Recurrence risks in offspring of adults with major heart defects: results from first cohort of British collaborative study

Congenital heart defects in children born after assisted reproductive technology: a CoNARTaS study

BACKGROUND AND AIMS

Children born after assisted reproductive technology (ART) have worse perinatal outcomes compared with spontaneously conceived children. This study investigates whether children conceived after ART have a higher risk of congenital heart defects (CHDs) compared with children born after spontaneous conception (SC).

METHODS

All 7 747 637 liveborn children in Denmark (1994-2014), Finland (1990-2014), Norway (1984-2015), and Sweden (1987-2015), where 171 735 children were conceived after ART, were included. National ART and medical birth registry data were cross-linked with data from other health and population registries. Outcomes were major CHDs, severe CHDs, 6 hierarchical CHD lesion groups, and 10 selected major CHDs, diagnosed prenatally or up to 1 year of age (Denmark, Finland, and Sweden) and prenatally or at birth (Norway). The association between ART and CHDs was assessed with multivariable logistic regression analysis, with adjustment for available confounders.

RESULTS

Major CHDs were detected in 3159 children born after ART (1.84%) and in 86 824 children born after SC [1.15%; adjusted odds ratio (AOR) 1.36; 95% confidence interval (CI) 1.31-1.41]. Risk was highest in multiples, regardless of conception method. Severe CHDs were detected in 594 children born after ART (0.35%) and in 19 375 children born after SC (0.26%; AOR 1.30; 95% CI 1.20-1.42). Risk was similar between ICSI and IVF and between frozen and fresh embryo transfer.

CONCLUSIONS

Assisted reproductive technology-conceived children have a higher prevalence of major CHDs, being rare, but severe conditions. The absolute risks are, however, modest and partly associated with multiple pregnancies, more prevalent in ART.

Pathogenesis and Surgical Treatment of Dextro-Transposition of the Great Arteries (D-TGA): Part II

Dextro-transposition of the great arteries (D-TGA) is the second most common cyanotic heart disease, accounting for 5-7% of all congenital heart defects (CHDs). It is characterized by ventriculoarterial (VA) connection discordance, atrioventricular (AV) concordance, and a parallel relationship with D-TGA. As a result, the pulmonary and systemic circulations are separated [the morphological right ventricle (RV) is connected to the aorta and the morphological left ventricle (LV) is connected to the pulmonary artery]. This anomaly is included in the group of developmental disorders of embryonic heart conotruncal irregularities, and their pathogenesis is multifactorial. The anomaly's development is influenced by genetic, epigenetic, and environmental factors. It can occur either as an isolated anomaly, or in association with other cardiac defects. The typical concomitant cardiac anomalies that may occur in patients with D-TGA include ventriculoseptal defects, patent ductus arteriosus, left ventricular outflow tract obstruction (LVOTO), mitral and tricuspid valve abnormalities, and coronary artery variations. Correction of the defect during infancy is the preferred treatment for D-TGA. Balloon atrial septostomy (BAS) is necessary prior to the operation. The recommended surgical correction methods include arterial switch operation (ASO) and atrial switch operation (AtrSR), as well as the Rastelli and Nikaidoh procedures. The most common postoperative complications include coronary artery stenosis, neoaortic root dilation, neoaortic insufficiency and neopulmonic stenosis, right ventricular (RV) outflow tract obstruction (RVOTO), left ventricular (LV) dysfunction, arrhythmias, and heart failure. Early diagnosis and treatment of D-TGA is paramount to the prognosis of the patient. Improved surgical techniques have made it possible for patients with D-TGA to survive into adulthood.

Adverse fetal/neonatal and obstetric outcomes in pregnancies with both maternal and fetal heart disease

OBJECTIVE

To investigate fetal/neonatal and obstetric events in pregnancies with both maternal and fetal heart disease.

STUDY DESIGN

From the CARPREG database, singleton pregnancies (>24 weeks) in patients with structural heart disease that underwent fetal/neonatal echocardiograms were selected and separated in two groups: maternal heart disease only (M-HD) and maternal and fetal heart disease (MF-HD). Differences in adverse fetal/neonatal (death, preterm birth, and small for gestational age) and obstetric (preeclampsia/eclampsia) outcomes between groups were analyzed.

RESULTS

From 1011 pregnancies, 93 had MF-HD. Fetal/neonatal events (38.7% vs 25.3%, p = 0.006) and spontaneous preterm birth (10.8% vs 4.9%, p = 0.021) were more frequent in MF-HD compared to M-HD, with no difference in obstetric events. MF-HD remained as a significant predictor of fetal/neonatal events after adjustment (OR:1.883; 95% CI:1.182-3.000; p = 0.008).

CONCLUSIONS

Pregnancies with MF-HD are at risk of adverse fetal/neonatal events and spontaneous preterm birth. Larger studies are needed to determine their association with preeclampsia.

Pregnancy in women with congenital heart disease: New insights into neonatal risk prediction

BACKGROUND

Advances in managing adult congenital heart disease (ACHD) have led to an increased number of women with CHD reaching childbearing age. This demographic shift underscores the need for improved understanding and prediction of complications during pregnancy in this specific ACHD population. Despite progress in maternal cardiac risk assessment, the prediction of neonatal outcomes for ACHD pregnancies remains underdeveloped. Therefore, the aims of this study are to assess neonatal outcomes in a CHD women population, to identify their predictive factors and to propose a new risk score for predicting neonatal complications.

METHODS

This registry study included all women born between 1975 and 1996 diagnosed with ACHD who underwent at least one cardiology consultation for ACHD in Cliniques Universitaires Saint-Luc. A multivariate analysis was performed to identify predictors of neonatal complications and these were incorporated into a new risk index. Its validity was assessed using bootstrap method. This score was then compared with scores adapted from the ZAHARA and CARPREG studies for offspring events prediction.

RESULTS

Analysis of 491 pregnancies revealed 31.4% of neonatal complications. Four significant predictors of adverse neonatal outcomes were identified: cardiac treatment during pregnancy (OR 14.8, 95%CI [3.4-66]), hypertensive disorders of pregnancy (OR 11.4, 95%CI [3.4-39.0]), smoking during pregnancy (OR 10.6, 95%CI [2.8-40.6]), and pre-pregnancy BMI <18.5 kg/m² (OR 6.5, 95%CI [2.5-16.5]). The risk model demonstrated an AUC of 0.70 (95%CI [0.65-0.75]), which remained stable after bootstrap validation. This model significantly outperformed the scores adapted from ZAHARA and CARPREG data. Based on the regression coefficients, a risk score was subsequently developed comprising five risk categories.

CONCLUSIONS

One third of ACHD pregnancies are complicated by poor neonatal outcome. These complications are determined by four independent factors relating to the cardiac and non-cardiac status of the patients, which have been incorporated into a risk score. Our study is one of the first to propose a predictive risk score of neonatal outcomes in ACHD pregancies, and paves the way for other validation and confirmation studies.

