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Objective This study aimed to determine the diagnostic yield of chromosomal microarray analysis (CMA) performed in cases of fetal abnormalities detected during the third trimester of pregnancy. Study Design A retrospective review of medical records was conducted for women who underwent amniocentesis at or beyond 28 weeks of gestation between January 2017 and February 2023. CMA results of pregnancies with abnormal sonographic findings not detected before 28 weeks were included. Results A total of 482 fetuses met the inclusion criteria. The average maternal age was 31.3 years, and the average gestational age at amniocentesis was 32.3 weeks. The overall diagnostic yield of CMA was 6.2% (30 clinically significant copy number variations [CNVs]). The yield was 16.4% in cases with two or more fetal malformations, while cases with a single anomaly revealed a diagnostic yield of 7.3%. Cases presenting isolated polyhydramnios or isolated fetal growth restriction had a lower yield of 9.3 and 5.4%, respectively. Of the 30 clinically significant cases, 19 (or 63.4%) exhibited recurrent CNVs. The remaining 11 cases (or 36.6%) presented unique CNVs. The theoretical yield of Noninvasive Prenatal Testing (NIPT) in our cohort is 2% for aneuploidy, which implies that it could potentially miss up to 70% of the significant findings that could be identified by CMA. In 80% of the fetuses (or 24 out of 30) with clinically significant CNVs, the structural abnormalities detected on fetal ultrasound examinations corresponded with the CMA results. Conclusion The 6.2% detection rate of significant CNVs in late-onset fetal anomalies confirms the value of CMA in third-trimester amniocentesis. The findings underscore the necessity of CMA for detecting CNVs potentially overlooked by NIPT and emphasize the importance of thorough genetic counseling. Key Points CMA yields 6.2% for third-trimester anomalies. NIPT may miss 70% of CMA findings. Ultrasound matched 80% of CMA results. [ABSTRACT FROM AUTHOR]

Purpose: To analyze the risk for clinically significant microarray aberrations in pregnancies with polyhydramnios.Methods: Data from all chromosomal microarray analyses (CMA) performed due to polyhydramnios between January 2013 and December 2019 were retrospectively obtained from the Ministry of Health Database. The rate of clinically significant (pathogenic and likely pathogenic) CMA findings in isolated and non-isolated polyhydramnios cohorts was compared to a local control group of 5541 fetuses with normal ultrasound, in which 78 (1.4%) abnormal results were demonstrated. Subgroup analyses were performed by the degree of polyhydramnios, week of diagnosis, maternal age, and the presence of additional sonographic anomalies.Results: In the isolated polyhydramnios cohort, 19/623 (3.1%) clinically significant CMA aberrations were noted, a significantly higher rate compared to the control population. However, the risk for abnormal CMA results in the 158 cases with mild polyhydramnios (AFI 25-29.9, or maximal vertical pocket 8-11.9 cm) did not significantly differ from pregnancies with normal ultrasound. Of 119 cases of non-isolated polyhydramnios (most frequently associated with cardiovascular (26.1%) and brain (15.1%) anomalies), 8 (6.7%) abnormal CMA findings were noted, mainly karyotype-detectable.Conclusion: Mild polyhydramnios was not associated with an increased rate of clinically significant microarray results, compared to pregnancies with normal ultrasound. An extensive anatomical sonographic survey should be performed in pregnancies with polyhydramnios, with consideration of fetal echocardiography. [ABSTRACT FROM AUTHOR]

Objective: To explore the risk for abnormal chromosomal microarray analysis (CMA) findings in pregnancies with oligohydramnios. Methods: Data from all CMA analyses performed due to oligohydramnios between 2013 and 2017 were retrospectively obtained from the Israeli Ministry of Health database. The rate of clinically significant (pathogenic and likely pathogenic) findings was compared to a local cohort of pregnancies with normal ultrasound, yielding a 1.4% rate of abnormal CMA results. In addition, a search was conducted through the PubMed database addressing the issue. Results: Fifty CMA analyses were performed due to oligohydramnios. The 2% risk for clinically significant CMA finding in pregnancies with oligohydramnios did not differ from the control population of 5541 pregnancies with normal ultrasound – relative risk (RR) 1.4 [95% confidence interval (CI) 0.2–10.2]. Literature search yielded 394 titles, of which four relevant articles were selected, all using fetal karyotyping. Conclusion: There is yet insufficient evidence to support invasive prenatal testing in pregnancies with isolated oligohydramnios. [ABSTRACT FROM AUTHOR]

