Fetal cardiac abnormalities: Genetic etiologies to be considered

The incremental yield of prenatal exome sequencing over chromosome microarray for congenital heart abnormalities: A systematic review and meta-analysis

OBJECTIVES

To determine the incremental yield of prenatal exome sequencing (PES) over standard testing in fetuses with an isolated congenital heart abnormality (CHA), CHA associated with extra-cardiac malformations (ECMs) and CHA dependent upon anatomical subclassification.

METHODS

A systematic review of the literature was performed using MEDLINE, EMBASE, Web of Science and grey literature January 2010-February 2023. Studies were selected if they included greater than 20 cases of prenatally diagnosed CHA when standard testing (QF-PCR/chromosome microarray/karyotype) was negative. Pooled incremental yield was determined. PROSPERO CRD 42022364747.

RESULTS

Overall, 21 studies, incorporating 1957 cases were included. The incremental yield of PES (causative pathogenic and likely pathogenic variants) over standard testing was 17.4% (95% CI, 13.5%-21.6%), 9.3% (95% CI, 6.6%-12.3%) and 35.9% (95% CI, 21.0%-52.3%) for all CHAs, isolated CHAs and CHAs associated with ECMs. The subgroup with the greatest yield was complex lesions/heterotaxy; 35.2% (95% CI 9.7%-65.3%). The most common syndrome was Kabuki syndrome (31/256, 12.1%) and most pathogenic variants occurred de novo and in autosomal dominant (monoallelic) disease causing genes (114/224, 50.9%).

CONCLUSION

The likelihood of a monogenic aetiology in fetuses with multi-system CHAs is high. Clinicians must consider the clinical utility of offering PES in selected isolated cardiac lesions.

Epidemiology of congenital heart defects in France from 2013 to 2022 using the PMSI-MCO (French Medical Information System Program in Medicine, Surgery, and Obstetrics) database

BACKGROUND

Congenital heart defects are common and occur in approximately 0.9% of births. In France, the registries cover approximately 20% of the population but not the entirety of France; therefore, we aimed to update the incidence data for congenital heart defects in France from 2013 to 2022 using the medico-administrative database PMSI-MCO (French Medical Information System Program in Medicine, Surgery, and Obstetrics). We aimed to compare the frequency of risk factors in a population with congenital heart defects and a reference population.

METHODS

From 2013 to 2022, we included children aged < 3 years diagnosed with congenital heart defects according to the International Classification of Diseases, 10th Revision, in the PMSI-MCO database. We compared them with a population without congenital defects on several medical data items (e.g., parity, gemellarity, and mortality rate). Bivariate and multivariate analyses compared children with congenital heart defects and children without congenital malformation.

RESULTS

We identified 83,879 children with congenital heart defects in France from 2013 to 2022 in the PMSI-MCO database and 7,739,840 children without such defects, including 7,218,952 without any congenital defects. We observed more deaths (7.49% vs. 0.68%, d = 0.59) and more twinning (8.67% vs. 1.23%, d = 0.35) among children with congenital heart defects. Multivariate analysis revealed an increased risk of congenital heart defects in male individuals (OR [odds ratio] 1.056, 95% CI [confidence interval] [1.039-1.076]) and cases of medically assisted reproduction (OR 1.115, 95% CI [1.045-1.189]) and a reduced risk in the case of multiparity (OR 0.921, 95% CI [0.905-0.938]).

CONCLUSIONS

According to the PMSI-MCO database, the incidence of congenital heart defects in France from 2013 to 2022 is 1% of births. Congenital heart defects are more frequent in cases of prematurity, twinning, primiparity, male sex, and maternal age > 40 years.

Preliminary study of noninvasive prenatal screening for 22q11.2 deletion/duplication syndrome using multiplex dPCR assay

OBJECTIVE

This study aimed to establish a cell-free fetal DNA (cffDNA) assay using multiplex digital PCR (dPCR) for identifying fetuses at increased risk of 22q11.2 deletion/duplication syndrome.

METHODS

Six detection sites and their corresponding probes were designed for the 22q11.2 recurrent region. A dPCR assay for the noninvasive screening of 22q11.2 deletion/duplication syndrome was established. A total of 130 plasma samples from pregnant women (including 15 samples with fetal 22q11.2 deletion/duplication syndrome) were blindly tested for evaluating the sensitivity and specificity of the established assay.

RESULTS

DNA with different sizes of 22q11.2 deletion/duplication was detected via dPCR, indicating that the designed probes and detection sites were reasonable and effective. In the retrospective clinical samples, 11 out of 15 samples of pregnant women with 22q11.2 deletion/duplication were detected during the cffDNA assay, and accurate regional localization was achieved. Among the 115 normal samples, 111 were confirmed to be normal. Receiver operating characteristic curves were used for assessing the cut-off values and AUC for these samples. The sensitivity, specificity, and positive as well as negative predictive values were 73.3%, 96.5%, 73.3%, and 96.5%, respectively.

CONCLUSION

The cffDNA assay based on dPCR technology for the noninvasive detection of 22q11.2 recurrent copy number variants in fetuses detected most affected cases, including smaller but relatively common nested deletions, with a low false-positive rate. It is a potential, efficient and simple method for the noninvasive screening of 22q11.2 deletion/duplication syndrome.

Genetic abnormalities in fetal congenital heart disease with aberrant right subclavian artery

Fetal aberrant right subclavian artery (ARSA) is a relatively common sonographic finding. Congenital heart disease (CHD) is the most common structural abnormality in patients with ARSA. We aimed to assess the prevalence of genetic abnormalities, particularly sequence variants, in fetuses with CHD and ARSA. By clinical phenotyping and genomic sequencing, we retrospectively reviewed all fetuses with a prenatal diagnosis of CHD combined with ARSA at a single center. As a result, we identified 30 fetuses with ARSA combined with CHD, with conotruncal anomalies being the most common (n = 12, 40%), followed by left ventricular outflow tract obstruction (n = 6, 20%) and atrioventricular septal defects (n = 6, 20%). Overall, 18 (60%) cases had a genetic diagnosis. Copy number variation sequencing analysis identified six (20%) fetuses with aneuploidy and seven (23%) with pathogenic copy-number variants. Whole-exome sequencing (WES) analysis of the remaining 17 cases revealed diagnostic genetic variants in five (29%) cases, indicating that the diagnostic yield of WES for the entire cohort was 17% (5/30). Our findings reveal the high burden of genetic abnormalities in fetal CHD with ARSA. Single-gene disorders contribute substantially to the genetic etiology of fetal CHD with ARSA.

Outcome after Prenatal Diagnosis of Trisomy 13, 18, and 21 in Fetuses with Congenital Heart Disease

Fetal congenital heart disease (CHD) is often associated with chromosomal abnormalities. Our primary aim was to assess stillbirth and neonatal mortality rates for pregnancies complicated by trisomies 13, 18, and 21 in the presence of CHD, from a single tertiary referral center during 2000-2020 in a retrospective cohort study. The secondary aims were to investigate maternal morbidity in these pregnancies, and to study the gestational or neonatal age when mortality occurred. Inclusion criteria were the prenatal diagnosis of at least one structural CHD, together with prenatally diagnosed fetal trisomy 13, 18, or 21. One-hundred and sixty patients with fetal trisomy 13 (14.4%), fetal trisomy 18 (28.8%), and fetal trisomy 21 (56.9%) were evaluated. In total, 98 (61.3%) families opted for the termination of pregnancy (TOP). Of the remaining 62 (38.8%) pregnancies, 16 (25.8%) resulted in intrauterine fetal death/death during delivery. Ten out of twenty-one (47.6%) infants with trisomy 13 or 18 were born alive. The livebirth rate was 87.8% (36/41) for infants with trisomy 21. Early neonatal death was observed in nine (19.6%) infants. Thirty-one (86.1%) infants with trisomy 21 survived the first year of life. These data may be helpful for counseling affected parents when the decision to terminate or continue the pregnancy should be considered.