Risk of birth defects in children of mothers with defects

BACKGROUND

There is evidence that women with congenital anomalies are at risk of having an infant with the same defect. However, the risk of having an infant with a different type of defect is less well described.

AIMS

We evaluated the extent to which offspring of women with congenital anomalies were at risk of having a birth defect, including defects that were similar to or different from their mother's.

METHODS

We analyzed a retrospective cohort of 1,311,532 infants born in Canada between 2006 and 2022. The exposure was a maternal congenital anomaly, and the outcome included birth defects in the newborn. We estimated risk ratios (RR) and confidence intervals (CI) for the association of specific maternal anomalies with the risk of having an infant with a similar or different defect using log-binomial regression models adjusted for patient characteristics.

RESULTS

While mothers with anomalies were at risk of having an infant with the same defect, associations with other types of defects were not as strong. For example, compared with no maternal anomaly, maternal urogenital defects were associated with up to 45 times the risk of having an infant with a similar urogenital defect (RR 45.33, 95 % CI 31.92-64.36), but <2 times the risk of having an infant with orofacial clefts (RR 1.89, 95 % CI 1.07-3.34) and clubfoot (RR 1.36, 95 % CI 1.02-1.81).

CONCLUSION

The findings suggest that maternal congenital anomalies are only weakly associated with occurrence of a different type of defect in offspring.

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.

The Utility of Screening Fetal Echocardiograms Following Normal Level II Ultrasounds in Fetuses with Maternal Congenital Heart Disease

INTRODUCTION

Fetal echocardiograms (F-echo) are recommended in all pregnancies when maternal congenital heart disease (CHD) is present, even if there was a prior level II ultrasound (LII-US) that was normal. The goal of this study was to evaluate if any diagnosis of a critical CHD was missed in a fetus with maternal CHD who had a normal LII-US.

METHODS

A retrospective chart review of all F-echoes where the indication was maternal CHD between 1/1/2015 to 12/31/2022 was performed. Fetuses were included if they had a LII-US that was read as normal and had an F-echo. Critical CHD was defined as CHD requiring catheterization or surgical intervention < 1 month of age.

RESULTS

A total of 296 F-echoes on fetuses with maternal CHD were evaluated, of which 175 met inclusion criteria. LII-US was performed at 19.8 ± 2.9 weeks gestational age and F-echo was performed at 24.2 ± 2.8 weeks gestational age. No patient with a normal LII-US had a diagnosis of a critical CHD by F-echo (negative predictive value = 100%). Evaluating those patients that had a negative LII-US, ten patients were diagnosed with non-critical CHD postnatally (negative predictive value = 94.3%). F-echo correctly diagnosed two of the ten missed LII-US CHD.

CONCLUSIONS

Critical CHD was not missed with a normal LII-US in this at risk population. F-echo also missed the majority of CHD when a LII-US was read as normal. A cost-benefit analysis of screening F-echo in fetuses with maternal CHD should be conducted if a normal LII-US has been performed.

Human Genetics of d-Transposition of Great Arteries

Although several genes underlying occurrence of transposition of the great arteries have been found in the mouse, human genetics of the most frequent cyanotic congenital heart defect diagnosed in neonates is still largely unknown. Development of the outflow tract is a complex process which involves the major genes of cardiac development, acting on myocardial cells from the anterior second heart field, and on mesenchymal cells from endocardial cushions. These genes, coding for transcription factors, interact with each other, and their differential expression conditions the severity of the phenotype. A precise description of the anatomic phenotypes is mandatory to achieve a better comprehension of the complex mechanisms responsible for transposition of the great arteries.

Pregnancy Considerations in Tetralogy of Fallot

The majority of women with repaired tetralogy of Fallot are able to tolerate pregnancy with a low risk of cardiovascular events. However, proactive contraceptive advice, prepregnancy counselling, and care by a pregnancy heart team with expertise in congenital heart disease are key to ensuring a good outcome for mother and baby. Maternal and fetal risks are increased in the presence of severe valvular stenosis, poorly tolerated arrhythmia, significant ventricular dysfunction, and cyanosis. It is unusual to see cyanotic adults with tetralogy of Fallot, whether unoperated or shunt palliated; pregnancy risks are greatly reduced by completing their repair before pregnancy is undertaken. The multidisciplinary pregnancy heart team should make a risk-stratified pregnancy care plan using a combination of published scoring systems and an individualized assessment of the patient's comorbidities. Low-risk patients may have the majority of their care and give birth in local units, whereas those at high risk should be managed and give birth in a tertiary centre with high-level expertise and intensive care facilities. Age-appropriate conversations about future childbearing and safe and reliable contraception should be part of routine follow-up from teenage years, so that women with tetralogy of Fallot can control their own fertility and make informed decisions about having children.

Association Between Maternal Factors in Early Pregnancy and Congenital Heart Defects in Offspring: The Japan Environment and Children's Study

Background Many prenatal factors are reported to be associated with congenital heart defects (CHD) in offspring. However, these associations have not been adequately examined using large-scale birth cohorts. Methods and Results We evaluated a data set of the Japan Environmental and Children's Study. The primary outcome was a diagnosis of CHD by age 2 years. We defined the following variables as exposures: maternal baseline characteristics, fertilization treatment, maternal history of diseases, socioeconomic status, maternal alcohol intake, smoking, tea consumption, maternal dietary intake, and maternal medications and supplements up to 12 weeks of gestation. We used multivariable logistic regression analysis to assess the associations between various exposures and CHD in offspring. A total of 91 664 singletons were included, among which 1264 (1.38%) had CHD. In multivariable analysis, vitamin A supplements (adjusted odds ratio [aOR], 5.78 [95% CI, 2.30-14.51]), maternal use of valproic acid (aOR, 4.86 [95% CI, 1.51-15.64]), maternal use of antihypertensive agents (aOR, 3.80 [95% CI, 1.74-8.29]), maternal age ≥40 years (aOR, 1.59 [95% CI, 1.14-2.20]), and high maternal hemoglobin concentration in the second trimester (aOR, 1.10 per g/dL [95% CI, 1.03-1.17]) were associated with CHD in offspring. Conclusions Using a Japanese large-scale birth cohort study, we found 6 maternal factors to be associated with CHD in offspring.

Case-control association study of congenital heart disease from a tertiary paediatric cardiac centre from North India

BACKGROUND

Congenital Heart diseases (CHDs) account for 1/3rd of all congenital birth defects. Etiopathogenesis of CHDs remain elusive despite extensive investigations globally. Phenotypic heterogeneity witnessed in this developmental disorder reiterate gene-environment interactions with periconceptional factors as risk conferring; and genetic analysis of both sporadic and familial forms of CHD suggest its multigenic basis. Significant association of de novo and inherited variants have been observed. Approximately 1/5th of CHDs are documented in the ethnically distinct Indian population but genetic insights have been very limited. This pilot case-control based association study was undertaken to investigate the status of Caucasian SNPs in a north Indian cohort.

