Human Genetics

, Volume 98, Issue 6, pp 643–645

Relationship of (CAG)nC configuration to repeat instability of the Machado-Joseph disease gene

  • R. Matsumura
  • Tetsuya Takayanagi
  • Kayoko Murata
  • Naonobu Futamura
  • Makito Hirano
  • Satoshi Ueno
Original investigation

DOI: 10.1007/s004390050276

Cite this article as:
Matsumura, R., Takayanagi, T., Murata, K. et al. Hum Genet (1996) 98: 643. doi:10.1007/s004390050276

Abstract

The mutation responsible for Machado-Joseph disease (MJD) has been identified as an expansion of a CAG trinucleotide repeat in a novel gene on chromosome 14q32.1. The CAG repeat tract is followed by C or G, and alleles are thereby divided into two types on the basis of molecular configuration, (CAG)nC and (CAG)nG. We have studied the relationship between the repeat length and the configuration in 38 patients from 28 Japanese families with MJD, and 31 unrelated normal Japanese subjects. The CAG repeat length in 100 normal alleles ranged from 13 to 37 repeats, while 38 MJD patients had one expanded allele with 64 to 84 repeats. Surprisingly, the expanded alleles had exclusively the (CAG)nC configuration, while both (CAG)nC and (CAG)nG were seen in normal alleles from MJD and control subjects. Furthermore, in normal alleles, the CAG repeat tract was significantly longer in (CAG)nC than in (CAG)nG. These findings suggest that the (CAG)nC configuration is related to repeat instability of the MJD gene.

Copyright information

© Springer-Verlag Berlin Heidelberg 1996

Authors and Affiliations

  • R. Matsumura
    • 1
  • Tetsuya Takayanagi
    • 1
  • Kayoko Murata
    • 1
  • Naonobu Futamura
    • 1
  • Makito Hirano
    • 2
  • Satoshi Ueno
    • 2
  1. 1.Department of Neurology, Nara Medical University, 840 Shijocho, Kashihara, Nara 634, Japan Tel.: +81-7442-2-3051 ext. 3417; Fax: +81-7442-4-6065JP
  2. 2.Department of Medical Genetics, Nara Medical University, 840 Shijocho, Kashihara, Nara, JapanJP