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Ekenstedt KJ, Minor KM, Shelton GD, Hammond JJ, Miller AD, Taylor SM, Huang Y, Mickelson JR. A SACS deletion variant in Great Pyrenees dogs causes autosomal recessive neuronal degeneration. Hum Genet 2023; 142:1587-1601. [PMID: 37758910 PMCID: PMC10602964 DOI: 10.1007/s00439-023-02599-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Accepted: 09/04/2023] [Indexed: 09/29/2023]
Abstract
ARSACS (autosomal recessive spastic ataxia of Charlevoix-Saguenay) is a human neurological disorder characterized by progressive cerebellar ataxia and peripheral neuropathy. A recently recognized disorder in Great Pyrenees dogs is similarly characterized by widespread central nervous system degeneration leading to progressive cerebellar ataxia and spasticity, combined with peripheral neuropathy. Onset of clinical signs occurred in puppies as young as 4 months of age, with slow progression over several years. A multi-generation pedigree suggested an autosomal recessive mode of inheritance. Histopathology revealed consistent cerebellar Purkinje cell degeneration, neuronal degeneration in brainstem nuclei, widespread spinal cord white matter degeneration, ganglion cell degeneration, inappropriately thin myelin sheaths or fully demyelinated peripheral nerve fibers, and normal or only mild patterns of denervation atrophy in skeletal muscles. Genome-wide single nucleotide polymorphism (SNP) genotype data was collected from 6 cases and 26 controls, where homozygosity mapping identified a 3.3 Mb region on CFA25 in which all cases were homozygous and all controls were either heterozygous or homozygous for alternate haplotypes. This region tagged the SACS gene where variants are known to cause ARSACS. Sanger sequencing of SACS in affected dogs identified a 4 bp deletion that causes a frame shift and truncates 343 amino acids from the C terminus of the encoded sacsin protein (p.Val4244AlafsTer32). Our clinical and histopathological descriptions of this canine disorder contribute to the description of human ARSACS and represents the first naturally occurring large animal model of this disorder.
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Affiliation(s)
- Kari J Ekenstedt
- Department of Basic Medical Sciences, College of Veterinary Medicine, Purdue University, Lynn Hall, 625 Harrison Street, West Lafayette, IN, 47907, USA.
| | - Katie M Minor
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, Saint Paul, MN, 55108, USA
| | - G Diane Shelton
- Department of Pathology, School of Medicine, University of California San Diego, La Jolla, CA, 92093, USA
| | - James J Hammond
- Department of Neurology, Pieper Memorial Veterinary Center, Middletown, CT, 06457, USA
| | - Andrew D Miller
- Section of Anatomic Pathology, Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, 14853, USA
| | - Susan M Taylor
- Department of Small Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, S7N 5B4, Canada
| | - Yanyun Huang
- Prairie Diagnostic Services, Inc., Saskatoon, SK, S7N 5B4, Canada
| | - James R Mickelson
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, Saint Paul, MN, 55108, USA
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2
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Hepschke JL, Rajabally YA, Mollan SP. Diagnostic Optic Nerve Features in Autosomal Recessive Spastic Ataxia of Charlevoix-Saguenay. JAMA Neurol 2023; 80:104-106. [PMID: 36374509 DOI: 10.1001/jamaneurol.2022.3961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This case report describes the optic nerve features of a male patient aged 23 years with a diagnosis of autosomal recessive spastic ataxia of Charlevoix-Saguenay.
