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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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Dorn GW. Reversing Dysdynamism to Interrupt Mitochondrial Degeneration in Amyotrophic Lateral Sclerosis. Cells 2023; 12:1188. [PMID: 37190097 PMCID: PMC10136928 DOI: 10.3390/cells12081188] [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: 03/01/2023] [Revised: 04/13/2023] [Accepted: 04/14/2023] [Indexed: 05/17/2023] Open
Abstract
Amyotrophic lateral sclerosis is one of several chronic neurodegenerative conditions in which mitochondrial abnormalities are posited to contribute to disease progression. Therapeutic options targeting mitochondria include enhancing metabolism, suppressing reactive oxygen production and disrupting mitochondria-mediated programmed cell death pathways. Herein is reviewed mechanistic evidence supporting a meaningful pathophysiological role for the constellation of abnormal mitochondrial fusion, fission and transport, collectively designated mitochondrial dysdynamism, in ALS. Following this is a discussion on preclinical studies in ALS mice that seemingly validate the idea that normalizing mitochondrial dynamism can delay ALS by interrupting a vicious cycle of mitochondrial degeneration, leading to neuronal die-back and death. Finally, the relative benefits of suppressing mitochondrial fusion vs. enhancing mitochondrial fusion in ALS are speculated upon, and the paper concludes with the prediction that the two approaches could be additive or synergistic, although a side-by-side comparative trial may be challenging to perform.
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Affiliation(s)
- Gerald W Dorn
- Department of Internal Medicine (Pharmacogenomics), Washington University School of Medicine, St. Louis, MO 63110, USA
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3
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Evaluation of optical coherence tomography findings and visual evoked potentials in Charcot-Marie-Tooth disease. Int Ophthalmol 2023; 43:333-341. [PMID: 35953577 DOI: 10.1007/s10792-022-02452-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 07/31/2022] [Indexed: 02/07/2023]
Abstract
PURPOSE To evaluate the spectral-domain optical coherence tomography (SD-OCT) findings and pattern visual evoked potential (VEP) in Charcot-Marie-Tooth (CMT) disease. METHODS Seventeen patients with CMT disease and 17 control subjects were included in the study. The patients were divided into two groups according to conduction velocity and inheritance pattern as demyelinating type (CMT 1) and axonal type (CMT 2). The average retinal nerve fiber layer (RNFL) thickness, RNFL thicknesses of all quadrants, and thicknesses of the ganglion cell layer complex (GCC) were measured using SD-OCT. Pattern VEP recordings were evaluated in both groups. RESULTS The average and four quadrants of RNFL thicknesses, and superior and inferior GCC thicknesses were significantly thinner in the CMT patients compared with healthy individuals, but there were no statistically significant differences between the CMT groups. There was a significant positive correlation between age and all RNFL and GCC thicknesses in the CMT 2 group and between age and RNFL thickness of the temporal quadrant in the CMT 1 group. P100 latencies were significantly delayed in the CMT groups compared with controls, and there were no significant differences in P100 latencies between the CMT groups (p < 0.001). VEP amplitudes were in normal ranges in the CMT groups. CONCLUSION This study showed that RNFL and GCC thicknesses were significantly reduced and VEP latencies were prolonged in patients with CMT with normal clinical examinations. Our results suggest that optic nerves may be affected more frequently in patients with CMT that is detected in clinical examinations.
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Zaman M, Shutt TE. The Role of Impaired Mitochondrial Dynamics in MFN2-Mediated Pathology. Front Cell Dev Biol 2022; 10:858286. [PMID: 35399520 PMCID: PMC8989266 DOI: 10.3389/fcell.2022.858286] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 03/07/2022] [Indexed: 12/17/2022] Open
Abstract
The Mitofusin 2 protein (MFN2), encoded by the MFN2 gene, was first described for its role in mediating mitochondrial fusion. However, MFN2 is now recognized to play additional roles in mitochondrial autophagy (mitophagy), mitochondrial motility, lipid transfer, and as a tether to other organelles including the endoplasmic reticulum (ER) and lipid droplets. The tethering role of MFN2 is an important mediator of mitochondrial-ER contact sites (MERCs), which themselves have many important functions that regulate mitochondria, including calcium homeostasis and lipid metabolism. Exemplifying the importance of MFN2, pathogenic variants in MFN2 are established to cause the peripheral neuropathy Charcot-Marie-Tooth Disease Subtype 2A (CMT2A). However, the mechanistic basis for disease is not clear. Moreover, additional pathogenic phenotypes such as lipomatosis, distal myopathy, optic atrophy, and hearing loss, can also sometimes be present in patients with CMT2A. Given these variable patient phenotypes, and the many cellular roles played by MFN2, the mechanistic underpinnings of the cellular impairments by which MFN2 dysfunction leads to disease are likely to be complex. Here, we will review what is known about the various functions of MFN2 that are impaired by pathogenic variants causing CMT2A, with a specific emphasis on the ties between MFN2 variants and MERCs.
