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Abstract
Spinocerebellar ataxias (SCAs) are a clinically heterogeneous group of disorders. Current molecular classification corresponds to the order of gene description (SCA1-SCA 25). The prevalence of SCAs is estimated to be 1-4/100,000. Patients exhibit usually a slowly progressive cerebellar syndrome with various combinations of oculomotor disorders, dysarthria, dysmetria/kinetic tremor, and/or ataxic gait. They can present also with pigmentary retinopathy, extrapyramidal movement disorders (parkinsonism, dyskinesias, dystonia, chorea), pyramidal signs, cortical symptoms (seizures, cognitive impairment/behavioral symptoms), peripheral neuropathy. SCAs are also genetically heterogeneous and the clinical diagnosis of subtypes of SCAs is complicated by the salient overlap of the phenotypes between genetic subtypes. The following clinical features have some specific values for predicting a gene defect: slowing of saccades in SCA2, ophthalmoplegia in SCA1, SCA2 and SCA3, pigmentary retinopathy in SCA7, spasticity in SCA3, dyskinesias associated with a mutation in the fibroblast growth factor 14 (FGF 14) gene, cognitive impairment/behavioral symptoms in SCA17 and DRPLA, seizures in SCA10, SCA17 and DRPLA, peripheral neuropathy in SCA1, SCA2, SCA3, SCA4, SCA8, SCA18 and SCA25. Neurophysiological findings are compatible with a dying-back axonopathy and/or a neuronopathy. Three patterns of atrophy can be identified on brain MRI: a pure cerebellar atrophy, a pattern of olivopontocerebellar atrophy, and a pattern of global brain atrophy. A remarkable observation is the presence of dentate nuclei calcifications in SCA20, resulting in a low signal on brain MRI sequences. Several identified mutations correspond to expansions of repeated trinucleotides (CAG repeats in SCA1, SCA2, SCA3, SCA6, SCA7, SCA17 and DRPLA, CTG repeats in SCA8). A pentanucleotide repeat expansion (ATTCT) is associated with SCA10. Missense mutations have also been found recently. Anticipation is a main feature of SCAs, due to instability of expanded alleles. Anticipation may be particularly prominent in SCA7. It is estimated that extensive genetic testing leads to the identification of the causative gene in about 60-75 % of cases. Our knowledge of the molecular mechanisms of SCAs is rapidly growing, and the development of relevant animal models of SCAs is bringing hope for effective therapies in human.
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52
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Autosomal dominant cerebellar ataxia. NEURODEGENER DIS 2005. [DOI: 10.1017/cbo9780511544873.048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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53
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Abstract
The group of spinocerebellar ataxias (SCAs) includes more than 20 subgroups based only on genetic research. The "ataxia genes" are autosomal; the "disease-alleles" are dominant, and many of them, but not all, encode a protein with an abnormally long polyglutamine domain. In DNA, this domain can be detected as an elongated CAG repeat region, which is the basis of genetic diagnostics. The polyglutamine tails often tend to aggregate and form inclusions. In some cases, protein-protein interactions are the key to understanding the disease. Protein partners of ataxia proteins include phosphatases and components of chromatin and the transcriptional machinery. To date, investigation of spinocerebellar ataxias involves population genetics, molecular methods, and studying model organisms. However, there is still no efficient therapy for patients. Here, we review the genetic and molecular data gained on spinocerebellar ataxias.
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Affiliation(s)
- Viktor Honti
- Department of Neurology, Albert Szent-Györgyi Medical and Pharmaceutical Center, University of Szeged, Szeged, Hungary.
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54
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Fluorescent Multiplex PCR: Fast Method for Autosomal Dominant Spinocerebellar Ataxias Screening. RUSS J GENET+ 2005. [DOI: 10.1007/s11177-005-0144-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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55
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van de Warrenburg BPC, Sinke RJ, Kremer B. Recent advances in hereditary spinocerebellar ataxias. J Neuropathol Exp Neurol 2005; 64:171-80. [PMID: 15804048 DOI: 10.1093/jnen/64.3.171] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In recent years, molecular genetic research has unraveled a major part of the genetic background of autosomal dominant and recessive spinocerebellar ataxias. These advances have also allowed insight in (some of) the pathophysiologic pathways assumed to be involved in these diseases. For the clinician, the expanding number of genes and genetic loci in these diseases and the enormous clinical heterogeneity of specific ataxia subtypes complicate management of ataxia patients. In this review, the clinical and neuropathologic features of the recently identified spinocerebellar ataxias are described, and the various molecular mechanisms that have been demonstrated to be involved in these disorders are discussed.
