Genetics of congenital heart disease: the glass half empty

Current and future diagnostics of congenital heart disease (CHD)

Congenital heart defects (CHD) are one of the most common anomalies found among live births and represent a complex multifactorial condition. Given that more than 90 % of cases survive due to improved early treatment options (e.g., catheter intervention, surgical procedure, and improved intensive care), genotype-informed patient follow-up should consider lifelong treatment considering different types of comorbidities. Unfortunately, a thorough genetic workup is only offered to a minority of CHD patients. However, a comprehensive understanding of the genetic underpinnings combined with in-depth phenotyping would strengthen our knowledge regarding the impact of environmental (e.g., pre-gestational diabetes) and genetic causes ranging from aneuploidies to single variants and more complex inheritance patterns on early heart development. Therefore, comprehensive genetic analysis in these patients is an essential way of predicting the prognosis and recurrence risk in families and ultimately improving patients' quality of life due to better therapeutic options. In this review, we examine the different types of variants and genes of different molecular genetics techniques to assess the diagnostic yield in different CHD sub-phenotypes. Given the complex inheritance pattern observed in CHD, we also consider possible future methods and frameworks to improve diagnostics and allow for better genotype-phenotype correlation in this patient group. Predicting recurrence risk and prognosis in CHD patients will ultimately allow for better treatment and lifelong therapeutic outcomes for CHD patients.

Role of Maternal Obesity in Offspring Cardiovascular Development and Congenital Heart Defects

BACKGROUND

Congenital heart disease is a leading cause of death in newborns, yet many of its molecular mechanisms remain unknown. Both maternal obesity and diabetes increase the risk of congenital heart disease in offspring, with recent studies suggesting these conditions may have distinct teratogenic mechanisms. The global prevalence of obesity is rising, and while maternal obesity is a known risk factor for fetal congenital heart disease, the specific mechanisms are largely unexplored.

METHODS AND RESULTS

We used a murine model of diet-induced maternal obesity, without diabetes, to produce dams that were overweight but had normal blood glucose levels. Embryos were generated and their developing hearts analyzed. Transcriptome analysis was performed using single-nucleus and bulk RNA sequencing. Global and phospho-enriched proteome analysis was performed using tandem mass tag-mass spectroscopy. Immunobloting and histologic evaluation were also performed. Analysis revealed disrupted oxidative phosphorylation and reactive oxygen species formation, with reduced antioxidant capacity, evidenced by downregulation of genes Sod1 and Gp4x, and disrupted Hif1a signaling. Evidence of oxidative stress, cell death signaling, and alteration in Rho GTPase and actin cytoskeleton signaling was also observed. Genes involved in cardiac morphogenesis, including Hand2, were downregulated, and fewer mature cardiomyocytes were present. Histologic analysis confirmed increased cardiac defects in embryos exposed to maternal obesity.

CONCLUSIONS

These findings demonstrate that maternal obesity alone can result in cardiac defects through mechanisms similar to those associated with maternal hyperglycemia. This study provides valuable insight into the role of maternal obesity, a growing and modifiable risk factor, in the development of the most common birth defect, congenital heart disease.

Dysmorphology-Based Prediction Model for Genetic Disorders in Infants With Congenital Heart Disease

BACKGROUND

Genetic disorders are prevalent in patients with congenital heart disease (CHD), but genetic evaluations are underutilized and nonstandardized. We sought to quantify a dysmorphology score and develop phenotype-based prediction models for genetic diagnoses in CHD.

METHODS

We used a test-negative case-control study of inpatient infants (<1 year) with CHD undergoing standardized genetic evaluations. We quantified a novel dysmorphology score and combined it with other clinical variables used in multivariable logistic regression models to predict genetic diagnoses identified by genetic testing.

RESULTS

Of 1008 patients, 24.1% (243/1008) had genetic diagnoses identified. About half of the cohort were either nondysmorphic or mildly dysmorphic with dysmorphology scores ≤2. There were higher dysmorphology scores according to CHD class (P=0.0007), extracardiac anomaly-positive status (P<0.0001), female sex (P=0.05), and genetic diagnosis identified (P<0.0001). Multivariable logistic regression models quantified this effect further: each +1 increase in the dysmorphology score was associated with a 17% to 20% increased risk of genetic diagnoses (odds ratios, 1.17-1.20, P<0.0001). Extracardiac anomaly-positive status remained a stronger predictor of genetic diagnoses (odds ratios, 2.81-3.39). Nonetheless, about 10% of the cohort were minimally dysmorphic (dysmorphology scores ≤2), had isolated CHD, and were found to have genetic diagnoses, indicating that dysmorphology-based screening can be used to risk-stratify but not exclude genetic diagnoses.

CONCLUSIONS

The dysmorphology score is a novel screen for patients with CHD at high risk of having genetic diagnoses identified by genetic testing, including disorders not easily recognized by clinicians. We used these results to develop predicted probability plots for genetic diagnoses in patients with CHD.

Molecular genetics of congenital heart disease

Congenital heart disease (CHD) is the most prevalent human birth defect and remains a leading cause of mortality in childhood. Although advancements in surgical and medical interventions have significantly reduced mortality rates among infants with critical CHDs, many survivors experience substantial cardiac and extracardiac comorbidities that affect their quality of life. The etiology of CHD is multifactorial, involving both genetic and environmental factors, yet a definitive cause remains unidentified in many cases. Recent advancements in genetic testing technologies have improved our ability to identify the genetic causes of CHD. This review presents an updated summary of the established genetic contributions to CHD, including chromosomal aberrations and mutations in genes associated with transcription factors, cardiac structural proteins, chromatin modifiers, cilia-related proteins, and cell signaling pathways. Furthermore, we discuss recent findings that support the roles of non-coding mutations and complex inheritance in the etiology of CHD.

GATA6 regulates WNT and BMP programs to pattern precardiac mesoderm during the earliest stages of human cardiogenesis

Haploinsufficiency for GATA6 is associated with congenital heart disease (CHD) with variable comorbidity of pancreatic or diaphragm defects, although the etiology of disease is not well understood. Here, we used cardiac directed differentiation from human embryonic stem cells (hESCs) as a platform to study GATA6 function during early cardiogenesis. GATA6 loss-of-function hESCs had a profound impairment in cardiac progenitor cell (CPC) specification and cardiomyocyte (CM) generation due to early defects during the mesendoderm and lateral mesoderm patterning stages. Profiling by RNA-seq and CUT&RUN identified genes of the WNT and BMP programs regulated by GATA6 during early mesoderm patterning. Furthermore, interactome analysis detected GATA6 binding with developmental transcription factors and chromatin remodelers, suggesting cooperative regulation of cardiac lineage gene accessibility. We show that modulating WNT and BMP inputs during the first 48 hr of cardiac differentiation is sufficient to partially rescue CPC and CM defects in GATA6 heterozygous and homozygous mutant hESCs. This study provides evidence of the regulatory functions for GATA6 directing human precardiac mesoderm patterning during the earliest stages of cardiogenesis to further our understanding of haploinsufficiency causing CHD and the co-occurrence of cardiac and other organ defects caused by human GATA6 mutations.

Deciphering the digenic architecture of congenital heart disease using trio exome sequencing data

Congenital heart disease (CHD) is the most common congenital anomaly and a leading cause of infant morbidity and mortality. Despite extensive exploration of the monogenic causes of CHD over the last decades, ∼55% of cases still lack a molecular diagnosis. Investigating digenic interactions, the simplest form of oligogenic interactions, using high-throughput sequencing data can elucidate additional genetic factors contributing to the disease. Here, we conducted a comprehensive analysis of digenic interactions in CHD by utilizing a large CHD trio exome sequencing cohort, comprising 3,910 CHD and 3,644 control trios. We extracted pairs of presumably deleterious rare variants observed in CHD-affected and unaffected children but not in a single parent. Burden testing of gene pairs derived from these variant pairs revealed 29 nominally significant gene pairs. These gene pairs showed a significant enrichment for known CHD genes (p < 1.0 × 10-4) and exhibited a shorter average biological distance to known CHD genes than expected by chance (p = 3.0 × 10-4). Utilizing three complementary biological relatedness approaches including network analyses, biological distance calculations, and candidate gene prioritization methods, we prioritized 10 final gene pairs that are likely to underlie CHD. Analysis of bulk RNA-sequencing data showed that these genes are highly expressed in the developing embryonic heart (p < 1 × 10-4). In conclusion, our findings suggest the potential role of digenic interactions in CHD pathogenesis and provide insights into unresolved molecular diagnoses. We suggest that the application of the digenic approach to additional disease cohorts will significantly enhance genetic discovery rates.

Development of machine learning-based models to predict congenital heart disease: A matched case-control study

BACKGROUND

The current congenital heart disease (CHD) prediction tools lack adequate interpretability and convenience, hindering the development of personalized CHD management strategies. We developed a machine learning-based risk stratification model for CHD prediction.

METHODS

This study utilized data from 1,759 participants in a case-control study of CHD conducted across six birth defects surveillance hospitals located in Xi'an, Shaanxi Province, Northwest China, spanning from January 2014 to December 2016. The data was partitioned into training and testing datasets with a ratio of 7:3. Predictors were selected from a total of 47 input variables through the Least Absolute Shrinkage and Selection Operator (LASSO). Five machine learning algorithms were used to build the CHD risk prediction models. Model performance was assessed based on a range of learning metrics, including the area under the receiver operating characteristic curve (AUROC), F1 score, and Brier score. Permutation feature importance was employed to elucidate the prediction model. The best-performing model was used to conduct the risk scores.

RESULTS

The eXtreme Gradient Boosting (XGB) model demonstrated superior performance among CHD prediction models, achieving an AUROC of 0.772 (95 % CI 0.728, 0.817) in the testing dataset and 0.738 (0.699, 0.775) in the external validation dataset. The pivotal predictors (top 3) identified by the model included living in rural areas, the low wealth index, and folic acid supplements (<90 days). The resultant risk score exhibited robust calibration capabilities. Utilizing the risk scores, participants were stratified into low, moderate, and high-risk categories, signifying substantial variations in CHD risk.

CONCLUSION

This study underscores the feasibility and efficacy of employing a machine learning-based approach for CHD prediction. The risk scores exhibited potential in identifying pregnant women at high risk for fetal CHD, offering valuable insights for guiding primary prevention and CHD management.

Whole-Exome Sequencing Identifies Novel GATA5/6 Variants in Right-Sided Congenital Heart Defects

One out of every hundred live births present with congenital heart abnormalities caused by the aberrant development of the embryonic cardiovascular system. The conserved zinc finger transcription factor proteins, which include GATA binding protein 5 (GATA5) and GATA binding protein (GATA6) play important roles in embryonic development and their inactivation may result in congenital heart defects (CHDs). In this study, we performed genotypic-phenotypic analyses in two families affected by right-sided CHD diagnosed by echocardiography imaging. Proband A presented with pulmonary valve stenosis, and proband B presented with complex CHD involving the right heart structures. For variant detection, we employed whole-genome single-nucleotide polymorphism (SNP) microarray and family-based whole-exome sequencing (WES) studies. Proband A is a full-term infant who was admitted to the neonatal intensive care unit (NICU) at five days of life for pulmonary valve stenosis (PVS). Genomic studies revealed a normal SNP microarray; however, quad WES analysis identified a novel heterozygous [Chr20:g.61041597C>G (p.Arg237Pro)] variant in the GATA5 gene. Further analysis confirmed that the novel variant was inherited from the mother but was absent in the father and the maternal uncle with a history of heart murmur. Proband B was born prematurely at 35 weeks gestation with a prenatally diagnosed complex CHD. A postnatal evaluation revealed right-sided heart defects including pulmonary atresia with intact ventricular septum (PA/IVS), right ventricular hypoplasia, tricuspid valve hypoplasia, hypoplastic main and bilateral branch pulmonary arteries, and possible coronary sinusoids. Cardiac catheterization yielded anatomy and hemodynamics unfavorable to repair. Hence, heart transplantation was indicated. Upon genomic testing, a normal SNP microarray was observed, while trio WES analysis identified a novel heterozygous [Chr18:c.1757C>T (p.Pro586Leu)] variant in the GATA6 gene. This variant was inherited from the father, who carries a clinical diagnosis of tetralogy of Fallot. These findings provide new insights into novel GATA5/6 variants, elaborate on the genotypic and phenotypic association, and highlight the critical role of GATA5 and GATA6 transcription factors in a wide spectrum of right-sided CHDs.

Developmental and Evolutionary Heart Adaptations Through Structure-Function Relationships

While the heart works as an efficient pump, it also has a high level of adaptivity by changing its structure to maintain function during healthy and diseased states. In this Review, we present examples of structure-function relationships across species and throughout embryonic development in mammals and birds. We also summarize current research on avian models aiming at understanding how biophysical and biological mechanisms closely interact during heart formation. We conclude by underscoring similarities between cardiac adaptations and structural changes over developmental and evolutionary time scales and how understanding the mechanisms behind these adaptations can help prevent or alleviate the effects of cardiac malformations and contribute to cardiac regeneration efforts.

Adaptor protein Src-homology 2 domain containing E (SH2E) deficiency induces heart defect in zebrafish

Adaptor proteins play crucial roles in signal transduction across diverse signaling pathways. Src-homology 2 domain-containing E (SH2E) is the adaptor protein highly expressed in vascular endothelial cells and myocardium during zebrafish embryogenesis. In this study we investigated the function and mechanisms of SH2E in cardiogenesis. We first analyzed the spatiotemporal expression of SH2E and then constructed zebrafish lines with SH2E deficiency using the CRISPR-Cas9 system. We showed that homozygous mutants developed progressive pericardial edema (PCE), dilated atrium, abnormal atrioventricular looping and thickened atrioventricular wall from 3 days post fertilization (dpf) until death; inducible overexpression of SH2E was able to partially rescue the PCE phenotype. Using transcriptome sequencing analysis, we demonstrated that the MAPK/ERK and NF-κB signaling pathways might be involved in SH2E-deficiency-caused PCE. This study underscores the pivotal role of SH2E in cardiogenesis, and might help to identify innovative diagnostic techniques and therapeutic strategies for congenital heart disease.

GATA6 regulates WNT and BMP programs to pattern precardiac mesoderm during the earliest stages of human cardiogenesis

Haploinsufficiency for GATA6 is associated with congenital heart disease (CHD) with variable comorbidity of pancreatic or diaphragm defects, although the etiology of disease is not well understood. Here, we used cardiac directed differentiation from human embryonic stem cells (hESCs) as a platform to study GATA6 function during early cardiogenesis. GATA6 loss-of-function hESCs had a profound impairment in cardiac progenitor cell (CPC) specification and cardiomyocyte (CM) generation due to early defects during the mesendoderm and lateral mesoderm patterning stages. Profiling by RNA-seq and CUT&RUN identified genes of the WNT and BMP programs regulated by GATA6 during early mesoderm patterning. Furthermore, interactome analysis detected GATA6 binding with developmental transcription factors and chromatin remodelers suggesting cooperative regulation of cardiac lineage gene accessibility. We show that modulating WNT and BMP inputs during the first 48 hours of cardiac differentiation is sufficient to partially rescue CPC and CM defects in GATA6 heterozygous and homozygous mutant hESCs. This study provides evidence of the regulatory functions for GATA6 directing human precardiac mesoderm patterning during the earliest stages of cardiogenesis to further our understanding of haploinsufficiency causing CHD and the co-occurrence of cardiac and other organ defects caused by human GATA6 mutations.

The polycomb protein complex interacts with GATA-6/PPARα to inhibit α-MHC expression

Transcription factors collaborate with epigenetic regulatory factors to orchestrate cardiac differentiation for heart development, but the underlying mechanism is not fully understood. Here, we report that GATA-6 induces cardiac differentiation but peroxisome proliferator-activated receptor α (PPARα) reverses GATA-6-induced cardiac differentiation, possibly because GATA-6/PPARα recruits the polycomb protein complex containing EZH2/Ring1b/BMI1 to the promoter of the cardiac-specific α-myosin heavy chain (α-MHC) gene and suppresses α-MHC expression, which ultimately inhibits cardiac differentiation. Furthermore, Ring1b ubiquitylates PPARα and GATA-6. By overexpression and knockout of EZH2/BMI1, it was demonstrated that the polycomb protein complex inhibits cardiac differentiation induced by GATA-6 and PPARα. Together, our results demonstrate that the polycomb protein complex interacts with GATA-6/PPARα to inhibit cardiac differentiation, a finding that could facilitate the development of new therapies for congenital heart disease.

Genetics of anomalies of the kidney and urinary tract with congenital heart disease: A review

Congenital anomalies of the kidney and urinary tract (CAKUT) and congenital heart disease (CHD) are the most common congenital defects and constitute a major cause of morbidity in children. Anomalies of both systems may be isolated or associated with congenital anomalies of other organ systems. Various reports support the co-occurrence of CAKUT and CHD, although the prevalence can vary. Cardiovascular anomalies occur in 11.2% to 34% of patients with CAKUT, and CAKUT occur in 5.3% to 35.8% of those with CHD. The co-occurrence of genetic factors in both CAKUT and CHD would raise common etiologies including genetics, genetic-environmental interactions, or shared molecular mechanisms and pathways such as NODAL, NOTCH, BMP, WNT, and VEGF. Studies in animal models and humans have indicated a genetic etiology for CHD and CAKUT with hundreds of genes recognized and thousands of entries, found in a catalog of human genetic disorders. There are over 80 CAKUT genes and over 100 CHD genes available for clinical testing. For example, the HNFIB gene accounts for 5% to 31% of reported cases of CAKUT. In view of the association between CAKUT and CHD, a thorough cardiac examination should be performed in patients with CAKUT, and a similar evaluation for CAKUT in the presence of CHD. This will allow early diagnosis and therapeutic intervention to improve the long- term outcome of patients affected, and test for at-risk family members. We present here evidence for an association of anomalies involving the two organ systems, and discuss possible etiologies of targeted genes, their functions, biological processes and interactions on embryogenesis.

