Factors influencing participation in a population-based biorepository for childhood heart disease

Genome-wide enhancer-associated tandem repeats are expanded in cardiomyopathy

BACKGROUND

Cardiomyopathy is a clinically and genetically heterogeneous heart condition that can lead to heart failure and sudden cardiac death in childhood. While it has a strong genetic basis, the genetic aetiology for over 50% of cardiomyopathy cases remains unknown.

METHODS

In this study, we analyse the characteristics of tandem repeats from genome sequence data of unrelated individuals diagnosed with cardiomyopathy from Canada and the United Kingdom (n = 1216) and compare them to those found in the general population. We perform burden analysis to identify genomic and epigenomic features that are impacted by rare tandem repeat expansions (TREs), and enrichment analysis to identify functional pathways that are involved in the TRE-associated genes in cardiomyopathy. We use Oxford Nanopore targeted long-read sequencing to validate repeat size and methylation status of one of the most recurrent TREs. We also compare the TRE-associated genes to those that are dysregulated in the heart tissues of individuals with cardiomyopathy.

FINDINGS

We demonstrate that tandem repeats that are rarely expanded in the general population are predominantly expanded in cardiomyopathy. We find that rare TREs are disproportionately present in constrained genes near transcriptional start sites, have high GC content, and frequently overlap active enhancer H3K27ac marks, where expansion-related DNA methylation may reduce gene expression. We demonstrate the gene silencing effect of expanded CGG tandem repeats in DIP2B through promoter hypermethylation. We show that the enhancer-associated loci are found in genes that are highly expressed in human cardiomyocytes and are differentially expressed in the left ventricle of the heart in individuals with cardiomyopathy.

INTERPRETATION

Our findings highlight the underrecognized contribution of rare tandem repeat expansions to the risk of cardiomyopathy and suggest that rare TREs contribute to ∼4% of cardiomyopathy risk.

FUNDING

Government of Ontario (RKCY), The Canadian Institutes of Health Research PJT 175329 (RKCY), The Azrieli Foundation (RKCY), SickKids Catalyst Scholar in Genetics (RKCY), The University of Toronto McLaughlin Centre (RKCY, SM), Ted Rogers Centre for Heart Research (SM), Data Sciences Institute at the University of Toronto (SM), The Canadian Institutes of Health Research PJT 175034 (SM), The Canadian Institutes of Health Research ENP 161429 under the frame of ERA PerMed (SM, RL), Heart and Stroke Foundation of Ontario & Robert M Freedom Chair in Cardiovascular Science (SM), Bitove Family Professorship of Adult Congenital Heart Disease (EO), Canada Foundation for Innovation (SWS, JR), Canada Research Chair (PS), Genome Canada (PS, JR), The Canadian Institutes of Health Research (PS).

Age and Sex Differences in the Genetics of Cardiomyopathy

Cardiomyopathy has variable penetrance. We analyzed age and sex-related genetic differences in 1,397 cardiomyopathy patients (Ontario, UK) with whole genome sequencing. Pediatric cases (n = 471) harbored more deleterious protein-coding variants in Tier 1 cardiomyopathy genes compared to adults (n = 926) (34.6% vs 25.9% respectively, p = 0.0015), with variant enrichment in constrained coding regions. Pediatric patients had a higher burden of sarcomere and lower burden of channelopathy gene variants compared to adults. Specifically, pediatric patients had more MYH7 and MYL3 variants in hypertrophic cardiomyopathy, and fewer TTN truncating variants in dilated cardiomyopathy. MYH7 variants clustered in the myosin head and neck domains in children. OBSCN was a top mutated gene in adults, enriched for protein-truncating variants. In dilated cardiomyopathy, female patients had a higher burden of z-disc gene variants compared to males. Genetic differences may explain age and sex-related variability in cardiomyopathy penetrance. Genotype-guided predictions of age of onset can inform pre-test genetic counseling. Pediatric cardiomyopathy patients were more likely to be genotype-positive than adults with a higher burden of variants in MYH7, MYL3, TNNT2, VCL. Adults had a higher burden of OBSCN and TTN variants. Females with dilated cardiomyopathy (DCM) had a higher burden of z-disc gene variants compared to males.

Rare variants in CAPN2 increase risk for isolated hypoplastic left heart syndrome

Hypoplastic left heart syndrome (HLHS) is a severe congenital heart defect (CHD) characterized by hypoplasia of the left ventricle and aorta along with stenosis or atresia of the aortic and mitral valves. HLHS represents only ∼4%-8% of all CHDs but accounts for ∼25% of deaths. HLHS is an isolated defect (i.e., iHLHS) in 70% of families, the vast majority of which are simplex. Despite intense investigation, the genetic basis of iHLHS remains largely unknown. We performed exome sequencing on 331 families with iHLHS aggregated from four independent cohorts. A Mendelian-model-based analysis demonstrated that iHLHS was not due to single, large-effect alleles in genes previously reported to underlie iHLHS or CHD in >90% of families in this cohort. Gene-based association testing identified increased risk for iHLHS associated with variation in CAPN2 (p = 1.8 × 10-5), encoding a protein involved in functional adhesion. Functional validation studies in a vertebrate animal model (Xenopus laevis) confirmed CAPN2 is essential for cardiac ventricle morphogenesis and that in vivo loss of calpain function causes hypoplastic ventricle phenotypes and suggest that human CAPN2707C>T and CAPN21112C>T variants, each found in multiple individuals with iHLHS, are hypomorphic alleles. Collectively, our findings show that iHLHS is typically not a Mendelian condition, demonstrate that CAPN2 variants increase risk of iHLHS, and identify a novel pathway involved in HLHS pathogenesis.

Pediatric biobanks to enhance clinical and translational research for children

Including children in biomedical research is an argument for continual reflection and practice refinement from an ethical and legal standpoint. Indeed, as children reach adulthood, a reconsent method should be used, and data connected with samples should ideally be updated based on the children's growth and long-term results. Furthermore, because most pediatric disorders are uncommon, children's research initiatives should conform to standard operating procedures (SOPs) set by worldwide scientific organizations for successfully sharing data and samples. Here, we examine how pediatric biobanks can help address some challenges to improve biomedical research for children. Indeed, modern biobanks are evolving as complex research platforms with specialized employees, dedicated spaces, information technologies services (ITS), and ethical and legal expertise. In the case of research for children, biobanks can collaborate with scientific networks (i.e., BBMRI-ERIC) and provide the collection, storage, and distribution of biosamples in agreement with international standard procedures (ISO-20387). Close collaboration among biobanks provides shared avenues for maximizing scarce biological samples, which is required to promote the translation of scientific breakthroughs for developing clinical care and health policies tailored to the pediatric population. Moreover, biobanks, through their science communication and dissemination activities (i.e., European Biobank Week), may be helpful for children to understand what it means to be engaged in a research study, allowing them to see it as a pleasant, useful, and empowering experience. Additionally, biobanks can notify each participant about which projects have been accomplished (i.e., through their websites, social media networks, etc.); they can facilitate future reconsent procedures and update sample-associated data based on the children's growth. Finally, because of the increasing interest from public and commercial organizations in research efforts that include the sharing and reuse of health data, pediatric biobanks have a crucial role in this context. Consequently, they could benefit from funding opportunities for sustaining research activities even regarding rare pediatric disorders.  Conclusion: Pediatric biobanks are helpful for providing biological material for research purposes, addressing ethical and legal issues (i.e. data protection, consent, etc.), and providing control samples from healthy children of various ages and from different geographical regions and ethnicities. Therefore, it is vital to encourage and maintain children's engagement in medical research programs and biobanking activities, especially as children become adults, and reconsent procedures must be applied. What is Known: • Biobanks are critical research infrastructures for medical research, especially in the era of "omic" science. However, in light of their fragility and rights children's participation in biobanking and medical research programs is a complex argument of continuous debate in scientific literature. What is New: • We propose a review of the literature on pediatric biobanks with a particular focus on oncological biobanks. The main current limitations and challenges for pediatric biobanks are presented and possible solutions are discussed.

Parental Views of Facilitators and Barriers to Research Participation: Systematic Review

BACKGROUND AND OBJECTIVES

Low enrollment within pediatric research increases the cost of research, decreases generalizability, and threatens to exacerbate existing health disparities. To assess barriers and facilitators to pediatric research participation and evaluate differences by enrollment status.

METHODS

Data Sources include PubMed, Embase, PsycInfo, Cumulative Index to Nursing and Allied Health Literature, and Web of Science. Study selection include peer reviewed articles that contained information related to facilitators and barriers to the parental decision whether to enroll their child in research and included the views of parents who declined. We extracted barriers and facilitators to research, enrollment status, and study characteristics, including study design, quality, and patient population.

