Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Article
  • Published:

An untranslated CTG expansion causes a novel form of spinocerebellar ataxia (SCA8)

Abstract

Myotonic dystrophy (DM) is the only disease reported to be caused by a CTG expansion. We now report that a non-coding CTG expansion causes a novel form of spinocerebellar ataxia (SCA8). This expansion, located on chromosome 13q21, was isolated directly from the genomic DNA of an ataxia patient by RAPID cloning. SCA8 patients have expansions similar in size (107-127 CTG repeats) to those found among adult-onset DM patients. SCA8 is the first example of a dominant SCA not caused by a CAG expansion translated as a polyglutamine tract.

This is a preview of subscription content, access via your institution

Access options

Buy this article

Prices may be subject to local taxes which are calculated during checkout

Figure 1: RAPID cloning of the SCA8 expanded CTG repeat.
Figure 2: Large SCA8 kindred.
Figure 3: PCR analysis of SCA8 CTG affected and normal alleles.
Figure 4: Intergenerational variation in repeat number for maternal and paternal transmissions.
Figure 5: The SCA8 repeat is transcribed exclusively in the CTG orientation and is present in the 3´ terminal exon of a fully processed transcript.

Similar content being viewed by others

Accession codes

Accessions

GenBank/EMBL/DDBJ

References

  1. Subramony, S.H. & Currier, R.D. The classification of familial ataxias. in Handbook of Clinical Neurology (eds Vinken, P.J., Bruyn, G.W. & Klawans, H.L.) 271–284 (Elsevier Science Publishing Company, New York, 1991).

    Google Scholar 

  2. Harding, A.E. The clinical features and classification of the late onset autosomal dominant cerebellar ataxia: a study of 11 families, including descendants of 'The Drew Family of Walworth'. Brain 105, 1–28 (1982).

    Article  CAS  PubMed  Google Scholar 

  3. Zoghbi, H.Y. The spinocerebellar degenerations. Curr. Neurol. 11, 121–144 (1991).

    Google Scholar 

  4. Brice, A. Unstable mutations and neurodegenerative disorders. J. Neurol. 245, 505–510 (1998).

    Article  CAS  PubMed  Google Scholar 

  5. Klockgether, T. & Evert, B. Genes involved in hereditary ataxias. Trends Neurosci. 21, 413–418 (1998).

    Article  CAS  PubMed  Google Scholar 

  6. Jansen, G. et al. Abnormal myotonic dystrophy protein kinase levels produce only mild myopathy in mice. Nature Genet. 13, 316–324 (1996).

    Article  CAS  PubMed  Google Scholar 

  7. Reddy, S. et al. Mice lacking the myotonic dystrophy protein kinase develop a late onset progressive myopathy. Nature Genet. 13, 325–335 (1996).

    Article  CAS  PubMed  Google Scholar 

  8. Groenen, P. & Wieringa, B. Expanding complexity in myotonic dystrophy. Bioessays 20, 901–912 (1998).

    Article  CAS  PubMed  Google Scholar 

  9. Hoffmann-Radvanyi, H. et al. Myotonic dystrophy: absence of CTG enlarged transcript in congenital forms, and low expression of the normal allele. Hum. Mol. Genet. 2, 1263–1266 (1993).

    Article  Google Scholar 

  10. Krahe, R. et al. Effect of myotonic dystrophy trinucleotide repeat expansion on DMPK transcription and processing. Genomics 28, 1–14 (1995).

    Article  CAS  PubMed  Google Scholar 

  11. Taneja, K.L., McCurrach, M., Schalling, M., Housman, D. & Singer, R.H. Foci of trinucleotide repeat transcripts in nuclei of myotonic dystrophy cells and tissues. J. Cell Biol. 128, 995–1002 (1995).

    Article  CAS  PubMed  Google Scholar 

  12. Davis, B.M., McCurrach, M.E., Taneja, K.L., Singer, R.H. & Housman, D.E. Expansion of a CUG trinucleotide repeat in the 3´ untranslated region of myotonic dystrophy protein kinase transcripts results in nuclear retention of transcripts. Proc. Natl Acad. Sci. USA 94, 7388–7393 (1997).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  13. Timchenko, L.T. et al. Identification of a (CUG)n triplet repeat RNA-binding protein and its expression in myotonic dystrophy. Nucleic Acids Res. 24, 4407–4414 (1996).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  14. Roberts, R. et al. Altered phosphorylation and intracellular distribution of a (CUG)n triplet repeat RNA-binding protein in patients with myotonic dystrophy and in myotonin protein kinase knockout mice. Proc. Natl Acad. Sci. USA 94, 13221–13226 (1997).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  15. Philips, A.V., Timchenko, L.T. & Cooper, T.A. Disruption of splicing regulated by a CUG-binding protein in myotonic dystrophy. Science 280, 737–741 (1998).

