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Shan Ouyang - One of the best experts on this subject based on the ideXlab platform.
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frequency of sca1 sca2 sca3 mjd sca6 sca7 and drpla cag trinucleotide repeat expansion in patients with hereditary spinocerebellar ataxia from chinese kindreds
JAMA Neurology, 2000Co-Authors: Beisha Tang, Lijuan Jing, Lu Shen, Shan OuyangAbstract:Objective To assess the frequency of SCA1 (spinocerebellar ataxia type 1), SCA2, SCA3/MJD (spinocerebellar ataxia type 3/Machado-Joseph disease), SCA6, SCA7, and DRPLA (Dentatorubropallidoluysian Atrophy) CAG trinucleotide repeat expansions [(CAG)n] among persons diagnosed with hereditary SCA from Chinese families. Patients and Methods Spinocerebellar ataxia type 1, SCA2, SCA3/MJD, SCA6, SCA7, and DRPLA (CAG)n mutation were detected with the polymerase chain reaction, highly denaturing polyacrylamide gel electrophoresis, and silver staining technique in 167 patients with autosomal dominant SCA from 85 Chinese families and 37 patients with sporadic SCA. Results Spinocerebellar ataxia type 1 (CAG)n mutation in 7 patients from 4 kindreds (4.70%) was expanded to 53 to 62 repeats. Spinocerebellar ataxia type 2 (CAG)n mutation in 12 patients from 5 kindreds (5.88%) was expanded to 42 to 47 repeats. Spinocerebellar ataxia type 3/Machado-Joseph disease (CAG)n mutation in 83 patients from 41 kindreds (48.23%) was expanded to 68 to 83 repeats. Sixty-five patients from 35 kindreds (41.19%) and 37 patients with sporadic SCA did not test positive for SCA1, SCA2, SCA3/MJD, SCA6, SCA7, or DRPLA. There was a predictable inverse relationship between the number of CAG repeats and the age at onset for SCA3/MJD and SCA2. Clinically, dementia and hyporeflexia were more frequent in patients with SCA2, while spasticity, hyperreflexia, and Babinski signs were more frequent in patients with SCA3/ MJD, and those might be helpful in clinical work to primarily distinguish patients with SCA3/MJD and SCA2 from others with different types of SCA. Conclusions The frequency of SCA3/MJD is substantially higher than that of SCA1 and SCA2 in patients with autosomal dominant SCA from Chinese kindreds, who are non-Portuguese. Clinical expressions of the various types of SCAs overlap one another; therefore, for clinical study it is important to make a gene diagnosis and genetic classification for patients with SCA.
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Frequency of SCA1, SCA2, SCA3/MJD, SCA6, SCA7, and DRPLA CAG trinucleotide repeat expansion in patients with hereditary spinocerebellar ataxia from Chinese kindreds.
Archives of neurology, 2000Co-Authors: Beisha Tang, Lijuan Jing, Lu Shen, Shan Ouyang, Chunyu Liu, Heping Dai, Qian Pan, Jiahui XiaAbstract:To assess the frequency of SCA1 (spinocerebellar ataxia type 1), SCA2, SCA3/MJD (spinocerebellar ataxia type 3/Machado-Joseph disease), SCA6, SCA7, and DRPLA (Dentatorubropallidoluysian Atrophy) CAG trinucleotide repeat expansions [(CAG)n] among persons diagnosed with hereditary SCA from Chinese families. Spinocerebellar ataxia type 1, SCA2, SCA3/MJD, SCA6, SCA7, and DRPLA (CAG)n mutation were detected with the polymerase chain reaction, highly denaturing polyacrylamide gel electrophoresis, and silver staining technique in 167 patients with autosomal dominant SCA from 85 Chinese families and 37 patients with sporadic SCA. Spinocerebellar ataxia type 1 (CAG)n mutation in 7 patients from 4 kindreds (4.70%) was expanded to 53 to 62 repeats. Spinocerebellar ataxia type 2 (CAG)n mutation in 12 patients from 5 kindreds (5.88%) was expanded to 42 to 47 repeats. Spinocerebellar ataxia type 3/Machado-Joseph disease (CAG)n mutation in 83 patients from 41 kindreds (48.23%) was expanded to 68 to 83 repeats. Sixty-five patients from 35 kindreds (41.19%) and 37 patients with sporadic SCA did not test positive for SCA1, SCA2, SCA3/MJD, SCA6, SCA7, or DRPLA. There was a predictable inverse relationship between the number of CAG repeats and the age at onset for SCA3/MJD and SCA2. Clinically, dementia and hyporeflexia were more frequent in patients with SCA2, while spasticity, hyperreflexia, and Babinski signs were more frequent in patients with SCA3/ MJD, and those might be helpful in clinical work to primarily distinguish patients with SCA3/MJD and SCA2 from others with different types of SCA. The frequency of SCA3/MJD is substantially higher than that of SCA1 and SCA2 in patients with autosomal dominant SCA from Chinese kindreds, who are non-Portuguese. Clinical expressions of the various types of SCAs overlap one another; therefore, for clinical study it is important to make a gene diagnosis and genetic classification for patients with SCA.
