department of Human Genetics, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Periyasamy Govindaraj
- Department of Neuropathology, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Sumanth Shivaram
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Doniparthi V Seshagiri
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Ramesh Siram
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Akhilesh Shroti
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Parayil S Bindu
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Yasha T Chickabasaviah
- Department of Neuropathology, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Arun B Taly
- Department of Neuropathology, National Institute of Mental Health and Neurosciences, Bengaluru, India
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Madhu Nagappa
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bengaluru, India
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Figueiredo FB, Tomaselli PJ, Hallak J, Mattiello-Sverzut AC, Covaleski APPM, Sobreira CFDR, de Paula Gouvêa S, Marques W. Genetic diversity in hereditary axonal neuropathy: Analyzing 53 Brazilian children. J Peripher Nerv Syst 2024; 29:97-106. [PMID: 38375759 DOI: 10.1111/jns.12617] [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: 01/21/2023] [Revised: 01/24/2024] [Accepted: 01/31/2024] [Indexed: 02/21/2024]
Abstract
BACKGROUND AND AIMS The genetic epidemiology of inherited neuropathies in children remains largely unknown. In this study, we specifically investigated the genetic profile of a Brazilian cohort of pediatric patients with pure or complex axonal neuropathies, a crucial knowledge in the near future for establishing treatment priorities and perspectives for this group of patients. METHODS Fifty-three pediatric patients who were assessed prior to reaching the age of 20, and who had clinical diagnoses of axonal hereditary neuropathy or presented with axonal neuropathy as the primary clinical feature, were included in the study. The recruitment of these cases took place from January 1, 2018, to December 31, 2020. The diagnosis was based on clinical and electrophysiological data. A molecular assessment was made using target-gene panel or whole-exome sequencing. Subsequently, segregation analysis was performed on available family members, and all candidate variants found were confirmed through Sanger. RESULTS A molecular diagnosis was reached in 68% of the patients (n = 36/53), considering only pathogenic and probably pathogenic variants. Variants in MFN2 (n = 15) and GJB1 (n = 3) accounted for half of the genetically confirmed patients (50%; n = 18/36). The other 18 genetically diagnosed patients had variants in several less common genes. INTERPRETATION Apart from MFN2 and GJB1 genes, universally recognized as a frequent cause of axonal neuropathies in most studied population, our Brazilian cohort of children with axonal neuropathies showed an important genetic heterogeneity, probably reflecting the multi ethnicity of the Brazilian population. Diagnostic, counseling, and future interventions should consider this characteristic.
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Affiliation(s)
- Fernanda Barbosa Figueiredo
- Neuroscience and Behavior Sciences Department, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
| | - Pedro José Tomaselli
- Neuroscience and Behavior Sciences Department, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
| | - Jaime Hallak
- Neuroscience and Behavior Sciences Department, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
- National Institute of Sciences and Technology-INCT-Translational Medicine-CNPq/FAPESP, Ribeirao Preto, Brazil
| | | | | | | | - Silmara de Paula Gouvêa
- Neuroscience and Behavior Sciences Department, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
| | - Wilson Marques
- Neuroscience and Behavior Sciences Department, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
- National Institute of Sciences and Technology-INCT-Translational Medicine-CNPq/FAPESP, Ribeirao Preto, Brazil
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Kotaich F, Caillol D, Bomont P. Neurofilaments in health and Charcot-Marie-Tooth disease. Front Cell Dev Biol 2023; 11:1275155. [PMID: 38164457 PMCID: PMC10758125 DOI: 10.3389/fcell.2023.1275155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Accepted: 10/02/2023] [Indexed: 01/03/2024] Open
Abstract
Neurofilaments (NFs) are the most abundant component of mature neurons, that interconnect with actin and microtubules to form the cytoskeleton. Specifically expressed in the nervous system, NFs present the particularity within the Intermediate Filament family of being formed by four subunits, the neurofilament light (NF-L), medium (NF-M), heavy (NF-H) proteins and α-internexin or peripherin. Here, we review the current knowledge on NF proteins and neurofilaments, from their domain structures and their model of assembly to the dynamics of their transport and degradation along the axon. The formation of the filament and its behaviour are regulated by various determinants, including post-transcriptional (miRNA and RBP proteins) and post-translational (phosphorylation and ubiquitination) modifiers. Altogether, the complex set of modifications enable the neuron to establish a stable but elastic NF array constituting the structural scaffold of the axon, while permitting the local expression of NF proteins and providing the dynamics necessary to fulfil local demands and respond to stimuli and injury. Thus, in addition to their roles in mechano-resistance, radial axonal outgrowth and nerve conduction, NFs control microtubule dynamics, organelle distribution and neurotransmission at the synapse. We discuss how the studies of neurodegenerative diseases with NF aggregation shed light on the biology of NFs. In particular, the NEFL and NEFH genes are mutated in Charcot-Marie-Tooth (CMT) disease, the most common inherited neurological disorder of the peripheral nervous system. The clinical features of the CMT forms (axonal CMT2E, CMT2CC; demyelinating CMT1F; intermediate I-CMT) with symptoms affecting the central nervous system (CNS) will allow us to further investigate the physiological roles of NFs in the brain. Thus, NF-CMT mouse models exhibit various degrees of sensory-motor deficits associated with CNS symptoms. Cellular systems brought findings regarding the dominant effect of NF-L mutants on NF aggregation and transport, although these have been recently challenged. Neurofilament detection without NF-L in recessive CMT is puzzling, calling for a re-examination of the current model in which NF-L is indispensable for NF assembly. Overall, we discuss how the fundamental and translational fields are feeding each-other to increase but also challenge our knowledge of NF biology, and to develop therapeutic avenues for CMT and neurodegenerative diseases with NF aggregation.
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Affiliation(s)
| | | | - Pascale Bomont
- ERC team, NeuroMyoGene Institute-Pathophysiology and Genetics of Neuron and Muscle, Inserm U1315, CNRS UMR5261, University of Lyon 1, Lyon, France
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Zhang Y, Pang D, Wang Z, Ma L, Chen Y, Yang L, Xiao W, Yuan H, Chang F, Ouyang H. An integrative analysis of genotype-phenotype correlation in Charcot Marie Tooth type 2A disease with MFN2 variants: A case and systematic review. Gene 2023; 883:147684. [PMID: 37536398 DOI: 10.1016/j.gene.2023.147684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 06/24/2023] [Accepted: 07/31/2023] [Indexed: 08/05/2023]
Abstract
Dominant genetic variants in the mitofusin 2 (MFN2) gene lead to Charcot-Marie-Tooth type 2A (CMT2A), a neurodegenerative disease caused by genetic defects that directly damage axons. In this study, we reported a proband with a pathogenic variant in the GTPase domain of MFN2, c.494A > G (p.His165Arg). To date, at least 184 distinct MFN2 variants identified in 944 independent probands have been reported in 131 references. However, the field of medical genetics has long been challenged by how genetic variation in the MFN2 gene is associated with disease phenotypes. Here, by collating the MFN2 variant data and patient clinical information from Leiden Open Variant Database 3.0, NCBI clinvar database, and available related references in PubMed, we determined the mutation frequency, age of onset, sex ratio, and geographical distribution. Furthermore, the results of an analysis examining the relationship between variants and phenotypes from multiple genetic perspectives indicated that insertion and deletions (indels), copy number variants (CNVs), duplication variants, and nonsense mutations in single nucleotide variants (SNVs) tend to be pathogenic, and the results emphasized the importance of the GTPase domain to the structure and function of MFN2. Overall, three reliable classification methods of MFN2 genotype-phenotype associations provide insights into the prediction of CMT2A disease severity. Of course, there are still many MFN2 variants that have not been given clear clinical significance, which requires clinicians to make more accurate clinical diagnoses.
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Affiliation(s)
- Yuanzhu Zhang
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Animal Sciences, Jilin University, Changchun 130062, China.
| | - Daxin Pang
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Animal Sciences, Jilin University, Changchun 130062, China; Chongqing Research Institute, Jilin University, Chongqing 401120, China; Chongqing Jitang Biotechnology Research Institute Co., Ltd., Chongqing 401120, China.
| | - Ziru Wang
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Animal Sciences, Jilin University, Changchun 130062, China.
| | - Lerong Ma
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Animal Sciences, Jilin University, Changchun 130062, China.
| | - Yiwu Chen
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Animal Sciences, Jilin University, Changchun 130062, China.
| | - Lin Yang
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Animal Sciences, Jilin University, Changchun 130062, China.
| | - Wenyu Xiao
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Animal Sciences, Jilin University, Changchun 130062, China.
| | - Hongming Yuan
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Animal Sciences, Jilin University, Changchun 130062, China; Chongqing Research Institute, Jilin University, Chongqing 401120, China.
| | - Fei Chang
- Department of Orthopedics, The Second Hospital of Jilin University, Changchun 130022, China.
| | - Hongsheng Ouyang
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Animal Sciences, Jilin University, Changchun 130062, China; Chongqing Research Institute, Jilin University, Chongqing 401120, China; Chongqing Jitang Biotechnology Research Institute Co., Ltd., Chongqing 401120, China.
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Record CJ, Skorupinska M, Laura M, Rossor AM, Pareyson D, Pisciotta C, Feely SME, Lloyd TE, Horvath R, Sadjadi R, Herrmann DN, Li J, Walk D, Yum SW, Lewis RA, Day J, Burns J, Finkel RS, Saporta MA, Ramchandren S, Weiss MD, Acsadi G, Fridman V, Muntoni F, Poh R, Polke JM, Zuchner S, Shy ME, Scherer SS, Reilly MM. Genetic analysis and natural history of Charcot-Marie-Tooth disease CMTX1 due to GJB1 variants. Brain 2023; 146:4336-4349. [PMID: 37284795 PMCID: PMC10545504 DOI: 10.1093/brain/awad187] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 05/05/2023] [Accepted: 05/20/2023] [Indexed: 06/08/2023] Open
Abstract
Charcot-Marie-Tooth disease (CMT) due to GJB1 variants (CMTX1) is the second most common form of CMT. It is an X-linked disorder characterized by progressive sensory and motor neuropathy with males affected more severely than females. Many reported GJB1 variants remain classified as variants of uncertain significance (VUS). In this large, international, multicentre study we prospectively collected demographic, clinical and genetic data on patients with CMT associated with GJB1 variants. Pathogenicity for each variant was defined using adapted American College of Medical Genetics criteria. Baseline and longitudinal analyses were conducted to study genotype-phenotype correlations, to calculate longitudinal change using the CMT Examination Score (CMTES), to compare males versus females, and pathogenic/likely pathogenic (P/LP) variants versus VUS. We present 387 patients from 295 families harbouring 154 variants in GJB1. Of these, 319 patients (82.4%) were deemed to have P/LP variants, 65 had VUS (16.8%) and three benign variants (0.8%; excluded from analysis); an increased proportion of patients with P/LP variants compared with using ClinVar's classification (74.6%). Male patients (166/319, 52.0%, P/LP only) were more severely affected at baseline. Baseline measures in patients with P/LP variants and VUS showed no significant differences, and regression analysis suggested the disease groups were near identical at baseline. Genotype-phenotype analysis suggested c.-17G>A produces the most severe phenotype of the five most common variants, and missense variants in the intracellular domain are less severe than other domains. Progression of disease was seen with increasing CMTES over time up to 8 years follow-up. Standard response mean (SRM), a measure of outcome responsiveness, peaked at 3 years with moderate responsiveness [change in CMTES (ΔCMTES) = 1.3 ± 2.6, P = 0.00016, SRM = 0.50]. Males and females progressed similarly up to 8 years, but baseline regression analysis suggested that over a longer period, females progress more slowly. Progression was most pronounced for mild phenotypes (CMTES = 0-7; 3-year ΔCMTES = 2.3 ± 2.5, P = 0.001, SRM = 0.90). Enhanced variant interpretation has yielded an increased proportion of GJB1 variants classified as P/LP and will aid future variant interpretation in this gene. Baseline and longitudinal analysis of this large cohort of CMTX1 patients describes the natural history of the disease including the rate of progression; CMTES showed moderate responsiveness for the whole group at 3 years and higher responsiveness for the mild group at 3, 4 and 5 years. These results have implications for patient selection for upcoming clinical trials.
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Affiliation(s)
- Christopher J Record
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, WC1N 3BG, UK
| | - Mariola Skorupinska
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, WC1N 3BG, UK
| | - Matilde Laura
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, WC1N 3BG, UK
| | - Alexander M Rossor
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, WC1N 3BG, UK
| | - Davide Pareyson
- Department of Clinical Neurosciences, Fondazione IRCCS Istituto Neurologico Carlo Besta, 20133 Milan, Italy
| | - Chiara Pisciotta
- Department of Clinical Neurosciences, Fondazione IRCCS Istituto Neurologico Carlo Besta, 20133 Milan, Italy
| | - Shawna M E Feely
- Department of Neurology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Thomas E Lloyd
- Departments of Neurology and Neuroscience, John Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Rita Horvath
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 0PY, UK
| | - Reza Sadjadi
- Department of Neurology, Massachusetts General Hospital, Boston, MA 02114, USA
| | - David N Herrmann
- Department of Neurology, University of Rochester, Rochester, NY 14618, USA
| | - Jun Li
- Department of Neurology, Houston Methodist Hospital, Houston, TX 77030, USA
| | - David Walk
- Department of Neurology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Sabrina W Yum
- Department of Neurology, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Richard A Lewis
- Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - John Day
- Department of Neurology, Stanford University, Stanford, CA 94304, USA
| | - Joshua Burns
- University of Sydney School of Health Sciences, Faculty of Medicine and Health; Paediatric Gait Analysis Service of New South Wales, Sydney Children’s Hospitals Network, Sydney, 2145Australia
| | - Richard S Finkel
- Department of Neurology, Nemours Children’s Hospital, Orlando, FL 32827, USA
| | - Mario A Saporta
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Sindhu Ramchandren
- Department of Neurology, Wayne State University, Detroit, MI 48201, USA
- The Janssen Pharmaceutical Companies of Johnson & Johnson, Titusville, NJ 08560, USA
| | - Michael D Weiss
- Department of Neurology, University of Washington, Seattle, WA, 98195USA
| | - Gyula Acsadi
- Connecticut Children’s Medical Center, Hartford, CT 06106, USA
| | - Vera Fridman
- Department of Neurology, University of Colorado Denver School of Medicine, Aurora, CO 80045, USA
| | - Francesco Muntoni
- The Dubowitz Neuromuscular Centre, NIHR Great Ormond Street Hospital Biomedical Research Centre, Great Ormond Street Institute of Child Health University College London, and Great Ormond Street Hospital Trust, London, WC1N 1EH, UK
| | - Roy Poh
- Neurogenetics Laboratory, National Hospital for Neurology and Neurosurgery, London, WC1N 3BG, UK
| | - James M Polke
- Neurogenetics Laboratory, National Hospital for Neurology and Neurosurgery, London, WC1N 3BG, UK
| | - Stephan Zuchner
- Dr. John T. Macdonald Foundation Department of Human Genetics and John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Michael E Shy
- Department of Neurology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Steven S Scherer
- Department of Neurology, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Mary M Reilly
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, WC1N 3BG, UK
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Kim YG, Kwon H, Park JH, Nam SH, Ha C, Shin S, Heo WY, Kim HJ, Chung KW, Jang JH, Kim JW, Choi BO. Whole-genome sequencing in clinically diagnosed Charcot-Marie-Tooth disease undiagnosed by whole-exome sequencing. Brain Commun 2023; 5:fcad139. [PMID: 37180992 PMCID: PMC10174204 DOI: 10.1093/braincomms/fcad139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 03/16/2023] [Accepted: 04/27/2023] [Indexed: 05/16/2023] Open
Abstract
Whole-genome sequencing is the most comprehensive form of next-generation sequencing method. We aimed to assess the additional diagnostic yield of whole-genome sequencing in patients with clinically diagnosed Charcot-Marie-Tooth disease when compared with whole-exome sequencing, which has not been reported in the literature. Whole-genome sequencing was performed on 72 families whose genetic cause of clinically diagnosed Charcot-Marie-Tooth disease was not revealed after the whole-exome sequencing and 17p12 duplication screening. Among the included families, 14 (19.4%) acquired genetic diagnoses that were compatible with their phenotypes. The most common factor that led to the additional diagnosis in the whole-genome sequencing was genotype-driven analysis (four families, 4/14), in which a wider range of genes, not limited to peripheral neuropathy-related genes, were analysed. Another four families acquired diagnosis due to the inherent advantage of whole-genome sequencing such as better coverage than the whole-exome sequencing (two families, 2/14), structural variants (one family, 1/14) and non-coding variants (one family, 1/14). In conclusion, an evident gain in diagnostic yield was obtained from whole-genome sequencing of the whole-exome sequencing-negative cases. A wide range of genes, not limited to inherited peripheral neuropathy-related genes, should be targeted during whole-genome sequencing.
