1
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Maltby CJ, Krans A, Grudzien SJ, Palacios Y, Muiños J, Suárez A, Asher M, Willey S, Van Deynze K, Mumm C, Boyle AP, Cortese A, Ndayisaba A, Khurana V, Barmada SJ, Dijkstra AA, Todd PK. AAGGG repeat expansions trigger RFC1-independent synaptic dysregulation in human CANVAS neurons. SCIENCE ADVANCES 2024; 10:eadn2321. [PMID: 39231235 PMCID: PMC11373605 DOI: 10.1126/sciadv.adn2321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Accepted: 07/30/2024] [Indexed: 09/06/2024]
Abstract
Cerebellar ataxia with neuropathy and vestibular areflexia syndrome (CANVAS) is a recessively inherited neurodegenerative disorder caused by intronic biallelic, nonreference CCCTT/AAGGG repeat expansions within RFC1. To investigate how these repeats cause disease, we generated patient induced pluripotent stem cell-derived neurons (iNeurons). CCCTT/AAGGG repeat expansions do not alter neuronal RFC1 splicing, expression, or DNA repair pathway function. In reporter assays, AAGGG repeats are translated into pentapeptide repeat proteins. However, these proteins and repeat RNA foci were not detected in iNeurons, and overexpression of these repeats failed to induce neuronal toxicity. CANVAS iNeurons exhibit defects in neuronal development and diminished synaptic connectivity that is rescued by CRISPR deletion of a single expanded AAGGG allele. These deficits were neither replicated by RFC1 knockdown in control iNeurons nor rescued by RFC1 reprovision in CANVAS iNeurons. These findings support a repeat-dependent but RFC1 protein-independent cause of neuronal dysfunction in CANVAS, with implications for therapeutic development in this currently untreatable condition.
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Affiliation(s)
- Connor J Maltby
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Amy Krans
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- Ann Arbor Veterans Administration Healthcare, Ann Arbor, MI, USA
| | - Samantha J Grudzien
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, USA
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA
| | - Yomira Palacios
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- Postbaccalaureate Research Education Program, University of Michigan, Ann Arbor, MI, USA
| | - Jessica Muiños
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- UM SMART Undergraduate Summer Program, University of Michigan, Ann Arbor, MI, USA
| | - Andrea Suárez
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- Postbaccalaureate Research Education Program, University of Michigan, Ann Arbor, MI, USA
| | - Melissa Asher
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Sydney Willey
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, USA
| | - Kinsey Van Deynze
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA
| | - Camille Mumm
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, USA
| | - Alan P Boyle
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA
| | - Andrea Cortese
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
- Department of Brain and Behaviour Sciences, University of Pavia, Pavia 27100, Italy
| | - Alain Ndayisaba
- Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Vikram Khurana
- Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
- Harvard Stem Cell Institute, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Sami J Barmada
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Anke A Dijkstra
- Department of Pathology, Amsterdam UMC, Amsterdam Neuroscience, Amsterdam, Netherlands
- Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, Netherlands
| | - Peter K Todd
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- Ann Arbor Veterans Administration Healthcare, Ann Arbor, MI, USA
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2
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Shukla S, Gupta K, Singh K, Mishra A, Kumar A. An Updated Canvas of the RFC1-mediated CANVAS (Cerebellar Ataxia, Neuropathy and Vestibular Areflexia Syndrome). Mol Neurobiol 2024:10.1007/s12035-024-04307-0. [PMID: 38898197 DOI: 10.1007/s12035-024-04307-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Accepted: 06/13/2024] [Indexed: 06/21/2024]
Abstract
Proliferation of specific nucleotide sequences within the coding and non-coding regions of numerous genes has been implicated in approximately 40 neurodegenerative disorders. Cerebellar ataxia, neuropathy and vestibular areflexia syndrome (CANVAS), a neurodegenerative disorder, is distinguished by a pathological triad of sensory neuropathy, bilateral vestibular areflexia and cerebellar impairments. It manifests in adults gradually and is autosomal recessive and multi-system ataxia. Predominantly, CANVAS is associated with biallelic AAGGG repeat expansions in intron 2 of the RFC1 gene. Although various motifs have been identified, only a subset induces pathological consequences, by forming stable secondary structures that disrupt gene functions both in vitro and in vivo. The pathogenesis of CANVAS remains a subject of intensive research, yet its precise mechanisms remain elusive. Herein, we aim to comprehensively review the epidemiology, clinical ramifications, molecular mechanisms, genetics, and potential therapeutics in light of the current findings, extending an overview of the most significant research on CANVAS.
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Affiliation(s)
- Sakshi Shukla
- Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Simrol, Indore, 453552, India
| | - Kanav Gupta
- Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Simrol, Indore, 453552, India
| | - Krishna Singh
- Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Simrol, Indore, 453552, India
| | - Amit Mishra
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology, Jodhpur, Rajasthan, 342037, India
| | - Amit Kumar
- Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Simrol, Indore, 453552, India.