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56
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Viau M, Boulanger Y. Characterization of ataxias with magnetic resonance imaging and spectroscopy. Parkinsonism Relat Disord 2004; 10:335-51. [PMID: 15261875 DOI: 10.1016/j.parkreldis.2004.02.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2003] [Revised: 02/17/2004] [Accepted: 02/26/2004] [Indexed: 11/19/2022]
Abstract
A wide variety of autosomal transmitted ataxias exist and their ultimate characterization requires genetic testing. Common clinical characteristics among different ataxia types complicate the choice of the appropriate genetic test. Magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) generally show cerebellar or cerebral atrophy and perturbed metabolite levels which differ between ataxias. In order to help the clinician accurately identify the ataxia type, reported MRI and MRS data in different brain regions are summarized for more than 60 different types of autosomal inherited and sporadic ataxias.
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Affiliation(s)
- Martin Viau
- Département de Radiologie, Hôpital Saint-Luc, Centre Hospitalier de l'Université de Montréal, 1058 St-Denis, Montréal, Québec, Canada H2X 3J4
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57
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Schöls L, Bauer P, Schmidt T, Schulte T, Riess O. Autosomal dominant cerebellar ataxias: clinical features, genetics, and pathogenesis. Lancet Neurol 2004; 3:291-304. [PMID: 15099544 DOI: 10.1016/s1474-4422(04)00737-9] [Citation(s) in RCA: 666] [Impact Index Per Article: 33.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Autosomal dominant cerebellar ataxias are hereditary neurodegenerative disorders that are known as spinocerebellar ataxias (SCA) in genetic nomenclature. In the pregenomic era, ataxias were some of the most poorly understood neurological disorders; the unravelling of their molecular basis enabled precise diagnosis in vivo and explained many clinical phenomena such as anticipation and variable phenotypes even within one family. However, the discovery of many ataxia genes and loci in the past decade threatens to cause more confusion than optimism among clinicians. Therefore, the provision of guidance for genetic testing according to clinical findings and frequencies of SCA subtypes in different ethnic groups is a major challenge. The identification of ataxia genes raises hope that essential pathogenetic mechanisms causing SCA will become more and more apparent. Elucidation of the pathogenesis of SCA hopefully will enable the development of rational therapies for this group of disorders, which currently can only be treated symptomatically.
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Affiliation(s)
- Ludger Schöls
- Department of Neurology, University of Tuebingen, Germany
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58
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Takahashi H, Ishikawa K, Tsutsumi T, Fujigasaki H, Kawata A, Okiyama R, Fujita T, Yoshizawa K, Yamaguchi S, Tomiyasu H, Yoshii F, Mitani K, Shimizu N, Yamazaki M, Miyamoto T, Orimo T, Shoji S, Kitamura K, Mizusawa H. A clinical and genetic study in a large cohort of patients with spinocerebellar ataxia type 6. J Hum Genet 2004; 49:256-64. [PMID: 15362569 DOI: 10.1007/s10038-004-0142-7] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
In order to clarify the clinical and genetic features of SCA6, we retrospectively analyzed 140 patients. We observed an inverse correlation between the age of onset and the length of the expanded allele, and also between the age of onset and the sum of CAG repeats in the normal and the expanded alleles. The ages of onset of four homozygous patients correlated better with the sum of CAG repeats in both alleles rather than with the expanded allele calculated from heterozygous SCA6 subjects. Clinically, unsteadiness of gait was the main initial symptom, followed by vertigo and oscillopsia, and cerebellar signs were detected in nearly 100% of the patients. In contrast, extracerebellar signs were relatively mild and infrequent. The results of neuro-otological examination performed in 22 patients suggested the purely cerebellar abnormalities of ocular movements in nature. There was a close relationship between downbeat positioning nystagmus (DPN) and positioning vertigo, which became more common in the later stage. We conclude that total number of CAG repeat-units in both alleles is a good parameter for assessment of age of onset in SCA6 including homozygous patients. In addition, clinical and neuro-otological examinations suggested that SCA6 is a disease with predominantly cerebellar dysfunction.
