Multiplex Asymmetric PCR by Combining the Amplification Refractory Mutation System with the Homo-Tag-Assisted Nondimer System.

Asymmetric PCR is widely used to produce single-stranded amplicons (ss-amplicons) for various downstream applications. However, conventional asymmetric PCR schemes are susceptible to events that affect primer availability, which can be exacerbated by multiplex amplification. In this study, a new multiplex asymmetric PCR approach that combines the amplification refractory mutation system (ARMS) with the homo-Tag-assisted nondimer system (HANDS) is described. ARMS-HANDS (A-H) PCR utilizes equimolar-tailed forward and reverse primers and an excess Tag primer. The tailed primer pairs initiate exponential symmetric amplification, whereas the Tag primer drives linear asymmetric amplification along fully matched strands but not one-nucleotide mismatched strands, thereby generating excess ss-amplicons. The production of ss-amplicons is validated using agarose gel electrophoresis, sequencing, and melting curve analysis. Primer dimer alleviation is confirmed by both the reduced Loss function value and a 20-fold higher sensitivity in an 11-plex A-H PCR assay than in an 11-plex conventional asymmetric PCR assay. Moreover, A-H PCR demonstrates unbiased amplification by its allele quantitative ability in correct identification of all 31 trisomy 21 samples among 342 clinical samples. A-H PCR is a new generation of multiplex asymmetric amplification approach with various applications, especially when sensitive and quantitative detection is required.

Parents of children with Down syndrome reflect on their postnatal diagnoses, 2003-2022.

A 2003 survey revealed the scope of mothers' dissatisfaction with their postnatal support following a diagnosis of Down syndrome (DS). Substantial proportions of mothers reported that providers conveyed diagnoses with pity, emphasized negative aspects of DS, and neglected to provide adequate materials explaining DS. This study follows up on the 2003 survey by assessing whether parents' experiences have improved. Four DS nonprofit organizations, which participated in the original study, distributed a mixed-methods survey to families who have had children with DS between 2003 and 2022. Quantitative analysis assessed correlations among responses and differences between the 2003 and 2022 survey groups. Open-ended responses were qualitatively analyzed. Compared to the 2003 findings, parents' perceptions of their postnatal care have not improved (N = 89). Parents are increasingly likely to report that their providers pitied them, omitted positive aspects of DS, and provided insufficient materials describing DS. Substantial proportions of parents reported fear (77%) and anxiety (79%), only 24% described receiving adequate explanatory materials, and parents were 45% likelier to report that physicians discussed negative aspects of DS than positive aspects. Qualitatively, substantial numbers of parents recounted insensitive conduct by providers. These results suggest that despite interventions, parents' experiences of postnatal diagnoses of DS have not improved over time. Certain provider behaviors-such as describing positive aspects of DS and providing comprehensive explanatory materials-can reduce fear and anxiety, pointing to directions for reform.

Atypicality index as an add-on to combined first-trimester screening for chromosomal aberrations.

OBJECTIVES: To compute a set of atypicality indices based on combined first-trimester screening (cFTS) markers and second-trimester estimated fetal weight (EFW), and to demonstrate their potential in identifying pregnancies at reduced or increased risk of chromosomal aberrations following a low-risk cFTS result. METHODS: The atypicality index quantifies the unusualness of an individual set of measurements relative to a reference distribution and can be computed from any variables or measurements available. A score of 0% on the atypicality index represents the most typical profiles, while a score of 100% indicates the highest level of atypicality. From the Danish Fetal Medicine Database, we retrieved data on all pregnant women seen for cFTS in the Central Denmark Region between January 2008 and December 2018. All pregnancies with a cytogenetic or molecular analysis obtained prenatally, postnatally or following pregnancy loss or termination were identified. A first-trimester atypicality index (AcFTS) was computed based on nuchal translucency (NT) thickness, maternal serum free ß-human chorionic gonadotropin (ß-hCG) and pregnancy-associated plasma protein-A (PAPP-A). Furthermore, a second-trimester index (AcFTS + EFW) was computed from cFTS markers and EFW from a routine second-trimester anomaly scan. All pregnancies were stratified into subgroups based on their atypicality levels and their cFTS risk estimates. The risk of chromosomal aberrations in each subgroup was then compared with the overall prevalence, and a graphical presentation of the multivariate measurement profiles was developed. RESULTS: We retrieved data on 145 955 singleton pregnancies, of which 9824 (6.7%) were genetically examined. Overall, 1 in 122 (0.82% (95% CI, 0.77-0.87%)) of all pregnancies seen for cFTS were affected by a fetal chromosomal aberration, and in screen-negative pregnancies (cFTS trisomy 21 risk < 1 in 100 and/or trisomy 18/13 risk < 1 in 50), 0.41% (95% CI, 0.38-0.44%) were affected. In screen-negative pregnancies with a typical first-trimester profile (AcFTS < 80%), the risk of chromosomal aberrations was significantly reduced (0.28%) compared with the overall risk. The risk of chromosomal aberrations increased with higher atypicality index to 0.49% (AcFTS [80-90%)), 1.52% (AcFTS [90-99%)) and 4.44% (AcFTS ≥ 99%) and was significantly increased in the two most atypical subgroups. The same applied for the second-trimester atypicality index, with risks of chromosomal aberrations of 0.76% and 4.16% in the two most atypical subgroups (AcFTS + EFW [90-99%) and AcFTS + EFW ≥ 99%, respectively). CONCLUSIONS: As an add-on to cFTS, the atypicality index identifies women with typical measurement profiles, which may provide reassurance, whereas atypical profiles may warrant specialist referral and further investigation. In pregnancies identified as low risk on cFTS but with a highly atypical distribution of NT, PAPP-A and ß-hCG, the risk of a chromosomal aberration is substantially increased. The atypicality index optimizes the interpretation of pre-existing prenatal screening profiles and is not limited to cFTS markers or EFW. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Combined first-trimester screening and invasive diagnostics for atypical chromosomal aberrations: Danish nationwide study of prenatal profiles and detection compared with NIPT.

OBJECTIVES: Our aim was to examine the prenatal profiles of pregnancies affected by an atypical chromosomal aberration, focusing on pathogenic copy-number variants (pCNVs). We also wanted to quantify the performance of combined first-trimester screening (cFTS) and a second-trimester anomaly scan in detecting these aberrations. Finally, we aimed to estimate the consequences of a policy of using non-invasive prenatal testing (NIPT) rather than invasive testing with chromosomal microarray analysis (CMA) to manage pregnancies identified as high risk by cFTS. METHODS: This was a retrospective review of the Danish Fetal Medicine Database of all pregnant women who underwent cFTS and a risk assessment for trisomy 21 between 1 January 2008 and 31 December 2018. Chromosomal aberrations diagnosed prenatally, postnatally or from fetal tissue following pregnancy loss or termination of pregnancy were identified. Chromosomal aberrations were grouped into one of six categories: triploidy; common trisomy (13, 18 or 21); monosomy X; other sex-chromosome aberration (SCA); pCNV; and rare autosomal trisomy (RAT) or mosaicism. The prevalence of each aberration category was stratified by the individual cFTS markers and trisomy 21 risk estimate, and the size of each pCNV diagnosed by CMA was calculated. RESULTS: We retrieved data on 565 708 pregnancies, of which 3982 (0.70%) were diagnosed with a fetal chromosomal aberration. cFTS identified 87% of the common trisomies, but it also performed well in identifying triploidies (86%), monosomy X (92%), atypical SCAs (58%) and RATs or mosaicisms (70%). pCNVs comprised 27% (n = 1091) of the chromosomal aberrations diagnosed overall, and the prevalence increased during the study period, as prenatal CMA was increasingly being performed. In pregnancies with a maternal age < 30 years, nuchal translucency (NT) thickness ≤ 95th centile, pregnancy-associated plasma protein-A (PAPP-A) ≥ 1 multiple of the median, or trisomy 21 risk of ≤ 1 in 1000, the prevalence of pCNVs exceeded significantly the prevalence of trisomies 21, 18 and 13. Pregnancies affected by a pCNV had significantly increased NT and decreased levels of the maternal biomarkers PAPP-A and ß-human chorionic gonadotropin compared with unaffected pregnancies. However, only 23% of these pregnancies screened positive on cFTS and 51% of pCNVs were not detected until after birth. Among high-risk pregnancies, pCNVs comprised 14% of diagnosed aberrations, and when other atypical aberrations were considered, conventional NIPT (screening for trisomies 21, 18 and 13 and monosomy X) would miss 27% of all pathogenic aberrations diagnosed from invasive testing following a high-risk cFTS result. Thus, 1 in 26 pregnancies at high risk following cFTS would be affected by a chromosomal aberration despite a normal result from conventional NIPT. In a contingent screening model using NIPT for the 'intermediate'-risk group (trisomy 21 risk of 1 in 100-299), 50% of the aberrations would be missed. In our cohort, 79% of the pCNVs diagnosed were < 5Mb and therefore not detectable using current forms of 'genome-wide' NIPT. CONCLUSIONS: As a by-product of screening for trisomies 21, 18 and 13, most triploidies and the majority of atypical SCAs, RATs and mosaicisms are detected before birth. However, only 23% of pCNVs are associated with a high-risk result according to cFTS and only half are diagnosed before birth. Replacing invasive testing with NIPT for high-risk pregnancies would substantially decrease the first-trimester detection of pathogenic chromosomal anomalies. © 2024 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Kidney and urological involvement in Down syndrome: frequent, underestimated, but associated with impaired quality of life and risk of kidney failure.

