The repeat expansion detection method in the analysis of diseases with CAG/CTG repeat expansion: Usefulness and limitations

Lourdes Martorell, Miguel Angel Pujana, Victor Volpini, Aurora Sanchez, Jorge Joven, Elisabet Vilella, Xavier P. Estivill

Research output: Contribution to journalArticle

9 Citations (Scopus)


The repeat expansion detection (RED) method was described to detect expansions of trinucleotide repeats of unknown chromosomal location. We have improved the RED method by the use of 8-mer oligonucleotides and assessed its usefulness in 30 samples from patients with spinocerebellar ataxia type 1 (SCA1), Huntington's disease (HD), and Machado Joseph's disease (MJD), for which the number of CAG/CTG repeats was determined by sequencing. There was a good correlation between the number of repeats detected by sequencing and those identified by RED. However, in 17% of samples, the RED gave additional fragments for ligation products of different size than the CAG/CTG repeat expansion detected in the sample by sequencing. The same was observed in a group of control subjects (n = 78) without known clinical abnormalities in which products of more than 40 repeats were detected in 27% of them, indicating that CAG/CTG repeat expansions are common in the general population. Wether this corresponds to unidentified loci with expansions deserves further investigation.

Original languageEnglish
Pages (from-to)486-488
Number of pages3
JournalHuman Mutation
Issue number6
Publication statusPublished - 1997
Externally publishedYes



  • Huntington's disease
  • Machado Joseph's disease
  • Repeat expansion detection
  • Spinocerebellar ataxia type 1

ASJC Scopus subject areas

  • Genetics
  • Genetics(clinical)

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