Submicroscopic Chromosomal Aberrations Research Articles

Partial trisomy 9p and partial monosomy 7p of an infant inherited from maternal balanced translocation: a case report

BackgroundSubchromosomal deletions and duplications are the leading cause of congenital malformations and mental retardation in children. With the recent clinical application of genomic microarrays in the evaluation of patients with developmental delays and congenital malformations, it has led to the discovery of several new microdeletion and microduplication syndromes. However, there are no published reports involving patients with both microduplications in the 9p21.1-p24.3 region and microdeletions in the 7p22.1-p22.3 region.Case presentationWe report an infant with an autosomal abnormality confirmed by conventional karyotype combined with copy number variations sequencing (CNV-seq), showing the patient with an unbalanced translocation. The karyotype of the patient was 46, XX, der (7)t (7;9) (p22; p21) and CNV-seq results showed an approximately 32.34-Mb duplication in 9p21.1-p24.3 (200000-32540000) and an approximately 3.3-Mb deletion in 7p22.2-p22.3 (40000-3340000).ConclusionsThe patient carried an unbalanced translocation 46, XX, der (7)t (7;9) (p22; p21) derived from her mother. The clinical presentation is closely related to the size and position of the missing and duplicated chromosomes. To our knowledge, the simultaneous occurrence of de novo partial trisomy 9p(9p21.1-p24.3) and partial monosomy 7p (7p22.2-p22.3) has not previously been reported up until now. The present study additionally demonstrated that CNV-seq combined with karyotype is able to reliably detect unbalanced submicroscopic chromosomal aberrations.

Prenatal detection of chromosomal abnormalities and copy number variants in fetuses with congenital gastrointestinal obstruction

BackgroundCongenital gastrointestinal obstruction (CGIO) mainly refers to the stenosis or atresia of any part from the esophagus to the anus and is one of the most common surgical causes in the neonatal period. The concept of genetic factors as an etiology of CGIO has been accepted, but investigations about CGIO have mainly focused on aneuploidy, and the focus has been on duodenal obstruction. The objective of this study was to evaluate the risk of chromosome aberrations (including numeric and structural aberrations) in different types of CGIO. A second objective was to assess the risk of abnormal CNVs detected by copy number variation sequencing (CNV-seq) in fetuses with different types of CGIO.MethodsData from pregnancies referred for invasive testing and CNV-seq due to sonographic diagnosis of fetal CGIO from 2015 to 2020 were obtained retrospectively from the computerized database. The rates of chromosome aberrations and abnormal CNV-seq findings for isolated CGIOs and complicated CGIOs and different types of CGIOs were calculated.ResultsOf the 240 fetuses with CGIO that underwent karyotyping, the detection rate of karyotype abnormalities in complicated CGIO was significantly higher than that of the isolated group (33.8% vs. 10.8%, p < 0.01). Ninety-three cases with normal karyotypes further underwent CNV-seq, and CNV-seq revealed an incremental diagnostic value of 9.7% over conventional karyotyping. In addition, the incremental diagnostic yield of CNV-seq analysis in complicated CGIOs (20%) was higher than that in isolated CGIOs (4.8%), and the highest prevalence of pathogenic CNVs/likely pathogenic CNVs was found in the duodenal stenosis/atresia group (17.5%), followed by the anorectal malformation group (15.4%). The 13q deletion, 10q26 deletion, 4q24 deletion, and 2p24 might be additional genetic etiologies of duodenal stenosis/atresia.ConclusionsThe risk of pathogenic chromosomal abnormalities and CNVs increased in the complicated CGIO group compared to that in the isolated CGIO group, especially when fetuses presented duodenal obstruction (DO) and anorectal malformation. CNV-seq was recommended to detect submicroscopic chromosomal aberrations for DO and anorectal malformation when the karyotype was normal. The relationship between genotypes and phenotypes needs to be explored in the future to facilitate prenatal diagnosis of fetal CGIO and yield new clues into their etiologies.

