Prenatal Chromosomal Microarray Analysis Research Articles

Postnatal Outcomes of Fetal Variants of Unknown Significance in Prenatal Chromosomal Microarray Analysis: A Single-Center Study.

Chromosomal microarray analysis (CMA) can identify clinically significant microdeletions and microduplications, providing valuable insights into the genetic basis of various disorders. Our study was to evaluate clinical management and prognosis of fetuses with prenatal variants of unknown significance (VOUS) and determine diagnostic approaches for subsequent pregnancies. This study included 2,953 fetuses undergoing CMA at the Prenatal Diagnostic Center of Changzhou Maternal and Child Health Care Hospital from January 2018 to December 2022, identifying 162 cases with VOUS. Parent-of-origin testing determined the origin of copy number variations. Prenatal genetic counseling was provided, and outcomes were followed for 3-36 months post-birth. All 162 VOUS cases received prenatal genetic counseling. Among these, 123 continued the pregnancy; 22 chose termination, and 17 were lost to follow-up. Of the continuations, 116 delivered at term and 7 preterm. Post-birth follow-up showed 5/123 live-born fetuses developed relevant clinical phenotypes. Parent-of-origin testing in 21 cases identified 18 hereditary and 3 de novo variants. Additionally, five subsequent pregnancies were monitored, with two undergoing amniocentesis and three receiving low-risk noninvasive prenatal testing, all with positive outcomes. VOUS, occurring in approximately 5% of cases, require comprehensive prenatal genetic counseling and show generally favorable outcomes. Despite low association with adverse clinical phenotypes, the importance of postnatal follow-up and regular report updates is emphasized to detect potential clinical associations early.

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

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. 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. 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 β-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. 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.

Prenatal chromosomal microarray analysis in a large Chinese cohort of fetuses with congenital heart defects: a single center study

Background and objectivesCongenital heart defect (CHD) is one of the most common birth defects. The aim of this cohort study was to evaluate the prevalence of chromosomal abnormalities and the clinical utility of chromosomal microarray analysis (CMA) in fetuses with different types of CHD, aiming to assist genetic counseling and clinical decision-making.MethodsIn this study, 642 fetuses with CHD were enrolled from a single center over a six-year period (2017–2022). Both conventional karyotyping and CMA were performed simultaneously on these fetuses.ResultsThe diagnostic yield of CMA in fetuses with CHD in our study was 15.3% (98/642). Our findings revealed a significant increase in the diagnostic yield of CMA compared to karyotyping in fetuses with CHD. Among CHD subgroups, the diagnostic yields were high in complex CHD (34.9%), conotruncal defects (28.6%), right ventricular outflow tract obstructive defects (RVOTO) (25.9%), atrioventricular septal defects (AVSD) (25.0%) and left ventricular outflow tract obstructive defects (LVOTO) (24.1%), while those in other CHD (10.6%) and septal defects (10.9%) were relatively low. The overall detection rate of clinically significant chromosomal abnormalities was significantly higher in the non-isolated CHD group compared to the isolated CHD group (33.1% vs. 9.9%, P < 0.0001). Interestingly, numerical chromosomal abnormalities were more likely to occur in the non-isolated CHD group than in the isolated CHD group (20.3% vs. 2.0%, P < 0.0001). The rate of termination of pregnancy (TOP)/Still birth in the non-isolated CHD group was significantly higher than that in the isolated CHD group (40.5% vs. 20.6%, P < 0.0001). Compared to the isolated CHD group, the detection rate of clinically significant chromosomal abnormalities was significantly higher in the group of CHD with soft markers (35.6% vs. 9.9%, P < 0.0001) and in the group of CHD with additional structural anomalies (36.1% vs. 9.9%, P < 0.0001).ConclusionsCMA is a reliable and high-resolution technique that should be recommended as the front-line test for prenatal diagnosis of fetuses with CHD. The prevalence of chromosomal abnormalities varies greatly among different subgroups of CHD, and special attention should be given to prenatal non-isolated cases of CHD, especially those accompanied by additional structural anomalies or soft markers.

