A Screening Approach to Identify Clinically Actionable Variants Causing Congenital Heart Disease in Exome Data

Evaluation of Exome and Genome Sequencing for Critically Ill Pediatric Cardiac Patients

Genetic testing guidelines for children in cardiac intensive care units (CICUs) are lacking despite a high prevalence of genetic diseases among this population. Advances in next-generation sequencing (NGS) technologies, especially exome and genome sequencing (ES/GS), enable a more comprehensive genetic evaluation than more traditional testing modalities such as chromosomal microarray (CMA). While testing recommendations exist for cardiomyopathies, primary arrhythmias, and pulmonary hypertension (PH), broad application of NGS, especially ES/GS, across indications for admission to CICUs has not been recommended. We aimed to evaluate the diagnostic efficacy of ES/GS in critically ill pediatric patients with cardiac disease via a retrospective chart review of patients who underwent clinical ES/GS in a quaternary hospital's pediatric CICU between January 2020 and August 2023. Forty-nine patients underwent ES/GS. Primary cardiac phenotypes included congenital heart disease, ventricular dysfunction, arrhythmia, and PH. Diagnostic results were found in 22 patients (44.9%) with 18/22 (81.8%) linked to cardiac phenotypes. Diagnostic yield was not different among primary cardiac phenotype groups but was higher in patients with ECA. CMA and gene panels would have failed to make a substantial proportion (80.6% and 36%, respectively) of diagnoses made by ES/GS. As NGS technologies and capabilities to interpret ES/GS data mature, diagnostic abilities in pediatric cardiac disease will continue to advance.

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.

Association Study of MTHFR C677T Polymorphism With Homocysteine Level and Coronary Heart Disease in Elderly Patients

Objective: To investigate the relationship between methylenetetrahydrofolate reductase (MTHFR) C677T gene polymorphism and coronary heart disease (CHD) in the elderly patients living in the coastal area of eastern Zhejiang Province in China. Methods: From September 2021 to May 2022, 163 elderly patients (male ≥ 55 years old, female ≥ 65 years old) admitted to the cardiology department in the Ningbo Lihuili Hospital were collected. Among these patients, 90 patients were diagnosed with CHD (CHD group) and 79 patients did not have CHD (control group). The homocysteine (Hcy) level was measured by the blood biochemical test, and the MTHFR genotype was detected by the PCR fluorescence probe method. Results: Compared with the control group, the CHD group showed a significantly higher distribution frequency of TT genotype (X 2 = 5.137, p < 0.05) and a lower frequency of CC genotype (X 2 = 6.560, p < 0.05), indicating that elderly people with MTHFR677 TT genotype are more likely to have CHD. In addition, the Hcy level of TT genotype in the CHD group and the control group were both obviously higher than that of CT genotype and CC genotype (p < 0.05). Finally, the univariate and multivariate logistic regression analyses showed that gender, hypertension, diabetes, and MTHFR677 TT genotype were independent risk factors for CHD (p < 0.05). Conclusion: MTHFR C677T mutation is significantly associated with the serum Hcy, and is an important genetic risk for CHD development in the elderly people living in the coastal area of eastern Zhejiang province, China.

2025 Heart Disease and Stroke Statistics: A Report of US and Global Data From the American Heart Association

BACKGROUND

The American Heart Association (AHA), in conjunction with the National Institutes of Health, annually reports the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, nutrition, sleep, and obesity) and health factors (cholesterol, blood pressure, glucose control, and metabolic syndrome) that contribute to cardiovascular health. The AHA Heart Disease and Stroke Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, brain health, complications of pregnancy, kidney disease, congenital heart disease, rhythm disorders, sudden cardiac arrest, subclinical atherosclerosis, coronary heart disease, cardiomyopathy, heart failure, valvular disease, venous thromboembolism, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The AHA, through its Epidemiology and Prevention Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States and globally to provide the most current information available in the annual Statistical Update with review of published literature through the year before writing. The 2025 AHA Statistical Update is the product of a full year's worth of effort in 2024 by dedicated volunteer clinicians and scientists, committed government professionals, and AHA staff members. This year's edition includes a continued focus on health equity across several key domains and enhanced global data that reflect improved methods and incorporation of ≈3000 new data sources since last year's Statistical Update.

RESULTS

Each of the chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policymakers, media professionals, clinicians, health care administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

The Relationship Between Maternal Exposure to Endocrine-Disrupting Chemicals and the Incidence of Congenital Heart Diseases: A Systematic Review and Meta-Analysis

BACKGROUND

Congenital heart diseases are among the most common birth defects, significantly impacting infant health. Recent evidence suggests that exposure to endocrine-disrupting chemicals may contribute to the incidence of congenital heart diseases. This study systematically reviews and analyzes the association between maternal endocrine-disrupting chemicals exposure and congenital heart diseases.

METHODOLOGY

This systematic review and meta-analysis followed the Cochrane Handbook and PRISMA guidelines. We included studies assessing the link between maternal exposure to various endocrine-disrupting chemicals and the incidence of congenital heart diseases without restricting the study design or exposure assessment methods. Data were extracted from four databases, including PubMed, Scopus, Web of Science, and Cochrane Library, up to June 2024. Quality assessment of observational studies was conducted using the Newcastle-Ottawa Scale. Statistical analysis was performed using RevMan software version 5.3, presenting results as odds ratios with 95% confidence intervals.

RESULTS

Fifty-nine studies were included in the meta-analysis. The pooled analysis revealed a significant association between maternal endocrine-disrupting chemical exposure and the incidence of congenital heart diseases when measured using human samples (odds ratio = 1.63, 95% confidence interval [1.35-1.97], p < 0.00001). Notably, exposure to heavy metals, polycyclic aromatic hydrocarbons, and perfluoroalkyl compounds was strongly associated with congenital heart diseases. However, non-sample-based methods showed no significant overall correlation (odds ratio = 1.08, 95% confidence interval [0.93-1.26], p = 0.30), except for housing renovation compounds, which were linked to a higher incidence of congenital heart diseases.

CONCLUSIONS

Maternal exposure to specific endocrine-disrupting chemicals, particularly heavy metals and polycyclic aromatic hydrocarbons, significantly increases the risk of congenital heart diseases. These findings underscore the need for preventive measures to reduce endocrine-disrupting chemicals exposure during pregnancy and further research to elucidate the underlying mechanisms.

Genetic Insights into Congenital Cardiac Septal Defects-A Narrative Review

Congenital heart diseases (CHDs) are a group of complex diseases characterized by structural and functional malformations during development in the human heart; they represent an important problem for public health worldwide. Within these malformations, septal defects such as ventricular (VSD) and atrial septal defects (ASD) are the most common forms of CHDs. Studies have reported that CHDs are the result of genetic and environmental factors. Here, we review and summarize the role of genetics involved in cardiogenesis and congenital cardiac septal defects. Moreover, treatment regarding these congenital cardiac septal defects is also addressed.