Prenatal diagnosis of Cri-du-Chat syndrome with concomitant distal trisomy 10q syndrome in one fetus with ultrasound anomalies

ObjectiveThe aim of this work was to characterize the genetic abnormalities and prenatal diagnosis indications in one fetus with Cri-du-Chat syndrome with codependent 10q24.2-q26.3 duplication in prenatal screening. Materials and methodsA 31-year-old woman had a second trimester serum screening that indicated the fetus was at low risk. During this pregnancy, the woman underwent amniocentesis at 18+4 weeks' gestation because of adverse fertility history and nuchal fold thickening. Cytogenetic analysis and next-generation sequencing analysis were simultaneously performed to provide genetic analysis of fetal amniotic fluid. According to abnormal results, parental chromosome karyotype of peripheral blood was performed to analysis. ResultsCNV-seq detected a 14.00 Mb deletion at 5p15.33-p15.2 and a 34.06 Mb duplication at 10q24.2-q26.3 in the fetus. Cytogenetic analysis of the fetus revealed a karyotype of 46, XY, der(5) t(5;10) (p15.2;q26.3). The karyotype of pregnant women was 46,XX,t(5;10) (p15.2;q24.2). The pregnancy was subsequently terminated after sufficient informed consent. ConclusionThis is the first study that reports prenatal diagnosis of a Cri-du-Chat syndrome with concomitant 10 q24.2-q26.3 duplication. Adverse pregnancy history has to be as an important indicator for prenatal diagnosis, and the genetic factors of abnormal pregnancy should be identified before next pregnancy. Nuchal fold thickening is closely related to fetal abnormalities. Combined with ultrasonography, the use of CNV-seq will improve the diagnosis of submicroscopic chromosomal aberrations in fetuses with congenital anomalies.

Karyotyping and Chromosomal Microarray Analysis in Women Requesting Amniocentesis for Isolated Sonographic Soft Markers or Advanced Maternal Age.

Background:Chromosomal microarray analysis (CMA) has gained acceptance in prenatal diagnosis, gradually replacing the traditional cytogenetic analysis following amniocentesis or chorionic villi sampling due to its higher resolution than traditional cytogenetics.Objctive:The present study investigated the prevalence of major and sub-chromosomal abnormalities in fetuses with isolated ultrasound findings during routine anatomy scan or pregnancies of advanced maternal age after maternal request without medical indication.Methods:Total number of 126 cases were included in total, consisted of two groups; the first group with isolated sonographic soft markers (84 fetuses) and the second group of advanced maternal age (42 fetuses). The group of isolated sonographic markers was further divided per anatomical system affected. The prevalence of genetic aberrations via QF-PCR and CMA was noted.Results:Clinically significant genetic abnormalities were detected in 12% of the first and 7% of cases in the second group. Interestingly, 40% and 67% of abnormal cases in the first and second group respectively, were identified only after CMA, and they would have missed diagnosis with standard karyotype or QF-PCR alone. Most genetic aberrations were detected in fetuses with findings in the central nervous, craniofacial, cardiovascular, and musculoskeletal system. Sub-microscopic chromosomal aberrations identified only after CMA were gathered in cases with short long bones and in one case with ventriculomegaly.Conclusion:Even in pregnancies with a first trimester screening low risk result, the risk of identifying a clinically significant CMA aberration is considerable, when an isolated sonographic marker is identified later on in pregnancy or maternal age is advanced.

Detection of submicroscopic chromosomal aberrations by chromosomal microarray analysis for the prenatal diagnosis of central nervous system abnormalities.