Beisha Tang - One of the best experts on this subject based on the ideXlab platform.
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frequency of sca1 sca2 sca3 mjd sca6 sca7 and drpla cag trinucleotide repeat expansion in patients with hereditary spinocerebellar ataxia from chinese kindreds
JAMA Neurology, 2000Co-Authors: Beisha Tang, Lijuan Jing, Lu Shen, Shan OuyangAbstract:Objective To assess the frequency of SCA1 (spinocerebellar ataxia type 1), SCA2, SCA3/MJD (spinocerebellar ataxia type 3/Machado-Joseph disease), SCA6, SCA7, and DRPLA (Dentatorubropallidoluysian Atrophy) CAG trinucleotide repeat expansions [(CAG)n] among persons diagnosed with hereditary SCA from Chinese families. Patients and Methods Spinocerebellar ataxia type 1, SCA2, SCA3/MJD, SCA6, SCA7, and DRPLA (CAG)n mutation were detected with the polymerase chain reaction, highly denaturing polyacrylamide gel electrophoresis, and silver staining technique in 167 patients with autosomal dominant SCA from 85 Chinese families and 37 patients with sporadic SCA. Results Spinocerebellar ataxia type 1 (CAG)n mutation in 7 patients from 4 kindreds (4.70%) was expanded to 53 to 62 repeats. Spinocerebellar ataxia type 2 (CAG)n mutation in 12 patients from 5 kindreds (5.88%) was expanded to 42 to 47 repeats. Spinocerebellar ataxia type 3/Machado-Joseph disease (CAG)n mutation in 83 patients from 41 kindreds (48.23%) was expanded to 68 to 83 repeats. Sixty-five patients from 35 kindreds (41.19%) and 37 patients with sporadic SCA did not test positive for SCA1, SCA2, SCA3/MJD, SCA6, SCA7, or DRPLA. There was a predictable inverse relationship between the number of CAG repeats and the age at onset for SCA3/MJD and SCA2. Clinically, dementia and hyporeflexia were more frequent in patients with SCA2, while spasticity, hyperreflexia, and Babinski signs were more frequent in patients with SCA3/ MJD, and those might be helpful in clinical work to primarily distinguish patients with SCA3/MJD and SCA2 from others with different types of SCA. Conclusions The frequency of SCA3/MJD is substantially higher than that of SCA1 and SCA2 in patients with autosomal dominant SCA from Chinese kindreds, who are non-Portuguese. Clinical expressions of the various types of SCAs overlap one another; therefore, for clinical study it is important to make a gene diagnosis and genetic classification for patients with SCA.
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Frequency of SCA1, SCA2, SCA3/MJD, SCA6, SCA7, and DRPLA CAG trinucleotide repeat expansion in patients with hereditary spinocerebellar ataxia from Chinese kindreds.