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Affiliation(s)
- Young-gon Kim
- Correspondence to: Jong-Won Kim, MD, PhD Department of Laboratory Medicine and Genetics, Samsung Medical Center 81 Irwon-ro, Gangnam-gu, Seoul 06351, South Korea E-mail:
| | | | - Jong-ho Park
- Clinical Genomics Center, Samsung Medical Center, Seoul 06351, Republic of Korea
| | - Soo Hyun Nam
- Cell and Gene Therapy Institute (CGTI), Samsung Medical Center, Seoul 06351, Republic of Korea
| | - Changhee Ha
- Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, Republic of Korea
| | - Sunghwan Shin
- Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, Republic of Korea
| | - Won Young Heo
- Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, Republic of Korea
| | - Hye Jin Kim
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, Republic of Korea
| | - Ki Wha Chung
- Department of Biological Sciences, Kongju National University, Gongju 32588, South Korea
| | - Ja-Hyun Jang
- Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, Republic of Korea
| | - Jong-Won Kim
- Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, Republic of Korea
- Clinical Genomics Center, Samsung Medical Center, Seoul 06351, Republic of Korea
| | - Byung-Ok Choi
- Correspondence may also be sent to: Byung-Ok Choi, MD, PhD Department of Neurology, Samsung Medical Center 81 Irwon-ro, Gangnam-gu, Seoul 06351, South Korea E-mail:
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8
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Lysko DE, Meireles AM, Folland C, McNamara E, Laing NG, Lamont PJ, Ravenscroft G, Talbot WS. Partial loss-of-function variant in neuregulin 1 identified in family with heritable peripheral neuropathy. Hum Mutat 2022; 43:1216-1223. [PMID: 35485770 PMCID: PMC9357049 DOI: 10.1002/humu.24393] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 03/24/2022] [Accepted: 04/27/2022] [Indexed: 11/11/2022]
Abstract
Neuregulin 1 signals are essential for the development and function of Schwann cells, which form the myelin sheath on peripheral axons. Disruption of myelin in the peripheral nervous system can lead to peripheral neuropathy, which is characterized by reduced axonal conduction velocity and sensorimotor deficits. Charcot-Marie-Tooth disease is a group of heritable peripheral neuropathies that may be caused by variants in nearly 100 genes. Despite the evidence that Neuregulin 1 is essential for many aspects of Schwann cell development, previous studies have not reported variants in the neuregulin 1 gene (NRG1) in patients with peripheral neuropathy. We have identified a rare missense variant in NRG1 that is homozygous in a patient with sensory and motor deficits consistent with mixed axonal and de-myelinating peripheral neuropathy. Our in vivo functional studies in zebrafish indicate that the patient variant partially reduces NRG1 function. This study tentatively suggests that variants at the NRG1 locus may cause peripheral neuropathy and that NRG1 should be investigated in families with peripheral neuropathy of unknown cause.
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Affiliation(s)
- Daniel E Lysko
- Department of Developmental Biology, Stanford University, Stanford, CA 94305, USA
| | - Ana M Meireles
- Department of Developmental Biology, Stanford University, Stanford, CA 94305, USA
| | - Chiara Folland
- Harry Perkins Institute of Medical Research, Nedlands, WA, 6009, Australia
- Centre of Medical Research, University of Western Australia, Nedlands, WA, 6009, Australia
| | - Elyshia McNamara
- Harry Perkins Institute of Medical Research, Nedlands, WA, 6009, Australia
- Centre of Medical Research, University of Western Australia, Nedlands, WA, 6009, Australia
| | - Nigel G Laing
- Harry Perkins Institute of Medical Research, Nedlands, WA, 6009, Australia
- Centre of Medical Research, University of Western Australia, Nedlands, WA, 6009, Australia
| | | | - Gianina Ravenscroft
- Harry Perkins Institute of Medical Research, Nedlands, WA, 6009, Australia
- Centre of Medical Research, University of Western Australia, Nedlands, WA, 6009, Australia
- School of Biomedical Sciences, University of Western Australia, Nedlands, WA, 6009, Australia
| | - William S Talbot
- Department of Developmental Biology, Stanford University, Stanford, CA 94305, USA
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9
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Vitale G, Mattiaccio A, Conti A, Turco L, Seri M, Piscaglia F, Morelli MC. Genetics in Familial Intrahepatic Cholestasis: Clinical Patterns and Development of Liver and Biliary Cancers: A Review of the Literature. Cancers (Basel) 2022; 14:cancers14143421. [PMID: 35884482 PMCID: PMC9322180 DOI: 10.3390/cancers14143421] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 07/10/2022] [Accepted: 07/12/2022] [Indexed: 02/06/2023] Open
Abstract
The family of inherited intrahepatic cholestasis includes autosomal recessive cholestatic rare diseases of childhood involved in bile acids secretion or bile transport defects. Specific genetic pathways potentially cause many otherwise unexplained cholestasis or hepatobiliary tumours in a healthy liver. Lately, next-generation sequencing and whole-exome sequencing have improved the diagnostic procedures of familial intrahepatic cholestasis (FIC), as well as the discovery of several genes responsible for FIC. Moreover, mutations in these genes, even in the heterozygous status, may be responsible for cryptogenic cholestasis in both young and adults. Mutations in FIC genes can influence serum and hepatic levels of bile acids. Experimental studies on the NR1H4 gene have shown that high bile acids concentrations cause excessive production of inflammatory cytokines, resistance to apoptosis, and increased cell regeneration, all risk conditions for developing hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA). NR1H4 gene encodes farnesoid X-activated receptor having a pivotal role in bile salts synthesis. Moreover, HCC and CCA can emerge in patients with several FIC genes such as ABCB11, ABCB4 and TJP2. Herein, we reviewed the available data on FIC-related hepatobiliary cancers, reporting on genetics to the pathophysiology, the risk factors and the clinical presentation.
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Affiliation(s)
- Giovanni Vitale
- Internal Medicine Unit for the Treatment of Severe Organ Failure, IRCCS Azienda Ospedaliero-Universitaria di Bologna, 40138 Bologna, Italy; (L.T.); (M.C.M.)
- Correspondence:
| | - Alessandro Mattiaccio
- U.O. Genetica Medica, IRCCS Azienda Ospedaliero-Universitaria di Bologna, 40138 Bologna, Italy; (A.M.); (A.C.); (M.S.)
- Department of Medical and Surgical Sciences (DIMEC), Alma Mater Studiorum-University di Bologna, 40138 Bologna, Italy
| | - Amalia Conti
- U.O. Genetica Medica, IRCCS Azienda Ospedaliero-Universitaria di Bologna, 40138 Bologna, Italy; (A.M.); (A.C.); (M.S.)
| | - Laura Turco
- Internal Medicine Unit for the Treatment of Severe Organ Failure, IRCCS Azienda Ospedaliero-Universitaria di Bologna, 40138 Bologna, Italy; (L.T.); (M.C.M.)
| | - Marco Seri
- U.O. Genetica Medica, IRCCS Azienda Ospedaliero-Universitaria di Bologna, 40138 Bologna, Italy; (A.M.); (A.C.); (M.S.)
- Department of Medical and Surgical Sciences (DIMEC), Alma Mater Studiorum-University di Bologna, 40138 Bologna, Italy
| | - Fabio Piscaglia
- Division of Internal Medicine, Hepatobiliary and Immunoallergic Diseases, IRCCS Azienda Ospedaliero-Universitaria di Bologna, 40138 Bologna, Italy;
| | - Maria Cristina Morelli
- Internal Medicine Unit for the Treatment of Severe Organ Failure, IRCCS Azienda Ospedaliero-Universitaria di Bologna, 40138 Bologna, Italy; (L.T.); (M.C.M.)
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10
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Genetic Workup for Charcot–Marie–Tooth Neuropathy: A Retrospective Single-Site Experience Covering 15 Years. Life (Basel) 2022; 12:life12030402. [PMID: 35330153 PMCID: PMC8948690 DOI: 10.3390/life12030402] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 03/04/2022] [Accepted: 03/07/2022] [Indexed: 11/16/2022] Open
Abstract
Charcot–Marie–Tooth (CMT) disease is the most commonly inherited neurological disorder. This study includes patients affected by CMT during regular follow-ups at the CMT clinic in Genova, a neuromuscular university center in the northwest of Italy, with the aim of describing the genetic distribution of CMT subtypes in our cohort and reporting a peculiar phenotype. Since 2004, 585 patients (447 index cases) have been evaluated at our center, 64.9% of whom have a demyelinating neuropathy and 35.1% of whom have an axonal neuropathy. A genetic diagnosis was achieved in 66% of all patients, with the following distribution: CMT1A (48%), HNPP (14%), CMT1X (13%), CMT2A (5%), and P0-related neuropathies (7%), accounting all together for 87% of all the molecularly defined neuropathies. Interestingly, we observe a peculiar phenotype with initial exclusive lower limb involvement as well as lower limb involvement that is maintained over time, which we have defined as a “strictly length-dependent” phenotype. Most patients with this clinical presentation shared variants in either HSPB1 or MPZ genes. The identification of distinctive phenotypes such as this one may help to address genetic diagnosis. In conclusion, we describe our diagnostic experiences as a multidisciplinary outpatient clinic, combining a gene-by-gene approach or targeted gene panels based on clinical presentation.
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11
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Grosz BR, Stevanovski I, Negri S, Ellis M, Barnes S, Reddel S, Vucic S, Nicholson GA, Cortese A, Kumar KR, Deveson IW, Kennerson ML. Long read sequencing overcomes challenges in the diagnosis of
SORD
neuropathy. J Peripher Nerv Syst 2022; 27:120-126. [DOI: 10.1111/jns.12485] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 02/13/2022] [Accepted: 02/22/2022] [Indexed: 10/19/2022]
Affiliation(s)
- Bianca R Grosz
- Northcott Neuroscience Laboratory ANZAC Research Institute Concord NSW Australia
| | - Igor Stevanovski
- Kinghorn Centre for Clinical Genomics Garvan Institute of Medical Research Sydney NSW Australia
| | - Sara Negri
- Istituiti Clinici Scientifici Maugeri IRCCS Environmental Research Center Pavia Italy
| | - Melina Ellis
- Northcott Neuroscience Laboratory ANZAC Research Institute Concord NSW Australia
- Sydney Medical School University of Sydney Camperdown NSW Australia
| | - Stephanie Barnes
- Sydney Medical School University of Sydney Camperdown NSW Australia
- Department of Neurology Concord Repatriation General Hospital Concord NSW Australia
- Faculty of Medicine University of Notre Dame Sydney Australia
- Department of Neurology Hornsby Ku‐ring‐Gai Hospital Sydney Australia
| | - Stephen Reddel
- Sydney Medical School University of Sydney Camperdown NSW Australia
- Department of Neurology Concord Repatriation General Hospital Concord NSW Australia
| | - Steve Vucic
- Sydney Medical School University of Sydney Camperdown NSW Australia
- Department of Neurology Concord Repatriation General Hospital Concord NSW Australia
| | - Garth A Nicholson
- Sydney Medical School University of Sydney Camperdown NSW Australia
- Department of Neurology Concord Repatriation General Hospital Concord NSW Australia
- Molecular Medicine Laboratory Concord Repatriation General Hospital Concord NSW Australia
| | - Andrea Cortese
- MRC Centre for Neuromuscular Diseases, Department of Neuromuscular Diseases UCL Queen Square Institute of Neurology London UK
- Department of Brain and Behavioral Sciences University of Pavia Pavia Italy
| | - Kishore R Kumar
- Kinghorn Centre for Clinical Genomics Garvan Institute of Medical Research Sydney NSW Australia
- Sydney Medical School University of Sydney Camperdown NSW Australia
- Department of Neurology Concord Repatriation General Hospital Concord NSW Australia
- Molecular Medicine Laboratory Concord Repatriation General Hospital Concord NSW Australia
| | - Ira W Deveson
- Kinghorn Centre for Clinical Genomics Garvan Institute of Medical Research Sydney NSW Australia
- St Vincent’s Clinical School University of New South Wales Sydney NSW Australia
| | - Marina L Kennerson
- Northcott Neuroscience Laboratory ANZAC Research Institute Concord NSW Australia
- Sydney Medical School University of Sydney Camperdown NSW Australia
- Molecular Medicine Laboratory Concord Repatriation General Hospital Concord NSW Australia
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12
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Narayanaswami P, Živković S. Molecular and Genetic Therapies. Neuromuscul Disord 2022. [DOI: 10.1016/b978-0-323-71317-7.00011-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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13
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Nagappa M, Sharma S, Govindaraj P, Chickabasaviah Y, Siram R, Shroti A, Seshagiri D, Debnath M, Bindu P, Taly A. Genetic spectrum of inherited neuropathies in India. Ann Indian Acad Neurol 2022; 25:407-416. [PMID: 35936615 PMCID: PMC9350795 DOI: 10.4103/aian.aian_269_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 04/29/2022] [Accepted: 04/30/2022] [Indexed: 11/17/2022] Open
Abstract
Background and Objectives: Charcot-Marie-Tooth (CMT) disease is the commonest inherited neuromuscular disorder and has heterogeneous manifestations. Data regarding genetic basis of CMT from India is limited. This study aims to report the variations by using high throughput sequencing in Indian CMT cohort. Methods: Fifty-five probands (M:F 29:26) with suspected inherited neuropathy underwent genetic testing (whole exome: 31, clinical exome: 17 and targeted panel: 7). Their clinical and genetic data were analysed. Results: Age at onset ranged from infancy to 54 years. Clinical features included early-onset neuropathy (n=23), skeletal deformities (n=45), impaired vision (n=8), impaired hearing (n=6), facial palsy (n=8), thickened nerves (n=4), impaired cognition (n=5), seizures (n=5), pyramidal signs (n=7), ataxia (n=8) and vocal cord palsy, slow tongue movements and psychosis in one patient each. Twenty-eight patients had demyelinating electrophysiology. Abnormal visual and auditory evoked potentials were noted in 60.60% and 37.5% respectively. Sixty two variants were identified in 37 genes including variants of uncertain significance (n=34) and novel variants (n=45). Eleven patients had additional variations in genes implicated in CMTs/ other neurological disorders. Ten patients did not have variations in neuropathy associated genes, but had variations in genes implicated in other neurological disorders. In seven patients, no variations were detected. Conclusion: In this single centre cohort study from India, genetic diagnosis could be established in 87% of patients with inherited neuropathy. The identified spectrum of genetic variations adds to the pool of existing data and provides a platform for validation studies in cell culture or animal model systems.