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Affiliation(s)
- Jenny L Hepschke
- Birmingham Neuro-Ophthalmology, University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom
| | - Yusuf Ali Rajabally
- Department of Neurology, University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom
| | - Susan P Mollan
- Birmingham Neuro-Ophthalmology, University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom.,Department of Neurology, University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom
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3
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Bae JH, Jeong HB, Kim HR, Song KS, Park ST, Ahn SW. A Case of HSP Carrying c.1537-11A > G Mutation of the SPAST Gene Presented as Stiff-Person Syndrome. Neurol India 2021; 69:1053-1054. [PMID: 34507445 DOI: 10.4103/0028-3886.325344] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- Jae-Han Bae
- Department of Neurology, Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Republic of Korea
| | - Hae-Bong Jeong
- Department of Neurology, Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Republic of Korea
| | - Hye Ryoun Kim
- Department of Laboratory Medicine, Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Republic of Korea
| | - Kwang-Sup Song
- Department of Orthopedic Surgery, Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Republic of Korea
| | - Sung-Taek Park
- Department of Obstetrics and Gynecology, Hallym University Kangnam Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Republic of Korea
| | - Suk-Won Ahn
- Department of Neurology, Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Republic of Korea
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Sahin I, Saat H. Hereditary spastic paraplegia: new insights into clinical variability and spasticity-ataxia phenotype, and novel mutations. Acta Neurol Belg 2021; 122:1529-1535. [PMID: 34420199 DOI: 10.1007/s13760-021-01779-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 08/16/2021] [Indexed: 12/30/2022]
Abstract
INTRODUCTION Hereditary spastic paraplegias (HSPs), a genetically heterogeneous group of neurodegenerative diseases, have an incidence of around 3 to 9 individuals every 100,000. Due to the broad clinical and genetic variability of HSPs, it is challenging to diagnose the disorder quickly and precisely. Hereditary spastic ataxias (HSAs) and HSPs are overlapping diseases, and their intersection has been gradually identified by next-generation sequencing. The idea of the spasticity-ataxia phenotype (SAP) spectrum is further substantiated by the similarities in phenotypes and underlying genes in ataxias and inherited spastic paraplegias and the related cellular processes and disease mechanisms these disorders exhibit. METHODS Whole-exome sequencing was performed on the 25 spastic or spastic-ataxic gait patients. RESULTS Twenty-two specific HSPs-HSAs-SAP mutations, including 14 novel mutations, were found in 25 cases from 18 Turkish and 2 Syrian families. This research discovers many novel hereditary spastic paraplegia (HSP) mutations and shows a robust genotype-phenotype heterogeneity in the disease. CONCLUSIONS This research helped expand the clinical and molecular scope of HSP and clarified the concept of the spasticity-ataxia phenotype, further enhancing our understanding of the complicated form of HSP and its association with ataxia. Our data broadens the spectrum of HSPs and HSAs related gene mutations and provides insights for genotype-phenotype correlations for HSPs and HSAs.
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Akçimen F, Ross JP, Bourassa CV, Liao C, Rochefort D, Gama MTD, Dicaire MJ, Barsottini OG, Brais B, Pedroso JL, Dion PA, Rouleau GA. Investigation of the RFC1 Repeat Expansion in a Canadian and a Brazilian Ataxia Cohort: Identification of Novel Conformations. Front Genet 2019; 10:1219. [PMID: 31824583 PMCID: PMC6884024 DOI: 10.3389/fgene.2019.01219] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Accepted: 11/04/2019] [Indexed: 12/30/2022] Open
Abstract
A biallelic pentanucleotide expansion in the RFC1 gene has been reported to be a common cause of late-onset ataxia. In the general population, four different repeat conformations are observed: wild type sequence AAAAG (11 repeats) and longer expansions of either AAAAG, AAAGG or AAGGG sequences. However only the biallelic AAGGG expansions were reported to cause late-onset ataxia. In this study, we aimed to assess the prevalence and nature of RFC1 repeat expansions in three cohorts of adult-onset ataxia cases: Brazilian (n = 23) and Canadian (n = 26) cases that are negative for the presence of variants in other known ataxia-associated genes, as well as a cohort of randomly selected Canadian cases (n = 128) without regard to a genetic diagnosis. We identified the biallelic AAGGG expansion in only one Brazilian family which presented two affected siblings, and in one Canadian case. We also observed two new repeat conformations, AAGAG and AGAGG, which suggests the pentanucleotide expansion sequence has a dynamic nature. To assess the frequency of these new repeat conformations in the general population, we screened 163 healthy individuals and observed the AAGAG expansion to be more frequent in cases than in control individuals. While additional studies will be necessary to asses the pathogenic impact of biallelic genotypes that include the novel expanded conformations, their occurrence should nonetheless be examined in future studies.