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Affiliation(s)
- Hiroki Takahashi
- Department of Neurology and Neurological Science, Tokyo Medical and Dental University Graduate School of Medicine, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
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59
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Sasaki H, Yabe I, Tashiro K. The hereditary spinocerebellar ataxias in Japan. Cytogenet Genome Res 2003; 100:198-205. [PMID: 14526181 DOI: 10.1159/000072855] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2002] [Accepted: 03/03/2003] [Indexed: 11/19/2022] Open
Abstract
In Japan, multiple system atrophy (MSA) accounts for 40% of all spinocerebellar ataxias (SCAs) and hereditary disorders account for 30%. Among the latter, autosomal dominant disorders are common and recessive ataxias are rare. Although the frequency of SCA genotypes differs between geographic regions throughout Japan, SCA6, SCA3/MJD, and DRPLA are the three major disorders, while SCA7, SCA8, SCA10, SCA12, and SCA17 are infrequent or almost undetected. SCA1 predominantly occurs in the northern part of Japan. Overall, 20-40% of dominant SCAs are due to unknown mutations. From this cluster, pure cerebellar ataxias linked with the SCA4, SCA14, and SCA16 locus have been isolated. Among the recessive SCAs, patients with AVED and EAOH have been detected. However, FRDA associated with GAA repeat expansion in the frataxin gene has not been reported so far.
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Affiliation(s)
- H Sasaki
- Department of Neurology, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
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60
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Abstract
The autosomal dominant ataxias continue to bewilder us as the enormity of their genetic heterogeneity continues to unfold. The Human Genome Organization website now lists 22 such ataxias, not including dentatorubral-pallidoluysian atrophy. The early genetic discoveries in this field included several disorders caused by CAG repeat expansions within coding regions of the respective genes. More recent discoveries have included unstable expansions of nucleotide repeats in noncoding regions of genes as well as point mutations that have formed the basis of progressive dominant ataxias. This article summarizes the clinical and genetic features of the currently identified dominant ataxias.
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Affiliation(s)
- Christopher M Gomez
- Department of Neurology, University of Minnesota, Minneapolis, MN 55455, USA
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61
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Knight MA, Kennerson ML, Anney RJ, Matsuura T, Nicholson GA, Salimi-Tari P, Gardner RJM, Storey E, Forrest SM. Spinocerebellar ataxia type 15 (sca15) maps to 3p24.2-3pter: exclusion of the ITPR1 gene, the human orthologue of an ataxic mouse mutant. Neurobiol Dis 2003; 13:147-57. [PMID: 12828938 DOI: 10.1016/s0969-9961(03)00029-9] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
We have studied a large Australian kindred with a dominantly inherited pure cerebellar ataxia, SCA15. The disease is characterised by a very slow rate of progression in some family members, and atrophy predominantly of the superior vermis, and to a lesser extent the cerebellar hemispheres. Repeat expansion detection failed to identify either a CAG/CTG or ATTCT/AGAAT repeat expansions segregating with the disease in this family. A genome-wide scan revealed significant evidence for linkage to the short arm of chromosome 3. The highest two-point LOD score was obtained with D3S3706 (Z = 3.4, theta = 0.0). Haplotype analysis identified recombinants that placed the SCA15 locus within an 11.6-cM region flanked by the markers D3S3630 and D3S1304. The mouse syntenic region contains two ataxic mutants, itpr1-/- and opt, affecting the inositol 1,4,5-triphosphate type 1 receptor, ITPR1 gene. ITPR1 is predominantly expressed in the cerebellar Purkinje cells. Mutation analysis from two representative affected family members excluded the coding region of the ITPR1 gene from being involved in the pathogenesis of SCA15. Thus, the itpr1-/- and opt ITPR1 mouse mutants, which each result in ataxia, are not allelic to the human SCA15 locus.