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3
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Borsche M, Thomsen M, Szmulewicz DJ, Lübbers B, Hinrichs F, Lockhart PJ, Lohmann K, Helmchen C, Brüggemann N. Bilateral vestibulopathy in RFC1-positive CANVAS is distinctly different compared to FGF14-linked spinocerebellar ataxia 27B. J Neurol 2024; 271:1023-1027. [PMID: 37861706 PMCID: PMC10827886 DOI: 10.1007/s00415-023-12050-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 10/06/2023] [Accepted: 10/06/2023] [Indexed: 10/21/2023]
Affiliation(s)
- Max Borsche
- Institute of Neurogenetics, University of Lübeck and University Hospital Schleswig-Holstein, Campus Lübeck, Lübeck, Germany
- Department of Neurology, University of Lübeck and University Hospital Schleswig-Holstein, Campus Lübeck, Ratzeburger Allee 160, 23538, Lübeck, Germany
| | - Mirja Thomsen
- Institute of Neurogenetics, University of Lübeck and University Hospital Schleswig-Holstein, Campus Lübeck, Lübeck, Germany
| | - David J Szmulewicz
- Cerebellar Ataxia Clinic, Eye and Ear Hospital, Melbourne, VIC, Australia
- The Bionics Institute, University of Melbourne, Melbourne, VIC, Australia
| | - Bente Lübbers
- Institute of Neurogenetics, University of Lübeck and University Hospital Schleswig-Holstein, Campus Lübeck, Lübeck, Germany
- Department of Neurology, University of Lübeck and University Hospital Schleswig-Holstein, Campus Lübeck, Ratzeburger Allee 160, 23538, Lübeck, Germany
| | - Frauke Hinrichs
- Institute of Neurogenetics, University of Lübeck and University Hospital Schleswig-Holstein, Campus Lübeck, Lübeck, Germany
| | - Paul J Lockhart
- Bruce Lefroy Centre, Murdoch Children's Research Institute, Parkville, VIC, Australia
- Department of Paediatrics, University of Melbourne, Parkville, VIC, Australia
| | - Katja Lohmann
- Institute of Neurogenetics, University of Lübeck and University Hospital Schleswig-Holstein, Campus Lübeck, Lübeck, Germany
| | - Christoph Helmchen
- Department of Neurology, University of Lübeck and University Hospital Schleswig-Holstein, Campus Lübeck, Ratzeburger Allee 160, 23538, Lübeck, Germany
| | - Norbert Brüggemann
- Department of Neurology, University of Lübeck and University Hospital Schleswig-Holstein, Campus Lübeck, Ratzeburger Allee 160, 23538, Lübeck, Germany.
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4
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Lobo CC, Wertheimer GS, Schmitt GS, Matos PC, Rezende TJ, Silva JM, Borba FC, Lima FD, Martinez AR, Barsottini OG, Pedroso JL, Marques W, França MC. Cranial Nerve Thinning Distinguishes RFC1-Related Disorder from Other Late-Onset Ataxias. Mov Disord Clin Pract 2024; 11:45-52. [PMID: 38291837 PMCID: PMC10828611 DOI: 10.1002/mdc3.13930] [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: 06/22/2023] [Revised: 10/11/2023] [Accepted: 11/04/2023] [Indexed: 02/01/2024] Open
Abstract
BACKGROUND RFC1-related disorder (RFC1/CANVAS) shares clinical features with other late-onset ataxias, such as spinocerebellar ataxias (SCA) and multiple system atrophy cerebellar type (MSA-C). Thinning of cranial nerves V (CNV) and VIII (CNVIII) has been reported in magnetic resonance imaging (MRI) scans of RFC1/CANVAS, but its specificity remains unclear. OBJECTIVES To assess the usefulness of CNV and CNVIII thinning to differentiate RFC1/CANVAS from SCA and MSA-C. METHODS Seventeen individuals with RFC1/CANVAS, 57 with SCA (types 2, 3 and 6), 11 with MSA-C and 15 healthy controls were enrolled. The Balanced Fast Field Echo sequence was used for assessment of cranial nerves. Images were reviewed by a neuroradiologist, who classified these nerves as atrophic or normal, and subsequently the CNV was segmented manually by an experienced neurologist. Both assessments were blinded to patient and clinical data. Non-parametric tests were used to assess between-group comparisons. RESULTS Atrophy of CNV and CNVIII, both alone and in combination, was significantly more frequent in the RFC1/CANVAS group than in healthy controls and all other ataxia groups. Atrophy of CNV had the highest sensitivity (82%) and combined CNV and CNVIII atrophy had the best specificity (92%) for diagnosing RFC1/CANVAS. In the quantitative analyses, CNV was significantly thinner in the RFC1/CANVAS group relative to all other groups. The cutoff CNV diameter that best identified RFC1/CANVAS was ≤2.2 mm (AUC = 0.91; sensitivity 88.2%, specificity 95.6%). CONCLUSION MRI evaluation of CNV and CNVIII using a dedicated sequence is an easy-to-use tool that helps to distinguish RFC1/CANVAS from SCA and MSA-C.