METHOD

A total of 306 CHD cases sub-classified into n = 198 acyanotic and n = 108 cyanotic types were recruited from a dedicated tertiary paediatric cardiac centre in Palwal, Haryana. 23 SNPs primarily prioritized from Genome-wide association studies (GWAS) on Caucasians were genotyped using Agena MassARRAY Technology and test of association was performed with adequately numbered controls.

RESULTS

Fifty percent of the studied SNPs were substantially associated in either allelic, genotypic or sub-phenotype categories validating their strong correlation with disease manifestation. Of note, strongest allelic association was observed for rs73118372 in CRELD1 (p < 0.0001) on Chr3, rs28711516 in MYH6 (p = 0.00083) and rs735712 in MYH7 (p = 0.0009) both on Chr 14 and were also significantly associated with acyanotic, and cyanotic categories separately. rs28711516 (p = 0.003) and rs735712 (p = 0.002) also showed genotypic association. Strongest association was observed with rs735712(p = 0.003) in VSD and maximum association was observed for ASD sub-phenotypes.

CONCLUSIONS

Caucasian findings were partly replicated in the north Indian population. The findings suggest the contribution of genetic, environmental and sociodemographic factors, warranting continued investigations in this study population.

Congenitally uncorrected transposition of the great arteries in a pregnant woman 26-year-old: Description and literature review

Complex congenital heart disease and pregnancy are a challenge and delicate medical situation. We describe a first-time pregnancy of a woman living with an uncorrected d-transposition of the great arteries (TGA) with serious fetal complications required multidisciplinary assessment. Twenty-six years old primigravida referred to our cardiology center in 34 weeks of gestation with peripheral cyanosis. The patient was stable hemodynamically and the room air oxygen was at 82%. A continuous murmur systolic and diastolic at second left intercostals space was found. The transthoracic echocardiographic showed an uncorrected TGA with a large atrial defect and patent ductus arteriosus. Obstetrical ultrasonography showed severe intrauterine growth restriction. The patient was delivered by caesarean section under epidural anesthesia with good outcome. This is a case report with discussion of the maternal-fetal outcome of pregnant women with asymptomatic uncorrected TGA. Coordinated care by an informed obstetrician and cardiologist should be the aim.

Evidence-Based Assessment of Congenital Heart Disease Genes to Enable Returning Results in a Genomic Study

BACKGROUND

Congenital heart disease (CHD) is the most common major congenital anomaly and causes significant morbidity and mortality. Epidemiologic evidence supports a role of genetics in the development of CHD. Genetic diagnoses can inform prognosis and clinical management. However, genetic testing is not standardized among individuals with CHD. We sought to develop a list of validated CHD genes using established methods and to evaluate the process of returning genetic results to research participants in a large genomic study.

METHODS

Two-hundred ninety-five candidate CHD genes were evaluated using a ClinGen framework. Sequence and copy number variants involving genes in the CHD gene list were analyzed in Pediatric Cardiac Genomics Consortium participants. Pathogenic/likely pathogenic results were confirmed on a new sample in a clinical laboratory improvement amendments-certified laboratory and disclosed to eligible participants. Adult probands and parents of probands who received results were asked to complete a post-disclosure survey.

RESULTS

A total of 99 genes had a strong or definitive clinical validity classification. Diagnostic yields for copy number variants and exome sequencing were 1.8% and 3.8%, respectively. Thirty-one probands completed clinical laboratory improvement amendments-confirmation and received results. Participants who completed postdisclosure surveys reported high personal utility and no decision regret after receiving genetic results.

CONCLUSIONS

The application of ClinGen criteria to CHD candidate genes yielded a list that can be used to interpret clinical genetic testing for CHD. Applying this gene list to one of the largest research cohorts of CHD participants provides a lower bound for the yield of genetic testing in CHD.

Recurrence pattern of non-syndromic familial congenital heart diseases among a large cohort of families from Egypt

Background

Congenital heart diseases (CHD) are the commonest congenital anomalies with increased risk in children born from families with affected members. However, various recurrence patterns of CHDs have been reported in different populations. Therefore, this work aimed to assess the recurrence patterns of CHDs in a large sample of Egyptian families.

Methods

From January 2020 to October 2021, non-syndromic children with confirmed CHDs were recruited. Data were collected from guardians of the recruited children and hospital records, including the index case’s cardiac diagnosis and CHD diagnosis of other affected family members with to determine their recurrence pattern, consanguinity, and multi-gestation status.

Results

A total of 130 recurrent cases with CHD were documented in 1960 families of children with CHD, including 66,989 members. Most recurrences were detected among first-degree relatives 50/130 (38.46%), especially siblings. Discordant recurrence was the most detected pattern (45.38%), followed by concordant recurrence (42.31%), and the least was group concordance. Recurrence rate was the highest for septal defects with left ventricular outflow tract obstruction (LVOTO) (11.8%) and anomalous venous drainage (11.1%), followed by septal defect with right ventricular outflow tract obstruction (RVOTO) (9.4%), isolated ventricular septal defect (VSD) category (8.2%) and LVOTO (8%). Familial recurrence was significant in consanguineous marriages [p = 0.0001; OR (95%CI) = 4.5 (2.25–9.01)] and in multi-gestations siblings: [p = 0.036; OR (95%CI) = 12.5(1.03–6.04)].

Conclusion

The recurrence of non-syndromic CHD is evident among first-degree relatives in Egyptian families, with mostly a discordant recurrence pattern. Recurrence was more notable in septal defects with LVOTO, anomalous venous drainage, septal defect with RVOTO, isolated VSD, and isolated LVOTO diagnostic categories. This finding will significantly impact family counseling, emphasizing higher recurrence in consanguineous parents.

Supplementary information

The online version contains supplementary material available at 10.1186/s12887-022-03640-4.

Risk of Congenital Heart Defects in Offspring of Affected Mothers and Fathers

Background:

Smaller studies have reported a higher offspring risk of congenital heart defects (CHDs) for mothers with CHDs than for fathers with CHDs. In a large population-based study, we investigated whether offspring risk of CHD differed for mothers and fathers with CHDs.

Methods:

All people born in Denmark, 1977 to 2011, with at least 1 registered parent, were included in our cohort (n=2 341 061). Parent-child recurrence of CHDs was evaluated using risk ratios (RRs) comparing risks of CHDs in individuals with and without a parent with a CHD, estimated using log-linear binomial regression.

Results:

The RRs for any CHD in offspring were 5.39 (95% CI, 4.88–5.96) for mothers and 3.04 (95% CI, 2.59–3.57) for fathers affected with any CHD; the ratio of RRs for mothers versus fathers was 1.82 ( P <0.0001). Recurrence RRs for the same cardiac phenotype in parent and offspring were significantly stronger for mothers than for fathers for conotruncal defects (ratio of RRs, 4.98), left ventricular outlet tract obstruction (ratio of RRs, 4.98), and ventricular septal defects (ratio of RRs, 2.51) but not for atrioventricular septal defects (ratio of RRs, 1.06). Birth rates among people with CHDs, relative to the general population, were 18% higher for women than for men, regardless of parental cardiac phenotype.