Objective: The objective of this study is to examine the frequency of abnormal Chromosomal Microarray (CMA) analyses among fetuses with isolated non-visualization of fetal gallbladder.Methods: Data from CMA analyses performed due to isolated non-visualization of fetal gallbladder between January 2013 and September 2016 were retrospectively acquired from a computerized database of the Israeli Ministry of Health. The results were compared with the rate for clinically significant CMA findings in general population, based on a large cohort of 5541 pregnancies undergoing CMA due to maternal request, and a systematic review of 9272 cases with normal ultrasound.Results: Of 45 pregnancies with isolated non-visualization of fetal gallbladder, CMA testing yielded one (2.22%) gain-of-copy-number variant at 16p11.2, categorized as "pathogenic". In addition, one finding of unknown significance was demonstrated. The risk for clinically meaningful CMA findings among pregnancies with isolated absent gallbladder was not significantly increased compared to control population.Conclusions: To the best of our knowledge, this study is the first report describing the rate of pathogenic CMA results in fetuses with isolated non-visualization of fetal gallbladder. The results, in conjunction with previous studies, show that the risk for abnormal CMA results in pregnancies diagnosed with non-visualized gallbladder is not significantly different from pregnancies with normal ultrasound. [ABSTRACT FROM AUTHOR]

Objective: To examine the risk for abnormal chromosomal microarray analysis (CMA) results among fetuses with an apparently isolated pelvic kidney. Methods: Data from all CMA analyses performed due to an isolated pelvic kidney reported to the Israeli Ministry of Health between January 2013 and September 2016 were retrospectively obtained. Risk estimation was performed comparing the rate of abnormal observed CMA findings to the general population risk, based on a systematic review encompassing 9272 cases and on local data of 5541 cases. Results: Of 120 pregnancies with an isolated pelvic kidney, two gain-of-copy number variants suggesting microduplication syndromes were demonstrated (1.67%). In addition, three variants of unknown significance were detected (2.5%). Conclusion: The risk for clinically significant CMA findings among pregnancies with an isolated single pelvic kidney was not significantly different compared to both control populations. The results of our study question the practice of routine CMA analysis in fetuses with an isolated pelvic kidney. [ABSTRACT FROM AUTHOR]

Objective: To determine the rate of chromosomal cytogenetic abnormalities in fetuses with late onset abnormal sonographic findings. Design: Retrospective cohort of women who underwent amniocentesis at or beyond 23 weeks of gestation, for fetal karyotype and chromosomal microarray analysis, indicated due to late onset abnormal sonographic findings. Results: All 103 fetuses had a normal karyotype. Ninety-five women also had chromosomal microarray analysis (CMA) performed. The detection rate of abnormal CMA (5/95, 5.3%) was similar to that of women who underwent amniocentesis due to abnormal early onset ultrasound findings detected at routine prenatal screening tests during the first or early second trimester (7.3%, P=0.46) and significantly higher than that for women who underwent amniocentesis and CMA upon request, without a medical indication for CMA (0.99%, P<0.0001). Conclusions: Late onset sonographic findings are an indication for amniocentesis, and if performed, CMA should be applied to evaluate fetuses with late onset abnormal sonographic findings. [ABSTRACT FROM AUTHOR]

Objective: To examine the risk for clinically significant chromosomal microarray analysis (CMA) among fetuses with apparently isolated horseshoe kidney.Methods: Data from all CMA analyses performed due to isolated horseshoe kidney reported to the Israeli Ministry of Health between January 2013 and September 2016 were retrospectively obtained from a computerized database. Risk estimation was performed comparing the rate of abnormal CMA findings to the general population, based on a systematic review encompassing 9272 pregnancies with normal ultrasound, and local data cohort of 5541 pregnancies undergoing CMA due to maternal request.Results: Of 82 pregnancies with isolated horseshoe kidney, one loss-of-copy-number variant compatible with 16p13.11 microdeletion syndrome was demonstrated (1.2%). In addition, two variants of unknown significance (VOUS) were detected (2.4%). The relative risk for pathogenic CMA findings among pregnancies with isolated single horseshoe kidney was not significantly different from the control population (1.03-1.39%).Discussion: To our best knowledge, our study is the first report describing the rate of clinically significant CMA findings in fetuses with isolated horseshoe kidney. The detection of one pathogenic CMA findings in our cohort implies that the value of CMA analysis in such pregnancies is similar to the general population. [ABSTRACT FROM AUTHOR]