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Affiliation(s)
- Melanie A Knight
- Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Melbourne, Australia
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62
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Chung MY, Lu YC, Cheng NC, Soong BW. A novel autosomal dominant spinocerebellar ataxia (SCA22) linked to chromosome 1p21-q23. Brain 2003; 126:1293-9. [PMID: 12764052 DOI: 10.1093/brain/awg130] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The autosomal dominant cerebellar ataxias (ADCA) are a clinically, pathologically and genetically heterogeneous group of disorders. Ten responsible genes have been identified for spinocerebellar ataxia types SCA1, SCA2, SCA3, SCA6, SCA7, SCA8, SCA10, SCA12 and SCA17, and dentatorubral pallidoluysian atrophy (DRPLA). The mutation is caused by an expansion of a CAG, CTG or ATTCT repeat sequence of these genes. Six additional loci, SCA4, SCA5, SCA11, SCA13, SCA14 and SCA16 have also been mapped. The growing heterogeneity of the autosomal dominant forms of these diseases shows that the genetic aetiologies of at least 20% of ADCA have yet to be elucidated. We ascertained and clinically characterized a four-generation Chinese pedigree segregating an autosomal dominant phenotype for cerebellar ataxia. Direct mutation analysis, linkage analysis for all known SCA loci and a genome-wide linkage study were performed. Direct mutation analysis excluded SCA1, 2, 3, 6, 7, 8, 10, 12, 17 and DRPLA, and genetic linkage analysis excluded SCA4, 5, 11, 13, 14 and 16. The genome-wide linkage study suggested linkage to a locus on chromosome 1p21-q23, with the highest two-point LOD score at D1S1167 (Zmax = 3.46 at theta = 0.00). Multipoint analysis and haplotype reconstruction traced this novel SCA locus (SCA22) to a 43.7-cM interval flanked by D1S206 and D1S2878 (Zmax = 3.78 under four liability classes, and 2.67 using affected-only method). The age at onset ranged from 10 to 46 years. All affected members had gait ataxia with variable features of dysarthria and hyporeflexia. Head MRI showed homogeneous atrophy of the cerebellum without involvement of the brainstem. In six parent-child pairs, median onset occurred 10 years earlier in offspring than in their parents, suggesting anticipation. This family is distinct from other families with SCA and is characterized by a slowly progressive, pure cerebellar ataxia.
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Affiliation(s)
- Ming-Yi Chung
- Department of Medical Research and Education, Taipei Veterans General Hospital, and Genome Research Centre, National Yang-Ming University, Taiwan
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63
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Matsuura T, Ashizawa T. Spinocerebellar ataxia type 10: a disease caused by a large ATTCT repeat expansion. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2003; 516:79-97. [PMID: 12611436 DOI: 10.1007/978-1-4615-0117-6_4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Tohru Matsuura
- Department of Neurology, Baylor College of Medicine and Veterans Affairs Medical Center, Houston, Texas 77030 USA
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64
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Chen DH, Brkanac Z, Verlinde CLMJ, Tan XJ, Bylenok L, Nochlin D, Matsushita M, Lipe H, Wolff J, Fernandez M, Cimino PJ, Bird TD, Raskind WH. Missense mutations in the regulatory domain of PKC gamma: a new mechanism for dominant nonepisodic cerebellar ataxia. Am J Hum Genet 2003; 72:839-49. [PMID: 12644968 PMCID: PMC1180348 DOI: 10.1086/373883] [Citation(s) in RCA: 193] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2002] [Accepted: 12/30/2002] [Indexed: 11/03/2022] Open
Abstract
We report a nonepisodic autosomal dominant (AD) spinocerebellar ataxia (SCA) not caused by a nucleotide repeat expansion that is, to our knowledge, the first such SCA. The AD SCAs currently comprise a group of > or =16 genetically distinct neurodegenerative conditions, all characterized by progressive incoordination of gait and limbs and by speech and eye-movement disturbances. Six of the nine SCAs for which the genes are known result from CAG expansions that encode polyglutamine tracts. Noncoding CAG, CTG, and ATTCT expansions are responsible for three other SCAs. Approximately 30% of families with SCA do not have linkage to the known loci. We recently mapped the locus for an AD SCA in a family (AT08) to chromosome 19q13.4-qter. A particularly compelling candidate gene, PRKCG, encodes protein kinase C gamma (PKC gamma), a member of a family of serine/threonine kinases. The entire coding region of PRKCG was sequenced in an affected member of family AT08 and in a group of 39 unrelated patients with ataxia not attributable to trinucleotide expansions. Three different nonconservative missense mutations in highly conserved residues in C1, the cysteine-rich region of the protein, were found in family AT08, another familial case, and a sporadic case. The mutations cosegregated with disease in both families. Structural modeling predicts that two of these amino acid substitutions would severely abrogate the zinc-binding or phorbol ester-binding capabilities of the protein. Immunohistochemical studies on cerebellar tissue from an affected member of family AT08 demonstrated reduced staining for both PKC gamma and ataxin 1 in Purkinje cells, whereas staining for calbindin was preserved. These results strongly support a new mechanism for neuronal cell dysfunction and death in hereditary ataxias and suggest that there may be a common pathway for PKC gamma-related and polyglutamine-related neurodegeneration.
