The bivariate NRIP1/ZEB2 RNA marker permits non-invasive presymptomatic screening of pre-eclampsia

Using genome-wide transcriptome analysis by RNA sequencing of first trimester plasma RNA, we tested whether the identification of pregnancies at risk of developing pre-eclampsia with or without preterm birth or growth restriction is possible between weeks 9-14, prior to the appearance of clinical symptoms. We implemented a metaheuristic approach in the self-learning SVM algorithm for differential gene expression analysis of normal pregnancies (n=108), affected pregnancies (n=34) and non-pregnant controls (n=19). Presymptomatic candidate markers for affected pregnancies were validated by RT-qPCR in first trimester samples (n=34) from an independent cohort. PRKG1 was significantly downregulated in a subset of pregnancies with birth weights below the 10thpercentile as shared symptom. The NRIP1/ZEB2 ratio was found to be upregulated in pregnancies with pre-eclampsia or trisomy 21. Complementary quantitative analysis of both the linear and circular forms of NRIP1 permitted discrimination between pre-eclampsia and trisomy 21. Pre-eclamptic pregnancies showed an increase in linear NRIP1 compared to circular NRIP1, while trisomy 21 pregnancies did not.