RESULTS

Seventy articles were included for analysis. Facilitators of participation included: benefits, trust, support of research, informational and consent related, and relational issues. Common facilitators within those categories included health benefit to child (N = 39), altruism (N = 30), and the importance of research (N = 26). Barriers to participation included: study-related concerns, burdens of participation, lack of trust, general research concerns, informational and consent related, and relational issues. Common barriers within those categories included risks to child (N = 46), burdens of participation (N = 35), and the stress of the decision (N = 29). We had a limited ability to directly compare by enrollment status and no ability to analyze interactions between facilitators and barriers. We only included studies written in English.

CONCLUSIONS

This review identified key facilitators and barriers to research participation in pediatrics. The findings from this review may guide researchers aiming to create interventions to improve the parental experience of recruitment for pediatric studies and to optimize enrollment rates.

Whole genome sequencing delineates regulatory, copy number, and cryptic splice variants in early onset cardiomyopathy

Cardiomyopathy (CMP) is a heritable disorder. Over 50% of cases are gene-elusive on clinical gene panel testing. The contribution of variants in non-coding DNA elements that result in cryptic splicing and regulate gene expression has not been explored. We analyzed whole-genome sequencing (WGS) data in a discovery cohort of 209 pediatric CMP patients and 1953 independent replication genomes and exomes. We searched for protein-coding variants, and non-coding variants predicted to affect the function or expression of genes. Thirty-nine percent of cases harbored pathogenic coding variants in known CMP genes, and 5% harbored high-risk loss-of-function (LoF) variants in additional candidate CMP genes. Fifteen percent harbored high-risk regulatory variants in promoters and enhancers of CMP genes (odds ratio 2.25, p = 6.70 × 10-7 versus controls). Genes involved in α-dystroglycan glycosylation (FKTN, DTNA) and desmosomal signaling (DSC2, DSG2) were most highly enriched for regulatory variants (odds ratio 6.7-58.1). Functional effects were confirmed in patient myocardium and reporter assays in human cardiomyocytes, and in zebrafish CRISPR knockouts. We provide strong evidence for the genomic contribution of functionally active variants in new genes and in regulatory elements of known CMP genes to early onset CMP.

Pediatric biorepository participation during the COVID-19 pandemic: predictors of enrollment and biospecimen donation

Background

Patient-level predictors of enrollment in pediatric biorepositories are poorly described. Especially in pandemic settings, understanding who is likely to enroll in a biorepository is critical to interpreting analyses conducted on biospecimens. We describe predictors of pediatric COVID-19 biorepository enrollment and biospecimen donation to identify gaps in COVID-19 research on pediatric biospecimens.

Methods

We compared data from enrollees and non-enrollees aged 0–25 years with suspected or confirmed COVID-19 infection who were approached for enrollment in the Massachusetts General Hospital pediatric COVID-19 biorepository between April 12, 2020, and May 28, 2020, from community or academic outpatient or inpatient settings. Demographic and clinical data at presentation to care were from automatic and manual chart extractions. Predictors of enrollment and biospecimen donation were assessed with Poisson regression models.

Results

Among 457 individuals approached, 214 (47%) enrolled in the biorepository. A COVID-19 epidemiologic risk factor was recorded for 53%, and 15% lived in a US Centers for Disease Control and Prevention-defined COVID-19 hotspot. Individuals living in a COVID-19 hotspot (relative risk (RR) 2.4 [95% confidence interval (CI): 1.8–3.2]), with symptoms at presentation (RR 1.8 [95% CI: 1.2–2.7]), or admitted to hospital (RR 1.8 [95% CI: 1.2–2.8]) were more likely to enroll. Seventy-nine percent of enrollees donated any biospecimen, including 97 nasopharyngeal swabs, 119 oropharyngeal swabs, and 105 blood, 16 urine, and 16 stool specimens, respectively. Age, sex, race, ethnicity, and neighborhood-level socioeconomic status based on zip code did not predict enrollment or biospecimen donation.

Conclusions

While fewer than half of individuals approached consented to participate in the pediatric biorepository, enrollment appeared to be representative of children affected by the pandemic. Living in a COVID-19 hotspot, symptoms at presentation to care and hospital admission predicted biorepository enrollment. Once enrolled, most individuals donated a biospecimen.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-022-03185-6.