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14
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Choi KE, Yim J, Kim M, Lee JH. A Novel HNPP Phenotype in Charcot-Marie-Tooth Type 2E With c.1319C>T Missense Mutation in the NEFL Gene. J Clin Neurol 2022; 18:244-246. [PMID: 35274844 PMCID: PMC8926773 DOI: 10.3988/jcn.2022.18.2.244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 10/26/2021] [Accepted: 10/26/2021] [Indexed: 11/29/2022] Open
Affiliation(s)
- Ko-Eun Choi
- Department of Neurology, Seoul St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Jisook Yim
- Department of Laboratory Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea
- Catholic Genetic Laboratory Center, Seoul St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Myungshin Kim
- Department of Laboratory Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea
- Catholic Genetic Laboratory Center, Seoul St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Jung Hwan Lee
- Department of Neurology, Seoul St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
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15
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Narayanan RK, Brewer MH, Perez-Siles G, Ellis M, Ly C, Burgess A, Neumann B, Nicholson GA, Vucic S, Kennerson ML. Charcot-Marie-tooth disease causing mutation (p.R158H) in pyruvate dehydrogenase kinase 3 (PDK3) affects synaptic transmission, ATP production and causes neurodegeneration in a CMTX6 C. elegans model. Hum Mol Genet 2021; 31:133-145. [PMID: 34387338 PMCID: PMC8682796 DOI: 10.1093/hmg/ddab228] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 08/03/2021] [Accepted: 08/04/2021] [Indexed: 12/05/2022] Open
Abstract
Charcot–Marie-Tooth (CMT) is a commonly inherited, non-fatal neurodegenerative disorder that affects sensory and motor neurons in patients. More than 90 genes are known to cause axonal and demyelinating forms of CMT. The p.R158H mutation in the pyruvate dehydrogenase kinase 3 (PDK3) gene is the genetic cause for an X linked form of axonal CMT (CMTX6). In vitro studies using patient fibroblasts and iPSC-derived motor neurons have shown that this mutation causes deficits in energy metabolism and mitochondrial function. Animal models that recapitulate pathogenic in vivo events in patients are crucial for investigating mechanisms of axonal degeneration and developing therapies for CMT. We have developed a C. elegans model of CMTX6 by knocking-in the p.R158H mutation in pdhk-2, the ortholog of PDK3. In addition, we have developed animal models overexpressing the wild type and mutant form of human PDK3 specifically in the GABAergic motor neurons of C. elegans. CMTX6 mutants generated in this study exhibit synaptic transmission deficits, locomotion defects and show signs of progressive neurodegeneration. Furthermore, the CMTX6 in vivo models display energy deficits that recapitulate the phenotype observed in patient fibroblasts and iPSC-derived motor neurons. Our CMTX6 animals represent the first in vivo model for this form of CMT and have provided novel insights into the cellular function and metabolic pathways perturbed by the p.R158H mutation, all the while closely replicating the clinical presentation observed in CMTX6 patients.
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Affiliation(s)
- Ramesh K Narayanan
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Sydney, NSW, Australia.,Sydney Medical School, University of Sydney, Sydney, NSW, Australia
| | - Megan H Brewer
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Sydney, NSW, Australia
| | - Gonzalo Perez-Siles
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Sydney, NSW, Australia.,Sydney Medical School, University of Sydney, Sydney, NSW, Australia
| | - Melina Ellis
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Sydney, NSW, Australia
| | - Carolyn Ly
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Sydney, NSW, Australia
| | - Andrew Burgess
- Cell Division Laboratory, ANZAC Research Institute, Sydney, NSW, Australia
| | - Brent Neumann
- Neuroscience Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, Victoria, Australia
| | - Garth A Nicholson
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Sydney, NSW, Australia.,Sydney Medical School, University of Sydney, Sydney, NSW, Australia.,Molecular Medicine Laboratory, Concord General Repatriation Hospital, Sydney, NSW, Australia
| | - Steve Vucic
- Concord Clinical School, University of Sydney, Sydney, NSW, Australia
| | - Marina L Kennerson
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Sydney, NSW, Australia.,Sydney Medical School, University of Sydney, Sydney, NSW, Australia.,Molecular Medicine Laboratory, Concord General Repatriation Hospital, Sydney, NSW, Australia
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16
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Felice KJ, Whitaker CH, Khorasanizadeh S. Diagnostic yield of advanced genetic testing in patients with hereditary neuropathies: A retrospective single-site study. Muscle Nerve 2021; 64:454-461. [PMID: 34232518 DOI: 10.1002/mus.27368] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 06/29/2021] [Accepted: 07/04/2021] [Indexed: 11/09/2022]
Abstract
INTRODUCTION/AIMS Advanced genetic testing including next-generation sequencing (AGT/NGS) has facilitated DNA testing in the clinical setting and greatly expanded new gene discovery for the Charcot-Marie-Tooth neuropathies and other hereditary neuropathies (CMT/HN). Herein, we report AGT/NGS results, clinical findings, and diagnostic yield in a cohort of CMT/HN patients evaluated at our neuropathy care center. METHODS We reviewed the medical records of all patients with suspected CMT/HN who underwent AGT/NGS at the Hospital for Special Care from January 2017 through January 2020. Patients with variants reported as pathogenic or likely pathogenic were included for further clinical review. RESULTS We ordered AGT/NGS on 108 patients with suspected CMT/HN. Of these, pathogenic or likely pathogenic variants were identified in 17 patients (diagnostic yield, 15.7%), including 6 (35%) with PMP22 duplications; 3 (18%) with MPZ variants; 2 (12%) with MFN2 variants; and 1 each with NEFL, IGHMBP2, GJB1, BSCL2, DNM2, and TTR variants. Diagnostic yield increased to 31.0% for patients with a positive family history. DISCUSSION AGT/NGS panels can provide specific genetic diagnoses for a subset of patients with CMT/HN disorders, which improves disease and genetic counseling and prepares patients for disease-focused therapies. Despite these advancements, many patients with known or suspected CMT/HN disorders remain without a specific genetic diagnosis. Continued advancements in genetic testing, such as multiomic technology and better understanding of genotype-phenotype correlation, will further improve detection rates for patients with suspected CMT/HN disorders.
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Affiliation(s)
- Kevin J Felice
- Department of Neuromuscular Medicine, Hospital for Special Care, New Britain, Connecticut, USA
| | - Charles H Whitaker
- Department of Neuromuscular Medicine, Hospital for Special Care, New Britain, Connecticut, USA
| | - Sadaf Khorasanizadeh
- Department of Neuromuscular Medicine, Hospital for Special Care, New Britain, Connecticut, USA
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17
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Stone EJ, Kolb SJ, Brown A. A review and analysis of the clinical literature on Charcot-Marie-Tooth disease caused by mutations in neurofilament protein L. Cytoskeleton (Hoboken) 2021; 78:97-110. [PMID: 33993654 PMCID: PMC10174713 DOI: 10.1002/cm.21676] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 05/05/2021] [Accepted: 05/06/2021] [Indexed: 01/22/2023]
Abstract
Charcot-Marie-Tooth disease (CMT) is one of the most common inherited neurological disorders and can be caused by mutations in over 100 different genes. One of the causative genes is NEFL on chromosome 8 which encodes neurofilament light protein (NEFL), one of five proteins that co-assemble to form neurofilaments. At least 34 different CMT-causing mutations in NEFL have been reported which span the head, rod, and tail domains of the protein. The majority of these mutations are inherited dominantly, but some are inherited recessively. The resulting disease is classified variably in clinical reports based on electrodiagnostic studies as either axonal (type 2; CMT2E), demyelinating (type 1; CMT1F), or a form intermediate between the two (dominant intermediate; DI-CMTG). In this article, we first present a brief introduction to CMT and neurofilaments. We then collate and analyze the data from the clinical literature on the disease classification, age of onset and electrodiagnostic test results for the various mutations. We find that mutations in the head, rod, and tail domains can all cause disease with early onset and profound neurological impairment, with a trend toward greater severity for head domain mutations. We also find that the disease classification does not correlate with specific mutation or domain. In fact, different individuals with the same mutation can be classified as having axonal, demyelinating, or dominant intermediate forms of the disease. This suggests that the classification of the disease as CMT2E, CMT1F or DI-CMTG has more to do with variable disease presentation than to differences in the underlying disease mechanism, which is most likely primarily axonal in all cases.
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Affiliation(s)
- Elizabeth J Stone
- Department of Neuroscience, Ohio State University, Columbus, Ohio, USA.,Neuroscience Graduate Program, Ohio State University, Columbus, Ohio, USA
| | - Stephen J Kolb
- Department of Neurology, Ohio State University, Columbus, Ohio, USA.,Department of Biological Chemistry and Pharmacology, Ohio State University, Columbus, Ohio, USA
| | - Anthony Brown
- Department of Neuroscience, Ohio State University, Columbus, Ohio, USA
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18
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Yubero D, Natera-de Benito D, Pijuan J, Armstrong J, Martorell L, Fernàndez G, Maynou J, Jou C, Roldan M, Ortez C, Nascimento A, Hoenicka J, Palau F. The Increasing Impact of Translational Research in the Molecular Diagnostics of Neuromuscular Diseases. Int J Mol Sci 2021; 22:4274. [PMID: 33924139 PMCID: PMC8074304 DOI: 10.3390/ijms22084274] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 04/13/2021] [Accepted: 04/16/2021] [Indexed: 12/12/2022] Open
Abstract
The diagnosis of neuromuscular diseases (NMDs) has been progressively evolving from the grouping of clinical symptoms and signs towards the molecular definition. Optimal clinical, biochemical, electrophysiological, electrophysiological, and histopathological characterization is very helpful to achieve molecular diagnosis, which is essential for establishing prognosis, treatment and genetic counselling. Currently, the genetic approach includes both the gene-targeted analysis in specific clinically recognizable diseases, as well as genomic analysis based on next-generation sequencing, analyzing either the clinical exome/genome or the whole exome or genome. However, as of today, there are still many patients in whom the causative genetic variant cannot be definitely established and variants of uncertain significance are often found. In this review, we address these drawbacks by incorporating two additional biological omics approaches into the molecular diagnostic process of NMDs. First, functional genomics by introducing experimental cell and molecular biology to analyze and validate the variant for its biological effect in an in-house translational diagnostic program, and second, incorporating a multi-omics approach including RNA-seq, metabolomics, and proteomics in the molecular diagnosis of neuromuscular disease. Both translational diagnostics programs and omics are being implemented as part of the diagnostic process in academic centers and referral hospitals and, therefore, an increase in the proportion of neuromuscular patients with a molecular diagnosis is expected. This improvement in the process and diagnostic performance of patients will allow solving aspects of their health problems in a precise way and will allow them and their families to take a step forward in their lives.
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Affiliation(s)
- Dèlia Yubero
- Department of Genetic and Molecular Medicine—IPER, Hospital Sant Joan de Déu and Institut de Recerca Sant Joan de Déu, 08950 Barcelona, Spain; (D.Y.); (J.A.); (L.M.); (G.F.); (J.M.); (M.R.)
- Center for Biomedical Research Network on Rare Diseases (CIBERER), ISCIII, 08950 Barcelona, Spain;
| | - Daniel Natera-de Benito
- Neuromuscular Unit, Department of Pediatric Neurology, Hospital Sant Joan de Déu and Institut de Recerca Sant Joan de Déu, 08950 Barcelona, Spain; (D.N.-d.B.); (C.O.)
| | - Jordi Pijuan
- Laboratory of Neurogenetics and Molecular Medicine—IPER, Institut de Recerca Sant Joan de Déu, 08950 Barcelona, Spain;
| | - Judith Armstrong
- Department of Genetic and Molecular Medicine—IPER, Hospital Sant Joan de Déu and Institut de Recerca Sant Joan de Déu, 08950 Barcelona, Spain; (D.Y.); (J.A.); (L.M.); (G.F.); (J.M.); (M.R.)
- Center for Biomedical Research Network on Rare Diseases (CIBERER), ISCIII, 08950 Barcelona, Spain;
| | - Loreto Martorell
- Department of Genetic and Molecular Medicine—IPER, Hospital Sant Joan de Déu and Institut de Recerca Sant Joan de Déu, 08950 Barcelona, Spain; (D.Y.); (J.A.); (L.M.); (G.F.); (J.M.); (M.R.)
- Laboratory of Neurogenetics and Molecular Medicine—IPER, Institut de Recerca Sant Joan de Déu, 08950 Barcelona, Spain;
| | - Guerau Fernàndez
- Department of Genetic and Molecular Medicine—IPER, Hospital Sant Joan de Déu and Institut de Recerca Sant Joan de Déu, 08950 Barcelona, Spain; (D.Y.); (J.A.); (L.M.); (G.F.); (J.M.); (M.R.)
- Center for Biomedical Research Network on Rare Diseases (CIBERER), ISCIII, 08950 Barcelona, Spain;
| | - Joan Maynou
- Department of Genetic and Molecular Medicine—IPER, Hospital Sant Joan de Déu and Institut de Recerca Sant Joan de Déu, 08950 Barcelona, Spain; (D.Y.); (J.A.); (L.M.); (G.F.); (J.M.); (M.R.)
- Center for Biomedical Research Network on Rare Diseases (CIBERER), ISCIII, 08950 Barcelona, Spain;
| | - Cristina Jou
- Department of Pathology, Hospital Sant Joan de Déu, Pediatric Biobank for Research, Institut de Recerca Sant Joan de Déu, 08950 Barcelona, Spain;
| | - Mònica Roldan
- Department of Genetic and Molecular Medicine—IPER, Hospital Sant Joan de Déu and Institut de Recerca Sant Joan de Déu, 08950 Barcelona, Spain; (D.Y.); (J.A.); (L.M.); (G.F.); (J.M.); (M.R.)
- Confocal Microscopy and Cellular Imaging Unit, Institut de Recerca Sant Joan de Déu, 08950 Barcelona, Spain
| | - Carlos Ortez
- Neuromuscular Unit, Department of Pediatric Neurology, Hospital Sant Joan de Déu and Institut de Recerca Sant Joan de Déu, 08950 Barcelona, Spain; (D.N.-d.B.); (C.O.)
- Division of Pediatrics, Clinic Institute of Medicine & Dermatology, Hospital Clínic, University of Barcelona School of Medicine and Health Sciences, 08950 Barcelona, Spain
| | - Andrés Nascimento
- Center for Biomedical Research Network on Rare Diseases (CIBERER), ISCIII, 08950 Barcelona, Spain;
- Neuromuscular Unit, Department of Pediatric Neurology, Hospital Sant Joan de Déu and Institut de Recerca Sant Joan de Déu, 08950 Barcelona, Spain; (D.N.-d.B.); (C.O.)
| | - Janet Hoenicka
- Center for Biomedical Research Network on Rare Diseases (CIBERER), ISCIII, 08950 Barcelona, Spain;
- Laboratory of Neurogenetics and Molecular Medicine—IPER, Institut de Recerca Sant Joan de Déu, 08950 Barcelona, Spain;
| | - Francesc Palau
- Department of Genetic and Molecular Medicine—IPER, Hospital Sant Joan de Déu and Institut de Recerca Sant Joan de Déu, 08950 Barcelona, Spain; (D.Y.); (J.A.); (L.M.); (G.F.); (J.M.); (M.R.)
- Center for Biomedical Research Network on Rare Diseases (CIBERER), ISCIII, 08950 Barcelona, Spain;
- Laboratory of Neurogenetics and Molecular Medicine—IPER, Institut de Recerca Sant Joan de Déu, 08950 Barcelona, Spain;
- Department of Pathology, Hospital Sant Joan de Déu, Pediatric Biobank for Research, Institut de Recerca Sant Joan de Déu, 08950 Barcelona, Spain;
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19
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Boutary S, Echaniz-Laguna A, Adams D, Loisel-Duwattez J, Schumacher M, Massaad C, Massaad-Massade L. Treating PMP22 gene duplication-related Charcot-Marie-Tooth disease: the past, the present and the future. Transl Res 2021; 227:100-111. [PMID: 32693030 DOI: 10.1016/j.trsl.2020.07.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 07/02/2020] [Accepted: 07/15/2020] [Indexed: 12/30/2022]
Abstract
Charcot-Marie-Tooth (CMT) disease is the most frequent inherited neuropathy, affecting 1/1500 to 1/10000. CMT1A represents 60%-70% of all CMT and is caused by a duplication on chromosome 17p11.2 leading to an overexpression of the Peripheral Myelin Protein 22 (PMP22). PMP22 gene is under tight regulation and small changes in its expression influences myelination and affect motor and sensory functions. To date, CMT1A treatment is symptomatic and classic pharmacological options have been disappointing. Here, we review the past, present, and future treatment options for CMT1A, with a special emphasis on the highly promising potential of PMP22-targeted small interfering RNA and antisense oligonucleotides.