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Affiliation(s)
- Camila C. Lobo
- Department of Neurology, School of Medical SciencesUniversity of Campinas (UNICAMP)CampinasBrazil
| | | | - Gabriel S. Schmitt
- Department of Neurology, School of Medical SciencesUniversity of Campinas (UNICAMP)CampinasBrazil
| | - Paula C.A.A.P. Matos
- Department of Neurology and Neurosurgery, School of MedicineFederal University of São Paulo (UNIFESP)São PauloBrazil
| | - Thiago J.R. Rezende
- Department of Neurology, School of Medical SciencesUniversity of Campinas (UNICAMP)CampinasBrazil
| | - Joyce M. Silva
- Department of Neurology, School of Medical SciencesUniversity of Campinas (UNICAMP)CampinasBrazil
| | - Fabrício C. Borba
- Department of Neurology, School of Medical SciencesUniversity of Campinas (UNICAMP)CampinasBrazil
| | - Fabrício D. Lima
- Department of Neurology, School of Medical SciencesUniversity of Campinas (UNICAMP)CampinasBrazil
| | - Alberto R.M. Martinez
- Department of Neurology, School of Medical SciencesUniversity of Campinas (UNICAMP)CampinasBrazil
| | - Orlando G.P. Barsottini
- Department of Neurology and Neurosurgery, School of MedicineFederal University of São Paulo (UNIFESP)São PauloBrazil
| | - José Luiz Pedroso
- Department of Neurology and Neurosurgery, School of MedicineFederal University of São Paulo (UNIFESP)São PauloBrazil
| | - Wilson Marques
- Department of Neurosciences, School of MedicineUniversity of São Paulo at Ribeirão Preto (USP‐RP)Ribeirão PretoBrazil
| | - Marcondes C. França
- Department of Neurology, School of Medical SciencesUniversity of Campinas (UNICAMP)CampinasBrazil
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5
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van Stiphout L, Szmulewicz DJ, Guinand N, Fornos AP, Van Rompaey V, van de Berg R. Bilateral vestibulopathy: a clinical update and proposed diagnostic algorithm. Front Neurol 2023; 14:1308485. [PMID: 38178884 PMCID: PMC10766383 DOI: 10.3389/fneur.2023.1308485] [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: 10/06/2023] [Accepted: 11/29/2023] [Indexed: 01/06/2024] Open
Abstract
Bilateral vestibulopathy (BVP) is characterized by its heterogeneous and chronic nature with various clinical presentations and multiple etiologies. This current narrative review reflects on the main insights and developments regarding clinical presentation. In addition, it proposes a new diagnostic algorithm, and describes available and potential future therapeutic modalities.
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Affiliation(s)
- Lisa van Stiphout
- Department of Otorhinolaryngology and Head and Neck Surgery, Division of Balance Disorders, School for Mental Health and Neuroscience, Maastricht University Medical Center, Maastricht, Netherlands
| | - David J. Szmulewicz
- Royal Victorian Eye and Ear Hospital, University of Melbourne, Melbourne, VIC, Australia
- Bionics Institute, Melbourne, VIC, Australia
| | - Nils Guinand
- Service of Otorhinolaryngology Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals, Geneva, Switzerland
| | - Angélica Pérez Fornos
- Service of Otorhinolaryngology Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals, Geneva, Switzerland
| | - Vincent Van Rompaey
- Department of Otorhinolaryngology, Head and Neck Surgery, Antwerp University Hospital, Antwerp, Belgium
- Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Raymond van de Berg
- Department of Otorhinolaryngology and Head and Neck Surgery, Division of Balance Disorders, School for Mental Health and Neuroscience, Maastricht University Medical Center, Maastricht, Netherlands
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6
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Maltby CJ, Krans A, Grudzien SJ, Palacios Y, Muiños J, Suárez A, Asher M, Khurana V, Barmada SJ, Dijkstra AA, Todd PK. AAGGG repeat expansions trigger RFC1-independent synaptic dysregulation in human CANVAS Neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.13.571345. [PMID: 38168171 PMCID: PMC10760133 DOI: 10.1101/2023.12.13.571345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Cerebellar ataxia with neuropathy and vestibular areflexia syndrome (CANVAS) is a late onset, recessively inherited neurodegenerative disorder caused by biallelic, non-reference pentameric AAGGG(CCCTT) repeat expansions within the second intron of replication factor complex subunit 1 (RFC1). To investigate how these repeats cause disease, we generated CANVAS patient induced pluripotent stem cell (iPSC) derived neurons (iNeurons) and utilized calcium imaging and transcriptomic analysis to define repeat-elicited gain-of-function and loss-of-function contributions to neuronal toxicity. AAGGG repeat expansions do not alter neuronal RFC1 splicing, expression, or DNA repair pathway functions. In reporter assays, AAGGG repeats are translated into pentapeptide repeat proteins that selectively accumulate in CANVAS patient brains. However, neither these proteins nor repeat RNA foci were detected in iNeurons, and overexpression of these repeats in isolation did not induce neuronal toxicity. CANVAS iNeurons exhibit defects in neuronal development and diminished synaptic connectivity that is rescued by CRISPR deletion of a single expanded allele. These phenotypic deficits were not replicated by knockdown of RFC1 in control neurons and were not rescued by ectopic expression of RFC1. These findings support a repeat-dependent but RFC1-independent cause of neuronal dysfunction in CANVAS, with important implications for therapeutic development in this currently untreatable condition.
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Affiliation(s)
- Connor J. Maltby
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Amy Krans
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- Ann Arbor Veterans Administration Healthcare, Ann Arbor, MI, USA
| | - Samantha J. Grudzien
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, USA
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA
| | - Yomira Palacios
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- Postbaccalaureate Research Education Program, University of Michigan, Ann Arbor, MI, USA
| | - Jessica Muiños
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- UM SMART Undergraduate Summer Program, University of Michigan, Ann Arbor, MI, USA
| | - Andrea Suárez
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- Postbaccalaureate Research Education Program, University of Michigan, Ann Arbor, MI, USA
| | - Melissa Asher
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Vikram Khurana
- Department of Neurology, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Sami J. Barmada
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Anke A. Dijkstra
- Department of Pathology, Amsterdam UMC, Amsterdam Neuroscience, Amsterdam, The Netherlands
- Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Peter K. Todd
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- Ann Arbor Veterans Administration Healthcare, Ann Arbor, MI, USA
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7
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Halmágyi GM, Akdal G, Welgampola MS, Wang C. Neurological update: neuro-otology 2023. J Neurol 2023; 270:6170-6192. [PMID: 37592138 PMCID: PMC10632253 DOI: 10.1007/s00415-023-11922-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2023] [Accepted: 08/01/2023] [Indexed: 08/19/2023]
Abstract
Much has changed since our last review of recent advances in neuro-otology 7 years ago. Unfortunately there are still not many practising neuro-otologists, so that most patients with vestibular problems need, in the first instance, to be evaluated and treated by neurologists whose special expertise is not neuro-otology. The areas we consider here are mostly those that almost any neurologist should be able to start managing: acute spontaneous vertigo in the Emergency Room-is it vestibular neuritis or posterior circulation stroke; recurrent spontaneous vertigo in the office-is it vestibular migraine or Meniere's disease and the most common vestibular problem of all-benign positional vertigo. Finally we consider the future: long-term vestibular monitoring and the impact of machine learning on vestibular diagnosis.