BackgroundCentral nervous system (CNS) abnormalities are a group of serious birth defects associated with high rates of stillbirths, infant death, or abnormal development, and various disease‐causing copy number variations play a much more important role in the etiology of CNS abnormalities. This study intends to present a retrospective study of the prenatal diagnosis and the pregnancy outcome of fetuses diagnosed with CNS abnormalities, and evaluate the clinical value of chromosomal microarray analysis (CMA) in prenatal diagnosis of CNS abnormalities.MethodsA total of 356 fetuses with CNS abnormalities with or without other ultrasound abnormalities subjected to invasive prenatal diagnosis at the first affiliated hospital of Air Force Medical University from January 2015 to August 2018. All cases have performed both karyotyping and CMA concurrently, but 20 fetuses with chromosome aneuploidy were excluded in the current study.ResultsThe CMA identified pathogenic copy number variants (pCNVs) in 27/336 (8.03%) fetuses, likely pCNVs in 8/336 (2.38%) fetuses, and variants of unknown significance (VOUS) in 11/336 (3.27%) fetuses. A total of 222 cases had single CNS abnormalities and the pCNVs detection rate was 5.86% (13/222), the remaining 114 cases including CNS abnormalities plus other structural abnormalities, ultrasonographic soft markers and two or more CNS abnormalities, the pCNVs detection rate was 12.3% (14/114).ConclusionsFetuses with CNS abnormalities have a higher risk of chromosomal abnormalities, our study showed that CNVs play an important role in the etiology of CNS abnormalities. The application of CMA could increase the detection rate of pCNVs causing CNS abnormalities.

Algorithm for the diagnosis of patients with neurodevelopmental disorders and suspicion of a genetic syndrome

The wide range of chromosome aberrations seen in neurodevelopmental disorders may not always be characterized by means of a chromosome analysis. The objective of this study was to determine the genetic etiology of these disorders in patients with congenital neurological conditions and clinical suspicion of a genetic disorder using a clinical and molecular testing algorithm. Among 111 studied children, 71 showed submicroscopic chromosome aberrations associated with microdeletion/microduplication syndromes: DiGeorge (22 cases), Prader-Willi (26 cases), Angelman (2 cases), WilliamsBeuren (17 cases), Smith-Magenis (1 case), Miller-Dieker (1 case), and cri du chat syndrome (1 case). Additionally, a de novo trisomy 17p12p11.2 due to an unbalanced insertion into 5p13.1 was identified in a 3-year-old child. In most cases, the use of a clinical method together with molecular techniques, such as fluorescence in situ hybridization, has allowed to make an accurate diagnosis in patients and/or families with neurodevelopmental disorders.

Prenatal diagnosis of submicroscopic chromosomal aberrations in fetuses with congenital cystic adenomatoid malformation by chromosomal microarray analysis

Objectives To explore the copy number variations (CNVs) of fetal congenital cystic adenomatoid malformation (CCAM). Methods Fetuses with CCAM were investigated by karyotypes and chromosomal microarray analysis (CMA). The cases were classified as isolated or CCAM with additional structural anomalies. The pregnancy outcome and neonatal prognosis were reported after the follow-up investigation. Results The karyotypes of 43 fetuses were analyzed and no abnormal karyotype was detected. Thirty-seven cases were further tested using CMA. The CMA identified pathogenic CNVs in three fetuses with a pathogenic detection rate of 8.1%. Well-known microdeletion or microduplication syndromes, including RCAD syndrome, HNPP, and CMT1A were identified, among which HNPP and CMT1A were incidental findings. After excluding two incidental findings, there were no pathogenic CNVs in isolated CCAM. There were no significant differences in pathogenic CNVs between isolated CCAM and CCAM with additional structural anomalies (0%, 0/31 versus 16.7%, 1/6, p=.162). Nearly half of the patients (53.8%, 14/26) underwent surgery after birth with good postoperative recoveries while the remaining half patients were spontaneous regression or asymptomatic. Conclusions The results demonstrated the value of CMA in the prenatal diagnosis of CCAM. CCAM associated with other structural defects enhanced the frequency of pathogenic CNVs while isolated CCAM may not be associated with an increase in the prevalence of pathogenic CNVs. CCAMs have an overall good prognosis.