Elevated microRNA-187 causes cardiac endothelial dysplasia to promote congenital heart disease through inhibition of NIPBL

Cardiac endothelial cells are essential for heart development, and disruption of this process can lead to congenital heart disease (CHD). However, how microRNAs influence cardiac endothelial cells in CHD remains unclear. This study identified elevated microRNA-187 (miR-187) expression in embryonic heart endothelial cells from CHD fetuses. Using a conditional knockin model, we showed that increased miR-187 levels in embryonic endothelial cells induce CHD in homozygous fetal mice, closely mirroring human CHD. Mechanistically, miR-187 targets NIPBL, which is responsible for recruiting the cohesin complex and facilitating chromatin accessibility. Consequently, the endothelial cell-specific upregulation of miR-187 inhibited NIPBL, leading to reduced chromatin accessibility and impaired gene expression, which hindered endothelial cell development and ultimately caused heart septal defects and reduced heart size both in vitro and in vivo. Importantly, exogenous miR-187 expression in human cardiac organoids mimicked developmental defects in the cardiac endothelial cells, and this was reversible by NIPBL replenishment. Our findings establish the miR-187/NIPBL axis as a potent regulator that inhibits cardiac endothelial cell development by attenuating the transcription of numerous endothelial genes, with our mouse and human cardiac organoid models effectively replicating severe defects from minor perturbations. This discovery suggests that targeting the miR-187/NIPBL pathway could offer a promising therapeutic approach for CHD.

Exploratory DNA methylation analysis in post-mortem heart tissue of sudden unexplained death

BACKGROUND

Sudden unexplained death (SUD) is a devastating event in the young. Despite efforts to identify causal genetic variants, many cases remain unexplained after genetic screening. This study aimed to investigate an alternative potential contributor to SUD by studying the human methylome using the MethylationEPIC v2.0 BeadChip kit in heart tissue from SUD cases. The genome-wide methylation results of the SUD cases were compared to the results of a control cohort. The SUD cases were divided into three main groups based on their autopsy reports, heart morphology and histopathology (primaryN: macroscopically and histologically normal heart; primaryCM: macroscopically or histologically abnormal heart, suspected cardiomyopathies; and secondary: myocardial damage due to other underlying conditions). The main focus of this study was to identify differentially methylated regions (DMRs) between the case groups and the control cohort.

RESULTS

We identified DMRs for both the primaryN and primaryCM groups, whereas the secondary group yielded no such results. In the primaryN cases, the corresponding genes for each DMR led to the identification of genes with common biological pathways. Some were associated with heart morphology (e.g. heart outflow tract morphogenesis or trabecular morphogenesis), but the majority belonged to more general cellular regulatory pathways (e.g. transcription coactivator activity, long non-coding RNAs, etc.). Although no common pathways were found for the primaryCM group, some common regulatory molecular functions were identified, such as p53 binding and transcription coactivator activity.

CONCLUSIONS

Our study is the first to investigate the whole human methylome in heart tissue of SUD cases. We propose that there are observable differences in the methylation patterns of the case groups that may have contributed to SUD. Still, further studies are required to improve our understanding of the impact of methylation levels on SUD risk and to pinpoint methylation-based screening opportunities for SUD relatives.

Single-cell multi-modal integrative analyses highlight functional dynamic gene regulatory networks directing human cardiac development

Illuminating the precise stepwise genetic programs directing cardiac development provides insights into the mechanisms of congenital heart disease and strategies for cardiac regenerative therapies. Here, we integrate in vitro and in vivo human single-cell multi-omic studies with high-throughput functional genomic screening to reveal dynamic, cardiac-specific gene regulatory networks (GRNs) and transcriptional regulators during human cardiomyocyte development. Interrogating developmental trajectories reconstructed from single-cell data unexpectedly reveal divergent cardiomyocyte lineages with distinct gene programs based on developmental signaling pathways. High-throughput functional genomic screens identify key transcription factors from inferred GRNs that are functionally relevant for cardiomyocyte lineages derived from each pathway. Notably, we discover a critical heat shock transcription factor 1 (HSF1)-mediated cardiometabolic GRN controlling cardiac mitochondrial/metabolic function and cell survival, also observed in fetal human cardiomyocytes. Overall, these multi-modal genomic studies enable the systematic discovery and validation of coordinated GRNs and transcriptional regulators controlling the development of distinct human cardiomyocyte populations.

Bioinformatic Multi-Strategy Profiling of Congenital Heart Defects for Molecular Mechanism Recognition

Congenital heart defects (CHDs) rank among the most common birth defects, presenting diverse phenotypes. Genetic and environmental factors are critical in molding the process of cardiogenesis. However, these factors' interactions are not fully comprehended. Hence, this study aimed to identify and characterize differentially expressed genes involved in CHD development through bioinformatics pipelines. We analyzed experimental datasets available in genomic databases, using transcriptome, gene enrichment, and systems biology strategies. Network analysis based on genetic and phenotypic ontologies revealed that EP300, CALM3, and EGFR genes facilitate rapid information flow, while NOTCH1, TNNI3, and SMAD4 genes are significant mediators within the network. Differential gene expression (DGE) analysis identified 2513 genes across three study types, (1) Tetralogy of Fallot (ToF); (2) Hypoplastic Left Heart Syndrome (HLHS); and (3) Trisomy 21/CHD, with LYVE1, PLA2G2A, and SDR42E1 genes found in three of the six studies. Interaction networks between genes from ontology searches and the DGE analysis were evaluated, revealing interactions in ToF and HLHS groups, but none in Trisomy 21/CHD. Through enrichment analysis, we identified immune response and energy generation as some of the relevant ontologies. This integrative approach revealed genes not previously associated with CHD, along with their interactions and underlying biological processes.

Prenatal detection of novel compound heterozygous variants of the PLD1 gene in a fetus with congenital heart disease

Background

Congenital heart disease (CHD) is the most common birth defect and heart valve defects are the most common cardiac defect, accounting for over 25% of all congenital heart diseases. To date, more than 400 genes have been linked to CHD, the genetic analysis of CHD cases is crucial for both clinical management and etiological determination. Patients with autosomal-recessive variants of PLD1 are predisposed to Cardiac Valvular Dysplasia-1 (CVDP1), which predominantly affects the right-sided heart valves, including the pulmonic, tricuspid, and mitral valves.

Methods

Databases were utilized to predict the impact of the c.1062-59A>G variant on splicing. Whole-exome sequencing (WES), reverse transcription polymerase chain reaction (RT-PCR), Sanger sequencing, and TA clone sequencing were conducted on both the parents and the fetus.

Results

A compound heterozygous variation in the PLD1(NM_002662.5):c.1937G>C (p. G646A) from the father and PLD1(NM_002662.5):c.1062-59A>G from the mother, was identified and confirmed in the fetus. The c.1937G>C (p. G646A) and the c.1062-59A>G variants were all classified as variant of uncertain significance (VUS) per ACMG guidelines. RT-PCR and TA clone sequencing revealed a 76-bp intronic insertion and exon 11 skipping in the proband and her mother's transcripts, causing a frameshift and premature stop codon in PLD1. Consequently, after being informed about the risks of their variant of unknown significance (VUS), the couple chose pre-implantation genetic testing for monogenic disorders (PGT-M) and had a healthy child.

Conclusion

Our study identified novel variants to expand the mutation spectrum of CHD and provided reliable evidence for the recurrent risk and reproductive care options.

Validation of a Paralimbic-Related Subcortical Brain Dysmaturation MRI Score in Infants with Congenital Heart Disease

Background: Brain magnetic resonance imaging (MRI) of infants with congenital heart disease (CHD) shows brain immaturity assessed via a cortical-based semi-quantitative score. Our primary aim was to develop an infant paralimbic-related subcortical-based semi-quantitative dysmaturation score, termed brain dysplasia score (BDS), to detect abnormalities in CHD infants compared to healthy controls and secondarily to predict clinical outcomes. We also validated our BDS in a preclinical mouse model of hypoplastic left heart syndrome. Methods: A paralimbic-related subcortical BDS, derived from structural MRIs of infants with CHD, was compared to healthy controls and correlated with clinical risk factors, regional cerebral volumes, feeding, and 18-month neurodevelopmental outcomes. The BDS was validated in a known CHD mouse model named Ohia with two disease-causing genes, Sap130 and Pchda9. To relate clinical findings, RNA-Seq was completed on Ohia animals. Findings: BDS showed high incidence of paralimbic-related subcortical abnormalities (including olfactory, cerebellar, and hippocampal abnormalities) in CHD infants (n = 215) compared to healthy controls (n = 92). BDS correlated with reduced cortical maturation, developmental delay, poor language and feeding outcomes, and increased length of stay. Ohia animals (n = 63) showed similar BDS findings, and RNA-Seq analysis showed altered neurodevelopmental and feeding pathways. Sap130 mutants correlated with a more severe BDS, whereas Pcdha9 correlated with a milder phenotype. Conclusions: Our BDS is sensitive to dysmaturational differences between CHD and healthy controls and predictive of poor outcomes. A similar spectrum of paralimbic and subcortical abnormalities exists between human and Ohia mutants, suggesting a common genetic mechanistic etiology.