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Affiliation(s)
- Gábor M Halmágyi
- Neurology Department, Royal Prince Alfred Hospital, Sydney, Australia.
- Central Clinical School, University of Sydney, Sydney, Australia.
| | - Gülden Akdal
- Neurology Department, Dokuz Eylül University Hospital, Izmir, Turkey
- Neurosciences Department, Dokuz Eylül University Hospital, Izmir, Turkey
| | - Miriam S Welgampola
- Neurology Department, Royal Prince Alfred Hospital, Sydney, Australia
- Central Clinical School, University of Sydney, Sydney, Australia
| | - Chao Wang
- Neurology Department, Royal Prince Alfred Hospital, Sydney, Australia
- Central Clinical School, University of Sydney, Sydney, Australia
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8
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Roberts LJ, Szmulewicz DJ. A patient with neuropathy and ataxia: what do I have to consider? Curr Opin Neurol 2023; 36:382-387. [PMID: 37639448 DOI: 10.1097/wco.0000000000001200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
PURPOSE OF REVIEW An increasing number of peripheral neuro(no)pathies are identified as involving other components of the neurological system, particularly those that further impair balance. Here we aim to outline an evidence-based approach to the diagnosis of patients who present with a somatosensory disorder which also involves at least one other area of neurological impairment such as the vestibular, auditory, or cerebellar systems. RECENT FINDINGS Detailed objective investigation of patients who present with sensory impairment, particularly where the degree of imbalance is greater than would be expected, aids the accurate diagnosis of genetic, autoimmune, metabolic, and toxic neurological disease. SUMMARY Diagnosis and management of complex somatosensory disorders benefit from investigation which extends beyond the presenting sensory impairment.
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Affiliation(s)
- Leslie J Roberts
- Neurophysiology Department, Department of Neurology & Neurological Research, St Vincent's Hospital, Department of Medicine, the University of Melbourne
| | - David J Szmulewicz
- Balance Disorders and Ataxia Service, Eye and Ear Hospital
- Bionics Institute, 384-388 Albert Street, East Melbourne, Victoria, Australia
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9
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Traschütz A, Heindl F, Bilal M, Hartmann AM, Dufke C, Riess O, Zwergal A, Rujescu D, Haack T, Synofzik M, Strupp M. Frequency and Phenotype of RFC1 Repeat Expansions in Bilateral Vestibulopathy. Neurology 2023; 101:e1001-e1013. [PMID: 37460231 PMCID: PMC10491447 DOI: 10.1212/wnl.0000000000207553] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 05/08/2023] [Indexed: 09/06/2023] Open
Abstract
BACKGROUND AND OBJECTIVES Bilateral vestibulopathy (BVP) is a chronic debilitating neurologic disorder with no monogenic cause established so far despite familiar presentations. We hypothesized that replication factor complex subunit 1 (RFC1) repeat expansions might present a recurrent monogenic cause of BVP. METHODS The study involved RFC1 screening and in-depth neurologic, vestibulo-oculomotor, and disease evolution phenotyping of 168 consecutive patients with idiopathic at least "probable BVP" from a tertiary referral center for balance disorders, with127 of them meeting current diagnostic criteria of BVP (Bárány Society Classification). RESULTS Biallelic AAGGG repeat expansions in RFC1 were identified in 10/127 patients (8%) with BVP and 1/41 with probable BVP. Heterozygous expansions in 10/127 patients were enriched compared with those in reference populations. RFC1-related BVP manifested at a median age of 60 years (range 34-72 years) and co-occurred predominantly with mild polyneuropathy (10/11). Additional cerebellar involvement (7/11) was subtle and limited to oculomotor signs in early stages, below recognition of classic cerebellar ataxia, neuropathy, and vestibular areflexia syndrome. Clear dysarthria, appendicular ataxia, or cerebellar atrophy developed 6-8 years after onset. Dysarthria, absent patellar reflexes, and downbeat nystagmus best discriminated RFC1-positive BVP from RFC1-negative BVP, but neither sensory symptoms nor fine motor problems. Video head impulse gains of patients with RFC1-positive BVP were lower relative to those of patients with RFC1-negative BVP and decreased until 10 years disease duration, indicating a potential progression and outcome marker for RFC1-disease. DISCUSSION This study identifies RFC1 as the first-and frequent-monogenic cause of BVP. It characterizes RFC1-related BVP as part of the multisystemic evolution of RFC1 spectrum disease, with implications for designing natural history studies and future treatment trials. CLASSIFICATION OF EVIDENCE This study provides Class II evidence that RFC1 repeat expansions cause BVP.