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Affiliation(s)
- Fulya Akçimen
- Department of Human Genetics, McGill University, Montréal, QC, Canada
- Montreal Neurological Institute and Hospital, McGill University, Montréal, QC, Canada
| | - Jay P. Ross
- Department of Human Genetics, McGill University, Montréal, QC, Canada
- Montreal Neurological Institute and Hospital, McGill University, Montréal, QC, Canada
| | - Cynthia V. Bourassa
- Montreal Neurological Institute and Hospital, McGill University, Montréal, QC, Canada
| | - Calwing Liao
- Department of Human Genetics, McGill University, Montréal, QC, Canada
- Montreal Neurological Institute and Hospital, McGill University, Montréal, QC, Canada
| | - Daniel Rochefort
- Montreal Neurological Institute and Hospital, McGill University, Montréal, QC, Canada
| | - Maria Thereza Drumond Gama
- Division of General Neurology and Ataxia Unit, Department of Neurology, Federal University of São Paulo (UNIFESP), São Paulo, Brazil
| | - Marie-Josée Dicaire
- Montreal Neurological Institute and Hospital, McGill University, Montréal, QC, Canada
| | - Orlando G. Barsottini
- Division of General Neurology and Ataxia Unit, Department of Neurology, Federal University of São Paulo (UNIFESP), São Paulo, Brazil
| | - Bernard Brais
- Department of Human Genetics, McGill University, Montréal, QC, Canada
- Montreal Neurological Institute and Hospital, McGill University, Montréal, QC, Canada
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada
| | - José Luiz Pedroso
- Division of General Neurology and Ataxia Unit, Department of Neurology, Federal University of São Paulo (UNIFESP), São Paulo, Brazil
| | - Patrick A. Dion
- Montreal Neurological Institute and Hospital, McGill University, Montréal, QC, Canada
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada
| | - Guy A. Rouleau
- Department of Human Genetics, McGill University, Montréal, QC, Canada
- Montreal Neurological Institute and Hospital, McGill University, Montréal, QC, Canada
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada
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Artero Castro A, Machuca C, Rodriguez Jimenez FJ, Jendelova P, Erceg S. Short Review: Investigating ARSACS: models for understanding cerebellar degeneration. Neuropathol Appl Neurobiol 2019; 45:531-537. [PMID: 30636067 DOI: 10.1111/nan.12540] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 12/19/2018] [Indexed: 11/29/2022]
Abstract
Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is an early-onset neurodegenerative disease that includes progressive cerebellar dysfunction. ARSACS is caused by an autosomal recessive loss-of-function mutation in the SACS gene, which encodes for SACSIN. Although animal models are still necessary to investigate the role of SACSIN in the pathology of this disease, more reliable human cellular models need to be generated to better understand the cerebellar pathophysiology of ARSACS. The discovery of human induced pluripotent stem cells (hiPSC) has permitted the derivation of patient-specific cells. These cells have an unlimited self-renewing capacity and the ability to differentiate into different neural cell types, allowing studies of disease mechanism, drug discovery and cell replacement therapies. In this study, we discuss how the hiPSC-derived cerebellar organoid culture offers novel strategies for targeting the pathogenic mutations related to ARSACS. We also highlight the advantages and challenges of this 3D cellular model, as well as the questions that still remain unanswered.
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Affiliation(s)
- A Artero Castro
- Stem Cells Therapies in Neurodegenerative Diseases Lab, Research Center "Principe Felipe", Valencia, Spain
| | - C Machuca
- Stem Cells Therapies in Neurodegenerative Diseases Lab, Research Center "Principe Felipe", Valencia, Spain.,Unit of Genetics and Genomics of Neuromuscular and Neurodegenerative Disorders and Service of Genomics and Translational Genetics, Research Center "Principe Felipe", Valencia, Spain
| | - F J Rodriguez Jimenez
- Stem Cells Therapies in Neurodegenerative Diseases Lab, Research Center "Principe Felipe", Valencia, Spain
| | - P Jendelova
- Institute of Experimental Medicine, Department of Neuroscience, Academy of Science of the Czech Republic, Prague, Czech Republic
| | - S Erceg
- Stem Cells Therapies in Neurodegenerative Diseases Lab, Research Center "Principe Felipe", Valencia, Spain.,National Stem Cell Bank-Valencia Node, Platform for Proteomics, Genotyping and Cell Lines, PRB3, ISCIII, Research Center "Principe Felipe", Valencia, Spain
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7
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Dougherty SC, Harper A, Al Saif H, Vorona G, Haines SR. A Chromosomal Deletion and New Frameshift Mutation Cause ARSACS in an African-American. Front Neurol 2018; 9:956. [PMID: 30498468 PMCID: PMC6249318 DOI: 10.3389/fneur.2018.00956] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 10/25/2018] [Indexed: 01/18/2023] Open
Abstract
Autosomal Recessive Spastic Ataxia of Charlevoix-Saguenay (ARSACS) is a rare, progressive, neurodegenerative disease characterized by ataxia, spasticity and polyneuropathy. First described in the French-Canadian population of Quebec in 1978, ARSACS has since been identified in multiple patients worldwide. In this clinical case report, we describe the evaluation of an 11-years-old African-American male who presented to neuromuscular clinic for assessment of a gait abnormality. He had a history of gross motor delay since early childhood, frequent falls and a below average IQ. Chromosomal microarray revealed a 1.422 megabase loss in the 13q12.12 region, which includes the SACS gene. Next Generation Sequencing then showed a novel, predicted to be pathogenic missense mutation (c.11824dup) of this gene. His clinical presentation and neurological imaging further confirmed the diagnosis of ARSACS. To our knowledge, this is the first reported case of this disease in the African-American population of the United States. This case report further highlights the growing trend of identifying genetic diseases previously restricted to single, ethnically isolated regions in many different ethnic groups worldwide.