Complex cytogenetic research of cryptic chromosomal aberrations in patients with multiple myeloma

Background . Multiple myeloma (MM) is a malignant lymphoproliferative B-cell disease characterization by clonal proliferation of plasma cells in the bone marrow and beyond its borders. Currently, a wide range of cytogenetic anomalies and molecular-biological parameters are studied as prognostic factors.Objective: a comparative study of the frequency, features and clinical significance of chromosomal abnormalities in MM by conventional cytogenetic and fluorescent in situ hybridization (FISH) methods.Materials and methods . 77 patients with MM, which admitted in N.N. Blokhin National Medical Research Center of Oncology, were included in the study from 2016 to 2017.Results . Chromosomal alterations were detected only in one case (1/77) by conventional cytogenetic method G-banding. However cytogenetic aberrations were revealed in 26 % of cases (20/77) using FISH. Deletions of different regions of chromosomes, indicating the possible presence of a hypodiploid clone or loss of some regions, were found in one patient in the second FISH analysis after 6 months. In the cohort of patients with chromosomal abnormalities (n = 20) a partial trisomy 11q, a deletion of the region q32 of the chromosome 14, a translocation t(4;14)(p16;q32) and IGHV gene rearrangement were determined in 30 % (6/20) as sole anomalies. Two or more cytogenetic aberrations were identified in the remaining 14 patients. Our study confirms that chromosomal abnormalities are more likely detected at later stages of MM (IA и IIA – 0 %, IIIA и IIIВ – 27 and 47 % respectively).Conclusion . FISH allows to detect chromosomal changes in tumor plasma cells regardless of the mitosis phase. In MM, it becomes particularly important in connection with low proliferative activity of plasma cells. Additionally, in the fourth of MM patients in the study submicroscopic chromosomal aberrations were discovered using FISH. The improvement of the probe panel and the widespread use of locus specific FISH don’t replace G-banding that allows to see damages of all chromosomes at once.

Chromosomal abnormalities and copy number variations in fetal ventricular septal defects

BackgroundThis study aimed to evaluate the applicability of chromosomal microarray analysis (CMA), rather than traditional chromosome analysis, in prenatal diagnosis of ventricular septal defects (VSDs) for superior prenatal genetic counseling and to reveal a potential correlation between submicroscopic chromosomal aberrations and VSDs.ResultsAmong the 151 VSD cases, 79 (52.3%) had isolated defects and 72 (47.7%) had additional ultrasound anomalies. Karyotype analysis identified 16 chromosomal abnormalities. Besides the 14 cases of chromosome abnormalities consistent with karyotype analysis, CMA identified an additional 20 cases (13.2%) of abnormal copy number variations (CNVs), of which 13 were pathogenetic CNVs, 5 were variations of uncertain clinical significance (VOUS) and 2 were benign CNVs. The detection rate of pathogenic CNVs in non-isolated-VSDs was significantly higher than that in isolated-VSDs (36.1% (26/72) vs. 1.3% (1/79), p = 0.001). We also found that CMA results indicating pathogenic abnormalities affected the rate of pregnancy termination.ConclusionsThis study showed that CMA combined with cytogenetic analysis is particularly effective in identifying CNVs in fetuses with VSDs and can have an effect on obstetrical outcomes. The elucidation of the etiology of VSDs suggested that gene mutations or other factors may be implicated.

Clinical value of chromosomal microarray analysis in prenatally diagnosed dextro-transposition of the great arteries

Objectives: To evaluate the usefulness of chromosomal microarray analysis (CMA) in fetuses with dextro-transposition of the great arteries (d-TGA).Methods: Thirty-two fetuses with d-TGA were examined for submicroscopic copy number variations (CNVs) using CMA.Results: Among the 32 d-TGA fetuses, 23 had isolated lesions (71.9%) and nine had other cardiac or extracardiac anomalies (28.1%). CNVs were detected in 16/32 (50%) of the fetuses, including benign CNVs detected in nine fetuses (28.1%), pathogenic CNVs detected in three fetuses (9.4%), and variants of unknown significance (VOUS) detected in four fetuses (12.5%). There was no significant difference in the detection rates of pathogenic CNVs between the isolated and nonisolated groups. All four VOUS were found in the nonisolated group.Conclusion: CMA might be an effective tool for identifying submicroscopic chromosomal aberrations in fetuses with d-TGA.

