OBJECTIVES:

We have recently shown that circulatory fetal DNA levels are elevated in preeclampsia, even before the onset of symptoms. Most studies, however, quantified circulatory male fetal DNA with real-time PCR assays for the single-copy SRY locus on the Y chromosome. We have now examined both the SRY assay for the single-copy locus and the DYS14 assay for the multi-copy locus in parallel on a cohort of 505 pregnant women, 16 of whom later developed preeclampsia.

MATERIAL-METHODS:

Pregnant women at approximately 21 weeks of gestation were recruited for this study. Circulatory fetal DNA in maternal plasma samples was quantified by real-time PCR assays specific for the SRY and DYS14 loci.

RESULTS:

Circulatory fetal DNA levels were significantly elevated in those patients who subsequently developed preeclampsia when compared to those with uncomplicated deliveries and those complicated by chronic hypertension and IUGR. The SRY and DYS14 real-time PCR assays in this study achieved more than 97 % accuracy for identification of fetal gender. The two approaches present a good diagnostic test to predict preeclampsia prior to the onset of symptoms.

CONCLUSIONS:

Our data confirm that circulatory fetal DNA levels are elevated early in pregnancy in those patients who subsequently develop preeclampsia. The data suggest that circulatory male fetal DNA levels can be used as risk markers for earlier diagnosis of preeclampsia by both the DYS14 and SRY specific real-time PCR assays for the multi-copy and single-copy loci.

Keywords: circulatory fetal DNA, maternal plasma, preeclampsia, prediction validation