Missense mutations in the CITED2 gene may contribute to congenital heart disease

BACKGROUND

Congenital heart disease (CHD) is a lifelong abnormality present from birth. Multiple studies have shown that mutations in genes involved in heart development could cause congenital heart disease. The CITED2 gene works as a transcription factor in the hypoxic pathway for the development of the heart. Therefore, five CHD types, ventricular septal defect, atrial septal defect, atrioventricular septal defect, tetralogy of fallot, and patent ductus arteriosus, were evaluated by conducting a targeted single nucleotide polymorphism (SNP) analysis of the CITED2 gene variant rs375393125 (T > C). This study aimed to identify the association of CITED2 gene mutations in CHD patients.

METHODS

Three hundred fifty samples, 250 from patients and 100 from controls, were collected for this genetic analysis. Allele-specific PCR and gel electrophoresis were used to identify the target missense mutations. The genotypic results of the CHDs were further validated through Sanger sequencing.

RESULTS

The frequency of the homozygous mutant (CC) in CHD patients was 48.4%, and of the heterozygous mutant (TC) genotype was 11.4%; these percentages are higher than controls (1%). The control samples had only one heterozygous TC and no homozygous CC genotype. The chi-square value was obtained at 103.9 with a probability of 0.05, more significant than the significance value of 21.03. The odds ratio was 43.7, which is > 1. The calculated value of ANOVA was 11.6, which was more significant than the F critical value of 3.7. As a result of sequencing, the mutant sample of each selected CHD type was found heterozygous or homozygous, and the results were like those obtained through conventional PCR.

CONCLUSION

The samples of CHD patients showed mutations. Therefore, the CITED2 gene SNP might be associated with CHD.

From genes to therapy: A comprehensive exploration of congenital heart disease through the lens of genetics and emerging technologies

Congenital heart disease (CHD) affects approximately 1 % of live births worldwide, making it the most common congenital anomaly in newborns. Recent advancements in genetics and genomics have significantly deepened our understanding of the genetics of CHDs. While the majority of CHD etiology remains unclear, evidence consistently indicates that genetics play a significant role in its development. CHD etiology holds promise for enhancing diagnosis and developing novel therapies to improve patient outcomes. In this review, we explore the contributions of both monogenic and polygenic factors of CHDs and highlight the transformative impact of emerging technologies on these fields. We also summarized the state-of-the-art techniques, including targeted next-generation sequencing (NGS), whole genome and whole exome sequencing (WGS, WES), single-cell RNA sequencing (scRNA-seq), human induced pluripotent stem cells (hiPSCs) and others, that have revolutionized our understanding of cardiovascular disease genetics both from diagnosis perspective and from disease mechanism perspective in children and young adults. These molecular diagnostic techniques have identified new genes and chromosomal regions involved in syndromic and non-syndromic CHD, enabling a more defined explanation of the underlying pathogenetic mechanisms. As our knowledge and technologies continue to evolve, they promise to enhance clinical outcomes and reduce the CHD burden worldwide.

Clinical and genetic associations of asymmetric apical and septal left ventricular hypertrophy

Aims

Increased left ventricular mass has been associated with adverse cardiovascular outcomes including incident cardiomyopathy and atrial fibrillation. Such associations have been studied in relation to total left ventricular hypertrophy, while the regional distribution of myocardial hypertrophy is extremely variable. The clinically significant and genetic associations of such variability require further study.

Methods and results

Here, we use deep learning-derived phenotypes of disproportionate patterns of hypertrophy, namely, apical and septal hypertrophy, to study genome-wide and clinical associations in addition to and independent from total left ventricular mass within 35 268 UK Biobank participants. Using polygenic risk score and Cox regression, we quantified the relationship between incident cardiovascular outcomes and genetically determined phenotypes in the UK Biobank. Adjusting for total left ventricular mass, apical hypertrophy is associated with elevated risk for cardiomyopathy and atrial fibrillation. Cardiomyopathy risk was increased for subjects with increased apical or septal mass, even in the absence of global hypertrophy. We identified 17 genome-wide associations for left ventricular mass, 3 unique associations with increased apical mass, and 3 additional unique associations with increased septal mass. An elevated polygenic risk score for apical mass corresponded with an increased risk of cardiomyopathy and implantable cardioverter-defibrillator implantation.

Conclusion

Apical and septal mass may be driven by genes distinct from total left ventricular mass, suggesting unique genetic profiles for patterns of hypertrophy. Focal hypertrophy confers independent and additive risk to incident cardiovascular disease. Our findings emphasize the significance of characterizing distinct subtypes of left ventricular hypertrophy. Further studies are needed in multi-ethnic cohorts.

Prenatal chromosomal microarray analysis in a large Chinese cohort of fetuses with congenital heart defects: a single center study

BACKGROUND AND OBJECTIVES

Congenital heart defect (CHD) is one of the most common birth defects. The aim of this cohort study was to evaluate the prevalence of chromosomal abnormalities and the clinical utility of chromosomal microarray analysis (CMA) in fetuses with different types of CHD, aiming to assist genetic counseling and clinical decision-making.

METHODS

In this study, 642 fetuses with CHD were enrolled from a single center over a six-year period (2017-2022). Both conventional karyotyping and CMA were performed simultaneously on these fetuses.

RESULTS

The diagnostic yield of CMA in fetuses with CHD in our study was 15.3% (98/642). Our findings revealed a significant increase in the diagnostic yield of CMA compared to karyotyping in fetuses with CHD. Among CHD subgroups, the diagnostic yields were high in complex CHD (34.9%), conotruncal defects (28.6%), right ventricular outflow tract obstructive defects (RVOTO) (25.9%), atrioventricular septal defects (AVSD) (25.0%) and left ventricular outflow tract obstructive defects (LVOTO) (24.1%), while those in other CHD (10.6%) and septal defects (10.9%) were relatively low. The overall detection rate of clinically significant chromosomal abnormalities was significantly higher in the non-isolated CHD group compared to the isolated CHD group (33.1% vs. 9.9%, P < 0.0001). Interestingly, numerical chromosomal abnormalities were more likely to occur in the non-isolated CHD group than in the isolated CHD group (20.3% vs. 2.0%, P < 0.0001). The rate of termination of pregnancy (TOP)/Still birth in the non-isolated CHD group was significantly higher than that in the isolated CHD group (40.5% vs. 20.6%, P < 0.0001). Compared to the isolated CHD group, the detection rate of clinically significant chromosomal abnormalities was significantly higher in the group of CHD with soft markers (35.6% vs. 9.9%, P < 0.0001) and in the group of CHD with additional structural anomalies (36.1% vs. 9.9%, P < 0.0001).

CONCLUSIONS

CMA is a reliable and high-resolution technique that should be recommended as the front-line test for prenatal diagnosis of fetuses with CHD. The prevalence of chromosomal abnormalities varies greatly among different subgroups of CHD, and special attention should be given to prenatal non-isolated cases of CHD, especially those accompanied by additional structural anomalies or soft markers.

ZCHSound: Open-Source ZJU Paediatric Heart Sound Database With Congenital Heart Disease

Congenital heart disease (CHD) is a common birth defect in children. Intelligent auscultation algorithms have been proven to reduce the subjectivity of diagnoses and alleviate the workload of doctors. However, the development of this algorithm has been limited by the lack of reliable, standardized, and publicly available pediatric heart sound databases. Therefore, the objective of this research is to develop a large-scale, high-standard, high-quality, and accurately labeled pediatric CHD heart sound database.

METHOD

From 2020 to 2022, we collaborated with experienced cardiac surgeons from three general children's hospitals to collect heart sound signals from 1259 participants using electronic stethoscopes. To ensure the accuracy of the labels, the labels for all data were confirmed by two cardiac experts. To establish the baseline of ZCHsound, we extracted 84 features and used machine learning models to evaluate the performance of the classification task.

RESULTS

The ZCHSound database was divided into two datasets: one is a high-quality, filtered clean heart sound dataset, and the other is a low-quality, noisy heart sound dataset. In the evaluation of the high-quality dataset, our random forest ensemble model achieved an F1 score of 90.3% in the classification task of normal and pathological heart sounds.

CONCLUSION

This study has successfully established a large-scale, high-quality, rigorously standardized pediatric CHD sound database with precise disease diagnosis. This database not only provides important learning resources for clinical doctors in auscultation knowledge but also offers valuable data support for algorithm engineers in developing intelligent auscultation algorithms.

