A novel long and unstable CAG/CTG trinucleotide repeat on chromosome 17q

Takeshi Ikeuchi, Kazuhiro Sanpei, Hiroki Takano, Hidenao Sasaki, Kunio Tashiro, Géraldine Cancel, Alexis Brice, Thomas D. Bird, Gerry D. Schellenberg, Margaret A. Pericak-Vance, Kathleen A. Welsh-Bohmer, Lorraine N. Clark, Kirk Wilhelmsen, Shoji Tsuji

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39 Scopus citations


Using the direct identification of repeat expansion and cloning technique, we cloned a novel long CAG/CTG trinucleotide repeat on chromosome 17. Using radiation hybrid panels, the CAG/CTG repeat was mapped to chromosome 17q. The CAG/CTG repeat is highly polymorphic, with a heterozygosity of 85%, and exhibits a bimodal distribution (allele S, 10-26 repeat units, and allele L, 50-92 repeat units). The CAG/CTG repeat of allele L exhibited intergenerational instabilities, which are more prominent in maternal transmission than in paternal transmission. Analyses of Northern blot and RT-PCR indicate that the repeat is transcribed. Although the size of the CAG/CTG repeat of allele L is within the range of the expanded CAG repeat of disease-causing genes, we did not detect any association of allele L with various neurodegenerative diseases, including frontotemporal dementia and parkinsonism, mapped to 17q21-q23.

Original languageEnglish (US)
Pages (from-to)321-326
Number of pages6
Issue number2
StatePublished - Apr 15 1998


ASJC Scopus subject areas

  • Genetics

Cite this

Ikeuchi, T., Sanpei, K., Takano, H., Sasaki, H., Tashiro, K., Cancel, G., Brice, A., Bird, T. D., Schellenberg, G. D., Pericak-Vance, M. A., Welsh-Bohmer, K. A., Clark, L. N., Wilhelmsen, K., & Tsuji, S. (1998). A novel long and unstable CAG/CTG trinucleotide repeat on chromosome 17q. Genomics, 49(2), 321-326. https://doi.org/10.1006/geno.1998.5266