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Affiliation(s)
- Mashiat Zaman
- Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, AB, Canada
- Alberta Children’s Hospital Research Institute (ACHRI), Calgary, AB, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Timothy E. Shutt
- Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, AB, Canada
- Alberta Children’s Hospital Research Institute (ACHRI), Calgary, AB, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
- Department of Medical Genetics, University of Calgary, Calgary, AB, Canada
- *Correspondence: Timothy E. Shutt,
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Lenaers G, Neutzner A, Le Dantec Y, Jüschke C, Xiao T, Decembrini S, Swirski S, Kieninger S, Agca C, Kim US, Reynier P, Yu-Wai-Man P, Neidhardt J, Wissinger B. Dominant optic atrophy: Culprit mitochondria in the optic nerve. Prog Retin Eye Res 2021; 83:100935. [PMID: 33340656 DOI: 10.1016/j.preteyeres.2020.100935] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 12/05/2020] [Accepted: 12/09/2020] [Indexed: 12/14/2022]
Abstract
Dominant optic atrophy (DOA) is an inherited mitochondrial disease leading to specific degeneration of retinal ganglion cells (RGCs), thus compromising transmission of visual information from the retina to the brain. Usually, DOA starts during childhood and evolves to poor vision or legal blindness, affecting the central vision, whilst sparing the peripheral visual field. In 20% of cases, DOA presents as syndromic disorder, with secondary symptoms affecting neuronal and muscular functions. Twenty years ago, we demonstrated that heterozygous mutations in OPA1 are the most frequent molecular cause of DOA. Since then, variants in additional genes, whose functions in many instances converge with those of OPA1, have been identified by next generation sequencing. OPA1 encodes a dynamin-related GTPase imported into mitochondria and located to the inner membrane and intermembrane space. The many OPA1 isoforms, resulting from alternative splicing of three exons, form complex homopolymers that structure mitochondrial cristae, and contribute to fusion of the outer membrane, thus shaping the whole mitochondrial network. Moreover, OPA1 is required for oxidative phosphorylation, maintenance of mitochondrial genome, calcium homeostasis and regulation of apoptosis, thus making OPA1 the Swiss army-knife of mitochondria. Understanding DOA pathophysiology requires the understanding of RGC peculiarities with respect to OPA1 functions. Besides the tremendous energy requirements of RGCs to relay visual information from the eye to the brain, these neurons present unique features related to their differential environments in the retina, and to the anatomical transition occurring at the lamina cribrosa, which parallel major adaptations of mitochondrial physiology and shape, in the pre- and post-laminar segments of the optic nerve. Three DOA mouse models, with different Opa1 mutations, have been generated to study intrinsic mechanisms responsible for RGC degeneration, and these have further revealed secondary symptoms related to mitochondrial dysfunctions, mirroring the more severe syndromic phenotypes seen in a subgroup of patients. Metabolomics analyses of cells, mouse organs and patient plasma mutated for OPA1 revealed new unexpected pathophysiological mechanisms related to mitochondrial dysfunction, and biomarkers correlated quantitatively to the severity of the disease. Here, we review and synthesize these data, and propose different approaches for embracing possible therapies to fulfil the unmet clinical needs of this disease, and provide hope to affected DOA patients.
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Affiliation(s)
- Guy Lenaers
- MitoLab Team, UMR CNRS 6015 - INSERM U1083, Institut MitoVasc, Angers University and Hospital, Angers, France.
| | - Albert Neutzner
- Department of Biomedicine, University Hospital Basel, University of Basel, Basel, Switzerland; Department of Ophthalmology University Hospital Basel, University of Basel, Basel, Switzerland.
| | - Yannick Le Dantec
- MitoLab Team, UMR CNRS 6015 - INSERM U1083, Institut MitoVasc, Angers University and Hospital, Angers, France
| | - Christoph Jüschke
- Human Genetics, Faculty VI - School of Medicine and Health Sciences, University of Oldenburg, Oldenburg, Germany
| | - Ting Xiao
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, Center for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Sarah Decembrini
- Department of Biomedicine, University Hospital Basel, University of Basel, Basel, Switzerland; Department of Ophthalmology University Hospital Basel, University of Basel, Basel, Switzerland
| | - Sebastian Swirski
- Human Genetics, Faculty VI - School of Medicine and Health Sciences, University of Oldenburg, Oldenburg, Germany
| | - Sinja Kieninger
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, Center for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Cavit Agca
- Molecular Biology, Genetics and Bioengineering Program, Sabanci University, Istanbul, Turkey; Nanotechnology Research and Application Center (SUNUM), Sabanci University, Istanbul, Turkey
| | - Ungsoo S Kim
- Kim's Eye Hospital, Seoul, South Korea; Cambridge Centre for Brain Repair and MRC Mitochondrial Biology Unit, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK; Cambridge Eye Unit, Addenbrooke's Hospital, Cambridge University Hospitals, Cambridge, UK; Moorfields Eye Hospital, London, UK
| | - Pascal Reynier
- MitoLab Team, UMR CNRS 6015 - INSERM U1083, Institut MitoVasc, Angers University and Hospital, Angers, France; Department of Biochemistry, University Hospital of Angers, Angers, France
| | - Patrick Yu-Wai-Man
- Cambridge Centre for Brain Repair and MRC Mitochondrial Biology Unit, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK; Cambridge Eye Unit, Addenbrooke's Hospital, Cambridge University Hospitals, Cambridge, UK; Moorfields Eye Hospital, London, UK; UCL Institute of Ophthalmology, University College London, London, UK
| | - John Neidhardt
- Human Genetics, Faculty VI - School of Medicine and Health Sciences, University of Oldenburg, Oldenburg, Germany; Research Center Neurosensory Science, University Oldenburg, Oldenburg, Germany.
| | - Bernd Wissinger
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, Center for Ophthalmology, University of Tübingen, Tübingen, Germany.
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Kyriakoudi S, Drousiotou A, Petrou PP. When the Balance Tips: Dysregulation of Mitochondrial Dynamics as a Culprit in Disease. Int J Mol Sci 2021; 22:ijms22094617. [PMID: 33924849 PMCID: PMC8124286 DOI: 10.3390/ijms22094617] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 04/23/2021] [Accepted: 04/25/2021] [Indexed: 12/12/2022] Open
Abstract
Mitochondria are dynamic organelles, the morphology of which is tightly linked to their functions. The interplay between the coordinated events of fusion and fission that are collectively described as mitochondrial dynamics regulates mitochondrial morphology and adjusts mitochondrial function. Over the last few years, accruing evidence established a connection between dysregulated mitochondrial dynamics and disease development and progression. Defects in key components of the machinery mediating mitochondrial fusion and fission have been linked to a wide range of pathological conditions, such as insulin resistance and obesity, neurodegenerative diseases and cancer. Here, we provide an update on the molecular mechanisms promoting mitochondrial fusion and fission in mammals and discuss the emerging association of disturbed mitochondrial dynamics with human disease.
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Affiliation(s)
- Styliana Kyriakoudi
- Department of Biochemical Genetics, The Cyprus Institute of Neurology and Genetics, P.O. Box 23462, Nicosia 1683, Cyprus; (S.K.); (A.D.)
| | - Anthi Drousiotou
- Department of Biochemical Genetics, The Cyprus Institute of Neurology and Genetics, P.O. Box 23462, Nicosia 1683, Cyprus; (S.K.); (A.D.)
- Cyprus School of Molecular Medicine, P.O. Box 23462, Nicosia 1683, Cyprus
| | - Petros P. Petrou
- Department of Biochemical Genetics, The Cyprus Institute of Neurology and Genetics, P.O. Box 23462, Nicosia 1683, Cyprus; (S.K.); (A.D.)
- Cyprus School of Molecular Medicine, P.O. Box 23462, Nicosia 1683, Cyprus
- Correspondence:
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7
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Di Nottia M, Verrigni D, Torraco A, Rizza T, Bertini E, Carrozzo R. Mitochondrial Dynamics: Molecular Mechanisms, Related Primary Mitochondrial Disorders and Therapeutic Approaches. Genes (Basel) 2021; 12:genes12020247. [PMID: 33578638 PMCID: PMC7916359 DOI: 10.3390/genes12020247] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 02/02/2021] [Accepted: 02/04/2021] [Indexed: 02/06/2023] Open
Abstract
Mitochondria do not exist as individual entities in the cell—conversely, they constitute an interconnected community governed by the constant and opposite process of fission and fusion. The mitochondrial fission leads to the formation of smaller mitochondria, promoting the biogenesis of new organelles. On the other hand, following the fusion process, mitochondria appear as longer and interconnected tubules, which enhance the communication with other organelles. Both fission and fusion are carried out by a small number of highly conserved guanosine triphosphatase proteins and their interactors. Disruption of this equilibrium has been associated with several pathological conditions, ranging from cancer to neurodegeneration, and mutations in genes involved in mitochondrial fission and fusion have been reported to be the cause of a subset of neurogenetic disorders.
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Argente-Escrig H, Burns J, Donlevy G, Frasquet M, Cornett K, Sevilla T, Menezes MP. Clinical, Genetic, and Disability Profile of Pediatric Distal Hereditary Motor Neuropathy. Neurology 2020; 96:e423-e432. [PMID: 33067402 DOI: 10.1212/wnl.0000000000011054] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Accepted: 09/01/2020] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To describe the clinical, genetic, and disability profile of pediatric distal hereditary motor neuropathy (dHMN) and to determine the utility of an outcome measure validated for children with Charcot-Marie-Tooth disease (CMT) in assessing disability in this cohort. METHODS We reviewed the clinical, neurophysiologic, and disability data on individuals with dHMN, evaluated before the age of 20 years, at 2 tertiary neuromuscular clinics in Australia and Spain. Disability was assessed annually with the CMT Pediatric Scale (CMTPedS) in a subset of individuals. RESULTS Twenty-two children (13 female) from 19 families were included. Fourteen individuals were symptomatic in the first year of life. Intellectual disability was present in 6 individuals; upper motor neuron signs were seen in 8. Pathogenic variants were found in 9 families, more frequently in BICD2 (BICD2-4, DYNC1H1-2, MFN2-2, GARS-1). A novel pathogenic variant in the GARS gene was detected and characterized phenotypically. Disability was moderate on the CMTPedS (mean [SD] 18.2 [6.3], n = 16), with balance and long jump being the most affected and sensation items and grip strength the least affected. Over 1 year, the CMTPedS total score deteriorated, on average 1.5 points (SD 3.7) or 9% (n = 12), with significant variability in the rate of progression within the cohort. CONCLUSIONS The genetic profile of pediatric dHMN is different from that identified in adult cohorts. This study has identified distinct functional limitations for the CMTPedS in children and adolescents with dHMN.
