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Objective: Maternal plasma is a source of circulating placental nucleic acids. In this study, we validated previous observations on abnormal levels of circulating messenger RNA (mRNA) for the tenascin-X gene in pregnancies with ventricular septal defects in the second trimester of pregnancy. Methods: This was a bicentric retrospective study conducted from March 2016 to July 2017. Real-time polymerase chain reaction was used to identify abnormally expressed genes, comparing ten women carrying a euploid fetus with ventricular septal defects to 30 controls at 19–24 weeks of gestation. The univariable analysis was used to determine whether the mean mRNA for the tenascin-X gene values would differ from the expected values for the controls. Results: mRNA for tenascin-X gene values was higher in ventricular septal defects, 4.38 ± 3.01 versus 1.00 ± 0.80. The result was still significant even after adjustment for gestational age. Conclusions: These data confirm previous studies on the specific association of mRNA species and type of congenital heart defect and confirm that ventricular septal defects are associated with abnormal mRNA for the tenascin-X gene. The positive predictive value of this molecular marker in the general population should be assessed through prospective studies.

Objective: Our objective was to retrospectively evaluate whether the levels of cell-free DNA (cfDNA) fetal fraction differed in the first trimester of pregnancies between controls and those who subsequently developed early- or late-onset fetal growth restriction (FGR). Methods: This was a case–control study conducted between May 2015 and May 2018 in 231 low-risk women who had received first trimester screening for major fetal aneuploidies (Panorama, Natera, San Carlos, CA, USA). Early- and late-onset FGR developed in 5 and 16 women, respectively, according to Delphi criteria. Multiples of median (MoM) were used to evaluate the differences in cfDNA fetal fraction between cases and controls. cfDNA fetal fraction was adjusted for gestational age (from 10 + 0 to 13 + 6 gestational weeks) and maternal weight (43–96 kg). Results: The median cfDNA fetal fractions for controls and early- and late-onset FGR were 1.00 (interquartile range [IQR] 0.89–1.12), 0.69 (IQR 0.44–0.84) and 0.93 (IQR 0.83–1.03) MoM, respectively. Statistically lower cfDNA fetal fraction MoM values were observed only in patients with early-onset FGR (Kruskal–Wallis test with Dunn post hoc test). In a 1:35 ratio (one case of early-onset FGR: 35 controls), the mean observed rank of 2.00 ± 2.23 in the cases was significantly lower than the expected 18.97 ± 10.17 (p < 0.001). Conclusions: Low-risk pregnancies that developed early-onset FGR had lower cfDNA fetal fractions than did the matched controls. This result is consistent with the placental dysfunction typical of early-onset FGR. For possible clinical use, the cfDNA fetal fraction would yield a better predictive value if adjusted for maternal weight, since maternal weight affects both cfDNA fetal fraction and the occurrence of FGR.

Panorama Plus (Natera), a single-nucleotide polymorphism- (SNP-) based approach that relies on the identification of maternal and fetal allele distributions, allows the detection of common aneuploidies and also incorporates a panel of 5 microdeletions including Di George syndrome. We report here the first case of Di George syndrome detected by NIPT in Italy; blood was drawn at 12 weeks’ gestation. The patient had an amniocentesis to confirm the diagnosis by MLPA (multiplex ligation-dependent probe amplification) and an ultrasound aimed to detect the features associated with the syndrome. A right aortic arch and suspect of thymus atrophy were detected, but not other severe malformations typical of the disease. The patient terminated the pregnancy at 17 weeks. NIPT allowed an early screening of Di George syndrome. As the patient was at low risk, it is likely that an ultrasound would have missed the condition.

Objective: To verify the hypothesis that aberrant placental mRNA genes related to cardiogenesis can be detected in maternal plasma at the second trimester of pregnancy. Methods: NanoString technology was used to identify aberrant genes, comparing 39 women carrying a fetus with a congenital heart defect (CHD) to 31 controls at 19–24 weeks of gestation. The genes with differential expression were subsequently tested using real time polymerase chain reaction. Linear discriminant analysis (LDA) was used to combine all the mRNA species with discriminant ability for CHD. A multivariable receiver operating characteristic (ROC) curve having the estimated discriminant score as an explanatory variable was generated. Results: Six genes with differential expression, namely FALZ, PAPP-A, PRKACB, SAV1, STK4 and TNXB2, were found. The ROC curve yielded a detection rate of 66.7% at a false positive rate of 10%. A higher discriminant score (>75th centile) was reached for 14 CHD cases (82.4%) and only 1 control (5.8%). Two cases (11.8%) of heart rhythm disorders also yielded a discriminant score value >75th centile. Conclusion: These data represent a step forward in the screening of CHDs. Additional studies are needed to detect more mRNAs with discriminant ability and to move the first trimester screening.

Objective The aim of this study was to present a new method for fetal Kell genotyping by means of the allelic discrimination of K1 and K2 in real-time polymerase chain reaction (PCR). Methods Real-time quantitative polymerase chain reaction incorporating an allele-specific primer was developed for detecting the K allele of KEL. Results By means of this method, the K1/K2 genotype was able to be determined in all blood samples analyzed. Results using cell-free fetal DNA (cffDNA) from two Kell-negative pregnant women confirmed the Kell-positive genotype of fetuses. The real-time PCR analysis also allowed the determination of the fetal fraction using the quantification of Kell-positive DNA. Conclusion An efficient and reliable strategy for Kell genotyping is herein presented. The method was optimized on cffDNA to create a non-invasive prenatal test which could be routinely used for the prevention of hemolytic disease of the fetus and the newborn (HDFN).