A spatiotemporal transcriptomic atlas of mouse placentation

The placenta, a temporary but essential organ for gestational support, undergoes intricate morphological and functional transformations throughout gestation. However, the spatiotemporal patterns of gene expression underlying placentation remain poorly understood. Utilizing Stereo-seq, we constructed a Mouse Placentation Spatiotemporal Transcriptomic Atlas (MPSTA) spanning from embryonic day (E) 7.5 to E14.5, which includes the transcriptomes of large trophoblast cells that were not captured in previous single-cell atlases. We defined four distinct strata of the ectoplacental cone, an early heterogeneous trophectoderm structure, and elucidated the spatial trajectory of trophoblast differentiation during early postimplantation stages before E9.5. Focusing on the labyrinth region, the interface of nutrient exchange in the mouse placenta, our spatiotemporal ligand-receptor interaction analysis unveiled pivotal modulators essential for trophoblast development and placental angiogenesis. We also found that paternally expressed genes are exclusively enriched in the placenta rather than in the decidual regions, including a cluster of genes enriched in endothelial cells that may function in placental angiogenesis. At the invasion front, we identified interface-specific transcription factor regulons, such as Atf3, Jun, Junb, Stat6, Mxd1, Maff, Fos, and Irf7, involved in gestational maintenance. Additionally, we revealed that maternal high-fat diet exposure preferentially affects this interface, exacerbating inflammatory responses and disrupting angiogenic homeostasis. Collectively, our findings furnish a comprehensive, spatially resolved atlas that offers valuable insights and benchmarks for future explorations into placental morphogenesis and pathology.

Feto-placental and coronary endothelial genes implicated in miscarriage, congenital heart disease and stillbirth, a systematic review and meta-analysis

The first trimester placenta is very rarely investigated for placental vascular formation in developmental or diseased contexts. Defects in placental formation can cause heart defects in the fetus, and vice versa. Determining the causality is therefore difficult as both organs develop concurrently and express many of the same genes. Here, we performed a systematic review to determine feto-placental and coronary endothelial genes implicated in miscarriages, stillbirth and congenital heart defects (CHD) from human genome wide screening studies. 4 single cell RNAseq datasets from human first/early second trimester cardiac and placental samples were queried to generate a list of 1187 endothelial genes. This broad list was cross-referenced with genes implicated in the pregnancy disorders above. 39 papers reported feto-placental and cardiac coronary endothelial genes, totalling 612 variants. Vascular gene variants were attributed to the incidence of miscarriage (8 %), CHD (4 %) and stillbirth (3 %). The most common genes for CHD (NOTCH, DST, FBN1, JAG1, CHD4), miscarriage (COL1A1, HERC1), and stillbirth (AKAP9, MYLK), were involved in blood vessel and cardiac valve formation, with roles in endothelial differentiation, angiogenesis, extracellular matrix signaling, growth factor binding and cell adhesion. NOTCH1, AKAP12, CHD4, LAMC1 and SOS1 showed greater relative risk ratios with CHD. Many of the vascular genes identified were expressed highly in both placental and heart EC populations. Both feto-placental and cardiac vascular genes are likely to result in poor endothelial cell development and function during human pregnancy that leads to higher risk of miscarriage, congenital heart disease and stillbirth.

Impact of MTHFR Gene Polymorphisms C677T and A1298C on Congenital Atrial Septal Defect Risk in an Iranian Cohort

Background

Congenital heart defects (CHD) are recognized as the most common heart abnormalities amongst newborns and children, and atrial septal defect (ASD) is recognized as one of the most frequent forms of CHD. Prior studies indicated that the methylenetetrahydrofolate reductase (MTHFR) gene contributes to the etiology of CHD. Therefore, we designed a case-control study to assess the possible role of the MTHFR gene, specifically the C677T (rs1801133) and A1298C (rs1801131) polymorphisms within the Iranian ASD population sample.

Methods

A total of 166 subjects (81 children diagnosed with ASD and 85 control participants) were enrolled in this research. Samples genotyped for MTHFR rs1801133 and rs1801131 polymorphisms using the PCR-RFLP and ARMS-PCR approaches.

Results

Our results indicated that rs1801131 variant reduced the risk of ASD in codominant (OR [95%CI]: 0.41[0.21-0.83], P=0.012), dominant (OR[95%CI]: 0.48 [0.25-0.93], p=0.028) and overdominant (OR[95%CI]: 0.44 [0.23-0.81], P=0.009) models. Moreover, rs1801133 variant increased the risk of ASD in codominant (OR[95%CI]: 2.68[1.39-5.16], P = 0.003), dominant (OR [95% CI]: 2.72 [1.43-5.14], P = 0.002), overdominant (OR [95% CI]: 2.50 [1.31-4.78], P = 0.005), and allelic (OR [95% CI]: 2.16 [1.27-3.69], P = 0.004) models.

Conclusions

Our findings suggest that MTHFR rs1801133 and rs1801131 variants may potentially affect the onset of ASD.

FLT4 causes developmental disorders of the cardiovascular and lymphovascular systems via pleiotropic molecular mechanisms

AIMS

Rare, deleterious genetic variants in FLT4 are associated with Tetralogy of Fallot (TOF), the most common cyanotic congenital heart disease. The distinct genetic variants in FLT4 are also an established cause of Milroy disease, the most prevalent form of primary hereditary lymphoedema. The phenotypic features of these two conditions are non-overlapping, implying pleiotropic cellular mechanisms during development.

METHODS AND RESULTS

In this study, we show that FLT4 variants identified in patients with TOF, when expressed in primary human endothelial cells, cause aggregation of FLT4 protein in the perinuclear endoplasmic reticulum, activating proteostatic and metabolic signalling, whereas lymphoedema-associated FLT4 variants and wild-type (WT) FLT4 do not. FLT4 TOF variants display characteristic gene expression profiles in key developmental signalling pathways, revealing a role for FLT4 in cardiogenesis distinct from its role in lymphatic development. Inhibition of proteostatic signalling abrogates these effects, identifying potential avenues for therapeutic intervention. Depletion of flt4 in zebrafish caused cardiac phenotypes of reduced heart size and altered heart looping. These phenotypes were rescued with coinjection of WT human FLT4 mRNA, but incompletely or not at all by mRNA harbouring FLT4 TOF variants.

CONCLUSION

Taken together, we identify a pathogenic mechanism for FLT4 variants predisposing to TOF that is distinct from the known dominant negative mechanism of Milroy-causative variants. FLT4 variants give rise to conditions of the two circulatory subdivisions of the vascular system via distinct developmental pleiotropic molecular mechanisms.

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.

The Kids Heart BioBank: supporting 20 years of patient care and research into CHD

INTRODUCTION

The cause of most CHD is unknown and considered complex, implicating genetic and environmental factors in disease causation. The Kids Heart BioBank was established in 2003 to accelerate genetic investigations into CHD.

METHODS

Recruitment includes patients undergoing interventions for CHD at The Children's Hospital at Westmead. Informed consent is obtained from parents/guardians, and blood is collected at the time of cardiac intervention from which DNA is extracted and stored. Associated detailed clinical information and a family history are stored in the purpose-designed database.

