A study of the CCG polymorphism in the IT15 cDNA in the Scottish Huntington`s disease and normal populations
- Univ. of Edinburgh (United Kingdom); and others
The CCG rich sequence immediately 3{prime} to the CAG repeat that is expanded in Huntington`s disease (HD) has recently been shown to be polymorphic with at least 5 alleles differing by multiples of 3 bp being found in the normal population. We have studied the allele distribution in 200 Scottish HD families and have found very strong evidence for almost complete disequilibrium in this population. For all the families phase was unambiguously determined and 196 were shown to have a CCG repeat allele of 176 bp cosegregating with the HD chromosome. This observation is significantly different to the normal population distribution where 31% of people have an allele of 185 bp. This overrepresentation of the 176 bp allele is also seen in the normal population on chromosomes with greater than 26 CAG repeats. The DNA sequence across the CAG and CCG repeats has been obtained for the four HD patients that do not have a 176 bp CCG repeat size and will be presented. We present strong evidence of genetic heterogeneity in the Scottish HD population making it very unlikely that there is a founder effect in the Scottish HD population. These data suggest that we may have identified a region of the IT15 gene that is critical in the mechanism of Huntington`s disease CAG expansion.
- OSTI ID:
- 134160
- Report Number(s):
- CONF-941009--
- Journal Information:
- American Journal of Human Genetics, Journal Name: American Journal of Human Genetics Journal Issue: Suppl.3 Vol. 55; ISSN AJHGAG; ISSN 0002-9297
- Country of Publication:
- United States
- Language:
- English
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