Archives of neurology, 2000Co-Authors: Beisha Tang, Lijuan Jing, Lu Shen, Shan Ouyang, Chunyu Liu, Heping Dai, Qian Pan, Jiahui XiaAbstract:To assess the frequency of SCA1 (spinocerebellar ataxia type 1), SCA2, SCA3/MJD (spinocerebellar ataxia type 3/Machado-Joseph disease), SCA6, SCA7, and DRPLA (Dentatorubropallidoluysian Atrophy) CAG trinucleotide repeat expansions [(CAG)n] among persons diagnosed with hereditary SCA from Chinese families. Spinocerebellar ataxia type 1, SCA2, SCA3/MJD, SCA6, SCA7, and DRPLA (CAG)n mutation were detected with the polymerase chain reaction, highly denaturing polyacrylamide gel electrophoresis, and silver staining technique in 167 patients with autosomal dominant SCA from 85 Chinese families and 37 patients with sporadic SCA. Spinocerebellar ataxia type 1 (CAG)n mutation in 7 patients from 4 kindreds (4.70%) was expanded to 53 to 62 repeats. Spinocerebellar ataxia type 2 (CAG)n mutation in 12 patients from 5 kindreds (5.88%) was expanded to 42 to 47 repeats. Spinocerebellar ataxia type 3/Machado-Joseph disease (CAG)n mutation in 83 patients from 41 kindreds (48.23%) was expanded to 68 to 83 repeats. Sixty-five patients from 35 kindreds (41.19%) and 37 patients with sporadic SCA did not test positive for SCA1, SCA2, SCA3/MJD, SCA6, SCA7, or DRPLA. There was a predictable inverse relationship between the number of CAG repeats and the age at onset for SCA3/MJD and SCA2. Clinically, dementia and hyporeflexia were more frequent in patients with SCA2, while spasticity, hyperreflexia, and Babinski signs were more frequent in patients with SCA3/ MJD, and those might be helpful in clinical work to primarily distinguish patients with SCA3/MJD and SCA2 from others with different types of SCA. The frequency of SCA3/MJD is substantially higher than that of SCA1 and SCA2 in patients with autosomal dominant SCA from Chinese kindreds, who are non-Portuguese. Clinical expressions of the various types of SCAs overlap one another; therefore, for clinical study it is important to make a gene diagnosis and genetic classification for patients with SCA.
Yasuto Itoyama - One of the best experts on this subject based on the ideXlab platform.
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Reduction of CAG expansions in cerebellar cortex and spinal cord of DRPLA.
Clinical genetics, 2008Co-Authors: Masashi Aoki, Koji Abe, T. Kameya, M. Watanabe, M. Tobita, Yasuto ItoyamaAbstract:Recent studies have identified an unstable expansion of a CAG repeat in a gene located on chromosome 12 as a cause of Dentatorubropallidoluysian Atrophy (DRPLA). To investigate whether the somatic heterogeneity may relate to the selective neuronal damage caused by the disease, genomic DNA from various tissues of an autopsied patient with DRPLA was examined to compare possible variations of expanded CAG repeats for the disease. Although the size of the expanded CAG repeat from many organs was almost the same as that from peripheral lymphocytes, those from cerebellar cortex and spinal cord were unexpectedly reduced and numbers of peaks within an expanded allele were relatively strict. These results suggest that the CAG repeat is not simply expanded in the genome of the tissues that are most involved in DRPLA, but that another mechanism might be responsible for the specific neuronal death.
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High prevalence of spinocerebellar ataxia type 1 (SCA1) in an isolated region of Japan
Journal of the neurological sciences, 2000Co-Authors: Yoshiaki Onodera, Masashi Aoki, Koji Abe, Tetsuya Nagata, T. Kameya, T. Tsuda, Hiroyuki Kato, Yasuto ItoyamaAbstract:Autosomal dominant cerebeller ataxias (ADCAs) are a heterogeneous group of neurodegenerative disorders that differ in both the clinical manifestations and modes of inheritance. At present, eight different genes causing ADCAs have been found: spinocerebeller ataxia type 1 (SCA1), SCA2, SCA3/Machado-Joseph disease (MJD), SCA6, SCA7, SCA8, SCA12 and Dentatorubropallidoluysian Atrophy (DRPLA). The relative prevalence of each mutation varies according to race and native place. We studied 117 unrelated ADCA families that originated from the Tohoku District in the northernmost part of Honshu Island in Japan (mainly Miyagi Prefecture in the central part of Tohoku District). The SCA1 mutation was the most frequent among the known disorders (24.8% of all such families). The relative prevalence of SCA1 in the Tohoku District is very high compared with the values already reported from other regions in the world. Because the population of this area had seldom moved, the alleles with SCA1 mutations (including alleles with an intermediate CAG repeat number) are assumed to have been present in this area for a long time.