Conclusions:

Recurrence risks of CHDs were significantly greater in the offspring of affected women than in the offspring of affected men. The excess maternal recurrence risks could not be explained by the slightly higher birth rates in women with CHDs.

Right ventricular outflow tract anomalies: Neonatal interventions and outcomes

Right ventricular outflow tract (RVOT) anomalies comprise a wide spectrum of congenital heart disease, typically characterized by obstruction to flow from the right ventricle to pulmonary arteries. This review highlights important considerations surrounding management strategy as well as clinical outcomes for the neonate with RVOT anomaly, including: pulmonary atresia with intact ventricular septum, congenital pulmonary valve stenosis, tetralogy of Fallot, and Ebstein anomaly with anatomic or physiologic RVOT obstruction.

Whole genome sequencing in transposition of the great arteries and associations with clinically relevant heart, brain and laterality genes

BACKGROUND

The most common cyanotic congenital heart disease (CHD) requiring management as a neonate is transposition of great arteries (TGA). Clinically, up to 50% of TGA patients develop some form of neurodevelopmental disability (NDD), thought to have a significant genetic component. A "ciliopathy" and links with laterality disorders have been proposed. This first report of whole genome sequencing in TGA, sought to identify clinically relevant variants contributing to heart, brain and laterality defects.

METHODS

Initial whole genome sequencing analyses on 100 TGA patients focussed on established disease genes related to CHD (n = 107), NDD (n = 659) and heterotaxy (n = 74). Single variant as well as copy number variant analyses were conducted. Variant pathogenicity was assessed using the American College of Medical Genetics and Genomics-Association for Molecular Pathology guidelines.

RESULTS

Fifty-five putatively damaging variants were identified in established disease genes associated with CHD, NDD and heterotaxy; however, no clinically relevant variants could be attributed to disease. Notably, case-control analyses identified significantly more predicted-damaging, silent and total variants in TGA cases than healthy controls in established CHD genes (P < .001), NDD genes (P < .001) as well as across the three gene panels (P < .001).

CONCLUSION

We present compelling evidence that the majority of TGA is not caused by monogenic rare variants and is most likely oligogenic and/or polygenic in nature, highlighting the complex genetic architecture and multifactorial influences on this CHD sub-type and its long-term sequelae. Assessment of variant burden in key heart, brain and/or laterality genes may be required to unravel the genetic contributions to TGA and related disabilities.

Common Genetic Variants Contribute to Risk of Transposition of the Great Arteries

RATIONALE

Dextro-transposition of the great arteries (D-TGA) is a severe congenital heart defect which affects approximately 1 in 4,000 live births. While there are several reports of D-TGA patients with rare variants in individual genes, the majority of D-TGA cases remain genetically elusive. Familial recurrence patterns and the observation that most cases with D-TGA are sporadic suggest a polygenic inheritance for the disorder, yet this remains unexplored.

OBJECTIVE

We sought to study the role of common single nucleotide polymorphisms (SNPs) in risk for D-TGA.

METHODS AND RESULTS

We conducted a genome-wide association study in an international set of 1,237 patients with D-TGA and identified a genome-wide significant susceptibility locus on chromosome 3p14.3, which was subsequently replicated in an independent case-control set (rs56219800, meta-analysis P=8.6x10-10, OR=0.69 per C allele). SNP-based heritability analysis showed that 25% of variance in susceptibility to D-TGA may be explained by common variants. A genome-wide polygenic risk score derived from the discovery set was significantly associated to D-TGA in the replication set (P=4x10-5). The genome-wide significant locus (3p14.3) co-localizes with a putative regulatory element that interacts with the promoter of WNT5A, which encodes the Wnt Family Member 5A protein known for its role in cardiac development in mice. We show that this element drives reporter gene activity in the developing heart of mice and zebrafish and is bound by the developmental transcription factor TBX20. We further demonstrate that TBX20 attenuates Wnt5a expression levels in the developing mouse heart.

CONCLUSIONS

This work provides support for a polygenic architecture in D-TGA and identifies a susceptibility locus on chromosome 3p14.3 near WNT5A. Genomic and functional data support a causal role of WNT5A at the locus.

Genomic frontiers in congenital heart disease

The application of next-generation sequencing to study congenital heart disease (CHD) is increasingly providing new insights into the causes and mechanisms of this prevalent birth anomaly. Whole-exome sequencing analysis identifies damaging gene variants altering single or contiguous nucleotides that are assigned pathogenicity based on statistical analyses of families and cohorts with CHD, high expression in the developing heart and depletion of damaging protein-coding variants in the general population. Gene classes fulfilling these criteria are enriched in patients with CHD and extracardiac abnormalities, evidencing shared pathways in organogenesis. Developmental single-cell transcriptomic data demonstrate the expression of CHD-associated genes in particular cell lineages, and emerging insights indicate that genetic variants perturb multicellular interactions that are crucial for cardiogenesis. Whole-genome sequencing analyses extend these observations, identifying non-coding variants that influence the expression of genes associated with CHD and contribute to the estimated ~55% of unexplained cases of CHD. These approaches combined with the assessment of common and mosaic genetic variants have provided a more complete knowledge of the causes and mechanisms of CHD. Such advances provide knowledge to inform the clinical care of patients with CHD or other birth defects and deepen our understanding of the complexity of human development. In this Review, we highlight known and candidate CHD-associated human genes and discuss how the integration of advances in developmental biology research can provide new insights into the genetic contributions to CHD.

Rare variants in KDR, encoding VEGF Receptor 2, are associated with tetralogy of Fallot

PURPOSE

Rare genetic variants in KDR, encoding the vascular endothelial growth factor receptor 2 (VEGFR2), have been reported in patients with tetralogy of Fallot (TOF). However, their role in disease causality and pathogenesis remains unclear.

METHODS

We conducted exome sequencing in a familial case of TOF and large-scale genetic studies, including burden testing, in >1,500 patients with TOF. We studied gene-targeted mice and conducted cell-based assays to explore the role of KDR genetic variation in the etiology of TOF.

RESULTS

Exome sequencing in a family with two siblings affected by TOF revealed biallelic missense variants in KDR. Studies in knock-in mice and in HEK 293T cells identified embryonic lethality for one variant when occurring in the homozygous state, and a significantly reduced VEGFR2 phosphorylation for both variants. Rare variant burden analysis conducted in a set of 1,569 patients of European descent with TOF identified a 46-fold enrichment of protein-truncating variants (PTVs) in TOF cases compared to controls (P = 7 × 10-11).

CONCLUSION

Rare KDR variants, in particular PTVs, strongly associate with TOF, likely in the setting of different inheritance patterns. Supported by genetic and in vivo and in vitro functional analysis, we propose loss-of-function of VEGFR2 as one of the mechanisms involved in the pathogenesis of TOF.