Biorepository - A key component of research studies

The last two decades have shown impressive advances in high-throughput assays for gene expression (genomics), proteins (proteomics), and metabolites (metabolomics). As a result, the quest for an equivalent need for human biological samples has increased exponentially. Translational investigations require good quality specimens to guarantee research results' integrity, probity, and reproducibility. A biorepository is a bank of specimens or specimens-derived neosamples (e.g., organoids, nucleic acids) linked to a database containing information related to these specimens. Two requirements must be met to safeguard the authenticity and stability of such a repository. First, the information provided should comprise relevant clinical and therapeutic communication, and second, the chain of custody is assured, guarded, versatile, and accessible. Completing these requirements is crucial for consistency, accuracy, verifiability, and disclosability of scientific and clinical outcomes. This commentary emphasizes that advocacy for standardization of operational workflows is a sine qua non for good science. Safe procedures for clinical trials are crucial to maintaining biorepositories' validity for all researchers.

Factors influencing precision medicine knowledge and attitudes

Precision medicine holds great promise for improving health and reducing health disparities that can be most fully realized by advancing diversity and inclusion in research participants. Without engaging underrepresented groups, precision medicine could not only fail to achieve its promise but also further exacerbate the health disparities already burdening the most vulnerable. Yet underrepresentation by people of non-European ancestry continues in precision medicine research and there are disparities across racial groups in the uptake of precision medicine applications and services. Studies have explored possible explanations for population differences in precision medicine participation, but full appreciation of the factors involved is still developing. To better inform the potential for addressing health disparities through PM, we assessed the relationship of precision medicine knowledge and trust in biomedical research with sociodemographic variables. Using a series of linear regression models applied to survey data collected in a diverse sample, we analyzed variation in both precision medicine knowledge and trust in biomedical research with socioeconomic factors as a way to understand the range of precision medicine knowledge (PMK) in a broadly representative group and its relationship to trust in research and demographic characteristics. Our results demonstrate that identifying as Black, while significantly PMK, explains only 1.5% of the PMK variance in unadjusted models and 7% of overall variance in models adjusted for meaningful covariates such as age, marital status, employment, and education. We also found a positive association between PMK and trust in biomedical research. These results indicate that race is a factor affecting PMK, even after accounting for differences in sociodemographic variables. Additional work is needed, however, to identify other factors contributing to variation in PMK as we work to increase diversity and inclusion in precision medicine applications.

Quality of whole genome sequencing from blood versus saliva derived DNA in cardiac patients

Background

Whole-genome sequencing (WGS) is becoming an increasingly important tool for detecting genomic variation. Blood derived DNA is the current standard for WGS for research or clinical purposes but may not always be feasible to acquire. The usability of DNA from saliva for WGS is not known. We compared the quality of WGS between blood versus saliva derived DNA.

Methods

WGS was performed in DNA from 531 blood and 502 saliva samples (including 5 paired samples) from participants enrolled in a heart disease biorepository. We compared the proportion of sequencing reads that mapped to non-human sources (microbiome), the sequencing coverage, and the yield and concordance of single nucleotide variant (SNV) and copy number variant (CNV) calls between blood and saliva genomes.

Results

Of 531 blood and 502 saliva samples, 46% saliva DNA failed quality control (QC) requirements for WGS compared to 6% QC failure for blood DNA. An average of 10.7% WGS reads in the saliva samples mapped to the human oral microbiome compared to 0.09% WGS reads in blood samples. However, these reads were readily excluded by excluding reads that did not map to the human reference genome. Sequencing coverage met or exceeded the target sequencing depth of 30x in all the blood samples and 4 of the 5 saliva samples; the fifth saliva sample had an average sequencing depth of 22.6x. Over 95% of SNVs identified in saliva were concordant with those identified in blood across the genome, within all gene coding regions, and within cardiovascular disease-related gene coding regions. Rare SNVs, defined as those with a minor allele frequency of less than 1% in the Genome Aggregation Database, had a lower concordance of 90% between blood and saliva genomes. CNVs had only 76% concordance between blood and saliva samples.

Conclusions

High quality saliva samples that meet stringent QC criteria can be used for WGS when blood-derived DNA is not available or is not suitable. Saliva DNA provides an acceptable yield of SNV calls but has a lower yield for CNV calls compared to blood DNA.

Return of genetic and genomic research findings: experience of a pediatric biorepository

Background

Assess process, uptake, validity and resource needs for return of actionable research findings to biobank participants.