Frequency of Submicroscopic Chromosomal Aberrations in Pregnancies Without Increased Risk for Structural Chromosomal Aberrations: Systematic Review and Meta-analysis

(Abstracted from Ultrasound Obstet Gynecol 2018;51:445–452) Chromosomal microarray is currently recommended for women with fetal structural anomalies. However, questions remain as to whether such testing is justifiable in pregnancies without increased risk for unbalanced structural chromosomal aberrations.

Novel 1q22-q23.1 duplication in a patient with lambdoid and metopic craniosynostosis, muscular hypotonia, and psychomotor retardation

Craniosynostosis (CS) refers to the group of craniofacial malformations characterized by the premature closure of one or more cranial sutures. The disorder is clinically and genetically heterogeneous and occurs usually as an isolated trait, but can also be syndromic. In 30–60% of patients, CS is caused by known genetic factors; however, in the rest of the cases, causative molecular lesions remain unknown. In this paper, we report on a sporadic male patient affected by complex CS (metopic and unilateral lambdoid synostosis), muscular hypotonia, psychomotor retardation, and facial dysmorphism. Since a subset of CS results from submicroscopic chromosomal aberrations, we performed array comparative genomic hybridization (array CGH) in order to identify possibly causative copy-number variation. Array CGH followed by breakpoint sequencing revealed a previously unreported de novo 1.26 Mb duplication at chromosome 1q22-q23.1 that encompassed two genes involved in osteoblast differentiation: BGLAP, encoding osteocalcin (OCN), and LMNA, encoding lamin A/C. OCN is a major component of bone extracellular matrix and a marker of osteogenesis, whereas mutations in LMNA cause several genetic disorders called laminopathies, including mandibuloacral dysostosis (MAD) that manifests with low bone mass, severe bone deformities, and delayed closure of the cranial sutures. Since LMNA and BGLAP overexpression promote osteoblast differentiation and calcification, phenotype of our patient may result from misexpression of the genes. Based on our findings, we hypothesize that both LMNA and BGLAP may be implicated in the pathogenesis of CS in humans. However, further studies are needed to establish the exact pathomechanism underlying development of this defect.

Frequency of submicroscopic chromosomal aberrations in pregnancies without increased risk for structural chromosomal aberrations: systematic review and meta-analysis.

To establish, based on a systematic literature review, the frequency of pathogenic submicroscopic chromosomal aberrations in fetuses that are not at increased risk for unbalanced structural chromosomal aberrations, with the aim of determining whether high-resolution testing for submicroscopic aberrations is beneficial in a general pregnant population. EMBASE, PubMed, Web of Science and CENTRAL databases were searched systematically on 3 June 2016 for all relevant articles on the prevalence of pathogenic submicroscopic copy number variants (CNVs) in fetuses referred for prenatal invasive testing because of advanced maternal age (AMA) or parental anxiety (ANX). Relevant full-text articles were analyzed and the prevalence of submicroscopic CNVs was calculated based on the extracted data. Meta-analysis was conducted in a pooled cohort of 10 614 fetuses based on the 10 largest studies (n > 300) of a total of 19 that were relevant. Pooled estimate analysis indicated that 0.84% (95% CI, 0.55-1.30%) of fetuses that had invasive testing because of AMA/ANX carried a pathogenic clinically significant submicroscopic aberration. The onset/penetrance of submicroscopic findings was studied in 10 314 fetuses reported in eight papers that presented aberrant cases with all necessary details to allow assessment of the findings. The pooled estimates resulting from meta-analysis of the data indicated that an early-onset syndromic disorder was detected in 0.37% (95% CI, 0.27-0.52%) of cases, a susceptibility CNV was found in 0.30% (95% CI, 0.14-0.67%) and late-onset diseases were reported in 0.11% (95% CI, 0.05%-0.21%). The prevalence of early-onset syndromic disorders caused by a submicroscopic aberration was calculated to be 1:270. When the risk for submicroscopic aberrations is added to the individual risk for microscopic chromosomal aberrations, all pregnant women have a risk of higher than 1 in 180 for a relevant chromosomal aberration, and pregnant women under 36 years of age have a higher risk for submicroscopic pathogenic aberrations than for Down syndrome. This systematic review shows that a significant proportion of fetuses in a general pregnant population carry a submicroscopic pathogenic CNV. Based on these figures, all women should be informed on their individual risk for all pathogenic chromosomal aberrations and not only for common trisomies. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Microarray analysis in pregnancies with isolated unilateral kidney agenesis.