The developmental processes of ventricular septal defects with outflow tract malalignment

Ventricular septal defects (VSD) with outflow tract (OFT) malalignment are a common group of congenital heart diseases with varying severity. The developmental process of these defects is challenging to understand due to the complex nature of cardiac morphogenesis and the difficulties in visualizing the temporal and spatial changes that occur during pathogenesis. However, recent advancements in imaging techniques, such as high-resolution episcopic microscopy, have provided valuable insights into the normal septation of ventricular chambers and OFT alignment. Building upon this knowledge, we have utilized lightsheet microscopy, another innovative imaging method, to further investigate the developmental processes that lead to abnormal formation of the ventricular septum and the malalignment of arterial roots with the ventricular chambers. Our study highlights endocardial cushion hypoplasia and insufficient rotation of the outflow tract as two interrelated central factors contributing to the pathogenesis of these defects. This finding has the potential to enhance our understanding of the etiology of congenital heart diseases and may contribute to the development of improved diagnostic and therapeutic strategies in the future.

Altered Inflammatory State and Mitochondrial Function Identified by Transcriptomics in Paediatric Congenital Heart Patients Prior to Surgical Repair

Congenital heart disease (CHD) remains the most common birth defect, with surgical intervention required in complex cases. Right ventricle (RV) function is known to be a major predictor of sustained cardiac health in these patients; thus, by elucidating the divergent profiles between CHD and the control through tissue analysis, this study aims to identify new avenues of investigation into the mechanisms surrounding reduced RV function. Transcriptomic profiling, in-silico deconvolution and functional network analysis were conducted on RV biopsies, identifying an increase in the mitochondrial dysfunction genes RPPH1 and RMPR (padj = 4.67 × 10-132, 2.23 × 10-107), the cytotoxic T-cell markers CD8a, LAGE3 and CD49a (p = 0.0006, p < 0.0001, and p = 0.0118) and proinflammatory caspase-1 (p = 0.0055) in CHD. Gene-set enrichment identified mitochondrial dysfunctional pathways, predominately changes within oxidative phosphorylation processes. The negative regulation of mitochondrial functions and metabolism was identified in the network analysis, with dysregulation of the mitochondrial complex formation. A histological analysis confirmed an increase in cellular bodies in the CHD RV tissue and positive staining for both CD45 and CD8, which was absent in the control. The deconvolution of bulk RNAseq data suggests a reduction in CD4+ T cells (p = 0.0067) and an increase in CD8+ T cells (p = 0.0223). The network analysis identified positive regulation of the immune system and cytokine signalling clusters in the inflammation functional network, as there were lymphocyte activation and leukocyte differentiation. Utilising RV tissue from paediatric patients undergoing CHD cardiac surgery, this study identifies dysfunctional mitochondrial pathways and an increase in inflammatory T-cell presence prior to reparative surgery.

Plasma metabolomic and lipidomic profiles accurately classify mothers of children with congenital heart disease: an observational study

INTRODUCTION

Congenital heart disease (CHD) is the most common congenital anomaly, representing a significant global disease burden. Limitations exist in our understanding of aetiology, diagnostic methodology and screening, with metabolomics offering promise in addressing these.

OBJECTIVE

To evaluate maternal metabolomics and lipidomics in prediction and risk factor identification for childhood CHD.

METHODS

We performed an observational study in mothers of children with CHD following pregnancy, using untargeted plasma metabolomics and lipidomics by ultrahigh performance liquid chromatography-high resolution mass spectrometry (UHPLC-HRMS). 190 cases (157 mothers of children with structural CHD (sCHD); 33 mothers of children with genetic CHD (gCHD)) from the children OMACp cohort and 162 controls from the ALSPAC cohort were analysed. CHD diagnoses were stratified by severity and clinical classifications. Univariate, exploratory and supervised chemometric methods were used to identify metabolites and lipids distinguishing cases and controls, alongside predictive modelling.

RESULTS

499 metabolites and lipids were annotated and used to build PLS-DA and SO-CovSel-LDA predictive models to accurately distinguish sCHD and control groups. The best performing model had an sCHD test set mean accuracy of 94.74% (sCHD test group sensitivity 93.33%; specificity 96.00%) utilising only 11 analytes. Similar test performances were seen for gCHD. Across best performing models, 37 analytes contributed to performance including amino acids, lipids, and nucleotides.

CONCLUSIONS

Here, maternal metabolomic and lipidomic analysis has facilitated the development of sensitive risk prediction models classifying mothers of children with CHD. Metabolites and lipids identified offer promise for maternal risk factor profiling, and understanding of CHD pathogenesis in the future.

Fetal circulatory physiology and brain development in complex congenital heart disease: A multi-modal imaging study

OBJECTIVE

Fetuses with complex congenital heart disease have altered physiology, contributing to abnormal neurodevelopment. The effects of altered physiology on brain development have not been well studied. We used multi-modal imaging to study fetal circulatory physiology and brain development in hypoplastic left heart syndrome (HLHS) and d-transposition of the great arteries (TGA).

METHODS

This prospective, cross-sectional study investigated individuals with fetal congenital heart disease and controls undergoing fetal echocardiography and fetal brain MRI. MRI measured total brain volume and cerebral oxygenation by the MRI quantification method T2*. Indexed cardiac outputs (CCOi) and vascular impedances were calculated by fetal echocardiography. Descriptive statistics assessed MRI and echocardiogram measurement relationships by physiology.

RESULTS

Sixty-six participants enrolled (control = 20; HLHS = 25; TGA = 21), mean gestational age 33.8 weeks (95% CI: 33.3-34.2). Total brain volume and T2* were significantly lower in fetuses with cardiac disease. CCOi was lower in HLHS, correlating with total brain volume - for every 10% CCOi increase, volume increased 8 mm3 (95% CI: 1.78-14.1; p = 0.012). Echocardiography parameters and cerebral oxygenation showed no correlation. TGA showed no CCOi or aortic output correlation with MRI measures.

CONCLUSIONS

In HLHS, lower cardiac output is deleterious to brain development. Our findings provide insight into the role of fetal cardiovascular physiology in brain health.

Current genetic models for studying congenital heart diseases: Advantages and disadvantages

Congenital heart disease (CHD) encompasses a diverse range of structural and functional anomalies that affect the heart and the major blood vessels. Epidemiological studies have documented a global increase in CHD prevalence, which can be attributed to advancements in diagnostic technologies. Extensive research has identified a plethora of CHD-related genes, providing insights into the biochemical pathways and molecular mechanisms underlying this pathological state. In this review, we discuss the advantages and challenges of various In vitro and in vivo CHD models, including primates, canines, Xenopus frogs, rabbits, chicks, mice, Drosophila, zebrafish, and induced pluripotent stem cells (iPSCs). Primates are closely related to humans but are rare and expensive. Canine models are costly but structurally comparable to humans. Xenopus frogs are advantageous because of their generation of many embryos, ease of genetic modification, and cardiac similarity. Rabbits mimic human physiology but are challenging to genetically control. Chicks are inexpensive and simple to handle; however, cardiac events can vary among humans. Mice differ physiologically, while being evolutionarily close and well-resourced. Drosophila has genes similar to those of humans but different heart structures. Zebrafish have several advantages, including high gene conservation in humans and physiological cardiac similarities but limitations in cross-reactivity with mammalian antibodies, gene duplication, and limited embryonic stem cells for reverse genetic methods. iPSCs have the potential for gene editing, but face challenges in terms of 2D structure and genomic stability. CRISPR-Cas9 allows for genetic correction but requires high technical skills and resources. These models have provided valuable knowledge regarding cardiac development, disease simulation, and the verification of genetic factors. This review highlights the distinct features of various models with respect to their biological characteristics, vulnerability to developing specific heart diseases, approaches employed to induce particular conditions, and the comparability of these species to humans. Therefore, the selection of appropriate models is based on research objectives, ultimately leading to an enhanced comprehension of disease pathology and therapy.

Spatial Distribution and Birth Prevalence of Congenital Heart Disease in Iran: A Systematic Review and Hierarchical Bayesian Meta-analysis

BACKGROUND

This study aimed to comprehensively analyze the overall congenital heart disease (CHD) prevalence in live births and children in Iran, along with evaluating the spatial distribution of CHD birth prevalence across various geographical regions within the country.

METHODS

A Bayesian hierarchical meta-analysis (PROSPERO 2022: CRD42022331281) was performed to determine the pooled prevalence. A systematic search was conducted using Web of Science, ScienceDirect, PubMed, Iranian Research Institute for Information Science and Technology (IranDoc), Scientific Information Database (SID), and Magiran until October 4, 2023. Cross-sectional and cohort studies in both English and Persian languages, focusing on the age range of 0-10 years, were considered for the study population. The study quality was evaluated using the Agency for Healthcare Research and Quality (AHRQ) Risk of Bias tool. Heterogeneity was assessed by I2 and τ2 statistics, and publication bias by Egger's and Begg's tests.

