Rapid determination of trisomy 21 from amniotic fluid cells using single-nucleotide polymorphic loci.
OBJECTIVE
Rapid detection of trisomy 21 is an important goal for prenatal genetic centers. Fluorescent-PCR and DNA fragment analysis was developed a decade ago and thousands of samples were analyzed in routine practice using this method. Quantitative real-time PCR with melting curve analysis using SNP markers for trisomy 21 detection was described recently. We studied the reliability of this method on a cohort of samples of Hungarian patients.


METHODS
DNA was isolated with silica adsorption method from amniotic fluid cells. We investigated 67 trisomy 21 and 62 diploid samples in the study. Quantitative real-time PCR was performed using hybridization probes combined with melting curve analysis. Peak areas under the derivative curves were determined and analyzed.


RESULTS
The SNP marker WIAF 899 was informative in 41.86% of cases and WIAF 2643 in 48.83%. The melting curve area ratios were significantly different between trisomic and normal cases for WIAF 899 (trisomic 0.5246 +/- 0.2498 vs 0.8347 +/- 0.5234; p < 0.001), while in the case of WIAF 2643, they were not different.


CONCLUSIONS
Combined and selected SNP markers could be valuable tools for rapid trisomy 21 detection in prenatal genetic screening.
Nagy
Bálint
B
First Department of Obstetrics and Gynecology, Semmelweis University, Budapest, Hungary. nabal@noi1.sote.hu
Bán
Zoltán
Z
Lázár
Levente
L
Nagy
Richárd Gyula
RG
Papp
Csaba
C
Tóth-Pál
Erno
E
Papp
Zoltán
Z
D000483:Alleles; D000653:Amniotic Fluid / Q000166:cytology*; D004247:DNA / Q000737:chemistry / Q000302:isolation & purification; D004314:Down Syndrome / Q000175:diagnosis*; D005820:Genetic Testing / Q000379:methods / Q000592:standards; D006801:Humans; D009693:Nucleic Acid Hybridization; D016133:Polymerase Chain Reaction; D020641:Polymorphism, Single Nucleotide; D011296:Prenatal Diagnosis / Q000379:methods* / Q000592:standards; D015203:Reproducibility of Results; D013997:Time Factors
D004247:DNA