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Affiliation(s)
- Sean C Dougherty
- Department of Neurology, Virginia Commonwealth University, Richmond, VA, United States
| | - Amy Harper
- Department of Neurology, Virginia Commonwealth University, Richmond, VA, United States
| | - Hind Al Saif
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, VA, United States
| | - Gregory Vorona
- Department of Radiology, Virginia Commonwealth University, Richmond, VA, United States
| | - Scott R Haines
- Department of Neurology, Virginia Commonwealth University, Richmond, VA, United States
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8
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Borruat FX, Holder GE, Bremner F. Inner Retinal Dysfunction in the Autosomal Recessive Spastic Ataxia of Charlevoix-Saguenay. Front Neurol 2017; 8:523. [PMID: 29075231 PMCID: PMC5643501 DOI: 10.3389/fneur.2017.00523] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 09/20/2017] [Indexed: 11/25/2022] Open
Abstract
The autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is associated with structural retinal abnormalities either directly visible on funduscopy or revealed by optical coherence tomography (OCT). Most patients with ARSACS have a whitish peripapillary appearance corresponding to a thickening of the peripapillary retinal nerve fiber layer. OCT has also shown an absence of the physiological foveal depression. Abnormal electroretinography (ERG) has previously been reported in only two cases, without further details. This report describes a patient with ARSACS in whom careful full-field ERG revealed dysfunction of the retinal On− bipolar cells with sparing of photoreceptor function. This is the first report of inner retinal dysfunction in ARSACS.
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Affiliation(s)
| | - Graham E Holder
- Moorfields Eye Hospital, London, United Kingdom.,University College London Institute of Ophthalmology, London, United Kingdom
| | - Fion Bremner
- The National Hospital for Neurology and Neurosurgery, London, United Kingdom
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9
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Tanaka F, Doi H, Kunii M. Autosomal recessive spinocerebellar ataxias in Japan. Rinsho Shinkeigaku 2016; 56:395-9. [PMID: 27181749 DOI: 10.5692/clinicalneurol.cn-000879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Recent new sequencing techniques allow the identification of novel responsible genes for autosomal recessive spinocerebellar ataxias (ARCAs). However, the same phenotypes are sometimes attributed to the different responsible genes in ARCAs. On the contrary, the same responsible genes may cause heterogeneous phenotypes with respect to the age at onset, symptoms, and the severity of the disease progression. In addition, it is an important issue to clarify whether the gene mutations identified in Caucasian patients with infantile-onset ARCAs are also observed in Japanese patients with adult-onset ARCAs. In this article we review the characteristics of several ARCAs, the existence of which has been recently identified or confirmed in Japan.
