Noninvasive prenatal screening for fetal aneuploidy, 2016 update: a position statement of the American College of Medical Genetics and Genomics

The performance evaluation of NIPT for fetal chromosome microdeletion/microduplication detection: a retrospective analysis of 68,588 Chinese cases

Background

Chromosomal abnormalities are the main cause of birth defects in newborns. Since the inception of noninvasive prenatal testing (NIPT) technology, it has primarily been applied to the detection of common trisomy (T21, T18, T13). However, the application of NIPT in microdeletion and microduplication detection is still controversial.

Methods

This study retrospectively analyzed the data of 68,588 cases that underwent NIPT at Ganzhou Maternal and Child Health Hospital in China. These data were used to evaluate the performance of NIPT in fetal chromosome microdeletion/microduplication detection and to investigate the key factors affecting the NIPT performance.

Results

A total of 281 cases (0.41%) had positive NIPT results with copy number variants (CNVs), of which 161 were validated by karyotyping and chromosome microarray analysis (CMA). Among the 161 cases, 92 were confirmed as true positives through karyotyping or CMA, including 61 microdeletion cases and 31 microduplication cases, resulting in a positive predictive value (PPV) of 57.14%. Improvements in library construction methods increased the fraction of cell-free fetal DNA (cffDNA) from 13.76% to 18.44%, leading to a significant improvement in the detection rate (0.47% vs. 0.15%) and PPV (59.86% vs. 28.57%) of NIPT for CNVs.

Conclusion

This study proved the robust performance of NIPT for fetal chromosome microdeletion/microduplication detection. In addition, the cffDNA fraction is a key factor influencing NIPT, with increased cffDNA fraction improving the performance of NIPT.

Prenatal diagnosis, pregnancy determination and follow up of sex chromosome aneuploidy screened by non-invasive prenatal testing from 122 453 unselected singleton pregnancies: A retrospective analysis of 7-year experience

The phenotype of SCA patients are diversities, make prenatal counseling and parental decision-making following the prenatal diagnosis of SCA more complicated and challenging. NIPT has higher sensitivity and specificity in screening trisomy 21 syndrome, but the effectiveness of NIPT in detecting SCA is still controversial. This study is a large-scale retrospective cohort of positive SCA screened from unselected singleton pregnancies by non-invasive prenatal testing (NIPT) from a single prenatal center of a tertiary hospital. Clinical information, indications, diagnostic results, ultrasound findings, pregnancy determinations, and follow-up were reviewed and analyzed. 596 cases of SCA positive were screened out of 122 453, giving a positive detection rate of 0.49%. 510 cases (85.6%) conducted with amniocentesis to detect fetal chromosome, of which 236 were confirmed as true positive of SCA with PPV of 46.3% (236/510). Of the 236 cases confirmed as true positive SCA, 114 cases (48.3%)chose to terminate the pregnancy (93.0%, 65.3%, 15.4% and 10.9% for 45,X, 47,XXY, 47,XXX and 47,XYY, respectively), 122 cases (51.7%) elected to continue the pregnancy. In conclusions, NIPT as a first-tier routine method for screening autosomal aneuploidies, also could play an important role in screening SCA. Low-risk pregnant women are the main indication for the detection of SCA as NIPT test provides to non-selective population. For 47,XXX and 47,XYY with mild phenotype, couples would like to continue the pregnancy. But for 45,X and 47,XXY, parents apt to terminate pregnancy no matter ultrasound abnormalities were found or not.

Maternal Sex Chromosome Aneuploidy Identified through Noninvasive Prenatal Screening: Clinical Profile and Patient Experience

OBJECTIVE

 Noninvasive prenatal screening (NIPS) may incidentally identify maternal aneuploidies that have health implications. We evaluated patients' experience with counseling and follow-up diagnostic testing after NIPS flags a potential maternal sex chromosome aneuploidy (SCA).

STUDY DESIGN

 Patients who underwent NIPS at two reference laboratories between 2012 and 2021 and had test results that were consistent with possible or probable maternal SCA were contacted with a link to an anonymous survey. Survey topics included demographics, health history, pregnancy history, counseling, and follow-up testing.

RESULTS

 A total of 269 patients responded to the anonymous survey, and 83 of these individuals also completed one follow-up survey. Most received pretest counseling. A total of 80% were offered fetal genetic testing during the pregnancy, and 35% of patients completed diagnostic maternal testing. Monosomy X-related phenotypes such as short stature or hearing loss prompted follow-up testing that led to a diagnosis of monosomy X in 14 (6%) cases.

CONCLUSION

 Follow-up counseling and testing after a high-risk NIPS result suggestive of maternal SCA is heterogenous in this cohort and may be frequently incomplete. Health outcomes may be affected by these results and additional research could improve the provision, delivery, and quality of posttest counseling.

KEY POINTS

· NIPS results showing potential SCA could have maternal health implications.. · Variations in counseling and testing after NIPS were observed for women with suspected SCA.. · Comprehensive counseling and diagnostic testing strategies are critical for these patients..

Performance of noninvasive prenatal screening for fetal sex chromosome aneuploidies in a cohort of 116,862 pregnancies

BACKGROUND

Noninvasive prenatal screening (NIPS) has shown good performance in screening common aneuploidies. However, its performance in detecting fetal sex chromosome aneuploidies (SCAs) needs to be evaluated in a large cohort.

RESEARCH DESIGN AND METHODS

In this retrospective observation, a total of 116,862 women underwent NIPS based on DNA nanoball sequencing from 2015 to 2022. SCAs were diagnosed based on karyotyping or chromosomal microarray analysis (CMA). Among them, 2,084 singleton pregnancies received karyotyping and/or CMA. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of NIPS for fetal SCAs were evaluated.

RESULTS

The sensitivity was 97.7% (95%CI, 87.7-99.9), 87.3% (95% CI, 76.5-94.4), 96.1% (95%CI, 86.5-99.5), and 95.7% (95% CI, 78.1-99.9), the PPV was 25.8% (95%CI, 19.2-33.2), 80.9% (95%CI, 69.5-89.4), 79.0% (95%CI, 66.8-88.3), and 53.7% (95%CI, 37.4-69.3) for 45,X, 47,XXY, 47,XXX, and 47,XYY, respectively. The specificity was 94.1% (95%CI, 93.0-95.1) for 45,X, and more than 99.0% for sex chromosome trisomy (SCT). The NPV was over 99.0% for all.

CONCLUSIONS

NIPS screening for fetal SCAs has high sensitivity, specificity and NPV. The PPV of SCAs was moderate, but that of 45,X was lower than that of SCTs. Invasive prenatal diagnosis should be recommended for high-risk patients.

Eliminating first trimester combined testing: Consequences for early detection of significant fetal anomalies

OBJECTIVE

To determine whether implementation of cell-free DNA (cfDNA) testing for aneuploidy as a first-tier test and subsequent abolition of first trimester combined testing (FCT) affected the first trimester detection (<14 weeks) of certain fetal anomalies.

METHODS

We performed a geographical cohort study in two Fetal Medicine Units between 2011 and 2020, including 705 fetuses with prenatally detected severe brain, abdominal wall and congenital heart defects. Cases were divided into two groups: before (n = 396) and after (n = 309) cfDNA introduction. The primary outcome was the first trimester detection rate (<14 weeks) overall and for non-chromosomal anomalies solely.

RESULTS

Overall, gastroschisis, AVSD and HLHS were detected more often in the first trimester in the before group compared to the after group, respectively 54.5% versus 18.5% (p = 0.004), 45.9% versus 26.9% (p = 0.008) and 30% versus 3.4% (p = 0.005). After exclusion of chromosomal anomalies identifiable through cfDNA testing, the detection of AVSD remained higher in the before group (43.3% vs. 9.5%, p = 0.02), leading to a possible earlier gestation at termination. The termination of pregnancy (TOP) rate did not differ among the groups. In the after group, referrals for suspected anomalies following a dating scan between 11 and 14 weeks significantly increased from 17.4% to 29.1% (p < 0.001).

CONCLUSION

This study underscores the value of a scan dedicated to fetal anatomy in the first trimester as we observed a decline in the early detection of certain fetal anomalies (detectable in the first trimester) subsequent to the abolition of FCT.

Prenatal Genome-Wide Cell-Free DNA Screening: Three Years of Clinical Experience in a Hospital Prenatal Diagnostic Unit in Spain

Genome-wide prenatal cell-free DNA (cfDNA) screening can be used to screen for a wide range of fetal chromosomal anomalies in pregnant patients. In this study, we describe our clinical experience with a genome-wide cfDNA assay in screening for common trisomies, sex chromosomal aneuploidies (SCAs), rare autosomal aneuploidies (RAAs), and copy-number variations (CNVs) in about 6000 patients over a three-year period at our hospital's Prenatal Diagnostic Unit in Spain. Overall, 204 (3.3%) patients had a high-risk call, which included 76 trisomy 21, 21 trisomy 18, 7 trisomy 13, 29 SCAs, 31 RAAs, 31 CNVs, and 9 cases with multiple anomalies. The diagnostic outcomes were obtained for the high-risk cases when available, allowing for the calculation of positive predictive values (PPVs). Calculated PPVs were 95.9% for trisomy 21, 77.8% for trisomy 18, 66.7% for trisomy 13, 10.7% for RAAs, and 10.7% for CNVs. Pregnancy and birth outcomes were also collected for the majority of RAA and CNV cases. Adverse perinatal outcomes for some of these cases included preeclampsia, fetal growth restriction, preterm birth, reduced birth weight, and major congenital structural abnormalities. In conclusion, our study showed strong performance for genome-wide cfDNA screening in a large cohort of pregnancy patients in Spain.

Performance Evaluation of Noninvasive Prenatal Testing in Screening Chromosome Disorders: A Single-Center Observational Study of 15,304 Consecutive Cases in China

Objective

This study was to evaluate the performance of noninvasive prenatal testing (NIPT) in detecting fetal chromosome disorders in pregnant women.

Methods

From October 1st, 2017, to December 31th, 2022, a total of 15,304 plasma cell free DNA-NIPT samples were collected for fetal chromosome disorders screening. The results of NIPT were validated by confirmatory invasive testing or clinical outcome follow-up. Further, NIPT performance between low-risk and high-risk groups, as well as singleton pregnancy and twin pregnancy groups was compared. Besides, analysis of 111 false-positive cases was performed.

Results

Totally, NIPT was performed on 15,086 eligible venous blood samples, of which 179 (1.19%) showed positive NIPT results and 68 were further validated to be true positive samples via confirmatory invasive testing or follow-up of clinical outcomes. For common chromosome aneuploidies, sex chromosome abnormalities (SCA) and other chromosomal aneuploidies, the detection sensitivities of NIPT were all 100%, the specificities were 99.87%, 99.70%, and 99.68% and the positive predictive values (PPVs) were 65.45%, 31.82%, and 10.91%, respectively. No statistically significant variance in detection performance was observed among 2987 high-risk and 12,099 low-risk subjects, as well as singleton and twin pregnancy subjects. The concentration of cell-free fetal DNA of 111 false-positive cases ranged from 5.5% to 33.7%, which was higher than the minimum requirement of NIPT.

Conclusion

With stringent protocol, NIPT shows high sensitivity and specificity for detecting fetal chromosome disorders in a large-scale clinical service, helping improving overall pregnancy management.

Approach and Management of Pregnancies with Risk Identified by Non-Invasive Prenatal Testing

This study represents our second investigation into NIPT, involving a more extensive patient cohort with a specific emphasis on the high-risk group. The high-risk group was subsequently divided into two further groups to compare confirmed cases versus unconfirmed via direct methods. The methodology encompassed the analysis of 1400 consecutive cases from a single genetic center in western Romania, where NIPT was used to assess the risk of specific fetal chromosomal abnormalities. All high-risk cases underwent validation through direct analysis of fetal cells obtained via invasive methods, including chorionic villus sampling and amniocentesis. The confirmation process utilized QF-PCR, karyotyping, and SNP-Array methods customized to each case. Results: A high risk of aneuploidy at NIPT was identified in 36 out of 1400 (2.57%) cases and confirmed in 28 cases. The study also detected an increased risk for copy number variations (CNVs) in 1% of cases, confirmed in two instances involving one large microdeletion and one large microduplication. Trisomy 21 was the exclusive anomaly where NIPT confirmed all cases with identified risk. High-risk NIPT results which were not validated by invasive methods, were classified as false positives; parents in these cases determined to continue the pregnancy. In conclusion, NIPT can serve as a screening method for all pregnancies; however, in high-risk cases, an invasive confirmation test is strongly recommended.

Cell-free DNA screening in twin pregnancies

Cell-free DNA (cfDNA) screening for fetal aneuploidies is clinically available and exhibits better performance than conventional serum screening tests. However, data on the clinical performance of cfDNA screening in twin pregnancies are limited. In this review, we summarized the clinical performance and evaluated the feasibility of cfDNA screening in twin pregnancies based on recent studies and recommendations. The performance of cfDNA screening for trisomy 21 in twin pregnancies is similar to that in singleton pregnancies. Specifically, cfDNA screening has a higher detection rate and lower false-positive rate compared with conventional serum screening. Consequently, recent international guidelines from several academic communities have recommended that cfDNA screening for aneuploidy in twin pregnancies could be considered. Moreover, twin pregnancies can present with specific conditions, such as different zygosities and vanishing twins; therefore, individualized counseling and management are required. Further clinical studies with more twin pregnancies are required for a more accurate analysis.

Clinically significant findings in a decade-long retrospective study of prenatal chromosomal microarray testing

BACKGROUND

Chromosomal microarray (CMA) is commonly utilized in the obstetrics setting. CMA is recommended when one or more fetal structural abnormalities is identified. CMA is also commonly used to determine genetic etiologies for miscarriages, fetal demise, and confirming positive prenatal cell-free DNA screening results.

METHODS

In this study, we retrospectively examined 523 prenatal and 319 products-of-conception (POC) CMA cases tested at Nationwide Children's Hospital from 2011 to 2020. We reviewed the referral indications, the diagnostic yield, and the reported copy number variants (CNV) findings.

RESULTS

In our cohort, the diagnostic yield of clinically significant CNV findings for prenatal testing was 7.8% (n = 41/523) compared to POC testing (16.3%, n = 52/319). Abnormal ultrasound findings were the most common indication present in 81% of prenatal samples. Intrauterine fetal demise was the common indication identified in POC samples. The most common pathogenic finding observed in all samples was isolated trisomy 21, detected in seven samples.

CONCLUSION

Our CMA study supports the clinical utility of prenatal CMA for clinical management and identifying genetic etiology in POC arrays. In addition, it provides insight to the spectrum of prenatal and POC CMA results as detected in an academic hospital clinical laboratory setting that serves as a reference laboratory.

Obesity in prenatal medicine: a game changer?

Obesity is recognized by the World Health Organization (WHO) as a disease in its own right. Moreover, obesity is an increasingly concerning public health issue across the world and its prevalence is rising amongst women of reproductive age. The fertility of over-weight and obese women is reduced and they experience a higher rate of miscarriage. In pregnant women obesity not only increases the risk of antenatal complications, such as preeclampsia and gestational diabetes, but also fetal abnormalities, and consequently the overall feto-maternal mortality. Ultrasound is one of the most valuable methods to predict and evaluate pregnancy complications. However, in overweight and obese pregnant women, the ultrasound examination is met with several challenges, mainly due to an impaired acoustic window. Overall obesity in pregnancy poses special challenges and constraints to the antenatal care and increases the rate of pregnancy complications, as well as complications later in life for the mother and child.

Integrating Artificial Intelligence for Advancing Multiple-Cancer Early Detection via Serum Biomarkers: A Narrative Review

The concept and policies of multicancer early detection (MCED) have gained significant attention from governments worldwide in recent years. In the era of burgeoning artificial intelligence (AI) technology, the integration of MCED with AI has become a prevailing trend, giving rise to a plethora of MCED AI products. However, due to the heterogeneity of both the detection targets and the AI technologies, the overall diversity of MCED AI products remains considerable. The types of detection targets encompass protein biomarkers, cell-free DNA, or combinations of these biomarkers. In the development of AI models, different model training approaches are employed, including datasets of case-control studies or real-world cancer screening datasets. Various validation techniques, such as cross-validation, location-wise validation, and time-wise validation, are used. All of the factors show significant impacts on the predictive efficacy of MCED AIs. After the completion of AI model development, deploying the MCED AIs in clinical practice presents numerous challenges, including presenting the predictive reports, identifying the potential locations and types of tumors, and addressing cancer-related information, such as clinical follow-up and treatment. This study reviews several mature MCED AI products currently available in the market, detecting their composing factors from serum biomarker detection, MCED AI training/validation, and the clinical application. This review illuminates the challenges encountered by existing MCED AI products across these stages, offering insights into the continued development and obstacles within the field of MCED AI.

Combined Z-scores to assess the impact of rare autosomal trisomies that results in non-invasive prenatal screening on pregnancy outcomes

OBJECTIVE

This study aimed to combine Z-scores to evaluate the effects of rare autosomal trisomies (RATs) in non-invasive prenatal screening (NIPS) on pregnancy outcomes at a single center.

METHODS

We retrospectively collected the clinical data of women with high-risk RATs results using NIPS at a single center between January 2017 and December 2021. NIPS-positive results were separated into three groups based on the Z-value of RATs (Group1: 6 ≤ Z < 10; Group2: 10 ≤ Z < 15; Group 3: Z ≥ 15). Pregnancy outcomes of women with RATs were compared with the low-risk NIPS group.

