Cell-free DNA screening for common autosomal trisomies using rolling-circle replication in twin pregnancies

ObjectiveTo evaluate the performance of prenatal screening for common autosomal trisomies in twin pregnancies through the use of rolling-circle replication (RCR)-cfDNA as a first-tier test.MethodProspective multicenter study. Women who underwent prenatal screening for trisomy (T) 21, 18 and 13 between January 2019 and March 2022 in twin pregnancies were included. Patients were included in two centers. The primary endpoint was the rate of no-call results in women who received prenatal screening for common autosomal trisomies by RCR-cfDNA at the first attempt, compared to that in prospectively collected samples from 16,382 singleton pregnancies. The secondary endpoints were the performance indices of the RCR-cfDNA.Results862 twin pregnancies underwent screening for T21, T18 and T13 by RCR-cfDNA testing at 10-33 weeks' gestation. The RCR-cfDNA tests provided a no-call result from the first sample obtained from the patients in 107 (0.7%) singleton and 17 (2.0%) twin pregnancies. Multivariable regression analysis demonstrated that significant independent predictors of test failure were twin pregnancy and in vitro fertilization conception. All cases of T21 (n = 20/862; 2.3%), T18 (n = 4/862; 0.5%) and T13 (n = 1/862; 0.1%) were correctly detected by RCR-cfDNA (respectively, 20, 4 and 1 cases). Sensitivity was 100% (95% CI, 83.1%-100%), 100% (95% CI 39.8%-100%) and 100% (95% CI 2.5%-100%) for T21, T18 and T13, respectively, in twin pregnancies.Results862 twin pregnancies underwent screening for T21, T18 and T13 by RCR-cfDNA testing at 10-33 weeks' gestation. The RCR-cfDNA tests provided a no-call result from the first sample obtained from the patients in 107 (0.7%) singleton and 17 (2.0%) twin pregnancies. Multivariable regression analysis demonstrated that significant independent predictors of test failure were twin pregnancy and in vitro fertilization conception. All cases of T21 (n = 20/862; 2.3%), T18 (n = 4/862; 0.5%) and T13 (n = 1/862; 0.1%) were correctly detected by RCR-cfDNA (respectively, 20, 4 and 1 cases). Sensitivity was 100% (95% CI, 83.1%-100%), 100% (95% CI 39.8%-100%) and 100% (95% CI 2.5%-100%) for T21, T18 and T13, respectively, in twin pregnancies.ConclusionThe RCR-cfDNA test appears to have good accuracy with a low rate of no-call results in a cohort of twin pregnancies for the detection of the most frequent autosomal trisomies. What's already know about this topic?Most technologies involving cell-free DNA (cfDNA) and used for common autosomal trisomy screening require the use of massive parallel sequencing. A new technology has recently emerged, based on rolling-circle replication (RCR).What does this study add?The RCR-cfDNA test has a low rate of no-call results in a cohort of twin pregnancies for the detection of the most frequent common autosomal trisomies. The no-call rate appears independently higher in twin pregnancies than in singleton pregnancies. The RCR-cfDNA test has a good accuracy in a cohort of twin pregnancies for the detection of the most frequent common autosomal trisomies. Obtaining a pregnancy by in vitro fertilization (IVF) increases the probability of obtaining a no-call result.