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Sena LS, Furtado GV, Pedroso JL, Barsottini O, Cornejo-Olivas M, Nóbrega PR, Braga Neto P, Soares DMB, Vargas FR, Godeiro C, Medeiros PFVD, Camejo C, Toralles MBP, Fagundes NJR, Jardim LB, Saraiva-Pereira ML. Spinocerebellar ataxia type 2 has multiple ancestral origins. Parkinsonism Relat Disord 2024; 120:105985. [PMID: 38181536 DOI: 10.1016/j.parkreldis.2023.105985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 12/13/2023] [Accepted: 12/28/2023] [Indexed: 01/07/2024]
Abstract
INTRODUCTION Spinocerebellar ataxia type 2 (SCA2) is a dominant neurodegenerative disorder due to expansions of a CAG repeat tract (CAGexp) at the ATXN2 gene. Previous studies found only one ancestral haplotype worldwide, with a C allele at rs695871. This homogeneity was unexpected, given the severe anticipations related to SCA2. We aimed to describe informative ancestral haplotypes found in South American SCA2 families. METHODS Seventy-seven SCA2 index cases were recruited from Brazil, Peru, and Uruguay; 263 normal chromosomes were used as controls. The SNPs rs9300319, rs3809274, rs695871, rs1236900 and rs593226, and the STRs D12S1329, D12S1333, D12S1672 and D12S1332, were used to reconstruct haplotypes. RESULTS Eleven ancestral haplotypes were found in SCA2 families. The most frequent ones were A-G-C-C-C (46.7 % of families), G-C-C-C-C (24.6 %) and A-C-C-C-C (10.3 %) and their mean (sd) CAGexp were 41.68 (3.55), 40.42 (4.11) and 45.67 (9.70) (p = 0.055), respectively. In contrast, the mean (sd) CAG lengths at normal alleles grouped per haplotypes G-C-G-A-T, A-G-C-C-C and G-C-C-C-C were 22.97 (3.93), 23.85 (3.59), and 30.81 (4.27) (p < 0.001), respectively. The other SCA2 haplotypes were rare: among them, a G-C-G-A-T lineage was found, evidencing a G allele in rs695871. CONCLUSION We identified several distinct ancestral haplotypes in SCA2 families, including an unexpected lineage with a G allele at rs695871, a variation never found in hundreds of SCA2 patients studied worldwide. SCA2 has multiple origins in South America, and more studies should be done in other regions of the world.
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Affiliation(s)
- Lucas Schenatto Sena
- Programa de Pós-Graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves, 9500, 91501-970, Porto Alegre, Brazil; Centros de Pesquisa Clínica e Experimental, Hospital de Clínicas de Porto Alegre, Rua Ramiro Barcelos 2340, 90035-903, Porto Alegre, Brazil.
| | - Gabriel Vasata Furtado
- Centros de Pesquisa Clínica e Experimental, Hospital de Clínicas de Porto Alegre, Rua Ramiro Barcelos 2340, 90035-903, Porto Alegre, Brazil
| | - José Luiz Pedroso
- Universidade Federal do Estado de São Paulo, Rua Pedro de Toledo 650, 04039-031, São Paulo, Brazil
| | - Orlando Barsottini
- Universidade Federal do Estado de São Paulo, Rua Pedro de Toledo 650, 04039-031, São Paulo, Brazil
| | - Mario Cornejo-Olivas
- Neurogenetics Working Group, Universidad Cientifica del Sur, 19 Panamericana S Avenue, 15067, Lima, 15067, Peru; Neurogenetics Research Center, Instituto Nacional de Ciencias Neurológicas, 1271 Ancas St, 15003, Lima, Peru
| | - Paulo Ribeiro Nóbrega
- Setor de Neurologia, Departamento de Medicina Clínica, Faculdade de Medicina, Universidade Federal do Ceará, Rua Professor Costa Mendes, 1608, 60430-140, Fortaleza, CE, Brazil; Centro Universitário Christus, Rua Alexandre Baraúna 949, 60430-160, Fortaleza, CE, Brazil
| | - Pedro Braga Neto
- Setor de Neurologia, Departamento de Medicina Clínica, Faculdade de Medicina, Universidade Federal do Ceará, Rua Professor Costa Mendes, 1608, 60430-140, Fortaleza, CE, Brazil; Curso de Medicina, Centro de Ciências da Saúde, Universidade Estadual do Ceará, Avenida Dr. Silas Munguba, 1700, 60714-903, Fortaleza, CE, Brazil
| | - Danyela Martins Bezerra Soares
- Curso de Medicina, Centro de Ciências da Saúde, Universidade Estadual do Ceará, Avenida Dr. Silas Munguba, 1700, 60714-903, Fortaleza, CE, Brazil