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Analysis of spinocerebellar ataxia type 2 in Gunma Prefecture in Japan: CAG trinucleotide expansion and clinical characteristics
Journal of the neurological sciences, 1998Co-Authors: Kazuyuki Mizushima, Masashi Aoki, Koji Abe, Yasuto Itoyama, Mitsunori Watanabe, Masami Shizuka, Koichi Okamoto, Mikio ShojiAbstract:We analyzed 13 patients with spinocerebellar ataxia type 2 (SCA2) in seven unrelated families who live in Gunma Prefecture, Japan (population approx. 2 000 000), and documented the clinical and molecular properties correlated with the CAG repeat expansion. Twelve of the 13 patients and one presymptomatic female were genetically examined, and the CAG repeat number of the expanded and normal alleles was 40.8±4.8 (mean±S.D., n=13) and 22±0 (n=13), respectively. The repeat size of the expanded alleles was inversely correlated with the patients' age at onset. Paternal anticipation was observed, accompanied by an increase of the CAG repeat size. The patients presented here were clinically characterized by a relatively higher frequency of slow saccades, hyporeflexia, hypotonia, and tremor. A number of peaks in the expanded allele on polyacrylamide gel electrophoresis showed the presence of cell mosaicism in SCA2 as well. In Gunma Prefecture, SCA2, Machado-Joseph disease and spinocerebellar ataxia type 6 are almost equally present and at higher frequencies than spinocerebellar ataxia type 1 and hereditary Dentatorubropallidoluysian Atrophy, which are rare. Thus, the difference of frequency of autosomal dominant spinocerebellar ataxias may be present in Japan.
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A Japanese family with Machado-Joseph disease characterized by initial emaciation and myoclonus.
European Journal of Neurology, 1995Co-Authors: Masashi Aoki, Koji Abe, Tetsuya Nagata, T. Kameya, M. Watanabe, Hiroshi Onodera, Hiroshi Mochizuki, Yasuto ItoyamaAbstract:We describe a Japanese family with hereditary spinocerebellar ataxia characterized by initial emaciation and myoclonus. The proband first noted truncal ataxia, myoclonus in the shoulder and general emaciation at age 24. The other affected members of the family also had such emaciation in the early stage of the disease. The DNA analyses of the family revealed that the patients of the family are associated with the expansions of CAG repeats for Machado-Joseph disease (MJD) on the long arm of chromosome 14. Although the clinical features of MJD are very variable, general emaciation in an early stage of the disease and systemic myoclonus have not been documented. Because it is sometimes difficult to distinguish among hereditary spinocerebellar ataxias such as spinocerebellar ataxia type 1 (SCA1) or Dentatorubropallidoluysian Atrophy (DRPLA) by clinical features, a genetic examination provides better understanding of such a rare and ambiguous type of hereditary spinocerebellar ataxia.
Isabel Silveira - One of the best experts on this subject based on the ideXlab platform.
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Portuguese families with Dentatorubropallidoluysian Atrophy (DRPLA) share a common haplotype of Asian origin
European Journal of Human Genetics, 2003Co-Authors: Sandra Martins, Teresa Matamá, Laura Guimarães, José Vale, João Guimarães, Lina Ramos, Paula Coutinho, Jorge Sequeiros, Isabel SilveiraAbstract:Dentatorubropallidoluysian Atrophy (DRPLA) is an autosomal dominant neurodegenerative disorder characterized by a variable combination of progressive ataxia, epilepsy, myoclonus, choreoathetosis and dementia. This disease is caused by a (CAG)_ n expansion in the DRPLA gene, on chromosome 12p13. DRPLA is prevalent in Japan, but several families of non-Japanese ancestry have already been published. To identify the origin of expanded alleles in Portuguese families with DRPLA, we studied two previously reported intragenic SNPs in introns 1 and 3, in addition to the CAG repeat of the DRPLA gene. The results showed that all four Portuguese DRPLA families shared the same haplotype, which is also common to that reported for Japanese DRPLA chromosomes. This haplotype is also the most frequent in Japanese normal alleles, whereas it was rare in Portuguese control chromosomes. Thus, our findings support that a founder DRPLA haplotype of Asian origin was introduced in Portugal, being responsible for the frequency of the disease in this country.