Fetal agenesis of corpus callosum: chromosomal copy number abnormalities and postnatal follow-up

ObjectiveAgenesis of the corpus callosum (ACC) is an anomaly that can occur in fetuses during pregnancy. However, there is currently no treatment for fetal ACC. Therefore, we conducted a retrospective analysis of obstetric outcomes of fetal ACC to explore the relationship between fetal ACC phenotypes and chromosomal copy number abnormalities.Methods and resultsAmniotic fluid or umbilical cord blood were extracted from pregnant women with fetal ACC for karyotype analysis and chromosomal microarray analysis (CMA). Among the 48 fetuses with ACC, 22 (45.8%, 22/48) had isolated ACC, and 26 (54.2%, 26/48) had non-isolated ACC. Chromosomal abnormalities were detected via karyotype analysis in four cases. In addition to the four cases of pathogenic copy number variations (CNVs) detected using karyotype analysis, CMA revealed two cases of pathogenic CNVs with 17q12 microduplication and 16p12.2 microdeletion. The obstetric outcomes of 26 patients with non-isolated ACC were followed up, and 17 chose to terminate the pregnancy. In addition, seven of the nine cases with non-isolated ACC showed no obvious abnormality during postnatal follow-up, whereas only one case with normal CMA showed an abnormal phenotype at six months. Of the 22 patients with isolated ACC, six chose to terminate the pregnancy. Postnatal follow-up of 16 isolated ACC cases revealed only one with benign CNV, presenting with intellectual disability.ConclusionPregnant women with fetal ACC should be offered prenatal CMA, particularly non-isolated ACC. Patients with ACC should undergo prolonged postnatal follow-up, and appropriate intervention should be provided if necessary.

Selection of prenatal screening with nuchal translucency > 95th centile and below 99th centile: a 4-year observational study with real-world data.

We sought to analyze the genetic outcomes of fetuses with nuchal translucency (NT) > 95th centile, and determine whether prenatal genetic counseling, chromosomal microarray analysis (CMA) or non-invasive prenatal testing (NIPT) are truly beneficial for the outcomes of fetuses with increased NT > 95th centile and below 99th centile. A total of 535 pregnant women were included in this study, with a fetal NT > 95th centile at 11-13+6weeks of gestation from January 2017 to December 2020. 324 pregnant women with fetal NT > 95th centile and below 99th centile combined with other risk factors and NT > 99th centile received prenatal diagnostic karyotype analysis and CMA, and 211 pregnant women with fetal isolated increased NT > 95th centile and below 99th centile were selected to carry out NIPT. A total of 211 pregnant women who underwent NIPT were included in the study, NIPT results showed that 8 high-risk cases were confirmed by prenatal diagnosis. Overall, the detection rate of NIPT was 3.79%. A total of 324 pregnant women with fetal NT > 95th centile and below 99th centile, along with other risk factors, and those with fetal NT > 99th centile, received karyotype analysis and CMA for prenatal diagnosis. Among them, a total of 73 genetic abnormalities were detected, including 45 cases of chromosomal aneuploidy, 7 cases of structural abnormalities, and 21 cases of copy number variations (CNVs) with a size of less than 10Mb. In addition, the 73 women with genetic abnormalities are divided into three groups based on the NT measurement (Group 1: Fetuses with NT > 95th centile and below 99th centile, Group 2: Fetuses with NT > 99th centile, and Group 3: Fetuses with NT > 99th centile). 13.11% (8/61) of pathogenic genetic abnormalities (6 chromosomal aneuploidy, 1 structural abnormality, and 1 likely pathogenic CNV) will be missed if genetic counseling and prenatal genetic testing were not conducted in fetuses with increased NT > 95th centile and below 99th centile combined with other risks. Pathogenic CNVs were the most common abnormalities in group 3, and one likely pathogenic CNV was detected in group 1 and group 3, respectively, and a total of 14 CNVs of unknown clinical significance (VOUS) were detected. Through this study, we demonstrated that the critical value of NT > 95th centile for invasive detection or NIPT. Invasive testing combined with CMA may be recommended for fetuses with NT > 95th centile and below 99th centile and with other risks. But when isolated NT > 95th centile and below 99th centile, NIPT would be appropriate.