RESULTS

The meta-analysis included 62 studies, revealing an overall CHD prevalence of 2.5 per 1000 births. Over time, CHD birth prevalence in Iran has consistently increased. Spatial distribution analysis, including spatial autocorrelation and local spatial autocorrelation, indicated no spatial clustering (P=.46) or aggregation (P=.65) among Iran's provinces. Geographic disparities were significant (P=.000), with the northern and eastern regions showing the highest and lowest CHD prevalence, respectively.

CONCLUSION

The overall CHD prevalence in Iran is lower than global rates, but it continues to rise. Furthermore, there are variations in birth prevalence among different regions of Iran. Environmental, genetic, socioeconomic, and diagnostic accessibility differences are possibly involved in regional variation. The limitations like heterogeneity among studies, the potential inaccuracy of reports due to limited use of accurate diagnostic methods in some studies, and the absence of population-based models to investigate prevalence, underscore the urgent need for standardized diagnostic approaches, and the utilization of population-wide birth defect registries to accurately assess CHD prevalence in Iran.

Variants of the promoter of MYH6 gene in congenital isolated and sporadic patent ductus arteriosus: case-control study and cellular functional analyses

Patent ductus arteriosus (PDA) is a common form of congenital heart disease. The MYH6 gene has important effects on cardiovascular growth and development, but the effect of variants in the MYH6 gene promoter on ductus arteriosus is unknown. DNA was extracted from blood samples of 721 subjects (428 patients with isolated and sporadic PDA and 293 healthy controls) and analyzed by sequencing for MYH6 gene promoter region variants. Cellular function experiments with three cell lines (HEK-293, HL-1, and H9C2 cells) and bioinformatics analyses were performed to verify their effects on gene expression. In the MYH6 gene promoter, 11 variants were identified. Four variants were found only in patients with PDA and 2 of them (g.3434G>C and g.4524C>T) were novel. Electrophoretic mobility shift assay showed that the transcription factors bound by the promoter variants were significantly altered in comparison to the wild-type in all three cell lines. Dual luciferase reporter showed that all the 4 variants reduced the transcriptional activity of the MYH6 gene promoter (P < 0.05). Prediction of transcription factors bound by the variants indicated that these variants alter the transcription factor binding sites. These pathological alterations most likely affect the contraction of the smooth muscle of ductus arteriosus, leading to PDA. This study is the first to focus on variants at the promoter region of the MYH6 gene in PDA patients with cellular function tests. Therefore, this study provides new insights to understand the genetic basis and facilitates further studies on the mechanism of PDA formation.

Variants in FOXC1 and FOXC2 identified in patients with conotruncal heart defects

Conotruncal heart defects (CTD), subtypes of congenital heart disease, result from abnormal cardiac outflow tract development (OFT). FOXC1 and FOXC2 are closely related members of the forkhead transcription factor family and play essential roles in the development of OFT. We confirmed their expression pattern in mouse and human embryos, identifying four variants in FOXC1 and three in FOXC2 by screening these two genes in 605 patients with sporadic CTD. Western blot demonstrated expression levels, while Dual-luciferase reporter assay revealed affected transcriptional abilities for TBX1 enhancer in two FOXC1 variants and three FOXC2 variants. This might result from the altered DNA-binding abilities of mutant proteins. These results indicate that functionally impaired FOXC1 and FOXC2 variants may contribute to the occurrence of CTD.

Epigenetics of conotruncal congenital heart disease: Protocol for a systematic review and meta-analysis

BACKGROUND

Conotruncal congenital heart defects (CTD) are a subset of congenital heart diseases (CHD) that involve structural anomalies of the right, left, or both cardiac outflow tracts. CHD is caused by multifactorial inheritance and changes in the genes or chromosomes. Recently, CHD was found to be due to epigenetic alterations, which are a combination of genetic and other environmental factors. Epigenetics is the study of how a gene's function changes as a result of environmental and behavioral influences. These causative factors can indirectly cause CHD by altering the DNA through epigenetic modifications. This is a protocol for a systematic review and meta-analysis that aims to explore whether the strength of association between various epigenetic changes and CTD types varies by race. Furthermore, to determine and compare the changes in gene expression of each mutation.

METHODS

Our protocol follows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocol (PRISMA-P) guidelines. A comprehensive pre-search has been developed in PubMed and PubMed's Medical Subject Headings (MeSH). The final search will be performed in June 2023 in PubMed, Embase, Scopus, Web of Science, Cochrane Library, CIANHL, and PsycInfo, without restrictions on publication years. The Covidence systematic review software will be used for blinded screening and selection. Conflicts will be resolved by a third, independent reviewer. The risk of bias in selected studies will be assessed using the National Heart, Lung, and Blood Institute (NHLBI) Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. The data to be extracted will cover basic information on the included studies, study sample size, number of patients with various types of epigenetic changes, number of patients with various CTD types, measures of association and their 95% confidence interval between each epigenetic change and each CTD. The protocol has been registered with the International Prospero Register of Systematic Review (PROSPERO) [CRD42023377597].

DISCUSSION

To the best of our knowledge, this protocol outlines the first systematic review and meta-analysis of the epigenetics of CTD. There is a growing body of evidence on epigenetics and its indirect involvement in disease by altering the DNA through epigenetic modifications in the genes associated with the causative factors for CHD. We will conduct a comprehensive and systematic search for literature in the above-mentioned seven core biomedical databases. It is very important to identify population-specific risk factors for CHD, which will have significant creative, custom-made, and effective prevention programs for the future generation.

Polyoxyethylene tallow amine and glyphosate exert different developmental toxicities on human pluripotent stem cells-derived heart organoid model

The early stage of heart development is highly susceptible to various environmental factors. While the use of animal models has aided in identifying numerous environmental risk factors, the variability between species and the low throughput limit their translational potential. Recently, a type of self-assembling cardiac structures, known as human heart organoids (hHOs), exhibits a remarkable biological consistency with human heart. However, the feasibility of hHOs for assessing cardiac developmental risk factors remains unexplored. Here, we focused on the cardiac developmental effects of core components of Glyphosate-based herbicides (GBHs), the most widely used herbicides, to evaluate the reliability of hHOs for the prediction of possible cardiogenesis toxicity. GBHs have been proven toxic to cardiac development based on multiple animal models, with the mechanism remaining unknown. We found that polyoxyethylene tallow amine (POEA), the most common surfactant in GBHs formulations, played a dominant role in GBHs' heart developmental toxicity. Though there were a few differences in transcriptive features, hHOs exposed to sole POEA and combined POEA and Glyphosate would suffer from both disruption of heart contraction and disturbance of commitment in cardiomyocyte isoforms. By contrast, Glyphosate only caused mild epicardial hyperplasia. This study not only sheds light on the toxic mechanism of GBHs, but also serves as a methodological demonstration, showcasing its effectiveness in recognizing and evaluating environmental risk factors, and deciphering toxic mechanisms.

Understanding the Genetic and Non-genetic Interconnections in the Aetiology of Isolated Congenital Heart Disease: An Updated Review: Part 1

PURPOSE OF REVIEW

Congenital heart disease (CHD) is the most frequently occurring birth defect. Majority of the earlier reviews focussed on the association of genetic factors with CHD. A few epidemiological studies provide convincing evidence for environmental factors in the causation of CHD. Although the multifactorial theory of gene-environment interaction is the prevailing explanation, explicit understanding of the biological mechanism(s) involved, remains obscure. Nonetheless, integration of all the information into one platform would enable us to better understand the collective risk implicated in CHD development.

RECENT FINDINGS

Great strides in novel genomic technologies namely, massive parallel sequencing, whole exome sequencing, multiomics studies supported by system-biology have greatly improved our understanding of the aetiology of CHD. Molecular genetic studies reveal that cardiac specific gene variants in transcription factors or signalling molecules, or structural proteins could cause CHD. Additionally, non-hereditary contributors such as exposure to teratogens, maternal nutrition, parental age and lifestyle factors also contribute to induce CHD. Moreover, DNA methylation and non-coding RNA are also correlated with CHD. Here, we inform that a complex combination of genetic, environmental and epigenetic factors interact to interfere with morphogenetic processes of cardiac development leading to CHD. It is important, not only to identify individual genetic and non-inherited risk factors but also to recognize which factors interact mutually, causing cardiac defects.

Analysis of the Association between Copy Number Variation and Ventricular Fibrillation in ST-Elevation Acute Myocardial Infarction

Sudden cardiac death due to ventricular fibrillation (VF) during ST-elevation acute myocardial infarction (STEAMI) significantly contributes to cardiovascular-related deaths. Although VF has been linked to genetic factors, variations in copy number variation (CNV), a significant source of genetic variation, have remained largely unexplored in this context. To address this knowledge gap, this study performed whole exome sequencing analysis on a cohort of 39 patients with STEAMI who experienced VF, aiming to elucidate the role of CNVs in this pathology. The analysis revealed CNVs in the form of duplications in the PARP2 and TTC5 genes as well as CNVs in the form of deletions in the MUC15 and PPP6R1 genes, which could potentially serve as risk indicators for VF during STEAMI. The analysis also underscores notable CNVs with an average gene copy number equal to or greater than four in DEFB134, FCGR2C, GREM1, PARM1, SCG5, and UNC79 genes. These findings provide further insight into the role of CNVs in VF in the context of STEAMI.