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Affiliation(s)
- Suzan Boutary
- U 1195, INSERM and Paris-Saclay University, Le Kremlin-Bicêtre, France
| | - Andoni Echaniz-Laguna
- U 1195, INSERM and Paris-Saclay University, Le Kremlin-Bicêtre, France; Neurology Department, AP-HP, Paris-Saclay Universityand French Referent Center for Familial Amyloid Polyneuropathy and Other Rare Peripheral Neuropathies (CRMR-NNERF), Bicêtre Hospital, Le Kremlin-Bicêtre, France
| | - David Adams
- U 1195, INSERM and Paris-Saclay University, Le Kremlin-Bicêtre, France; Neurology Department, AP-HP, Paris-Saclay Universityand French Referent Center for Familial Amyloid Polyneuropathy and Other Rare Peripheral Neuropathies (CRMR-NNERF), Bicêtre Hospital, Le Kremlin-Bicêtre, France
| | - Julien Loisel-Duwattez
- U 1195, INSERM and Paris-Saclay University, Le Kremlin-Bicêtre, France; Neurology Department, AP-HP, Paris-Saclay Universityand French Referent Center for Familial Amyloid Polyneuropathy and Other Rare Peripheral Neuropathies (CRMR-NNERF), Bicêtre Hospital, Le Kremlin-Bicêtre, France
| | | | - Charbel Massaad
- Faculty of Basic and Biomedical Sciences, Paris Descartes University, INSERM UMRS 1124, Paris, France
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20
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Tariq H, Tariq I, Bourinaris T, Houlden H, Naz S. Some pathogenic SETX variants are partially conserved during evolution. Gene 2020; 771:145360. [PMID: 33333218 DOI: 10.1016/j.gene.2020.145360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 11/28/2020] [Accepted: 12/01/2020] [Indexed: 10/22/2022]
Abstract
Variants in SETX have been implicated in recessively and dominantly inherited disorders, ataxia with oculomotor apraxia type 2 (AOA2 OMIM# 606002) and amyotrophic lateral sclerosis (ALS4, OMIM# 602433) respectively, in humans. We report two novel bi-allelic pathogenic variants in SETX in patients suffering from ataxia with oculomotor apraxia type 2, extending the allelic spectrum of the gene variants. We also discuss the pathogenicity of SETX variants in relation to the evolutionary conservation status of the affected amino acids. Our analyses suggest that variants of some amino acids which are not fully conserved in evolution, may cause a disorder in humans, provided the particular pathogenic variant is absent in other orthologues.
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Affiliation(s)
- Huma Tariq
- Department of Neurogenetics, UCL Institute of Neurology, Queen Square House, University College London, London, United Kingdom; School of Biological Sciences, University of the Punjab, Lahore, Pakistan.
| | - Iqra Tariq
- Khawaja Muhammad Safdar Medical College, Sialkot, Pakistan
| | - Thomas Bourinaris
- Department of Neurogenetics, UCL Institute of Neurology, Queen Square House, University College London, London, United Kingdom
| | - Henry Houlden
- Department of Neurogenetics, UCL Institute of Neurology, Queen Square House, University College London, London, United Kingdom.
| | - Sadaf Naz
- School of Biological Sciences, University of the Punjab, Lahore, Pakistan.
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21
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Kanzi AM, San JE, Chimukangara B, Wilkinson E, Fish M, Ramsuran V, de Oliveira T. Next Generation Sequencing and Bioinformatics Analysis of Family Genetic Inheritance. Front Genet 2020; 11:544162. [PMID: 33193618 PMCID: PMC7649788 DOI: 10.3389/fgene.2020.544162] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 09/21/2020] [Indexed: 12/29/2022] Open
Abstract
Mendelian and complex genetic trait diseases continue to burden and affect society both socially and economically. The lack of effective tests has hampered diagnosis thus, the affected lack proper prognosis. Mendelian diseases are caused by genetic mutations in a singular gene while complex trait diseases are caused by the accumulation of mutations in either linked or unlinked genomic regions. Significant advances have been made in identifying novel diseases associated mutations especially with the introduction of next generation and third generation sequencing. Regardless, some diseases are still without diagnosis as most tests rely on SNP genotyping panels developed from population based genetic analyses. Analysis of family genetic inheritance using whole genomes, whole exomes or a panel of genes has been shown to be effective in identifying disease-causing mutations. In this review, we discuss next generation and third generation sequencing platforms, bioinformatic tools and genetic resources commonly used to analyze family based genomic data with a focus on identifying inherited or novel disease-causing mutations. Additionally, we also highlight the analytical, ethical and regulatory challenges associated with analyzing personal genomes which constitute the data used for family genetic inheritance.
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Affiliation(s)
- Aquillah M. Kanzi
- Kwazulu-Natal Research and Innovation Sequencing Platform (KRISP), School of Laboratory Medicine and Medical Sciences, College of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
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22
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Mul K, Schouten MI, van der Looij E, Dooijes D, Hennekam FAM, Notermans NC, Praamstra P, van Gaalen J, Kamsteeg EJ, Verbeek NE, van de Warrenburg BPC. A hereditary spastic paraplegia predominant phenotype caused by variants in the NEFL gene. Parkinsonism Relat Disord 2020; 80:98-101. [PMID: 32979786 DOI: 10.1016/j.parkreldis.2020.09.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 09/07/2020] [Accepted: 09/08/2020] [Indexed: 11/28/2022]
Abstract
INTRODUCTION This study reports a large series of patients with a clinical picture dominated by spastic paraplegia in whom variants in the NEFL gene, a known cause for Charcot-Marie-Tooth disease, were identified. METHODS Index patients referred for a suspicion of hereditary spastic paraplegia (HSP) were clinically assessed and genetic analysis by next-generation sequencing was undertaken. Additional family members were clinically examined and subjected to targeted testing. RESULTS We identified two different heterozygous dominant variants in the NEFL gene in 25 patients from 14 families. Most of them (21/25) had a clinical diagnosis of HSP, often with a concomitant clinical diagnosis of polyneuropathy (16/21). Two patients were identified with a polyneuropathy with a pyramidal reflex pattern, but without spasticity. Two patients had isolated polyneuropathy. Out of the 21 patients with a diagnosis of HSP, two had co-occurring cerebellar signs. The c.262A > C p.(Thr88Pro) variant was detected in 13 families. Genealogical analysis showed shared ancestors or a similar geographical origin in 12, suggesting a founder effect. The other variant, c.296A > C p.(Asp99Ala), was found in only one family, in which limited segregation analysis could be performed. DISCUSSION Variants in the NEFL gene can cause HSP, with or without co-existing polyneuropathy, and should be included in diagnostic testing strategies for HSP patients.
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Affiliation(s)
- Karlien Mul
- Department of Neurology, Radboud University Medical Center, Nijmegen, the Netherlands.
| | - Meyke I Schouten
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands.
| | - Erica van der Looij
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands.
| | - Dennis Dooijes
- Department of Genetics, Utrecht University Medical Center, Utrecht, the Netherlands.
| | - Frederic A M Hennekam
- Department of Genetics, Utrecht University Medical Center, Utrecht, the Netherlands.
| | - Nicolette C Notermans
- Department of Neurology, Utrecht University Medical Center, Utrecht, the Netherlands.
| | - Peter Praamstra
- Department of Neurology, Radboud University Medical Center, Nijmegen, the Netherlands.
| | - Judith van Gaalen
- Department of Neurology, Radboud University Medical Center, Nijmegen, the Netherlands.
| | - Erik-Jan Kamsteeg
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands.
| | - Nienke E Verbeek
- Department of Genetics, Utrecht University Medical Center, Utrecht, the Netherlands.
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23
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Zhong M, Luo Q, Ye T, Zhu X, Chen X, Liu J. Identification of Candidate Genes Associated with Charcot-Marie-Tooth Disease by Network and Pathway Analysis. BIOMED RESEARCH INTERNATIONAL 2020; 2020:1353516. [PMID: 33029488 PMCID: PMC7532371 DOI: 10.1155/2020/1353516] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 07/21/2020] [Accepted: 08/12/2020] [Indexed: 12/15/2022]
Abstract
Charcot-Marie-Tooth Disease (CMT) is the most common clinical genetic disease of the peripheral nervous system. Although many studies have focused on elucidating the pathogenesis of CMT, few focuses on achieving a systematic analysis of biology to decode the underlying pathological molecular mechanisms and the mechanism of its disease remains to be elucidated. So our study may provide further useful insights into the molecular mechanisms of CMT based on a systematic bioinformatics analysis. In the current study, by reviewing the literatures deposited in PUBMED, we identified 100 genes genetically related to CMT. Then, the functional features of the CMT-related genes were examined by R software and KOBAS, and the selected biological process crosstalk was visualized with the software Cytoscape. Moreover, CMT specific molecular network analysis was conducted by the Molecular Complex Detection (MCODE) Algorithm. The biological function enrichment analysis suggested that myelin sheath, axon, peripheral nervous system, mitochondrial function, various metabolic processes, and autophagy played important roles in CMT development. Aminoacyl-tRNA biosynthesis, metabolic pathways, and vasopressin-regulated water reabsorption were significantly enriched in the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway network, suggesting that these pathways may play key roles in CMT occurrence and development. According to the crosstalk, the biological processes could be roughly divided into a correlative module and two separate modules. MCODE clusters showed that in top 3 clusters, 13 of CMT-related genes were included in the network and 30 candidate genes were discovered which might be potentially related to CMT. The study may help to update the new understanding of the pathogenesis of CMT and expand the potential genes of CMT for further exploration.
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Affiliation(s)
- Min Zhong
- Department of Laboratory Medicine, The Affiliated Hospital of Southwest Medical University, 25 Taiping Street, Luzhou, 646000 Sichuan, China
| | - Qing Luo
- Department of Laboratory Medicine, The Affiliated Hospital of Southwest Medical University, 25 Taiping Street, Luzhou, 646000 Sichuan, China
| | - Ting Ye
- Department of Laboratory Medicine, The Affiliated Hospital of Southwest Medical University, 25 Taiping Street, Luzhou, 646000 Sichuan, China
| | - XiDan Zhu
- Department of Laboratory Medicine, The Affiliated Hospital of Southwest Medical University, 25 Taiping Street, Luzhou, 646000 Sichuan, China
| | - Xiu Chen
- Department of Neurology, The Affiliated Hospital of Southwest Medical University, 25 Taiping Street, Luzhou, 646000 Sichuan, China
| | - JinBo Liu
- Department of Laboratory Medicine, The Affiliated Hospital of Southwest Medical University, 25 Taiping Street, Luzhou, 646000 Sichuan, China
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24
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Guillaud L, El-Agamy SE, Otsuki M, Terenzio M. Anterograde Axonal Transport in Neuronal Homeostasis and Disease. Front Mol Neurosci 2020; 13:556175. [PMID: 33071754 PMCID: PMC7531239 DOI: 10.3389/fnmol.2020.556175] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 08/26/2020] [Indexed: 12/12/2022] Open
Abstract
Neurons are highly polarized cells with an elongated axon that extends far away from the cell body. To maintain their homeostasis, neurons rely extensively on axonal transport of membranous organelles and other molecular complexes. Axonal transport allows for spatio-temporal activation and modulation of numerous molecular cascades, thus playing a central role in the establishment of neuronal polarity, axonal growth and stabilization, and synapses formation. Anterograde and retrograde axonal transport are supported by various molecular motors, such as kinesins and dynein, and a complex microtubule network. In this review article, we will primarily discuss the molecular mechanisms underlying anterograde axonal transport and its role in neuronal development and maturation, including the establishment of functional synaptic connections. We will then provide an overview of the molecular and cellular perturbations that affect axonal transport and are often associated with axonal degeneration. Lastly, we will relate our current understanding of the role of axonal trafficking concerning anterograde trafficking of mRNA and its involvement in the maintenance of the axonal compartment and disease.
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Affiliation(s)
- Laurent Guillaud
- Molecular Neuroscience Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
| | - Sara Emad El-Agamy
- Molecular Neuroscience Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
| | - Miki Otsuki
- Molecular Neuroscience Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
| | - Marco Terenzio
- Molecular Neuroscience Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
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25
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The Zinc-Finger Domain Containing Protein ZC4H2 Interacts with TRPV4, Enhancing Channel Activity and Turnover at the Plasma Membrane. Int J Mol Sci 2020; 21:ijms21103556. [PMID: 32443528 PMCID: PMC7278933 DOI: 10.3390/ijms21103556] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 05/14/2020] [Accepted: 05/15/2020] [Indexed: 02/07/2023] Open
Abstract
The Ca2+-permeable Transient Receptor Potential channel vanilloid subfamily member 4 (TRPV4) is involved in a broad range of physiological processes, including the regulation of systemic osmotic pressure, bone resorption, vascular tone, and bladder function. Mutations in the TRPV4 gene are the cause of a spectrum of inherited diseases (or TRPV4-pathies), which include skeletal dysplasias, arthropathies, and neuropathies. There is little understanding of the pathophysiological mechanisms underlying these variable disease phenotypes, but it has been hypothesized that disease-causing mutations affect interaction with regulatory proteins. Here, we performed a mammalian protein-protein interaction trap (MAPPIT) screen to identify proteins that interact with the cytosolic N terminus of human TRPV4, a region containing the majority of disease-causing mutations. We discovered the zinc-finger domain-containing protein ZC4H2 as a TRPV4-interacting protein. In heterologous expression experiments, we found that ZC4H2 increases both the basal activity of human TRPV4 as well as Ca2+ responses evoked by ligands or hypotonic cell swelling. Using total internal reflection fluorescence (TIRF) microscopy, we further showed that ZC4H2 accelerates TRPV4 turnover at the plasma membrane. Overall, these data demonstrate that ZC4H2 is a positive modulator of TRPV4, and suggest a link between TRPV4 and ZC4H2-associated rare disorders, which have several neuromuscular symptoms in common with TRPV4-pathies.
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26
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Abstract
PURPOSE OF REVIEW Charcot-Marie-Tooth (CMT) disease and related disorders are the commonest group of inherited neuromuscular diseases and represent a heterogeneous group of disorders. This review will cover recent advances in genetic diagnosis and the evolving genetic and phenotype landscape of this disease group. We will review recent evidence of the increasingly recognized phenotypic overlap with other neurodegenerative conditions including hereditary spastic paraplegia, hereditary ataxias and mitochondrial diseases and highlight the importance of deep phenotyping to inform genetic diagnosis and prognosis. RECENT FINDINGS Through whole exome sequencing and multicentre collaboration new genes are being identified as causal for CMT expanding the genetic heterogeneity of this condition. In addition, an increasing number of variants have been identified in genes known to cause complex inherited diseases in which the peripheral neuropathy is part of the disorder and may be the presenting feature. The recent discovery of a repeat expansion in the RFC1 gene in cerebellar ataxia, neuropathy, vestibular areflexia syndrome highlights the prevalence of late-onset recessive conditions which have historically been considered to cause early-onset disease. SUMMARY CMT is an evolving field with considerable phenotypic and genetic heterogeneity and deep phenotyping remains a cornerstone in contemporary CMT diagnostics.
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27
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Beijer D, Sisto A, Van Lent J, Baets J, Timmerman V. Defects in Axonal Transport in Inherited Neuropathies. J Neuromuscul Dis 2020; 6:401-419. [PMID: 31561383 PMCID: PMC6918914 DOI: 10.3233/jnd-190427] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Axonal transport is a highly complex process essential for sustaining proper neuronal functioning. Disturbances can result in an altered neuronal homeostasis, aggregation of cargoes, and ultimately a dying-back degeneration of neurons. The impact of dysfunction in axonal transport is shown by genetic defects in key proteins causing a broad spectrum of neurodegenerative diseases, including inherited peripheral neuropathies. In this review, we provide an overview of the cytoskeletal components, molecular motors and adaptor proteins involved in axonal transport mechanisms and their implication in neuronal functioning. In addition, we discuss the involvement of axonal transport dysfunction in neurodegenerative diseases with a particular focus on inherited peripheral neuropathies. Lastly, we address some recent scientific advances most notably in therapeutic strategies employed in the area of axonal transport, patient-derived iPSC models, in vivo animal models, antisense-oligonucleotide treatments, and novel chemical compounds.