Prenatal chromosomal microarray analysis and karyotyping in fetuses with isolated choroid plexus cyst: A retrospective case-control study

ObjectivesTo evaluate the the diagnostic yield of chromosomal microarray analysis (CMA) in fetuses with isolated CPC (iCPC). MethodsA total of 315 fetuses with iCPC (iCPC group) and 364 fetuses without abnormal ultrasound findings (control group) were recruited between July 2014 to March 2018. ResultsThe overall diagnostic yield of chromosomal abnormalities by CMA and karyotyping in iCPC group was up to 4.1 %, higher than 1.4 % in the control group, p < 0.05. The detection rate of pathogenic or likely pathogenic copy number variants (CNVs) with clinical significance by CMA in iCPC group (1.3 %) was higher than in control group (0 %), p < 0.05. According to the type of chromosome abnormalities, the missed diagnosis rate of non-invasive prenatal testing (NIPT) was 1.6 % in our study. ConclusionsThe presence of iCPC on ultrasound examination suggests a potential indication for genetic counseling. Karyotyping and chromosomal microarray analysis may be considered for fetuses with iCPC. It is important to be aware of the limitations of non-invasive prenatal testing, as there is a possibility of residual risk.

Incremental yield of whole-genome sequencing over chromosomal microarray analysis and exome sequencing for congenital anomalies in prenatal period and infancy: systematic review and meta-analysis.

First, to determine the incremental yield of whole-genome sequencing (WGS) over quantitative fluorescence polymerase chain reaction (QF-PCR)/chromosomal microarray analysis (CMA) with and without exome sequencing (ES) in fetuses, neonates and infants with a congenital anomaly that was or could have been detected on prenatal ultrasound. Second, to evaluate the turnaround time (TAT) and quantity of DNA required for testing using these pathways. This review was registered prospectively in December 2022. Ovid MEDLINE, EMBASE, MEDLINE (Web of Science), The Cochrane Library and ClinicalTrials.gov databases were searched electronically (January 2010 to December 2022). Inclusion criteria were cohort studies including three or more fetuses, neonates or infants with (i) one or more congenital anomalies; (ii) an anomaly which was or would have been detectable on prenatal ultrasound; and (iii) negative QF-PCR and CMA. In instances in which the CMA result was unavailable, all cases of causative pathogenic copy number variants > 50 kb were excluded, as these would have been detectable on standard prenatal CMA. Pooled incremental yield was determined using a random-effects model and heterogeneity was assessed using Higgins' I2 test. Subanalyses were performed based on pre- or postnatal cohorts, cases with multisystem anomalies and those meeting the NHS England prenatal ES inclusion criteria. A total of 18 studies incorporating 902 eligible cases were included, of which eight (44.4%) studies focused on prenatal cohorts, incorporating 755 cases, and the remaining studies focused on fetuses undergoing postmortem testing or neonates/infants with congenital structural anomalies, constituting the postnatal cohort. The incremental yield of WGS over QF-PCR/CMA was 26% (95% CI, 18-36%) (I2 = 86%), 16% (95% CI, 9-24%) (I2 = 85%) and 39% (95% CI, 27-51%) (I2 = 53%) for all, prenatal and postnatal cases, respectively. The incremental yield increased in cases in which sequencing was performed in line with the NHS England prenatal ES criteria (32% (95% CI, 22-42%); I2 = 70%) and in those with multisystem anomalies (30% (95% CI, 19-43%); I2 = 65%). The incremental yield of WGS for variants of uncertain significance (VUS) was 18% (95% CI, 7-33%) (I2 = 74%). The incremental yield of WGS over QF-PCR/CMA and ES was 1% (95% CI, 0-4%) (I2 = 47%). The pooled median TAT of WGS was 18 (range, 1-912) days, and the quantity of DNA required was 100 ± 0 ng for WGS and 350 ± 50 ng for QF-PCR/CMA and ES (P = 0.03). While WGS in cases with congenital anomaly holds great promise, its incremental yield over ES is yet to be demonstrated. However, the laboratory pathway for WGS requires less DNA with a potentially faster TAT compared with sequential QF-PCR/CMA and ES. There was a relatively high rate of VUS using WGS. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Prenatal genetic diagnosis associated with fetal ventricular septal defect: an assessment based on chromosomal microarray analysis and exome sequencing