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Affiliation(s)
- Andreas Traschütz
- From the Research Division Translational Genomics of Neurodegenerative Diseases (A.T., M. Synofzik), Hertie-Institute for Clinical Brain Research and Center of Neurology, and German Center for Neurodegenerative Diseases (DZNE) (A.T., M. Synofzik), University of Tübingen; Department of Neurology and German Center for Vertigo and Balance Disorders (F.H., A.Z., M. Strupp), University Hospital, Ludwig-Maximilians University, Munich, Germany; Department of Biochemistry (M.B.), Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan; Institute of Medical Genetics and Applied Genomics (A.M.H., D.R.), University of Tübingen, Germany; Department of Psychiatry and Psychotherapy (M.B., C.D., O.R., T.H.), Comprehensive Center for Clinical Neurosciences and Mental Health (C3NMH), Medical University of Vienna, Austria; and Center for Rare Diseases (C.D., O.R., T.H.), University of Tübingen, Germany
| | - Felix Heindl
- From the Research Division Translational Genomics of Neurodegenerative Diseases (A.T., M. Synofzik), Hertie-Institute for Clinical Brain Research and Center of Neurology, and German Center for Neurodegenerative Diseases (DZNE) (A.T., M. Synofzik), University of Tübingen; Department of Neurology and German Center for Vertigo and Balance Disorders (F.H., A.Z., M. Strupp), University Hospital, Ludwig-Maximilians University, Munich, Germany; Department of Biochemistry (M.B.), Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan; Institute of Medical Genetics and Applied Genomics (A.M.H., D.R.), University of Tübingen, Germany; Department of Psychiatry and Psychotherapy (M.B., C.D., O.R., T.H.), Comprehensive Center for Clinical Neurosciences and Mental Health (C3NMH), Medical University of Vienna, Austria; and Center for Rare Diseases (C.D., O.R., T.H.), University of Tübingen, Germany
| | - Muhammad Bilal
- From the Research Division Translational Genomics of Neurodegenerative Diseases (A.T., M. Synofzik), Hertie-Institute for Clinical Brain Research and Center of Neurology, and German Center for Neurodegenerative Diseases (DZNE) (A.T., M. Synofzik), University of Tübingen; Department of Neurology and German Center for Vertigo and Balance Disorders (F.H., A.Z., M. Strupp), University Hospital, Ludwig-Maximilians University, Munich, Germany; Department of Biochemistry (M.B.), Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan; Institute of Medical Genetics and Applied Genomics (A.M.H., D.R.), University of Tübingen, Germany; Department of Psychiatry and Psychotherapy (M.B., C.D., O.R., T.H.), Comprehensive Center for Clinical Neurosciences and Mental Health (C3NMH), Medical University of Vienna, Austria; and Center for Rare Diseases (C.D., O.R., T.H.), University of Tübingen, Germany
| | - Annette M Hartmann
- From the Research Division Translational Genomics of Neurodegenerative Diseases (A.T., M. Synofzik), Hertie-Institute for Clinical Brain Research and Center of Neurology, and German Center for Neurodegenerative Diseases (DZNE) (A.T., M. Synofzik), University of Tübingen; Department of Neurology and German Center for Vertigo and Balance Disorders (F.H., A.Z., M. Strupp), University Hospital, Ludwig-Maximilians University, Munich, Germany; Department of Biochemistry (M.B.), Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan; Institute of Medical Genetics and Applied Genomics (A.M.H., D.R.), University of Tübingen, Germany; Department of Psychiatry and Psychotherapy (M.B., C.D., O.R., T.H.), Comprehensive Center for Clinical Neurosciences and Mental Health (C3NMH), Medical University of Vienna, Austria; and Center for Rare Diseases (C.D., O.R., T.H.), University of Tübingen, Germany
| | - Claudia Dufke
- From the Research Division Translational Genomics of Neurodegenerative Diseases (A.T., M. Synofzik), Hertie-Institute for Clinical Brain Research and Center of Neurology, and German Center for Neurodegenerative Diseases (DZNE) (A.T., M. Synofzik), University of Tübingen; Department of Neurology and German Center for Vertigo and Balance Disorders (F.H., A.Z., M. Strupp), University Hospital, Ludwig-Maximilians University, Munich, Germany; Department of Biochemistry (M.B.), Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan; Institute of Medical Genetics and Applied Genomics (A.M.H., D.R.), University of Tübingen, Germany; Department of Psychiatry and Psychotherapy (M.B., C.D., O.R., T.H.), Comprehensive Center for Clinical Neurosciences and Mental Health (C3NMH), Medical University of Vienna, Austria; and Center for Rare Diseases (C.D., O.R., T.H.), University of Tübingen, Germany
| | - Olaf Riess
- From the Research Division Translational Genomics of Neurodegenerative Diseases (A.T., M. Synofzik), Hertie-Institute for Clinical Brain Research and Center of Neurology, and German Center for Neurodegenerative Diseases (DZNE) (A.T., M. Synofzik), University of Tübingen; Department of Neurology and German Center for Vertigo and Balance Disorders (F.H., A.Z., M. Strupp), University Hospital, Ludwig-Maximilians University, Munich, Germany; Department of Biochemistry (M.B.), Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan; Institute of Medical Genetics and Applied Genomics (A.M.H., D.R.), University of Tübingen, Germany; Department of Psychiatry and Psychotherapy (M.B., C.D., O.R., T.H.), Comprehensive Center for Clinical Neurosciences and Mental Health (C3NMH), Medical University of Vienna, Austria; and Center for Rare Diseases (C.D., O.R., T.H.), University of Tübingen, Germany
| | - Andreas Zwergal