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Affiliation(s)
- Herminia Argente-Escrig
- From the T.Y. Nelson Department of Neurology and Neurosurgery (M.P.M.), The Children's Hospital at Westmead, NSW; University of Sydney School of Health Sciences & Children's Hospital at Westmead (J.B., G.D., K.C., M.P.M.), Sydney, Australia; Health Research Institute Hospital La Fe (H.A.-E., M.F.) and Department of Neurology (H.A.-E, M.F., T.S.), Hospital Universitari i Politècnic La Fe, Valencia, Spain; Centre for Biomedical Network Research on Rare Diseases-CIBERER (H.A.E., T.S.); and Department of Medicine (T.S.), University of Valencia, Spain
| | - Joshua Burns
- From the T.Y. Nelson Department of Neurology and Neurosurgery (M.P.M.), The Children's Hospital at Westmead, NSW; University of Sydney School of Health Sciences & Children's Hospital at Westmead (J.B., G.D., K.C., M.P.M.), Sydney, Australia; Health Research Institute Hospital La Fe (H.A.-E., M.F.) and Department of Neurology (H.A.-E, M.F., T.S.), Hospital Universitari i Politècnic La Fe, Valencia, Spain; Centre for Biomedical Network Research on Rare Diseases-CIBERER (H.A.E., T.S.); and Department of Medicine (T.S.), University of Valencia, Spain
| | - Gabrielle Donlevy
- From the T.Y. Nelson Department of Neurology and Neurosurgery (M.P.M.), The Children's Hospital at Westmead, NSW; University of Sydney School of Health Sciences & Children's Hospital at Westmead (J.B., G.D., K.C., M.P.M.), Sydney, Australia; Health Research Institute Hospital La Fe (H.A.-E., M.F.) and Department of Neurology (H.A.-E, M.F., T.S.), Hospital Universitari i Politècnic La Fe, Valencia, Spain; Centre for Biomedical Network Research on Rare Diseases-CIBERER (H.A.E., T.S.); and Department of Medicine (T.S.), University of Valencia, Spain
| | - Marina Frasquet
- From the T.Y. Nelson Department of Neurology and Neurosurgery (M.P.M.), The Children's Hospital at Westmead, NSW; University of Sydney School of Health Sciences & Children's Hospital at Westmead (J.B., G.D., K.C., M.P.M.), Sydney, Australia; Health Research Institute Hospital La Fe (H.A.-E., M.F.) and Department of Neurology (H.A.-E, M.F., T.S.), Hospital Universitari i Politècnic La Fe, Valencia, Spain; Centre for Biomedical Network Research on Rare Diseases-CIBERER (H.A.E., T.S.); and Department of Medicine (T.S.), University of Valencia, Spain
| | - Kayla Cornett
- From the T.Y. Nelson Department of Neurology and Neurosurgery (M.P.M.), The Children's Hospital at Westmead, NSW; University of Sydney School of Health Sciences & Children's Hospital at Westmead (J.B., G.D., K.C., M.P.M.), Sydney, Australia; Health Research Institute Hospital La Fe (H.A.-E., M.F.) and Department of Neurology (H.A.-E, M.F., T.S.), Hospital Universitari i Politècnic La Fe, Valencia, Spain; Centre for Biomedical Network Research on Rare Diseases-CIBERER (H.A.E., T.S.); and Department of Medicine (T.S.), University of Valencia, Spain
| | - Teresa Sevilla
- From the T.Y. Nelson Department of Neurology and Neurosurgery (M.P.M.), The Children's Hospital at Westmead, NSW; University of Sydney School of Health Sciences & Children's Hospital at Westmead (J.B., G.D., K.C., M.P.M.), Sydney, Australia; Health Research Institute Hospital La Fe (H.A.-E., M.F.) and Department of Neurology (H.A.-E, M.F., T.S.), Hospital Universitari i Politècnic La Fe, Valencia, Spain; Centre for Biomedical Network Research on Rare Diseases-CIBERER (H.A.E., T.S.); and Department of Medicine (T.S.), University of Valencia, Spain
| | - Manoj P Menezes
- From the T.Y. Nelson Department of Neurology and Neurosurgery (M.P.M.), The Children's Hospital at Westmead, NSW; University of Sydney School of Health Sciences & Children's Hospital at Westmead (J.B., G.D., K.C., M.P.M.), Sydney, Australia; Health Research Institute Hospital La Fe (H.A.-E., M.F.) and Department of Neurology (H.A.-E, M.F., T.S.), Hospital Universitari i Politècnic La Fe, Valencia, Spain; Centre for Biomedical Network Research on Rare Diseases-CIBERER (H.A.E., T.S.); and Department of Medicine (T.S.), University of Valencia, Spain.