The Mathematical Limitations of Fetal Echocardiography as a Screening Tool in the Setting of a Normal Second-Trimester Ultrasound

Background

The effectiveness of screening strategies targeting pregnancies at higher risk of congenital heart disease (CHD) is reduced by the low prevalence of severe CHD, the increase in CHD detection rates by second-trimester ultrasound (U/S), and the high proportion of severe CHD in low-risk pregnancies. We aimed to determine situations in which additional screening by fetal echocardiography (FE) would result in a significant increase in sensitivity and a sizable decrease in the false-negative rate of detection of severe CHD.

Methods

We simulated the change in the numbers of detected severe CHD cases when FE is offered to women with a normal second-trimester U/S who have a higher risk of bearing a child with CHD, compared to U/S alone. The primary outcome was the increase in sensitivity. Secondary outcomes were the number needed to screen and the reduction in the rate of missed cases.

Results

For an U/S sensitivity of 60%, the addition of FE in pregnancies at high risk of CHD (risk ratio 3.5; range: 2 to 5) increased sensitivity by 2.4 percentage points (1.1 to 7.9). The number needed to screen to detect one additional case of severe CHD was 436 (156 to 952). The rate of additional severe CHD cases detected by FE was 4 per 100,000 pregnancies (2 to 32).

Conclusions

The addition of FE to U/S for severe CHD prenatal screening in pregnancies at high risk of CHD yielded marginal benefits in terms of increased sensitivity and decreased rates of false negatives, at the expense of significant resource utilization.

The Importance of Cardiovascular Risk Assessment and Pregnancy Heart Team in the Management of Cardiovascular Disease in Pregnancy

Pregnancy-related maternal morbidity and mortality is increasing because of complications from cardiovascular disease. Pregnancy results in physiologic changes that can adversely impact the cardiovascular system and lead to adverse pregnancy outcomes. A multidisciplinary pregnancy heart team is essential to safely navigate women with heart disease through pregnancy. This role of the pregnancy heart team is to offer preconception counseling, determine pregnancy risks and educate women about those risks, develop a comprehensive antenatal and delivery plan, and ensure appropriate postpartum follow-up. These steps are important to improve cardiovascular outcomes in pregnancy.

Mending a broken heart: In vitro, in vivo and in silico models of congenital heart disease

Birth defects contribute to ∼0.3% of global infant mortality in the first month of life, and congenital heart disease (CHD) is the most common birth defect among newborns worldwide. Despite the significant impact on human health, most treatments available for this heterogenous group of disorders are palliative at best. For this reason, the complex process of cardiogenesis, governed by multiple interlinked and dose-dependent pathways, is well investigated. Tissue, animal and, more recently, computerized models of the developing heart have facilitated important discoveries that are helping us to understand the genetic, epigenetic and mechanobiological contributors to CHD aetiology. In this Review, we discuss the strengths and limitations of different models of normal and abnormal cardiogenesis, ranging from single-cell systems and 3D cardiac organoids, to small and large animals and organ-level computational models. These investigative tools have revealed a diversity of pathogenic mechanisms that contribute to CHD, including genetic pathways, epigenetic regulators and shear wall stresses, paving the way for new strategies for screening and non-surgical treatment of CHD. As we discuss in this Review, one of the most-valuable advances in recent years has been the creation of highly personalized platforms with which to study individual diseases in clinically relevant settings.

Fetal Echocardiography is Useful for Screening Fetuses with a Family History of Cardiomyopathy

We screened all fetal echocardiograms performed at our institution for the past 5 years for the indication of family history of cardiomyopathy. Twenty-six patients were identified who had fetal echocardiograms performed due to a family history of cardiomyopathy. Three out of 26 patients (11.5%) had findings of decreased ventricular function and dilation consistent with cardiomyopathy. All who had cardiomyopathy on fetal echocardiography had parents with genetic mutations (2 maternal, 1 paternal), including one mother who had a cardiac transplant at age 8 for dilated cardiomyopathy. All 3 affected infants had prenatal planning for high level care and were transferred to our facility immediately after birth for cardiology evaluation and management. 2 patients required inotropic support in the newborn period. One patient was transplanted at age 2 months. One patient required ECMO support for one week and initially recovered, but subsequently required mechanical support and listing for heart transplant. We recommend patients with a strong family history of cardiomyopathy in either parent, especially those with known genetic mutations associated with cardiomyopathy, have fetal echocardiograms performed.

Evidence for germline non-genetic inheritance of human phenotypes and diseases

It is becoming increasingly apparent that certain phenotypes are inherited across generations independent of the information contained in the DNA sequence, by factors in germ cells that remain largely uncharacterized. As evidence for germline non-genetic inheritance of phenotypes and diseases continues to grow in model organisms, there are fewer reports of this phenomenon in humans, due to a variety of complications in evaluating this mechanism of inheritance in humans. This review summarizes the evidence for germline-based non-genetic inheritance in humans, as well as the significant challenges and important caveats that must be considered when evaluating this process in human populations. Most reports of this process evaluate the association of a lifetime exposure in ancestors with changes in DNA methylation or small RNA expression in germ cells, as well as the association between ancestral experiences and the inheritance of a phenotype in descendants, down to great-grandchildren in some cases. Collectively, these studies provide evidence that phenotypes can be inherited in a DNA-independent manner; the extent to which this process contributes to disease development, as well as the cellular and molecular regulation of this process, remain largely undefined.

Genetic Basis of Human Congenital Heart Disease

Congenital heart disease (CHD) is the most common major congenital anomaly with an incidence of ∼1% of live births and is a significant cause of birth defect-related mortality. The genetic mechanisms underlying the development of CHD are complex and remain incompletely understood. Known genetic causes include all classes of genetic variation including chromosomal aneuploidies, copy number variants, and rare and common single-nucleotide variants, which can be either de novo or inherited. Among patients with CHD, ∼8%-12% have a chromosomal abnormality or aneuploidy, between 3% and 25% have a copy number variation, and 3%-5% have a single-gene defect in an established CHD gene with higher likelihood of identifying a genetic cause in patients with nonisolated CHD. These genetic variants disrupt or alter genes that play an important role in normal cardiac development and in some cases have pleiotropic effects on other organs. This work reviews some of the most common genetic causes of CHD as well as what is currently known about the underlying mechanisms.

Genetics in congenital heart disease. Are we ready for it?

Genetics has rightly acquired an important place in almost all medical disciplines in recent years and this is certainly the case in the field of congenital cardiology. Not only has this led to greater insight into the pathophysiology of congenital heart defects but it also has a beneficial impact on patient management. Integration of clinical genetics in multidisciplinary centers of expertise for CHD is therefore a clear recommendation. Adult and pediatric cardiologists play a crucial role in the process of genetic evaluation of patients and families and should have be familiar with red flags for referral for further clinical genetic elaboration, counseling, and eventual testing. Some basic knowledge is also important for the correct interpretation of genetic testing results. In this review article, we provide a practical overview of what genetic evaluation entails, which type of genetic tests are possible today, and how this can be used in practice for the individual patient.