RESULTS

Overall, 83 RATs were identified in 23,321 NIPS results at our center. Prenatal diagnosis was conducted for 55 patients, and no case was confirmed, with a positive predictive value (PPV) of zero. Fifteen of these patients had adverse pregnancy outcomes, including delivered preterm and/or birth weight (9/15, 60.0 %), structural abnormalities (4/15, 26.7 %), miscarriage (1/15, 6.7 %), and intrauterine death (1/15, 6.7 %). There were 8 (8/22, 36.4 %) adverse pregnancy outcomes in Group 3, which was significantly higher than that in the low-risk NIPS group (p < 0.01). No significant difference was observed between the control group and Group 1 and Group 2 (p > 0.01).

CONCLUSIONS

Clinicians should pay more attention to the RATs results when the Z-score is ≥ 15. The data are available for clinicians to guide the prenatal diagnosis of RATs and pregnancy management.

Residual risk of clinically significant copy number variations in fetuses with nasal bone absence or hypoplasia after excluding non-invasive prenatal screening-detectable findings

BACKGROUND

It remains controversial whether prenatal screening or diagnostic testing should be offered to fetuses with nasal bone (NB) absence or hypoplasia, and there are no studies comparing the yield of chromosomal microarray analysis (CMA) to non-invasive prenatal screening (NIPS). The aim of this study was to evaluate the residual risk of clinically significant copy number variations (CNVs) in fetuses with NB absence or hypoplasia after excluding theoretically NIPS-detectable abnormalities, and to assess their clinical outcomes.

METHODS

This prospective study encompassed 400 fetuses with NB absence or hypoplasia undergoing CMA testing between 2015 and 2022. Clinically significant CMA findings were categorized into three subgroups, including three-NIPS-detectable (trisomies 21, 18 and 13), five-NIPS-detectable (trisomies 21, 18 and 13 and sex chromosome aneuploidies) and genome-wide NIPS-detectable (variants over 7 Mb). We calculated the theoretical residual risk and compared it with the results of a control cohort of low-risk pregnancies. We further evaluated their clinical outcomes.

RESULTS

The overall diagnostic yield in our cohort was 7.8% (31/400). The detection rate of clinically significant CMA findings in fetuses with non-isolated NB absence or hypoplasia was significantly higher than that in fetuses with isolated NB absence or hypoplasia (20.0% vs. 6.6%, P =.005). The theoretical residual risks in all NIPS models were significantly higher when compared with the control cohort. The normal infant rate in fetuses with normal CMA results was 97.9% (323/330), and a significant higher incidence was observed in fetuses with isolated NB absence or hypoplasia compared with non-isolated NB absence or hypoplasia (98.4% vs. 91.7%, P =.028).

CONCLUSIONS

The residual risk of clinically significant CNVs in fetuses with NB absence or hypoplasia following the exclusion of theoretically NIPS-detectable findings was higher than that in low-risk pregnancies. This risk should be considered in genetic counseling to make a more comprehensive and precise choice regarding prenatal genetic testing.

The impact of implicit and explicit bias about disabilities on parent experiences and information provided during prenatal screening and testing

BACKGROUND

Prenatal screening technology has consistently raised concerns regarding the conversations and information provided about disabilities, particularly given that research shows trauma related to negative prenatal screening and diagnosis experiences among parents of children with Down syndrome.1 OBJECTIVE: To determine what information obstetric medical providers (OB/MFMs) are most and least likely to provide when delivering prenatal screening/testing results about Down syndrome (DS), the subsequent impact of bias on prenatal screening experiences, and how these issues can be addressed through training, resources, and professional guidelines.

METHODS

Online surveys were distributed to parents of children with DS born between 2016 and 2021 via local DS organizations and the national DS Diagnosis Network (April 2020-December 2021).

RESULTS

Of the 242 parents who completed the survey, a majority indicated that OB/MFMs were most likely to discuss medical issues and reproductive options while less than 40% reported that OB/MFMs discussed psychosocial outcomes, supports, and services. Respondents reported that the 61.3% of OB/MFMs who delivered the diagnosis as bad news or said "I'm sorry" were significantly less likely than their counterparts to provide information about life outcomes, supports and services, condition-specific resources, or more comprehensive prenatal care. Qualitative responses about screening/diagnosis experiences provided further context about the impact of implicit and explicit bias on the provision of accurate, up-to-date information.

CONCLUSION

To meet information needs during prenatal screening, OB/MFMs need access to accurate, balanced, and up-to-date information about disabilities and more training on disability cultural competency and how to deliver prenatal screening/testing results without implicit or explicit bias.

Human Genetics of Congenital Heart Defects

Congenital heart diseases (or congenital heart defects/disorders; CHDs) are structural abnormalities of the heart and/or great vessels that are present at birth. CHDs include an extensive range of defects that may be minor and require no intervention or may be life-limiting and require complex surgery shortly after birth. This chapter reviews the current knowledge on the genetic causes of CHD.

Genetic analysis of chorionic villus tissues in early missed abortions

Chromosomal abnormalities are the most common etiology of early spontaneous miscarriage. However, traditional karyotyping of chorionic villus samples (CVSs) is limited by cell culture and its low resolution. The objective of our study was to investigate the efficiency of molecular karyotyping technology for genetic diagnosis of early missed abortion tissues. Chromosome analysis of 1191 abortion CVSs in early pregnancy was conducted from August 2016 to June 2021; 463 cases were conducted via copy-number variations sequencing (CNV-seq)/quantitative fluorescent-polymerase chain reaction (QF-PCR) and 728 cases were conducted using SNP array. Clinically significant CNVs of CVSs were identified to clarify the cause of miscarriage and to guide the couples' subsequent pregnancies. Among these, 31 cases with significant maternal cell contamination were removed from the study. Among the remaining 1160 samples, 751 cases (64.7%) with genetic abnormalities were identified, of which, 531 (45.8%) were single aneuploidies, 31 (2.7%) were multiple aneuploidies, 50 (4.3%) were polyploidies, 54 (4.7%) were partial aneuploidies, 77 (6.6%) had submicroscopic CNVs (including 25 with clinically significant CNVs and 52 had variants of uncertain significance), and 8 cases (0.7%) were uniparental disomies. Our study suggests that both SNP array and CNV-seq/QF-PCR are reliable, robust, and high-resolution technologies for genetic diagnosis of miscarriage.

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).

Clinical Experience with Noninvasive Prenatal Testing in Twin Pregnancy Samples at a Single Center in Germany

In this study we wanted to determine the performance of a paired-end sequencing-based noninvasive prenatal testing (NIPT) assay in the detection of common fetal trisomies in twin pregnancy samples. Samples from patients with a twin pregnancy were collected from at least 10 weeks of gestation and analyzed at a single prenatal center in Germany. Results of Anomaly Detected (i.e., high risk) or No Anomaly Detected (i.e., low risk) for trisomy 21, trisomy 18, or trisomy 13 were reported. Follow-up confirmatory outcomes were requested for all cases. A total of 1,658 patients with twin pregnancies submitted samples during the study period; only two of these samples failed resulting in a low failure rate of 0.12%. Of the remaining 1,656 cases, there were 1,625 (98.1%) low-risk and 31 (1.9%) high-risk NIPT samples in our cohort. Of these, follow-up information was available for 301 (18.5%) of the low-risk samples and 19 (61.3%) of the high-risk samples. All of the low-risk cases with follow-up were determined to be true negatives giving an estimated negative predictive value of 100%. Seventeen of the 19 high-risk samples with follow-up were true positives, resulting in an overall positive predictive value of 89.5%. Sensitivities of > 99.9% were noted for both trisomy 21 and trisomy 18, with high specificities of ≥ 99.7% observed for all three trisomies. In conclusion, our study showed strong performance of the NIPT assay in the detection of common fetal trisomies in twin pregnancy samples, with high sensitivities, specificities, and positive predictive values observed based on known clinical outcomes along with a low failure rate.

Noninvasive prenatal screening with conventional sequencing depth to screen fetal copy number variants: A retrospective study of 19 144 pregnant women

AIM

To investigate the detectability of noninvasive prenatal screening (NIPS) with conventional sequencing depth to detect fetal copy number variants.

METHODS

We performed a retrospective study in a total of 19 144 pregnant women. Their cell-free plasma DNA were assessed for trisomy 21, trisomy 18, trisomy 13, sex chromosome aneuploidies, and genome-wide copy number variants by NIPS at conventional sequencing depth.