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Affiliation(s)
- Dong-Hui Chen
- Departments of Psychiatry and Behavioral Sciences, Biochemistry, Biological Structure, Medicine, Pathology, and Neurology, University of Washington School of Medicine, and Geriatric Research, Education and Clinical Center and VISN 20 Mental Illness Research, Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle; and Department of Medicine, Ohio State University, Columbus
| | - Zoran Brkanac
- Departments of Psychiatry and Behavioral Sciences, Biochemistry, Biological Structure, Medicine, Pathology, and Neurology, University of Washington School of Medicine, and Geriatric Research, Education and Clinical Center and VISN 20 Mental Illness Research, Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle; and Department of Medicine, Ohio State University, Columbus
| | - Christophe L. M. J. Verlinde
- Departments of Psychiatry and Behavioral Sciences, Biochemistry, Biological Structure, Medicine, Pathology, and Neurology, University of Washington School of Medicine, and Geriatric Research, Education and Clinical Center and VISN 20 Mental Illness Research, Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle; and Department of Medicine, Ohio State University, Columbus
| | - Xiao-Jian Tan
- Departments of Psychiatry and Behavioral Sciences, Biochemistry, Biological Structure, Medicine, Pathology, and Neurology, University of Washington School of Medicine, and Geriatric Research, Education and Clinical Center and VISN 20 Mental Illness Research, Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle; and Department of Medicine, Ohio State University, Columbus
| | - Laura Bylenok
- Departments of Psychiatry and Behavioral Sciences, Biochemistry, Biological Structure, Medicine, Pathology, and Neurology, University of Washington School of Medicine, and Geriatric Research, Education and Clinical Center and VISN 20 Mental Illness Research, Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle; and Department of Medicine, Ohio State University, Columbus
| | - David Nochlin
- Departments of Psychiatry and Behavioral Sciences, Biochemistry, Biological Structure, Medicine, Pathology, and Neurology, University of Washington School of Medicine, and Geriatric Research, Education and Clinical Center and VISN 20 Mental Illness Research, Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle; and Department of Medicine, Ohio State University, Columbus
| | - Mark Matsushita
- Departments of Psychiatry and Behavioral Sciences, Biochemistry, Biological Structure, Medicine, Pathology, and Neurology, University of Washington School of Medicine, and Geriatric Research, Education and Clinical Center and VISN 20 Mental Illness Research, Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle; and Department of Medicine, Ohio State University, Columbus
| | - Hillary Lipe
- Departments of Psychiatry and Behavioral Sciences, Biochemistry, Biological Structure, Medicine, Pathology, and Neurology, University of Washington School of Medicine, and Geriatric Research, Education and Clinical Center and VISN 20 Mental Illness Research, Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle; and Department of Medicine, Ohio State University, Columbus
| | - John Wolff
- Departments of Psychiatry and Behavioral Sciences, Biochemistry, Biological Structure, Medicine, Pathology, and Neurology, University of Washington School of Medicine, and Geriatric Research, Education and Clinical Center and VISN 20 Mental Illness Research, Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle; and Department of Medicine, Ohio State University, Columbus
| | - Magali Fernandez
- Departments of Psychiatry and Behavioral Sciences, Biochemistry, Biological Structure, Medicine, Pathology, and Neurology, University of Washington School of Medicine, and Geriatric Research, Education and Clinical Center and VISN 20 Mental Illness Research, Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle; and Department of Medicine, Ohio State University, Columbus
| | - P. J. Cimino
- Departments of Psychiatry and Behavioral Sciences, Biochemistry, Biological Structure, Medicine, Pathology, and Neurology, University of Washington School of Medicine, and Geriatric Research, Education and Clinical Center and VISN 20 Mental Illness Research, Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle; and Department of Medicine, Ohio State University, Columbus
| | - Thomas D. Bird
- Departments of Psychiatry and Behavioral Sciences, Biochemistry, Biological Structure, Medicine, Pathology, and Neurology, University of Washington School of Medicine, and Geriatric Research, Education and Clinical Center and VISN 20 Mental Illness Research, Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle; and Department of Medicine, Ohio State University, Columbus
| | - Wendy H. Raskind
- Departments of Psychiatry and Behavioral Sciences, Biochemistry, Biological Structure, Medicine, Pathology, and Neurology, University of Washington School of Medicine, and Geriatric Research, Education and Clinical Center and VISN 20 Mental Illness Research, Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle; and Department of Medicine, Ohio State University, Columbus
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65
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Affiliation(s)
- Patrick J Morrison
- Department of Medical Genetics, Belfast City Hospital Trust, Belfast BT9 7AB, Northern Ireland, UK.
