Direct detection of novel expanded trinucleotide repeats in the human genome

Nat Genet. 1993 Jun;4(2):135-9. doi: 10.1038/ng0693-135.


Expansion of trinucleotide repeats can give rise to genetic disease. We have developed a technique, repeat expansion detection (RED), that can identify potentially pathological repeat expansion without prior knowledge of chromosomal location. Human genomic DNA is used as a template for a two-step cycling process that generates oligonucleotide multimers when expanded trinucleotide sequences are present at the level found in myotonic dystrophy and fragile-X patients. We have identified at least one new locus exhibiting trinucleotide expansion. Analysis of three families transmitting a long CTG repeat shows that the allele in these families corresponds to a locus on chromosome 18. RED constitutes a powerful tool to identify other diseases caused by this mechanism, particularly diseases associated with anticipation.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Chromosomes, Human, Pair 18*
  • DNA Ligases
  • DNA Mutational Analysis / methods*
  • Fragile X Syndrome / genetics
  • Gene Amplification*
  • Genetic Testing
  • Genome, Human*
  • Humans
  • Lod Score
  • Myotonic Dystrophy / genetics
  • Nucleic Acid Denaturation
  • Nucleic Acid Hybridization
  • Oligonucleotides*
  • Pedigree
  • Repetitive Sequences, Nucleic Acid*
  • Templates, Genetic


  • Oligonucleotides
  • DNA Ligases