RESULTS

To date, the Kids Heart BioBank contains biospecimens and associated clinical information from over 4,900 patients with CHD and their families. Two-thirds (64.1%) of probands have been included in research studies with 28.9% of participants who underwent genomic sequencing receiving a molecular diagnosis with direct clinical utility. The value of this resource to patients and families is highlighted by the high consent rate (94.6%) and the low withdrawal of consent rate (0.4%). The Kids Heart BioBank has supported many large national and international collaborations and contributed significantly to CHD research.

CONCLUSIONS

The Kids Heart BioBank is an invaluable resource and, together with other similar resources, the resulting research has paved the way for clinical genetic testing options for CHD patients, previously not possible. With research in the field moving away from diagnosing monogenic disease, the Kids Heart BioBank is ideally placed to support the next chapter of research efforts into complex disease mechanisms, requiring large patient cohorts with detailed phenotypic information.

Comprehensive summary: the role of PBX1 in development and cancers

PBX1 is a transcription factor that can promote the occurrence of various tumors and play a reg-ulatory role in tumor growth, metastasis, invasion, and drug resistance. Furthermore, a variant generated by fusion of E2A and PBX1, E2A-PBX1, has been found in 25% of patients with childhood acute lymphoblastic leukemia. Thus, PBX1 is a potential therapeutic target for many cancers. Here, we describe the structure of PBX1 and E2A-PBX1 as well as the molecular mecha-nisms whereby these proteins promote tumorigenesis to provide future research directions for developing new treatments. We show that PBX1 and E2A-PBX1 induce the development of highly malignant and difficult-to-treat solid and blood tumors. The development of specific drugs against their targets may be a good therapeutic strategy for PBX1-related cancers. Furthermore, we strongly recommend E2A-PBX1 as one of the genes for prenatal screening to reduce the incidence of childhood hematological malignancies.

Clinical Decision Analysis of Genetic Evaluation and Testing in 1013 Intensive Care Unit Infants with Congenital Heart Defects Supports Universal Genetic Testing

Extracardiac anomalies (ECAs) are strong predictors of genetic disorders in infants with congenital heart disease (CHD), but there are no prior studies assessing performance of ECA status as a screen for genetic diagnoses in CHD patients. This retrospective cohort study assessed this in our comprehensive inpatient CHD genetics service focusing on neonates and infants admitted to the intensive care unit (ICU). The performance and diagnostic utility of using ECA status to screen for genetic disorders was assessed using decision curve analysis, a statistical tool to assess clinical utility, determining the threshold of phenotypic screening by ECA versus a Test-All approach. Over 24% of infants had genetic diagnoses identified (n = 244/1013), and ECA-positive status indicated a 4-fold increased risk of having a genetic disorder. However, ECA status had low-moderate screening performance based on predictive summary index, a compositive measure of positive and negative predictive values. For those with genetic diagnoses, nearly one-third (32%, 78/244) were ECA-negative but had cytogenetic and/or monogenic disorders identified by genetic testing. Thus, if the presence of multiple congenital anomalies is the phenotypic driver to initiate genetic testing, 13.4% (78/580) of infants with isolated CHD with identifiable genetic causes will be missed. Given the prevalence of genetic disorders and limited screening performance of ECA status, this analysis supports genetic testing in all CHD infants in intensive care settings rather than screening based on ECA.

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.

Genetic determinants of blood pressure and heart rate identified through ENU-induced mutagenesis with automated meiotic mapping

We used N-ethyl-N-nitrosurea-induced germline mutagenesis combined with automated meiotic mapping to identify specific systolic blood pressure (SBP) and heart rate (HR) determinant loci. We analyzed 43,627 third-generation (G3) mice from 841 pedigrees to assess the effects of 45,378 variant alleles within 15,760 genes, in both heterozygous and homozygous states. We comprehensively tested 23% of all protein-encoding autosomal genes and found 87 SBP and 144 HR (with 7 affecting both) candidates exhibiting detectable hypomorphic characteristics. Unexpectedly, only 18 of the 87 SBP genes were previously known, while 26 of the 144 genes linked to HR were previously identified. Furthermore, we confirmed the influence of two genes on SBP regulation and three genes on HR control through reverse genetics. This underscores the importance of our research in uncovering genes associated with these critical cardiovascular risk factors and illustrate the effectiveness of germline mutagenesis for defining key determinants of polygenic phenotypes that must be studied in an intact organism.

2024 Heart Disease and Stroke Statistics: A Report of US and Global Data From the American Heart Association

BACKGROUND

The American Heart Association (AHA), in conjunction with the National Institutes of Health, annually reports the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, nutrition, sleep, and obesity) and health factors (cholesterol, blood pressure, glucose control, and metabolic syndrome) that contribute to cardiovascular health. The AHA Heart Disease and Stroke Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, brain health, complications of pregnancy, kidney disease, congenital heart disease, rhythm disorders, sudden cardiac arrest, subclinical atherosclerosis, coronary heart disease, cardiomyopathy, heart failure, valvular disease, venous thromboembolism, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The AHA, through its Epidemiology and Prevention Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States and globally to provide the most current information available in the annual Statistical Update with review of published literature through the year before writing. The 2024 AHA Statistical Update is the product of a full year's worth of effort in 2023 by dedicated volunteer clinicians and scientists, committed government professionals, and AHA staff members. The AHA strives to further understand and help heal health problems inflicted by structural racism, a public health crisis that can significantly damage physical and mental health and perpetuate disparities in access to health care, education, income, housing, and several other factors vital to healthy lives. This year's edition includes additional global data, as well as data on the monitoring and benefits of cardiovascular health in the population, with an enhanced focus on health equity across several key domains.

RESULTS

Each of the chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policymakers, media professionals, clinicians, health care administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

Human Genetics of Ventricular Septal Defect

Ventricular septal defects (VSDs) are recognized as one of the commonest congenital heart diseases (CHD), accounting for up to 40% of all cardiac malformations, and occur as isolated CHDs as well as together with other cardiac and extracardiac congenital malformations in individual patients and families. The genetic etiology of VSD is complex and extraordinarily heterogeneous. Chromosomal abnormalities such as aneuploidy and structural variations as well as rare point mutations in various genes have been reported to be associated with this cardiac defect. This includes both well-defined syndromes with known genetic cause (e.g., DiGeorge syndrome and Holt-Oram syndrome) and so far undefined syndromic forms characterized by unspecific symptoms. Mutations in genes encoding cardiac transcription factors (e.g., NKX2-5 and GATA4) and signaling molecules (e.g., CFC1) have been most frequently found in VSD cases. Moreover, new high-resolution methods such as comparative genomic hybridization enabled the discovery of a high number of different copy number variations, leading to gain or loss of chromosomal regions often containing multiple genes, in patients with VSD. In this chapter, we will describe the broad genetic heterogeneity observed in VSD patients considering recent advances in this field.