Objective: In the study, we investigated the genetic etiology of the ventricular septal defect (VSD) and comprehensively evaluated the diagnosis rate of prenatal chromosomal microarray analysis (CMA) and exome sequencing (ES) for VSD to provide evidence for genetic counseling.Methods: We carried out chromosomal microarray analysis (CMA) on 468 fetuses with VSD and exome sequencing (ES) on 51 fetuses.Results: In our cohort, 68 (14.5%) VSD fetuses received a genetic diagnosis, including 61 (13.03%, 61/468) cases with chromosomal abnormalities and seven (13.7%, 7/51) cases with gene sequence variants. The detection rate of total pathogenic and likely pathogenic gene variations in the non-isolated VSD group (61/335, 18.2%, 55 by QF-PCR/karyotype/CMA + 6 by ES) was significantly higher than that in the isolated VSD group (7/133, 5.3%, 6 by QF-PCR/karyotype/CMA + 1 by ES, p = 0.000). The most common copy number variation (CNV) was 22q11.2 microdeletion syndrome. Additionally, we found six previously unreported variants, which expanded the variation spectrum of VSD-related genes.Conclusion: In this study, CNVs and sequence variants were found in 13.03% and 13.7% of cases, respectively. ES can be recommended for fetuses with VSD without chromosome abnormalities and pathogenic CNVs, especially those that are combined with other ultrasound abnormalities.

Genetic analysis, ultrasound phenotype, and pregnancy outcomes of fetuses with Xp22.33 or Yp11.32 microdeletions.

The phenotypes of Xp22.33 or Yp11.32 microdeletions comprising the short-stature homeobox (SHOX) gene have been extensively described in adults and children. Herein, the prenatal ultrasound phenotype and pregnancy outcomes of fetuses with Xp22.33/Yp11.32 microdeletions were analyzed to improve our understanding, diagnosis, and monitoring of this genetic condition in the fetal stage. A total of 9,100 pregnant women referred to tertiary units for prenatal diagnosis were evaluated by chromosomal microarray analysis(CMA). Seven (0.08 %) fetuses had Xp22.33/Yp11.32 microdeletions, ranging from 243 kb to 1.1 Mb, that comprised SHOX. The ultrasonic phenotypes differed among these fetuses, with three fetuses presenting abnormal bone development, one had labial-palatal deformity and strawberry head, two had an abnormal ultrasonic soft marker, and one had no abnormalities. After genetic counseling, onlyone couple underwent pedigree assessment, which confirmed the paternal origin of the microdeletion. This infant presented delayed speech development, whereas other three infants showed a typical postnatal development. In three cases, the parents chose to terminate the pregnancy. The ultrasonic phenotype of fetuses with Xp22.33/Yp11.32 microdeletions resulting in SHOX heterozygosity loss is variable. Prenatal CMA can quickly and effectively diagnose Xp22.33/Yp11.32 microdeletions and SHOX loss, which may help prenatal counseling.

The Effect of Resolution Level and Targeted Design in the Diagnostic Performance of Prenatal Chromosomal Microarray Analysis

Introduction: This study was performed to assess the optimal resolution for prenatal testing by array comparative genomic hybridization (aCGH), aiming to balance between maximum diagnostic yield and minimal detection of variants of uncertain significance (VOUS). Methods: This was a prospective study using data of 2,336 fetuses that underwent invasive prenatal diagnosis, and the samples were analyzed by aCGH. In total, six different aCGH platforms were studied; four different resolutions (0.18 Mb, 0.5 Mb, 1 Mb, and 2 Mb) and two platform designs (whole-genome [WG] and targeted). The results of these designs were compared based on their diagnostic yield and VOUS rate. The performance of the different designs was further analyzed according to indication for invasive testing. Results: The diagnostic yield of copy number variants increased with increasing level of analysis. The detection rates of clinically significant chromosomal abnormalities were almost the same across our targeted array designs; 7.2% with 0.18 Mb backbone/0.05 Mb versus 7.1% with 0.5 Mb backbone/0.05 Mb (p >0.05). However, a significant difference in the rate of VOUS was observed; 9.4% with 0.18 Mb backbone/0.05 Mb versus 6% with 0.5 Mb backbone/0.05 Mb (p <0.001). After analyzing the results across different indications for testing, we found that the application of non-targeted platform designs and lower levels of resolution analysis (such as 1 Mb WG or 0.5 MbL/1 MbG WG) would offer similar diagnostic yield in most cases with major congenital anomalies, with lower VOUS rates. However, the sample size for many indication groups was too small to extract robust associations. Conclusion: It appears that the targeted array platform with 0.5 Mb backbone resolution and 0.05 Mb on targeted gene-rich regions is optimal for routine chromosomal microarray analysis use in prenatal diagnosis. It may be beneficial to individualize the minimum resolution in specific referral indications as the indications for invasive prenatal testing may be quite heterogeneous.

Prenatal Chromosomal Microarray Analysis: Does Increased Resolution Equal Increased Yield?