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Affiliation(s)
- Danique Beijer
- Neurogenetics Research Group, Department of Medical Sciences, University of Antwerp, Antwerpen, Belgium.,Neurogenetics Laboratory, Institute Born Bunge, Antwerpen, Belgium
| | - Angela Sisto
- Peripheral Neuropathy Research Group, Department of Biomedical Sciences, University of Antwerp, Antwerpen, Belgium.,Neurogenetics Laboratory, Institute Born Bunge, Antwerpen, Belgium
| | - Jonas Van Lent
- Peripheral Neuropathy Research Group, Department of Biomedical Sciences, University of Antwerp, Antwerpen, Belgium.,Neurogenetics Laboratory, Institute Born Bunge, Antwerpen, Belgium
| | - Jonathan Baets
- Neurogenetics Research Group, Department of Medical Sciences, University of Antwerp, Antwerpen, Belgium.,Neurogenetics Laboratory, Institute Born Bunge, Antwerpen, Belgium.,Neurology Department, University Hospital Antwerp, Antwerpen, Belgium
| | - Vincent Timmerman
- Peripheral Neuropathy Research Group, Department of Biomedical Sciences, University of Antwerp, Antwerpen, Belgium.,Neurogenetics Laboratory, Institute Born Bunge, Antwerpen, Belgium
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28
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Koboldt DC, Waldrop MA, Wilson RK, Flanigan KM. The Genotypic and Phenotypic Spectrum of
BICD2
Variants in Spinal Muscular Atrophy. Ann Neurol 2020; 87:487-496. [DOI: 10.1002/ana.25704] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 02/12/2020] [Accepted: 02/12/2020] [Indexed: 12/18/2022]
Affiliation(s)
- Daniel C. Koboldt
- Institute for Genomic Medicine Nationwide Children's Hospital Columbus OH
- Department of Pediatrics Ohio State University Columbus OH
| | - Megan A. Waldrop
- Department of Pediatrics Ohio State University Columbus OH
- Center for Gene Therapy Nationwide Children's Hospital Columbus OH
- Department of Neurology Ohio State University Columbus OH
| | - Richard K. Wilson
- Institute for Genomic Medicine Nationwide Children's Hospital Columbus OH
- Department of Pediatrics Ohio State University Columbus OH
| | - Kevin M. Flanigan
- Department of Pediatrics Ohio State University Columbus OH
- Center for Gene Therapy Nationwide Children's Hospital Columbus OH
- Department of Neurology Ohio State University Columbus OH
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29
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Song GJ, Gupta DP, Rahman MH, Park HT, Al Ghouleh I, Bisello A, Lee MG, Park JY, Park HH, Jun JH, Chung KW, Choi BO, Suk K. Loss-of-function of EBP50 is a new cause of hereditary peripheral neuropathy: EBP50 functions in peripheral nerve system. Glia 2020; 68:1794-1809. [PMID: 32077526 DOI: 10.1002/glia.23805] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 02/04/2020] [Accepted: 02/07/2020] [Indexed: 12/12/2022]
Abstract
Finding causative genetic mutations is important in the diagnosis and treatment of hereditary peripheral neuropathies. This study was conducted to find new genes involved in the pathophysiology of hereditary peripheral neuropathy. We identified a new mutation in the EBP50 gene, which is co-segregated with neuropathic phenotypes, including motor and sensory deficit in a family with Charcot-Marie-Tooth disease. EBP50 is known to be important for the formation of microvilli in epithelial cells, and the discovery of this gene mutation allowed us to study the function of EBP50 in the nervous system. EBP50 was strongly expressed in the nodal and paranodal regions of sciatic nerve fibers, where Schwann cell microvilli contact the axolemma, and at the growth tips of primary Schwann cells. In addition, EBP50 expression was decreased in mouse models of peripheral neuropathy. Knockout mice were used to study EBP50 function in the peripheral nervous system. Interestingly motor function deficit and abnormal histology of nerve fibers were observed in EBP50+/- heterozygous mice at 12 months of age, but not 3 months. in vitro studies using Schwann cells showed that NRG1-induced AKT activation and migration were significantly reduced in cells overexpressing the I325V mutant of EBP50 or cells with knocked-down EBP50 expression. In conclusion, we show for the first time that loss of function due to EBP50 gene deficiency or mutation can cause peripheral neuropathy.
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Affiliation(s)
- Gyun Jee Song
- Department of Medical Science, Institute for Bio-Medical Convergence, Catholic Kwandong University, International St. Mary's Hospital, Incheon, Republic of Korea
| | - Deepak Prasad Gupta
- Department of Pharmacology, Brain Science and Engineering Institute, BK21 Plus KNU Biomedical Convergence Program, School of Medicine, Kyungpook National University, Daegu, Republic of Korea
| | - Md Habibur Rahman
- Department of Pharmacology, Brain Science and Engineering Institute, BK21 Plus KNU Biomedical Convergence Program, School of Medicine, Kyungpook National University, Daegu, Republic of Korea
| | - Hwan Tae Park
- Department of Molecular Neuroscience, College of Medicine, Dong-A University, Busan, Republic of Korea
| | - Imad Al Ghouleh
- Division of Cardiology, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Alessandro Bisello
- Department of Pharmacology and Chemical Biology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
| | - Maan-Gee Lee
- Department of Pharmacology, Brain Science and Engineering Institute, BK21 Plus KNU Biomedical Convergence Program, School of Medicine, Kyungpook National University, Daegu, Republic of Korea
| | - Jae-Yong Park
- School of Biosystems and Biomedical Sciences, College of Health Sciences, Korea University, Seoul, Republic of Korea
| | - Hyun Ho Park
- College of Pharmacy, Chung-Ang University, Seoul, Republic of Korea
| | - Jin Hyun Jun
- Department of Senior Healthcare, BK21 Plus Program, Graduate School of Eulji University, Department of Biomedical Laboratory Science, College of Health Science, Eulji University, Seongnam, Republic of Korea
| | - Ki Wha Chung
- Department of Biological Sciences, Kongju National University, Gongju, Republic of Korea
| | - Byung-Ok Choi
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Kyoungho Suk
- Department of Pharmacology, Brain Science and Engineering Institute, BK21 Plus KNU Biomedical Convergence Program, School of Medicine, Kyungpook National University, Daegu, Republic of Korea
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30
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A de novo EGR2 variant, c.1232A > G p.Asp411Gly, causes severe early-onset Charcot-Marie-Tooth Neuropathy Type 3 (Dejerine-Sottas Neuropathy). Sci Rep 2019; 9:19336. [PMID: 31852952 PMCID: PMC6920433 DOI: 10.1038/s41598-019-55875-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Accepted: 12/03/2019] [Indexed: 01/04/2023] Open
Abstract
EGR2 (early growth response 2) is a crucial transcription factor for the myelination of the peripheral nervous system. Mutations in EGR2 are reported to cause a heterogenous spectrum of peripheral neuropathy with wide variation in both severity and age of onset, including demyelinating and axonal forms of Charcot-Marie Tooth (CMT) neuropathy, Dejerine-Sottas neuropathy (DSN/CMT3), and congenital hypomyelinating neuropathy (CHN/CMT4E). Here we report a sporadic de novo EGR2 variant, c.1232A > G (NM_000399.5), causing a missense p.Asp411Gly substitution and discovered through whole-exome sequencing (WES) of the proband. The resultant phenotype is severe demyelinating DSN with onset at two years of age, confirmed through nerve biopsy and electrophysiological examination. In silico analyses showed that the Asp411 residue is evolutionarily conserved, and the p.Asp411Gly variant was predicted to be deleterious by multiple in silico analyses. A luciferase-based reporter assay confirmed the reduced ability of p.Asp411Gly EGR2 to activate a PMP22 (peripheral myelin protein 22) enhancer element compared to wild-type EGR2. This study adds further support to the heterogeneity of EGR2-related peripheral neuropathies and provides strong functional evidence for the pathogenicity of the p.Asp411Gly EGR2 variant.
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31
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Cortese A, Wilcox JE, Polke JM, Poh R, Skorupinska M, Rossor AM, Laura M, Tomaselli PJ, Houlden H, Shy ME, Reilly MM. Targeted next-generation sequencing panels in the diagnosis of Charcot-Marie-Tooth disease. Neurology 2019; 94:e51-e61. [PMID: 31827005 PMCID: PMC7011687 DOI: 10.1212/wnl.0000000000008672] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 06/24/2019] [Indexed: 12/22/2022] Open
Abstract
OBJECTIVE To investigate the effectiveness of targeted next-generation sequencing (NGS) panels in achieving a molecular diagnosis in Charcot-Marie-Tooth disease (CMT) and related disorders in a clinical setting. METHODS We prospectively enrolled 220 patients from 2 tertiary referral centers, one in London, United Kingdom (n = 120), and one in Iowa (n = 100), in whom a targeted CMT NGS panel had been requested as a diagnostic test. PMP22 duplication/deletion was previously excluded in demyelinating cases. We reviewed the genetic and clinical data upon completion of the diagnostic process. RESULTS After targeted NGS sequencing, a definite molecular diagnosis, defined as a pathogenic or likely pathogenic variant, was reached in 30% of cases (n = 67). The diagnostic rate was similar in London (32%) and Iowa (29%). Variants of unknown significance were found in an additional 33% of cases. Mutations in GJB1, MFN2, and MPZ accounted for 39% of cases that received genetic confirmation, while the remainder of positive cases had mutations in diverse genes, including SH3TC2, GDAP1, IGHMBP2, LRSAM1, FDG4, and GARS, and another 12 less common genes. Copy number changes in PMP22, MPZ, MFN2, SH3TC2, and FDG4 were also accurately detected. A definite genetic diagnosis was more likely in cases with an early onset, a positive family history of neuropathy or consanguinity, and a demyelinating neuropathy. CONCLUSIONS NGS panels are effective tools in the diagnosis of CMT, leading to genetic confirmation in one-third of cases negative for PMP22 duplication/deletion, thus highlighting how rarer and previously undiagnosed subtypes represent a relevant part of the genetic landscape of CMT.
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Affiliation(s)
- Andrea Cortese
- From the MRC Centre for Neuromuscular Diseases (A.C., J.M.P., R.P., M.S., A.M.R., M.L., P.J.T., H.H., M.M.R.), Department of Neuromuscular Diseases, National Hospital for Neurology and Neurosurgery, UCL Queen Square Institute of Neurology, London, UK; Department of Brain and Behavioral Sciences (A.C.), University of Pavia, Italy; and the Department of Neurology (J.E.W., M.E.S.), University of Iowa Carver College of Medicine, Iowa City
| | - Janel E Wilcox
- From the MRC Centre for Neuromuscular Diseases (A.C., J.M.P., R.P., M.S., A.M.R., M.L., P.J.T., H.H., M.M.R.), Department of Neuromuscular Diseases, National Hospital for Neurology and Neurosurgery, UCL Queen Square Institute of Neurology, London, UK; Department of Brain and Behavioral Sciences (A.C.), University of Pavia, Italy; and the Department of Neurology (J.E.W., M.E.S.), University of Iowa Carver College of Medicine, Iowa City
| | - James M Polke
- From the MRC Centre for Neuromuscular Diseases (A.C., J.M.P., R.P., M.S., A.M.R., M.L., P.J.T., H.H., M.M.R.), Department of Neuromuscular Diseases, National Hospital for Neurology and Neurosurgery, UCL Queen Square Institute of Neurology, London, UK; Department of Brain and Behavioral Sciences (A.C.), University of Pavia, Italy; and the Department of Neurology (J.E.W., M.E.S.), University of Iowa Carver College of Medicine, Iowa City
| | - Roy Poh
- From the MRC Centre for Neuromuscular Diseases (A.C., J.M.P., R.P., M.S., A.M.R., M.L., P.J.T., H.H., M.M.R.), Department of Neuromuscular Diseases, National Hospital for Neurology and Neurosurgery, UCL Queen Square Institute of Neurology, London, UK; Department of Brain and Behavioral Sciences (A.C.), University of Pavia, Italy; and the Department of Neurology (J.E.W., M.E.S.), University of Iowa Carver College of Medicine, Iowa City
| | - Mariola Skorupinska
- From the MRC Centre for Neuromuscular Diseases (A.C., J.M.P., R.P., M.S., A.M.R., M.L., P.J.T., H.H., M.M.R.), Department of Neuromuscular Diseases, National Hospital for Neurology and Neurosurgery, UCL Queen Square Institute of Neurology, London, UK; Department of Brain and Behavioral Sciences (A.C.), University of Pavia, Italy; and the Department of Neurology (J.E.W., M.E.S.), University of Iowa Carver College of Medicine, Iowa City
| | - Alexander M Rossor
- From the MRC Centre for Neuromuscular Diseases (A.C., J.M.P., R.P., M.S., A.M.R., M.L., P.J.T., H.H., M.M.R.), Department of Neuromuscular Diseases, National Hospital for Neurology and Neurosurgery, UCL Queen Square Institute of Neurology, London, UK; Department of Brain and Behavioral Sciences (A.C.), University of Pavia, Italy; and the Department of Neurology (J.E.W., M.E.S.), University of Iowa Carver College of Medicine, Iowa City
| | - Matilde Laura
- From the MRC Centre for Neuromuscular Diseases (A.C., J.M.P., R.P., M.S., A.M.R., M.L., P.J.T., H.H., M.M.R.), Department of Neuromuscular Diseases, National Hospital for Neurology and Neurosurgery, UCL Queen Square Institute of Neurology, London, UK; Department of Brain and Behavioral Sciences (A.C.), University of Pavia, Italy; and the Department of Neurology (J.E.W., M.E.S.), University of Iowa Carver College of Medicine, Iowa City
| | - Pedro J Tomaselli
- From the MRC Centre for Neuromuscular Diseases (A.C., J.M.P., R.P., M.S., A.M.R., M.L., P.J.T., H.H., M.M.R.), Department of Neuromuscular Diseases, National Hospital for Neurology and Neurosurgery, UCL Queen Square Institute of Neurology, London, UK; Department of Brain and Behavioral Sciences (A.C.), University of Pavia, Italy; and the Department of Neurology (J.E.W., M.E.S.), University of Iowa Carver College of Medicine, Iowa City
| | - Henry Houlden
- From the MRC Centre for Neuromuscular Diseases (A.C., J.M.P., R.P., M.S., A.M.R., M.L., P.J.T., H.H., M.M.R.), Department of Neuromuscular Diseases, National Hospital for Neurology and Neurosurgery, UCL Queen Square Institute of Neurology, London, UK; Department of Brain and Behavioral Sciences (A.C.), University of Pavia, Italy; and the Department of Neurology (J.E.W., M.E.S.), University of Iowa Carver College of Medicine, Iowa City
| | - Michael E Shy
- From the MRC Centre for Neuromuscular Diseases (A.C., J.M.P., R.P., M.S., A.M.R., M.L., P.J.T., H.H., M.M.R.), Department of Neuromuscular Diseases, National Hospital for Neurology and Neurosurgery, UCL Queen Square Institute of Neurology, London, UK; Department of Brain and Behavioral Sciences (A.C.), University of Pavia, Italy; and the Department of Neurology (J.E.W., M.E.S.), University of Iowa Carver College of Medicine, Iowa City
| | - Mary M Reilly
- From the MRC Centre for Neuromuscular Diseases (A.C., J.M.P., R.P., M.S., A.M.R., M.L., P.J.T., H.H., M.M.R.), Department of Neuromuscular Diseases, National Hospital for Neurology and Neurosurgery, UCL Queen Square Institute of Neurology, London, UK; Department of Brain and Behavioral Sciences (A.C.), University of Pavia, Italy; and the Department of Neurology (J.E.W., M.E.S.), University of Iowa Carver College of Medicine, Iowa City.
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Stone EJ, Uchida A, Brown A. Charcot-Marie-Tooth disease Type 2E/1F mutant neurofilament proteins assemble into neurofilaments. Cytoskeleton (Hoboken) 2019; 76:423-439. [PMID: 31574566 DOI: 10.1002/cm.21566] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 08/30/2019] [Accepted: 09/13/2019] [Indexed: 11/12/2022]
Abstract
Charcot-Marie-Tooth disease Type 2E/1F (CMT2E/1F) is a peripheral neuropathy caused by mutations in neurofilament protein L (NFL), which is one of five neurofilament subunit proteins that co-assemble to form neurofilaments in vivo. Prior studies on cultured cells have shown that CMT2E/1F mutations disrupt neurofilament assembly and lead to protein aggregation, suggesting a possible disease mechanism. However, electron microscopy of axons in peripheral nerve biopsies from patients has revealed accumulations of neurofilament polymers of normal appearance and no evidence of protein aggregates. To reconcile these observations, we reexamined the assembly of seven CMT2E/1F NFL mutants in cultured cells. None of the mutants assembled into homopolymers in SW13vim- cells, but P8R, P22S, L268/269P, and P440/441L mutant NFL assembled into heteropolymers in the presence of neurofilament protein M (NFM) alone, and N98S, Q332/333P, and E396/397K mutant NFL assembled in the presence of NFM and peripherin. P8R, P22S, N98S, L268/269P, E396/397K, and P440/441L mutant NFL co-assembled into neurofilaments with endogenous NFL, NFM, and α-internexin in cultured neurons, although the N98S and E396/397K mutants showed reduced filament incorporation, and the Q332/333P mutant showed limited incorporation. We conclude that all the mutants are capable of assembling into neurofilaments, but for some of the mutants this was dependent on the identity of the other neurofilament proteins available for co-assembly, and most likely also their relative expression level. Thus, caution should be exercised when drawing conclusions about the assembly capacity of CMT2E/1F mutants based on transient transfections in cultured cells.