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Picci C, Wong VSC, Costa CJ, McKinnon MC, Goldberg DC, Swift M, Alam NM, Prusky GT, Shen S, Kozikowski AP, Willis DE, Langley B. HDAC6 inhibition promotes α-tubulin acetylation and ameliorates CMT2A peripheral neuropathy in mice. Exp Neurol 2020; 328:113281. [PMID: 32147437 DOI: 10.1016/j.expneurol.2020.113281] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 02/24/2020] [Accepted: 03/04/2020] [Indexed: 01/13/2023]
Abstract
Charcot-Marie-Tooth type 2A (CMT2A) peripheral neuropathy, the most common axonal form of CMT, is caused by dominantly inherited point mutations in the Mitofusin 2 (Mfn2) gene. It is characterized by progressive length-dependent degeneration of motor and sensory nerves with corresponding clinical features of motor and sensory impairment. There is no cure for CMT, and therapeutic approaches are limited to physical therapy, orthopedic devices, surgery, and analgesics. In this study we focus on histone deacetylase 6 (HDAC6) as a therapeutic target in a mouse model of mutant MFN2 (MFN2R94Q)-induced CMT2A. We report that these mice display progressive motor and sensory dysfunction as well as a significant decrease in α-tubulin acetylation in distal segments of long peripheral nerves. Treatment with a new, highly selective HDAC6 inhibitor, SW-100, was able to restore α-tubulin acetylation and ameliorate motor and sensory dysfunction when given either prior to or after the onset of symptoms. To confirm HDAC6 is the target for ameliorating the CMT2A phenotype, we show that genetic deletion of Hdac6 in CMT2A mice prevents the development of motor and sensory dysfunction. Our findings suggest α-tubulin acetylation defects in distal parts of nerves as a pathogenic mechanism and HDAC6 as a therapeutic target for CMT2A.
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Affiliation(s)
- Cristina Picci
- The Burke Neurological Institute, White Plains, NY, 10605, USA; Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10065, USA; School of Health, The University of Waikato, Private Bag 3105, Hamilton, New Zealand.
| | - Victor S C Wong
- The Burke Neurological Institute, White Plains, NY, 10605, USA; Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10065, USA
| | | | - Marion C McKinnon
- School of Health, The University of Waikato, Private Bag 3105, Hamilton, New Zealand
| | | | - Michelle Swift
- The Burke Neurological Institute, White Plains, NY, 10605, USA
| | - Nazia M Alam
- The Burke Neurological Institute, White Plains, NY, 10605, USA; Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY 10065, USA
| | - Glen T Prusky
- The Burke Neurological Institute, White Plains, NY, 10605, USA; Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY 10065, USA
| | - Sida Shen
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Alan P Kozikowski
- StarWise Therapeutics LLC, 2020 N Lincoln Park West, Chicago, IL 60614, USA
| | - Dianna E Willis
- The Burke Neurological Institute, White Plains, NY, 10605, USA; Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10065, USA.
| | - Brett Langley
- The Burke Neurological Institute, White Plains, NY, 10605, USA; Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10065, USA; School of Health, The University of Waikato, Private Bag 3105, Hamilton, New Zealand.
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Guerriero S, D'Oria F, Rossetti G, Favale RA, Zoccolella S, Alessio G, Petruzzella V. CMT2A Harboring Mitofusin 2 Mutation with Optic Nerve Atrophy and Normal Visual Acuity. Int Med Case Rep J 2020; 13:41-45. [PMID: 32110117 PMCID: PMC7039061 DOI: 10.2147/imcrj.s237620] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 01/17/2020] [Indexed: 01/20/2023] Open
Abstract
Charcot-Marie-Tooth (CMT) constitutes a group of heterogeneous hereditary motor and sensor neuropathies. Mutations in mitofusin-2 (MFN2) cause CMT type 2A by altering mitochondrial fusion and trafficking along with the axonal microtubule system. In literature patients presenting with CMT2A are reported as having a subacute onset of optic atrophy associated with central scotoma and color vision defects. We report on the clinical and genetic findings in a 40 years-old Caucasian woman presenting with CMT type 2A and MFN2 mutation (c.2258duplT/p.Leu753fs) who presented bilateral progressive optic atrophy with bilateral severe concentric narrowing of the visual field but normal visual acuity and color vision. This is the first report that describes such phenotypical manifestation of an MFN2 mutation suggesting that the molecular mechanisms underlying the mitofusin-2 function alteration at optic nerve need to be investigated further.
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Affiliation(s)
- Silvana Guerriero
- Department of Medical Science, Neuroscience and Sense Organs, University of Bari Aldo Moro, Bari, Italy
| | - Francesco D'Oria
- Department of Medical Science, Neuroscience and Sense Organs, University of Bari Aldo Moro, Bari, Italy
| | - Giacomo Rossetti
- Department of Molecular Biology, University of Geneva, Geneva, Switzerland
| | - Rosa Anna Favale
- Department of Medical Science, Neuroscience and Sense Organs, University of Bari Aldo Moro, Bari, Italy
| | - Stefano Zoccolella
- Department of Medical Science, Neuroscience and Sense Organs, University of Bari Aldo Moro, Bari, Italy
| | - Giovanni Alessio
- Department of Medical Science, Neuroscience and Sense Organs, University of Bari Aldo Moro, Bari, Italy
| | - Vittoria Petruzzella
- Department of Medical Science, Neuroscience and Sense Organs, University of Bari Aldo Moro, Bari, Italy
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Kanemaru K, Ogawa G, Mochizuki H, Nakazato M, Shiomi K. A Sporadic Case of Charcot-Marie-Tooth Disease Type 2 with Left Vocal Fold Palsy due to Mitofusin 2 Mutation. Intern Med 2019; 58:2091-2093. [PMID: 30996168 PMCID: PMC6701995 DOI: 10.2169/internalmedicine.2318-18] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
A 33-year-old Japanese woman was referred for hoarseness. She had been diagnosed with Charcot-Marie-Tooth disease at age 3 and bilateral optic atrophy at age 15. Laryngoscopy revealed left vocal fold palsy. These findings suggested Charcot-Marie-Tooth disease type 2; the diagnosis was confirmed by a mitofusin 2 mutation analysis. Her symptoms remained stable for almost 10 years. Although vocal fold palsy and optic atrophy have been previously reported in patients with mitofusin 2 mutations, detailed clinical information and clinical course have never been documented. These data might contribute to the elucidation of the pathological conditions associated with mitofusin 2 mutations.