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Trinucleotide Repeats in 202 Families With Ataxia: A Small Expanded (CAG)n Allele at the SCA17 Locus
Archives of neurology, 2002Co-Authors: Isabel Silveira, Laura Guimarães, Carlos Miranda, M-c Moreira, Isabel Alonso, P. Mendonça, Anabela Ferro, Jorge Pinto-basto, Joel Coelho, Fátima FerreirinhaAbstract:nantly transmitted cases had (CAG)n expansions at the Machado-Joseph disease gene (MJD1) (63%), at SCA2 (3%), the gene for Dentatorubropallidoluysian Atrophy (DRPLA) (2%), SCA6 (1%), or SCA7 (1%) loci, or (CTG)n expansions at the SCA8 (2%) gene, whereas (GAA)n expansions in the Freidreich ataxia gene (FRDA) were found in 64% of families with recessive ataxia. Isolated patients also had TNR expansions at the MJD1 (6%), SCA8 (6%), or FRDA (8%) genes; in addition, an expanded allele at the TATA-binding protein gene (TBP), with 43 CAGs, was present in a patient with ataxia and mental deterioration. Associations between frequencies of SCA2 and SCA6 and a frequency of large normal alleles were found in Portuguese and Brazilian individuals, respectively. Interestingly, no association between the frequencies of DRPLA and large normal alleles was found in the Portuguese group. Conclusions: Our results show that (1) a significant number of isolated cases of ataxia are due to TNR expansions; (2) expanded DRPLA alleles in Portuguese families may have evolved from an ancestral haplotype; and (3) small (CAG)n expansions at the TBP gene may cause SCA17. Arch Neurol. 2002;59:623-629
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Analysis of SCA1, DRPLA, MJD, SCA2, and SCA6 CAG repeats in 48 portuguese ataxia families
American journal of medical genetics, 1998Co-Authors: Isabel Silveira, Paula Coutinho, Jorge Sequeiros, Patrícia Maciel, Claudia Gaspar, S. Hayes, Ana I. Dias, João Tiago Guimarães, Leal Loureiro, Guy A. RouleauAbstract:The spinocerebellar ataxias (SCAs) are clinically and genetically a heterogeneous group of neurodegenerative disorders. To date, eight different loci causing SCA have been identified: SCA1, SCA2, Machado-Joseph disease (MJD)/SCA3, SCA4, SCA5, SCA6, SCA7, and Dentatorubropallidoluysian Atrophy (DRPLA). Expansion of a CAG repeat in the disease genes has been found in five of these disorders. To estimate the relative frequencies of the SCA1, DRPLA, MJD, SCA2, and SCA6 mutations among Portuguese ataxia patients, we collected DNA samples from 48 ataxia families and performed polymerase chain reaction (PCR) amplification of the CAG repeat mutations on chromosomes 6p, 12p, 14q, 12q, and 19p, respectively. Fifty-five individuals belonging to 34 dominant families (74%) had an expanded CAG repeat at the MJD gene. In five individuals from two kindreds with a dominant pattern of inheritance (4%), an expanded CAG repeat at the SCA2 gene was found. In MJD patients, the normal allele size ranged from 13 to 41, whereas the mutant alleles contained 65 to 80 repeats. For the SCA2 patients, normal alleles had 22 or 23, while expanded alleles had between 36 and 47 CAG units. We did not find the SCA1, DRPLA, or SCA6 mutations in our group of families. The MJD mutation remains the most common cause of SCA in Portugal, while a small number of cases are caused by mutations at the SCA2 gene, and 22% are due to still unidentified genes.
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Frequency of spinocerebellar ataxia type 1, Dentatorubropallidoluysian Atrophy, and Machado-Joseph disease mutations in a large group of spinocerebellar ataxia patients
Neurology, 1996Co-Authors: Isabel Silveira, Paula Coutinho, Mi Botez, Iscia Lopes-cendes, Stephen J. Kish, Patrícia Maciel, Claudia Gaspar, Helio Ghizoni Teive, Walter Oleschko Arruda, Carlos Eduardo SteinerAbstract:Article abstract-The spinocerebellar ataxias (SCAs) are a heterogeneous group of neurodegenerative disorders varying in both clinical manifestations and mode of inheritance. Six different genes causing autosomal dominant SCA are mapped: SCA1, SCA2, Machado-Joseph disease (MJD)/SCA3, SCA4, SCA5, and Dentatorubropallidoluysian Atrophy (DRPLA). Expansions of an unstable trinucleotide CAG repeat cause three of these disorders: SCA type 1 (SCA1), MJD, and DRPLA. We determined the frequency of the SCA1, DRPLA, and MJD mutations in a large group of unrelated SCA patients with various patterns of inheritance and different ethnic backgrounds. We studied 92 unrelated SCA patients. The frequency of the SCA1 mutation was 3% in the overall patient group and 10% in the non-Portuguese dominantly inherited SCA subgroup. We found the DRPLA mutation in only one Japanese patient, who was previously diagnosed with this disease. We identified the MJD mutation in 41% of the overall patient group, which included 38 autosomal dominant kindreds of Portuguese origin; the frequency of the MJD mutation among the non-Portuguese dominantly inherited cases was 17%. These results suggest that SCA may be occasionally caused by the SCA1 mutation and rarely caused by the DRPLA mutation and that, to date, the MJD mutation seems to be the most common cause of dominantly inherited SCA. Finally, our results suggest that recessively inherited cases of SCA are not caused by the known trinucleotide repeat expansions. NEUROLOGY 1996;46: 214-218
