Moreover, the gene copy number in mcf-DNA was significantly higher than that in mev-DNA for the <i>RASSF1A, ERG,</i> and <i>UMODL1 (U1</i> and <i>U2)</i> genes in trisomy pregnancies.<h4>Conclusion</h4>This pilot study demonstrates the feasibility of using mcf-DNA and mev-DNA for detecting Trisomy 21-associated fetal methylation signatures in maternal plasma. Here, ERG is linked to trisomy 21.