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Affiliation(s)
- Elizabeth J Stone
- Department of Neuroscience, Ohio State University, Columbus, Ohio.,Neuroscience Graduate Program, Ohio State University, Columbus, Ohio
| | - Atsuko Uchida
- Department of Neuroscience, Ohio State University, Columbus, Ohio
| | - Anthony Brown
- Department of Neuroscience, Ohio State University, Columbus, Ohio
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Next-generation sequencing in Charcot-Marie-Tooth disease: opportunities and challenges. Nat Rev Neurol 2019; 15:644-656. [PMID: 31582811 DOI: 10.1038/s41582-019-0254-5] [Citation(s) in RCA: 120] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/12/2019] [Indexed: 01/08/2023]
Abstract
Charcot-Marie-Tooth disease and the related disorders hereditary motor neuropathy and hereditary sensory neuropathy, collectively termed CMT, are the commonest group of inherited neuromuscular diseases, and they exhibit wide phenotypic and genetic heterogeneity. CMT is usually characterized by distal muscle atrophy, often with foot deformity, weakness and sensory loss. In the past decade, next-generation sequencing (NGS) technologies have revolutionized genomic medicine and, as these technologies are being applied to clinical practice, they are changing our diagnostic approach to CMT. In this Review, we discuss the application of NGS technologies, including disease-specific gene panels, whole-exome sequencing, whole-genome sequencing (WGS), mitochondrial sequencing and high-throughput transcriptome sequencing, to the diagnosis of CMT. We discuss the growing challenge of variant interpretation and consider how the clinical phenotype can be combined with genetic, bioinformatic and functional evidence to assess the pathogenicity of genetic variants in patients with CMT. WGS has several advantages over the other techniques that we discuss, which include unparalleled coverage of coding, non-coding and intergenic areas of both nuclear and mitochondrial genomes, the ability to identify structural variants and the opportunity to perform genome-wide dense homozygosity mapping. We propose an algorithm for incorporating WGS into the CMT diagnostic pathway.
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34
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The first Portuguese family with NEFL-related Charcot-Marie-Tooth type 2 disease. ACTA MYOLOGICA : MYOPATHIES AND CARDIOMYOPATHIES : OFFICIAL JOURNAL OF THE MEDITERRANEAN SOCIETY OF MYOLOGY 2019; 38:180-183. [PMID: 31788662 PMCID: PMC6859411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 10/29/2022]
Abstract
CMT disease caused by NEFL gene mutations is rare. The mode of inheritance can be dominant or recessive and nerve conduction velocities can be normal, reduced (demyelinating) or presenting intermediate values. Two Portuguese adult related members in two successive generations were affected by peripheral neuropathy, one with a chronic ataxic peripheral neuropathy and the other with a classical Charcot-Marie-Tooth phenotype. An axonal sensorimotor peripheral neuropathy was described at neurophysiology. A missense heterozygous mutation, c.794A > G (p.Tyr265Cys), in the NEFL gene was found in both patients. This is the first Portuguese family reported with NEFL-related CMT type 2.
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35
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Deng S, Feely SME, Shi Y, Zhai H, Zhan L, Siddique T, Deng HX, Shy ME. Incidence and Clinical Features of TRPV4-Linked Axonal Neuropathies in a USA Cohort of Charcot-Marie-Tooth Disease Type 2. Neuromolecular Med 2019; 22:68-72. [PMID: 31468327 DOI: 10.1007/s12017-019-08564-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 08/20/2019] [Indexed: 11/25/2022]
Abstract
Mutations in TRPV4 are linked to a group of clinically distinct, but also overlapping axonal neuropathies, including Charcot-Marie-Tooth disease type 2C (CMT2C), scapuloperoneal spinal muscular atrophy, and congenital distal spinal muscular atrophy. The incidence of TRPV4-linked cases ranges from 0 to 7% in overall axonal neuropathy cohorts from European countries and Australia. However, the data from other areas remain largely unknown. In this study, we screened for TRPV4 mutations in a well-characterized USA cohort of 62 unrelated CMT2 patients without mutations in MFN2, GARS, NEFL, and GDAP1. All 15 coding exons of TRPV4 were analyzed by Sanger-sequencing. Clinical features of TRPV4-linked patients were compared with those lacking TRPV4 mutations. We identified two TRPV4 mutations in two patients. A TRPV4-R316C was identified in a patient with family history, while a TRPV4-R269C in an apparently sporadic case. Marked clinical variations were observed in the patients with TRPV4 mutations. Our data suggest that TRPV4-linked CMT2C accounts for a sizable fraction in this USA cohort of CMT2; it has a wide phenotypic spectrum, and vocal cord paralysis, scapular weakness and wasting, skeletal dysplasia, and hearing loss are suggestive signs for TRPV4-linked CMT2C.
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Affiliation(s)
- Sheng Deng
- The Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
- Department of Pharmacy, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Shawna M E Feely
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Yong Shi
- The Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Hong Zhai
- The Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Luna Zhan
- The Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Teepu Siddique
- The Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Han-Xiang Deng
- The Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
- The Ken and Ruth Davee Department of Neurology and Clinical Neurosciences, Northwestern University Feinberg School of Medicine, Tarry Building, Room 13-715, 303 East Chicago Avenue, Chicago, IL, 60611, USA.
| | - Michael E Shy
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA.
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Linkage analysis and whole exome sequencing reveals AHNAK2 as a novel genetic cause for autosomal recessive CMT in a Malaysian family. Neurogenetics 2019; 20:117-127. [DOI: 10.1007/s10048-019-00576-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 04/03/2019] [Indexed: 10/27/2022]
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37
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Elert-Dobkowska E, Stepniak I, Krysa W, Ziora-Jakutowicz K, Rakowicz M, Sobanska A, Pilch J, Antczak-Marach D, Zaremba J, Sulek A. Next-generation sequencing study reveals the broader variant spectrum of hereditary spastic paraplegia and related phenotypes. Neurogenetics 2019; 20:27-38. [PMID: 30778698 PMCID: PMC6411833 DOI: 10.1007/s10048-019-00565-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Accepted: 01/11/2019] [Indexed: 12/18/2022]
Abstract
Hereditary spastic paraplegias (HSPs) are clinically and genetically heterogeneous neurodegenerative disorders. Numerous genes linked to HSPs, overlapping phenotypes between HSP subtypes and other neurodegenerative disorders and the HSPs’ dual mode of inheritance (both dominant and recessive) make the genetic diagnosis of HSPs complex and difficult. Out of the original HSP cohort comprising 306 index cases (familial and isolated) who had been tested according to “traditional workflow/guidelines” by Multiplex Ligation-dependent Probe Amplification (MLPA) and Sanger sequencing, 30 unrelated patients (all familial cases) with unsolved genetic diagnoses were tested using next-generation sequencing (NGS). One hundred thirty-two genes associated with spastic paraplegias, hereditary ataxias and related movement disorders were analysed using the Illumina TruSight™ One Sequencing Panel. The targeted NGS data showed pathogenic variants, likely pathogenic variants and those of uncertain significance (VUS) in the following genes: SPAST (spastin, SPG4), ATL1 (atlastin 1, SPG3), WASHC5 (SPG8), KIF5A (SPG10), KIF1A (SPG30), SPG11 (spatacsin), CYP27A1, SETX and ITPR1. Out of the nine genes mentioned above, three have not been directly associated with the HSP phenotype to date. Considering the phenotypic overlap and joint cellular pathways of the HSP, spinocerebellar ataxia (SCA) and amyotrophic lateral sclerosis (ALS) genes, our findings provide further evidence that common genetic testing may improve the diagnostics of movement disorders with a spectrum of ataxia-spasticity signs.
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Affiliation(s)
- Ewelina Elert-Dobkowska
- Department of Genetics, Institute of Psychiatry and Neurology, Sobieskiego 9 Street, 02-957, Warsaw, Poland
| | - Iwona Stepniak
- Department of Genetics, Institute of Psychiatry and Neurology, Sobieskiego 9 Street, 02-957, Warsaw, Poland
| | - Wioletta Krysa
- Department of Genetics, Institute of Psychiatry and Neurology, Sobieskiego 9 Street, 02-957, Warsaw, Poland
| | - Karolina Ziora-Jakutowicz
- Department of Genetics, Institute of Psychiatry and Neurology, Sobieskiego 9 Street, 02-957, Warsaw, Poland
| | - Maria Rakowicz
- Department of Clinical Neurophysiology, Institute of Psychiatry and Neurology, Warsaw, Poland
| | - Anna Sobanska
- Department of Clinical Neurophysiology, Institute of Psychiatry and Neurology, Warsaw, Poland
| | - Jacek Pilch
- Department of Paediatric Neurology, Medical University of Silesia, Katowice, Poland
| | - Dorota Antczak-Marach
- Clinic of Neurology of Children and Adolescents, Institute of Mother and Child, Warsaw, Poland
| | - Jacek Zaremba
- Department of Genetics, Institute of Psychiatry and Neurology, Sobieskiego 9 Street, 02-957, Warsaw, Poland.,Division Five of Medical Sciences, Polish Academy of Science, Warsaw, Poland
| | - Anna Sulek
- Department of Genetics, Institute of Psychiatry and Neurology, Sobieskiego 9 Street, 02-957, Warsaw, Poland.
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38
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Xu F, Takahashi H, Tanaka Y, Ichinose S, Niwa S, Wicklund MP, Hirokawa N. KIF1Bβ mutations detected in hereditary neuropathy impair IGF1R transport and axon growth. J Cell Biol 2018; 217:3480-3496. [PMID: 30126838 PMCID: PMC6168269 DOI: 10.1083/jcb.201801085] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2018] [Revised: 05/31/2018] [Accepted: 07/05/2018] [Indexed: 02/07/2023] Open
Abstract
Uncovering the mechanistic link between kinesin motors and neuropathy, Xu et al. identify functional KIF1Bβ mutations in human hereditary neuropathy to analyze them in mouse models. They propose that KIF1Bβ transports IGF1R and facilitates axonal outgrowth. Both of these effects are significantly affected by the clinical mutations. KIF1Bβ is a kinesin-3 family anterograde motor protein essential for neuronal development, viability, and function. KIF1Bβ mutations have previously been reported in a limited number of pedigrees of Charcot-Marie-Tooth disease type 2A (CMT2A) neuropathy. However, the gene responsible for CMT2A is still controversial, and the mechanism of pathogenesis remains elusive. In this study, we show that the receptor tyrosine kinase IGF1R is a new direct binding partner of KIF1Bβ, and its binding and transport is specifically impaired by the Y1087C mutation of KIF1Bβ, which we detected in hereditary neuropathic patients. The axonal outgrowth and IGF-I signaling of Kif1b−/− neurons were significantly impaired, consistent with decreased surface IGF1R expression. The complementary capacity of KIF1Bβ-Y1087C of these phenotypes was significantly impaired, but the binding capacity to synaptic vesicle precursors was not affected. These data have supported the relevance of KIF1Bβ in IGF1R transport, which may give new clue to the neuropathic pathogenesis.
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Affiliation(s)
- Fang Xu
- Department of Cell Biology and Anatomy, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Hironori Takahashi
- Department of Cell Biology and Anatomy, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Yosuke Tanaka
- Department of Cell Biology and Anatomy, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Sotaro Ichinose
- Department of Cell Biology and Anatomy, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Shinsuke Niwa
- Department of Cell Biology and Anatomy, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | | | - Nobutaka Hirokawa
- Department of Cell Biology and Anatomy, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan .,Center of Excellence in Genome Medicine Research, King Abdulaziz University, Jeddah, Saudi Arabia
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Maciel R, Bis DM, Rebelo AP, Saghira C, Züchner S, Saporta MA. The human motor neuron axonal transcriptome is enriched for transcripts related to mitochondrial function and microtubule-based axonal transport. Exp Neurol 2018; 307:155-163. [PMID: 29935168 DOI: 10.1016/j.expneurol.2018.06.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Revised: 06/05/2018] [Accepted: 06/15/2018] [Indexed: 10/28/2022]
Abstract
Local axonal translation of specific mRNA species plays an important role in axon maintenance, plasticity during development and recovery from injury. Recently, disrupted axonal mRNA transport and translation have been linked to neurodegenerative disorders. To identify mRNA species that are actively transported to axons and play an important role in axonal physiology, we mapped the axonal transcriptome of human induced pluripotent stem cell (iPSC)-derived motor neurons using permeable inserts to obtain large amounts of enriched axonal material for RNA isolation and sequencing. Motor neurons from healthy subjects were used to determine differences in gene expression profiles between neuronal somatodendritic and axonal compartments. Our results demonstrate that several transcripts were enriched in either the axon or neuronal bodies. Gene ontology analysis demonstrated enrichment in the axonal compartment for transcripts associated with mitochondrial electron transport, microtubule-based axonal transport and ER-associated protein catabolism. These results suggest that local translation of mRNAs is required to meet the high-energy demand of axons and to support microtubule-based axonal transport. Interestingly, several transcripts related to human genetic disorders associated with axonal degeneration (inherited axonopathies) were identified among the mRNA species enriched in motor axons.
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Affiliation(s)
- Renata Maciel
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Department of Human Genetics, Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Dana M Bis
- Department of Human Genetics, Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Adriana P Rebelo
- Department of Human Genetics, Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Cima Saghira
- Department of Human Genetics, Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Stephan Züchner
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Department of Human Genetics, Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Mario A Saporta
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Department of Human Genetics, Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL 33136, USA.
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40
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Cutrupi AN, Brewer MH, Nicholson GA, Kennerson M. Structural variations causing inherited peripheral neuropathies: A paradigm for understanding genomic organization, chromatin interactions, and gene dysregulation. Mol Genet Genomic Med 2018; 6:422-433. [PMID: 29573232 PMCID: PMC6014456 DOI: 10.1002/mgg3.390] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 02/09/2018] [Accepted: 03/01/2018] [Indexed: 11/16/2022] Open
Abstract
Inherited peripheral neuropathies (IPNs) are a clinically and genetically heterogeneous group of diseases affecting the motor and sensory peripheral nerves. IPNs have benefited from gene discovery and genetic diagnosis using next-generation sequencing with over 80 causative genes available for testing. Despite this success, up to 50% of cases remain genetically unsolved. In the absence of protein coding mutations, noncoding DNA or structural variation (SV) mutations are a possible explanation. The most common IPN, Charcot-Marie-Tooth neuropathy type 1A (CMT1A), is caused by a 1.5 Mb duplication causing trisomy of the dosage sensitive gene PMP22. Using genome sequencing, we recently identified two large genomic rearrangements causing IPN subtypes X-linked CMT (CMTX3) and distal hereditary motor neuropathy (DHMN1), thereby expanding the spectrum of SV mutations causing IPN. Understanding how newly discovered SVs can cause IPN may serve as a useful paradigm to examine the role of topologically associated domains (TADs), chromatin interactions, and gene dysregulation in disease. This review will describe the growing role of SV in the pathogenesis of IPN and the importance of considering this type of mutation in Mendelian diseases where protein coding mutations cannot be identified.