- From the Research Division Translational Genomics of Neurodegenerative Diseases (A.T., M. Synofzik), Hertie-Institute for Clinical Brain Research and Center of Neurology, and German Center for Neurodegenerative Diseases (DZNE) (A.T., M. Synofzik), University of Tübingen; Department of Neurology and German Center for Vertigo and Balance Disorders (F.H., A.Z., M. Strupp), University Hospital, Ludwig-Maximilians University, Munich, Germany; Department of Biochemistry (M.B.), Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan; Institute of Medical Genetics and Applied Genomics (A.M.H., D.R.), University of Tübingen, Germany; Department of Psychiatry and Psychotherapy (M.B., C.D., O.R., T.H.), Comprehensive Center for Clinical Neurosciences and Mental Health (C3NMH), Medical University of Vienna, Austria; and Center for Rare Diseases (C.D., O.R., T.H.), University of Tübingen, Germany
| | - Dan Rujescu
- From the Research Division Translational Genomics of Neurodegenerative Diseases (A.T., M. Synofzik), Hertie-Institute for Clinical Brain Research and Center of Neurology, and German Center for Neurodegenerative Diseases (DZNE) (A.T., M. Synofzik), University of Tübingen; Department of Neurology and German Center for Vertigo and Balance Disorders (F.H., A.Z., M. Strupp), University Hospital, Ludwig-Maximilians University, Munich, Germany; Department of Biochemistry (M.B.), Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan; Institute of Medical Genetics and Applied Genomics (A.M.H., D.R.), University of Tübingen, Germany; Department of Psychiatry and Psychotherapy (M.B., C.D., O.R., T.H.), Comprehensive Center for Clinical Neurosciences and Mental Health (C3NMH), Medical University of Vienna, Austria; and Center for Rare Diseases (C.D., O.R., T.H.), University of Tübingen, Germany
| | - Tobias Haack
- From the Research Division Translational Genomics of Neurodegenerative Diseases (A.T., M. Synofzik), Hertie-Institute for Clinical Brain Research and Center of Neurology, and German Center for Neurodegenerative Diseases (DZNE) (A.T., M. Synofzik), University of Tübingen; Department of Neurology and German Center for Vertigo and Balance Disorders (F.H., A.Z., M. Strupp), University Hospital, Ludwig-Maximilians University, Munich, Germany; Department of Biochemistry (M.B.), Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan; Institute of Medical Genetics and Applied Genomics (A.M.H., D.R.), University of Tübingen, Germany; Department of Psychiatry and Psychotherapy (M.B., C.D., O.R., T.H.), Comprehensive Center for Clinical Neurosciences and Mental Health (C3NMH), Medical University of Vienna, Austria; and Center for Rare Diseases (C.D., O.R., T.H.), University of Tübingen, Germany
| | - Matthis Synofzik
- From the Research Division Translational Genomics of Neurodegenerative Diseases (A.T., M. Synofzik), Hertie-Institute for Clinical Brain Research and Center of Neurology, and German Center for Neurodegenerative Diseases (DZNE) (A.T., M. Synofzik), University of Tübingen; Department of Neurology and German Center for Vertigo and Balance Disorders (F.H., A.Z., M. Strupp), University Hospital, Ludwig-Maximilians University, Munich, Germany; Department of Biochemistry (M.B.), Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan; Institute of Medical Genetics and Applied Genomics (A.M.H., D.R.), University of Tübingen, Germany; Department of Psychiatry and Psychotherapy (M.B., C.D., O.R., T.H.), Comprehensive Center for Clinical Neurosciences and Mental Health (C3NMH), Medical University of Vienna, Austria; and Center for Rare Diseases (C.D., O.R., T.H.), University of Tübingen, Germany
| | - Michael Strupp
- From the Research Division Translational Genomics of Neurodegenerative Diseases (A.T., M. Synofzik), Hertie-Institute for Clinical Brain Research and Center of Neurology, and German Center for Neurodegenerative Diseases (DZNE) (A.T., M. Synofzik), University of Tübingen; Department of Neurology and German Center for Vertigo and Balance Disorders (F.H., A.Z., M. Strupp), University Hospital, Ludwig-Maximilians University, Munich, Germany; Department of Biochemistry (M.B.), Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan; Institute of Medical Genetics and Applied Genomics (A.M.H., D.R.), University of Tübingen, Germany; Department of Psychiatry and Psychotherapy (M.B., C.D., O.R., T.H.), Comprehensive Center for Clinical Neurosciences and Mental Health (C3NMH), Medical University of Vienna, Austria; and Center for Rare Diseases (C.D., O.R., T.H.), University of Tübingen, Germany.
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10
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Taylor RL, Antunovich T, Chang TMH, Rodrigues M, Baker A, Bergin P, McGuinness B, Roxburgh RH. Hyperactive vestibular and visually enhanced vestibulo-ocular reflexes in autosomal recessive cerebellar ataxia type 3: a case report. J Neurol 2023; 270:1154-1158. [PMID: 36271925 DOI: 10.1007/s00415-022-11422-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 09/29/2022] [Accepted: 09/30/2022] [Indexed: 02/03/2023]
Affiliation(s)
- Rachael L Taylor
- Centre for Brain Research, Neurogenetics Clinic, University of Auckland, Auckland, New Zealand.,Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Tonci Antunovich
- Centre for Brain Research, Neurogenetics Clinic, University of Auckland, Auckland, New Zealand
| | - Thomas Ming Hong Chang
- Centre for Brain Research, Neurogenetics Clinic, University of Auckland, Auckland, New Zealand
| | - Miriam Rodrigues
- Centre for Brain Research, Neurogenetics Clinic, University of Auckland, Auckland, New Zealand.,Neurology Department, Auckland City Hospital, Auckland, New Zealand
| | - Ashleigh Baker
- Centre for Brain Research, Neurogenetics Clinic, University of Auckland, Auckland, New Zealand
| | - Peter Bergin
- Neurology Department, Auckland City Hospital, Auckland, New Zealand
| | - Ben McGuinness
- Radiology Department, Auckland City Hospital, Auckland, New Zealand
| | - Richard H Roxburgh
- Centre for Brain Research, Neurogenetics Clinic, University of Auckland, Auckland, New Zealand. .,Neurology Department, Auckland City Hospital, Auckland, New Zealand.