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66
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Gasser T, Bressman S, Dürr A, Higgins J, Klockgether T, Myers RH. State of the art review: molecular diagnosis of inherited movement disorders. Movement Disorders Society task force on molecular diagnosis. Mov Disord 2003; 18:3-18. [PMID: 12518296 DOI: 10.1002/mds.10338] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
This review is designed to provide practical help for the clinical neurologist to make appropriate use of the possibilities of molecular diagnosis of inherited movement disorders. Huntington's disease, Parkinson's disease and parkinsonian syndromes, ataxias, Wilson disease, essential tremor, dystonias, and other genetic diseases associated with a variety of movement disorders are considered separately.
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Affiliation(s)
- Thomas Gasser
- Department of Neurology, Klinikum Grosshadern, Ludwig-Maximilians-University, Munich, Germany.
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67
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Zhao Y, Tan EK, Law HY, Yoon CS, Wong MC, Ng I. Prevalence and ethnic differences of autosomal-dominant cerebellar ataxia in Singapore. Clin Genet 2002; 62:478-81. [PMID: 12485197 DOI: 10.1034/j.1399-0004.2002.620610.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
We report the prevalence and ethnic differences of autosomal-dominant cerebellar ataxia (ADCA) in Singapore. Amongst 204 patients with ataxia who underwent genetic testing for dentatorubral-pallidoluysian atrophy (DRPLA) and for spinocerebellar ataxias (SCA) 1, 2, 3, 6, 7, 8, 10 and 12, 58 (28.4%) patients from 36 families tested positive. SCA 3 was identified in 31 (53.4%) patients from 15 families, SCA 2 in 17 (29.3%) patients from 12 families and SCA 1 in four (6.9%) patients from four families. Other SCA subtypes were rare. SCA 2 was the only subtype identified amongst ethnic Malay and ethnic Indian families. The estimated prevalence of ADCA in Singaporean families was at least 1 : 27,000. Based on the history and ancestry of Singaporeans, our study supported a founder effect for specific SCA subtypes and the association of ethnicity-specific SCA subtypes. Our findings suggest that SCA 2 is relatively common amongst the Malay race and that priority testing for SCA 3 and SCA 2 for ethnic Chinese, and SCA 2 for ethnic Malay, may be cost effective and relevant for the region.
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Affiliation(s)
- Y Zhao
- Department of Clinical Research, Singapore General Hospital, Singapore.
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68
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Vuillaume I, Devos D, Schraen-Maschke S, Dina C, Lemainque A, Vasseur F, Bocquillon G, Devos P, Kocinski C, Marzys C, Destée A, Sablonnière B. A new locus for spinocerebellar ataxia (SCA21) maps to chromosome 7p21.3-p15.1. Ann Neurol 2002; 52:666-70. [PMID: 12402269 DOI: 10.1002/ana.10344] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We investigated a French family with a new type of autosomal dominant spinocerebellar ataxia that was excluded from all previously identified genes and loci. The patients exhibited a slowly progressive gait and limb ataxia variably associated with akinesia, rigidity, tremor, and hyporeflexia. A mild cognitive impairment also was observed in some cases. We performed a genomewide search and found significant evidence for linkage to chromosome 7p21.3-p15.1. Analysis of key recombinants and haplotype reconstruction traced this novel spinocerebellar ataxia locus to a 24cM interval flanked by D7S2464 and D7S516.
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Affiliation(s)
- Isabelle Vuillaume
- Unité Fonctionnelle de Neurobiologie, Laboratoire de Biochimie et Biologie moléculaire, Hôpital R. Salengro, Centre Hospitalier Régional et Universitaire, Boulevard du Professeur Leclerc, 59037 Lille Cedex, France
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69
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Abstract
In the past decade, the genetic etiologies accounting for most cases of adult-onset dominant cerebellar ataxia have been discovered. This group of disorders, generally referred to as the spinocerebellar ataxias (SCAs), can now be classified by a simple genetic nosology, essentially a sequential list in which each new SCA is given a number. However, recent advances in the elucidation of SCA pathogenesis provide the opportunity to subclassify the disorders into three discrete groups based on pathogenesis: 1) the polyglutamine disorders, SCAs 1, 2, 3, 7, and 17, which result from proteins with toxic stretches of polyglutamine; 2) the channelopathies, SCA6 and episodic ataxia types 1 and 2 (EA1 and EA2), which result from disruption of calcium or potassium channel function; and 3) the gene expression disorders, SCAs 8, 10, and 12, which result from repeat expansions outside of coding regions that may quantitatively alter gene expression. SCAs 4, 5, 9, 11, 13-16, 19, 21, and 22 are of unknown etiology, and may or may not fit into one of these three groups. At present, most diagnostic and therapeutic strategies apply equally to all of the SCAs. Therapy specific for individual diseases or types of diseases is a realistic goal in the foreseeable future.
