Real-time PCR with molecular beacons provides a highly accurate assay for detection of Tay-Sachs alleles in single cells

Prenat Diagn. 2002 Dec;22(12):1130-4. doi: 10.1002/pd.500.


The results presented here provide the first single-cell genetic assay for Tay-Sachs disease based on real-time PCR. Individual lymphoblasts were lysed with an optimized lysis buffer and assayed using one pair of primers that amplifies both the wild type and 1278 + TATC Tay-Sachs alleles. The resulting amplicons were detected in real time with two molecular beacons each with a different colored fluorochrome. The kinetics of amplicon accumulation generate objective criteria by which to evaluate the validity of each reaction. The assay had an overall utility of 95%, based on the detection of at least one signal in 235 of the 248 attempted tests and an efficiency of 97%, as 7 of the 235 samples were excluded from further analysis for objective quantitative reasons. The accuracy of the assay was 99.1%, because 228 of 230 samples gave signals consistent with the genotype of the cells. Only two of the 135 heterozygous samples were allele drop-outs, a rate far lower than previously reported for single-cell Tay-Sachs assays using conventional methods of PCR.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Alleles
  • Biological Assay / methods
  • Cell Line
  • DNA Probes / chemistry
  • Female
  • Genotype
  • Humans
  • Lymphocytes / cytology
  • Pregnancy
  • Preimplantation Diagnosis / methods*
  • Reproducibility of Results
  • Reverse Transcriptase Polymerase Chain Reaction / methods*
  • Tay-Sachs Disease / diagnosis
  • Tay-Sachs Disease / genetics*


  • DNA Probes