Exploring the diagnostic utility of genome sequencing for fetal congenital heart defects

OBJECTIVE

The diagnostic yield for congenital heart defects (CHD) with routine genetic testing is around 10-20% when considering the pathogenic CNVs or aneuploidies as positive findings. This is a pilot study to investigate the utility of genome sequencing (GS) for prenatal diagnosis of CHD.

METHODS

Genome sequencing (GS, 30X) was performed on 13 trios with CHD for which karyotyping and/or chromosomal microarray results were non-diagnostic.

RESULTS

Trio GS provided a diagnosis for 4/13 (30.8%) fetuses with complex CHDs and other structural anomalies. Findings included pathogenic or likely pathogenic variants in DNAH5, COL4A1, PTPN11, and KRAS. Of nine cases without a possibly genetic etiology by GS, we had follow-up on eight. For five of them (60%), the parents chose to keep the pregnancy. A balanced translocation [46,XX,t(14;22)(q32.33;q13.31)mat] was detected in a trio with biallelic DNAH5 mutations, which together explained the recurrent fetal situs inversus and dextrocardia that was presumably due to de novo Phelan-McDermid syndrome. A secondary finding of a BRCA2 variant and carrier status of HBB, USH2A, HBA1/HBA2 were detected in the trio.

CONCLUSIONS

GS expands the diagnostic scope of mutation types over conventional testing, revealing the genetic etiology for fetal heart anomalies. Patients without a known genetic abnormality indicated by GS likely opted to keep pregnancy especially if the heart issue could be repaired. We provide evidence to support the application of GS for fetuses with CHD. This article is protected by copyright. All rights reserved.

Genetic counseling for congenital heart disease - Practice resource of the national society of genetic counselors

Congenital heart disease (CHD) is an indication which spans multiple specialties across various genetic counseling practices. This practice resource aims to provide guidance on key considerations when approaching counseling for this particular indication while recognizing the rapidly changing landscape of knowledge within this domain. This resource was developed with consensus from a diverse group of certified genetic counselors utilizing literature relevant for CHD genetic counseling practice and is aimed at supporting genetic counselors who encounter this indication in their practice both pre- and postnatally.

The Diagnostic Yield of Prenatal Genetic Technologies in Congenital Heart Disease: A Prospective Cohort Study

INTRODUCTION

The objective was to evaluate: (i) the proportion of prenatally diagnosed congenital heart disease (CHD) associated with an abnormal quantitative fluorescence-PCR (QF-PCR), chromosome microarray (CMA), and exome sequencing (ES) result; and (ii) the diagnostic yield of these technologies based on CHD category and presence of extra-cardiac anomalies (ECAs).

METHODS

This prospective cohort study was set across 12 UK foetal medicine centres. All cases underwent QF-PCR, CMA, and ES, and the diagnostic yield in n = 147 cases of prenatally diagnosed CHD was assessed.

RESULTS

In 34.7% (n = 51/147), a genetic diagnosis was obtained. Using a stepwise testing strategy, the diagnostic yield for QF-PCR, CMA, and ES was 15.6% (n = 23/147), 13.7% (n = 17/124), and 10.2% (n = 11/107), respectively. Abnormal QF-PCR/shunt (septal) defects 31.4% (n = 11/35), p = 0.046, and abnormal CMA/conotruncal anomalies 22.7% (n = 10/44), p = 0.04, had significant associations. Monogenic variants were commonest in complex CHD 36.4% (n = 4/11). Multisystem CHD had a greater diagnostic yield overall compared to isolated OR 2.41 (95% CI, 1.1-5.1), particularly in association with brain and gastrointestinal tract anomalies. The proportion of variants of uncertain significance was 4.7% (n = 5/107) with ES, with none in the CMA group.

CONCLUSION

In the era of prenatal ES, there remains an important role for QF-PCR and CMA. Identification of monogenic pathologic variants further allows delineation of prognosis in CHD.

COngenital heart disease and the Diagnostic yield with Exome sequencing (CODE) study: prospective cohort study and systematic review

OBJECTIVE

To determine the incremental yield of antenatal exome sequencing (ES) over chromosomal microarray analysis (CMA) or conventional karyotyping in prenatally diagnosed congenital heart disease (CHD).