Chromosomal microarray analysis (CMA) is considered a first-tier test for patients with developmental disabilities and congenital anomalies and is also routinely applied in prenatal diagnosis. The current consensus size cut-off for reporting copy number variants (CNVs) in the prenatal setting ranges from 200 Kb to 400 Kb, with the intention of minimizing the impact of variants of uncertain significance (VUS). Very limited data are currently available on the application of higher resolution platforms prenatally. The aim of this study is to investigate the feasibility and impact of applying high-resolution CMA in the prenatal setting. To that end, we report on the outcomes of applying CMA with a size cut-off of 20 Kb in 250 prenatal samples and discuss the findings and diagnostic yield and also provide follow-up for cases with variants of uncertain significance. Overall, 19.6% (49) showed one or more chromosomal abnormalities, with the findings classified as Pathogenic (P) or Likely Pathogenic (LP) in 15.6% and as VUS in 4%. When excluding the cases with known familial aberrations, the diagnostic yield was 12%. The smallest aberration detected was a 32 Kb duplication of the 16p11.2 region. In conclusion, this study demonstrates that prenatal diagnosis with a high-resolution aCGH platform can reliably detect smaller CNVs that are often associated with neurodevelopmental phenotypes while providing an increased diagnostic yield, regardless of the indication for testing, with only a marginal increase in the VUS incidence. Thus, it can be an important tool in the prenatal setting.

Chromosomal Microarray Analysis in Pregnancy Loss: Is It Time for a Consensus Approach?

ABSTRACT Affecting up to 10% to 15% of all clinically recognized pregnancies, pregnancy loss has many causes. Half of first-trimester losses come about due to chromosomal abnormalities and then decline in frequency through pregnancy, ultimately reaching a rate of 5% in stillbirths. Recurrent pregnancy loss occurs in 1% to 2% of couples, and identifying the genetic etiology of these losses can provide psychological benefits, eliminate other testing needs, and establish a risk of recurrence. As benefits of performing genetic testing on products of conception (POCs) are clear, various groups have published practice guidelines (American College of Obstetricians and Gynecologists, European Society of Human Reproduction and Embryology, American Society for Reproductive Medicine, and Royal College of Obstetricians and Gynaecologists). However, despite the consensus for the utility of testing on POCs, requirements for these tests vary. Most appropriate testing methodology, obstetric history, and gestational age are all variations that affect the benefit or utility of these tests. As there is a lack of consensus on how to use chromosomal microarray analysis (CMA) in assessment of POCs, this study assessed POC CMA data with available karyotype data and determined the positive CMA rate for POCs. The authors also included within this data set a comprehensive correlation of CMA correlations with pregnancy phenotype, gestational age, and prior prenatal screening results. Finally, the study also assessed the impact CMA results from early losses may have on clinical care. This cohort included 323 POC samples processed by the Brigham and Women's Hospital Center for Advanced Molecular Diagnostics in the Clinical Cytogenetics Laboratory over a consecutive 42-month period. Collected variables included estimated gestational age at time of pregnancy loss, maternal age, pregnancy phenotype results of any orthogonal testing on POC tissue, noninvasive prenatal screen results, CMA findings, and available parental karyotypes. All cases recorded gestational age except 1 sample lacking documentation. Categories of phenotypic data included lymphatic malformations, anatomical abnormalities of the fetus or placenta, twin or higher-level multiple gestations, environmental complications, amniotic fluid disorders, or the combined influence of any of the above. A lack of definitive phenotypic data excluded 3 cases from the analysis. Analyses of CMA results were categorized as normal, abnormal, or variants of uncertain significance (VUSs). The cases defined as normal had no identifiable clinically significant copy number variants, and abnormal cases were defined as pathogenic. Results of the study included gestational age for 322 of 323 cases, which was then used to determine the rate of fetal demise or miscarriage at different gestational ages in the cohort, with first-trimester losses at &lt;14 weeks (n = 230) and later losses defined as occurring at &gt;14 weeks gestational age (n = 92). The results demonstrated that frequency and genetic abnormality types (as identified by CMA) align closely with karyotype studies previously published. This means that an approximate half of the first-trimester loss cohort have a genetic abnormality, with trisomies as the most common finding. Very early losses tend to have a high positive rate of abnormalities (45.6%), which further supported CMA use in first-trimester losses. Inadvertent assessment and reporting of maternal metaphases were reduced, and yield of results improved with the implementation of CMA. Abnormal POC results may suggest balanced parental abnormalities, and follow-up parental testing in such cases is recommended. A need for additional studies exists to determine the parental follow-up studies yield. In conclusion, POC tissue genetic testing following pregnancy loss can aid in clinical management via identification of genetic etiologies, thereby refining recurrence risk. However, lack of consensus in terms of testing strategies and methodologies indicates a need for standardized methodology. This study demonstrated CMA results consistent with published karyotype studies established CMA analysis advantages over POC karyotype in all gestational ages. Even in early first-trimester losses, these results support the efficacy of CMA in POC testing.