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Affiliation(s)
- Kazuki Kanemaru
- Division of Neurology, Respirology, Endocrinology and Metabolism, Department of Internal Medicine, Faculty of Medicine, University of Miyazaki, Japan
| | - Go Ogawa
- Division of Neurology, Respirology, Endocrinology and Metabolism, Department of Internal Medicine, Faculty of Medicine, University of Miyazaki, Japan
| | - Hitoshi Mochizuki
- Division of Neurology, Respirology, Endocrinology and Metabolism, Department of Internal Medicine, Faculty of Medicine, University of Miyazaki, Japan
| | - Masamitsu Nakazato
- Division of Neurology, Respirology, Endocrinology and Metabolism, Department of Internal Medicine, Faculty of Medicine, University of Miyazaki, Japan
| | - Kazutake Shiomi
- Division of Neurology, Respirology, Endocrinology and Metabolism, Department of Internal Medicine, Faculty of Medicine, University of Miyazaki, Japan
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12
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Molecular modelling of mitofusin 2 for a prediction for Charcot-Marie-Tooth 2A clinical severity. Sci Rep 2018; 8:16900. [PMID: 30442897 PMCID: PMC6237821 DOI: 10.1038/s41598-018-35133-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 10/31/2018] [Indexed: 12/30/2022] Open
Abstract
Charcot-Marie-Tooth disease type 2A (CMT2A) is an autosomal dominant neuropathy caused by mutations in the mitofusin 2 gene (MFN2). More than 100 MFN2 gene mutations have been reported so far, with majority located within the GTPase domain encoding region. These domain-specific mutations present wide range of symptoms with differences associated with distinct amino acid substitutions in the same position. Due to the lack of conclusive phenotype-genotype correlation the predictive value of genetic results remains still limited. We have explored whether changes in the protein structure caused by MFN2 mutations can help to explain diseases phenotypes. Using a stable protein model, we evaluated the effect of 26 substitutions on the MFN2 structure and predicted the molecular consequences of such alterations. The observed changes were correlated with clinical features associated with a given mutation. Of all tested mutations positive correlation of molecular modelling with the clinical features reached 73%. Our analysis revealed that molecular modelling of mitofusin 2 mutations is a powerful tool, which predicts associated pathogenic impacts and that these correlate with clinical outcomes. This approach may aid an early diagnosis and prediction of symptoms severity in CMT2A patients.
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Finsterer J, Fiorini AC, Scorza CA, Scorza FA. CMT2 due to homozygous MFN2 variants is a multiorgan mitochondrial disorder. Eur J Paediatr Neurol 2018; 22:889-891. [PMID: 29752145 DOI: 10.1016/j.ejpn.2018.04.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Accepted: 04/24/2018] [Indexed: 10/17/2022]
Affiliation(s)
| | - Ana C Fiorini
- Programa de Estudos Pós-Graduado em Fonoaudiologia, Pontifícia Universidade Católica de São Paulo (PUC-SP), Departamento de Fonoaudiologia, Escola Paulista de Medicina/Universidade Federal de São Paul o (EPM/UNIFESP), São Paulo, Brazil.
| | - Carla A Scorza
- Disciplina de Neurociência, Escola Paulista de Medicina/Universidade Federal de São Paulo/. (EPM/UNIFESP), São Paulo, Brazil.
| | - Fulvio A Scorza
- Disciplina de Neurociência, Escola Paulista de Medicina/Universidade Federal de São Paulo/. (EPM/UNIFESP), São Paulo, Brazil
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Wu R, Fu J, Meng L, Lv H, Wang Z, Yuan Y. Late-onset hereditary sensory and autonomic neuropathy expands the phenotypic spectrum of MFN2-related diseases. Neuropathology 2018; 38:463-467. [PMID: 30011089 DOI: 10.1111/neup.12487] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2018] [Revised: 05/05/2018] [Accepted: 06/04/2018] [Indexed: 12/22/2022]
Abstract
Mutations in the Mitofusin 2 (MFN2) gene have been identified in patients with autosomal dominant axonal motor and sensory neuropathy or Charcot-Marie-Tooth 2A (CMT2A). Here we describe clinical and pathological changes in an adult patient with sporadic hereditary sensory and autonomic neuropathy (HSAN) due to an MFN2 mutation. The patient was a 53-year-old man who had sensory involvement and anhidrosis in all limbs without motor features. The electrophysiological assessment documented severe axonal sensory neuropathy. The sural nerve biopsy confirmed the electrophysiological findings, revealing severe loss of myelinated and unmyelinated fibers with regeneration clusters. Genetic analysis revealed the previously identified mutation c.776 G > A in MFN2. Our report expands the phenotypic spectrum of MFN2-related diseases. Sequencing of MFN2 should be considered in all patients presenting with late-onset HSAN.