RESULTS

Three hundred seventy-four cases (2.0%, 374/19 144) with abnormal results were detected, which including 84 cases (0.4%, 84/19 144) with high risk of trisomy 21, 18, and 13, 90 cases (0.5%, 90/19 144) with high risk of sex chromosome abnormalities (SCA), and 44 cases (0.2%, 44/19 144) with high risk of other chromosome aneuploidies. One hundred fifty-six cases (0.8%, 156/19 144) with high risk of copy number variations (CNVs) were also detected. In following prenatal diagnosis, composite positive predictive value (PPV) of trisomy 21, 18, and 13 was 69.6% (48/69). The PPV of SCAs was 37.3% (19/51). And the PPVs for CNVs was detected as 51.0% (<5 Mb), 71.4% (5 Mb ≤ CNV ≤10 Mb), 56.5% (>10 Mb). Finally, a follow-up about the pregnancy outcomes were conducted for all available cases.

CONCLUSIONS

NIPS yielded high PPVs for trisomy 21, 18, and 13 aneuploidies and moderate PPVs for SCAs and CNVs. The screening effectiveness was closely related to the size of CNV fragments. Larger CNVs, especially larger than 5 Mb, could be detected more accurately by NIPS in our analytic technique. Meanwhile, diagnostic confirmation by microarray analysis was highly recommended.

High prevalence of maternal mosaic monosomy X in pregnant women in Vietnam

OBJECTIVE

To demonstrate the prevalence of maternal mosaic monosomy X (MMXO) in a cohort of pregnant women in Vietnam.

METHODS

All 105,594 singleton pregnant women undergoing noninvasive prenatal screening (NIPS) between January 2019 and February 2021 in Vietnam were analyzed by measuring discordance between size- and count-based z-scores for chromosome X (ChrX) to identify suspected cases of MMXO and validated by fluorescence in situ hybridization (FISH) on maternal blood.

RESULTS

We identified 295 (0.279%) suspected MMXO cases. After FISH analysis, MMXO was confirmed in 125 cases (42.37%), revealing the MMXO prevalence of 0.118% (95% CI: 0.097-0.139%) in this cohort.

CONCLUSION

We found a relatively high prevalence of MMXO in Vietnamese pregnant women and demonstrated a strong influence of MMXO on the ChrX z-score using a count-based method, resulting in false positives. The size-based method is not sensitive to MMXO and therefore achieves higher PPV.

Clinically Relevant Genetic Considerations for Patients With Tetralogy of Fallot

Genetic changes affect embryogenesis, cardiac and extracardiac phenotype, development, later onset conditions, and both short- and long-term outcomes and comorbidities in the increasing population of individuals with tetralogy of Fallot (TOF). In this review, we focus on current knowledge about clinically relevant genetics for patients with TOF across the lifespan. The latest findings for TOF genetics that are pertinent to day-to-day practice and lifelong management are highlighted: morbidity/mortality, cardiac/extracardiac features, including neurodevelopmental expression, and recent changes to prenatal screening and diagnostics. Genome-wide microarray is the first-line clinical genetic test for TOF across the lifespan, detecting relevant structural changes including the most common for TOF, the 22q11.2 microdeletion. Accumulating evidence illustrates opportunities for advances in understanding and care that may arise from genetic diagnosis at any age. We also glimpse into the near future when the multigenic nature of TOF will be more fully revealed, further enhancing possibilities for preventive care. Precision medicine is nigh.

Evaluation of pre-test counselling offered for non-invasive prenatal testing (NIPT) as a primary screening tool

The increasing popularity and expansion of non-invasive prenatal testing (NIPT) to screen for rare conditions beyond common trisomies prompts evaluation of pre-test counselling currently offered. We conducted a prospective survey to assess women's knowledge of NIPT in those who had undergone NIPT (study group) and those who were planning to have NIPT (control group). Out of the 189 questionnaires analysed, the study group did not show a higher knowledge score compared to the control group (P = 0.097). 44% misunderstood that NIPT can identify more conditions than invasive testing, 69.8% were unaware of the recommended need for nuchal translucency measurement and 52.6% were unaware of the possibility of incidental findings. 31% even considered discussing termination of pregnancy as one of the next steps if NIPT shows high risk for Down syndrome. This study shows that current pre-test counselling is inadequate. Service providers should address these knowledge gaps and assist women to make informed choices.Impact StatementWhat is already known on this subject? Pre-test counselling for non-invasive prenatal testing (NIPT) should be conducted to assist women in making an informed consent.What do the results of this study add? Our results show that a significant proportion of women are unaware of the limitations of NIPT.What are the implications of these findings for clinical practice and/or further research? Service providers should improve their pre-test counselling focusing on areas of knowledge deficiencies and misunderstanding on NIPT identified in this study.

High sensitivity and specificity in fetal gender identification in the first trimester, using ultrasound and Noninvasive Prenatal Screening (NIPS) in twin pregnancies, a prospective study

INTRODUCTION

Determination of the fetal gender in the first trimester is important in twin pregnancy cases of familial X-linked genetic syndromes and helps determine chorionicity. We assessed and compared the accuracy of first-trimester ultrasound scans, and cell-free fetal DNA (CfDNA) in determining fetal gender in the first trimester of twin pregnancies.

METHODS

Women with twin pregnancies were recruited prospectively during the first trimester. Fetal gender was determined using both ultrasound scans and CfDNA screening. Both results were compared to the newborn gender after delivery.

RESULTS

A total of 113 women with twin pregnancies were enrolled. There was 100% sensitivity and specificity in Y chromosome detection using CfDNA. Gender assignment using ultrasound in any first-trimester scans was 79.7%. Accuracy level increased from 54.2% in CRL 45-54 mm to 87.7% in CRL 55-67 mm and 91.5% in CRL 67-87 mm. Male fetuses had significantly higher chances of a gender assignment error compared to female fetuses, odds ratio = 23.574 (CI 7.346 - 75.656).

CONCLUSIONS

CfDNA is highly sensitive and specific in determining the presence of the Y chromosome in twin pregnancies in the first trimester. Between CRL 55-87 mm, ultrasound scanning offers a highly accurate determination of fetal gender in twin pregnancies.

Non-invasive prenatal testing (NIPT): is routinization problematic?

BACKGROUND

The introduction and wide application of non-invasive prenatal testing (NIPT) has triggered further evolution of routines in the practice of prenatal diagnosis. 'Routinization' of prenatal diagnosis however has been associated with hampered informed choice and eugenic attitudes or outcomes. It is viewed, at least in some countries, with great suspicion in both bioethics and public discourse. However, it is a heterogeneous phenomenon that needs to be scrutinized in the wider context of social practices of reproductive genetics. In different countries with their different regulatory frameworks, different patterns of routines emerge that have different ethical implications. This paper discusses an ethics of routines informed by the perspectives of organizational sociology and psychology, where a routine is defined as a repetitive, recognizable pattern of interdependent organizational actions that is carried out by multiple performers. We favour a process approach that debunks the view - which gives way to most of the concerns - that routines are always blindly performed. If this is so, routines are therefore not necessarily incompatible with responsible decision-making. Free and informed decision-making can, as we argue, be a key criterion for the ethical evaluation of testing routines. If free and informed decision-making by each pregnant woman is the objective, routines in prenatal testing may not be ethically problematic, but rather are defensible and helpful. We compare recent experiences of NIPT routines in the context of prenatal screening programmes in Germany, Israel and the Netherlands. Notable variation can be observed between these three countries (i) in the levels of routinization around NIPT, (ii) in the scope of routinization, and (iii) in public attitudes toward routinized prenatal testing.

CONCLUSION

An ethics of routines in the field of prenatal diagnostics should incorporate and work with the necessary distinctions between levels and forms of routines, in order to develop sound criteria for their evaluation.

Understanding knowledge, perception, and willingness of non-invasive prenatal testing for fetal aneuploidy: a survey among Chinese high-risk pregnant women

Objectives

Non-invasive prenatal testing (NIPT) is utilized for screening the likelihood of fetal aneuploidy, presenting the benefits of non-invasiveness, high sensitivity, and specificity. Its application in prenatal screening has become ubiquitous. The inquiry into how pregnant women comprehend and determine NIPT screening strategies is paramount. Regrettably, there has been a dearth of research on this subject in China. Consequently, this study scrutinizes pregnant women's cognizance and perspectives concerning NIPT, furnishing a foundation for advancing its judicious implementation.

Methods

From February 2021 to December 2022, a questionnaire survey was conducted among pregnant women receiving prenatal care and screening at the Women's Hospital, School of Medicine, Zhejiang University, who were randomly selected from a pool of individuals exhibiting a high risk of fetal aneuploidy on serological screening. The survey aimed to gather data on participant characteristics, knowledge, perception, and willingness concerning NIPT. The study employed chi-square and Kruskal Wallis tests to analyze subgroup differences.