Patients with Down syndrome (DS) are at risk of multiorgan dysfunction; kidney and urological impairment are common. This is due to a likely increased risk of congenital kidney and urological malformations (odds ratio of 4.5 compared to the general population in one study), more frequent associated comorbidities at risk of kidney dysfunction (such as prematurity in 9-24% of children, intrauterine growth retardation or low birth weight in 20%, and congenital heart disease in 44%), and more frequent lower urinary tract dysfunction (reported in 27-77% of children with DS). If present, malformations and comorbidities at risk of kidney dysfunction warrant regular kidney monitoring in addition to their treatment. Serum creatinine in children with DS has been shown to be higher than in the general population and asymptomatic hyperuricemia is reported in 12-33% of children or young adults with DS. Moreover cryptorchidism and testicular cancer are also more common and should be detected by clinical examination. Thus, persons with DS at risk of presenting kidney and urological impairment should be identified by prenatal ultrasonography, comorbidities at risk of kidney sequelae considered, and during regular medical follow-up, clinically examined and questioned to diagnose testicular anomalies and lower urinary tract dysfunction. This is of importance as such kidney and urological impairments are associated with impaired quality of life and mental health, and risk of kidney failure.

Creatinine levels in French children with Down syndrome up to ten years old.

Assess creatinine levels in French children with Down syndrome (DS) on the basis of the relationship between creatinine levels and age. The study included 279 children with DS aged 0 to 10 years who had been regularly monitored between 2004 and 2021 in a single genetics department and who had had at least one creatinine measurement. The creatinine level curves were established by estimating the median and the quantiles of order 2.5 and 97.5% according to age. A Generalized Additive Model for Location, Scale, and Shape was used. The results showed higher creatinine levels in children with DS than in children from the general population.   Conclusion: The present results allow to propose an original chart of creatinine levels according to age in French children with DS, which should help optimize their medical management and improve the early detection of renal diseases. What is Known: • Creatinine is a product of muscle breakdown and depends on muscle mass and children with Down syndrome have muscle and growth characteristics that differ from those of the general paediatric population. • Serum creatinine values in Japanese children with DS are higher than those of children from the general Japanese population. What is New: • Creatinine values in French children with DS are higher than those of children from the general French population. • The proposed original chart for creatinine values according to age, specifically designed for individuals up to 10 years old, should serve for further investigation, prevention, and follow-up of children with DS.

Serum apelin-12 and obesity-related markers in Egyptian children with Down syndrome.

