Parental Psychological Distress of Missed Diagnosis of Down Syndrome at Antenatal Screening: A Rare, but Still Real Occurrence - A Case Report and Review of Literature

INTRODUCTION

Prenatal screening programs are important components for pregnant women care and are often linked with grief and shock based on gestational age or the diagnosis. Lower/no sensitivity is also associated with these screening programs leading to providing false-negative outputs.

CASE PRESENTATION

Present work shows a case of missed antenatal diagnosis of Down syndrome and its persistant medical and psychological impact on the family members. We have also discussed the relevant economic and medical-legal issues related to the context and aimed to maintain an adequate awareness among healthcare to discuss properly these investigations (difference between screening and diagnostic testing), their possible outcome (chances of false results) and enabled the pregnant women/couple to take informed decision on early pregnancy.

CONCLUSION

These programs are considered as routine clinical practice in many countries from last few years and are necessary to assess the pros and cons of these programs. One of the prime cons involves the likeliness of obtaining a false-negative result due to lack of 100% sensitivity and specificity.

Noninvasive Detection of Fetal Aneuploidy Using Next Generation Sequencing

Cell-free DNA (cfDNA)-based noninvasive prenatal testing (NIPT) utilizing next generation sequencing (NGS) is a highly sensitive and specific approach designed to screen for fetal aneuploidy. NIPT was first introduced in 2011 and has been rapidly adopted in a clinical setting because of the improved performance afforded compared with traditional prenatal serum screening options. We describe a PCR-free, paired-end sequencing-based NIPT, the VeriSeq NIPT Solution. This NIPT screens for fetal aneuploidy of chromosomes 21, 18, 13, X, and Y. Using the validated approach detailed here, users can achieve high sensitivities and specificities for trisomies 21, 18, and 13 as well as sex chromosome aneuploidies with low failure rates. The automated workflow can be completed in 1 day, with only 2 h of hands-on time from a single technician.

Effective Fetal Epigenetic Biomarkers for Noninvasive Fetal Trisomy 21 Detections

INTRODUCTION

Recently, we identified three novel fetal-specific epigenetic DNA regions (FSERs) on chromosome 21 for detection of noninvasive fetal trisomy 21 (T21). In this study, the diagnostic accuracies of the three FSERs were assessed on a larger panel of the first-trimester pregnant women.

MATERIAL AND METHODS

This study was conducted with maternal plasma collected from 167 pregnant women carrying 155 chromosomally normal and 12 T21 fetuses (10-13 gestational weeks). Accuracies of FSERs for noninvasive prenatal test of fetal T21 were estimated by the area under the receiver operator characteristic curve (AUC).

RESULTS

The levels of all FSERs increased in pregnant women with T21 fetuses when compared with controls (p < 0.001 for all). The levels of the three FSERs did not differ according to maternal age, body mass index, and fetal sex at maternal blood sampling (p > 0.05 for all). In noninvasive fetal T21 detection, the AUC of FSER1, FSER2, and FSER3 were 0.859 (95% CI: 0.746-0.972), 0.919 (95% CI: 0.856-0.982), and 0.868 (95% CI: 0.746-0.990), respectively.

DISCUSSION

The findings of this study suggest that all FSERs may be useful for noninvasive fetal T21 detection, regardless of maternal age, body mass index, and fetal sex.

Does Maternal Body Mass Index Affect the Quantity of Circulating Fetal Cells Available to Use for Cell-Based Noninvasive Prenatal Test in High-Risk Pregnancies?

We present the first study that investigates the effect of maternal body mass index (BMI) on the quantity of circulating fetal cells available to use in cell-based noninvasive prenatal test (cbNIPT). cbNIPT has been proposed as a superior alternative to noninvasive prenatal test from cell-free fetal DNA. Kølvraa et al. [Prenat Diagn. 2016 Dec; 36(12): 1127-34] established that cbNIPT can be performed on as few as one fetal cell, and Vestergaard et al. [Prenat Diagn. 2017 Nov; 37(11): 1120-4] demonstrated that these fetal trophoblast cells could be used successfully in cbNIPT to detect chromosomal and sub-chromosomal abnormalities. This study on 91 pregnant women with high-risk pregnancies suggests that cbNIPT should not be hampered by an increased BMI because every pregnancy, irrespective of the BMI, has rendered fetal cells for downstream genetic analysis. The mean number of fetal cells per sample was 12.6, with a range of 1-43 cells in one sample. ANOVA showed that increasing maternal BMI tends to decrease the number of fetal cells, but not significantly.