Results

A total of 226 valid questionnaires were obtained. 83.2% of women pregnant women identified as high risk by serological screening would opt for NIPT, with 66.4% indicating that they would prefer NIPT for fetal aneuploidy screening in future pregnancies. These findings suggest a notable willingness among pregnant women to undergo NIPT. Additionally, the results suggest that various factors, including place of residence, educational level, family income, causes of abortion, and conception method, influence pregnant women's knowledge about NIPT Accordingly, the level of NIPT knowledge varies among pregnant women.

Conclusion

The survey generally revealed that pregnant women were strongly inclined to select NIPT; however, expectant Chinese mothers possess limited knowledge and perception regarding this screening method for fetal aneuploidy. Therefore, the government must implement effective measures to augment public awareness of fetal aneuploidy screening and encourage the judicious utilization of NIPT.

Ethical concerns surrounding sex prediction using noninvasive prenatal screening from pediatric endocrinologists' perspective

Noninvasive prenatal screening (NIPS) with predicted fetal sex chromosomes included in the results has become increasingly available for pregnant individuals. Predicted fetal sex chromosome results from NIPS are interpreted so as to equate sex chromosomes with sex and gender. As pediatric endocrinologists, we worry about how this use of NIPS harmfully reinforces sex and gender binaries and sets potentially inaccurate assumptions about what the identified chromosomes mean. We use a hypothetical case based on our clinical experience in which the NIPS report of fetal sex does not conform to expectations at birth to highlight ethical concerns surrounding this practice. The use of NIPS for fetal sex chromosome prediction has the potential to perpetuate stigma and bring psychological harm to parents and their future children, particularly those who are intersex, transgender, and gender diverse. The medical community should adopt an approach to the use of NIPS for fetal sex chromosome prediction that recognizes the spectrums of sex and gender to avoid reproducing stigma towards sex- and gender-diverse individuals and associated harms.

Panels, Exomes, Genomes, and More-Finding the Best Path Through the Diagnostic Odyssey

Selecting the ideal test to evaluate an individual with a suspected genetic disorder can be challenging. While several clinical testing options are available, no single test yet captures all potentially causative genetic variants. Thus, clinicians may order testing in a stepwise fashion, and what to order after non-diagnostic testing can be challenging to determine. Here, we provide an overview of commonly used clinical genetic tests, guidance on when they are best used, and what they may miss. We conclude with a discussion of how new technologies might be used to identify challenging variants and simplify clinical testing in the future.

Preliminary study of noninvasive prenatal screening for 22q11.2 deletion/duplication syndrome using multiplex dPCR assay

OBJECTIVE

This study aimed to establish a cell-free fetal DNA (cffDNA) assay using multiplex digital PCR (dPCR) for identifying fetuses at increased risk of 22q11.2 deletion/duplication syndrome.

METHODS

Six detection sites and their corresponding probes were designed for the 22q11.2 recurrent region. A dPCR assay for the noninvasive screening of 22q11.2 deletion/duplication syndrome was established. A total of 130 plasma samples from pregnant women (including 15 samples with fetal 22q11.2 deletion/duplication syndrome) were blindly tested for evaluating the sensitivity and specificity of the established assay.

RESULTS

DNA with different sizes of 22q11.2 deletion/duplication was detected via dPCR, indicating that the designed probes and detection sites were reasonable and effective. In the retrospective clinical samples, 11 out of 15 samples of pregnant women with 22q11.2 deletion/duplication were detected during the cffDNA assay, and accurate regional localization was achieved. Among the 115 normal samples, 111 were confirmed to be normal. Receiver operating characteristic curves were used for assessing the cut-off values and AUC for these samples. The sensitivity, specificity, and positive as well as negative predictive values were 73.3%, 96.5%, 73.3%, and 96.5%, respectively.

CONCLUSION

The cffDNA assay based on dPCR technology for the noninvasive detection of 22q11.2 recurrent copy number variants in fetuses detected most affected cases, including smaller but relatively common nested deletions, with a low false-positive rate. It is a potential, efficient and simple method for the noninvasive screening of 22q11.2 deletion/duplication syndrome.

Navigation of Prenatal Care With Sex Discordance Between Cell-free DNA and Ultrasound Findings

The utilization of cell-free DNA (cfDNA) screening has expanded rapidly across the age spectrum of pregnant persons. With cfDNA's widespread adoption, genetic fetal sex is now often known before a phenotypic assessment on anatomic survey. CfDNA detects sex discordance in 1/1500 to 2000 pregnancies. Upon detection of sex discordance, lab error or other factors should first be assessed. Once other causes have been ruled out, this may indicate an underlying disorder/difference in sex development. A multidisciplinary team should coordinate diagnosis, treatment, and support for the family. This review discusses the diagnostic workup, emphasizing the multidisciplinary counseling and management of disorder/differences in sex development.

Obstetrical, perinatal, and genetic outcomes associated with nonreportable prenatal cell-free DNA screening results

BACKGROUND

The clinical implications of nonreportable cell-free DNA screening results are uncertain, but such results may indicate poor placental implantation in some cases and be associated with adverse obstetrical and perinatal outcomes.

OBJECTIVE

This study aimed to assess the outcomes of pregnancies with nonreportable cell-free DNA screening in a cohort of patients with complete genetic and obstetrical outcomes.

STUDY DESIGN

This was a prespecified secondary analysis of a multicenter prospective observational study of prenatal cell-free DNA screening for fetal aneuploidy and 22q11.2 deletion syndrome. Participants who underwent cell-free DNA screening from April 2015 through January 2019 were offered participation. Obstetrical outcomes and neonatal genetic testing results were collected from 21 primary-care and referral centers in the United States, Europe, and Australia. The primary outcome was risk for adverse obstetrical and perinatal outcomes (aneuploidy, preterm birth at <28, <34, and <37 weeks' gestation, preeclampsia, small for gestational age or birthweight <10th percentile for gestational week, and a composite outcome that included preterm birth at <37 weeks, preeclampsia, small for gestational age, and stillbirth at >20 weeks) after nonreportable cell-free DNA screening because of low fetal fraction or other causes. Multivariable analyses were performed, adjusting for variables known to be associated with obstetrical and perinatal outcomes, nonreportable results, or fetal fraction.

RESULTS

In total, 25,199 pregnant individuals were screened, and 20,194 were enrolled. Genetic confirmation was missing in 1165 (5.8%), 1085 (5.4%) were lost to follow-up, and 93 (0.5%) withdrew; the final study cohort included 17,851 (88.4%) participants who had cell-free DNA, fetal or newborn genetic confirmatory testing, and obstetrical and perinatal outcomes collected. Results were nonreportable in 602 (3.4%) participants. A sample was redrawn and testing attempted again in 427; in 112 (26.2%) participants, results were again nonreportable. Nonreportable results were associated with higher body mass index, chronic hypertension, later gestational age, lower fetal fraction, and Black race. Trisomy 13, 18, or 21 was confirmed in 1.6% with nonreportable tests vs 0.7% with reported results (P=.013). Rates of preterm birth at <28, 34, and 37 weeks, preeclampsia, and the composite outcome were higher among participants with nonreportable results, and further increased among those with a second nonreportable test, whereas the rate of small for gestational age infants was not increased. After adjustment for confounders, the adjusted odds ratios were 2.2 (95% confidence interval, 1.1-4.4) and 2.6 (95% confidence interval, 0.6-10.8) for aneuploidy, and 1.5 (95% confidence interval, 1.2-1.8) and 2.1 (95% confidence interval, 1.4-3.2) for the composite outcome after a first and second nonreportable test, respectively. Of the patients with nonreportable tests, 94.9% had a live birth, as opposed to 98.8% of those with reported test results (adjusted odds ratio for livebirth, 0.20 [95% confidence interval, 0.13-0.30]).

CONCLUSION

Patients with nonreportable cell-free DNA results are at increased risk for a number of adverse outcomes, including aneuploidy, preeclampsia, and preterm birth. They should be offered diagnostic genetic testing, and clinicians should be aware of the increased risk of pregnancy complications.

Performance of noninvasive prenatal testing for twin pregnancies in South China

OBJECTIVE

The purpose of this study was to evaluate the performance of noninvasive prenatal testing (NIPT) for the detection of chromosomal aneuploidies and copy number variations (CNVs) in twin pregnancies.

METHOD

A cohort of 2010 women with twin pregnancies was recruited. 1331 patients opted for NIPT, and 679 patients opted for expanded NIPT (NIPT-plus). All high-risk patients were advised to undergo invasive prenatal diagnosis. All participants were followed up until 6 months after birth.