| | - Fernando Regla Vargas
- Departamento de Genética e Biologia Molecular, Universidade Federal do Estado do Rio de Janeiro, Rua Frei Caneca 94, 20211-010, Rio de Janeiro, Brazil; Laboratório de Epidemiologia de Malformações Congênitas, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Avenida Brasil 4365, 21040-900, Rio de Janeiro, Brazil
| | - Clecio Godeiro
- Departamento de Medicina Integrada, Hospital Universitário Onofre Lopes, Avenida Nilo Peçanha, 59012-300, Natal, Brazil
| | - Paula Frassinetti Vasconcelos de Medeiros
- Unidade Acadêmica de Medicina, Hospital Universitário Alcides Carneiro, Universidade Federal de Campina Grande, Rua Carlos Chagas S/n, 58107-670, Campina Grande, Brazil
| | - Claudia Camejo
- Facultad de Medicina. Universidad de La República, Avenida General Flores 3461, 11700, Montevideo, Uruguay
| | | | - Nelson Jurandi Rosa Fagundes
- Programa de Pós-Graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves, 9500, 91501-970, Porto Alegre, Brazil; Departamento de Genética, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves, 9500, 91501-970, Porto Alegre, Brazil
| | - Laura Bannach Jardim
- Programa de Pós-Graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves, 9500, 91501-970, Porto Alegre, Brazil; Centros de Pesquisa Clínica e Experimental, Hospital de Clínicas de Porto Alegre, Rua Ramiro Barcelos 2340, 90035-903, Porto Alegre, Brazil; Serviço de Genética Médica, Hospital de Clínicas de Porto Alegre, Rua Ramiro Barcelos 2340, 90.035-903, Brazil; Departamento de Medicina Interna, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos 2400, 90035-002, Porto Alegre, Brazil
| | - Maria Luiza Saraiva-Pereira
- Programa de Pós-Graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves, 9500, 91501-970, Porto Alegre, Brazil; Centros de Pesquisa Clínica e Experimental, Hospital de Clínicas de Porto Alegre, Rua Ramiro Barcelos 2340, 90035-903, Porto Alegre, Brazil; Serviço de Genética Médica, Hospital de Clínicas de Porto Alegre, Rua Ramiro Barcelos 2340, 90.035-903, Brazil; Departamento de Bioquímica, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos 2600, 90035-003, Porto Alegre, Brazil
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Sena LS, Dos Santos Pinheiro J, Hasan A, Saraiva-Pereira ML, Jardim LB. Spinocerebellar ataxia type 2 from an evolutionary perspective: Systematic review and meta-analysis. Clin Genet 2021; 100:258-267. [PMID: 33960424 DOI: 10.1111/cge.13978] [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: 03/02/2021] [Revised: 04/19/2021] [Accepted: 05/05/2021] [Indexed: 01/27/2023]
Abstract
Dominant diseases due to expanded CAG repeat tracts, such as spinocerebellar ataxia type 2 (SCA2), are prone to anticipation and worsening of clinical picture in subsequent generations. There is insufficient data about selective forces acting on the maintenance of these diseases in populations. We made a systematic review and meta-analysis on the effect of the CAG length over age at onset, instability of transmissions, anticipation, de novo or sporadic cases, fitness, segregation of alleles, and ancestral haplotypes. The correlation between CAG expanded and age at onset was r2 = 0.577, and transmission of the mutant allele was associated with an increase of 2.42 CAG repeats in the next generation and an anticipation of 14.62 years per generation, on average. One de novo and 18 sporadic cases were detected. Affected SCA2 individuals seem to have more children than controls. The expanded allele was less segregated than the 22-repeat allele in children of SCA2 subjects. Several ancestral SCA2 haplotypes were published. Data suggest that SCA2 lineages may tend to disappear eventually, due to strong anticipation phenomena. Whether or not the novel cases come from common haplotypes associated with a predisposition to further expansions is a question that needs to be addressed by future studies.
