Rationale for the Cytogenomics of Cardiovascular Malformations Consortium: A Phenotype Intensive Registry Based Approach

Identification of Long Noncoding RNA Candidate Disease Genes Associated With Clinically Reported Copy Number Variants in Congenital Heart Disease

BACKGROUND

Copy number variants (CNVs) contribute to 3% to 10% of isolated congenital heart disease (CHD) cases, yet their pathogenic roles remain unclear. Diagnostic efforts have focused on protein-coding genes, largely overlooking long noncoding RNAs (lncRNAs), which play key roles in development and disease.

METHODS AND RESULTS

We systematically analyzed lncRNAs overlapping clinically validated CNVs in 743 patients with CHD from the Cytogenomics of Cardiovascular Malformations Consortium. We identified heart-expressed lncRNAs, constructed a gene regulatory network using weighted gene coexpression network analysis, and identified gene modules associated with heart development. Functional enrichment and network analyses were used to identify lncRNAs that may be involved in heart development and potentially contribute to CHD. The code is stably archived at https://doi.org/10.5281/zenodo.13799779. We identified 18 lncRNA candidate genes within modules significantly correlated with heart tissue, highlighting their potential involvement in CHD pathogenesis. Notably, lncRNAs such as lnc-STK32C-3, lnc-TBX20-1, and CRMA demonstrated strong associations with known CHD genes. Strikingly, although only 7.6% of known CHD genes were affected by a CNV, 68.8% of the CNVs contained a lncRNA expressed in the heart.

CONCLUSIONS

Using weighted gene coexpression network analysis, we identified CNV-associated lncRNAs with potential relevance to CHD, underscoring the complexities of noncoding regions in disease pathogenesis. These findings suggest that lncRNAs may play a greater role in CHD than previously recognized, highlighting the need for broader genomic analyses that extend beyond protein-coding genes. This study provides a foundation for further exploration of lncRNAs in CHD, with potential implications for improved genetic characterization and diagnosis.

Performance of Dysmorphology-Based Screening for Genetic Disorders in Pediatric Congenital Heart Disease Supports Wider Genetic Testing

BACKGROUND

Dysmorphology evaluation is important for congenital heart disease (CHD) assessment, but there are no prior investigations quantifying the screening performance compared to standardized genetics evaluations. We investigated this through systematic dysmorphology assessment in CHD patients with standardized genetic testing in primarily pediatric patients with CHD.

METHODS

Dysmorphology evaluations preceding genetic testing results allowed us to test for associations between dysmorphic status and genetic diagnoses while adjusting for extracardiac anomalies (ECAs). We use a test-negative case-control design on a pediatric inpatient CHD cohort for our study.

RESULTS

Of 568 patients, nearly 96% of patients completed genetic testing, primarily chromosome microarray (CMA) ± exome sequencing-based genetic testing (493/568, 86.8%). Overall, 115 patients (20.2%) were found to have genetic diagnoses, and dysmorphic patients had doubled risk of genetic diagnoses, after ECA adjustment (OR = 2.10, p = 0.0030). We found that 7.9% (14/178) of ECA-/nondysmorphic patients had genetic diagnoses, which increased to 13.5% (26/192) in the ECA-/dysmorphic patients. Nearly 43% of ECA+/dysmorphic patients had genetic diagnoses (63/147). The positive predictive value of dysmorphic status was only 26.3%, and the negative predictive value of nondysmorphic status was 88.7%.

CONCLUSIONS

Dysmorphology-based prediction of genetic disorders is limited because of diagnoses found in apparently isolated CHD. Our findings represent one of the only assessments of phenotype-based screening for genetic disorders in CHD and should inform clinical genetics evaluation practices for pediatric CHD.

Case Report: An association of left ventricular outflow tract obstruction with 5p deletions

Introduction

5p deletion syndrome, also called Cri-du-chat syndrome 5p is a rare genetic syndrome with reports up to 36% of patients are associated with congenital heart defects. We investigated the association between left outflow tract obstruction and Cri-du-chat syndrome.

Methods

A retrospective review of the abnormal microarray cases with congenital heart defects in Children's Hospital of Pittsburgh and the Cytogenomics of Cardiovascular Malformations Consortium.

Results

A retrospective review at nine pediatric centers identified 4 patients with 5p deletions and left outflow tract obstruction (LVOTO). Three of these patients had additional copy number variants. We present data suggesting an association of LVOTO with 5p deletion with high mortality in the presence of additional copy number variants.

Conclusion

A rare combination of 5p deletion and left ventricular outflow obstruction was observed in the registry of copy number variants and congenital heart defects.