Children with Down syndrome (DS) exhibit higher overweight/obesity rates than their typically developing peers. Apelin-12 is a bioactive adipokine that exerts vital roles in obesity-related cardiometabolic comorbidities. To date, apelin-12 has not been investigated in obese-DS. This study aimed to explore the possible association between serum apelin-12 and obesity-related markers and to evaluate the efficiency of apelin-12 in the prediction of metabolic syndrome (MetS) in obese-DS compared to BMI Z-score matched obese-control. The cross-sectional study included 150 prepubertal children classified into three groups; obese-DS (n = 50), obese-control (n = 50), and normal-weight-control (n = 50). Anthropometric parameters, body adiposity, fasting serum levels of blood glucose (FBG), insulin, lipid profile, and apelin-12 were evaluated. Homeostasis model assessment of insulin resistance (HOMA-IR) was calculated from FBG and insulin. MetS was defined using Adult Treatment Panel III criteria modified for the pediatric age group. ROC curves were analyzed to evaluate the efficiency of apelin-12 in predicting MetS in obesity groups. Obese-DS exhibited higher body adiposity with marked central fat distribution, atherogenic lipid profile, and higher HOMA-IR compared to obese-control. Apelin-12 was significantly higher in obese-DS and obese-DS with MetS compared to obese-control and obese-control with MetS respectively (p < 0.001). The increase in apelin-12 with higher obesity grades was pronounced in obese-DS. Apelin-12 strongly correlated with body adiposity, several MetS risk factors, and HOMA-IR in obese-DS. Significantly higher AUC for apelin-12 in the diagnosis of MetS among obese-DS than obese-control (AUC = 0.948 vs. AUC = 0.807; p = 0.04). CONCLUSIONS:  The current study supports the crucial role of apelin-12 in obesity-related clinical and biochemical markers and in MetS in obese-DS and obese-control. Serum apelin-12 is a potential diagnostic biomarker for MetS with greater performance in obese-DS than obese-control raising its potential for clinical and therapeutic applications. WHAT IS KNOWN: • Obese-DS children displayed excess body adiposity, Pronounced central fat distribution, atherogenic lipid profile, higher HOMA-IR, and higher prevalence of MetS than obese-control. WHAT IS NEW: • Higher serum apelin-12 was observed in obese-DS and obese-DS with MetS than obese-control and obese-control with MetS respectively. The increase in apelin-12 level with increasing obesity grades was more pronounced in obese-DS. • Apelin-12 strongly correlated with obesity-related markers and MetS components in obese-DS. Apelin-12 performed better as a diagnostic biomarker for MetS in obese-DS than obese-control.

Pregnant women's informational needs prior to decisions about prenatal diagnosis for chromosomal anomalies-A Q methodological study.

OBJECTIVE: To study pregnant women's subjective viewpoints on what is important when receiving information prior to decision-making regarding prenatal testing for chromosomal anomalies. METHOD: Data were collected using Q methodology. During January 2020-October 2021, 45 pregnant women in Sweden completed a 50-item Q sort. Statements regarding what is important when receiving information about prenatal screening and diagnosis were prioritized through ranking in a fixed sorting grid on an 11-point scale, from "most important" to "least important." Socio-demographics and coping styles were surveyed through questionnaires. RESULTS: Three groups represented different viewpoints on what pregnant women consider important when receiving information about prenatal screening and diagnosis. Factor 1: Stepwise information and decision-making: viewing information and decision-making as a step-by-step process. Factor 2: Decision-making as a continuous process based on couple autonomy: Striving for an informed decision as a couple about tests, test results and conditions screened. Factor 3: As much information as early as possible-the importance of personal autonomy in decision-making: Prioritizing autonomous decision-making based on non-directive information early in the pregnancy. CONCLUSION: This study highlights the complexities involved when providing information. As shown by the differing viewpoints in this study, pregnant women's informational needs differ, making individual and personalized information preferable.

Current controversies in prenatal diagnosis: Noninvasive prenatal testing should replace other screening strategies for fetal trisomies 13, 18, 21.

This is a written summary of the oral debate presented at the International Society for Prenatal Diagnosis annual conference in Edinburgh in 2023. The topic under debate is whether noninvasive prenatal testing (NIPT) using cell-free fetal DNA should replace other screening strategies for the detection of fetal trisomies 13, 18, 21. There is no disagreement that NIPT is far more sensitive and has better positive predictive values for identifying trisomies 13, 18, and 21 than traditional screening approaches using biochemical markers and measurement of nuchal translucency. The major issue lies in the potential adverse consequences associated with abandoning traditional screening methods. The source of disagreement stems primarily from whether you consider the role of ultrasound in the context of screening to be strictly for nuchal translucency measurement or whether it should be combined with a fetal anatomy scan. The debate featured two experts who presented evidence in favor of each argument.

Very elevated hCGß (≥10 multiple of the median) in maternal marker screening for Down syndrome: Frequency, etiologies, outcomes, and guidelines.

AIM: This aim of this study was to detail maternal and fetal anomalies observed on a national scale in a large French cohort of patients presenting high hCG values (≥10 multiple of the median [MoM]) at Down syndrome screening in order to define clear and optimal guidelines. METHODS: This is a retrospective multicenter study based on a French annual database of all trisomy 21 screenings. Our study targeted and studied cases with hCG or hCGß values ≥10 MoM. Complementary exams and outcomes were analyzed. RESULTS: The calculated frequency was 0.05% for hCGß ≥10 MoM in unselected patients. For this series of 289 cases, a complication of the pregnancy or a poor outcome was observed in 145 cases (51%) as follows: 96 (66%) cases of fetal disease, 23 (16%) of maternal disease, 5 (3.5%) of placental anomalies and 21 (14.5%) of systemic disease concerning mother, fetus and placenta. CONCLUSION: This study establishes the frequency of hCG or hCGß values ≥10 MoM, presents a flow chart that optimizes follow-up, and gives clear information for patients presenting with such abnormal values at trisomy 21 screening.