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Affiliation(s)
- Fumiaki Tanaka
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine
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10
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Subramony S, Moscovich M, Ashizawa T. Genetics and Clinical Features of Inherited Ataxias. Mov Disord 2015. [DOI: 10.1016/b978-0-12-405195-9.00062-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Abstract
Background:Genetic and environmental factors are important determinants of disease distribution. Several disorders associated with ataxia are known to occur more commonly in certain ethnic groups; for example, the disequilibrium syndrome in the Hutterites. The aim of this study was to determine the ethnic and geographic distribution of pediatric patients with chronic ataxia in Manitoba, Canada.Methods:We identified 184 patients less than 17 years-of-age with chronic ataxia during 1991-2008 from multiple sources. Their diagnosis, ethnicity and place of residence were determined following a chart review.Results:Most patients resided in Manitoba (N=177) and the majority in Winnipeg, the provincial capital. Thirty five Aboriginal, 29 Mennonite and 11 Hutterite patients resided in Manitoba. The latter two groups were significantly overrepresented in our cohort. Ataxia telangiectasia, mitochondrial disorders, and non-progressive ataxia of unknown etiology associated with pyramidal tracts signs and developmental delay were significantly more common in Mennonite patients. Four of five patients with neuronal migration disorders associated with chronic ataxia were Aboriginal. Few isolated disorders with chronic ataxia occurred in the 11 Hutterite patients including a Joubert syndrome related disorder.Conclusions:Three disorders associated with chronic ataxia were more prevalent than expected in Mennonites in Manitoba. Few rare disorders were more prevalent in the Hutterite and Aboriginal population. Further research is needed to determine the risk factors underlying these variations in prevalence within different ethnic groups. The unique risk factor profiles of each ethnic group need to be considered in health promotion endeavors.
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Abstract
Abstract:Background:The growing number of spastic ataxia of Charlevoix-Saguenay (SACS) gene mutations reported worldwide has broadened the clinical phenotype of autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS). The identification of Quebec ARSACS cases without two knownSACSmutation led to the development of a multi-modal genomic strategy to uncover mutations in this large gene and explore phenotype variability.Methods:Search forSACSmutations by combining various methods on 20 cases with a classical French-Canadian ARSACS phenotype without two mutations and a group of 104 sporadic or recessive spastic ataxia cases of unknown cause. Western blot on lymphoblast protein from cases with different genotypes was probed to establish if they still expressed sacsin.Results:A total of 12 mutations, including 7 novels, were uncovered in Quebec ARSACS cases. The screening of 104 spastic ataxia cases of unknown cause for 98SACSmutations did not uncover carriers of two mutations. Compounds heterozygotes for one missenseSACSmutation were found to minimally express sacsin.Conclusions:The large number ofSACSmutations present even in Quebec suggests that the size of the gene alone may explain the great genotypic diversity. This study does not support an expanding ARSACS phenotype in the French-Canadian population. Most mutations lead to loss of function, though phenotypic variability in other populations may reflect partial loss of function with preservation of some sacsin expression. Our results also highlight the challenge ofSACSmutation screening and the necessity to develop new generation sequencing methods to ensure low cost complete gene sequencing.
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A recurrent mutation inDEPDC5predisposes to focal epilepsies in the French-Canadian population. Clin Genet 2013; 86:570-4. [DOI: 10.1111/cge.12311] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Revised: 10/17/2013] [Accepted: 10/30/2013] [Indexed: 11/26/2022]
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Garcia-Martin E, Bambo MP, Gazulla J, Larrosa JM, Polo V, Fuertes MI, Fuentes JL, Ferreras A, Pablo LE. [Finding of retinal nerve fiber layer hypertrophy in ataxia of Charlevoix-Saguenay patients]. ACTA ACUST UNITED AC 2013; 89:207-11. [PMID: 24269465 DOI: 10.1016/j.oftal.2012.11.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Revised: 10/31/2012] [Accepted: 11/19/2012] [Indexed: 11/26/2022]
Abstract
PURPOSE/METHODS To present the neuro-ophthalmology examination in 5 spastic ataxia of Charlevoix-Saguenay (ARSACS) patients showing significant increases in retinal nerve fiber layer (RNFL) thickness. RESULTS/CONCLUSIONS All patients showed abnormal visual fields, normal optic discs with increased visibility of RNFL in color stereo-photographs, normal examination with Heidelberg Retina Tomography instrument, and moderate to markedly increased RNFL thickness in Cirrus Optical Coherence Tomography evaluation (average thickness: 119 to 220 microns). We found evidence that RNFL hypertrophy may be an alternative funduscopic finding to the hypermyelinated retinal fibers in previous reports. A revision of ARSACS diagnostic criteria, particularly with regard to retinal alterations, is necessary.