Clinical exome sequencing efficacy and phenotypic expansions involving anomalous pulmonary venous return

Anomalous pulmonary venous return (APVR) frequently occurs with other congenital heart defects (CHDs) or extra-cardiac anomalies. While some genetic causes have been identified, the optimal approach to genetic testing in individuals with APVR remains uncertain, and the etiology of most cases of APVR is unclear. Here, we analyzed molecular data from 49 individuals to determine the diagnostic yield of clinical exome sequencing (ES) for non-isolated APVR. A definitive or probable diagnosis was made for 8 of those individuals yielding a diagnostic efficacy rate of 16.3%. We then analyzed molecular data from 62 individuals with APVR accrued from three databases to identify novel APVR genes. Based on data from this analysis, published case reports, mouse models, and/or similarity to known APVR genes as revealed by a machine learning algorithm, we identified 3 genes-EFTUD2, NAA15, and NKX2-1-for which there is sufficient evidence to support phenotypic expansion to include APVR. We also provide evidence that 3 recurrent copy number variants contribute to the development of APVR: proximal 1q21.1 microdeletions involving RBM8A and PDZK1, recurrent BP1-BP2 15q11.2 deletions, and central 22q11.2 deletions involving CRKL. Our results suggest that ES and chromosomal microarray analysis (or genome sequencing) should be considered for individuals with non-isolated APVR for whom a genetic etiology has not been identified, and that genetic testing to identify an independent genetic etiology of APVR is not warranted in individuals with EFTUD2-, NAA15-, and NKX2-1-related disorders.

Double outlet right ventricle

This review article addresses the history, morphology, anatomy, medical management, and different surgical options for patients with double outlet right ventricle.

A Multicenter Analysis of Abnormal Chromosomal Microarray Findings in Congenital Heart Disease

Background Chromosomal microarray analysis (CMA) provides an opportunity to understand genetic causes of congenital heart disease (CHD). The methods for describing cardiac phenotypes in patients with CMA abnormalities have been inconsistent, which may complicate clinical interpretation of abnormal testing results and hinder a more complete understanding of genotype-phenotype relationships. Methods and Results Patients with CHD and abnormal clinical CMA were accrued from 9 pediatric cardiac centers. Highly detailed cardiac phenotypes were systematically classified and analyzed for their association with CMA abnormality. Hierarchical classification of each patient into 1 CHD category facilitated broad analyses. Inclusive classification allowing multiple CHD types per patient provided sensitive descriptions. In 1363 registry patients, 28% had genomic disorders with well-recognized CHD association, 67% had clinically reported copy number variants (CNVs) with rare or no prior CHD association, and 5% had regions of homozygosity without CNV. Hierarchical classification identified expected CHD categories in genomic disorders, as well as uncharacteristic CHDs. Inclusive phenotyping provided sensitive descriptions of patients with multiple CHD types, which occurred commonly. Among CNVs with rare or no prior CHD association, submicroscopic CNVs were enriched for more complex types of CHD compared with large CNVs. The submicroscopic CNVs that contained a curated CHD gene were enriched for left ventricular obstruction or septal defects, whereas CNVs containing a single gene were enriched for conotruncal defects. Neuronal-related pathways were over-represented in single-gene CNVs, including top candidate causative genes NRXN3, ADCY2, and HCN1. Conclusions Intensive cardiac phenotyping in multisite registry data identifies genotype-phenotype associations in CHD patients with abnormal CMA.

A multicenter cross-sectional study in infants with congenital heart defects demonstrates high diagnostic yield of genetic testing but variable evaluation practices

Purpose

For patients with congenital heart disease (CHD), the most common birth defect, genetic evaluation is not universally accepted, and current practices are anecdotal. Here, we analyzed genetic evaluation practices across centers, determined diagnostic yield of testing, and identified phenotypic features associated with abnormal results.

Methods

This is a multicenter cross-sectional study of 5 large children's hospitals, including 2899 children ≤14 months undergoing surgical repair for CHD from 2013 to 2016, followed by multivariate logistics regression analysis.

Results

Genetic testing occurred in 1607 of 2899 patients (55%). Testing rates differed highly between institutions (42%-78%, P < .001). Choice of testing modality also differed across institutions (ie, chromosomal microarray, 26%-67%, P < .001). Genetic testing was abnormal in 702 of 1607 patients (44%), and no major phenotypic feature drove diagnostic yield. Only 849 patients were seen by geneticists (29%), ranging across centers (15%-52%, P < .001). Geneticist consultation associated with increased genetic testing yield (odds ratio: 5.7, 95% CI 4.33-7.58, P < .001).

Conclusion

Genetics evaluation in CHD is diagnostically important but underused and highly variable, with high diagnostic rates across patient types, including in infants with presumed isolated CHD. These findings support recommendations for comprehensive testing and standardization of care.

A Comprehensive Clinical Genetics Approach to Critical Congenital Heart Disease in Infancy

OBJECTIVE

To investigate the frequency of genetic diagnoses among infants with critical congenital heart disease (CHD) using a comprehensive cardiovascular genetics approach and to identify genotype-phenotype correlations.