Performance of cell-free DNA testing for common fetal trisomies in triplet pregnancies.

OBJECTIVE: In singleton pregnancies, the use of cell-free DNA (cfDNA) analysis as a screening test for common fetal trisomies has spread worldwide though we still lack sufficient data for its use in triplet pregnancies. The objective of this study is to assess the performance of cfDNA testing in detecting fetal aneuploidies in triplet pregnancies as a first-tier test. METHOD: We performed a retrospective cohort study including data from pregnant women with a triplet pregnancy who underwent cfDNA testing between May 1, 2017, and January 15, 2020. cfDNA was obtained by massive parallel sequencing (VeriSeq NIPT solution; Illumina®). The objectives of the study were to assess the diagnostic performance of cfDNA testing for trisomy 21 (T21) (primary outcome), trisomy 18 (T18) and 13 (secondary outcomes). RESULTS: During the study period, cfDNA testing was performed in 255 women with triplet pregnancy, of which 165 (64.7%) had a neonatal outcome available. Three tests were positive for T21, one of which was confirmed by an antenatal karyotype, and the other was confirmed at birth. The third case did not undergo an invasive procedure and was not confirmed at birth (false positive). In one case, cfDNA testing was positive for T18 and was confirmed by an antenatal karyotype. There were no cases of trisomy 13 in the cohort. The no-call rate was 2.4% at first sampling. Fifty-eight (22.7%) women had embryo reduction, which in 40 (69%) of whom was performed after the cfDNA test result. CONCLUSION: cfDNA testing could be offered as primary screening for main fetal aneuploidies in triplet pregnancies after provision of appropriate patient information.

Analysis of Prenatal Serological Screening of 116 Pregnant Women with Trisomy 21 Syndrome Fetus.

BACKGROUND: Prenatal serological screening is commonly used to screen for trisomy 21 syndrome (T21); however, it carries a risk of missed detection. In this study, we explored how to reduce missed diagnosis of T21 in serological screening. METHODS: A total of 116 pregnant women with T21 fetuses confirmed by prenatal diagnosis were evaluated. Serological screening and non-invasive prenatal test (NIPT) findings were analyzed. RESULTS: Twenty-nine T21 fetuses were missed in serological screening; the missed diagnosis rate was 25%, 67.65% of the missed cases were of moderate risk, and 79.31% of the missed pregnant women were under 35 years of age. Nuchal translucency (NT) and the free beta subunit of human chorionic gonadotropin (free-HCGß) were higher in the detected T21 cases than in the missed T21 cases, while alpha-fetoprotein (AFP) levels were decreased. Forty-eight pregnant women who underwent NIPT in the second trimester were at high-risk for T21. CONCLUSIONS: Prenatal screening should not be ignored in young pregnant women. For serological screening, moderate risk and abnormal single serum markers should also receive greater attention. NIPT can be extended to first-tier screening.

SARS-CoV-2 Infection Increases High Risk Rate of Down Syndrome Screening Test by Reducing Alpha-Fetoprotein.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has been a significant global health issue in recent years. Numerous studies indicate that COVID-19 during pregnancy is associated with an increased likelihood of pregnancy complications. Additionally, pregnancy itself is known to elevate the risk of severe SARS-CoV-2 infection. To explore the potential impact of SARS-CoV-2 infection on the probability of Down syndrome in fetuses, we conducted serological testing of Down syndrome markers in pregnant women who had contracted the virus. METHODS: Serological experiments were conducted utilizing a particle chemiluminescence test. The cohort of pregnant women was categorized into three groups: a control group with no infection, a group infected with SARS-CoV-2 Omicron within the first six weeks of gestation, and a group infected beyond the sixth week of gestation. RESULTS: In the group of individuals infected within 6 gestational weeks, the infection resulted in a decrease in alpha-fetoprotein (AFP) levels and a higher positive rate of Down syndrome screening tests (p ˂ 0.05). However, in this study, SARS-CoV-2 infection did not lead to an increase in the occurrence of Down syndrome in the fetus. The positive rate of women infected beyond 6 gestational weeks was slightly higher than the non-infected group (6.2% vs. 5.7%), but these differences were not statistically significant (p > 0.05). Within the group infected beyond 6 gestational weeks, there was, compared to the control group, a decrease in free beta human chorionic gonadotropin (ß-hCG) levels (p < 0.05). CONCLUSIONS: This study presents a novel investigation into the impact of SARS-CoV-2 infection on AFP and ß-hCG levels. It has been observed that pregnant women who contract SARS-CoV-2 may exhibit an increased likelihood of positive results in serum tests conducted for Down syndrome screening. However, it is important to note that the occurrence of Down syndrome in the developing fetus does not appear to be elevated. To validate these findings, additional research involving larger and diverse cohorts is necessary.