Noncardiac anomalies in children with congenital heart disease

Introduction

Noncardiac anomalies (NCAs) in patients with congenital heart defects (CHDs) are crucial for perioperative management and etiology studies. This study aimed to investigate NCAs in Chinese children with CHDs.

Methods

Medical records for CHD-diagnosed children hospitalized from 1 January 2015 to 31 December 2019 were collected and subjected to retrospective analyses to excavate potential association rules between CHDs and noncardiac malformations.

Results

A total of 3,788 CHD patients were included in this study. The main phenotypes of CHD were Ventricular Septal Defect (VSD, 33.69%), Atrial Septal Defect (ASD, 12.72%), and Tetralogy of Fallot (TOF, 5.54%). A total of 887 (23.42%) cases showed noncardiac anomalies, which were mainly associated with the central nervous system (34.61%), nose/ear/mandibular/face (19.39%), genitourinary system (15.78%), and musculoskeletal system (15.56%). Compared to other CHD subtypes, septal defects had a lower percentage of associated NCAs (P = 3.7 × 10-9) while AVSD had a higher percentage (P = 0.0018).

Disscussion

NCAs are prevalent among CHD-diagnosed children in China, and the spectrums of NCAs in different CHD subcategories were different.

Repurposing Normal Chromosomal Microarray Data to Harbor Genetic Insights into Congenital Heart Disease

About 15% of congenital heart disease (CHD) patients have a known pathogenic copy number variant. The majority of their chromosomal microarray (CMA) tests are deemed normal. Diagnostic interpretation typically ignores microdeletions smaller than 100 kb. We hypothesized that unreported microdeletions are enriched for CHD genes. We analyzed "normal" CMAs of 1762 patients who were evaluated at a pediatric referral center, of which 319 (18%) had CHD. Using CMAs from monozygotic twins or replicates from the same individual, we established a size threshold based on probe count for the reproducible detection of small microdeletions. Genes in the microdeletions were sequentially filtered by their nominal association with a CHD diagnosis, the expression level in the fetal heart, and the deleteriousness of a loss-of-function mutation. The subsequent enrichment for CHD genes was assessed using the presence of known or potentially novel genes implicated by a large whole-exome sequencing study of CHD. The unreported microdeletions were modestly enriched for both known CHD genes and those of unknown significance identified using their de novo mutation in CHD patients. Our results show that readily available "normal" CMA data can be a fruitful resource for genetic discovery and that smaller deletions should receive more attention in clinical evaluation.

Analysis of pathogenic variants in 605 Chinese children with non-syndromic cardiac conotruncal defects based on targeted sequencing

OBJECTIVE

Deleterious genetic variants comprise one cause of cardiac conotruncal defects (CTDs). Genes associated with CTDs are gradually being identified. In the present study, we aimed to explore the profile of genetic variants of CTD-associated genes in Chinese patients with non-syndromic CTDs.

METHODS

Thirty-nine CTD-related genes were selected after reviewing published articles in NCBI, HGMD, OMIM, and HPO. In total, 605 patients with non-syndromic CTDs and 300 healthy controls, all of Han ethnicity, were recruited. High-throughput targeted sequencing was used to detect genetic variants in the protein-coding regions of genes. We performed rigorous variant-level filtrations to identify potentially damaging variants (Dvars) using prediction programs including CADD, SIFT, PolyPhen-2, and MutationTaster.

RESULT

Dvars were detected in 66.7% (26/39) of the targeted CTD-associated genes. In total, 11.07% (67/605) of patients with non-syndromic CTDs were found to carry one or more Dvars in targeted CTD-associated genes. Dvars in FOXH1, TBX2, NFATC1, FOXC2, and FOXC1 were common in the CTD cohort (1.5% [9/605], 1.2% [7/605], 1.2% [7/605], 1% [6/605], and 0.5% [3/605], respectively).

CONCLUSION

Targeted exon sequencing is a cost-effective approach for the genetic diagnosis of CTDs. Our findings contribute to an understanding of the genetic architecture of non-syndromic CTDs.

CRISPR-based knockout and base editing confirm the role of MYRF in heart development and congenital heart disease

High-throughput DNA sequencing studies increasingly associate DNA variants with congenital heart disease (CHD). However, functional modeling is a crucial prerequisite for translating genomic data into clinical care. We used CRISPR-Cas9-mediated targeting of 12 candidate genes in the vertebrate model medaka (Oryzias latipes), five of which displayed a novel cardiovascular phenotype spectrum in F0 (crispants): mapre2, smg7, cdc42bpab, ankrd11 and myrf, encoding a transcription factor recently linked to cardiac-urogenital syndrome. Our myrf mutant line showed particularly prominent embryonic cardiac defects recapitulating phenotypes of pediatric patients, including hypoplastic ventricle. Mimicking human mutations, we edited three sites to generate specific myrf single-nucleotide variants via cytosine and adenine base editors. The Glu749Lys missense mutation in the conserved intramolecular chaperon autocleavage domain fully recapitulated the characteristic myrf mutant phenotype with high penetrance, underlining the crucial function of this protein domain. The efficiency and scalability of base editing to model specific point mutations accelerate gene validation studies and the generation of human-relevant disease models.

The Roles of Histone Lysine Methyltransferases in Heart Development and Disease

Epigenetic marks regulate the transcriptomic landscape by facilitating the structural packing and unwinding of the genome, which is tightly folded inside the nucleus. Lysine-specific histone methylation is one such mark. It plays crucial roles during development, including in cell fate decisions, in tissue patterning, and in regulating cellular metabolic processes. It has also been associated with varying human developmental disorders. Heart disease has been linked to deregulated histone lysine methylation, and lysine-specific methyltransferases (KMTs) are overrepresented, i.e., more numerous than expected by chance, among the genes with variants associated with congenital heart disease. This review outlines the available evidence to support a role for individual KMTs in heart development and/or disease, including genetic associations in patients and supporting cell culture and animal model studies. It concludes with new advances in the field and new opportunities for treatment.

Associations Between the Lead Level in Maternal Blood and Umbilical Cord Blood and Congenital Heart Diseases in Offspring

The incidence of congenital heart diseases (CHDs) shows an increasing trend and results in large health burdens in China. However, there have been inconsistent results of the relationship between lead (Pb) level and risk of CHDs. We performed a pair-matched case-control study and included 97 cases and 194 controls to investigate the association between pregnancy Pb exposure and the risk of CHDs in a birth cohort study conducted in Lanzhou, China. The results showed that compared to the lowest Pb tertile, both highest tertile levels of maternal blood and umbilical cord blood Pb were associated with an increased risk of CHDs. The similar significant results were found in cases with isolated CHDs. Compared to both lowest tertiles of Pb level in maternal blood and umbilical cord blood, the highest tertile was associated with an increased risk of CHDs, especially for isolated CHDs. Overall, our study suggests a significant association between pregnancy Pb exposure and risk of CHDs, especially for isolated CHDs. Future studies are needed to elucidate the underlying mechanism.