The evolution of fetal echocardiography before and during COVID-19

The World Health Organization declared the novel coronavirus, or COVID-19, a pandemic in March 2020. Given the severity of COVID-19, appropriate use criteria have been implemented for fetal echocardiography. Screening low risk pregnancies for critical congenital heart disease has typically been a shared responsibility by pediatric cardiologists, obstetricians, and maternal fetal medicine (MFM). Currently, many of the fetal echocardiograms for low risk pregnancies for critical congenital heart disease have been deferred or cancelled with the emphasis on suspected abnormalities by MFMs and obstetricians. In this review, we discuss the literature that has been the basis of screening of low risk pregnancies by pediatric cardiologists. A new approach to more widespread usage of fetal tele-echocardiography may play a large part during COVID-19 and may continue after the pandemic.

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Appropriate use criteria for fetal echocardiography have been implemented during the COVID-19 pandemic.

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Pediatric cardiologists have deferred fetal echo for low risk pregnancies, emphasizing those with suspected abnormalities.

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Current fetal echo guidelines highlight maternal, familial, and fetal risk factors, and the associated incidence of CHD.

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Fetal tele-echocardiography and telehealth consultation may enhance the ability to provide care during and beyond COVID-19.

Whole Exome Sequencing Reveals the Major Genetic Contributors to Nonsyndromic Tetralogy of Fallot

RATIONALE

Familial recurrence studies provide strong evidence for a genetic component to the predisposition to sporadic, nonsyndromic Tetralogy of Fallot (TOF), the most common cyanotic congenital heart disease phenotype. Rare genetic variants have been identified as important contributors to the risk of congenital heart disease, but relatively small numbers of TOF cases have been studied to date.

OBJECTIVE

We used whole exome sequencing to assess the prevalence of unique, deleterious variants in the largest cohort of nonsyndromic TOF patients reported to date.

METHODS AND RESULTS

Eight hundred twenty-nine TOF patients underwent whole exome sequencing. The presence of unique, deleterious variants was determined; defined by their absence in the Genome Aggregation Database and a scaled combined annotation-dependent depletion score of ≥20. The clustering of variants in 2 genes, NOTCH1 and FLT4, surpassed thresholds for genome-wide significance (assigned as P<5×10^-8) after correction for multiple comparisons. NOTCH1 was most frequently found to harbor unique, deleterious variants. Thirty-one changes were observed in 37 probands (4.5%; 95% CI, 3.2%-6.1%) and included 7 loss-of-function variants 22 missense variants and 2 in-frame indels. Sanger sequencing of the unaffected parents of 7 cases identified 5 de novo variants. Three NOTCH1 variants (p.G200R, p.C607Y, and p.N1875S) were subjected to functional evaluation, and 2 showed a reduction in Jagged1-induced NOTCH signaling. FLT4 variants were found in 2.4% (95% CI, 1.6%-3.8%) of TOF patients, with 21 patients harboring 22 unique, deleterious variants. The variants identified were distinct to those that cause the congenital lymphoedema syndrome Milroy disease. In addition to NOTCH1, FLT4 and the well-established TOF gene, TBX1, we identified potential association with variants in several other candidates, including RYR1, ZFPM1, CAMTA2, DLX6, and PCM1.

CONCLUSIONS

The NOTCH1 locus is the most frequent site of genetic variants predisposing to nonsyndromic TOF, followed by FLT4. Together, variants in these genes are found in almost 7% of TOF patients.

Familial co-occurrence of congenital heart defects follows distinct patterns

Aims

Congenital heart defects (CHD) affect almost 1% of all live born children and the number of adults with CHD is increasing. In families where CHD has occurred previously, estimates of recurrence risk, and the type of recurring malformation are important for counselling and clinical decision-making, but the recurrence patterns in families are poorly understood. We aimed to determine recurrence patterns, by investigating the co-occurrences of CHD in 1163 families with known malformations, comprising 3080 individuals with clinically confirmed diagnosis.

Methods and results

We calculated rates of concordance and discordance for 41 specific types of malformations, observing a high variability in the rates of concordance and discordance. By calculating odds ratios for each of 1640 pairs of discordant lesions observed between affected family members, we were able to identify 178 pairs of malformations that co-occurred significantly more or less often than expected in families. The data show that distinct groups of cardiac malformations co-occur in families, suggesting influence from underlying developmental mechanisms. Analysis of human and mouse susceptibility genes showed that they were shared in 19% and 20% of pairs of co-occurring discordant malformations, respectively, but none of malformations that rarely co-occur, suggesting that a significant proportion of co-occurring lesions in families is caused by overlapping susceptibility genes.

Conclusion

Familial CHD follow specific patterns of recurrence, suggesting a strong influence from genetically regulated developmental mechanisms. Co-occurrence of malformations in families is caused by shared susceptibility genes.

Genetic Basis for Congenital Heart Disease: Revisited: A Scientific Statement From the American Heart Association

This review provides an updated summary of the state of our knowledge of the genetic contributions to the pathogenesis of congenital heart disease. Since 2007, when the initial American Heart Association scientific statement on the genetic basis of congenital heart disease was published, new genomic techniques have become widely available that have dramatically changed our understanding of the causes of congenital heart disease and, clinically, have allowed more accurate definition of the pathogeneses of congenital heart disease in patients of all ages and even prenatally. Information is presented on new molecular testing techniques and their application to congenital heart disease, both isolated and associated with other congenital anomalies or syndromes. Recent advances in the understanding of copy number variants, syndromes, RASopathies, and heterotaxy/ciliopathies are provided. Insights into new research with congenital heart disease models, including genetically manipulated animals such as mice, chicks, and zebrafish, as well as human induced pluripotent stem cell-based approaches are provided to allow an understanding of how future research breakthroughs for congenital heart disease are likely to happen. It is anticipated that this review will provide a large range of health care-related personnel, including pediatric cardiologists, pediatricians, adult cardiologists, thoracic surgeons, obstetricians, geneticists, genetic counselors, and other related clinicians, timely information on the genetic aspects of congenital heart disease. The objective is to provide a comprehensive basis for interdisciplinary care for those with congenital heart disease.

Secular trends in pregnancy rates, delivery outcomes, and related health care utilization among women with congenital heart disease

BACKGROUND

The number of women with congenital heart disease (CHD) of reproductive age is increasing, yet a description of trends in pregnancy and delivery outcomes in this population is lacking.

OBJECTIVE

To assess secular trends in pregnancy rates, delivery outcomes, and related health care utilization in the adult female CHD population in Quebec, Canada.

METHODS

The Quebec CHD database was used to construct a cohort with all women with CHD aged 18-45 years between 1992 and 2004. Pregnancy and delivery rates were determined yearly and compared to the general population. Secular trends in pregnancy and delivery rates were assessed with linear regression. The cesarean delivery rate in the CHD population was compared to the general population. Predictors of cesarean section were determined with multivariable logistic regression. Cox regression, adjusted for comorbidities, was used to analyze the impact of cesarean sections on 1-year health care use following delivery.