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Clinical and molecular characteristics of a Brazilian family with spinocerebellar ataxia type 1
Arquivos de neuro-psiquiatria, 1996Co-Authors: Iscia Lopes-cendes, Isabel Silveira, Carlos Eduardo Steiner, Walter Pinto-junior, Jayme Antunes Maciel, Guy A. RouleauAbstract:The spinocerebellar ataxias (SCAs) are a clinically and genetically heterogeneous group of late onset neurodegenerative disorders. To date, seven different genes causing autosomal dominant SCA have been mapped: SCA1, SCA2, Machado-Joseph disease (MJD)/SCA3, SCA4, SCA5, SCA7 and Dentatorubropallidoluysian Atrophy (DRPLA). Expansions of an unstable trinucleotide CAG repeat cause three of these disorders: SCA1, MJD/SCA3 and DRPLA. We studied one Brazilian family segregating an autosomal dominant type of SCA. A total of ten individuals were examined and tested for the presence of the SCA1, MJD and DRPLA mutations. Three individuals, one male and two females, were considered affected based on neurological examination; ages at onset were: 32, 36 and 41 years. The first complaint in all three patients was gait ataxia which progressed slowly over the years. Six individuals showed one allele containing an expanded CAG repeat in the SCA1 gene. The mean size of the expanded allele was 48.2 CAG units. Instability of the expanded CAG tract was seen in the two transmissions that were observed in this family. In both occasions there was a contraction of the CAG tract. Our study demonstrates that SCA1 occurs in the Brazilian population. In addition, our results stress the importance of molecular studies in the confirmation of diagnosis and for pre-symptomatic testing in SCAs.
Jiahui Xia - One of the best experts on this subject based on the ideXlab platform.
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Frequency of SCA1, SCA2, SCA3/MJD, SCA6, SCA7, and DRPLA CAG trinucleotide repeat expansion in patients with hereditary spinocerebellar ataxia from Chinese kindreds.
Archives of neurology, 2000Co-Authors: Beisha Tang, Lijuan Jing, Lu Shen, Shan Ouyang, Chunyu Liu, Heping Dai, Qian Pan, Jiahui XiaAbstract:To assess the frequency of SCA1 (spinocerebellar ataxia type 1), SCA2, SCA3/MJD (spinocerebellar ataxia type 3/Machado-Joseph disease), SCA6, SCA7, and DRPLA (Dentatorubropallidoluysian Atrophy) CAG trinucleotide repeat expansions [(CAG)n] among persons diagnosed with hereditary SCA from Chinese families. Spinocerebellar ataxia type 1, SCA2, SCA3/MJD, SCA6, SCA7, and DRPLA (CAG)n mutation were detected with the polymerase chain reaction, highly denaturing polyacrylamide gel electrophoresis, and silver staining technique in 167 patients with autosomal dominant SCA from 85 Chinese families and 37 patients with sporadic SCA. Spinocerebellar ataxia type 1 (CAG)n mutation in 7 patients from 4 kindreds (4.70%) was expanded to 53 to 62 repeats. Spinocerebellar ataxia type 2 (CAG)n mutation in 12 patients from 5 kindreds (5.88%) was expanded to 42 to 47 repeats. Spinocerebellar ataxia type 3/Machado-Joseph disease (CAG)n mutation in 83 patients from 41 kindreds (48.23%) was expanded to 68 to 83 repeats. Sixty-five patients from 35 kindreds (41.19%) and 37 patients with sporadic SCA did not test positive for SCA1, SCA2, SCA3/MJD, SCA6, SCA7, or DRPLA. There was a predictable inverse relationship between the number of CAG repeats and the age at onset for SCA3/MJD and SCA2. Clinically, dementia and hyporeflexia were more frequent in patients with SCA2, while spasticity, hyperreflexia, and Babinski signs were more frequent in patients with SCA3/ MJD, and those might be helpful in clinical work to primarily distinguish patients with SCA3/MJD and SCA2 from others with different types of SCA. The frequency of SCA3/MJD is substantially higher than that of SCA1 and SCA2 in patients with autosomal dominant SCA from Chinese kindreds, who are non-Portuguese. Clinical expressions of the various types of SCAs overlap one another; therefore, for clinical study it is important to make a gene diagnosis and genetic classification for patients with SCA.