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Affiliation(s)
- Anthony N. Cutrupi
- Northcott Neuroscience LaboratoryANZAC Research InstituteSydneyNSWAustralia
- Sydney Medical SchoolUniversity of SydneySydneyNSWAustralia
| | - Megan H. Brewer
- Northcott Neuroscience LaboratoryANZAC Research InstituteSydneyNSWAustralia
- Sydney Medical SchoolUniversity of SydneySydneyNSWAustralia
| | - Garth A. Nicholson
- Northcott Neuroscience LaboratoryANZAC Research InstituteSydneyNSWAustralia
- Sydney Medical SchoolUniversity of SydneySydneyNSWAustralia
- Molecular Medicine LaboratoryConcord HospitalSydneyNSWAustralia
| | - Marina L. Kennerson
- Northcott Neuroscience LaboratoryANZAC Research InstituteSydneyNSWAustralia
- Sydney Medical SchoolUniversity of SydneySydneyNSWAustralia
- Molecular Medicine LaboratoryConcord HospitalSydneyNSWAustralia
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Hartley T, Wagner JD, Warman-Chardon J, Tétreault M, Brady L, Baker S, Tarnopolsky M, Bourque PR, Parboosingh JS, Smith C, McInnes B, Innes AM, Bernier F, Curry CJ, Yoon G, Horvath GA, Bareke E, Gillespie M, Majewski J, Bulman DE, Dyment DA, Boycott KM. Whole-exome sequencing is a valuable diagnostic tool for inherited peripheral neuropathies: Outcomes from a cohort of 50 families. Clin Genet 2017; 93:301-309. [PMID: 28708278 DOI: 10.1111/cge.13101] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Revised: 07/04/2017] [Accepted: 07/09/2017] [Indexed: 01/02/2023]
Abstract
The inherited peripheral neuropathies (IPNs) are characterized by marked clinical and genetic heterogeneity and include relatively frequent presentations such as Charcot-Marie-Tooth disease and hereditary motor neuropathy, as well as more rare conditions where peripheral neuropathy is associated with additional features. There are over 250 genes known to cause IPN-related disorders but it is estimated that in approximately 50% of affected individuals a molecular diagnosis is not achieved. In this study, we examine the diagnostic utility of whole-exome sequencing (WES) in a cohort of 50 families with 1 or more affected individuals with a molecularly undiagnosed IPN with or without additional features. Pathogenic or likely pathogenic variants in genes known to cause IPN were identified in 24% (12/50) of the families. A further 22% (11/50) of families carried sequence variants in IPN genes in which the significance remains unclear. An additional 12% (6/50) of families had variants in novel IPN candidate genes, 3 of which have been published thus far as novel discoveries (KIF1A, TBCK, and MCM3AP). This study highlights the use of WES in the molecular diagnostic approach of highly heterogeneous disorders, such as IPNs, places it in context of other published neuropathy cohorts, while further highlighting associated benefits for discovery.
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Affiliation(s)
- T Hartley
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Canada
| | - J D Wagner
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Canada
| | - J Warman-Chardon
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Canada.,Department of Genetics, Children's Hospital of Eastern Ontario, Ottawa, Canada
| | - M Tétreault
- Department of Human Genetics, McGill University, Montréal, Canada
| | - L Brady
- Department of Pediatrics, McMaster University Medical Centre, Hamilton, Canada
| | - S Baker
- Department of Medicine, McMaster University Medical Centre, Hamilton, Canada
| | - M Tarnopolsky
- Department of Pediatrics, McMaster University Medical Centre, Hamilton, Canada
| | - P R Bourque
- Department of Medicine, University of Ottawa, Ottawa, Canada
| | - J S Parboosingh
- Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - C Smith
- Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - B McInnes
- Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - A M Innes
- Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, Canada.,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Canada
| | - F Bernier
- Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, Canada.,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Canada
| | - C J Curry
- Department of Pediatrics, University of California, San Francisco, California
| | - G Yoon
- Divisions of Neurology and Clinical and Metabolic Genetics, The Hospital for Sick Children, University of Toronto, Toronto, Canada
| | - G A Horvath
- Division of Biochemical Diseases, Department of Pediatrics, B.C. Children's Hospital, University of British Columbia, Vancouver, Canada
| | - E Bareke
- Department of Human Genetics, McGill University, Montréal, Canada
| | - M Gillespie
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Canada
| | | | | | - J Majewski
- Department of Human Genetics, McGill University, Montréal, Canada
| | - D E Bulman
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Canada
| | - D A Dyment
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Canada.,Department of Genetics, Children's Hospital of Eastern Ontario, Ottawa, Canada
| | - K M Boycott
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Canada.,Department of Genetics, Children's Hospital of Eastern Ontario, Ottawa, Canada
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42
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Pang SYY, Teo KC, Hsu JS, Chang RSK, Li M, Sham PC, Ho SL. The role of gene variants in the pathogenesis of neurodegenerative disorders as revealed by next generation sequencing studies: a review. Transl Neurodegener 2017; 6:27. [PMID: 29046784 PMCID: PMC5639582 DOI: 10.1186/s40035-017-0098-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 10/02/2017] [Indexed: 12/13/2022] Open
Abstract
The clinical diagnosis of neurodegenerative disorders based on phenotype is difficult in heterogeneous conditions with overlapping symptoms. It does not take into account the disease etiology or the highly variable clinical course even amongst patients diagnosed with the same disorder. The advent of next generation sequencing (NGS) has allowed for a system-wide, unbiased approach to identify all gene variants in the genome simultaneously. With the plethora of new genes being identified, genetic rather than phenotype-based classification of Mendelian diseases such as spinocerebellar ataxia (SCA), hereditary spastic paraplegia (HSP) and Charcot-Marie-Tooth disease (CMT) has become widely accepted. It has also become clear that gene variants play a role in common and predominantly sporadic neurodegenerative diseases such as Parkinson’s disease (PD) and amyotrophic lateral sclerosis (ALS). The observation of pleiotropy has emerged, with mutations in the same gene giving rise to diverse phenotypes, which further increases the complexity of phenotype-genotype correlation. Possible mechanisms of pleiotropy include different downstream effects of different mutations in the same gene, presence of modifier genes, and oligogenic inheritance. Future directions include development of bioinformatics tools and establishment of more extensive public genotype/phenotype databases to better distinguish deleterious gene variants from benign polymorphisms, translation of genetic findings into pathogenic mechanisms through in-vitro and in-vivo studies, and ultimately finding disease-modifying therapies for neurodegenerative disorders.
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Affiliation(s)
- Shirley Yin-Yu Pang
- Division of Neurology, Department of Medicine, Queen Mary Hospital, University of Hong Kong, Hong Kong, People's Republic of China
| | - Kay-Cheong Teo
- Division of Neurology, Department of Medicine, Queen Mary Hospital, University of Hong Kong, Hong Kong, People's Republic of China
| | - Jacob Shujui Hsu
- Centre for Genomic Sciences, University of Hong Kong, Hong Kong, People's Republic of China
| | - Richard Shek-Kwan Chang
- Division of Neurology, Department of Medicine, Queen Mary Hospital, University of Hong Kong, Hong Kong, People's Republic of China
| | - Miaoxin Li
- Centre for Genomic Sciences, University of Hong Kong, Hong Kong, People's Republic of China.,Department of Medical Genetics, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, People's Republic of China.,Key Laboratory of Tropical Disease Control (SYSU), Ministry of Education, Guangzhou, People's Republic of China
| | - Pak-Chung Sham
- Centre for Genomic Sciences, University of Hong Kong, Hong Kong, People's Republic of China
| | - Shu-Leong Ho
- Division of Neurology, Department of Medicine, Queen Mary Hospital, University of Hong Kong, Hong Kong, People's Republic of China
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43
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Horga A, Laurà M, Jaunmuktane Z, Jerath NU, Gonzalez MA, Polke JM, Poh R, Blake JC, Liu YT, Wiethoff S, Bettencourt C, Lunn MP, Manji H, Hanna MG, Houlden H, Brandner S, Züchner S, Shy M, Reilly MM. Genetic and clinical characteristics of NEFL-related Charcot-Marie-Tooth disease. J Neurol Neurosurg Psychiatry 2017; 88:575-585. [PMID: 28501821 PMCID: PMC5580821 DOI: 10.1136/jnnp-2016-315077] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 01/20/2017] [Accepted: 01/24/2017] [Indexed: 11/03/2022]
Abstract
OBJECTIVES To analyse and describe the clinical and genetic spectrum of Charcot-Marie-Tooth disease (CMT) caused by mutations in the neurofilament light polypeptide gene (NEFL). METHODS Combined analysis of newly identified patients with NEFL-related CMT and all previously reported cases from the literature. RESULTS Five new unrelated patients with CMT carrying the NEFL mutations P8R and N98S and the novel variant L311P were identified. Combined data from these cases and 62 kindreds from the literature revealed four common mutations (P8R, P22S, N98S and E396K) and three mutational hotspots accounting for 37 (55%) and 50 (75%) kindreds, respectively. Eight patients had de novo mutations. Loss of large-myelinated fibres was a uniform feature in a total of 21 sural nerve biopsies and 'onion bulb' formations and/or thin myelin sheaths were observed in 14 (67%) of them. The neurophysiological phenotype was broad but most patients with E90K and N98S had upper limb motor conduction velocities <38 m/s. Age of onset was ≤3 years in 25 cases. Pyramidal tract signs were described in 13 patients and 7 patients were initially diagnosed with or tested for inherited ataxia. Patients with E90K and N98S frequently presented before age 3 years and developed hearing loss or other neurological features including ataxia and/or cerebellar atrophy on brain MRI. CONCLUSIONS NEFL-related CMT is clinically and genetically heterogeneous. Based on this study, however, we propose mutational hotspots and relevant clinical-genetic associations that may be helpful in the evaluation of NEFL sequence variants and the differential diagnosis with other forms of CMT.
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Affiliation(s)
- Alejandro Horga
- MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology, London, UK.,Department of Neurology, Hospital Clinico Universitario San Carlos, Madrid, Spain
| | - Matilde Laurà
- MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology, London, UK.,UCL Institute of Neurology, MRC Centre for Neuromuscular Diseases, National Hospital for Neurology and Neurosurgery, London, UK
| | - Zane Jaunmuktane
- Division of Neuropathology and Department of Neurodegenerative Disease, The National Hospital for Neurology and Neurosurgery and UCL Institute of Neurology, London, UK
| | | | - Michael A Gonzalez
- Department of Human Genetics and Hussman Institute for Human Genomics, Miller School of Medicine, University of Miami, Miami, Florida, USA.,The Genesis Project Foundation, The Genesis Project Foundation, Miami, Florida, USA
| | - James M Polke
- Department of Neurogenetics, The National Hospital for Neurology and Neurosurgery and UCL Institute of Neurology, London, UK.,Neurogenetics Unit, National Hospital for Neurology and Neurosurgery, London, UK
| | - Roy Poh
- Department of Neurogenetics, The National Hospital for Neurology and Neurosurgery and UCL Institute of Neurology, London, UK
| | - Julian C Blake
- Department of Clinical Neurophysiology, National Hospital for Neurology and Neurosurgery (and Norfolk and Norwich University Hospital), London, UK
| | - Yo-Tsen Liu
- MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology, London, UK.,Department of Neurology, Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Sarah Wiethoff
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
| | | | - Michael Pt Lunn
- Department of Neurology, National Hospital for Neurology and Neurosurgery, London, UK
| | - Hadi Manji
- MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology, London, UK
| | - Michael G Hanna
- MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology, London, UK
| | - Henry Houlden
- MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology and National Hospital for Neurology and Neurosurgery, London, UK
| | - Sebastian Brandner
- Division of Neuropatholgoy, UCL Institute of Neurology and National Hospital for Neurology and Neurosurgery, London, UK
| | | | - Michael Shy
- Department of Neurology, University of Iowa, Iowa City, Iowa, USA.,Wayne State University, Michigan, Michigan, USA
| | - Mary M Reilly
- MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology, London, UK.,MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology and National Hospital for Neurology and Neurosurgery, London, UK
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44
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Walsh M, Bell KM, Chong B, Creed E, Brett GR, Pope K, Thorne NP, Sadedin S, Georgeson P, Phelan DG, Day T, Taylor JA, Sexton A, Lockhart PJ, Kiers L, Fahey M, Macciocca I, Gaff CL, Oshlack A, Yiu EM, James PA, Stark Z, Ryan MM. Diagnostic and cost utility of whole exome sequencing in peripheral neuropathy. Ann Clin Transl Neurol 2017; 4:318-325. [PMID: 28491899 PMCID: PMC5420808 DOI: 10.1002/acn3.409] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 03/07/2017] [Accepted: 03/15/2017] [Indexed: 12/15/2022] Open
Abstract
Objective To explore the diagnostic utility and cost effectiveness of whole exome sequencing (WES) in a cohort of individuals with peripheral neuropathy. Methods Singleton WES was performed in individuals recruited though one pediatric and one adult tertiary center between February 2014 and December 2015. Initial analysis was restricted to a virtual panel of 55 genes associated with peripheral neuropathies. Patients with uninformative results underwent expanded analysis of the WES data. Data on the cost of prior investigations and assessments performed for diagnostic purposes in each patient was collected. Results Fifty patients with a peripheral neuropathy were recruited (median age 18 years; range 2–68 years). The median time from initial presentation to study enrollment was 6 years 9 months (range 2 months–62 years), and the average cost of prior investigations and assessments for diagnostic purposes AU$4013 per patient. Eleven individuals received a diagnosis from the virtual panel. Eight individuals received a diagnosis following expanded analysis of the WES data, increasing the overall diagnostic yield to 38%. Two additional individuals were diagnosed with pathogenic copy number variants through SNP microarray. Conclusions This study provides evidence that WES has a high diagnostic utility and is cost effective in patients with a peripheral neuropathy. Expanded analysis of WES data significantly improves the diagnostic yield in patients in whom a diagnosis is not found on the initial targeted analysis. This is primarily due to diagnosis of conditions caused by newly discovered genes and the resolution of complex and atypical phenotypes.
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Affiliation(s)
- Maie Walsh
- Murdoch Childrens Research Institute Melbourne Australia.,Royal Melbourne Hospital Melbourne Australia
| | - Katrina M Bell
- Murdoch Childrens Research Institute Melbourne Australia
| | - Belinda Chong
- Murdoch Childrens Research Institute Melbourne Australia
| | - Emma Creed
- Royal Melbourne Hospital Melbourne Australia.,Melbourne Genomics Health Alliance Melbourne Australia
| | - Gemma R Brett
- Murdoch Childrens Research Institute Melbourne Australia.,Melbourne Genomics Health Alliance Melbourne Australia
| | - Kate Pope
- Murdoch Childrens Research Institute Melbourne Australia
| | - Natalie P Thorne
- Melbourne Genomics Health Alliance Melbourne Australia.,Murdoch Childrens Research Institute Melbourne Australia.,University of Melbourne Melbourne Australia
| | - Simon Sadedin
- Murdoch Childrens Research Institute Melbourne Australia
| | | | - Dean G Phelan
- Murdoch Childrens Research Institute Melbourne Australia
| | - Timothy Day
- Royal Melbourne Hospital Melbourne Australia
| | | | | | - Paul J Lockhart
- Murdoch Childrens Research Institute Melbourne Australia.,Bruce Lefroy Centre Murdoch Childrens Research Institute Parkville Australia.,Department of Paediatrics The University of Melbourne Melbourne Australia
| | | | | | - Ivan Macciocca
- Murdoch Childrens Research Institute Melbourne Australia.,Melbourne Genomics Health Alliance Melbourne Australia
| | - Clara L Gaff
- Melbourne Genomics Health Alliance Melbourne Australia.,University of Melbourne Melbourne Australia
| | - Alicia Oshlack
- Murdoch Childrens Research Institute Melbourne Australia.,University of Melbourne Melbourne Australia
| | - Eppie M Yiu
- Bruce Lefroy Centre Murdoch Childrens Research Institute Parkville Australia.,Department of Paediatrics The University of Melbourne Melbourne Australia.,Royal Children's Hospital Melbourne Australia
| | - Paul A James
- Royal Melbourne Hospital Melbourne Australia.,University of Melbourne Melbourne Australia
| | - Zornitza Stark
- Murdoch Childrens Research Institute Melbourne Australia
| | - Monique M Ryan
- Murdoch Childrens Research Institute Melbourne Australia.,Melbourne Genomics Health Alliance Melbourne Australia.,Department of Paediatrics The University of Melbourne Melbourne Australia.,Royal Children's Hospital Melbourne Australia
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45
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Lee JJY, van Karnebeek CDM, Drögemoller B, Shyr C, Tarailo-Graovac M, Eydoux P, Ross CJ, Wasserman WW, Björnson B, Wu JK. Further Validation of the SIGMAR1 c.151+1G>T Mutation as Cause of Distal Hereditary Motor Neuropathy. Child Neurol Open 2016; 3:2329048X16669912. [PMID: 28503617 PMCID: PMC5417346 DOI: 10.1177/2329048x16669912] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 07/16/2016] [Accepted: 08/11/2016] [Indexed: 12/17/2022] Open
Abstract
Distal hereditary motor neuropathies represent a group of rare genetic disorders characterized by progressive distal motor weakness without sensory loss. Their genetic heterogeneity is high and thus eligible for diagnostic whole exome sequencing. The authors report successful application of whole exome sequencing in diagnosing a second consanguineous family with distal hereditary motor neuropathy due to a homozygous c.151+1G>T variant in SIGMAR1. This variant was recently proposed as causal for the same condition in a consanguineous Chinese family. Compared to this family, the Afghan ethnic origin of our patient is distinct, yet the features are identical, validating the SIGMAR1 deficiency phenotype: progressive muscle wasting/weakness in lower and upper limbs without sensory loss. Rapid disease progression during adolescent growth is similar and may be due to SIGMAR1’s role in regulating axon elongation and tau phosphorylation. Finally, the authors conclude that SIGMAR1 deficiency should be added to the differential diagnosis of distal hereditary motor neuropathies.