Genetics and etiology of congenital heart disease

Congenital heart disease (CHD) is the most common severe birth anomaly, affecting almost 1% of infants. Most CHD is genetic, but only 40% of patients have an identifiable genetic risk factor for CHD. Chromosomal variation contributes significantly to CHD but is not readily amenable to biological follow-up due to the number of affected genes and lack of evolutionary synteny. The first CHD genes were implicated in extended families with syndromic CHD based on the segregation of risk alleles in affected family members. These have been complemented by more CHD gene discoveries in large-scale cohort studies. However, fewer than half of the 440 estimated human CHD risk genes have been identified, and the molecular mechanisms underlying CHD genetics remains incompletely understood. Therefore, model organisms and cell-based models are essential tools for improving our understanding of cardiac development and CHD genetic risk. Recent advances in genome editing, cell-specific genetic manipulation of model organisms, and differentiation of human induced pluripotent stem cells have recently enabled the characterization of developmental stages. In this chapter, we will summarize the latest studies in CHD genetics and the strengths of various study methodologies. We identify opportunities for future work that will continue to further CHD knowledge and ultimately enable better diagnosis, prognosis, treatment, and prevention of CHD.

The role of metabolism in cardiac development

Metabolism is the fundamental process that sustains life. The heart, in particular, is an organ of high energy demand, and its energy substrates have been studied for more than a century. In recent years, there has been a growing interest in understanding the role of metabolism in the early differentiation of pluripotent stem cells and in cancer research. Studies have revealed that metabolic intermediates from glycolysis and the tricarboxylic acid cycle act as co-factors for intracellular signal transduction, playing crucial roles in regulating cell behaviors. Mitochondria, as the central hub of metabolism, are also under intensive investigation regarding the regulation of their dynamics. The metabolic environment of the fetus is intricately linked to the maternal metabolic status, and the impact of the mother's nutrition and metabolic health on fetal development is significant. For instance, it is well known that maternal diabetes increases the risk of cardiac and nervous system malformations in the fetus. Another notable example is the decrease in the risk of neural tube defects when pregnant women are supplemented with folic acid. These examples highlight the profound influence of the maternal metabolic environment on the fetal organ development program. Therefore, gaining insights into the metabolic environment within developing fetal organs is critical for deepening our understanding of normal organ development. This review aims to summarize recent findings that build upon the historical recognition of the environmental and metabolic factors involved in the developing embryo.

A Pilot Study of Multiplex Ligation-Dependent Probe Amplification Evaluation of Copy Number Variations in Romanian Children with Congenital Heart Defects

Congenital heart defects (CHDs) have had an increasing prevalence over the last decades, being one of the most common congenital defects. Their etiopathogenesis is multifactorial in origin. About 10-15% of all CHD can be attributed to copy number variations (CNVs), a type of submicroscopic structural genetic alterations. The aim of this study was to evaluate the involvement of CNVs in the development of congenital heart defects. We performed a cohort study investigating the presence of CNVs in the 22q11.2 region and GATA4, TBX5, NKX2-5, BMP4, and CRELD1 genes in patients with syndromic and isolated CHDs. A total of 56 patients were included in the study, half of them (28 subjects) being classified as syndromic. The most common heart defect in our study population was ventricular septal defect (VSD) at 39.28%. There were no statistically significant differences between the two groups in terms of CHD-type distribution, demographical, and clinical features, with the exceptions of birth length, weight, and length at the time of blood sampling, that were significantly lower in the syndromic group. Through multiplex ligation-dependent probe amplification (MLPA) analysis, we found two heterozygous deletions in the 22q11.2 region, both in patients from the syndromic group. No CNVs involving GATA4, NKX2-5, TBX5, BMP4, and CRELD1 genes were identified in our study. We conclude that the MLPA assay may be used as a first genetic test in patients with syndromic CHD and that the 22q11.2 region may be included in the panels used for screening these patients.

In-Depth Genomic Analysis: The New Challenge in Congenital Heart Disease

The use of next-generation sequencing has provided new insights into the causes and mechanisms of congenital heart disease (CHD). Examinations of the whole exome sequence have detected detrimental gene variations modifying single or contiguous nucleotides, which are characterised as pathogenic based on statistical assessments of families and correlations with congenital heart disease, elevated expression during heart development, and reductions in harmful protein-coding mutations in the general population. Patients with CHD and extracardiac abnormalities are enriched for gene classes meeting these criteria, supporting a common set of pathways in the organogenesis of CHDs. Single-cell transcriptomics data have revealed the expression of genes associated with CHD in specific cell types, and emerging evidence suggests that genetic mutations disrupt multicellular genes essential for cardiogenesis. Metrics and units are being tracked in whole-genome sequencing studies.

Human Genetics of Defects of Situs

Defects of situs are associated with complex sets of congenital heart defects in which the normal concordance of asymmetric thoracic and abdominal organs is disturbed. The cellular and molecular mechanisms underlying the formation of the embryonic left-right axis have been investigated extensively in the past decade. This has led to the identification of mutations in at least 33 different genes in humans with heterotaxy and situs defects. Those mutations affect a broad range of molecular components, from transcription factors, signaling molecules, and chromatin modifiers to ciliary proteins. A substantial overlap of these genes is observed with genes associated with other congenital heart diseases such as tetralogy of Fallot and double-outlet right ventricle, d-transposition of the great arteries, and atrioventricular septal defects. In this chapter, we present the broad genetic heterogeneity of situs defects including recent human genomics efforts.

Human Genetics of Tetralogy of Fallot and Double-Outlet Right Ventricle

Tetralogy of Fallot (TOF) and double-outlet right ventricle (DORV) are conotruncal defects resulting from disturbances of the second heart field and the neural crest, which can occur as isolated malformations or as part of multiorgan syndromes. Their etiology is multifactorial and characterized by overlapping genetic causes. In this chapter, we present the different genetic alterations underlying the two diseases, which range from chromosomal abnormalities like aneuploidies and structural mutations to rare single nucleotide variations affecting distinct genes. For example, mutations in the cardiac transcription factors NKX2-5, GATA4, and HAND2 have been identified in isolated TOF cases, while mutations of TBX5 and 22q11 deletion, leading to haploinsufficiency of TBX1, cause Holt-Oram and DiGeorge syndrome, respectively. Moreover, genes involved in signaling pathways, laterality determination, and epigenetic mechanisms have also been found mutated in TOF and/or DORV patients. Finally, genome-wide association studies identified common single nucleotide polymorphisms associated with the risk for TOF.

Genomic insights into heart health: Exploring the genetic basis of cardiovascular disease

Cardiovascular diseases (CVDs) are considered as the leading cause of death worldwide. CVD continues to be a major cause of death and morbidity despite significant improvements in its detection and treatment. Therefore, it is strategically important to be able to precisely characterize an individual's sensitivity to certain illnesses. The discovery of genes linked to cardiovascular illnesses has benefited from linkage analysis and genome-wide association research. The last 20 years have seen significant advancements in the field of molecular genetics, particularly with the development of new tools like genome-wide association studies. In this article we explore the profound impact of genetic variations on disease development, prognosis, and therapeutic responses. And the significance of genetics in cardiovascular risk assessment and the ever-evolving realm of genetic testing, offering insights into the potential for personalized medicine in this domain. Embracing the future of cardiovascular care, the article explores the implications of pharmacogenomics for tailored treatments, the promise of emerging technologies in cardiovascular genetics and therapies, including the transformative influence of nanotechnology. Furthermore, it delves into the exciting frontiers of gene editing, such as CRISPR/Cas9, as a novel approach to combat cardiovascular diseases. And also explore the potential of stem cell therapy and regenerative medicine, providing a holistic view of the dynamic landscape of cardiovascular genomics and its transformative potential for the field of cardiovascular medicine.

Whole exome sequencing reveals genetic landscape associated with left ventricular outflow tract obstruction in Chinese Han population

Left ventricular outflow tract obstruction (LVOTO), a major form of outflow tract malformation, accounts for a substantial portion of congenital heart defects (CHDs). Unlike its prevalence, the genetic architecture of LVOTO remains largely unknown. To unveil the genetic mutations and risk genes potentially associated with LVOTO, we enrolled a cohort of 106 LVOTO patients and 100 healthy controls and performed a whole-exome sequencing (WES). 71,430 rare deleterious mutations were found in LVOTO patients. By using gene-based burden testing, we further found 32 candidate genes enriched in LVOTO patient including known pathological genes such as GATA5 and GATA6. Most variants of 32 risk genes occur simultaneously rather exclusively suggesting polygenic inherence of LVOTO and 14 genes out of 32 risk genes interact with previously discovered CHD genes. Single cell RNA-seq further revealed dynamic expressions of GATA5, GATA6, FOXD3 and MYO6 in endocardium and neural crest lineage indicating the mutations of these genes lead to LVOTO possibly through different lineages. These findings uncover the genetic architecture of LVOTO which advances the current understanding of LVOTO genetics.