Methods

Participants were prospectively enrolled in a multicenter biorepository of childhood onset heart disease. Clinically actionable research findings were reviewed by a Return of Research Results Committee (RRR) and returned to the physician or disclosed directly to the participant through a research genetic counselor. Action taken following receipt of this information was reviewed.

Results

Genetic data was generated in 1963 of 7408 participants. Fifty-nine new findings were presented to the RRR committee; 20 (34%) were deemed reportable. Twelve were returned to the physician, of which 7 were disclosed to participants (median time to disclosure, 192 days). Seven findings were returned to the research genetic counselor; all have been disclosed (median time to disclosure, 19 days). Twelve families (86%) opted for referral to clinical genetics after disclosure of findings; 7 results have been validated, 5 results are pending. Average cost of return and disclosure per reportable finding incurred by the research program was $750 when utilizing a research genetic counselor; clinical costs associated with return were not included.

Conclusions

Return of actionable research findings was faster if disclosed directly to the participant by a research genetic counselor. There was a high acceptability amongst participants for receiving the findings, for referral to clinical genetics, and for clinical validation of research findings, with all referred cases being clinically confirmed.

Consent for Genetic Biobanking in a Diverse Multisite CKD Cohort

Introduction

The goal of this study was to examine patterns in the likelihood of consent to genetic research among participants in a prospective kidney disease cohort and biobank, and to determine demographic, clinical, and socioeconomic factors linked to consent for ongoing and future genetic research.

Methods

The Clinical Phenotyping Resource and Biobank Core (C-PROBE) enrolled 1628 adult and pediatric patients with chronic kidney disease from 2009 to 2017 across 7 sites in the United States. Participants were asked at annual study visits for consent to provide DNA samples for future genetic studies. We compared characteristics of participants by initial consent outcome and consent status at their most recent study visit.

Results

Of the C-PROBE participants, 96% consented to genetic studies at their initial study visit. Although African Americans were slightly less likely to consent at baseline (93% vs. 97%, odds ratio = 0.3, P < 0.02), there were no significant racial or ethnic differences with longitudinal participation. Also, pediatric and adult genetic consent rates were equivalent. The major persistent differences in the likelihood of consent were based on enrollment site, which ranged from 85% to 100% (P < 0.0001).

Conclusion

Overall, genetic consent rates for kidney research within the C-PROBE cohort were high. However, differences in consent rates over time and by recruitment site highlight the complexity of genetic consent for biobanking, and potential limitations for generalizability of observations.

Avoiding false discovery in biomarker research

Background

Human tyrosine-protein phosphatase non-receptor type substrate 1α (SIRPA) is a surface marker identified in cardiomyocytes differentiated from human embryonic stem cells. Our objective was to determine if circulating SIRPA levels can serve as a biomarker of cardiac injury in children undergoing open heart surgery.

Results

Paired pre- and post-operative serum samples from 48 pediatric patients undergoing open heart surgery and from 6 pediatric patients undergoing non-cardiac surgery (controls) were tested for SIRPA protein levels using commercially available SIRPA ELISA kits from two manufacturers. Post-operative SIRPA concentrations were significantly higher in patients after cardiac surgery compared to non-cardiac surgery when tested using SIRPA ELISA kits from both manufacturers. To verify the identity of the protein detected, recombinant human SIRPA protein (rhSIRPA) was tested on both ELISA kits. The calibrator from both ELISA kits was analyzed by Western blot as well as by Mass Spectrometry (MS). Western blot analysis of calibrators from both kits did not identity SIRPA. MS analysis of calibrators from both ELISA kits identified several inflammatory markers and albumin but no SIRPA was detected.

Conclusions

We conclude that commercially available ELISA kits for SIRPA give false-positive results. Verifying protein identity using robust protein characterization is critical to avoid false biomarker discovery when using commercial ELISA kits.

Electronic supplementary material

The online version of this article (doi:10.1186/s12858-016-0073-x) contains supplementary material, which is available to authorized users.

Exome sequencing identifies rare variants in multiple genes in atrioventricular septal defect

Purpose

The genetic etiology of atrioventricular septal defect (AVSD) is unknown in 40% cases. Conventional sequencing and arrays have identified the etiology in only a minority of non-syndromic individuals with AVSD.

Methods

Whole exome sequencing was performed in 81 unrelated probands with AVSD to identify potentially causal variants in a comprehensive set of 112 genes with strong biological relevance to AVSD.