The angiopoietin receptor Tie2 is atheroprotective in arterial endothelium

Leukocytes and resident cells in the arterial wall contribute to atherosclerosis, especially at sites of disturbed blood flow. Expression of endothelial Tie1 receptor tyrosine kinase is enhanced at these sites, and attenuation of its expression reduces atherosclerotic burden and decreases inflammation. However, Tie2 tyrosine kinase function in atherosclerosis is unknown. Here we provide genetic evidence from humans and from an atherosclerotic mouse model to show that TIE2 is associated with protection from coronary artery disease. We show that deletion of Tie2, or both Tie2 and Tie1, in the arterial endothelium promotes atherosclerosis by increasing Foxo1 nuclear localization, endothelial adhesion molecule expression and accumulation of immune cells. We also show that Tie2 is expressed in a subset of aortic fibroblasts, and its silencing in these cells increases expression of inflammation-related genes. Our findings indicate that unlike Tie1, the Tie2 receptor functions as the dominant endothelial angiopoietin receptor that protects from atherosclerosis.

Heart Disease and Stroke Statistics-2023 Update: A Report From the American Heart Association

BACKGROUND

The American Heart Association, in conjunction with the National Institutes of Health, annually reports the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, diet, and weight) and health factors (cholesterol, blood pressure, and glucose control) that contribute to cardiovascular health. The Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, congenital heart disease, rhythm disorders, subclinical atherosclerosis, coronary heart disease, heart failure, valvular disease, venous disease, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The American Heart Association, through its Epidemiology and Prevention Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States to provide the most current information available in the annual Statistical Update with review of published literature through the year before writing. The 2023 Statistical Update is the product of a full year's worth of effort in 2022 by dedicated volunteer clinicians and scientists, committed government professionals, and American Heart Association staff members. The American Heart Association strives to further understand and help heal health problems inflicted by structural racism, a public health crisis that can significantly damage physical and mental health and perpetuate disparities in access to health care, education, income, housing, and several other factors vital to healthy lives. This year's edition includes additional COVID-19 (coronavirus disease 2019) publications, as well as data on the monitoring and benefits of cardiovascular health in the population, with an enhanced focus on health equity across several key domains.

RESULTS

Each of the chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policymakers, media professionals, clinicians, health care administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

Evaluating High-Confidence Genes in Conotruncal Cardiac Defects by Gene Burden Analyses

Background In nonsyndromic conotruncal cardiac defects, the use of next-generation sequencing for clinical diagnosis is increasingly adopted, but gene-disease associations in research are only partially translated to diagnostic panels, suggesting a need for evidence-based consensus. Methods and Results In an exome data set of 245 patients with conotruncal cardiac defects, we performed burden analysis on a high-confidence congenital heart disease gene list (n=132) with rare (<0.01%) and ultrarare (absent in the Genome Aggregation Database) protein-altering variants. Overall, we confirmed an excess of rare variants compared with ethnicity-matched controls and identified 2 known genes (GATA6, NOTCH1) and 4 candidate genes supported by the literature (ANKRD11, DOCK6, NPHP4, and STRA6). Ultrarare variant analysis was performed in combination with 3 other published studies (n=1451) and identified 3 genes (FLT4, NOTCH1, TBX1) to be significant, whereas a subgroup analysis involving 391 Chinese subjects identified only GATA6 as significant. Conclusions We suggest that these significant genes in our rare and ultrarare burden analyses warrant prioritization for clinical testing implied for rare inherited and de novo variants. Additionally, associations on ClinVar for these genes were predominantly variants of uncertain significance. Therefore, a more stringent assessment of gene-disease associations in a larger and ethnically diverse cohort is required to be prudent for future curation of conotruncal cardiac defect genes.

Drawing a line between histone demethylase KDM5A and KDM5B: their roles in development and tumorigenesis

Distinct epigenetic modifiers ensure coordinated control over genes that govern a myriad of cellular processes. Growing evidence shows that dynamic regulation of histone methylation is critical for almost all stages of development. Notably, the KDM5 subfamily of histone lysine-specific demethylases plays essential roles in the proper development and differentiation of tissues, and aberrant regulation of KDM5 proteins during development can lead to chronic developmental defects and even cancer. In this review, we adopt a unique perspective regarding the context-dependent roles of KDM5A and KDM5B in development and tumorigenesis. It is well known that these two proteins show a high degree of sequence homology, with overlapping functions. However, we provide deeper insights into their substrate specificity and distinctive function in gene regulation that at times divert from each other. We also highlight both the possibility of targeting KDM5A and KDM5B to improve cancer treatment and the limitations that must be overcome to increase the efficacy of current drugs.

A novel stop-gain pathogenic variant in FLT4 and a nonsynonymous pathogenic variant in PTPN11 associated with congenital heart defects

BACKGROUND

Congenital heart defects (CHDs) are the most common congenital malformations, including structural malformations in the heart and great vessels. CHD complications such as low birth weight, prematurity, pregnancy termination, mortality, and morbidity depend on the type of defect.

METHODS

In the present research, genetic analyses via whole-exome sequencing (WES) was performed on 3 unrelated pedigrees with CHDs. The candidate variants were confirmed, segregated by PCR-based Sanger sequencing, and evaluated by bioinformatics analysis.

RESULTS

A novel stop-gain c.C244T:p.R82X variant in the FLT4 gene, as well as a nonsynonymous c.C1403T:p.T468M variant in the PTPN11 gene, was reported by WES. FLT4 encodes a receptor tyrosine kinase involved in lymphatic development and is known as vascular endothelial growth factor 3.

CONCLUSIONS

We are the first to report a novel c.C244T variant in the FLT4 gene associated with CHDs. Using WES, we also identified a nonsynonymous variant affecting protein-tyrosine phosphatase, the non-receptor type 11 (PTPN11) gene. The clinical implementation of WES can determine gene variants in diseases with high genetic and phenotypic heterogeneity like CHDs.

Maternal exposure to heavy metals and risk for severe congenital heart defects in offspring

BACKGROUND

Congenital heart defects (CHDs) are the most common congenital malformations with a complex etiology, and environmental factors play an important role. Large epidemiology studies on prenatal exposure to selected heavy metals and their association with risk for CHDs are scarce and joint effects are not well understood.

OBJECTIVES

To examine the association between prenatal exposure to selected heavy metals and risk for CHDs.

METHODS

Inductively coupled plasma mass spectrometry (ICP-MS) was used to determine the maternal plasma concentrations of arsenic, cadmium, mercury, lead, and manganese were in 303 CHD cases and 303 healthy controls that were recruited in eight hospitals in China. Generalized linear mixed model (GLMM) and Bayesian kernel machine regression (BKMR) were fitted to evaluate the individual and joint effects of metal concentrations on CHDs.