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Affiliation(s)
- Russell L Margolis
- Laboratory of Genetic Neurobiology, Division of Neurobiology, Department of Psychiatry and Program in Cellular and Molecular Medicine, Johns Hopkins University School of Medicine, 600 North Wolfe Street, Baltimore, MD 21287, USA.
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70
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Abstract
Advances in molecular genetics have led to identification of an increasing number of genes responsible for inherited ataxic disorders. Consequently, DNA testing has become a powerful method to unambiguously establish the diagnosis in some of these disorders; however, there are limitations in this approach. Furthermore, the ethical, social, legal and psychological implications of the genetic test results are complex, necessitating appropriate counseling. This article intends to help the practicing neurologist clinically differentiate these disorders, choose appropriate genetic tests, and recognize the importance of counseling.
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Affiliation(s)
- Alberto L Rosa
- Universidad de Córdoba, Laboratory of Neurogenetics, Institute for Medical Research Mercedes y Martín Ferreyra-INIMEC, Carrer Researcher of the National Research Council (CONICET), Córdoba, Argentina
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71
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Mao R, Aylsworth AS, Potter N, Wilson WG, Breningstall G, Wick MJ, Babovic-Vuksanovic D, Nance M, Patterson MC, Gomez CM, Snow K. Childhood-onset ataxia: testing for large CAG-repeats in SCA2 and SCA7. AMERICAN JOURNAL OF MEDICAL GENETICS 2002; 110:338-45. [PMID: 12116207 DOI: 10.1002/ajmg.10467] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Infantile- and juvenile-onset spinal cerebellar ataxia (SCA) is associated with expansion of 130 to more than 200 CAG-repeats in the SCA2 and SCA7 genes. Routine clinical assays for SCA2 and SCA7, which use polymerase chain reaction (PCR) and denaturing PAGE (polyacrylamide gel electrophoresis), will not reliably detect such large expansions. An assay based on separation of PCR products on an agarose gel, blotting, and hybridization with a (CAG)6 oligonucleotide probe was used to test DNA from individuals more than 10 years of age who had a possible diagnosis of SCA. Among 25 cases, the PCR-blot assay confirmed the presence of SCA2 expansions between 230 and 500 repeats in four unrelated individuals, but did not detect any cases of extreme expansion in the SCA7 gene. The PCR-blot assay provides reliable detection of extreme expansion mutations. Routine incorporation of this assay in clinical laboratories may reveal that infantile-juvenile forms of SCA2 and SCA7 are more prevalent than previously recognized.
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Affiliation(s)
- Rong Mao
- Division of Laboratory Genetics, Mayo Clinic, Rochester, Minnesota 55905, USA
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72
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Maruyama H, Izumi Y, Morino H, Oda M, Toji H, Nakamura S, Kawakami H. Difference in disease-free survival curve and regional distribution according to subtype of spinocerebellar ataxia: a study of 1,286 Japanese patients. AMERICAN JOURNAL OF MEDICAL GENETICS 2002; 114:578-83. [PMID: 12116198 DOI: 10.1002/ajmg.10514] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Expansions of trinucleotide repeats have been discovered in spinocerebellar ataxia (SCA) types 1, 2, 6, 7, 12, and 17, Machado-Joseph disease (MJD/SCA3), and dentatorubropallidoluysian atrophy (DRPLA). However, the frequency of familial SCA in Japan remains unclear. The number of trinucleotide repeats was determined for 1,286 patients. Three hundred and thirty families (523 cases) were autosomal dominant group (A), and 165 families were positive for family history but not autosomal dominant group (B), while the remaining 598 cases were the sporadic group (C). The frequency of SCA subtypes in autosomal dominant group was: 1) 5.5% for SCA1; 2) 2.4% for SCA2; 3) 27.6% for MJD/SCA3; 4) 25.5% for SCA6; 5) 0.3% for SCA17; and 6) 7.3% for DRPLA. Abnormal expansion of SCA12 was not detected. Another 31.5% of the patients in the autosomal dominant group had unknown genetic abnormalities. Within group B, SCA6 was the most prominent and within the sporadic group MJD/SCA3 and SCA6 were the most common subtypes observed. The disease-free survival curve of SCA6 was different from that of other SCAs and the mean age at onset for SCA6 was found to be later than that of the other types. Regional differences were observed in the relative rate of SCA subtypes. MJD/SCA3 appears more common in the Kanto and Kyushu districts of Japan, whereas SCA6 is most common in the Chugoku district. In order to establish an effective social welfare system for SCA patients, clinical course and regional differences in the prevalence of SCA subtypes must be taken into consideration.