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Affiliation(s)
- Lucas Schenatto Sena
- Programa de Pós-Graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Centros de Pesquisa Clínica e Experimental, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
| | - Jordânia Dos Santos Pinheiro
- Centros de Pesquisa Clínica e Experimental, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil.,Faculdade de Farmácia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Ali Hasan
- Programa de Pós-Graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Centros de Pesquisa Clínica e Experimental, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
| | - Maria Luiza Saraiva-Pereira
- Programa de Pós-Graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Centros de Pesquisa Clínica e Experimental, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil.,Departamento de Bioquímica, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Instituto de Genética Médica Populacional, Porto Alegre, Brazil.,Serviço de Genética Médica, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
| | - Laura Bannach Jardim
- Programa de Pós-Graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Centros de Pesquisa Clínica e Experimental, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil.,Instituto de Genética Médica Populacional, Porto Alegre, Brazil.,Serviço de Genética Médica, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil.,Departamento de Medicina Interna, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
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Non-ataxic manifestations of Spinocerebellar ataxia-2, their determinants and predictors. J Neurol Sci 2018; 394:14-18. [PMID: 30196130 DOI: 10.1016/j.jns.2018.08.024] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 08/04/2018] [Accepted: 08/26/2018] [Indexed: 02/07/2023]
Abstract
INTRODUCTION To evaluate the non-ataxic clinical manifestations in genetically proven Spinocerebellar ataxia 2 (SCA2) and identify their determinants and predictors. METHODS Seventy-three subjects with genetically proven SCA2 were evaluated clinically for the common non-ataxic manifestations. Based on the presence or absence of non-ataxic manifestations, patients were classified into groups and then compared for significant differences in the CAG repeat length, age at onset (AAO), duration of disease, and ataxia rating score. Predictors of non-ataxic symptoms were identified using multivariable binary logistic regression. RESULTS The most common non-ataxic clinical manifestations were peripheral neuropathy, extrapyramidal features, pyramidal signs, cognitive impairment and lower motor neuron signs. The CAG repeat length was inversely related to the AAO of symptoms (r = -0.46, p < .001). Patients with peripheral neuropathy and psychiatric symptoms had earlier AAO. Patients with cognitive impairment and extrapyramidal symptoms had higher CAG repeat length whereas presence of lower motor neuron signs was more common in patients with lower CAG repeat length. CONCLUSION The lower strength of association between CAG repeat length and AAO in our cohort suggests the presence of additional factors underlying the variability in AAO. Both CAG repeat length and AAO were identified as significant determinants and predictors of non-ataxic symptoms.
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Genetic testing for clinically suspected spinocerebellar ataxias: report from a tertiary referral centre in India. J Genet 2018. [DOI: 10.1007/s12041-018-0911-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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Tensini FS, Pedroso JL, Barsottini OGP, Teive HAG. Professor Wadia's contributions to neurology and spinocerebellar ataxia type 2. ARQUIVOS DE NEURO-PSIQUIATRIA 2017; 75:255-257. [PMID: 28489147 DOI: 10.1590/0004-282x20170008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2016] [Accepted: 12/06/2016] [Indexed: 06/07/2023]
Abstract
The authors present a historical review of the seminal contributions of Professor N. H. Wadia (1925-2016) to neurology, in particular, the first description of spinocerebellar ataxia type 2.