Correlation between telomere shortening in maternal peripheral blood and fetal aneuploidy.

BACKGROUND: This study aimed to assess whether maternal telomere length is a more accurate predictor of trisomy 21 than maternal age while also exploring the factors influencing maternal and fetal telomere length. METHODS: Forty mothers with fetuses carrying extra maternal copies of chromosome 21 were defined as trisomy 21 cases, and 18 mothers with normal karyotype fetuses were defined as controls. Telomere lengths of maternal blood lymphocytes and amniotic fluid cells were determined using real-time polymerase chain reaction. Fetal and maternal telomere lengths were compared between the two groups. Moreover, we analyzed the factors influencing maternal and fetal telomere length in the trisomy 21 pedigree. A logistic regression model was used to analyze the correlation between maternal telomere length and trisomy 21 risk. In addition, receiver operating characteristic (ROC) curve analysis was used to determine the accuracy of using maternal telomere length as an indicator of trisomy 21 risk. RESULTS: The study revealed that both maternal and fetal telomere lengths were significantly shorter in trisomy 21 cases than in the controls. In the trisomy 21 group, the maternal age, occupation, and nationality showed no significant correlation with their telomere length; fetal telomere length exhibited a positive correlation with maternal telomere length. Furthermore, maternal telomere length shortening is associated with trisomy 21 (OR = 0.311; 95% CI, 0.109-0.885, P < 0.05). The results of ROC curve analysis indicated that a combined assessment of maternal age and maternal telomere length predicted fetal chromosome trisomy more effectively than a single assessment (area under the curve 0.808, 95% CI, 0.674-0.941, P < 0.001). CONCLUSION: Maternal age combined with maternal telomere length proved to be a superior predictor of trisomy risk. Additionally, maternal telomere length was found to influence fetal telomere length.

Potential efficacy of digital polymerase chain reaction for non-invasive prenatal screening of autosomal aneuploidies: a systematic review and meta-analysis.

BACKGROUND: Digital Polymerase Chain Reaction (dPCR) presents a promising approach for quantifying DNA and analyzing copy number variants, particularly in non-invasive prenatal testing. This method offers a streamlined and time-efficient procedure in contrast to the widely used next-generation sequencing for non-invasive prenatal testing. Studies have reported encouraging results for dPCR in detecting fetal autosomal aneuploidies. Consequently, this systematic review aimed to evaluate the effectiveness of dPCR in screening for trisomy 21, 18, and 13. METHODS: A systematic search was conducted in PubMed, Web of Sciences, and Embase for relevant articles published up to December 30, 2023. The Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) was utilized for the quality assessment of the included articles. Furthermore, a bivariate random-effect regression model was used to conduct a meta-analysis on the utility of dPCR for trisomy 21 screening. RESULTS: A total of 9 articles were included in this review, with all of them assessing the utility of dPCR in trisomy 21 screening, and 2 and 1 studies conducting additional analysis on the screening abilities of dPCR for trisomy 18 and 13, respectively. A bivariate random-effects model calculated pooled sensitivity and specificity with a 95% confidence interval (CI). Meta-analysis of 6 studies comparing trisomy-21 screening with karyotyping demonstrated dPCR's pooled sensitivity of 98% [95% CI: 94 -100] and specificity of 99% [95% CI: 99 -100]. While conducting a meta-analysis for trisomy 13 and 18 proved impractical, reported values for sensitivity and specificity were favorable. CONCLUSIONS: These findings suggest that dPCR holds promise as an effective tool for non-invasive prenatal testing, presenting a less time-consuming and intricate alternative to next-generation sequencing. However, further research is necessary to evaluate dPCR's applicability in clinical settings and to delineate its specific advantages over next-generation sequencing. This study contributes valuable insights into the potential of dPCR for enhancing prenatal screening methodologies. TRIAL REGISTRATION: The protocol of this study was registered in the International Prospective Register of Systematic Reviews (PROSPERO) on 7/3/2024, with a registration code of CRD42024517523.

