Detection of trisomy 21 by quantitative fluorescent-polymerase chain reaction in uncultured amniocytes

Prenat Diagn. 2003 Apr;23(4):287-91. doi: 10.1002/pd.579.


Prenatal diagnosis of fetal trisomy 21 is usually performed by cytogenetic analysis. This requires lengthy laboratory procedures, high costs and is unsuitable for large-scale screening of pregnant women. Today, trisomy 21 can be rapidly diagnosed within 24 h by molecular analysis of uncultured fetal cells using the semi-quantification of fluorescent PCR products from short tandem repeat (STR) polymorphic markers. The aim of our study was to test a chromosome quantification method on the basis of the analysis of fluorescent PCR products derived from non-polymorphic target genes. Co-amplification of a portion of DSCR1 (Down syndrome Critical Region 1) and the reference gene, CFTR (cystic fibrosis transmembrane regulator) enabled molecular detection of trisomy 21. Our method was successfully tested on a total of 154 amniotic fluids in a blind prospective study. Calculation of the DSCR1/CFTR ratio allowed us to distinguish between 152 normal amniotic fluids (mean ratio 0.99) and 2 amniotic fluids presenting a trisomy 21 status (DSCR1/CFTR ratio of 1.53 and 1.61, respectively). The results obtained by conventional cytogenetic analysis and our quantitative PCR method were concordant in every case. Our gene-based fluorescent PCR approach represents an alternative molecular method for rapid and reliable detection of trisomy 21, which can be helpful in the prenatal diagnosis of women at high risk of fetal trisomy 21.

MeSH terms

  • Adult
  • Amniocentesis*
  • Amniotic Fluid / chemistry*
  • Amniotic Fluid / cytology
  • Cystic Fibrosis Transmembrane Conductance Regulator / genetics
  • Cystic Fibrosis Transmembrane Conductance Regulator / metabolism
  • DNA-Binding Proteins
  • Down Syndrome / diagnosis*
  • Down Syndrome / genetics
  • Female
  • Humans
  • Intracellular Signaling Peptides and Proteins
  • Mass Screening / methods*
  • Maternal Age
  • Minisatellite Repeats / genetics
  • Muscle Proteins / genetics
  • Muscle Proteins / metabolism
  • Polymerase Chain Reaction / methods*
  • Pregnancy
  • Pregnancy, High-Risk
  • Prospective Studies
  • Repetitive Sequences, Nucleic Acid
  • Reproducibility of Results
  • Single-Blind Method
  • Spectrometry, Fluorescence / methods*


  • CFTR protein, human
  • DNA-Binding Proteins
  • Intracellular Signaling Peptides and Proteins
  • Muscle Proteins
  • RCAN1 protein, human
  • Cystic Fibrosis Transmembrane Conductance Regulator