RESULTS

Twenty-two cases were predicted to have a high risk of chromosome abnormalities by NIPT, of which 14 pregnant women underwent invasive prenatal diagnosis. The 14 cases included 3 cases of trisomy 21, 1 case of trisomy 18, 1 case of trisomy 7, 2 cases of sex chromosome aneuploidies (SCAs), and 7 cases of CNVs, of which the confirmed cases numbered 2, 1, 0, 1, and 0, respectively. Twenty cases were predicted to have a high risk of chromosome abnormalities by NIPT-plus, of which 16 pregnant women underwent invasive prenatal diagnosis. The 16 cases included 1 case of trisomy 21, 1 case of trisomy 7, 7 cases of SCAs, and 7 cases of CNVs, of which were confirmed in 1, 0, 3, and 2, respectively. No false-negative result was reported during the follow-up period.

CONCLUSION

The NIPT/NIPT-plus has excellent performance in the detection of chromosome aneuploidies in twin pregnancies. But for CNVs, the effectiveness of NIPT is poor, and the NIPT-plus have a certain detection efficiency. It is worth noting that pre- and post-genetic counseling is especially important, and the chorionicity, mode of conception, clinical indications, and fetal fraction should be considered as influencing factors.

Analysis of retest reliability for pregnant women undergoing cfDNA testing with a no-call result

BACKGROUND

Determining the reasons for unreportable or no-call cell-free DNA (cfDNA) test results has been an ongoing issue, and a consensus on subsequent management is still lacking. This study aimed to explore potential factors related to no-call cfDNA test results and to discuss whether retest results are reliable.

METHODS AND RESULTS

This was a retrospective study of women with singleton pregnancies undergoing cfDNA testing in 2021. Of the 9871 pregnant patients undergoing cfDNA testing, 111 had a no-call result, and their results were compared to those of 170 control patients. The no-call rate was 1.12% (111/9871), and the primary cause for no-call results was data fluctuation (88.29%, 98/111). Medical conditions were significantly more frequent in the no-call group than in the reportable results group (P < 0.001). After retesting, 107 (107/111, 96.40%) patients had a result, and the false-positive rate (FPR) of retesting was 10.09% (10.09%, 11/109). In addition, placental lesions were more frequent in the no-call group than in the reportable results group (P = 0.037), and 4 patients, all in the no-call group, experienced pregnancy loss.

CONCLUSIONS

Pregnant women with medical conditions are more likely to have a no-call result. A retest is suggested for patients with a no-call result, but retests have a high FPR. In addition, pregnant women with a no-call result are at increased risk of adverse pregnancy outcomes. In conclusion, more attention should be given to pregnant women for whom a no-call cfDNA result is obtained.

Non-invasive prenatal test findings in 41,819 pregnant women: results from a clinical laboratory in southern China

BACKGROUND

This paper evaluated the clinical utility of massively parallel sequencing-based non-invasive prenatal testing (NIPT) for detecting trisomy 21 (T21), T18, T13, sex chromosome aneuploidies (SCA), and rare chromosome aneuploidies (RCA) among the data collected by a clinical laboratory in southern China.

METHODS

In a 3-year period between January 2017 and December 2019, over 40,000 pregnant women underwent NIPT clinical screening test for fetal T21, T18, T13, SCA, and RCA in our laboratory. NIPT samples were processed using the NextSeq CN500 platform. The positive results were confirmed by karyotyping, and chromosomal microarray analysis (CMA) or copy number variants (CNV) sequencing. Details of the pregnancy outcomes were collected via telephone interview.

RESULTS

NIPT results were available for 41,819 cases; 691 positive cases were reported. The overall sensitivity for detection of T21, T18, T13, SCA, and RCA was 99.21, 100.00, 100.00, 98.55, and 100.00%, and the specificity was 99.95, 99.94, 99.98, 99.69, and 99.92%, respectively. The positive predictive values (PPVs) for detection of T21, T18, T13, SCA, and RCA were 85.62, 45.24, 40.00, 34.17, and 13.51%, respectively, and those for detection of 45,X, 47,XXY, 47,XXX, 47,XYY, and 46,XY(delX) 20.00, 59.18, 28.95, 61.54, and 25.00%, respectively. Regarding pregnancy outcomes, 92.38% of the pregnancies with confirmed aneuploidies were terminated, and 91.20% of those identified as having a false-positive result were carried to term. Among 252 unconfirmed cases, 24.60% of the pregnancies were terminated and 38.10% carried to term, while 37.30% declined interview.

CONCLUSIONS

NIPT is widely used to screen fetal aneuploidies based on its high sensitivity and specificity. However, in this study, the PPVs of NIPT in terms of detecting T18, T13, XO, XXX and RCA were < 50%. In addition, more than one-third of NIPT-positive women did not accept invasive prenatal diagnosis. Confirmatory diagnosis is strongly recommended for women with positive NIPT outcomes before any further decision is made.

Evaluation of the clinical effects of non-invasive prenatal screening for diseases associated with aneuploidy and copy number variation

BACKGROUND

To explore and compare the clinical effects of high-resolution non-invasive prenatal screening (NIPS-Plus) for common/uncommon chromosomal aneuploidy and microdeletion/microduplication syndromes (MMS).

METHODS

The current prospective study included a total of 25,380 pregnant women who performed NIPS-Plus, and amniocentesis was performed on women with MMS with the screening results to diagnose patients with suspected MMS.

RESULTS

There were 415 samples with positive results for NIPS-Plus, included 275 with aneuploidy and 140 with MMS. After diagnosis by amniocentesis, 188 cases were confirmed as true positive, included46 cases of T21, 9 cases of T18, 1 case of T13, 34 cases of SCA, 41 cases of other chromosomal euploidy and 57 cases of MMS. In addition, no false negative cases were found, MMS was classified with 5 Mb with the cutoff value, and the PPV of different fragment size was counted, respectively.

CONCLUSION

We found that the corresponding PPV was 44.66% with the fragment of copy number variation (CNV) being less than or equal to 5 Mb, and when it was greater than 5 Mb, the PPV was 29.73%, which suggested that NIPS-Plus was more suitable for screening the PPV of small fragment abnormalities. NIPS-Plus has a good application effect in routine aneuploidy screening and had the best detection effect for T21; moreover, it performed well in screening of MMS and had better detection effect on MMS with CNV fragment length less than 5 Mb. Based on the current results, we suggested that NIPS-Plus should be used as a comprehensive elementary prenatal screening method for all pregnant women, but for MMS caused by abnormal large fragment CNV, the detection method and efficiency still need to be improved.

Differences of Sex Development: Current Issues and Controversies

Differences of sex development (DSD) encompass a broad range of conditions in which the development of chromosomal, gonadal, or anatomic sex is not typically male or female. Terms used to describe DSD are controversial, and continuously evolving. An individualized, multidisciplinary approach is key to both the diagnosis and management of DSD. Recent advances in DSD care include expanded genetic testing options, a more nuanced approach to gonadal management, and an emphasis on shared decision-making, particularly related to external genital surgical procedures. The timing of DSD surgery is currently being questioned and debated in both medical and advocacy/activism spheres.

Evaluation of noninvasive prenatal screening for copy number variations among screening laboratories

OBJECTIVE

To evaluate the current situation of expanded noninvasive prenatal screening (NIPS) for copy number variations (CNVs) in laboratories in China, the National Center of Clinical Laboratories conducted an externalqualityassessment (EQA) program.

METHODS

The EQA panel consisted of 12 artificial samples associated with different syndromes, which were mixed with maternal plasma collected from pregnant women and enzyme-digested cell-free DNA (cfDNA) from cell lines with different fetal fractions (FFs) ranging from 5% to 15%. The panel was validated by next-generation sequencing and distributed to laboratories, along with questionnaires and case scenarios.

RESULTS

Sixty-nine laboratories participated in the EQA program, and 91.30% (63/69) of laboratories correctly identified all samples. A total of 7.25% (5/69) of the laboratories reported false-negative results, and 2.90% (2/69) of the laboratories reported unexpected CNVs. The correct rates of the 22q11.2 deletion syndrome, Cri-du-chat syndrome, 1p36 deletion syndrome and Angelman/Prader-Willi syndrome samples were 97.46%, 98.55%, 100%, and 100%, respectively. With the increase in the FF, deletion size, and read depth, the detection rate increased. For results reports, only five laboratories reported FF values, one laboratory reported the CNV classification type, and none reported sensitivity, specificity, positive predictive values, and negative predictive values.

CONCLUSION

The detection capabilities of NIPS for CNVs still need to be improved and standardized, and FF, deletion size, and read depth are factors that affect the detection rate.

Analysis of human invasive cytotrophoblasts demonstrates mosaic aneuploidy

A total of 24 chromosome-specific fluorescence in situ hybridization probes for interphase nucleus analysis were developed to determine the chromosomal content of individual human invasive cytotrophoblasts derived from in vitro cultured assays. At least 75% of invasive cytotrophoblasts were hyperdiploid and the total number of chromosomes ranged from 47 to 61. The results also demonstrated that these hyperdiploid invasive cytotrophoblasts showed significant heterogeneity. The most copy number gains were observed for chromosomes 13, 14, 15, 19, 21, and 22 with average copy number greater than 2.3. A parallel study using primary invasive cytotrophoblasts also showed a similar trend of copy number changes. Conclusively, 24-chromosome analysis of human non-proliferating cytotrophoblasts (interphase nuclei) was achieved. Hyperdiploidy and chromosomal heterogeneity without endoduplication in invasive cytotrophoblasts may suggest a selective advantage for invasion and short lifespan during normal placental development.