Pregnancies with 'double-positive' multiple marker screening results: a population-based study in Ontario, Canada.

BACKGROUND: Multiple marker screening is offered to pregnant individuals in many jurisdictions to screen for trisomies 21 and 18. On occasion, the result is 'double-positive'-a screening result that is unexpectedly positive for both aneuploidies. Although this occurs rarely, the paucity of available evidence about the outcomes of these pregnancies hinders patient counselling. This study aimed to investigate the association of double-positive results with preterm birth and other adverse perinatal outcomes. METHODS: We conducted a population-based retrospective cohort study of pregnancies with an estimated date of delivery from September 1, 2016, to March 31, 2021, using province-wide perinatal registry data in Ontario, Canada. Pregnancies with double-positive screening results where trisomies 21 and 18 were ruled-out were compared to pregnancies with screen negative results for both aneuploidies. We used modified Poisson regression models with robust variance estimation to examine the association of double positive results with preterm birth and secondary outcomes. RESULTS: From 429 540 pregnancies with multiple marker screening, 863 (0.2%) had a double-positive result; trisomies 21 and 18 were ruled out in 374 pregnancies, 203 of which resulted in a live birth. Among the pregnancies in the double-positive group resulting in a live birth, the risk of preterm birth was increased compared to pregnancies with a screen negative result: adjusted risk ratio (aRR) 2.6 (95%CI 2.0-3.6), adjusted risk difference (aRD) 10.5% (95%CI 5.4-15.7). In a sensitivity analysis excluding all diagnosed chromosomal abnormalities, the risk of preterm birth remained elevated to a similar degree: aRR 2.6 (95%CI 1.9-3.7), aRD 10.0% (95%CI 4.8-15.3). The risk of other adverse perinatal outcomes was also higher, including the risk of chromosomal abnormalities other than trisomies 21 and 18: aRR 81.1 (95%CI 69.4-94.8), aRD 34.0% (95%CI 29.2-38.8). Pregnancies with double-positive results were also less likely to result in a live birth, even when excluding all diagnosed chromosomal abnormalities; and at increased risk of adverse perinatal outcomes for those resulting in a live birth. CONCLUSION: Although rare, double-positive multiple marker screening results are associated with an increased risk of preterm birth and other adverse perinatal outcomes, even when excluding all identified chromosomal abnormalities.

Maternal age and the risk of fetal aneuploidy: A nationwide cohort study of more than 500 000 singleton pregnancies in Denmark from 2008 to 2017.

INTRODUCTION: In this register-based study of pregnancies in Denmark, we assessed the associations between maternal age and the risk of fetal aneuploidies (trisomy 21, trisomy 18, trisomy 13, triploidy, monosomy X and other sex chromosome aberrations). Additionally, we aimed to disentangle the maternal age-related effect on fetal aneuploidies by cases with translocation trisomies and mosaicisms. MATERIAL AND METHODS: We followed a nationwide cohort of 542 375 singleton-pregnant women attending first trimester screening in Denmark between 2008 and 2017 until delivery, miscarriage or termination of pregnancy. We used six maternal age categories and retrieved information on genetically confirmed aneuploidies of the fetus and infant from the national cytogenetic register. RESULTS: We confirmed the known associations between advanced maternal age and higher risk of trisomy 21, 18, 13 and other sex chromosome aberrations, especially in women aged ≥35 years, whereas we found no age-related associations with triploidy or monosomy X. Cases with translocation trisomies and mosaicisms did not influence the overall reported association between maternal age and aneuploidies. CONCLUSION: This study provides insight into the accurate risk of fetal aneuploidies that pregnant women of advanced ages encounter.

Awareness of down syndrome screening among educated Muslim women is associated with a favorable attitude toward testing.