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Affiliation(s)
- E Garcia-Martin
- Servicio de Oftalmología, Hospital Universitario Miguel Servet, Zaragoza, España; Instituto Aragonés de Ciencias de la Salud (IACS), Zaragoza, España.
| | - M P Bambo
- Servicio de Oftalmología, Hospital Universitario Miguel Servet, Zaragoza, España; Instituto Aragonés de Ciencias de la Salud (IACS), Zaragoza, España
| | - J Gazulla
- Servicio de Neurología, Hospital Universitario Miguel Servet, Zaragoza, España
| | - J M Larrosa
- Servicio de Oftalmología, Hospital Universitario Miguel Servet, Zaragoza, España; Instituto Aragonés de Ciencias de la Salud (IACS), Zaragoza, España
| | - V Polo
- Servicio de Oftalmología, Hospital Universitario Miguel Servet, Zaragoza, España; Instituto Aragonés de Ciencias de la Salud (IACS), Zaragoza, España
| | - M I Fuertes
- Servicio de Oftalmología, Hospital Universitario Miguel Servet, Zaragoza, España; Instituto Aragonés de Ciencias de la Salud (IACS), Zaragoza, España
| | - J L Fuentes
- Servicio de Oftalmología, Hospital Universitario Miguel Servet, Zaragoza, España
| | - A Ferreras
- Servicio de Oftalmología, Hospital Universitario Miguel Servet, Zaragoza, España; Instituto Aragonés de Ciencias de la Salud (IACS), Zaragoza, España
| | - L E Pablo
- Servicio de Oftalmología, Hospital Universitario Miguel Servet, Zaragoza, España; Instituto Aragonés de Ciencias de la Salud (IACS), Zaragoza, España
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Garcia-Martin E, Pablo LE, Gazulla J, Polo V, Ferreras A, Larrosa JM. Retinal nerve fibre layer thickness in ARSACS: myelination or hypertrophy? Br J Ophthalmol 2012; 97:238-41. [PMID: 23077228 PMCID: PMC3582091 DOI: 10.1136/bjophthalmol-2012-302309] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- Elena Garcia-Martin
- Ophthalmology Department, Miguel Servet University Hospital, Zaragoza, Spain
- Research Department, Aragones Institute of Health Sciences, Zaragoza, Spain
| | - Luis E Pablo
- Ophthalmology Department, Miguel Servet University Hospital, Zaragoza, Spain
- Research Department, Aragones Institute of Health Sciences, Zaragoza, Spain
| | - Jose Gazulla
- Neurology Department, Miguel Servet University Hospital, Zaragoza, Spain
| | - Vicente Polo
- Ophthalmology Department, Miguel Servet University Hospital, Zaragoza, Spain
- Research Department, Aragones Institute of Health Sciences, Zaragoza, Spain
| | - Antonio Ferreras
- Ophthalmology Department, Miguel Servet University Hospital, Zaragoza, Spain
- Research Department, Aragones Institute of Health Sciences, Zaragoza, Spain
| | - Jose M Larrosa
- Ophthalmology Department, Miguel Servet University Hospital, Zaragoza, Spain
- Research Department, Aragones Institute of Health Sciences, Zaragoza, Spain
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Mitochondrial dysfunction and Purkinje cell loss in autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS). Proc Natl Acad Sci U S A 2012; 109:1661-6. [PMID: 22307627 DOI: 10.1073/pnas.1113166109] [Citation(s) in RCA: 138] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is a childhood-onset neurological disease resulting from mutations in the SACS gene encoding sacsin, a 4,579-aa protein of unknown function. Originally identified as a founder disease in Québec, ARSACS is now recognized worldwide. Prominent features include pyramidal spasticity and cerebellar ataxia, but the underlying pathology and pathophysiological mechanisms are unknown. We have generated an animal model for ARSACS, sacsin knockout mice, that display age-dependent neurodegeneration of cerebellar Purkinje cells. To explore the pathophysiological basis for this observation, we examined the cell biological properties of sacsin. We show that sacsin localizes to mitochondria in non-neuronal cells and primary neurons and that it interacts with dynamin-related protein 1, which participates in mitochondrial fission. Fibroblasts from ARSACS patients show a hyperfused mitochondrial network, consistent with defects in mitochondrial fission. Sacsin knockdown leads to an overly interconnected and functionally impaired mitochondrial network, and mitochondria accumulate in the soma and proximal dendrites of sacsin knockdown neurons. Disruption of mitochondrial transport into dendrites has been shown to lead to abnormal dendritic morphology, and we observe striking alterations in the organization of dendritic fields in the cerebellum of knockout mice that precedes Purkinje cell death. Our data identifies mitochondrial dysfunction/mislocalization as the likely cellular basis for ARSACS and indicates a role for sacsin in regulation of mitochondrial dynamics.