METHODS

A prospective cohort study of 197 trios undergoing ES following CMA or karyotyping owing to CHD identified prenatally and a systematic review of the literature were performed. MEDLINE, EMBASE, CINAHL and ClinicalTrials.gov (January 2000 to October 2019) databases were searched electronically for studies reporting on the diagnostic yield of ES in prenatally diagnosed CHD. Selected studies included those with more than three cases, with initiation of testing based upon prenatal phenotype only and that included cases in which CMA or karyotyping was negative. The incremental diagnostic yield of ES was assessed in: (1) all cases of CHD; (2) isolated CHD; (3) CHD associated with extracardiac anomaly (ECA); and (4) CHD according to phenotypic subgroup.

RESULTS

In our cohort, ES had an additional diagnostic yield in all CHD, isolated CHD and CHD associated with ECA of 12.7% (25/197), 11.5% (14/122) and 14.7% (11/75), respectively (P = 0.81). The corresponding pooled incremental yields from 18 studies (encompassing 636 CHD cases) included in the systematic review were 21% (95% CI, 15-27%), 11% (95% CI, 7-15%) and 37% (95% CI, 18-56%), respectively. The results did not differ significantly when subanalysis was limited to studies including more than 20 cases, except for CHD associated with ECA, in which the incremental yield was greater (49% (95% CI, 17-80%)). In cases of CHD associated with ECA in the primary analysis, the most common extracardiac anomalies associated with a pathogenic variant were those affecting the genitourinary system (23/52 (44.2%)). The greatest incremental yield was in cardiac shunt lesions (41% (95% CI, 19-63%)), followed by right-sided lesions (26% (95% CI, 9-43%)). In the majority (68/96 (70.8%)) of instances, pathogenic variants occurred de novo and in autosomal dominant (monoallelic) disease genes. The most common (19/96 (19.8%)) monogenic syndrome identified was Kabuki syndrome.

CONCLUSIONS

There is an apparent incremental yield of prenatal ES in CHD. While the greatest yield is in CHD associated with ECA, consideration could also be given to performing ES in the presence of an isolated cardiac abnormality. A policy of routine application of ES would require the adoption of robust bioinformatic, clinical and ethical pathways. Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd.

Intrauterine phenotype features of fetuses with Williams-Beuren syndrome and literature review

Williams-Beuren syndrome (WBS) is a well-defined multisystem chromosomal disorder that is caused by a chromosome 7q11.23 region heterozygous deletion. We explored prenatal diagnosis of WBS by ultrasound as well as multiple genetic methods to characterize the structural variants of WBS prenatally. Expanded noninvasive prenatal testing (NIPT-plus) was elected as a regular prenatal advanced screen for risk assessments of fetal chromosomal aneuploidy and genome-wide microdeletion/microduplication syndromes at the first trimester. At the second and three trimester, seven prenatal cases of WBS were evaluated for the indication of the invasive testing, the ultrasound features, cytogenetic, single-nucleotide polymorphism array (SNP array), and fluorescent quantitative PCR (QF-PCR) results. The NIPT-plus results for seven fetuses were low risk. All cryptic aberrations were detected by the SNP array as karyotyping analyses were negative. Subsequently, QF-PCR further confirmed the seven deletions. Combining our cases with 10 prenatal cases from the literature, the most common sonographic features were intrauterine growth retardation (82.35%, 14/17) and congenital cardiovascular abnormalities (58.82%, 10/17). The manifestations of cardiovascular defects mainly involve supravalvar aortic stenosis (40%, 4/10), ventricular septal defect (30%, 3/10), aortic coarctation (20%, 2/10), and peripheral pulmonary artery stenosis (20%, 2/10). To the best of our knowledge, this is the first largest prenatal study of WBS cases with detailed molecular analysis. Aortic coarctation combined with persistent left superior vena cava and right aortic arch cardiovascular defects were first reported in prenatal WBS cases by our study.