BackgroundThe objective of our study was to examine the risk for submicroscopic chromosomal aberrations among fetuses with apparently isolated solitary kidney.MethodsData acquisition was performed retrospectively by searching Israeli Ministry of Health-computerized database. All cases having chromosomal microarray analysis (CMA), referred because of an indication of isolated unilateral kidney agenesis between January 2013 and September 2016, were included. Rate of clinically significant CMA findings in these pregnancies was compared to pregnancies with normal ultrasound, based on a systematic review encompassing 9,792 cases and local data of 5,541 pregnancies undergoing CMA because of maternal request.ResultsOf the 81 pregnancies with isolated solitary kidney, 2 (2.47%) loss-of-copy number variants compatible with well-described deletion syndromes were reported (16p11.2-16p12.2 and 22q11.21 microdeletion syndromes). In addition, one variant of unknown significance was demonstrated. The relative risk for pathogenic CMA findings among pregnancies with isolated unilateral renal agenesis was not significantly different compared with the control population.ConclusionCMA analysis in pregnancies with unilateral renal agenesis might still be useful, to the same degree as it can be in the general population.

OP08.06: Is aberrant right subclavian artery in fetuses a risk factor for microscopic and submicroscopic chromosomal aberrations?

OP08.06: Is aberrant right subclavian artery in fetuses a risk factor for microscopic and submicroscopic chromosomal aberrations?

P16.05: The influence of chromosomal microarray and NIPT on the diagnostic yield in 6,811 high‐risk pregnancies without ultrasound anomalies

Prenatal diagnostics has been impacted by technological changes in the past decade, which have affected the diagnostic yield. The aim of this study was to evaluate the impact of SNP array and non-invasive prenatal testing (NIPT) on the diagnostic yield and the number of invasive tests in our centre. The frequency of pathogenic fetal unbalanced chromosome aberrations was studied in 6811 high risk pregnancies without ultrasound anomalies referred for prenatal testing in 2009-2015 due to advanced maternal age, abnormal first trimester screening results (with nuchal translucency < 3.5mm) or recurrence risk for chromosome aberration. Chromosomal SNP microarray analysis replaced karyotyping in 2012 and since 2014 a choice between NIPT and diagnostic testing with microarray was offered to women with an increased risk for common aneuploidy (as a part of a national TRIDENT study). The introduction of microarray led to an additional yield of submicroscopic pathogenic chromosome aberrations in 1.9% in fetuses without ultrasound anomalies. The introduction of NIPT led to a decrease of invasive tests, but also of the diagnostic yield. Supporting information can be found in the online version of this abstract Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

P16.04: Prevalence of submicroscopic chromosome aberrations in pregnancies without increased risk for structural chromosome aberrations: a systematic review of the literature

P16.04: Prevalence of submicroscopic chromosome aberrations in pregnancies without increased risk for structural chromosome aberrations: a systematic review of the literature

The influence of SNP-based chromosomal microarray and NIPT on the diagnostic yield in 10,000 fetuses with and without fetal ultrasound anomalies