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11
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Roberts LJ, McVeigh M, Seiderer L, Harding IH, Corben LA, Delatycki M, Szmulewicz DJ. Overview of the Clinical Approach to Individuals With Cerebellar Ataxia and Neuropathy. Neurol Genet 2022; 8:e200021. [PMID: 36187726 PMCID: PMC9520343 DOI: 10.1212/nxg.0000000000200021] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 07/06/2022] [Indexed: 06/16/2023]
Abstract
Increasingly, cerebellar syndromes are recognized as affecting multiple systems. Extracerebellar features include peripheral neuropathies affecting proprioception; cranial neuropathies such as auditory and vestibular; and neuronopathies, for example, dorsal root and vestibular. The presence of such features, which in and of themselves may cause ataxia, likely contribute to key disabilities such as gait instability and falls. Based on the evolving available literature and experience, we outline a clinical approach to the diagnosis of adult-onset ataxia where a combination of cerebellar and peripheral or cranial nerve pathology exists. Objective diagnostic modalities including electrophysiology, oculomotor, and vestibular function testing are invaluable in accurately defining an individual's phenotype. Advances in MRI techniques have led to an increased recognition of disease-specific patterns of cerebellar pathology, including those conditions where neuronopathies may be involved. Depending on availability, a stepwise approach to genetic testing is suggested. This is guided by factors such as pattern of inheritance and age at disease onset, and genetic testing may range from specific genetic panels through to whole-exome and whole-genome sequencing. Management is best performed with the involvement of a multidisciplinary team, aiming at minimization of complications such as falls and aspiration pneumonia and maximizing functional status.
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12
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Borsche M, Tadic V, König IR, Lohmann K, Helmchen C, Brüggemann N. Head impulse testing in bilateral vestibulopathy in patients with genetically defined CANVAS. Brain Behav 2022; 12:e32546. [PMID: 35502508 PMCID: PMC9226818 DOI: 10.1002/brb3.2546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2021] [Revised: 01/09/2022] [Accepted: 02/12/2022] [Indexed: 12/04/2022] Open
Abstract
BACKGROUND To investigate the association between disease duration and the severity of bilateral vestibulopathy in individuals with complete or incomplete CANVAS (Cerebellar Ataxia with Neuropathy and Vestibular Areflexia Syndrome) and biallelic RFC1 repeat expansions. METHODS Retrospective analysis of clinical data and the vestibulo-ocular reflex quantified by the video head impulse test in 20 patients with confirmed biallelic RFC1 repeat expansions. RESULTS Vestibulo-ocular reflex gain at first admittance 6.9 ± 5.0 years after disease onset was 0.16 [0.15-0.31] (median [interquartile range]). Cross-sectional analysis revealed that gain reduction was associated with disease duration. Follow-up measurements were available for ten individuals: eight of them exhibited a progressive decrease of the vestibulo-ocular reflex gain over time. At the first visit, six of all patients (30%) did not show clinical signs of cerebellar ataxia. CONCLUSIONS Our data suggest a pathological horizontal head impulse test, which can easily be obtained in many outpatient clinics, as a sign of bilateral vestibulopathy in genetically confirmed CANVAS that can precede clinically accessible cerebellar ataxia at least in a subset of patients. The presumably continuous decline over time possibly reflects the neurodegenerative character of the disease. Thus, genetic testing for RFC1 mutations in (isolated) bilateral vestibulopathy might allow disease detection before the onset of cerebellar signs. Further studies including a wider spectrum of vestibular function tests are warranted in a prospective design.
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Affiliation(s)
- Max Borsche
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany.,Department of Neurology, University Medical Center Schleswig-Holstein, Campus Lübeck, Lübeck, Germany
| | - Vera Tadic
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany.,Department of Neurology, University Medical Center Schleswig-Holstein, Campus Lübeck, Lübeck, Germany
| | - Inke R König
- Institute of Medical Biometry and Statistics, University of Lübeck, Lübeck, Germany
| | - Katja Lohmann
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
| | - Christoph Helmchen
- Department of Neurology, University Medical Center Schleswig-Holstein, Campus Lübeck, Lübeck, Germany
| | - Norbert Brüggemann
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany.,Department of Neurology, University Medical Center Schleswig-Holstein, Campus Lübeck, Lübeck, Germany
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13
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Abstract
PURPOSE OF REVIEW The current review covers recent advances in bilateral vestibulopathy (BVP) in terms of its etiology, diagnosis, and treatments. RECENT FINDINGS The etiology of BVP depends on its clinical course and associated findings, and genetic abnormalities are increasingly recognized in isolated as well as complicated form of BVP. Recent developments in evaluation of the vestibular function have greatly enhanced the detection of BVP, and introduction of the consensus diagnostic criteria by Barany Society has facilitated research on BVP. Vestibular prosthesis may improve vestibular function, posture, gait and quality of life in patients with BVP and would expand the therapeutic options for BVP in near future. SUMMARY Genetics is expanding its role in identifying the causes of BVP of hitherto unknown etiology. The detection and investigation of BVP have been greatly enhanced by introduction of consensus diagnostic criteria and recent developments in methodology evaluating the vestibular function. Vestibular prothesis appears promising in managing BVP. VIDEO ABSTRACT http://links.lww.com/CONR/A59.