RESULTS

In GLMM, two metals were each significantly associated with an increased risk for CHDs [adjusted odds ratio (95% confidence interval): mercury, 2.88 (1.22-6.77); lead, 2.74 (1.00-7.57)]. In BKMR, CHD risk increased with mixture levels of the five metals when their concentrations were at the 40th percentile or higher, compared to when all metals were below their 35th percentile, and mercury was the major metal that contributed to the mixture effect. The interaction between mercury and lead was observed in BKMR.

CONCLUSIONS

Using metal concentrations in maternal plasma obtained during the second or third trimester as exposure markers, we found that the risk of CHDs increased with the levels of the mixtures of As, Cd, Hg, Pb, and Mn, with Hg being the most important contributor to the mixture effect.

Effect of Maternal Antidepressant Use During the Pre-pregnancy/Early Pregnancy Period on Congenital Heart Disease: A Prospective Cohort Study in Central China

Background

With the increase in maternal antidepressant prescribing before/during pregnancy, concerns about the safety of antidepressants have come into focus. The purpose of this study was to explore the association between maternal antidepressant use before pregnancy/in early pregnancy and the risk of congenital heart disease (CHD) in children, and to provide a scientific basis for clinical safety of antidepressant use.

Methods

The prospective cohort study ultimately included 34,104 singleton pregnancies. Modified Poisson regression model with robust error variances was used to evaluate RRs and 95% confidence intervals (CIs) for the risk of CHD in offspring exposed to maternal antidepressant in the 3 months before pregnancy and early pregnancy. In addition, sensitivity analysis was further performed to explore the robustness of the results.

Results

In this study, the maternal antidepressant exposure rate was 2.83% in the 3 months before pregnancy, 2.42% in early pregnancy, and the incidence of CHD was 8.973 per 1,000 live births. We found that maternal antidepressant use in the 3 months before pregnancy and early pregnancy were all associated with an increased risk of CHD, ~2.54 times and 2.87 times, respectively, of non-use of antidepressants after adjusting for potential confounders. This association was also found in CHD specific phenotypic analysis. Of these, offspring whose mothers were exposed to antidepressants in the 3 months before pregnancy had the highest risk of transposition of the great arteries (aOR = 5.50, 95% CI: 1.91–15.88). The offspring of mothers exposed to antidepressants in early pregnancy had the highest risk of developing ventricular septal defect (aOR = 4.80, 95% CI: 2.50–9.24). Sensitivity analysis verified the stability of the results.

Conclusions

Maternal antidepressant use in the 3 months before pregnancy and early pregnancy were all associated with an increased risk of CHD in their offspring. In order to reduce the risk of teratogenesis, we recommend that pregnant women prepare for pregnancy after their condition improves or receive the minimum effective dose of medication.

Transcriptomic and ChIP-seq Integrative Analysis Identifies KDM5A-Target Genes in Cardiac Fibroblasts

Cardiac fibrosis is a common pathological feature in cardiac remodeling. This study aimed to explore the role of KDM5A in cardiac fibrosis via bioinformatics analysis. Cardiac fibroblasts (CFs) were harvested and cultured from 10 dilated cardiomyopathy (DCM) patients who underwent heart transplantation. Western blotting was applied to verify that KDM5A is regulated by angiotensin II (Ang II) via the PI3k/AKT signaling pathway. The differentially expressed genes (DEGs) were analyzed by transcriptomics. ChIP-seq and ChIP-qPCR were used to identify the genes bound by KDM5A. In integrative analysis, weighted gene coexpression network analysis (WGCNA) was performed to identify highly relevant gene modules. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed for the key genes in modules. The STRING database, Cytoscape, and MCODE were applied to construct the protein–protein interaction (PPI) network and screen hub genes. To verify the expression of DEGs regulated by KDM5A, Western blotting and immunofluorescence were performed in myocardial tissue samples. Immunofluorescence verified the vimentin positivity of CFs. Ang II upregulated the expression of KDM5A in CFs via the PI3K/AKT signaling pathway. GO analysis of DEGs indicated that regulation of vasoconstriction, extracellular region, and calcium ion binding were enriched when KDM5A interfered with CPI or Ang II. KEGG analysis of the DEGs revealed the involvement of ECM-receptor interaction, focal adhesion, PI3K-Akt signaling pathway, cell adhesion, and arrhythmogenic right ventricular cardiomyopathy pathways. Three hub genes (IGF1, MYH11, and TGFB3) were identified via four different algorithms. Subsequent verification in patient samples demonstrated that the hub genes, which were regulated by KDM5A, were downregulated in DCM samples. KDM5A is a key regulator in the progression of cardiac fibrosis. In this successful integrative analysis, IGF1, MYH11, and TGFB3 were determined to be coordinately expressed to participate in cardiac fibrosis.

TBX5 variant with the novel phenotype of mixed‑type total anomalous pulmonary venous return in Holt‑Oram Syndrome and variable intrafamilial heart defects

Variants in T‑box transcription factor 5 (TBX5) can result in a wide phenotypic spectrum, specifically in the heart and the limbs. TBX5 has been implicated in causing non‑syndromic cardiac defects and Holt‑Oram syndrome (HOS). The present study investigated the underlying molecular etiology of a family with heterogeneous heart defects. The proband had mixed‑type total anomalous pulmonary venous return (mixed‑type TAPVR), whereas her mother had an atrial septal defect. Genetic testing through trio‑based whole‑exome sequencing was used to reveal the molecular etiology. A nonsense variant was identified in TBX5 (c.577G>T; p.Gly193*) initially showing co‑segregation with a presumably non‑syndromic presentation of congenital heart disease. Subsequent genetic investigations and more complete phenotyping led to the correct diagnosis of HOS, documenting the novel association of mixed‑type TAPVR with HOS. Finally, protein modeling of the mutant TBX5 protein that harbored this pathogenic nonsense variant (p.Gly193*) revealed a substantial drop in the quantity of non‑covalent bonds. The decrease in the number of non‑covalent bonds suggested that the resultant mutant dimer was less stable compared with the wild‑type protein, consequently affecting the protein's ability to bind DNA. The present findings extended the phenotypic cardiac defects associated with HOS; to the best of our knowledge, this is the first association of mixed‑type TAPVR with TBX5. Prior to the current analysis, the molecular association of TAPVR with HOS had never been documented; hence, this is the first genetic investigation to report the association between TAPVR and HOS. Furthermore, it was demonstrated that the null‑variants reported in the T‑box domain of TBX5 were associated with a wide range of cardiac and/or skeletal anomalies on both the inter‑and intrafamilial levels. In conclusion, genetic testing was highlighted as a potentially powerful approach in the prognostication of the proper diagnosis.