Prenatal diagnosis in the fetal hyperechogenic kidneys: assessment using chromosomal microarray analysis and exome sequencing

Fetal hyperechogenic kidneys (HEK) is etiologically a heterogeneous disorder. The aim of this study was to identify the genetic causes of HEK using prenatal chromosomal microarray analysis (CMA) and exome sequencing (ES). From June 2014 to September 2022, we identified 92 HEK fetuses detected by ultrasound. We reviewed and documented other ultrasound anomalies, microscopic and submicroscopic chromosomal abnormalities, and single gene disorders. We also analyzed the diagnostic yield of CMA and ES and the clinical impact the diagnosis had on pregnancy management. In our cohort, CMA detected 27 pathogenic copy number variations (CNVs) in 25 (25/92, 27.2%) fetuses, with the most common CNV being 17q12 microdeletion syndrome. Among the 26 fetuses who underwent further ES testing, we identified 7 pathogenic/likely pathogenic variants and 8 variants of uncertain significance in 9 genes in 12 fetuses. Four novel variants were first reported herein, expanding the mutational spectra for HEK-related genes. Following counseling, 52 families chose to continue the pregnancy, and in 23 of them, postnatal ultrasound showed no detectable renal abnormalities. Of these 23 cases, 15 had isolated HEK on prenatal ultrasound. Taken together, our study showed a high rate of detectable genetic etiologies in cases with fetal HEK at the levels of chromosomal (aneuploidy), sub-chromosomal (microdeletions/microduplications), and single gene (point mutations). Therefore, we speculate that combined CMA and ES testing for fetal HEK is feasible and has good clinical utility. When no genetic abnormalities are identified, the findings can be transient, especially in the isolated HEK group.

Clinical outcomes of fetuses with chromosome 16 short arm copy number variants.

The short arm of chromosome 16 consists of several copy number variants (CNVs) that are crucial in neurodevelopmental disorders; however, incomplete penetrance and diverse phenotypes after birth aggravate the difficulty of prenatal genetic counseling. We screened 15,051 pregnant women who underwent prenatal chromosomal microarray analysis between July 2012 and December 2017. Patients with positive array results were divided into four subgroups based on the type of mutation identified on screening (16p13.3, 16p13.11, 16p12.2, and 16p11.2), and the maternal characteristics, prenatal examinations, and postnatal outcomes of different cases were reviewed. Chromosome 16 CNVs were identified in 34 fetuses, including four with 16p13.3 CNVs, 22 with 16p13.11 CNVs, two with 16p12.2 microdeletions, and six with 16p11.2 CNVs. Of the 34 fetuses, 17 delivered without early childhood neurodevelopmental disorders, three developed neurodevelopmental disorders during childhood, and 10 were terminated. Incomplete penetrance and variable expressivity make prenatal counseling challenging. Most cases with inherited 16p13.11 microduplication were reported to have normal development in early childhood, and we also report a few cases of de novo 16p CNVs without further neurodevelopmental disorders.

Receiving uncertain results from prenatal chromosomal microarray analysis: Women's decisions on continuation or termination of pregnancy.

Chromosomal microarray analysis (CMA) may detect variants of uncertain clinical significance (VUS) and susceptibility loci (SL) with incomplete penetrance for neurodevelopmental disorders. This qualitative study provides empirical data on women's experiences with receiving such findings in pregnancy and their decisions regarding continuation or termination of the pregnancy. Semi-structured interviews were conducted with women who received a VUS and/or SL from prenatal CMA in the last 2-4years and were analyzed using Grounded Theory. The vast majority of women recalled being stressed by the findings. All women sought further advice and information to be able to decide whether to continue or terminate their pregnancy. The three pregnancies that were terminated have in common a de novo SL with a 10%-20% penetrance. Similar reasoning (coping with uncertainty, the quest for a perfect child, and a chance for recurrence in future pregnancies) led different women to contradicting conclusions regarding their pregnancies. All women felt satisfied with their decisions. Although uncertain/probabilistic information commonly involves a psychological burden, it may also be perceived as valuable and actionable. Pre-test parental choice regarding the disclosure of such information could allow personalized utilization of advanced genomic tests in pregnancy.