    Article  CAS  PubMed  Google Scholar 

  16. Schalling, M., Hudson, T., Buetow, K. & Housman, D. Direct detection of novel expanded trinucleotide repeats in the human genome. Nature Genet. 4, 135–139 (1993).

    Article  CAS  PubMed  Google Scholar 

  17. Koob, M.D. et al. Rapid cloning of expanded trinucleotide repeat sequences from genomic DNA. Nature Genet. 18, 72–75 (1998).

    Article  CAS  PubMed  Google Scholar 

  18. Moseley, M.L. et al. Incidence of dominant spinocerebellar and Friedreich triplet repeats among 361 ataxia families. Neurology 51, 1666–1671 (1998).

    Article  CAS  PubMed  Google Scholar 

  19. Chung, M.-y. et al. Evidence for a mechanism predisposing to intergenerational CAG repeat instability in spinocerebellar ataxia type 1. Nature Genet. 5, 254–258 (1993).

    Article  CAS  PubMed  Google Scholar 

  20. Cancel, G. et al. Molecular and clinical correlations in spinocerebellar ataxia 2×a study of 32 families. Hum. Mol. Genet. 6, 709–715 (1997).

    Article  CAS  PubMed  Google Scholar 

  21. Maruyama, H. et al. Molecular features of the CAG repeats and clinical manifestation of Machado-Joseph disease. Hum. Mol. Genet. 4, 807–812 (1995).

    Article  CAS  PubMed  Google Scholar 

  22. Maciel, P. et al. Correlation between CAG repeat length and clinical features in Machado-Joseph disease. Am. J. Hum. Genet. 57, 54–61 (1995).

    CAS  PubMed  PubMed Central  Google Scholar 

  23. Zhuchenko, O. et al. Autosomal dominant cerebellar ataxia (SCA6) associated with small polyglutamine expansions in the ×-1A-voltage-dependent calcium channel. Nature Genet. 15, 62–69 (1997).

    Article  CAS  PubMed  Google Scholar 

  24. Jodice, C. et al. Episodic ataxia type 2 (EA2) and spinocerebellar atxia type 6 (SCA6) due to CAG repeat expansion in the CACNA1A gene on chromosome 19p. Hum. Mol. Genet. 6, 1973–1978 (1997).

    Article  CAS  PubMed  Google Scholar 

  25. David, G. et al. Molecular and clinical correlations in autosomal dominant cerebellar ataxia with progressive macular dystrophy (SCA7). Hum. Mol. Genet. 7, 165–170 (1998).

    Article  CAS  PubMed  Google Scholar 

  26. Tsilfidis, C., MacKenzie, A.E., Mettler, G., Barcelo, J. & Korneluk, R.G. Correlation between CTG trinucleotide repeat length and frequency of severe congenital myotonic dystrophy. Nature Genet. 1, 192–195 (1992).

    Article  CAS  PubMed  Google Scholar 

  27. Vanhee-Brossollet, C. & Vaquero, C. Do natural antisense transcripts make sense in eukaryotes? Gene 211, 1–9 (1998).

    Article  CAS  PubMed  Google Scholar 

  28. Nellen, W. & Lichtenstein, C. What makes an mRNA anti-sense-itive? Trends Biochem. Sci. 18, 419–423 (1993).

    Article  CAS  PubMed  Google Scholar 

  29. Lathrop, G.M., Lalouel, J.M., Julier, C. & Ott, J. Strategies for multilocus linkage analysis in humans. Proc. Natl Acad. Sci. USA 81, 3443–3446 (1984).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

Download references

Acknowledgements

We thank family members for their participation, C. Peterson, H. Lipe and D. Nochlin for help developing the pedigrees and H. Orr for critically reading the manuscript. This work was supported by grants from the National Ataxia Foundation, the Bob Allison Ataxia Research Center, VA research funds and the National Institutes of Health (P01 NS33718 and RO1 NS36282).

Author information

Authors and Affiliations

Authors

Corresponding authors

Correspondence to Michael D. Koob or Laura P.W. Ranum.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Koob, M., Moseley, M., Schut, L. et al. An untranslated CTG expansion causes a novel form of spinocerebellar ataxia (SCA8). Nat Genet 21, 379–384 (1999). https://doi.org/10.1038/7710

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1038/7710

This article is cited by

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing