Absence of spinocerebellar ataxia type 3/Machado-Joseph disease within ataxic patients in the Czech population
Language English Country Great Britain, England Media print
Document type Journal Article, Research Support, Non-U.S. Gov't
PubMed
16241973
DOI
10.1111/j.1468-1331.2005.01090.x
PII: ENE1090
Knihovny.cz E-resources
- MeSH
- Alleles MeSH
- Ataxin-3 MeSH
- Gene Frequency * MeSH
- Nuclear Proteins MeSH
- Humans MeSH
- Machado-Joseph Disease genetics MeSH
- Mutation MeSH
- DNA Mutational Analysis MeSH
- Polymorphism, Genetic * MeSH
- Nerve Tissue Proteins genetics MeSH
- Repressor Proteins MeSH
- Spinocerebellar Ataxias genetics MeSH
- Trinucleotide Repeats MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Geographicals
- Czech Republic MeSH
- Names of Substances
- Ataxin-3 MeSH
- ATXN3 protein, human MeSH Browser
- Nuclear Proteins MeSH
- Nerve Tissue Proteins MeSH
- Repressor Proteins MeSH
Although spinocerebellar ataxia type 3 (SCA3)/Machado-Joseph disease is the most common type of SCA worldwide, we did not identify any cases of the disease amongst SCA patients in the Czech population. It has been proposed that the prevalence of large normal alleles correlates with the frequency of various types of SCA. We have therefore attempted to resolve the absence of SCA3 in our population by investigating, within 204 normal chromosomes, the frequency and nature of CAG repeats as well as two intragenic polymorphisms. We found that large normal alleles with more than 33 CAG repeats were observed at a frequency of only 0.49%. Whereas most of the expanded alleles worldwide have the CA haplotype, this was the least common (5.4%) variant observed in our study, although it was associated with a larger mean CAG repeat length (26.9). We postulate that the absence of SCA3 in the Czech population might be explained by the lack of large normal alleles and consequently a relatively small reservoir for aberrant CAG expansions at the SCA3 locus.
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