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Familial Alzheimer Disease in Canada. Can J Neurol Sci 2010; 37:302-3. [DOI: 10.1017/s0317167100010143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Salman MS, Marles SL, Booth FA, Del Bigio MR. Early-onset neurodegenerative disease of the cerebellum and motor axons. Pediatr Neurol 2009; 40:365-70. [PMID: 19380073 DOI: 10.1016/j.pediatrneurol.2008.11.020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2008] [Revised: 11/17/2008] [Accepted: 11/25/2008] [Indexed: 12/11/2022]
Abstract
We describe a novel hereditary neurodegenerative disease of infancy affecting an Aboriginal family from northern Manitoba, Canada. The parents are nonconsanguineous, without a family history of neurodegenerative diseases. Four of 10 siblings (three males and one female) presented with neurologic abnormalities including arthrogryposis, seizures, and severe developmental delay shortly after birth. In two children, cerebellar atrophy and mild cerebral atrophy were documented on neuroimaging. Two children, a boy who died at age 40 months and a girl who died at age 22 months, underwent muscle biopsies at 3 weeks and 4 months of age, respectively. The biopsies revealed fiber-size variability in the boy, and grouped atrophy with fiber-type grouping in the girl. Two boys who died at ages 7.5 and 37 months underwent autopsies that indicated severe atrophy of the cerebellar hemispheres (especially the inferior lobules and vermis), hypomyelination of white-matter fascicles in the striatum, severe atrophy of corticospinal tracts in the brainstem and spinal cord, and atrophy of the anterior spinal roots. In the spinal cord, motor neuron cell bodies and the posterior columns were spared. This clinical entity likely represents a novel neurodegenerative disease of the cerebellum and long motor axons.
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Affiliation(s)
- Michael S Salman
- Department of Pediatrics and Child Health, University of Manitoba, Winnipeg, Manitoba, Canada
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Meijer IA, Dupré N, Brais B, Cossette P, St-Onge J, Rioux MF, Benard M, Rouleau GA. SPG4 founder effect in French Canadians with hereditary spastic paraplegia. Can J Neurol Sci 2007; 34:211-4. [PMID: 17598600 DOI: 10.1017/s0317167100006065] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
BACKGROUND The most common cause of autosomal dominant Hereditary Spastic Paraplegia (HSP) is mutations in the SPG4 gene. We have previously identified novel SPG4 mutations in a collection of North American families including the c.G1801A mutation present in two families from Quebec. The aim of this study is to estimate the frequency of the c.G1801A mutation in the French Canadian (FC) population and to determine whether this mutation originates from a common ancestor. METHODS We collected and sequenced exon 15 in probands of 37 families. Genotypes of markers flanking the SPG4 gene were used to construct haplotypes in five families. Clinical information was reviewed by a neurologist with expertise in HSP. RESULTS We have identified three additional unrelated families with the c.G1801A mutation and haplotype analysis revealed that all five families share a common ancestor. The mutation is present in 7% of all our FC families and explains half of our spastin linked FC families. The phenotype associated with the c.G1801A genotype is pure HSP with bladder involvement. CONCLUSION In this study we have determined that the relative frequency of the c.G1801A mutation in our FC collection is 7%, and approximately 50% in the spastin positive FC group. This mutation is the most common HSP mutation identified in this population to date and is suggestive of a founder effect in Quebec.
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Affiliation(s)
- Inge A Meijer
- Center for the Study of Brain Diseases, CHUM Research Center, Notre-Dame Hospital, Montreal, QC, Canada
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Dupré N, Bouchard JP, Gros-Louis F, Rouleau GA. [Mutations in SYNE-1 lead to a newly discovered form of autosomal recessive cerebellar ataxia]. Med Sci (Paris) 2007; 23:261-2. [PMID: 17349286 DOI: 10.1051/medsci/2007233261] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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