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Affiliation(s)
- Fernando Spina Tensini
- Universidade Federal do Paraná, Hospital de Clínicas, Departamento de Medicina Interna, Unidade de Distúrbios do Movimento, Serviço de Neurologia, Curitiba PR, Brasil
| | - José Luiz Pedroso
- Universidade Federal de São Paulo,Divisão de Neurologia Geral e Unidade de Ataxia, Departamento de Neurologia, São Paulo SP, Brasil
| | - Orlando G P Barsottini
- Universidade Federal de São Paulo,Divisão de Neurologia Geral e Unidade de Ataxia, Departamento de Neurologia, São Paulo SP, Brasil
| | - Hélio A G Teive
- Universidade Federal do Paraná, Hospital de Clínicas, Departamento de Medicina Interna, Unidade de Distúrbios do Movimento, Serviço de Neurologia, Curitiba PR, Brasil
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Abstract
Autosomal dominant cerebellar ataxias, frequently referred to as spinocerebellar ataxias (SCAs) have been under intense scientific research limelight since expansions of coded CAG trinucleotide repeats were demonstrated to cause several dominantly inherited SCAs. The number of new SCA loci has expanded dramatically in recent years. At least ten genes have been identified for SCAs 1, 2, 3, 6, 7, 8, 10, 12, 17, dentatorubral-pallidoluysian atrophy (DRPLA), and six loci responsible for SCAs 4, 5, 11,13, 14, and 16 have been mapped. Genetic testing is essential for diagnosis due to the overlapping and varied phenotypic features of the different SCAs. While there is no effective treatment available, genetic counseling is important for addressing the many ethical, social, legal, and psychological issues facing SCA patients. Researchers have recently provided valuable information on the pathogenesis of the disease and hopefully a cure will be available in the near future.
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Affiliation(s)
- E K Tan
- Department of Neurology, Singapore General Hospital, Singapore.
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Sequeiros J, Martins S, Silveira I. Epidemiology and population genetics of degenerative ataxias. HANDBOOK OF CLINICAL NEUROLOGY 2012; 103:227-51. [PMID: 21827892 DOI: 10.1016/b978-0-444-51892-7.00014-0] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Jorge Sequeiros
- Institute of Molecular and Cell Biology, University of Porto, Portugal.
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Ramos EM, Martins S, Alonso I, Emmel VE, Saraiva-Pereira ML, Jardim LB, Coutinho P, Sequeiros J, Silveira I. Common origin of pure and interrupted repeat expansions in spinocerebellar ataxia type 2 (SCA2). Am J Med Genet B Neuropsychiatr Genet 2010; 153B:524-531. [PMID: 19676102 DOI: 10.1002/ajmg.b.31013] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The spinocerebellar ataxia type 2 (SCA2) is an autosomal dominant neurodegenerative disease characterized by gait and limb ataxia. This disease is caused by the expansion of a (CAG)(n) located in the ATXN2, that encodes a polyglutamine tract of more than 34 repeats. Lately, alleles with 32-33 CAGs have been associated to late-onset disease cases. Repeat interruptions by CAA triplets are common in normal alleles, while expanded alleles usually contain a pure repeat tract. To investigate the mutational origin and the instability associated to the ATXN2 repeat, we performed an extensive haplotype study and sequencing of the CAG/CAA repeat, in a cohort of families of different geographic origins and phenotypes. Our results showed (1) CAA interruptions also in expanded ATXN2 alleles; (2) that pathological CAA interrupted alleles shared an ancestral haplotype with pure expanded alleles; and (3) higher genetic diversity in European SCA2 families, suggesting an older European ancestry of SCA2. In conclusion, we found instability towards expansion in interrupted ATXN2 alleles and a shared ancestral ATXN2 haplotype for pure and interrupted expanded alleles; this finding has strong implications in mutation diagnosis and counseling. Our results indicate that interrupted alleles, below the pathological threshold, may be a reservoir of mutable alleles, prone to expansion in subsequent generations, leading to full disease mutation.
