Clinical performance of DNA-based prenatal screening using single-nucleotide polymorphisms approach in Thai women with singleton pregnancy

Effects of an animated educational video on knowledge of cell-free DNA screening among Thai pregnant women: a randomized control trial

BACKGROUND

In developing countries, pregnant women have insufficient knowledge about cell-free DNA screening. Reports from developed countries have found that various tools in prenatal genetic counseling can improve the knowledge of pregnant women who undergo cell-free DNA screening. Data are limited from developing countries where women have different baseline socio-educational backgrounds. The objective of this study was to compare the effects of an animated educational video combined with traditional counseling versus traditional counseling alone in changing pregnant women's knowledge of cell-free DNA screening.

METHODS

This study was a randomized control trial at an antenatal clinic. Eligible subjects who were Thai pregnant women, were randomized to either view or not view the 4-minute animated educational video explaining cell-free DNA screening. Both groups received traditional counseling. The women were asked to complete a Thai questionnaire assessing knowledge of the screening before and after intervention. The questionnaire consisted of three sections: demographic data of the research participants and their existing awareness about cell-free DNA testing; performance and limitations of cell-free DNA screening; and participants' attitudes toward the positive screening. Primary outcome was the change in knowledge scores. Secondary outcomes were attitudes toward positive screening test, levels of satisfaction with counseling, and screening acceptance rates.

RESULTS

Data from 83 women in the video group and 82 in the non-video group were analyzed. The knowledge score (range 0-18) change after counseling was significantly higher in the video group than the non-video group (+ 7.1 ± 3.3 vs + 4.2 ± 2.5; p = 0.03). There were no significant differences in attitudes toward positive screening test (p = 0.83), levels of satisfaction (p = 0.24), or screening acceptance rates (p = 0.15) between the groups.

CONCLUSIONS

Adding the video to traditional counseling was better than traditional counseling alone in improving pregnant women's knowledge about cell-free DNA screening.

TRIAL REGISTRATION

The study was retrospectively registered with the Thai Clinical Trials Registry (TCTR20210917001, 17/09/2021).

The accuracy of prenatal cell-free DNA screening for sex chromosome abnormalities: A systematic review and meta-analysis

OBJECTIVE

Although cell-free DNA screening for sex chromosome abnormalities is increasingly used in clinical practice, its diagnostic accuracy and clinical utility remain unclear. This systematic review and meta-analysis aimed to determine the performance of cell-free DNA in the detection of sex chromosome abnormalities.

DATA SOURCES

Medline and PubMed, Embase, and Web of Science were searched from inception to January 2022 for articles relating to cell-free DNA screening for sex chromosome abnormalities.

STUDY ELIGIBILITY CRITERIA

Original articles, randomized control trials, conference abstracts, cohort and case-control studies, and case series with more than 10 cases with diagnostic confirmation were considered for inclusion.

METHODS

Quality assessment of each included publication was performed using the Quality Assessment of Diagnostic Accuracy Studies 2 tool. The positive predictive value was calculated as the proportion of true positive cases among those who tested positive and underwent diagnostic testing. Sensitivity and specificity were pooled, and a summary receiver operating characteristic curve was produced using bivariate models that included studies that had diagnostic confirmation for high- and low-risk women.

RESULTS

The search identified 7553 results. Of these, 380 proceeded to the full-text screening, of which 94 articles were included in the meta-analysis with a total of 1,531,240 women tested. All studies reported a confirmatory genetic test. The pooled positive predictive value was 49.4% (95% confidence interval, 45.8-53.1). The pooled positive predictive value was 32.0% (95% confidence interval, 27.0%-37.3%) for monosomy X, 67.6% (95% confidence interval, 62.5%-72.5%) for XXY, 57.5% (95% confidence interval, 51.7%-63.1%) for XXX, and 70.9% (95% confidence interval, 63.9%-77.1%) for XYY. The pooled sensitivity and specificity of cell-free DNA for sex chromosome abnormalities were 94.1% (95% confidence interval, 90.8%-96.3%) and 99.5% (95% confidence interval, 99.0%-99.7%), respectively, with an area under the summary receiver operating characteristic curve of 0.934 (95% confidence interval, 0.907-0.989).

CONCLUSION

Although the sensitivity and specificity of cell-free DNA for sex chromosome abnormalities are high, the positive predictive value was approximately 50%. The positive predictive value was higher for sex chromosome abnormalities with a supernumerary Y chromosome and lower for monosomy X. Clinicians should inform couples about these findings when offering cell-free DNA for sex chromosome abnormalities.

A Critical Evaluation of Validation and Clinical Experience Studies in Non-Invasive Prenatal Testing for Trisomies 21, 18, and 13 and Monosomy X

Non-invasive prenatal testing (NIPT) for trisomies 21, 18, 13 and monosomy X is widely utilized with massively parallel shotgun sequencing (MPSS), digital analysis of selected regions (DANSR), and single nucleotide polymorphism (SNP) analyses being the most widely reported methods. We searched the literature to find all NIPT clinical validation and clinical experience studies between January 2011 and January 2022. Meta-analyses were performed using bivariate random-effects and univariate regression models for estimating summary performance measures across studies. Bivariate meta-regression was performed to explore the influence of testing method and study design. Subgroup and sensitivity analyses evaluated factors that may have led to heterogeneity. Based on 55 validation studies, the detection rate (DR) was significantly higher for retrospective studies, while the false positive rate (FPR) was significantly lower for prospective studies. Comparing the performance of NIPT methods for trisomies 21, 18, and 13 combined, the SNP method had a higher DR and lower FPR than other methods, significantly so for MPSS, though not for DANSR. The performance of the different methods in the 84 clinical experience studies was consistent with validation studies. Clinical positive predictive values of all NIPT methods improved over the last decade. We conclude that all NIPT methods are highly effective for fetal aneuploidy screening, with performance differences across methodologies.

Clinical performance of DNA-based prenatal screening using single-nucleotide polymorphisms approach in Thai women with singleton pregnancy

Background

To review the performance of noninvasive prenatal screening (NIPS) using targeted single‐nucleotide polymorphisms (SNPs) approach in mixed‐risk Thai women.

Methods

Retrospective analysis of data for detection of trisomy 21 (T21), 18 (T18), 13 (T13), monosomy X (XO), other sex chromosome aneuploidies (SCA), and triploidy/vanishing twins (VT) from a single commercial laboratory.

Results

Mean (±SD) gestational age and maternal weight were 13.2 (±2.1) weeks and 125.7 (±22.4) pounds, respectively (n = 8,572). From 462/8,572 (5.4%) no‐calls; 1/462 (0.2%) was uninformative SNPs, and 1/462 chose amniocentesis. Redraw settled 323/460 (70%) samples with low fetal fraction (FF); and 8,434/8,572 (98.4%) were finally reportable, with 131 high risks (1.6%). The median (min‐max) FF of reportable (n = 8,434) and unreportable samples (n = 137) samples were 10.5% (2.6–37.9) and 3.8% (1–14.1), respectively (p < .05). Fetal karyotypes were available in 106/131 (80.9%) and 52/138 (37.7%) high risk and repeated no‐calls, respectively. The positive predictive values (PPVs) for T21 (n = 47), T18 (n = 15), T13 (n = 7), XO (n = 8), other SCA (n = 7), and triploidy/VT were 94%, 100%, 58.3%, 66.7%, 70%, and 57.1%, respectively. None of repeated no‐calls had aneuploidies.

Conclusion

SNP‐based NIPS has high PPVs for T21 and T18. Although the proprietary SNPs library is not population‐specific, uninformative SNPs are uncommon.