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Affiliation(s)
- Ji-Soo Kim
- Department of Neurology, Seoul National University College of Medicine, Seoul
- Dizziness Center, Clinical Neuroscience Center, and Department of Neurology, Seoul National University Bundang Hospital, Seongnam
| | - Hyo-Jung Kim
- Research Administration Team, Seoul National University Bundang Hospital, Seongnam, South Korea
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14
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Halmágyi GM, Szmulewicz DJ. Vestibular function testing in patients with RFC1 mutations. J Neurol 2021; 268:4894-4896. [PMID: 34258633 DOI: 10.1007/s00415-021-10698-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Revised: 07/02/2021] [Accepted: 07/02/2021] [Indexed: 11/30/2022]
Affiliation(s)
- Gábor M Halmágyi
- Neurology Department, Royal Prince Alfred Hospital, Camperdown, Sydney, NSW, 2088, Australia.
| | - David J Szmulewicz
- Balance Disorders and Ataxia Service, Royal Victoria Eye and Ear Hospital, East Melbourne, Melbourne, VIC, 3002, Australia
- The Florey Institute of Neuroscience and Mental Health, Parkville, Melbourne, VIC, 3052, Australia
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15
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Matos PCAAP, Rezende TJR, Schmitt GS, Bonadia LC, Reis F, Martinez ARM, de Lima FD, Bueno MGDA, Tomaselli PJ, Cendes F, Pedroso JL, Barsottini OGP, Marques W, França M. Brain Structural Signature of RFC1-Related Disorder. Mov Disord 2021; 36:2634-2641. [PMID: 34241918 DOI: 10.1002/mds.28711] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 06/01/2021] [Accepted: 06/16/2021] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND The cerebellar ataxia, neuropathy, and vestibular areflexia syndrome was initially described in the early 1990s as a late-onset slowly progressive condition. Its underlying genetic cause was recently mapped to the RFC1 gene, and additional reports have expanded on the phenotypic manifestations related to RFC1, although little is known about the pattern and extent of structural brain abnormalities in this condition. OBJECTIVE The aim is to characterize the structural signature of brain damage in RFC1-related disorder, correlating the findings with clinical symptoms and normal brain RFC1 expression. METHODS We recruited 22 individuals with molecular confirmation of RFC1 expansions and submitted them to high-resolution 3T magnetic resonance imaging scans. We performed multimodal analyses to assess separately cerebral and cerebellar abnormalities within gray and white matter (WM). The results were compared with a group of 22 age- and sex-matched controls. RESULTS The mean age and disease duration of patients were 62.8 and 10.9 years, respectively. Ataxia, sensory neuronopathy, and vestibular areflexia were the most frequent manifestations, but parkinsonism and pyramidal signs were also noticed. We found that RFC1-related disorder is characterized by widespread and relatively symmetric cerebellar and basal ganglia atrophy. There is brainstem volumetric reduction along all its segments. Cerebral WM is also involved-mostly the corpus callosum and deep tracts, but cerebral cortical damage is rather restricted. CONCLUSION This study adds new relevant insights into the pathophysiological mechanisms of RFC1-related disorder. It should no longer be considered a purely cerebellar and sensory pathway disorder. Basal ganglia and deep cerebral WM are additional targets of damage. © 2021 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Paula Camila A A P Matos
- Division of General Neurology and Ataxia Unit, Department of Neurology, Federal University of São Paulo (UNIFESP), São Paulo, Brazil
| | - Thiago J R Rezende
- Department of Neurology, School of Medical Sciences, University of Campinas (UNICAMP), Campinas, Brazil
| | - Gabriel S Schmitt
- Department of Neurology, School of Medical Sciences, University of Campinas (UNICAMP), Campinas, Brazil
| | - Luciana Cardoso Bonadia
- Department of Medical Genetics, School of Medical Sciences, University of Campinas (UNICAMP), Campinas, Brazil
| | - Fabiano Reis
- Department of Radiology, School of Medical Sciences, University of Campinas (UNICAMP), Campinas, Brazil
| | - Alberto R M Martinez
- Department of Neurology, School of Medical Sciences, University of Campinas (UNICAMP), Campinas, Brazil
| | - Fabrício D de Lima
- Department of Neurology, School of Medical Sciences, University of Campinas (UNICAMP), Campinas, Brazil
| | | | - Pedro José Tomaselli
- Department of Neuroscience and Behavioural Science, School of Medicine, University of São Paulo (USP) of Ribeirão Preto, Ribeirão Preto, Brazil
| | - Fernando Cendes
- Department of Neurology, School of Medical Sciences, University of Campinas (UNICAMP), Campinas, Brazil
| | - José Luiz Pedroso
- Division of General Neurology and Ataxia Unit, Department of Neurology, Federal University of São Paulo (UNIFESP), São Paulo, Brazil
| | - Orlando G P Barsottini
- Division of General Neurology and Ataxia Unit, Department of Neurology, Federal University of São Paulo (UNIFESP), São Paulo, Brazil
| | - Wilson Marques
- Department of Neuroscience and Behavioural Science, School of Medicine, University of São Paulo (USP) of Ribeirão Preto, Ribeirão Preto, Brazil
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