Transcriptome studies of congenital heart diseases: identifying current gaps and therapeutic frontiers

Congenital heart disease (CHD) are genetically complex and comprise a wide range of structural defects that often predispose to - early heart failure, a common cause of neonatal morbidity and mortality. Transcriptome studies of CHD in human pediatric patients indicated a broad spectrum of diverse molecular signatures across various types of CHD. In order to advance research on congenital heart diseases (CHDs), we conducted a detailed review of transcriptome studies on this topic. Our analysis identified gaps in the literature, with a particular focus on the cardiac transcriptome signatures found in various biological specimens across different types of CHDs. In addition to translational studies involving human subjects, we also examined transcriptomic analyses of CHDs in a range of model systems, including iPSCs and animal models. We concluded that RNA-seq technology has revolutionized medical research and many of the discoveries from CHD transcriptome studies draw attention to biological pathways that concurrently open the door to a better understanding of cardiac development and related therapeutic avenue. While some crucial impediments to perfectly studying CHDs in this context remain obtaining pediatric cardiac tissue samples, phenotypic variation, and the lack of anatomical/spatial context with model systems. Combining model systems, RNA-seq technology, and integrating algorithms for analyzing transcriptomic data at both single-cell and high throughput spatial resolution is expected to continue uncovering unique biological pathways that are perturbed in CHDs, thus facilitating the development of novel therapy for congenital heart disease.

A germline chimeric KANK1-DMRT1 transcript derived from a complex structural variant is associated with a congenital heart defect segregating across five generations

Structural variants (SVs) pose a challenge to detect and interpret, but their study provides novel biological insights and molecular diagnosis underlying rare diseases. The aim of this study was to resolve a 9p24 rearrangement segregating in a family through five generations with a congenital heart defect (congenital pulmonary and aortic valvular stenosis, and pulmonary artery stenosis), by applying a combined genomic analysis. The analysis involved multiple techniques, including karyotype, chromosomal microarray analysis (CMA), FISH, whole-genome sequencing (WGS), RNA-seq and optical genome mapping (OGM). A complex 9p24 SV was hinted at by CMA results, showing three interspersed duplicated segments. Combined WGS and OGM analyses revealed that the 9p24 duplications constitute a complex SV, on which a set of breakpoints match the boundaries of the CMA duplicated sequences. The proposed structure for this complex rearrangement implies three duplications associated with an inversion of ~ 2Mb region on chromosome 9 with a SINE element insertion at the more distal breakpoint. Interestingly, this hypothesized genomic structure of rearrangement forms a chimeric transcript of the KANK1/DMRT1 loci, which was confirmed by RNA-seq on blood from 9p24 rearrangement carriers. Altogether with breakpoint amplification and FISH analysis, this combined approach allowed a deep characterization of this complex rearrangement. Although the genotype-phenotype correlation remains elusive from the molecular mechanism point of view, this study identified a large genomic rearrangement at 9p segregating with a familial congenital clinical trait, revealing a genetic biomarker that was successfully applied for embryo selection, changing the reproductive perspective of affected individuals.

The comprehensive study on the role of POSTN in fetal congenital heart disease and clinical applications

BACKGROUND

Congenital heart defect (CHD) is the most common congenital abnormality, and it has long been a clinical and public health concern. Our previous findings have found Periostin (POSTN) and Pappalysin-1 (PAPPA) as potential biomarkers for fetal CHD. We aim to further elucidate POSTN's role in fetal heart development and explore the clinical applicability of POSTN and PAPPA as diagnostic marker for fetal CHD. This study is poised to establish a theoretical framework for mitigating the incidence of CHD and advance a novel approach for prenatal screening of fetal CHD.

METHODS

We verified differential expression of POSTN and PAPPA in gravida serum and fetal amniotic fluid based on our previous research. We established the Postn knockout mouse by CRISPR/Cas9 to investigate whether Postn deletion leads to cardiac abnormalities in mice. Besides, we explored the mechanism of POSTN on heart development through Postn knockout mouse model and cell experiments. Finally, we established the logistic regression model and decision curve analysis to evaluate the clinical utility of POSTN and PAPPA in fetal CHD.

RESULTS

We observed a significant decrease in POSTN and increase in PAPPA in the CHD group. Atrial septal defects occurred in Postn-/- and Postn± C57BL/6 fetal heart, while ventricular septal defects with aortic saddle were observed in Postn± C57BL/6 fetal heart. Disruption of the extracellular matrix (ECM) in cardiomyocytes and multiple abnormalities in cellular sub-organelles were observed in Postn knockout mice. POSTN may positively regulate cell behaviors and unsettle ECM via the TGFβ-Smad2/3 signaling pathway. The combination of serum biomarkers POSTN and PAPPA with Echocardiogram can enhance the diagnostic accuracy of CHD. Furthermore, the comprehensive model including POSTN, PAPPA, and two clinical indicators (NT and age) exhibits significantly higher predictive ability than the diagnosis group without the use of serum biomarkers or clinical indicators.

CONCLUSIONS

It is the first evidence that Postn deletion leads to cardiac developmental abnormalities in fetal mice. This may involve the regulation of the TGFβ signaling pathway. Importantly, POSTN and PAPPA possess clinical utility as noninvasive prenatal promising screening indicators of CHD.

Biological Age in Congenital Heart Disease-Exploring the Ticking Clock

Over the past 50 years, there has been a major shift in age distribution of patients with congenital heart disease (CHD) thanks to significant advancements in medical and surgical treatment. Patients with CHD are, however, never cured and face unique challenges throughout their lives. In this review, we discuss the growing data suggesting accelerated aging in this population. Adults with CHD are more often and at a younger age confronted with age-related cardiovascular complications such as heart failure, arrhythmia, and coronary artery disease. These can be related to the original birth defect, complications of correction, or any residual defects. In addition, and less deductively, more systemic age-related complications are seen earlier, such as renal dysfunction, lung disease, dementia, stroke, and cancer. The occurrence of these complications at a younger age makes it imperative to further map out the aging process in patients across the spectrum of CHD. We review potential feasible markers to determine biological age and provide an overview of the current data. We provide evidence for an unmet need to further examine the aging paradigm as this stresses the higher need for care and follow-up in this unique, newly aging population. We end by exploring potential approaches to improve lifespan care.

Multi-chamber cardioids unravel human heart development and cardiac defects

The number one cause of human fetal death are defects in heart development. Because the human embryonic heart is inaccessible and the impacts of mutations, drugs, and environmental factors on the specialized functions of different heart compartments are not captured by in vitro models, determining the underlying causes is difficult. Here, we established a human cardioid platform that recapitulates the development of all major embryonic heart compartments, including right and left ventricles, atria, outflow tract, and atrioventricular canal. By leveraging 2D and 3D differentiation, we efficiently generated progenitor subsets with distinct first, anterior, and posterior second heart field identities. This advance enabled the reproducible generation of cardioids with compartment-specific in vivo-like gene expression profiles, morphologies, and functions. We used this platform to unravel the ontogeny of signal and contraction propagation between interacting heart chambers and dissect how mutations, teratogens, and drugs cause compartment-specific defects in the developing human heart.

An Assessment of the Therapeutic Landscape for the Treatment of Heart Disease in the RASopathies

The RAS/mitogen-activated protein kinase (MAPK) pathway controls a plethora of developmental and post-developmental processes. It is now clear that mutations in the RAS-MAPK pathway cause developmental diseases collectively referred to as the RASopathies. The RASopathies include Noonan syndrome, Noonan syndrome with multiple lentigines, cardiofaciocutaneous syndrome, neurofibromatosis type 1, and Costello syndrome. RASopathy patients exhibit a wide spectrum of congenital heart defects (CHD), such as valvular abnormalities and hypertrophic cardiomyopathy (HCM). Since the cardiovascular defects are the most serious and recurrent cause of mortality in RASopathy patients, it is critical to understand the pathological signaling mechanisms that drive the disease. Therapies for the treatment of HCM and other RASopathy-associated comorbidities have yet to be fully realized. Recent developments have shown promise for the use of repurposed antineoplastic drugs that target the RAS-MAPK pathway for the treatment of RASopathy-associated HCM. However, given the impact of the RAS-MAPK pathway in post-developmental physiology, establishing safety and evaluating risk when treating children will be paramount. As such insight provided by preclinical and clinical information will be critical. This review will highlight the cardiovascular manifestations caused by the RASopathies and will discuss the emerging therapies for treatment.