Comparison of Blood Lead Concentrations in Mothers of Children with Congenital Heart Disease and Mothers of Healthy Children

Congenital heart disease (CHD) is the most prevalent congenital defect that causes several problems for patients and their families and medical specialists. It is important to investigate CHD risk factors due to their significantly destructive load on society. This study aims to determine the association between maternal lead exposure and conceiving a child with CHD. This case-control study was performed on a total of 246 mothers in the pediatric clinic of Vali-e-Asr Hospital in Birjand, Iran. One hundred forty-six mothers with CHD children were defined as the case group, and 100 age-matched mothers with healthy children were considered the control group. All the mothers were between 20 and 40 years old, and their children were under the age of 6 months. Demographic data was collected from mothers using a well-designed questionnaire. In addition, all mothers were referred to the laboratory for measuring blood lead concentrations. The mean blood lead concentration (BLC) of mothers in the group of children with heart problems was 4.11 ± 10.02 with a median of 2.50 μg/dL and in the control group was 2.66 ± 2.06 with a median of 2.30 μg/dL. The Mann-Whitney test results showed that mothers' lead concentration in the group of children with heart problems was significantly higher than the control group (z = 2.13, p = 0.03). The chi-square test results showed that lead concentrations in the two groups were significantly different from each other (χ² = 9.11, p = 0.01). The results of our study showed that mothers of children with CHD had higher blood concentrations than mothers of healthy children.

Diagnostic yield of whole exome data in fetuses aborted for conotruncal malformations

OBJECTIVE

We investigated a custom congenital heart disease (CHD) geneset to assess the diagnostic value of whole-exome sequencing (WES) in karyotype- and copy number variation (CNV)-negative aborted fetuses with conotruncal defects (CTD), and to explore the impact of postnatal phenotyping on genetic diagnosis.

METHODS

We sequentially analyzed CNV-seq and WES data from 47 CTD fetuses detected by prenatal ultrasonography. Fetuses with either a confirmed aneuploidy or pathogenic CNV were excluded from the WES analyses, which were performed following the American College of Medical Genetics and Genomics recommendations and a custom CHD-geneset. Imaging and autopsy were applied to obtain postnatal phenotypic information about aborted fetuses.

RESULTS

CNV-seq identified aneuploidy in 7/47 cases while 13/47 fetuses were CNV-positive. Eighty-five rare deleterious variants in 61 genes (from custom geneset) were identified by WES in the remaining fetuses. Of these, five (likely) pathogenic variants (LPV/PV) were identified in five fetuses, revealing a 10.6% incremental diagnostic yield. Furthermore, RERE:c.2461_2472delGGGATGTGGCGA was reclassified as LPV based on postnatal phenotypic data.

CONCLUSION

We have developed and defined a CHD gene panel that can be utilized in a subset of fetuses with CTDs. We demonstrate the utility of incorporating both prenatal and postnatal phenotypic information may facilitate WES diagnostics. This article is protected by copyright. All rights reserved.

Benchmarking the Effectiveness and Accuracy of Multiple Mitochondrial DNA Variant Callers: Practical Implications for Clinical Application

Mitochondrial DNA (mtDNA) mutations contribute to human disease across a range of severity, from rare, highly penetrant mutations causal for monogenic disorders to mutations with milder contributions to phenotypes. mtDNA variation can exist in all copies of mtDNA or in a percentage of mtDNA copies and can be detected with levels as low as 1%. The large number of copies of mtDNA and the possibility of multiple alternative alleles at the same DNA nucleotide position make the task of identifying allelic variation in mtDNA very challenging. In recent years, specialized variant calling algorithms have been developed that are tailored to identify mtDNA variation from whole-genome sequencing (WGS) data. However, very few studies have systematically evaluated and compared these methods for the detection of both homoplasmy and heteroplasmy. A publicly available synthetic gold standard dataset was used to assess four mtDNA variant callers (Mutserve, mitoCaller, MitoSeek, and MToolBox), and the commonly used Genome Analysis Toolkit “best practices” pipeline, which is included in most current WGS pipelines. We also used WGS data from 126 trios and calculated the percentage of maternally inherited variants as a metric of calling accuracy, especially for homoplasmic variants. We additionally compared multiple pathogenicity prediction resources for mtDNA variants. Although the accuracy of homoplasmic variant detection was high for the majority of the callers with high concordance across callers, we found a very low concordance rate between mtDNA variant callers for heteroplasmic variants ranging from 2.8% to 3.6%, for heteroplasmy thresholds of 5% and 1%. Overall, Mutserve showed the best performance using the synthetic benchmark dataset. The analysis of mtDNA pathogenicity resources also showed low concordance in prediction results. We have shown that while homoplasmic variant calling is consistent between callers, there remains a significant discrepancy in heteroplasmic variant calling. We found that resources like population frequency databases and pathogenicity predictors are now available for variant annotation but still need refinement and improvement. With its peculiarities, the mitochondria require special considerations, and we advocate that caution needs to be taken when analyzing mtDNA data from WGS data.

Heart Disease and Stroke Statistics-2022 Update: A Report From the American Heart Association

BACKGROUND

The American Heart Association, in conjunction with the National Institutes of Health, annually reports the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, diet, and weight) and health factors (cholesterol, blood pressure, and glucose control) that contribute to cardiovascular health. The Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, congenital heart disease, rhythm disorders, subclinical atherosclerosis, coronary heart disease, heart failure, valvular disease, venous disease, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The American Heart Association, through its Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States to provide the most current information available in the annual Statistical Update. The 2022 Statistical Update is the product of a full year's worth of effort by dedicated volunteer clinicians and scientists, committed government professionals, and American Heart Association staff members. This year's edition includes data on the monitoring and benefits of cardiovascular health in the population and an enhanced focus on social determinants of health, adverse pregnancy outcomes, vascular contributions to brain health, and the global burden of cardiovascular disease and healthy life expectancy.

RESULTS

Each of the chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policymakers, media professionals, clinicians, health care administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

How does the convergence of prematurity and congenital heart disease impact the developing brain?

Prematurity and congenital heart disease (CHD) are individually associated with increased risk of brain injury and adverse neurodevelopmental outcomes. Delayed brain development in newborns with CHD has been documented to begin in utero and predisposes newborns with CHD to brain injury. Little is known about the combined risks when prematurity and CHD co-occur. The purpose of this review is to highlight the unique vulnerability of preterm newborns with CHD to brain dysmaturation and brain injury, and the urgent need for prospective research.

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

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

Genetics of congenital heart disease: a narrative review of recent advances and clinical implications

Congenital heart disease (CHD) is the most common human birth defect and remains a leading cause of mortality in childhood. Although advances in clinical management have improved the survival of children with CHD, adult survivors commonly experience cardiac and non-cardiac comorbidities, which affect quality of life and prognosis. Therefore, the elucidation of genetic etiologies of CHD not only has important clinical implications for genetic counseling of patients and families but may also impact clinical outcomes by identifying at-risk patients. Recent advancements in genetic technologies, including massively parallel sequencing, have allowed for the discovery of new genetic etiologies for CHD. Although variant prioritization and interpretation of pathogenicity remain challenges in the field of CHD genomics, advances in single-cell genomics and functional genomics using cellular and animal models of CHD have the potential to provide novel insights into the underlying mechanisms of CHD and its associated morbidities. In this review, we provide an updated summary of the established genetic contributors to CHD and discuss recent advances in our understanding of the genetic architecture of CHD along with current challenges with the interpretation of genetic variation. Furthermore, we highlight the clinical implications of genetic findings to predict and potentially improve clinical outcomes in patients with CHD.

