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Updated: Oct 19, 2025
Pre-Implantation Genetic Testing for Aneuploidy on a Semiconductor Based Next-Generation Sequencing Platform
Published on: August 17, 2022
Cell-free DNA screening for fetal aneuploidy using the rolling circle method: A step towards non invasive prenatal
Enza Pavanello1, Andrea Sciarrone2, Varvara Guaraldo1
1Department of Laboratory Medicine, Azienda Ospedaliera Universitaria Città della Salute e della Scienza, Turin, Italy.
Objective:
To assess the efficacy of cell-free (cf)DNA screening for aneuploidy using the automated system based on rolling circle replication.
Methods:
A prospective study among women referred for invasive prenatal diagnosis between July 2018 and December 2019. The plasma fraction was extracted within 5 days from blood collection, stored at -20°C and cfDNA measured between January and December 2019.
Results:
A total of 805 women were recruited; 778 with singleton pregnancies and 27 twins. There were 48 Down syndrome, 25 Edwards syndrome and 3 Patau syndrome cases. Overall, the no-call rate was 2.6% (95% confidence interval 1.6%-3.9%) which reduced from 4.7% to 1.1% after relocation of the system (p < 0.002) to ensure a constant ambient temperature below 25°C. In singletons the Down syndrome detection rate (DR) was 100% (93%-100%) and false-positive rate (FPR) 0.14% (0.00%-0.79%). The Edwards syndrome DR was 96% (80%-100%) and FPR 0.78% (0.29%-1.7%). One false-positive had a confined placental trisomy 18 and the remaining five a z-score requiring sample repetition; all the false-positives occurred before system relocation (p < 0.005). Patau syndrome DR and FPR were 67% (9.4%-99%) and 0.26% (0.03%-0.95%).
Conclusion:
The cfDNA rolling circle method yields similar results to other methods provided that room temperature is adequately controlled.