RESULTS

About 14 878 women were included. A total of 10 809 pregnancies were identified in 5641 women, of whom 4551 (80%) and 2528 (45%) experienced at least one delivery and/or abortion, respectively. Absolute yearly numbers and rates of pregnancies and deliveries increased during the study period (P < .05). The increment in cesarean section rates was more pronounced among women with CHD than among the general population. Gestational diabetes (OR 1.50, 95% CI [1.13, 1.99]), gestational hypertension (OR 1.81, 95% CI [1.27, 2.57]), and preeclampsia (OR 1.59, 95% CI [1.11, 2.8]) were independent predictors of cesarean delivery. Cesarean sections were associated with postpartum cardiac-hospitalization within 1 year following delivery (HR = 2.35, 95% CI [1.05, 5.28]).

CONCLUSIONS

Yearly numbers and rates of pregnancies and deliveries in adult females with CHD rose significantly during the study period. Cesarean sections led to increased health care utilization. Further research is required to determine causes of high cesarean section rates in this patient population.

Outcomes of Pregnancy After Right Ventricular Outflow Tract Reconstruction With an Allograft Conduit

BACKGROUND

There is no published evidence on pregnancy after right ventricular outflow tract (RVOT) reconstruction with an allograft.

OBJECTIVES

The aim of this study was to describe pregnancy outcomes in women with allografts in the RVOT position.

METHODS

A retrospective cohort study of consecutive female patients who received allografts in the RVOT position was conducted. All patients between 18 and 50 years of age were screened for cardiac, obstetric, and fetal outcomes of completed (≥20 weeks' gestation) pregnancies.

RESULTS

In total, 196 women met the inclusion criteria, of whom 56 had 89 completed pregnancies. Information could be retrieved in 84 cases (94.4%). Mean maternal age was 29.6 ± 4.3 years, with 80 patients (95.2%) in New York Heart Association functional class I or II. The most common diagnosis was tetralogy of Fallot. All women survived pregnancy. There were 2 cases (2.4%) of heart failure (arrhythmic and diastolic dysfunction), 1 case (1.2%) of infection (chorioamnionitis), and 3 cases (3.6%) of pre-eclampsia. No other cardiac or obstetric events were reported. All children were born alive at a median gestational age of 38.4 weeks (interquartile range: 36.9 to 39.6 weeks), with a median birthweight of 2,930 g (interquartile range: 2,535 to 3,385 g). Seventeen (20.2%) were small for gestational age, and 20 (23.8%) were premature. Neonatal death was reported in 2 children (2.5%). Preconception pulmonary regurgitation was associated with an increased probability of pre-term labor (odds ratio: 2.610; 95% confidence interval: 1.318 to 5.172). Compared with the general Dutch population, pre-term delivery (25.0% vs. 7.4%, p < 0.001) and children small for gestational age (20.2% vs. 10.0%, p = 0.002) were more common.

CONCLUSIONS

Women in good cardiac health after RVOT reconstruction with allografts can safely experience pregnancy and labor. The higher incidence of pre-term delivery and children small for gestational age warrants special attention.

Risk factors for congenital heart defects in two populations residing in the same geographic area: a long-term population-based study, Southern Israel

BACKGROUND

Congenital Heart Defects (CHD) are the most common structural defects of newborns. Southern Israel's population is comprised of Jews (75%) and Arab-Bedouins (25%). The latter has a high rate of consanguinity and low abortion rate compared with the Jewish population, which led us to suspect a higher CHD prevalence in this population. Our aim was to compare maternal risk factors that are associated with CHD in these populations.

METHODS

All births during 1991-2011 in Soroka University Medical Center (n = 247, 289) with 6078 newborns having CHD were included. To account for same-woman deliveries, general estimating equation models adjusted for ethnicity, gender and birth number were used.

RESULTS

The total prevalence of CHD was 24.6/1000 live births, with 21.4 and 30 among Jewish and Bedouin populations, respectively, (p = 0.001). Multi-variant analysis of risk factors for CHD revealed that risk factors common to both populations included conception with fertility medications, sibling CHD, maternal CHD, diabetes mellitus, hypertension and anaemia. Risk factors that were specific for the Bedouin population were - maternal age over 35 years, recurrent pregnancy loss and in vitro fertilisation. However, sibling CHD was more common as a CHD risk factor in the Jewish compared with the Bedouin population (Adjusted OR 10.23 versus 3.19, respectively).

CONCLUSIONS

The prevalence of CHD is higher in both the Bedouin and Jewish populations than previously reported. Several maternal factors were associated with CHD specifically for a certain population. Risk factors for CHD vary in populations residing in the same geographic area.

Recurrent Congenital Heart Diseases Among Neonates Born to Mothers with Congenital Heart Diseases

The frequency of newborns with congenital heart disease (CHD) is approximately 1% in the general population; however, the recurrence rate of CHD in mothers with CHD differs in ethnicity and reports. We therefore aimed to determine the prevalence of CHD among neonates born to mothers with CHD in our institute in Japan. We reviewed the medical charts of 803 neonates delivered by 529 women with CHD at the National Cerebral and Cardiovascular Center from 1982 to 2016. They included isolated ventricular septal defect (VSD,31.4%), isolated atrial septal defect (ASD, 23.3%), tetralogy of Fallot (TOF,10.6%). We defined CHD in neonates as being diagnosed within 1 month of birth. We estimated that the average rate of the CHD recurrence was 3.1%. The recurrence ratios in each maternal CHD were 8.6%, 7.1%, 6.2%, 4.8%, 3.6%, and 1.5% for PS, CoA, TOF, atrioventricular septal defect, VSD, and ASD, respectively. The rate of CHD in offsprings whose mothers have CHD was 3 times greater than that of mothers with healthy hearts. Almost half of neonates with CHD had the same phenotype as their mother in our series. Especially, PS and CoA were closely related to the type of maternal CHD.

Maternal Congenital Heart Disease in Pregnancy

Congenital heart disease comprises most maternal cardiac diseases in pregnancy and is an important cause of maternal, fetal, and neonatal morbidity and mortality worldwide. Pregnancy is often considered a high-risk state for individuals with structural heart disease as a consequence of a limited ability to adapt to the major hemodynamic changes associated with pregnancy. Preconception counseling and evaluation are of utmost importance, as pregnancy is contraindicated in certain cardiac conditions. Pregnancy can be safely accomplished in most individuals with careful risk assessment before conception and multidisciplinary care throughout pregnancy and the postpartum period.

Impact of Improved Survival in Congenital Heart Disease on Incidence of Disease

Survival rates and life expectancies for patients with congenital heart disease (CHD) have dramatically increased, and these patients are now reaching reproductive age. As they reproduce, questions pertaining to recurrent risk of disease and the impact on incidence rates have emerged. Recurrence rates for CHD have been estimated at 3% to 5%, although, due to the complex genetics underlying CHD, this range may represent an underestimation of the true risk. Debate still exists on whether the impact of recurrence of disease has been reflected in incidence rates. Although incidence rates have undoubtedly increased, the mechanism underlying this remains unclear; improved detection likely accounts for the majority of the observed increase; however, a true increase may be present simultaneously. Concurrently, certain factors, including improved fetal detection and elective terminations, infertility, increased rates of spontaneous abortion and intrauterine fetal demise in women with CHD, and folic acid supplementation, are leading to decreases in the incidence of CHD. It is likely that the full impact of improved survival and heritability of CHD on incidence rates remains to be seen and will likely be attenuated by other factors acting to decrease incidence.