STUDY DESIGN

A retrospective chart review of patients evaluated by cardiovascular genetics in a pediatric cardiac intensive care unit from 2010 to 2015 was performed. Infants with CHD who were <1 month of age were included. CHD was classified using structured phenotype definitions. Cardiac and noncardiac phenotypes were tested for associations with abnormal genetic testing using χ¹ and Fisher exact tests.

RESULTS

Genetic evaluation was completed in 293 infants with CHD, of whom 213 had isolated congenital heart disease (iCHD) and 80 had multiple congenital anomalies. Overall, the yield of abnormal genetic testing was 26%. The multiple congenital anomalies cohort had a greater yield of genetic testing (39%) than the iCHD cohort (20%) (OR 2.7). Using a non-hierarchical CHD classification and excluding 22q11.2 deletion and common aneuploidies, right ventricular obstructive defects were associated with abnormal genetic testing (P = .0005). Extracardiac features associated with abnormal genetic testing included ear, nose, and throat (P = .003) and brain (P = .0001) abnormalities. A diagnosis of small for gestational age or intrauterine growth retardation also was associated with abnormal genetic testing (P = .0061), as was presence of dysmorphic features (P = .0033, OR 3.5). Infants without dysmorphia with iCHD or multiple congenital anomalies had similar frequencies of abnormal genetic testing.

CONCLUSIONS

The present study provides evidence to support a comprehensive cardiovascular genetics approach in evaluating infants with critical CHD while also identifying important genotype-phenotype considerations.

Variants of significance: medical genetics and surgical outcomes in congenital heart disease

PURPOSE OF REVIEW

This article reviews the current understanding and limitations in knowledge of the effect genetics and genetic diagnoses have on perioperative and postoperative surgical outcomes in patients with congenital heart disease (CHD).

RECENT FINDINGS

Presence of a known genetic diagnosis seems to effect multiple significant outcome metrics in CHD surgery including length of stay, need for extracorporeal membrane oxygenation, mortality, bleeding, and heart failure. Data regarding the effects of genetics in CHD is complicated by lack of standard genetic assessment resulting in inaccurate risk stratification of patients when analyzing data. Only 30% of variation in CHD surgical outcomes are explained by currently measured variables, with 2.5% being attributed to diagnosed genetic disorders, it is thought a significant amount of the remaining outcome variation is because of unmeasured genetic factors.

SUMMARY

Genetic diagnoses clearly have a significant effect on surgical outcomes in patients with CHD. Our current understanding is limited by lack of consistent genetic evaluation and assessment as well as evolving knowledge and discovery regarding the genetics of CHD. Standardizing genetic assessment of patients with CHD will allow for the best risk stratification and ultimate understanding of these effects.

Genetic evaluation of patients with congenital heart disease

PURPOSE OF REVIEW

The aim of this study is to review genetics of congenital heart disease (CHD) with a focus on clinical applications, genetic testing and clinical challenges.

RECENT FINDINGS

With improved clinical care, there is a rapidly expanding population of adults, especially women, with CHD who have not undergone contemporary genetic assessment and do not understand their risk for having a child with CHD. Many patients have never undergone assessment or had genetic testing. A major barrier is medical geneticist availability, resulting in this burden of care shifting to providers outside of genetics. Even with current understanding, the cause for the majority of cases of CHD is still not known. There are significant gaps in knowledge in the realms of more complex causes such as noncoding variants, multigenic contribution and small structural chromosomal anomalies.

SUMMARY

Standard assessment of patients with CHD, including adult survivors, is indicated. The best first-line genetic assessment for most patients with CHD is a chromosomal microarray, and this will soon evolve to be genomic sequencing with copy number variant analysis. Due to lack of medical geneticists, creative solutions to maximize the number of patients with CHD who undergo assessment with standard protocols and plans for support with result interpretation need to be explored.

Heart Failure in Pediatric Patients With Congenital Heart Disease

Heart failure (HF) is a complex clinical syndrome resulting from diverse primary and secondary causes and shared pathways of disease progression, correlating with substantial mortality, morbidity, and cost. HF in children is most commonly attributable to coexistent congenital heart disease, with different risks depending on the specific type of malformation. Current management and therapy for HF in children are extrapolated from treatment approaches in adults. This review discusses the causes, epidemiology, and manifestations of HF in children with congenital heart disease and presents the clinical, genetic, and molecular characteristics that are similar or distinct from adult HF. The objective of this review is to provide a framework for understanding rapidly increasing genetic and molecular information in the challenging context of detailed phenotyping. We review clinical and translational research studies of HF in congenital heart disease including at the genome, transcriptome, and epigenetic levels. Unresolved issues and directions for future study are presented.