Optimized Real-Time Quantitative PCR Measurement of Male Fetal DNA in Maternal Plasma
- 1 September 2005
- journal article
- Published by Oxford University Press (OUP) in Clinical Chemistry
- Vol. 51 (9), 1598-1604
- https://doi.org/10.1373/clinchem.2005.051235
Abstract
Background: Circulating fetal DNA (cfDNA) in maternal plasma has been measured to investigate its possible relationship with pregnancy-related disorders, including fetal trisomy 21 and preeclampsia. The circulating concentrations of single-copy fetal genes, however, are close to the detection limits of PCR methods. Methods: We optimized a protocol for the real-time quantitative PCR amplification of the multicopy sequence DYS14 on the Y-chromosome. This was compared with an established real-time PCR assay for the single-copy SRY gene. Results: By probit regression analysis, the measurements of male DNA by the DYS14 assay had a 10-fold lower detection limit (0.4 genome equivalents) than did measurements of SRY. For plasma samples from women in the first trimester of pregnancy, imprecision (CV) was 2%–22% when amplifying DYS14 compared with 26%–140% for SRY. Conclusions: The low copy numbers of fetal DNA in plasma of women in the first trimester of pregnancy cannot be measured precisely when targeting single-copy sequences. Better results are obtained by amplifying a sequence that is present in multiple copies per male genome.Keywords
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