Congenital Heart Disease and Reproductive Risk: An Overview for Obstetricians, Cardiologists, and Primary Care Providers

Patients with congenital heart disease have improved survival rates, and most patients are now expected to survive into adulthood. This improved survival has resulted in increasing numbers of women with congenital heart disease who are of childbearing age. This patient population requires specialized advice on contraception and pregnancy risk. Understanding the unique challenges this population presents is key to providing appropriate care.

Pregnancy in Women with Cardiovascular Diseases

Patients with cardiovascular disease represent a significant cohort at risk for complications during pregnancy. The normal physiologic changes of pregnancy could further compromise the hemodynamics of various cardiovascular conditions, resulting in clinical deterioration and even death. The fetus of a gravida with cardiovascular disease also has an increased risk of morbidity, including an increased risk of inherited cardiac genetic disorders, fetal growth restriction, and premature delivery. These complications also increase the risk for antenatal and perinatal mortality. Ideally, the management of a patient with cardiac disease who is considering pregnancy should start with pre-conception counseling that outlines the maternal and fetal complications associated with her particular cardiac disorder. The pregnancy is best managed by a dedicated team of specialists in maternal-fetal medicine, cardiology, cardiovascular surgery, anesthesiology, and neonatology, preferably in a tertiary care center.

Two Brothers With Dextro-Transposition of the Great Arteries

Dextro-transposition of the great arteries (d-TGA) is a common cause of cyanotic heart disease in neonates. Current thought is d-TGA is a sporadic occurrence in families with an unclear etiology. We describe a case of brothers with d-TGA. Genetic testing revealed that both are heterozygous for two gene variations that are associated with congenital heart disease.

Some Isolated Cardiac Malformations Can Be Related to Laterality Defects

Human beings are characterized by a left–right asymmetric arrangement of their internal organs, and the heart is the first organ to break symmetry in the developing embryo. Aberrations in normal left–right axis determination during embryogenesis lead to a wide spectrum of abnormal internal laterality phenotypes, including situs inversus and heterotaxy. In more than 90% of instances, the latter condition is accompanied by complex and severe cardiovascular malformations. Atrioventricular canal defect and transposition of the great arteries—which are particularly frequent in the setting of heterotaxy—are commonly found in situs solitus with or without genetic syndromes. Here, we review current data on morphogenesis of the heart in human beings and animal models, familial recurrence, and upstream genetic pathways of left–right determination in order to highlight how some isolated congenital heart diseases, very common in heterotaxy, even in the setting of situs solitus, may actually be considered in the pathogenetic field of laterality defects.

Genomics and Epigenomics of Congenital Heart Defects: Expert Review and Lessons Learned in Africa

Congenital heart defects (CHD) are structural malformations found at birth with a prevalence of 1%. The clinical trajectory of CHD is highly variable and thus in need of robust diagnostics and therapeutics. Major surgical interventions are often required for most CHDs. In Africa, despite advances in life sciences infrastructure and improving education of medical scholars, the limited clinical data suggest that CHD detection and correction are still not at par with the rest of the world. But the toll and genetics of CHDs in Africa has seldom been systematically investigated. We present an expert review on CHD with lessons learned on Africa. We found variable CHD phenotype prevalence in Africa across countries and populations. There are important gaps and paucity in genomic studies of CHD in African populations. Among the available genomic studies, the key findings in Africa were variants in GATA4 (P193H), MTHFR 677TT, and MTHFR 1298CC that were associated with atrial septal defect, ventricular septal defect (VSD), Tetralogy of Fallot (TOF), and patent ductus arteriosus phenotypes and 22q.11 deletion, which is associated with TOF. There were no data on epigenomic association of CHD in Africa, however, other studies have shown an altered expression of miR-421 and miR-1233-3p to be associated with TOF and hypermethylation of CpG islands in the promoter of SCO2 gene also been associated with TOF and VSD in children with non-syndromic CHD. These findings signal the urgent need to develop and implement genetic and genomic research on CHD to identify the hereditary and genome-environment interactions contributing to CHD. These projected studies would also offer comparisons on CHD pathophysiology between African and other populations worldwide. Genomic research on CHD in Africa should be developed in parallel with next generation technology policy research and responsible innovation frameworks that examine the social and political factors that shape the emergence and societal embedding of new technologies.

NRP1 haploinsufficiency predisposes to the development of Tetralogy of Fallot

Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart defect. It involves anatomical abnormalities that change the normal flow of blood through the heart resulting in low oxygenation. Although not all of the underlying causes of TOF are completely understood, the disease has been associated with varying genetic etiologies including chromosomal abnormalities and Mendelian disorders, but can also occur as an isolated defect. In this report, we describe a familial case of TOF associated with a 1.8 Mb deletion of chromosome 10p11. Among the three genes in the region one is Neuropilin1 (NRP1), a membrane co-receptor of VEGF that modulates vasculogenesis. Hemizygous levels of NRP1 resulted in a reduced expression at the transcriptional and protein levels in patient-derived cells. Reduction of NRP1 also lead to decreased function of its activity as a co-receptor in intermolecular VEGF signaling. These findings support that diminished levels of NRP1 contribute to the development of TOF, likely through its function in mediating VEGF signal and vasculogenesis.

MTHFR A1298C polymorphisms reduce the risk of congenital heart defects: a meta-analysis from 16 case-control studies

Background

Methylenetetrahydrofolate reductase (MTHFR) plays a crucial role in the hyperhomocysteinemia, which is a risk factor related to the occurrence of congenital heart defect (CHD). However, the association between MTHFR polymorphism and CHD has been inconclusive.

Methods

We conducted an updated meta-analysis to provide comprehensive evidence on the role of MTHFR A1298C polymorphism in CHD. Databases were searched and a total of 16 studies containing 2207 cases and 2364 controls were included.

Results

We detected that a significant association was found in the recessive model (CC vs. AA + AC: OR = 1.38, 95% CI: 1.10–1.73) for the overall population. Subgroup analysis showed that associations were found in patients without Down Syndrome in genetic models for CC vs. AA (OR = 1.47, 95% CI: 1.01–2.14), CC vs. AC (OR = 1.29, 95% CI: 1.00–1.66) and recessive model (OR = 1.44, 95% CI: 1.14–1.82). We conducted a meta-regression analysis, Galbraith plots and a sensitivity analysis to assess the sources of heterogeneity.

Conclusions

In summary, our present meta-analysis supports the MTHFR 1298C allele as a risk factor for CHD. However, further studies should be conducted to investigate the correlation of plasma homocysteine levels, enzyme activity, and periconceptional folic acid supplementation with the risk of CHD.

Electronic supplementary material

The online version of this article (10.1186/s13052-017-0425-1) contains supplementary material, which is available to authorized users.