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.

Prevalence and clinical characterization of oral clefts in patients with chromosome trisomy 18.

OBJECTIVE: To verify the prevalence and perform the clinical characterization of oral clefts in a sample of patients with trisomy of chromosome 18 in Southern Brazil. METHODS: This was a retrospective cross-sectional study, performed in a reference clinical genetic service in Southern Brazil. The initial sample consisted of 77 patients diagnosed in the neonatal period with trisomy 18 treated at the Clinical Genetics Service of a referral hospital at Federal University of Health Sciences of Porto Alegre (UFCSPA). The patients' diagnosis was confirmed by karyotype and care was provided during their stay in the intensive care unit (ICU) of the hospital that is a reference in Southern Brazil for care for malformed patients. The period covered was from 1975 to 2020. RESULTS: During the study period, 77 patients diagnosed with trisomy 18 were treated, most of them in the ICU. Of these, 13 individuals were excluded due to incomplete data. The final sample consisted of 64 patients with an average age of 2.4 years of life, ranging from one day to 16 years old, the majority of whom were female. Regarding face dysmorphisms identified in the sample, three (4,68%) patients had cleft lip and two (3,11%) had cleft lip and palate. CONCLUSIONS: This study contributed to the recognition of the characteristics and prevalence of oral clefts in individuals with trisomy 18 in a sample of patients from Southern Brazil. In addition, we described the clinical alterations found in patients with oral clefts, as well as other associated comorbidities, such as cardiac, neurological and pulmonary comorbidities, as well as cranial and facial dysmorphisms.

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.

Metastatic adrenal gland neuroblastoma in an infant with trisomy 18: A case report.

I present a patient with trisomy 18 associated with neuroblastoma. To the best of my knowledge, this is the second report of such an individual in the relevant literature. A 19-month-old girl known to have trisomy 18 presented with respiratory distress secondary to pleural effusion. Work-up showed metastatic neuroblastoma to multiple sites, and the patient's clinical situation was critical. The physician-parent's decision was not to proceed with treatment of the malignancy. Based on this report, I recommend that physicians remain vigilant and have a high level of suspicion about the potential association between neuroblastoma and trisomy 18. Accordingly, it may be necessary to consider performing serial abdominal ultrasounds and biochemical tests to screen children with trisomy 18 who survive beyond infancy.

The American Association for Thoracic Surgery (AATS) 2023 Expert Consensus Document: Recommendation for the care of children with trisomy 13 or trisomy 18 and a congenital heart defect.

OBJECTIVES: Recommendations for surgical repair of a congenital heart defect in children with trisomy 13 or trisomy 18 remain controversial, are subject to biases, and are largely unsupported with limited empirical data. This has created significant distrust and uncertainty among parents and could potentially lead to suboptimal care for patients. A working group, representing several clinical specialties involved with the care of these children, developed recommendations to assist in the decision-making process for congenital heart defect care in this population. The goal of these recommendations is to provide families and their health care teams with a framework for clinical decision making based on the literature and expert opinions. METHODS: This project was performed under the auspices of the AATS Congenital Heart Surgery Evidence-Based Medicine Taskforce. A Patient/Population, Intervention, Comparison/Control, Outcome process was used to generate preliminary statements and recommendations to address various aspects related to cardiac surgery in children with trisomy 13 or trisomy 18. Delphi methodology was then used iteratively to generate consensus among the group using a structured communication process. RESULTS: Nine recommendations were developed from a set of initial statements that arose from the Patient/Population, Intervention, Comparison/Control, Outcome process methodology following the groups' review of more than 500 articles. These recommendations were adjudicated by this group of experts using a modified Delphi process in a reproducible fashion and make up the current publication. The Class (strength) of recommendations was usually Class IIa (moderate benefit), and the overall level (quality) of evidence was level C-limited data. CONCLUSIONS: This is the first set of recommendations collated by an expert multidisciplinary group to address specific issues around indications for surgical intervention in children with trisomy 13 or trisomy 18 with congenital heart defect. Based on our analysis of recent data, we recommend that decisions should not be based solely on the presence of trisomy but, instead, should be made on a case-by-case basis, considering both the severity of the baby's heart disease as well as the presence of other anomalies. These recommendations offer a framework to assist parents and clinicians in surgical decision making for children who have trisomy 13 or trisomy 18 with congenital heart defect.