Prenatal diagnostics has been impacted by technological changes in the past decade, which have affected the diagnostic yield. The aim of this study was to evaluate the impact of SNP array and noninvasive prenatal testing (NIPT) on the diagnostic yield and the number of invasive tests in our center. The frequency of pathogenic fetal unbalanced chromosome aberrations was studied in 10,005 cases referred for prenatal testing in 2009-2015. Chromosomal SNP microarray analysis replaced karyotyping in all invasively tested pregnancies and since 2014 a choice between NIPT and diagnostic testing with microarray was offered to women with an increased risk for common aneuploidy. The introduction of microarray led to an additional yield of submicroscopic pathogenic chromosome aberrations: 3.6% in fetuses with ultrasound anomalies and 1.9% in fetuses without ultrasound anomalies. The introduction of NIPT led to a decrease of invasive tests and of diagnostic yield. Moreover, a diagnostic delay in about 1:350 cases was observed. Since 20%-33% of pathogenic fetal chromosome aberrations are different from the common aneuploidies and triploidy, whole-genome analysis should be offered after invasive sampling. Because NIPT (as a second screening) has led to a decreased diagnostic yield, it should be accompanied by an appropriate pretest counseling.

Prenatal diagnosis of submicroscopic chromosomal aberrations in fetuses with ventricular septal defects by chromosomal microarray-based analysis.

To evaluate the usefulness of chromosomal microarray analysis in fetuses with ventricular septal defects (VSDs) with or without associated anomalies and normal karyotype. Fetuses with VSDs and normal karyotypes were investigated by using an Affymetrix CytoScan HD array. The cases were classified as isolated or nonisolated VSDs. Among the 52 VSD fetuses, 22 (42.3%) had isolated defects and 30 (57.7%) had additional other ultrasound anomalies. Twenty-six CNVs were identified in 18 fetuses (34.6%), 15 benign CNVs were detected in 11 (21.2%) fetuses, and 8 pathogenic CNVs were detected in 6 (11.5%) fetuses. After excluding 2 fetuses with 22q11.2 deletion syndrome, the rate of pathogenic CNVs was 7.7%. The proportion of variants of unknown significance was 5.8% (3/52). In five cases, additional malformations were detected after birth or abortion, and one case had a prenatal isolated VSD. The detection rate of pathogenic CNVs in nonisolated VSDs was nonsignificantly higher than that in prenatal or postnatal isolated VSDs (4.5%, 1/22 vs 16.7%, 5/30, P = 0.226; 0/21 vs 19.4%, 6/31, P = 0.07). The results demonstrated the value of chromosomal microarray analysis in the prenatal diagnosis of VSDs. The complexity of other defects enhanced the frequency of pathogenic CNVs, although the results were not significantly different. © 2016 John Wiley & Sons, Ltd.

Cytogenomic Evaluation of Children with Congenital Anomalies: Critical Implications for Diagnostic Testing and Genetic Counseling.

Identification of submicroscopic chromosomal aberrations, as a cause of structural malformations, is currently performed by MLPA (multiplex ligation-dependent probe amplification) or array CGH (array comparative genomic hybridization) techniques. The aim of this study was the evaluation of diagnostic usefulness of MLPA and array CGH in patients with congenital malformations or abnormalities (at least one major or minor birth defect, including dysmorphism) with or without intellectual disability or developmental delay and the optimization of genetic counseling in the context of the results obtained. The MLPA and array CGH were performed in 91 patients diagnosed with developmental disorders and major or minor congenital anomalies. A total of 49 MLPA tests toward common microdeletion syndromes, 42 MLPA tests for subtelomeric regions of chromosomes, two tests for common aberrations in autism, and five array CGH tests were performed. Eight (9 %) patients were diagnosed with microdeletion MLPA, four (4 %) patients with subtelomeric MLPA, one (1 %) patient with autism MLPA. Further three (3 %) individuals had rearrangements diagnosed by array CGH. Altogether, chromosomal microaberrations were found in 16 patients (17 %). All the MLPA-detected rearrangements were found to be pathogenic, but none detected with array CGH could unequivocally be interpreted as pathogenic. In patients with congenital anomalies, the application of MLPA and array CGH techniques is efficient in detecting syndromic and unique microrearrangements. Consistent pre-MLPA test phenotyping leads to better post-test genetic counseling. Incomplete penetrance and unknown inheritance of detected variants are major issues in clinical interpretation of array CGH data.