An Investigation of the Etiologies of Non-Immune Hydrops Fetalis in the Era of Next-Generation Sequence-A Single Center Experience.

(1) Background: Numerous etiologies may lead to non-immune hydrops fetalis (NIHF). However, the causes remain unclear in half of NIHF cases following current standard assessment. The application of prenatal chromosomal microarray analysis (CMA) and exome sequencing (ES) can improve the identification of the etiologies. This study aimed to investigate the etiologies of NIHF in the era of next-generation sequence (NGS) following a unified prenatal work-up flow for diagnosis. (2) Methods: A retrospective analysis was conducted on NIHF cases that were collected prospectively to explore the underlying etiologies according to a unified prenatal diagnosis work-up flow at Shanghai First Maternity and Infant Hospital between Jan 2016 and Dec 2019. The medical records for all NIHF cases were reviewed, and the causes of NIHF were classified as confirmed (diagnostic), suspected, or unknown. (3) Results: Prenatal and postnatal medical records for a total of 145 NIHF cases were reviewed, 48.3% (70/145) of the cases were identified to be with confirmed etiologies, and 10.3% (15/145) with suspected etiologies. Among 85 cases with confirmed or suspected etiologies, 44.7% were diagnosed with genetic disorders, 20% with chylothorax/chyloascites diagnosed postnatally, 12.9% with fetal structural anomalies, 12.9% with fetal anemia, 7% (6 cases) with fetal arrhythmia, and 2.3% (2 cases) with placenta chorioangioma. In cases with genetic disorders, 8 aneuploidies were detected by CMA, and 30 cases had single-gene disorders identified by ES (29/30) or targeted gene panel (1/30). There were still 41.4% cases (60/145) with unknown causes after this unified prenatal diagnostic work-up flow. (4) Conclusions: In the era of NGS, the causes of NIHF were identified in 58.6% of cases, with genetic disorders being the most common ones. NGS is helpful in determining the genetic etiology of NIHF when CMA results cannot explain NIHF, but 41.4% of cases were still with unknown causes under the unified prenatal diagnostic work-up flow in this single-center study.

Prenatal diagnosis and genetic counseling of an inherited Xq24q25 deletion associated with normal phenotype

BackgroundCopy number variants (CNVs) are an important source of normal and pathogenic genome variations. CNVs identified in prenatal cases need careful considerations and correct interpretation if those are harmless or harmful variants from the norm.Case presentation A 28-year-old, gravida 1, para 0, woman underwent amniocentesis at 17 weeks of gestation because the noninvasive prenatal testing (NIPT) results revealed a 9.8 Mb deletion from Xq24 to Xq25. GTG-banding karyotype analysis was performed on cultured amniocytes. Chromosomal microarray analysis (CMA) on uncultured amniocytes was performed.ResultsChromosomal GTG-banding of the cultured amniocytes revealed a karyotype of 46,XX. CMA detected a 9.5-Mb chromosomal deletion in the region of Xq24q25 (arr[GRCh37] Xq24q25(118,975,436_128,444,692) × 1).ConclusionThe present report highlights that an integration of prenatal ultrasound, NIPT, karyotype analysis, CMA and genetic counseling is helpful for the prenatal diagnosis of chromosomal deletions/duplications.

Should prenatal chromosomal microarray analysis be offered for isolated ventricular septal defect? A single-center retrospective study from China.