[Prenatal diagnosis and outcome of pregnancy for women with high risks by screening of fetal free DNA from peripheral blood samples].

OBJECTIVE: To analyze the results of prenatal diagnosis and outcome of pregnancy for women with a high risk for fetal aneuploidies. METHODS: A total of 747 cases of prenatal diagnosis by amniocentesis due to high risks by non-invasive prenatal testing (NIPT) were selected from January 2015 to March 2022 in the Drum Tower Hospital Affiliated to Nanjing University Medical School. The amniotic fluid samples were subjected to chromosomal karyotyping and/or chromosomal microarray analysis. All cases were followed up by searching the birth information or telephone calls, and the results were recorded. 2 test or F test were used for comparing the difference between the groups. RESULTS: Among the 747 pregnant women with a high risk by NIPT, 387 were true positives, and the overall positive predictive value (PPV) was 51.81%. The PPVs for trisomy 21 (T21), trisomy 18 (T18), trisomy 13 (T13) and sex chromosome aneuploidies (SCA) were 80.24% (199/248), 60% (48/80), 14% (7/50) and 38.97% (106/272), respectively. The PPV for T21 was significantly higher than T18 and T13 (χ2 = 85.216, P < 0.0001). The PPV for other chromosomal aneuploidies and copy number variations (CNVs) were 11.11% (5/45) and 40.74% (22/52), respectively. The PPV for increased X chromosomes was significantly higher than X chromosome decreases (64.29% vs. 22.22%, χ2 = 5.530, P < 0.05). The overall PPV for elder women (≥ 35 years old) was significantly higher than younger women (69.35% vs. 42.39%, χ2 = 49.440, P < 0.0001). For T21 and T18, the PPV of Z ≥ 10 group was significantly higher than that for 3 ≤ Z < 5 group or 5 ≤ Z < 10 group (P < 0.05). Among 52 cases with a high risk for CNVs, the PPV for the ≤ 5 Mb group was significantly higher than the 5 Mb < CNVs < 10 Mb or > 10 Mb groups (60% vs. 30%60% vs. 23.53%, P < 0.05). Among the 387 true positive cases, 322 had opted for induced labor, 53 had delivered with no abnormal growth and development, and 12 were lost during the follow-up. CONCLUSION: The PPVs for common chromosomal aneuploidies are related to the age and Z value of the pregnant women, which were higher in the elder group and higher Z value group. In addition, the PPV is associated with high risk types. The PPV for T21 was higher than T18 and T13, and that for 45,X was lower than 47,XXX, 47,XYY or 47,XXY syndrome. NIPT therefore has relatively high PPVs for the identification of chromosomal CNVs.

[Genetic analysis of the false positive trisomy 7 and false negative trisomy 18 by NIPT-PLUS].

OBJECTIVE: To explore the cause of inconsistency between the results of trisomy 7 by expanded non-invasive prenatal testing (NIPT-PLUS) and trisomy 18 by prenatal diagnosis. METHODS: A pregnant woman who received genetic counseling at Jiaozuo Maternal and Child Health Care Hospital on July 5, 2020 was selected as the study subject. NIPT-PLUS, systematic ultrasound and interventional prenatal testing were carried out. The middle segment and root of umbilical cord, center and edge of the maternal and fatal surface of the placenta were sampled for the validation by copy number variation sequencing (CNV-seq). RESULTS: The result of NIPT-PLUS indicated that the fetus has trisomy 7. Systematic ultrasound has shown multiple malformations including atrioventricular septal defect, horseshoe kidney, and rocker-bottom feet. However, QF-PCR, chromosomal karyotyping analysis, and CNV-seq of amniotic fluid samples all showed that the fetus was trisomy 18. Validation using multiple placental samples confirmed that the middle segment of the umbilical cord contains trisomy 18, the center of the placenta contained trisomy 7, and other placental sites were mosaicism for trisomy 7 and trisomy 18. Notably, the ratio of trisomy 18 became lower further away from the umbilical cord. CONCLUSION: The false positive results of trisomy 7 and false negative trisomy 18 by NIPT-PLUS was probably due to the existence of placental mosaicism. Strict prenatal diagnosis is required needed aneuploidy is detected by NIPT-PLUS to exclude the influence of placental mosaicisms.