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Affiliation(s)
- Eliana Marisa Ramos
- UnIGENe, IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Sandra Martins
- UnIGENe, IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.,IPATIMUP-Instituto de Patologia e Imunologia Molecular da Universidade do Porto, Porto, Portugal
| | - Isabel Alonso
- UnIGENe, IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | | | | | | | - Paula Coutinho
- UnIGENe, IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.,Hospital São Sebastião, Feira, Portugal
| | - Jorge Sequeiros
- UnIGENe, IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.,ICBAS - Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Isabel Silveira
- UnIGENe, IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
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Sinha KK, Worth PF, Jha DK, Sinha S, Stinton VJ, Davis MB, Wood NW, Sweeney MG, Bhatia KP. Autosomal dominant cerebellar ataxia: SCA2 is the most frequent mutation in eastern India. J Neurol Neurosurg Psychiatry 2004; 75:448-52. [PMID: 14966163 PMCID: PMC1738947 DOI: 10.1136/jnnp.2002.004895] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVE Spinocerebellar ataxia type 2 (SCA2) has been reported as the commonest dominant hereditary ataxia in India. However, India is an ethnically and religiously diverse population. Previous studies have not clearly indicated exact ethnic and religious origins, and must therefore be interpreted with caution. The purpose of this study was to determine the prevalence of different SCA mutations in a relatively homogeneous population from eastern India. METHODS We identified 28 families with autosomal dominant cerebellar ataxia from eastern India. Each underwent full clinical evaluation and were analysed for the presence of SCA1, SCA2, SCA3, SCA6, SCA7, SCA8, SCA12, and SCA17 mutations. In addition, haplotype analysis was carried out in seven of the 16 families with SCA2. RESULTS Seven patients from four (14%) families were positive for an expansion in SCA1 and 26 patients from 16 (57%) families were positive for an expansion in SCA2. No mutations were detected in the remaining eight families (29%). Most of the SCA1 and SCA2 families were Hindu from the state of Bihar. Five out of 26 SCA2 patients in this study did not have slow saccades. In addition, four of seven SCA1 patients had slow saccades. We found an association between the SCA2 CAG repeat expansion and the 285 base pair (bp) allele of microsatellite marker D12S1672, and also data supportive of the association between the expansion and the 225 bp allele of D12S1333, which has been previously described. CONCLUSIONS We conclude that (1) although slow ocular saccades are highly suggestive of SCA2, that they are not universal, nor are they exclusive to this disorder and (2) SCA2 is likely to be the commonest dominant ataxia in eastern India, with further evidence for a founder effect.
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Affiliation(s)
- K K Sinha
- Department of Clinical Neurology, Institute of Neurology, Queen Square, London WC1N 3BG, UK
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Chakravarty A, Mukherjee SC. Autosomal dominant cerebellar ataxias in ethnic Bengalees in West Bengal - an Eastern Indian state. Acta Neurol Scand 2002; 105:202-8. [PMID: 11886365 DOI: 10.1034/j.1600-0404.2002.1o054.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND Phenotypic and genotypic patterns of a hereditary disease in a large multiethnic country like India need to be studied in relation to geographical location and ethnicity of the population. The few reported studies from India on dominant ataxias (ADCA) have mostly been conducted on multiethnic populations and hence may not reflect the patterns observed in specific ethnic groups or geographical locations. The present study attempted to look into the patterns of ADCA amongst ethnic Bengalee patients hailing from the eastern Indian state of West Bengal. MATERIAL AND METHODS Between mid-1996 and mid-2000, in a clinic based study, 37 cases (from 14 families) with ADCA were studied. This included 33 affected and four asymptomatic members with abnormal physical signs. Genotypic analyses were performed on more than one affected member from each family. Clinical, neuroradiological and electrophysiological aspects were studied. OBSERVATIONS Genotype analysis revealed: two families with SCA-1,4 families with SCA2,5 families with SCA3 and three families with undetermined genotype. Of the latter, phenotypically 2 were of ADCA 1 and one of ADCA 2 type. No clear preponderance of one particular genotype over another was observed. We noted significant intra- and interfamily variations in phenotype within the same genotype form as well as overlapping of clinical signs between different genotypes. Slow saccadic eye movements and peripheral neuropathy were not seen consistently in our ethnic Bengalee subjects with SCA2 genotypes. Similarly, extrapyramidal features, ophthalmoplegias and distal amyotrophy were seen in some but not in all families with SCA3 mutation. A peculiar form of abduction lag during slow pursuit movement of eyes was observed in an asymptomatic girl in an SCA3 family. CONCLUSIONS Although SCA2 has been claimed to be the commonest form of ADCA in India, this does not appear to be so in our ethnic Bengalee subjects. Phenotypic expression of the genotype also appears to be variable amongst families and individuals. Hence, phenotypic expression appears to be an inconsistent marker of the SCA genotype in our patients.
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Affiliation(s)
- A Chakravarty
- Division of Neurology, Vivekananda Institute of Medical Sciences, Calcutta, India.
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