Results

A significant enrichment of rare and rare/damaging variants was identified in the gene set, compared with controls (odds ratio 1.52, 95% confidence interval 1.35–1.71, p = 4.8 x 10^-11). The enrichment was specific to AVSD probands compared with a non-AVSD cohort with tetralogy of Fallot (odds ratio 2.25, 95% confidence interval 1.84-2.76, p = 2.2 x 10^-16). Six genes (NIPBL, CHD7, CEP152, BMPR1a, ZFPM2 and MDM4) were enriched for rare variants in AVSD compared to controls, including three syndrome-associated genes (NIPBL, CHD7, CEP152). The findings were confirmed in a replication cohort of 81 AVSD probands.

Conclusion

Mutations in genes with strong biological relevance to AVSD, including syndrome-associated genes, can contribute to AVSD even in those with isolated heart disease. The identification of a gene set associated with AVSD will facilitate targeted genetic screening in this cohort.

High throughput exome coverage of clinically relevant cardiac genes

Background

Given the growing use of whole-exome sequencing (WES) for clinical diagnostics of complex human disorders, we evaluated coverage of clinically relevant cardiac genes on WES and factors influencing uniformity and depth of coverage of exonic regions.

Methods

Two hundred and thirteen human DNA samples were exome sequenced via Illumina HiSeq using different versions of the Agilent SureSelect capture kit. 50 cardiac genes were further analyzed including 31 genes from the American College of Medical Genetics (ACMG) list for reporting of incidental findings and 19 genes associated with congenital heart disease for which clinical testing is available. Gene coordinates were obtained from two databases, CCDS and Known Gene and compared. Read depth for each region was extracted from the exomes and used to assess capture variability between kits for individual genes, and for overall coverage. GC content, gene size, and inter-sample variability were also tested as potential contributors to variability in gene coverage.

Results

All versions of capture kits (designed based on Consensus coding sequence) included only 55% of known genomic regions for the cardiac genes. Although newer versions of each Agilent kit showed improvement in capture of CCDS regions to 99%, only 64% of Known Gene regions were captured even with newer capture kits. There was considerable variability in coverage of the cardiac genes. 10 of the 50 genes including 6 on the ACMG list had less than the optimal coverage of 30X. Within each gene, only 32 of the 50 genes had the majority of their bases covered at an interquartile range ≥30X. Heterogeneity in gene coverage was modestly associated with gene size and significantly associated with GC content.

Conclusions

Despite improvement in overall coverage across the exome with newer capture kit versions and higher sequencing depths, only 50% of known genomic regions of clinical cardiac genes are targeted and individual gene coverage is non-uniform. This may contribute to a bias with greater attribution of disease causation to mutations in well-represented and well-covered genes. Improvements in WES technology are needed before widespread clinical application.

Electronic supplementary material

The online version of this article (doi:10.1186/s12920-014-0067-8) contains supplementary material, which is available to authorized users.

Impact of prenatal risk factors on congenital heart disease in the current era

Background

The healthcare burden related to congenital heart disease (CHD) is increasing with improving survival. We assessed changing trends in prenatal risk factors for CHD in the current era in a Canadian cohort.

Methods and Results

CHD patients <18 years old (n=2339) and controls without structural heart disease (n=199) were prospectively enrolled in an Ontario province‐wide biobank registry from 2008–2011. Family history, frequency of extra‐cardiac anomalies (ECAs), and antenatal risk factors were assessed. Temporal trends were analyzed and associations with CHD were measured using linear and logistic regression. Family history of CHD and frequency of major ECAs was higher in cases versus controls (P<0.001). Despite an increase in genetic testing in the recent era, only 9.5% of cases with CHD had a confirmed genetic diagnosis. Yield of genetic testing (ie, frequency of abnormal results) was higher in familial and syndromic cases. There was an increase in parental age at conception, maternal prepregnancy body mass index, maternal urinary tract infections, type 1 diabetes, and exposure to nonfertility medications during pregnancy from 1990–2011. Later year of birth, family history of CHD, presence of major ECAs, maternal smoking during pregnancy, and maternal medication exposure were associated with increased odds of CHD (P<0.05 for all). Advanced parental age was associated with increased odds of CHD caused by genetic abnormalities.

Conclusions

The increase in prenatal risk factors for CHD highlights the need for more rigorous ascertainment of genetic and environmental factors including gene‐environment interactions that contribute to CHD.