Cause, severity, and efficacy of treatment for hearing loss in children with Trisomy 18: A single institution-based retrospective study.

Trisomy 18 is a common chromosomal aberration syndrome, characterized by variable clinical manifestations, including cardiovascular, pulmonary, genitourinary, and musculoskeletal findings, leading to a shorter survival and severe developmental delay in survivors. However, recently, intensive therapeutic intervention has allowed for prolonging survival. In terms of otological complications, only a limited number of relevant reports have been published. To demonstrate the characteristic of hearing loss (HL) in children with Trisomy 18, we retrospectively evaluated 22 patients (44 ears) by comprehensive auditory evaluation with the auditory steady-state response (ASSR) test and temporal bone computed tomography (CT). ASSR revealed that 20 patients (91%) had bilateral moderate to profound HL, more frequent and severe than that in Trisomy 21; among 42 ears having HL, 12 ears (29%) had conductive HL, and 26 ears (62%) had mixed HL. CT scans of 38 ears revealed that 34 ears (89%) had an external and middle ear malformation. Hearing aids (HA) were fitted in 17 patients (air and bone-conduction HAs). The threshold hearing with HA was improved in all of them. Accurate otological evaluation using ASSR and CT and intervention by HAs could be a feasible choice for children with Trisomy 18.

Artificial intelligence for prenatal chromosome analysis.

This review article delves into the rapidly advancing domain of prenatal diagnostics, with a primary focus on the detection and management of chromosomal abnormalities such as trisomy 13 ("Patau syndrome)", "trisomy 18 (Edwards syndrome)", and "trisomy 21 (Down syndrome)". The objective of the study is to examine the utilization and effectiveness of novel computational methodologies, such as "machine learning (ML)", "deep learning (DL)", and data analysis, in enhancing the detection rates and accuracy of these prenatal conditions. The contribution of the article lies in its comprehensive examination of advancements in "Non-Invasive Prenatal Testing (NIPT)", prenatal screening, genomics, and medical imaging. It highlights the potential of these techniques for prenatal diagnosis and the contributions of ML and DL to these advancements. It highlights the application of ensemble models and transfer learning to improving model performance, especially with limited datasets. This also delves into optimal feature selection and fusion of high-dimensional features, underscoring the need for future research in these areas. The review finds that ML and DL have substantially improved the detection and management of prenatal conditions, despite limitations such as small sample sizes and issues related to model generalizability. It recognizes the promising results achieved through the use of ensemble models and transfer learning in prenatal diagnostics. The review also notes the increased importance of feature selection and high-dimensional feature fusion in the development and training of predictive models. The findings underline the crucial role of AI and machine learning techniques in early detection and improved therapeutic strategies in prenatal diagnostics, highlighting a pressing need for further research in this area.

Causes of death in individuals with trisomy 18 after the first year of life.

Mortality in individuals with trisomy 18 has significantly decreased over the past 20 years, but there is scant literature addressing the prognosis and cause of death in individuals with trisomy 18 and survival past the first year of life (YOL). This study analyzed factors associated with mortality and cause of death in a retrospective cohort of 174 individuals with trisomy 18 and survival past the first YOL, the largest such series to date. Data were collected via retrospective survey of parents of affected individuals. Prenatal diagnosis of trisomy 18; postnatal respiratory distress; maternal age > 35 years; birthweight <2000 g; brain and spinal cord defect(s); atrial and/or ventricular septal defect(s); inability to feed orally without medical assistance; and failure to meet sitting and rolling milestones were associated with mortality in this sample. Cause of death was compared between our cohort of individuals with trisomy 18 and existing literature on those with mortality before the first YOL. Individuals with trisomy 18 with mortality after the first YOL demonstrated a predominance of infectious (n = 10/22) and postoperative (n = 6/22) contributing causes of death, in contrast to the existing literature, which shows a predominance of cardiopulmonary causes of death (e.g., cardiopulmonary arrest, pulmonary hypertension). These findings demonstrate that individuals with trisomy 18 and survival past the first YOL have unique medical needs, but further research is needed to develop clinical guidelines for this growing population.