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Affiliation(s)
- Rui Wu
- Department of Neurology, Peking University First Hospital, Beijing, China
| | - Jun Fu
- Department of Neurology, Peking University First Hospital, Beijing, China
| | - Lingchao Meng
- Department of Neurology, Peking University First Hospital, Beijing, China
| | - He Lv
- Department of Neurology, Peking University First Hospital, Beijing, China
| | - Zhaoxia Wang
- Department of Neurology, Peking University First Hospital, Beijing, China
| | - Yun Yuan
- Department of Neurology, Peking University First Hospital, Beijing, China
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Bagli E, Zikou AK, Agnantis N, Kitsos G. Mitochondrial Membrane Dynamics and Inherited Optic Neuropathies. ACTA ACUST UNITED AC 2018; 31:511-525. [PMID: 28652416 DOI: 10.21873/invivo.11090] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 04/14/2017] [Accepted: 04/19/2017] [Indexed: 12/12/2022]
Abstract
Inherited optic neuropathies are a genetically diverse group of disorders mainly characterized by visual loss and optic atrophy. Since the first recognition of Leber's hereditary optic neuropathy, several genetic defects altering primary mitochondrial respiration have been proposed to contribute to the development of syndromic and non-syndromic optic neuropathies. Moreover, the genomics and imaging revolution in the past decade has increased diagnostic efficiency and accuracy, allowing recognition of a link between mitochondrial dynamics machinery and a broad range of inherited neurodegenerative diseases involving the optic nerve. Mutations of novel genes modifying mainly the balance between mitochondrial fusion and fission have been shown to lead to overlapping clinical phenotypes ranging from isolated optic atrophy to severe, sometimes lethal multisystem disorders, and are reviewed herein. Given the particular vulnerability of retinal ganglion cells to mitochondrial dysfunction, the accessibility of the eye as a part of the central nervous system and improvements in technical imaging concerning assessment of the retinal nerve fiber layer, optic nerve evaluation becomes critical - even in asymptomatic patients - for correct diagnosis, understanding and early treatment of these complex and enigmatic clinical entities.
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Affiliation(s)
- Eleni Bagli
- Institute of Molecular Biology and Biotechnology-FORTH, Division of Biomedical Research, Ioannina, Greece.,Department of Ophthalmology, University of Ioannina, Ioannina, Greece
| | - Anastasia K Zikou
- Department of Clinical Radiology, University of Ioannina, Ioannina, Greece
| | - Niki Agnantis
- Department of Pathology, University of Ioannina, Ioannina, Greece
| | - Georgios Kitsos
- Department of Ophthalmology, University of Ioannina, Ioannina, Greece
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Jiang S, Nandy P, Wang W, Ma X, Hsia J, Wang C, Wang Z, Niu M, Siedlak SL, Torres S, Fujioka H, Xu Y, Lee HG, Perry G, Liu J, Zhu X. Mfn2 ablation causes an oxidative stress response and eventual neuronal death in the hippocampus and cortex. Mol Neurodegener 2018; 13:5. [PMID: 29391029 PMCID: PMC5796581 DOI: 10.1186/s13024-018-0238-8] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 01/24/2018] [Indexed: 12/20/2022] Open
Abstract
Background Mitochondria are the organelles responsible for energy metabolism and have a direct impact on neuronal function and survival. Mitochondrial abnormalities have been well characterized in Alzheimer Disease (AD). It is believed that mitochondrial fragmentation, due to impaired fission and fusion balance, likely causes mitochondrial dysfunction that underlies many aspects of neurodegenerative changes in AD. Mitochondrial fission and fusion proteins play a major role in maintaining the health and function of these important organelles. Mitofusion 2 (Mfn2) is one such protein that regulates mitochondrial fusion in which mutations lead to the neurological disease. Methods To examine whether and how impaired mitochondrial fission/fusion balance causes neurodegeneration in AD, we developed a transgenic mouse model using the CAMKII promoter to knockout neuronal Mfn2 in the hippocampus and cortex, areas significantly affected in AD. Results Electron micrographs of neurons from these mice show swollen mitochondria with cristae damage and mitochondria membrane abnormalities. Over time the Mfn2 cKO model demonstrates a progression of neurodegeneration via mitochondrial morphological changes, oxidative stress response, inflammatory changes, and loss of MAP2 in dendrites, leading to severe and selective neuronal death. In this model, hippocampal CA1 neurons were affected earlier and resulted in nearly total loss, while in the cortex, progressive neuronal death was associated with decreased cortical size. Conclusions Overall, our findings indicate that impaired mitochondrial fission and fusion balance can cause many of the neurodegenerative changes and eventual neuron loss that characterize AD in the hippocampus and cortex which makes it a potential target for treatment strategies for AD. Electronic supplementary material The online version of this article (10.1186/s13024-018-0238-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sirui Jiang
- Department of Pathology, Case Western Reserve University, 2103 Cornell Road, Cleveland, OH, USA
| | - Priya Nandy
- Department of Pathology, Case Western Reserve University, 2103 Cornell Road, Cleveland, OH, USA
| | - Wenzhang Wang
- Department of Pathology, Case Western Reserve University, 2103 Cornell Road, Cleveland, OH, USA
| | - Xiaopin Ma
- Department of Pathology, Case Western Reserve University, 2103 Cornell Road, Cleveland, OH, USA
| | - Jeffrey Hsia
- Department of Pathology, Case Western Reserve University, 2103 Cornell Road, Cleveland, OH, USA
| | - Chunyu Wang
- Department of Neurology, the second Xiangya Hospital, Central South University, Changsha, Hunan, People's Republic of China
| | - Zhenlian Wang
- School of Pharmaceutical Engineering & Life Sciences, Changzhou University, Changzhou, Jiangsu, 213164, China
| | - Mengyue Niu
- Department of Neurology & Institute of Neurology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Sandra L Siedlak
- Department of Pathology, Case Western Reserve University, 2103 Cornell Road, Cleveland, OH, USA
| | - Sandy Torres
- Department of Pathology, Case Western Reserve University, 2103 Cornell Road, Cleveland, OH, USA
| | - Hisashi Fujioka
- Electron Microscopy Core Facility, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Ying Xu
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, State University of New York at Buffalo, Buffalo, NY, 14222, USA
| | - Hyoung-Gon Lee
- Department of Biology, The University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, 78249, USA
| | - George Perry
- Department of Biology, The University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, 78249, USA
| | - Jun Liu
- Department of Neurology & Institute of Neurology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Xiongwei Zhu
- Department of Pathology, Case Western Reserve University, 2103 Cornell Road, Cleveland, OH, USA.
