Quantitative Abnormalities of Fetal DNA in Maternal Serum in Preeclampsia

Abstract

There is much recent interest in the biologic and diagnostic implication of cell-free non-host DNA in the plasma and serum of human subjects. To determine if quantitative abnormalities of circulating non-host DNA may be associated with certain pathologic processes, we used circulating fetal DNA in preeclampsia as a model system. We studied 20 preeclamptic women and 20 control subjects of comparable gestational age (means, 32 and 33 weeks, respectively). Male fetal DNA in maternal serum was measured using real-time quantitative PCR for the SRY gene on the Y chromosome. The imprecision (CV) of the assay was 2.7%. The median circulating fetal DNA was increased fivefold in 20 preeclamptic women compared with 20 control pregnant women (381 vs 76 genome-equivalents/mL, P <0.001). These observations suggest that preeclampsia is associated with disturbances in the liberation and/or clearance mechanisms of circulating DNA. These results also raise the possibility that measurement of circulating DNA may prove useful as a marker for the diagnosis and/or monitoring of preeclampsia.