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.

Comprehensive phenotyping of fetuses with trisomy 18: a perinatal center experience.

Trisomy 18 is the second most common aneuploidy after trisomy 21. It presents with varying degrees of heterogeneous clinical phenotypes involving multiple organ systems, with a high mortality rate. Clinical assessment of fetal trisomy 18 is always challenging. In this study, we describe the phenotypes of the fetuses with trisomy 18 from a perinatal cohort. We reviewed fetuses with trisomy 18 in referrals for perinatal autopsy over the period of 15 years. A detailed phenotyping of the fetuses with trisomy 18 was executed by perinatal autopsy. Appropriate fetal tissues were obtained to perform genomic testing. We observed trisomy 18 in 16 fetuses (2%) in our cohort of 784 fetal/neonatal losses and a perinatal autopsy was performed on all of them. Abnormal facial profile was the most frequent anomaly (10/16, 62%) followed by anomalies of the extremities (9/16, 56%), and cardiac defects (6/16, 37%). We also observed esophageal atresia, diaphragmatic hernia, and neural tube defect. The study represents one of the largest cohorts of trisomy 18 from a perinatal center from a developing country and highlights the clinical heterogeneity attributed to trisomy 18. We also report a recurrence of trisomy 18 in a family.

Indications, types, and diagnostic implications of prenatal genetic testing in Sub-Saharan Africa: A descriptive study.

OBJECTIVE: To describe indications, test types, and results of prenatal diagnostic genetic amniocentesis among Ethiopian pregnant women. METHODS: This study was a descriptive study on prenatal diagnostic genetic testing among Ethiopian pregnant women with certain indications and it was conducted at St. Paul's Hospital Millennium Medical College (Addis Ababa, Ethiopia) from January 2017 to April 2023. Data on sociodemographic characteristics, genetic testing indications, types, and results were collected electronically. Data were analysed using SPSS version 23. RESULTS: A total of 159 cases were analysed. The commonest indication for genetic testing among the study subjects was major fetal structural anomalies identified on specialized prenatal anatomic scanning of the index pregnancy detected in 71(44.7%) cases. Down syndrome and Edward syndrome were the commonest genetic aberrations detected accounting for 6.3% (10/159) and 4.4% (7/159), respectively. Among the rare genetic aberration detected were Di-George syndrome (0.6%) and Duchenne muscular dystrophy (0.6%). CONCLUSION: Findings of our study underscore the importance of diagnostic prenatal testing in a Sub-Saharan Africa setting, as common (trisomy 21&18) and rare genetic defects were identified using this important prenatal diagnostic testing. Considering the implications of detecting chromosomal abnormalities for future counselling and care, carrier state in parents for some chromosomal anomalies, and planning post-natal management of some abnormalities that are associated with aneuploidies (notably cardiac anomalies), initiation of diagnostic prenatal genetic testing service at tertiary public health facilities should be acted up on.

Screen-positive rate in cell free DNA screening for trisomy 21.

OBJECTIVE: To assess whether the fetal fraction (FF) has an impact on the screen-positive rate (SPR) in cell-free DNA (cfDNA) screening for trisomy 21. METHODS: Retrospective analysis based on samples analyzed using the Harmony® Prenatal Test (Roche Inc). Due to the size of the data set, we focused on the SPR, which was stratified according to the maternal age, weight, gestational age, and FF distribution. RESULTS: The study cohort consisted of 364,881 patients, including 2614 with a high-risk-result. Median maternal and gestational ages were 34.6 years and 12.4 weeks. FF was dependent on maternal age, weight, and gestational age. SPR was 0.72% and it was independent of maternal weight but was dependent on maternal age. There was a positive but weak association between the FF and the SPR until the FF reached 20.0% (OR p = 1.021, p < 0.001, Nagelkerkes r2 = 0.001). This group included 357,800 pregnancies or 98.1% of the study population. In the group of pregnancies with a FF > 20%, the association was stronger (OR 1.099, p < 0.001, Nagelkerkes r2 = 0.042). CONCLUSION: The SPR in cfDNA screening for trisomy 21 was relatively constant up to a FF of about 20%.