Robust amplification and ethidium-visible detection of the fragile X syndrome CGG repeat using Pfu polymerase

Am J Med Genet. 1994 Jul 15;51(4):522-6. doi: 10.1002/ajmg.1320510447.


We report on a method for ethidium bromide detection of FMR1 normal and premutation-size CGG triplet repeats. A set of PCR conditions has been optimized for the polymerase of the hyperthermophilic bacterium, Pyrococcus furiosus. Using this protocol, normal-size alleles ranging from 5 to 50 repeats, as well as most of premutation-size alleles, varying from > 50 to approximately 200 repeats, could be detected by ethidium bromide staining of agarose gels. Since the protocol requires neither autoradiography nor polyacrylamide gel electrophoresis, it promises to provide a rapid means for the exclusion of fragile X syndrome in males with mental retardation.

Publication types

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

MeSH terms

  • Base Sequence
  • DNA Mutational Analysis
  • DNA Primers
  • DNA-Directed DNA Polymerase*
  • Diagnosis, Differential
  • Electrophoresis, Agar Gel
  • Ethidium*
  • Fragile X Syndrome / diagnosis*
  • Fragile X Syndrome / genetics
  • Gene Dosage
  • Humans
  • Intellectual Disability / genetics
  • Male
  • Molecular Sequence Data
  • Pedigree
  • Polymerase Chain Reaction / methods*
  • Repetitive Sequences, Nucleic Acid*


  • DNA Primers
  • Pfu DNA polymerase
  • DNA-Directed DNA Polymerase
  • Ethidium