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Affiliation(s)
- Jessica J Y Lee
- Centre for Molecular Medicine and Therapeutics, Vancouver, British Columbia, Canada.,Treatable Intellectual Disability Endeavour in British Columbia, Vancouver, British Columbia, Canada.,BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada
| | - Clara D M van Karnebeek
- Centre for Molecular Medicine and Therapeutics, Vancouver, British Columbia, Canada.,Treatable Intellectual Disability Endeavour in British Columbia, Vancouver, British Columbia, Canada.,BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada.,Division of Biochemical Diseases, Department of Pediatrics, BC Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Britt Drögemoller
- BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada.,Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Casper Shyr
- Centre for Molecular Medicine and Therapeutics, Vancouver, British Columbia, Canada.,Treatable Intellectual Disability Endeavour in British Columbia, Vancouver, British Columbia, Canada.,BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada
| | - Maja Tarailo-Graovac
- Centre for Molecular Medicine and Therapeutics, Vancouver, British Columbia, Canada.,Treatable Intellectual Disability Endeavour in British Columbia, Vancouver, British Columbia, Canada.,BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada.,Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Patrice Eydoux
- Treatable Intellectual Disability Endeavour in British Columbia, Vancouver, British Columbia, Canada.,BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada.,Cytogenetics Laboratory, Department of Pathology and Laboratory Medicine, BC Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Colin J Ross
- Centre for Molecular Medicine and Therapeutics, Vancouver, British Columbia, Canada.,Treatable Intellectual Disability Endeavour in British Columbia, Vancouver, British Columbia, Canada.,BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada.,Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Wyeth W Wasserman
- Centre for Molecular Medicine and Therapeutics, Vancouver, British Columbia, Canada.,Treatable Intellectual Disability Endeavour in British Columbia, Vancouver, British Columbia, Canada.,BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada.,Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Bruce Björnson
- BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada.,Division of Pediatric Neurology, Department of Pediatrics, BC Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - John K Wu
- BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada.,Division of Hematology/Oncology/BMT, Department of Pediatrics, BC Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
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46
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Alaei MR, Talebi S, Ghofrani M, Taghizadeh M, Keramatipour M. Whole Exome Sequencing Reveals a BSCL2 Mutation Causing Progressive Encephalopathy with Lipodystrophy (PELD) in an Iranian Pediatric Patient. IRANIAN BIOMEDICAL JOURNAL 2016; 20:295-301. [PMID: 27452399 PMCID: PMC5075143 DOI: 10.22045/ibj.2016.07] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Background: Progressive encephalopathy with or without lipodystrophy is a rare autosomal recessive childhood-onset seipin-associated neurodegenerative syndrome, leading to developmental regression of motor and cognitive skills. In this study, we introduce a patient with developmental regression and autism. The causative mutation was found by exome sequencing. Methods: The proband showed a generalized hypertonia and regression of all developmental milestones. Based on the advantages of next-generation sequencing (NGS), whole exome sequencing (WES) was requested. The functional significance of variants was evaluated by NGS-specific prediction servers. Sanger sequencing was used for segregation analysis in the family. Results: There was no specific sign in the clinical and paraclinical investigations of the patient to establish a conclusive clinical diagnosis. WES detected a known homozygous nonsense mutation in BSCL2 (NM_001122955.3:c. 985C>T; p.Arg329*). The variant is segregating in the pedigree with an autosomal recessive pattern. Conclusion: Exome sequencing is a robust method for identifying the candidate gene variants in Mendelian traits.
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Affiliation(s)
- Mohammad Reza Alaei
- Department of Pediatric Endocrinology, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Saeed Talebi
- Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Ghofrani
- Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohsen Taghizadeh
- Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Keramatipour
- Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
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47
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Brewer MH, Chaudhry R, Qi J, Kidambi A, Drew AP, Menezes MP, Ryan MM, Farrar MA, Mowat D, Subramanian GM, Young HK, Zuchner S, Reddel SW, Nicholson GA, Kennerson ML. Whole Genome Sequencing Identifies a 78 kb Insertion from Chromosome 8 as the Cause of Charcot-Marie-Tooth Neuropathy CMTX3. PLoS Genet 2016; 12:e1006177. [PMID: 27438001 PMCID: PMC4954712 DOI: 10.1371/journal.pgen.1006177] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 06/15/2016] [Indexed: 11/18/2022] Open
Abstract
With the advent of whole exome sequencing, cases where no pathogenic coding mutations can be found are increasingly being observed in many diseases. In two large, distantly-related families that mapped to the Charcot-Marie-Tooth neuropathy CMTX3 locus at chromosome Xq26.3-q27.3, all coding mutations were excluded. Using whole genome sequencing we found a large DNA interchromosomal insertion within the CMTX3 locus. The 78 kb insertion originates from chromosome 8q24.3, segregates fully with the disease in the two families, and is absent from the general population as well as 627 neurologically normal chromosomes from in-house controls. Large insertions into chromosome Xq27.1 are known to cause a range of diseases and this is the first neuropathy phenotype caused by an interchromosomal insertion at this locus. The CMTX3 insertion represents an understudied pathogenic structural variation mechanism for inherited peripheral neuropathies. Our finding highlights the importance of considering all structural variation types when studying unsolved inherited peripheral neuropathy cases with no pathogenic coding mutations.
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Affiliation(s)
- Megan H. Brewer
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Concord, New South Wales, Australia
- Sydney Medical School, University of Sydney, Camperdown, New South Wales, Australia
- * E-mail:
| | - Rabia Chaudhry
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Concord, New South Wales, Australia
- Sydney Medical School, University of Sydney, Camperdown, New South Wales, Australia
| | - Jessica Qi
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Concord, New South Wales, Australia
- Discipline of Pathology, University of Sydney, Camperdown, New South Wales, Australia
| | - Aditi Kidambi
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Concord, New South Wales, Australia
| | - Alexander P. Drew
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Concord, New South Wales, Australia
| | - Manoj P. Menezes
- The Institute for Neuroscience and Muscle Research, The Children’s Hospital at Westmead, Westmead, New South Wales, Australia
- T.Y. Nelson Department of Neurology and Neurosurgery, The Children’s Hospital at Westmead, Westmead, New South Wales, Australia
- Paediatrics and Child Health, University of Sydney, Camperdown, New South Wales, Australia
| | - Monique M. Ryan
- Department of Neurology, Royal Children’s Hospital, Parkville, Victoria, Australia
- Murdoch Childrens Research Institute, Parkville, Victoria, Australia
- Department of Paediatrics, University of Melbourne, Parkville, Victoria, Australia
| | - Michelle A. Farrar
- Department of Neurology, Sydney Children’s Hospital, Randwick, New South Wales, Australia
- School of Women’s and Children’s Health, UNSW Medicine, University of New South Wales, Kensington, New South Wales, Australia
| | - David Mowat
- School of Women’s and Children’s Health, UNSW Medicine, University of New South Wales, Kensington, New South Wales, Australia
- Department of Medical Genetics, Sydney Children’s Hospital, Randwick, New South Wales, Australia
| | - Gopinath M. Subramanian
- Department of Paediatrics, John Hunter Children’s Hospital, Newcastle, New South Wales, Australia
| | - Helen K. Young
- Department of Paediatrics, Royal North Shore Hospital, St Leonards, New South Wales, Australia
- Northern Clinical School, Sydney Medical School, University of Sydney, St Leonards, New South Wales, Australia
- Department of Neurogenetics, The Children’s Hospital at Westmead, Westmead, New South Wales, Australia
| | - Stephan Zuchner
- John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, Florida, United States of America
- Dr. John T. Macdonald Department of Human Genetics, University of Miami Miller School of Medicine, Miami, Florida, United States of America
| | - Stephen W. Reddel
- Department of Neurology, Concord Repatriation General Hospital, Concord, New South Wales, Australia
| | - Garth A. Nicholson
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Concord, New South Wales, Australia
- Sydney Medical School, University of Sydney, Camperdown, New South Wales, Australia
- Molecular Medicine, Concord Repatriation General Hospital, Concord, New South Wales, Australia
| | - Marina L. Kennerson
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Concord, New South Wales, Australia
- Sydney Medical School, University of Sydney, Camperdown, New South Wales, Australia
- Molecular Medicine, Concord Repatriation General Hospital, Concord, New South Wales, Australia
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48
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Nam SH, Hong YB, Hyun YS, Nam DE, Kwak G, Hwang SH, Choi BO, Chung KW. Identification of Genetic Causes of Inherited Peripheral Neuropathies by Targeted Gene Panel Sequencing. Mol Cells 2016; 39:382-8. [PMID: 27025386 PMCID: PMC4870185 DOI: 10.14348/molcells.2016.2288] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Revised: 02/11/2016] [Accepted: 02/22/2016] [Indexed: 12/19/2022] Open
Abstract
Inherited peripheral neuropathies (IPN), which are a group of clinically and genetically heterogeneous peripheral nerve disorders including Charcot-Marie-Tooth disease (CMT), exhibit progressive degeneration of muscles in the extremities and loss of sensory function. Over 70 genes have been reported as genetic causatives and the number is still growing. We prepared a targeted gene panel for IPN diagnosis based on next generation sequencing (NGS). The gene panel was designed to detect mutations in 73 genes reported to be genetic causes of IPN or related peripheral neuropathies, and to detect duplication of the chromosome 17p12 region, the major genetic cause of CMT1A. We applied the gene panel to 115 samples from 63 non-CMT1A families, and isolated 15 pathogenic or likely-pathogenic mutations in eight genes from 25 patients (17 families). Of them, eight mutations were unreported variants. Of particular interest, this study revealed several very rare mutations in the SPTLC2, DCTN1, and MARS genes. In addition, the effectiveness of the detection of CMT1A was confirmed by comparing five 17p12-nonduplicated controls and 15 CMT1A cases. In conclusion, we developed a gene panel for one step genetic diagnosis of IPN. It seems that its time- and cost-effectiveness are superior to previous tiered-genetic diagnosis algorithms, and it could be applied as a genetic diagnostic system for inherited peripheral neuropathies.
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Affiliation(s)
- Soo Hyun Nam
- Department of Biological Sciences, Kongju National University, Gongju 32588,
Korea
| | - Young Bin Hong
- Stem Cell & Regenerative Medicine Center and Neuroscience Center, Samsung Medical Center, Seoul 06351,
Korea
| | - Young Se Hyun
- Department of Biological Sciences, Kongju National University, Gongju 32588,
Korea
| | - Da Eun Nam
- Department of Biological Sciences, Kongju National University, Gongju 32588,
Korea
| | - Geon Kwak
- Department of Neurology, Sungkyunkwan University School of Medicine, Seoul 06351,
Korea
- Department of Health Sciences and Technology, Samsung Advanced Institute for Health Science & Tech., Sungkyunkwan University, Seoul 06351,
Korea
| | - Sun Hee Hwang
- Department of Neurology, Sungkyunkwan University School of Medicine, Seoul 06351,
Korea
| | - Byung-Ok Choi
- Stem Cell & Regenerative Medicine Center and Neuroscience Center, Samsung Medical Center, Seoul 06351,
Korea
- Department of Neurology, Sungkyunkwan University School of Medicine, Seoul 06351,
Korea
- Department of Health Sciences and Technology, Samsung Advanced Institute for Health Science & Tech., Sungkyunkwan University, Seoul 06351,
Korea
| | - Ki Wha Chung
- Department of Biological Sciences, Kongju National University, Gongju 32588,
Korea
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49
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Chen H, Zhou X, Wang J, Wang X, Liu L, Wu S, Li T, Chen S, Yang J, Sham PC, Zhu G, Zhang X, Wang B. Exome Sequencing and Gene Prioritization Correct Misdiagnosis in a Chinese Kindred with Familial Amyloid Polyneuropathy. Sci Rep 2016; 6:26362. [PMID: 27212199 PMCID: PMC4876459 DOI: 10.1038/srep26362] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 04/26/2016] [Indexed: 11/09/2022] Open
Abstract
Inherited neuropathies show considerable heterogeneity in clinical manifestations and genetic etiologies, and are therefore often difficult to diagnose. Whole-exome sequencing (WES) has been widely adopted to make definite diagnosis of unclear conditions, with proven efficacy in optimizing patients' management. In this study, a large Chinese kindred segregating autosomal dominant polyneuropathy with incomplete penetrance was ascertained through a patient who was initially diagnosed as Charcot-Marie-Tooth disease. To investigate the genetic cause, forty-six living family members were genotyped by SNP microarrays, and one confirmed patient was subject to WES. Through systematic computational prioritization, we identified a missense mutation c.G148T in TTR gene which results in a p.V50L substitution known to cause transthyretin-related familial amyloid polyneuropathy. Co-segregation analysis and clinical follow-up confirmed the new diagnosis, which suggested new therapeutic options to the patients and informed high risk family members. This study confirms WES as a powerful tool in translational medicine, and further demostrates the practical utility of gene prioritization in narrowing the scope of causative mutation.
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Affiliation(s)
- Hui Chen
- Department of Neurology, Military General Hospital of Beijing PLA, Beijing, China
| | - Xueya Zhou
- MOE Key Laboratory of Bioinformatics, Bioinformatics Division and Center for Synthetic and Systems Biology, TNLIST/Department of Automation, Tsinghua University, Beijing, China.,Department of Psychiatry and Centre for Genomic Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Jing Wang
- Department of Medical Genetics, The Capital Medical University, Beijing, China
| | - Xi Wang
- National Research Institute of Family Planning, Beijing, China
| | - Liyang Liu
- MOE Key Laboratory of Bioinformatics, Bioinformatics Division and Center for Synthetic and Systems Biology, TNLIST/Department of Automation, Tsinghua University, Beijing, China
| | - Shinan Wu
- National Research Institute of Family Planning, Beijing, China
| | - Tengyan Li
- National Research Institute of Family Planning, Beijing, China
| | - Si Chen
- National Research Institute of Family Planning, Beijing, China
| | - Jingwen Yang
- National Research Institute of Family Planning, Beijing, China
| | - Pak Chung Sham
- Department of Psychiatry and Centre for Genomic Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Guangming Zhu
- Department of Neurology, Military General Hospital of Beijing PLA, Beijing, China
| | - Xuegong Zhang
- MOE Key Laboratory of Bioinformatics, Bioinformatics Division and Center for Synthetic and Systems Biology, TNLIST/Department of Automation, Tsinghua University, Beijing, China
| | - Binbin Wang
- National Research Institute of Family Planning, Beijing, China
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50
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EGR2 mutation enhances phenotype spectrum of Dejerine–Sottas syndrome. J Neurol 2016; 263:1456-8. [DOI: 10.1007/s00415-016-8153-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 04/27/2016] [Accepted: 04/28/2016] [Indexed: 10/21/2022]
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