ObjectiveTo evaluate the utility of chromosomal microarray analysis (CMA) in fetuses with isolated ventricular septal defect (VSD) and to explore the favorable factors for predicting spontaneous closure of defects.MethodsThe study included 436 singleton pregnancies seen at a referral prenatal diagnosis center, between January 2016 and May 2020, of which 168 fetuses with isolated VSD were diagnosed in the prenatal setting. VSD was classified as an isolated VSD whether it had ultrasound soft markers or not. All patients underwent testing employing quantitative fluorescent polymerase chain reaction (QF-PCR) and CMA as the first-line genetic detection strategies, mainly in amniotic fluid and umbilical blood samples. Rates of chromosomal abnormalities were compared by subgroups of isolated VSD (muscular or perimembranous). Binary logistic regression analysis was performed to predict the independent determinants of spontaneous closure by 2 years.ResultsOverall, the CMA identified clinically significant copy number variations (CNVs) in 7/168 (4.2%) fetuses and variants of unknown significance (VOUS) in 15/168 (8.9%). Muscular and perimembranous VSDs were found in 53.6 and 46.4%, respectively. Clinically significant relevant subchromosomal aberrations were revealed in seven (9.0%) perimembranous VSDs compared with none in 90 muscular defects (P < 0.01). The median initial size of the defect in the muscular VSDs was 2.2(1.8–2.7) mm, as compared to that of 2.8 (2.2–3.2) mm in the perimembranous VSDs group (p = 0.000). In muscular vs. perimembranous VSDs, spontaneous closure occurred more frequently and earlier [40.0 vs. 15.4% in utero (p = 0.000), 61.1 vs. 30.8% at 1-year (p = 0.000), and 75.6 vs. 42.3% at 2-year (P = 0.000)]. Postnatal surgical closure was warranted in 4/90 (4.4%) of the infants with muscular VSDs, as compared to 29/71 (40.8%) with perimembranous defects (p = 0.000). Furthermore, isolated muscular type VSD, smaller defect size, and maternal age of less than 35 years are all positive predictors of spontaneous closure of the defects.ConclusionThis study highlighted the value of microarray for unbalanced subchromosomal abnormalities in fetuses with isolated VSD, particularly in the perimembranous defects. The detection of an isolated muscular VSD prenatally may be considered a benign or likely benign finding; in contrast, for perimembranous VSD, a prenatal CMA should be offered.

Prenatal diagnosis and genetic counseling of an inherited unbalanced chromosome abnormalities in a Chinese family

BackgroundUnbalanced chromosome abnormalities (UBCA) are either gains or losses or large genomic regions, but the affected person is not or only minimally clinically affected. Copy number variants (CNVs) are an important source of normal and pathogenic genome variations. CNVs and UBCA identified in prenatal cases need careful considerations and correct interpretation if those are harmless or harmful variants from the norm.Case presentationA 25-year-old, gravida 1, para 0, woman underwent amniocentesis at 18 weeks of gestation because the noninvasive prenatal testing (NIPT) results revealed a 6.8 Mb duplication from 2q11.1 to 2q11.2. Chromosomal microarray analysis (CMA) was performed on uncultured amniocytes. GTG-banding karyotype analysis on cultured amniocytes was performed.ResultsChromosomal GTG-banding of the cultured amniocytes revealed a karyotype of 46,XX. CMA detected a 6.8-Mb chromosomal duplication in the region of 2q11.1q11.2 (arr[GRCh37] 2q11.1q11.2(95,327,873_102,088,148)x3).ConclusionChromosomal microdeletions and microduplications are difficult to detect by conventional cytogenetics, combination of prenatal ultrasound, karyotype analysis, NIPT, CMA and genetic counseling is helpful for the prenatal diagnosis of UBCA and chromosomal microdeletions/microduplications.

Prenatal diagnosis and genetic counseling of a 10p11.23q11.21 duplication associated with normal phenotype

BackgroundCopy number variants (CNVs) are an important source of normal and pathogenic genome variations. Unbalanced chromosome abnormalities (UBCA) are either gains or losses or large genomic regions, but the affected person is not or only minimally clinically affected. CNVs and UBCA identified in prenatal cases need careful considerations and correct interpretation if those are harmless or harmful variants from the norm.Case presentationA 24-year-old, gravida 1, para 0, woman underwent amniocentesis at 17 weeks of gestation because the noninvasive prenatal testing (NIPT) results revealed a 12.4 Mb duplication from 10p11.2 to 10q11.2. GTG-banding karyotype analysis was performed on cultured amniocytes. Chromosomal microarray analysis (CMA) on uncultured amniocytes was performed.ResultsChromosomal GTG-banding of the cultured amniocytes revealed a karyotype of 46,XX,dup(10)(p11.2q11.2). CMA detected a 12.5-Mb chromosomal duplication in the region of 10p11.23q11.21 (arr[GRCh37] 10p11.23q11.21(30,345,109_42,826,062) × 3).ConclusionThe present report enlarges the known UBCA region 10p11.22-10q11.22 to 10p11.23-10q11.22. Also it highlights that an integration of prenatal ultrasound, NIPT, karyotype analysis, CMA and genetic counseling is helpful for the prenatal diagnosis of chromosomal deletions/duplications.