Functional characterization of a novel PBX1 de novo missense variant identified in a patient with syndromic congenital heart disease

Pre-B cell leukemia factor 1 (PBX1) is an essential developmental transcription factor, mutations in which have recently been associated with CAKUTHED syndrome, characterized by multiple congenital defects including congenital heart disease (CHD). During analysis of a whole-exome-sequenced cohort of heterogeneous CHD patients, we identified a de novo missense variant, PBX1:c.551G>C p.R184P, in a patient with tetralogy of Fallot with absent pulmonary valve and extra-cardiac phenotypes. Functional analysis of this variant by creating a CRISPR-Cas9 gene-edited mouse model revealed multiple congenital anomalies. Congenital heart defects (persistent truncus arteriosus and ventricular septal defect), hypoplastic lungs, hypoplastic/ectopic kidneys, aplastic adrenal glands and spleen, as well as atretic trachea and palate defects were observed in the homozygous mutant embryos at multiple stages of development. We also observed developmental anomalies in a proportion of heterozygous embryos, suggestive of a dominant mode of inheritance. Analysis of gene expression and protein levels revealed that although Pbx1 transcripts are higher in homozygotes, amounts of PBX1 protein are significantly decreased. Here, we have presented the first functional model of a missense PBX1 variant and provided strong evidence that p.R184P is disease-causal. Our findings also expand the phenotypic spectrum associated with pathogenic PBX1 variants in both humans and mice.

A Reassessment of Copy Number Variations in Congenital Heart Defects: Picturing the Whole Genome

Copy number variations (CNVs) can modulate phenotypes by affecting protein-coding sequences directly or through interference of gene expression. Recent studies in cancer and limb defects pinpointed the relevance of non-coding gene regulatory elements such as long non-coding RNAs (lncRNAs) and topologically associated domain (TAD)-related gene-enhancer interactions. The contribution of such non-coding elements is largely unexplored in congenital heart defects (CHD). We performed a retrospective analysis of CNVs reported in a cohort of 270 CHD patients. We reviewed the diagnostic yield of pathogenic CNVs, and performed a comprehensive reassessment of 138 CNVs of unknown significance (CNV-US), evaluating protein-coding genes, lncRNA genes, and potential interferences with TAD-related gene-enhancer interactions. Fifty-two of the 138 CNV-US may relate to CHD, revealing three candidate CHD regions, 19 candidate CHD genes, 80 lncRNA genes of interest, and six potentially CHD-related TAD interferences. Our study thus indicates a potential relevance of non-coding gene regulatory elements in CNV-related CHD pathogenesis. Shortcomings in our current knowledge on genomic variation call for continuous reporting of CNV-US in international databases, careful patient counseling, and additional functional studies to confirm these preliminary findings.

The physiological and pathological functions of VEGFR3 in cardiac and lymphatic development and related diseases

Vascular endothelial growth factor receptors (VEGFRs) are part of the evolutionarily conserved VEGF signalling pathways that regulate the development and maintenance of the body's cardiovascular and lymphovascular systems. VEGFR3, encoded by the FLT4 gene, has an indispensable and well-characterized function in development and establishment of the lymphatic system. Autosomal dominant VEGFR3 mutations, that prevent the receptor functioning as a homodimer, cause one of the major forms of hereditary primary lymphoedema; Milroy disease. Recently, we and others have shown that FLT4 variants, distinct to those observed in Milroy disease cases, predispose individuals to Tetralogy of Fallot, the most common cyanotic congenital heart disease, demonstrating a novel function for VEGFR3 in early cardiac development. Here, we examine the familiar and emerging roles of VEGFR3 in the development of both lymphovascular and cardiovascular systems, respectively, compare how distinct genetic variants in FLT4 lead to two disparate human conditions, and highlight the research still required to fully understand this multifaceted receptor.

From Stem Cells to Populations-Using hiPSC, Next-Generation Sequencing, and GWAS to Explore the Genetic and Molecular Mechanisms of Congenital Heart Defects

Congenital heart defects (CHD) are developmental malformations affecting the heart and the great vessels. Early heart development requires temporally regulated crosstalk between multiple cell types, signaling pathways, and mechanical forces of early blood flow. While both genetic and environmental factors have been recognized to be involved, identifying causal genes in non-syndromic CHD has been difficult. While variants following Mendelian inheritance have been identified by linkage analysis in a few families with multiple affected members, the inheritance pattern in most familial cases is complex, with reduced penetrance and variable expressivity. Furthermore, most non-syndromic CHD are sporadic. Improved sequencing technologies and large biobank collections have enabled genome-wide association studies (GWAS) in non-syndromic CHD. The ability to generate human to create human induced pluripotent stem cells (hiPSC) and further differentiate them to organotypic cells enables further exploration of genotype–phenotype correlations in patient-derived cells. Here we review how these technologies can be used in unraveling the genetics and molecular mechanisms of heart development.

Association analysis of maternal MTHFR gene polymorphisms and the occurrence of congenital heart disease in offspring

BACKGROUND

Although many studies showed that the risk of congenital heart disease (CHD) was closely related to genetic factors, the exact pathogenesis is still unknown. Our study aimed to comprehensively assess the association of single nucleotide polymorphisms (SNPs) of maternal MTHFR gene with risk of CHD and its three subtypes in offspring.

METHODS

A case-control study involving 569 mothers of CHD cases and 652 health controls was conducted. Thirteen SNPs were detected and analyzed.

RESULTS

Our study showed that genetic polymorphisms of maternal MTHFR gene at rs4846052 and rs1801131 were significantly associated with risk of CHD in the homozygote comparisons (TT vs. CC at rs4846052: OR = 7.62 [95%CI 2.95-19.65]; GG vs. TT at rs1801131: OR = 5.18 [95%CI 2.77-9.71]). And six haplotypes of G-C (involving rs4846048 and rs2274976), A-C (involving rs1801133 and rs4846052), G-T (involving rs1801133 and rs4846052), G-T-G (involving rs2066470, rs3737964 and rs535107), A-C-G (involving rs2066470, rs3737964 and rs535107) and G-C-G (involving rs2066470, rs3737964 and rs535107) were identified to be significantly associated with risk of CHD. Additionally, we observed that a two-locus model involving rs2066470 and rs1801131 as well as a three-locus model involving rs227497, rs1801133 and rs1801131 were significantly associated with risk of CHD in the gene-gene interaction analyses. For three subtypes including atrial septal defect, ventricular septal defect and patent ductus arteriosus, similar results were observed.

CONCLUSIONS

Our study indicated genetic polymorphisms of maternal MTHFR gene were significantly associated with risk of fetal CHD in the Chinese population. Additionally, there were significantly interactions among different SNPs on risk of CHD. However, how these SNPs affect the development of fetal heart remains unknown, and more studies in different ethnic populations and with a larger sample are required to confirm these findings.