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17
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Characterization of Charcot-Marie-Tooth optic neuropathy. J Neurol 2017; 264:2431-2435. [PMID: 29063243 DOI: 10.1007/s00415-017-8645-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 10/10/2017] [Accepted: 10/11/2017] [Indexed: 10/18/2022]
Abstract
Varying degrees of optic neuropathy can be seen in patients with Charcot-Marie-Tooth (CMT) disease. To define and characterize the extent of optic neuropathy in patients with CMT2A and CMT1A, two patients from both sub-classifications were evaluated. All patients underwent complete neuro-ophthalmic examinations, and optical coherence (OCT) measurements of the retinal nerve fiber layer (RNFL) and ganglion cell layer complex (GCC) were obtained, along with pattern visual evoked potential (VEP) and pattern electroretinogram (ERG) recordings. RNFL thickness measurements were decreased in both patients with CMT2A, and normal in both patients with CMT1A. GCC measurements were decreased in both patients with CMT2A, mildly decreased in one patient with CMT1A and normal in the second CMT1A patient. VEP latencies were delayed in one patient with CMT2A and one patient with CMT1A. VEP latencies were immeasurable in the other CMT2A patient and not obtained in the second CMT1A patient. Pattern ERG P50-N95 amplitudes were decreased in both patients with CMT2A and normal in one patient with CMT1A. The pattern ERG was immeasurable in the second patient with CMT1A. The pattern of RNFL and GCC thinning in CMT2A with optic neuropathy, a subset of HMSN VI, closely resembles that seen in other mitochondrial optic neuropathies.
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18
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Weis J, Claeys KG, Roos A, Azzedine H, Katona I, Schröder JM, Senderek J. Towards a functional pathology of hereditary neuropathies. Acta Neuropathol 2017; 133:493-515. [PMID: 27896434 DOI: 10.1007/s00401-016-1645-y] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 11/10/2016] [Accepted: 11/13/2016] [Indexed: 12/11/2022]
Abstract
A growing number of hereditary neuropathies have been assigned to causative gene defects in recent years. The study of human nerve biopsy samples has contributed substantially to the discovery of many of these neuropathy genes. Genotype-phenotype correlations based on peripheral nerve pathology have provided a comprehensive picture of the consequences of these mutations. Intriguingly, several gene defects lead to distinguishable lesion patterns that can be studied in nerve biopsies. These characteristic features include the loss of certain nerve fiber populations and a large spectrum of distinct structural changes of axons, Schwann cells and other components of peripheral nerves. In several instances the lesion patterns are directly or indirectly linked to the known functions of the mutated gene. The present review is designed to provide an overview on these characteristic patterns. It also considers other aspects important for the manifestation and pathology of hereditary neuropathies including the role of inflammation, effects of chemotherapeutic agents and alterations detectable in skin biopsies.
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Affiliation(s)
- Joachim Weis
- Institute of Neuropathology, RWTH Aachen University Medical School, Pauwelsstr. 30, 52074, Aachen, Germany.
| | - Kristl G Claeys
- Institute of Neuropathology, RWTH Aachen University Medical School, Pauwelsstr. 30, 52074, Aachen, Germany
- Department of Neurology, RWTH Aachen University Medical School, Pauwelsstr. 30, 52074, Aachen, Germany
- Department of Neurology, University Hospitals Leuven and University of Leuven (KU Leuven), Leuven, Belgium
| | - Andreas Roos
- Institute of Neuropathology, RWTH Aachen University Medical School, Pauwelsstr. 30, 52074, Aachen, Germany
- Leibniz-Institut für Analytische Wissenschaften-ISAS-e.V., Otto-Hahn-Str. 6b, 44227, Dortmund, Germany
| | - Hamid Azzedine
- Institute of Neuropathology, RWTH Aachen University Medical School, Pauwelsstr. 30, 52074, Aachen, Germany
| | - Istvan Katona
- Institute of Neuropathology, RWTH Aachen University Medical School, Pauwelsstr. 30, 52074, Aachen, Germany
| | - J Michael Schröder
- Institute of Neuropathology, RWTH Aachen University Medical School, Pauwelsstr. 30, 52074, Aachen, Germany
| | - Jan Senderek
- Friedrich-Baur-Institute, Department of Neurology, Ludwig-Maximilians-University, Ziemssenstr. 1a, 80336, Munich, Germany.
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