Prenatal diagnosis in a fetuses with a clenched hands, overlapping fingers, and clubfoot due to MED12 deficiency in three affected siblings: A case report

A fetal clenched hand with overlapping fingers is more common in aneuploidy syndrome and was not well-documented in MED12 deficiency. This study reports the clinical and genetic findings of three affected siblings from a Chinese family. The chromosome karyotype analysis diagram shows that karyotypes of the three children were normal. Trio whole-exome sequencing and Sanger sequencing verification found that there was a MED12 R296Q variant in normal mothers and their two offspring. A pattern of clenched hand with overlapping fingers (clinodactyly) and clubfoot was found in all the three affected siblings by three-dimensional ultrasound. The discovery of this case shows that even if the chromosome karyotype is normal, comprehensive prenatal genetic diagnosis is required when the ultrasound results show a clenched hand with clinodactyly and clubfoot symptoms.

The predictive value of noninvasive prenatal screening for copy number variations: a cohort study and a systematic meta-analysis

OBJECTIVE

To assess the diagnostic accuracy of noninvasive prenatal screening (NIPS) in screening for copy number variations (CNVs).

METHODS

We conducted a systematic review and meta-analysis by combining our study results with those reported in other articles. We retrospectively collected the data of pregnant women with NIPS testing in the Hangzhou Women's Hospital from December 2019 to February 2022. Simultaneously, a systematic search of PubMed, EMBASE, and Web of Science was carried out to identify all relevant peer-reviewed publications. Statistical analysis was performed based on the random-effects model to determine a pooled estimate of the positive predictive value (PPV).

RESULTS

A total of 29 studies involving 2,667 women were included for analysis. The pooled PPV of NIPS in the detection of CNVs was 32.86% (95% confidence interval [24.61-41.64]). Statistical heterogeneity was high, while no significant publication bias was found in this meta-analysis. There were insufficient data to accurately determine sensitivity and specificity, as most studies only performed confirmatory tests on high-risk women.

CONCLUSIONS

The PPV of NIPS in screening for CNVs was approximately 33%. Cautions should be kept in mind for the pretest guidance and subsequent after-test counseling when offering such genome-wide NIPS tests.

Laboratory performance of genome-wide cfDNA for copy number variants as compared to prenatal microarray

BACKGROUND

Noninvasive prenatal testing (NIPT) allows for screening of fetal aneuploidy and copy number variants (CNVs) from cell-free DNA (cfDNA) in maternal plasma. Professional societies have not yet embraced NIPT for fetal CNVs, citing a need for additional performance data. A clinically available genome-wide cfDNA test screens for fetal aneuploidy and CNVs larger than 7 megabases (Mb).

RESULTS

This study reviews 701 pregnancies with "high risk" indications for fetal aneuploidy which underwent both genome-wide cfDNA and prenatal microarray. For aneuploidies and CNVs considered 'in-scope' for the cfDNA test (CNVs ≥ 7 Mb and select microdeletions), sensitivity and specificity was 93.8% and 97.3% respectively, with positive and negative predictive values of 63.8% and 99.7% as compared to microarray. When including 'out-of-scope' CNVs on array as false negatives, the sensitivity of cfDNA falls to 48.3%. If only pathogenic out-of-scope CNVs are treated as false negatives, the sensitivity is 63.8%. Of the out-of-scope CNVs identified by array smaller than 7 Mb, 50% were classified as variants of uncertain significance (VUS), with an overall VUS rate in the study of 2.29%.

CONCLUSIONS

While microarray provides the most robust assessment of fetal CNVs, this study suggests that genome-wide cfDNA can reliably screen for large CNVs in a high-risk cohort. Informed consent and adequate pretest counseling are essential to ensuring patients understand the benefits and limitations of all prenatal testing and screening options.

Clinical Experience with Genome-Wide Noninvasive Prenatal Screening in a Large Cohort of Twin Pregnancies

Non-invasive prenatal screening (NIPS) in twin gestations has been shown to have high detection rates and low false-positive rates for trisomy 21, as seen in singleton pregnancies, although there have been few large cohort twin studies, genome-wide studies in particular, to date. In this study, we looked at the performance of genome-wide NIPT in a large cohort consisting of 1244 twin pregnancy samples collected over a two-year period in a single laboratory in Italy. All samples underwent an NIPS for common trisomies, with 61.5% of study participants choosing to undergo genome-wide NIPS for additional fetal anomalies (namely, rare autosomal aneuploidies and CNVs). There were nine initial no-call results, all of which were resolved upon retest. Based on our NIPS results, 17 samples were at high risk for trisomy 21, one for trisomy 18, six for a rare autosomal aneuploidy, and four for a CNV. Clinical follow-up was available for 27 out of 29 high-risk cases; a sensitivity of 100%, a specificity of 99.9%, and a PPV of 94.4% were noted for trisomy 21. Clinical follow-up was also available for 1110 (96.6%) of the low-risk cases, all of which were true negatives. In conclusion, we found that NIPS was a reliable screening approach for trisomy 21 in twin pregnancies.

Never "totally prepared": Support groups on helping families prepare for a child with a genetic condition

A rapid increase in the reach and breadth of prenatal genetic screening and testing has led to an expanding need for prenatal support of families receiving this genetic information. As part of a larger study investigating prenatal preparation for a child with a genetic condition, we interviewed representatives of patient advocacy groups (PAGs) who support parents post-diagnosis. Groups supporting families with Down syndrome were often local or regional, while other groups were often national or international in scope. Groups varied in their willingness or ability to support families prior to making a pregnancy continuation decision, and participants reflected on ways they addressed these needs with individual counseling and referrals, if needed. Participants described supporting parents with information about conditions and a range of lived experiences for families, while referring families to healthcare professionals for technical questions and additional medical needs. PAGs also prioritized connecting parents experiencing a new diagnosis with other families for peer support and community-building, both in person and on social media. Participants discussed limitations, such as a lack of racially-concordant support, ability to offer resources in languages other than English, and a lack of funding to meet the expressed needs of families post-diagnosis. Overall, participants emphasized that the parenting experience of each child is unique, irrespective of a genetic diagnosis, an experience for which parents can never be "totally prepared."

Clinical Validation and Diagnostic Utility of Optical Genome Mapping in Prenatal Diagnostic Testing

The standard-of-care diagnostic prenatal testing includes a combination of cytogenetic methods, such as karyotyping, fluorescence in situ hybridization (FISH), and chromosomal microarray (CMA), using either direct or cultured amniocytes or chorionic villi sampling. However, each technology has its limitations: karyotyping has a low resolution (>5 Mb), FISH is targeted, and CMA does not detect balanced structural variations (SVs). These limitations necessitate the use of multiple tests, either simultaneously or sequentially, to reach a genetic diagnosis. Optical genome mapping (OGM) is an emerging technology that can detect several classes of SVs in a single assay, but it has not been evaluated in the prenatal setting. This validation study analyzed 114 samples that were received in our laboratory for traditional cytogenetic analysis with karyotyping, FISH, and/or CMA. OGM was 100% concordant in identifying the 101 aberrations that included 29 interstitial/terminal deletions, 28 duplications, 26 aneuploidies, 6 absence of heterozygosity regions, 3 triploid genomes, 4 isochromosomes, and 1 translocation; and the method revealed the identity of 3 marker chromosomes and 1 chromosome with additional material not determined by karyotyping. In addition, OGM detected 64 additional clinically reportable SVs in 43 samples. OGM has a standardized laboratory workflow and reporting solution that can be adopted in routine clinical laboratories and demonstrates the potential to replace the current standard-of-care methods for prenatal diagnostic testing.

Clinical application of noninvasive prenatal testing in twin pregnancies: a single-center experience

OBJECTIVES

To evaluate the clinical efficiency of noninvasive prenatal testing (NIPT) for fetal chromosomal aneuploidy screening in twin pregnancies.

METHODS

A total of 1650 women with twin pregnancies were enrolled in the study, which underwent NIPT at the Southwest Hospital, Army Medical University, Chongqing, China from January 2013 to June 2022. Fetal karyotyping analysis was conducted in high-risk patients, with subsequent follow-up on pregnancy outcomes.