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Affiliation(s)
- Hirofumi Maruyama
- Third Department of Internal Medicine, Hiroshima University School of Medicine, Hiroshima, Japan
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73
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Holmes SE, Hearn EO, Ross CA, Margolis RL. SCA12: an unusual mutation leads to an unusual spinocerebellar ataxia. Brain Res Bull 2001; 56:397-403. [PMID: 11719278 DOI: 10.1016/s0361-9230(01)00596-2] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Spinocerebellar ataxia type 12 (SCA12) is an autosomal dominant neurodegenerative disorder which has been described in pedigrees of German American and Indian descent. The phenotype typically begins with tremor in the fourth decade, progressing to include ataxia and other cerebellar and cortical signs. SCA12 is associated with an expansion of a CAG repeat in the 5' region of the gene PPP2R2B which encodes a brain-specific regulatory subunit of the protein phosphatase PP2A. The repeat size ranges from 55 to 78 triplets in the mutant allele of affected individuals, and from 9 to 28 triplets in normal alleles. It is possible that an expansion mutation in PPP2R2B may influence PPP2R2B expression, perhaps altering the activity of PP2A, an enzyme implicated in multiple cellular functions, including cell cycle regulation, tau phosphorylation, and apoptosis.
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Affiliation(s)
- S E Holmes
- Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA.
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74
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Rasmussen A, Matsuura T, Ruano L, Yescas P, Ochoa A, Ashizawa T, Alonso E. Clinical and genetic analysis of four Mexican families with spinocerebellar ataxia type 10. Ann Neurol 2001; 50:234-9. [PMID: 11506407 DOI: 10.1002/ana.1081] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Spinocerebellar ataxia type 10 (SCA10) is an autosomal dominant disorder caused by expansion of an unstable ATTCT repeat. SCA10 has been described as a pure cerebellar syndrome accompanied by seizures and has been recognized only in families of Mexican origin. We describe clinical and molecular findings of 18 patients in four Mexican families with SCA10. Affected individuals had an average age at onset of 26.7 years (range 14-44 years) and ATTCT repeats ranging from 920 to 4,140 repeats. We could not detect significant anticipation or correlation between repeat size and age at onset, probably due to the small sample size. In addition to pure cerebellar ataxia and seizures, patients often showed soft pyramidal signs, ocular dyskinesia, cognitive impairment, and/or behavioral disturbances. Brain magnetic resonance imaging showed predominant cerebellar atrophy, and nerve conduction studies indicated polyneuropathy in 66% of patients. One family showed hepatic, cardiac, and hematological abnormalities in affected members. These findings suggest that a wide range of tissues may be affected in SCA10, including those outside of the cerebellum and cerebral cortex.
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Affiliation(s)
- A Rasmussen
- Department of Neurogenetics and Molecular Biology, Instituto Nacional de Neurología y Neurocirugía Manuel Velasco Suárez, Mexico City, Mexico
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75
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Abstract
The last decade has seen great changes in the diagnosis of inherited ataxias. Previously mysterious diseases are now recognized to be caused by specific mutations for which genetic screening is readily available. In many cases, the discovery of the molecular basis has broadened the definition of possible clinical manifestations of particular inherited ataxias. The type of mutation underlying the more common forms of inherited ataxia-unstable trinucleotide repeat expansions-helps to explain some of the unusual features of these diseases. This article reviews recent genetic advances in ataxia. The aim is not to present an exhaustive summary but rather to provide guidance in evaluating ataxia, particularly with respect to recent molecular genetic findings.
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Affiliation(s)
- H Paulson
- Department of Neurology, University of Iowa College of Medicine, Iowa City, Iowa 52242-1101, USA.
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