OBJECTIVE: There is a general assumption that Muslim women refuse Down syndrome screening, and therefore, many health practitioners do not offer it or briefly discuss it with their participants. This study aims to objectively assess women's awareness, knowledge, and attitudes toward Down Syndrome screening (D.S.S) in a Muslim-majority population. METHODS: We conducted a cross-sectional study among attendees of antenatal clinics at a major university hospital in Saudi Arabia, aiming for a sample size of at least 385 Muslim women. A semi-structured questionnaire assessed awareness of different D.S.S. options and the source of that information (2 items), specific knowledge of D.S.S. (14 items), and attitudes (4 items). The knowledge and attitudes scores were calculated using a five-level agreement Likert-type scale. RESULTS: Among 434 participants, with an even distribution among all age groups and a majority of a college degree holder or higher (71%), 178 (41.0%) reported awareness of D.S.S. Factors associated with increased awareness were maternal age above 40 or those under 30, nulliparity, and extended family history of fetal congenital anomalies (P-value = 0.03,0.015, and 0.017, respectively). Recognized tests were ultrasound measurement of nuchal translucency (71.9%) and first-trimester serum screening (58.4%). The sources of knowledge were obstetricians (53.9%), followed by family and friends (27.0%). The overall mean ± SD knowledge score was 53.9 ± 8.7 out of 70, and the mean attitude score was 17.4 ± 2.9 out of 20. Having 1 or 2 children is associated with a higher knowledge score, and most participants who reported awareness of D.S.S. (51.7%) had a favorable attitude toward screening. CONCLUSION: Awareness of D.S.S. among Muslim women is associated with favorable attitudes towards testing, contradicting the general assumption and highlighting the need for systematic education to increase awareness and subsequent testing uptake.

Prevalence, associated risk factors, and respiratory event distribution of obstructive sleep apnea in children with Down syndrome.

PURPOSE: Children with Down Syndrome (DS) have a high prevalence of obstructive sleep apnea (OSA). We aimed to assess OSA prevalence in a single center cohort of children with DS, identify associated risk factors of obstructive respiratory events, and examine the influence of different sleep stages and body positions on respiratory events distribution. METHODS: Single center retrospective study that included children with DS who underwent overnight polysomnogram (PSG). OSA severity was categorized by obstructive apnea-hypopnea index (OAHI) as mild (1.5-4.9 events/h), moderate (5-9.9 events/h), and severe (≥ 10 events/h). A logistic regression analysis was used to examine the association between OSA-related risk factors in normal and abnormal OAHI category and in REM and Non-REM predominant AHI groups. RESULTS: PSG data were available for 192 children with a median age of 5 years (IQR 7). OSA prevalence was 82.3% (27.1% mild, 19.8% moderate, and 35.4% severe). A logistic regression model identified BMI and being an African American as significant predictors for OAHI severity. In children with OSA, the median OAHI was 7.6 and obstructive respiratory events were more common in REM sleep and in the supine position. The median REM OAHI was 20 events/h (IQR: 24.4), whereas the median Non-REM OAHI was 5.2 events/h (IQR: 12.6 p < 0.0001). Similarly, supine OAHI was 11.6 (IQR: 19.3) and off supine OAHI was 6.6 (IQR: 11.6, p = 0.0004). Age was a significant predictor (p = 0.012) for Non-REM predominant OSA which was present in 15.2% of children with OSA. CONCLUSION: Children with DS have a high prevalence of OSA. Higher BMI and being an African American were significant associated risk factors for higher OAHI. Obstructive respiratory events in children with DS occur predominantly in REM sleep and in the supine position. Non-REM predominant distribution of respiratory events was noted in older children with DS.

Application of Patient-Based Real-Time Quality Control Based on Artificial Intelligence Monitoring Platform in Continuously Quality Risk Monitoring of Down Syndrome Serum Screening.

BACKGROUND: Patient-based real-time quality control (PBRTQC) has gained attention because of its potential to continuously monitor the analytical quality in situations wherein internal quality control (IQC) is less effective. Therefore, we tried to investigate the application of PBRTQC method based on an artificial intelligence monitoring (AI-MA) platform in quality risk monitoring of Down syndrome (DS) serum screening. METHODS: The DS serum screening item determination data and relative IQC data from January 4 to September 7 in 2021 were collected. Then, PBRTQC exponentially weighted moving average (EWMA) and moving average (MA) procedures were built and optimized in the AI-MA platform. The efficiency of the EWMA and MA procedures with intelligent and traditional control rules were compared. Next, the optimal EWMA procedures that contributed to the quality assurance of serum screening were run and generated early warning cases were investigated. RESULTS: Optimal EWMA and MA procedures on the AI-MA platform were built. Comparison results showed the EWMA procedure with intelligent QC rules but not traditional quality rules contained the best efficiency. Based on the AI-MA platform, two early warning cases were generated by using the optimal EWMA procedure, which finally found were caused by instrument failure. Moreover, the EWMA procedure could truly reflect the detection accuracy and quality in situations wherein traditional IQC products were unstable or concentrations were inappropriate. CONCLUSIONS: The EWMA procedure built by the AI-MA platform could be a good complementary control tool for the DS serum screening by truly and timely reflecting the detection quality risks.