RESULTS

In 1650 pregnancies, NIPT results showed ten cases of the fetal chromosome aneuploidy, of which six cases were true positive and four cases were false positive. The sensitivity, specificity, positive predictive value (PPV), and false-positive rate (FPR) of trisomy 21 were 100%, 99.79%, 57.14%, and 0.18%, respectively. Sensitivity, specificity, PPV, and FPR of trisomy 18 were 100%, 99.94%, 50%, and 0.06%, respectively. The sensitivity, specificity, PPV, and FPR of trisomy 13 were 100%, 100%, 100%, and 0%, respectively. No false negatives were detected and the negative predictive value (NPV) was 100% of the total. Eleven pregnancies failed the NIPT test with no-call due to the low fetal fraction (< 4%).

CONCLUSIONS

NIPT is a high-performing routine primary prenatal screening test in twin pregnancies, with high sensitivity and specificity in screening for fetal aneuploidy.

The predictive value of prenatal cell-free DNA testing for rare autosomal trisomies: a systematic review and meta-analysis

OBJECTIVE

The diagnostic accuracy of cell-free fetal DNA in screening for rare autosomal trisomies is uncertain. We conducted a systematic review and meta-analysis aiming to determine the predictive value of cell-free DNA in screening for rare autosomal trisomies.

DATA SOURCES

PubMed, Embase, and Web of Science were searched from inception to January 2022.

STUDY ELIGIBILITY CRITERIA

All studies that reported on the diagnostic accuracy of cell-free DNA in the detection of rare autosomal trisomies were included. Case series were included if they contained at least 10 cases with diagnostic test results or postnatal genetic testing.

METHODS

Study appraisal was completed using the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) tool. Statistical analysis was performed using random-effects meta-analysis of double-arcsine transformed proportions of confirmed results in the fetus out of the positive tests to obtain a pooled estimate of the positive predictive value.

RESULTS

The search identified 7553 studies, of which 1852 were duplicates. After screening 5701 titles and abstracts, 380 studies proceeded to the full-text screen; 206 articles were retrieved for data extraction, of which another 175 articles were excluded. A total of 31 studies, with a total of 1703 women were included for analysis. The pooled positive predictive value of cell-free DNA for the diagnosis of rare autosomal trisomies was 11.46% (95% confidence interval, 7.80-15.65). Statistical heterogeneity was high (I²=82%). Sensitivity analysis restricted to 5 studies at low risk of bias demonstrated a pooled positive predictive value of 9.13% (95% confidence interval, 2.49-18.76). There were insufficient data to provide accurate ascertainment of sensitivity and specificity because most studies only offered confirmatory tests to women with high-risk results.

CONCLUSION

The positive predictive value of cell-free DNA in diagnosing rare autosomal trisomies is approximately 11%. Clinicians should provide this information when offering cell-free DNA for screening of conditions outside of common autosomal trisomies.

Deep phenotypic analysis of psychiatric features in genetically defined cohorts: application to XYY syndrome

BACKGROUND

Recurrent gene dosage disorders impart substantial risk for psychopathology. Yet, understanding that risk is hampered by complex presentations that challenge classical diagnostic systems. Here, we present a suite of generalizable analytic approaches for parsing this clinical complexity, which we illustrate through application to XYY syndrome.

METHOD

We gathered high-dimensional measures of psychopathology in 64 XYY individuals and 60 XY controls, plus additional interviewer-based diagnostic data in the XYY group. We provide the first comprehensive diagnostic description of psychiatric morbidity in XYY syndrome and show how diagnostic morbidity relates to functioning, subthreshold symptoms, and ascertainment bias. We then map behavioral vulnerabilities and resilience across 67 behavioral dimensions before borrowing techniques from network science to resolve the mesoscale architecture of these dimensions and links to observable functional outcomes.

RESULTS

Carriage of an extra Y-chromosome increases risk for diverse psychiatric diagnoses, with clinically impactful subthreshold symptomatology. Highest rates are seen for neurodevelopmental and affective disorders. A lower bound of < 25% of carriers are free of any diagnosis. Dimensional analysis of 67 scales details the profile of psychopathology in XYY, which survives control for ascertainment bias, specifies attentional and social domains as the most impacted, and refutes stigmatizing historical associations between XYY and violence. Network modeling compresses all measured symptom scales into 8 modules with dissociable links to cognitive ability, adaptive function, and caregiver strain. Hub modules offer efficient proxies for the full symptom network.

CONCLUSIONS

This study parses the complex behavioral phenotype of XYY syndrome by applying new and generalizable analytic approaches for analysis of deep-phenotypic psychiatric data in neurogenetic disorders.

Timing of Referrals to a Down Syndrome Parent Group by Race

The Down Syndrome Association of Central Ohio (DSACO) is a nonprofit organization that supports families, promotes community involvement, and encourages lifetime opportunities for people with Down syndrome.

Methods

At DSACO, ongoing efforts for quality improvement included: a Medical Advisory Committee in 2016, the creation of resources groups for Latino families in 2017, for Somali families from 2018 to 2019, and for African American families in fall 2018, presentations at birth hospitals, and close tracking of referrals from hospitals when an infant with Down syndrome is born. In addition, the timing of referrals, either "early" (on the day of birth or the first day after birth) or "late" (2 or more days after birth), were tracked and plotted in p charts.

Results

From January 2017 to April 2021, DSACO received 167 referrals; of these, a median of 65% was received "early." When analyzing all referrals to DSACO, no special cause was seen over the time studied. When evaluating the timing of referral to DSACO by race, referrals for 78% of White families were early (105/135 referrals). In comparison, referrals for 9% of minority families were early (3/32 referrals).

Conclusions

The timing of DSACO referral differed by race. Outreach efforts did not change referral timing but led to a more diverse DSACO membership. Future study is needed to confirm if there is racial disparity in the timing of referrals to resources nationally and to understand the barriers in referring diverse families to Down syndrome nonprofit organizations.

Noninvasive prenatal screening (NIPS) for fetal chromosome abnormalities in a general-risk population: An evidence-based clinical guideline of the American College of Medical Genetics and Genomics (ACMG)

PURPOSE

This workgroup aimed to develop an evidence-based clinical practice guideline for the use of noninvasive prenatal screening (NIPS) for pregnant individuals at general risk for fetal trisomy 21, trisomy 18, or trisomy 13 and to evaluate the utility of NIPS for other chromosomal disorders.

METHODS

The NIPS Evidence-Based Guideline Work Group (n = 7) relied on the results from the recent American College of Medical Genetics and Genomics (ACMG) systematic review to form the evidentiary basis of this guideline. Workgroup members used the Grading of Recommendations Assessment, Development, and Evaluation Evidence to Decision framework to draft recommendations. The guideline underwent extensive internal and external peer review with a public comment period before approval by the ACMG Board of Directors.

RESULTS

Evidence consistently demonstrated improved accuracy of NIPS compared with traditional screening methods for trisomies 21, 18, and 13 in singleton and twin gestations. Identification of rare autosomal trisomies and other microdeletion syndromes with NIPS is an emerging area of interest.

CONCLUSION

ACMG strongly recommends NIPS over traditional screening methods for all pregnant patients with singleton and twin gestations for fetal trisomies 21, 18, and 13 and strongly recommends NIPS be offered to patients to screen for fetal sex chromosome aneuploidy.

Performance of a cell-free DNA prenatal screening test, choice of prenatal procedure, and chromosome conditions identified during pregnancy after low-risk cell-free DNA screening

OBJECTIVES

To evaluate the performance of cell-free DNA (cfDNA) screening for common fetal aneuploidies, choice of prenatal procedure, and chromosome conditions identified during pregnancy after low-risk cfDNA screening.

METHOD

A single-center prenatal cfDNA screening test was employed to detect trisomies 21, 18, and 13 (T21, T18, T13) and sex chromosome aneuploidies (SCAs). Test performance, choice of prenatal procedure, and cytogenetic results in pregnancies with low-risk cfDNA screening were reviewed.

RESULTS

CfDNA screening of 38,289 consecutive samples identified 720 (1.9%) pregnancies at increased risk for aneuploidy. Positive predictive values (PPVs) for high-risk singleton pregnancies were 98.5% (T21), 92.5% (T18) and 55.2% (T13). PPVs for SCAs ranged from 30.6% to 95.2%. Most women elected chorionic villus sampling for prenatal diagnosis of T21, T18 and T13; amniocentesis and/or postnatal testing were commonly chosen for SCAs. Cytogenetic tests from 616 screen-negative pregnancies identified 64 cases (12.7%) with chromosome conditions not detected by cfDNA screening, including triploidy (n = 30) and pathogenic and likely pathogenic copy number variants (n = 34). A further 15 (0.04%) false-negative common aneuploidy results were identified.

CONCLUSIONS

CfDNA screening was highly accurate for detecting fetal aneuploidy in this general-risk obstetric population. Fetal ultrasound and prenatal diagnostic testing were important in identifying chromosome conditions in pregnancies screened as low-risk.