ABSTRACT This retrospective cohort study aimed to define the optimal Regions of Homozygosity (ROH) size cut‐offs for prediction of morbidity, based on 13 483 Chromosomal Microarray Analyses (CMA). Receiver operating characteristic (ROC) curves were generated, and area under the curve (AUC) was used to assess the predictive capability of total ROH percentage (TRPS), ROH number and ROH segment size in distinguishing between healthy (n=6,196) and affected (n=6,839) cohorts. The metrics were examined for telomeric and interstitial segments, distinct TRPS categories, and across different ancestral origins. ROH segments were identified in 13 035 samples (96.7%), encompassing 66 710 ROH segments. Significant differences in TRPS and ROH segment size were observed between healthy and affected cohorts (p=0.012 and p < 0.001, respectively). However, no clinically significant thresholds could be established based on ROC curves for TRPS and ROH number per sample, as well as for ROH size (AUC 0.64, 0.55, and 0.62, respectively, Figure 1). The same was noted for telomeric versus interstitial locations, various origins, and subcategories of TRPS. In conclusion, this study highlights the complexity of ROH interpretation and emphasizes the importance of tailored reporting strategies in clinical practice. Our findings underscore the need for context‐specific reporting guidelines and further research, particularly in consanguineous populations. [ABSTRACT FROM AUTHOR]

Objective: To examine the effect of maternal age on the rate of clinically significant chromosomal microarray analysis results in pregnancies with abnormal maternal serum screening and to establish the residual risk for abnormal microarray findings after omitting noninvasive prenatal testing (NIPT)-detectable aberrations in pregnancies with abnormal maternal serum screening.Methods: This retrospective study included all chromosomal microarray analysis tests performed in pregnancies with abnormal maternal serum screening and normal ultrasonogram results over the years 2013-2021. The rate of clinically significant (pathogenic and likely pathogenic) chromosomal microarray analysis findings was compared with a local control cohort of 7,235 pregnancies with normal maternal serum screening and ultrasonogram results, stratified by maternal age. Calculation of residual risk for clinically significant chromosomal microarray analysis results after normal NIPT was performed by omission of common NIPT-detectable anomalies. Systematic review for studies examining the yield of chromosomal microarray analysis in pregnancies with abnormal maternal serum screening was performed from inception to October 2021, with no time or language restrictions.Results: Of the 559 amniocenteses performed due to abnormal maternal serum screening, 21 (3.8%; 95% CI 2.4-5.7%) clinically significant chromosomal microarray analysis results were found. The residual risk for chromosomal microarray analysis aberrations after theoretically normal NIPT was estimated to be 2.0% (95% CI 1.1-3.6%) (1/50) and was significantly higher for women younger than age 35 years with abnormal maternal serum screening, compared with women with low-risk pregnancies. Systematic review yielded six articles encompassing 4,890 chromosomal microarray analysis results in pregnancies with abnormal maternal serum screening, demonstrating 2.3% residual risk for chromosomal microarray analysis anomalies after theoretically normal NIPT.Discussion: Clinically significant chromosomal microarray analysis findings can be found in 1 of every 50 pregnancies with high-risk maternal serum screening after theoretically normal NIPT, implying that invasive testing and not NIPT should be recommended in such pregnancies. In addition, NIPT use as a first-tier screening modality instead of maternal serum screening would miss pregnancies at increased risk not only for common autosomal trisomies but for additional chromosomal microarray analysis-detectable disorders. [ABSTRACT FROM AUTHOR]

Objective: To examine the risk of clinically significant chromosomal microarray analysis findings in fetuses with nuchal translucency from 3.0-3.4 mm. In addition, we aimed to define the yield of noninvasive prenatal testing (NIPT) in such pregnancies.Methods: This retrospective cohort study included results of all chromosomal microarray analysis tests performed owing to a nuchal translucency measurement from 3.0-3.4 mm, without ultrasonographic anomalies, retrieved from the Israeli Ministry of Health computerized database. Rates of clinically significant (pathogenic and likely pathogenic) microarray findings were compared with a previously published local control population, encompassing 2,752 fetuses with normal ultrasound findings and nuchal translucency less than 3.0 mm.Results: Overall, 619 chromosomal microarray analyses were performed owing to isolated nuchal translucency from 3.0-3.4 mm. Of these, 29 (4.7%) cases had clinically significant copy number variants, a significantly higher risk compared with control-group pregnancies (relative risk 3.3, 95% CI 2.6-7.2). Divided by tenths of millimeters, the risk for abnormal chromosomal microarray analysis findings remained significantly increased, except for the subgroup of 198 fetuses with nuchal translucency measurements of 3.0 mm. Noninvasive prenatal testing for the five common chromosome aneuploidies would have missed 41.4% of the abnormal copy number variants-1.9% of overall cases, or 1 in 52 fetuses with nuchal translucency from 3-3.4 mm. Genome-wide NIPT, as well as traditional karyotyping, could have missed an abnormal finding in 9 of 619 (1.5%), or 1 in 69 fetuses.Conclusion: Our outcomes show that the rate of abnormal chromosomal microarray analysis findings in fetuses with nuchal translucency from 3.1-3.4 mm is significantly higher compared with fetuses with normal ultrasound findings. [ABSTRACT FROM AUTHOR]