Congenital heart defects--chromosomal anomalies, syndromes and extracardiac malformations

Morbidity and mortality in premature or low birth weight patients with congenital heart disease in three European pediatric heart centers between 2016 and 2020

Background

The treatment of preterm and low birth weight (LBW) neonates born with congenital heart disease (CHD) requiring early cardiac intervention remains challenging. We aimed to analyze morbidity and mortality in this combined high-risk patient group.

Methods

A retrospective cohort study was conducted of preterm [<37 weeks gestational age (GA)] and/or LBW neonates (<2,500 g) born with a diagnosis of CHD, which requires invasive cardiac intervention (surgery or catheter) within their first year of life. Patients born between 2016 and 2020 and treated in three European pediatric heart centers were included.

Results

A total of 308 neonates (51% male) with CHD were included. Of those, 237 (77%) were born preterm, 259 (84%) were LBW, and 188 (61%) were both. The median GA was 35.4 weeks (interquartile range 33.3-36.9) and the mean birth weight was 2,016 ± 580 g. CHD was categorized as simple (12%), moderate (64%), or severe (24%). The overall complication rate was 45% and was highest in patients with severe CHD (p = 0.002). One-year mortality (19%) was associated with severe CHD, low relative birth weight in patients with genetic diagnoses, and low GA at birth, whereas GA at birth significantly impacted survival only after 3 months of life.

Conclusions

The high morbidity and mortality in preterm and LBW neonates with CHD reflect their complexity and consequent limited treatment feasibility.

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.

Evaluation and Management of Noncardiac Comorbidities in Children With Congenital Heart Disease

Outcomes for patients with neonatal heart disease are affected by numerous noncardiac and genetic factors. These can include neonatal concerns, such as prematurity and low birth weight, and congenital anomalies, such as airway, pulmonary, gastrointestinal, and genitourinary anomalies, and genetic syndromes. This section will serve as a summary of these issues and how they may affect the evaluation and management of a neonate with heart disease. These noncardiac factors are heavily influenced by conditions common to neonatologists, making a strong argument for multidisciplinary care with neonatologists, cardiologists, surgeons, anesthesiologists, and cardiovascular intensivists. Through this section and this project, we aim to facilitate a comprehensive approach to the care of neonates with congenital heart disease.

Functional analysis of HECA variants identified in congenital heart disease in the Chinese population

Background

Congenital heart disease (CHD) is a class of cardiovascular defects that includes septal defects, outflow tract abnormalities, and valve defects. Human homolog of Drosophila headcase (HECA) is a novel cell cycle regulator whose role in CHD has not been elucidated. This is the first study to determine the frequency of HECA mutations in patients with CHD and the association between HECA variants and CHD.

Methods

In this study, we identified a candidate gene, HECA, by whole‐exome sequencing of an atrial septal defect family. To investigate the association between HECA variants and CHD risk, targeted exon sequencing was conducted in 689 individuals with sporadic CHD. We further analyzed the effect of HECA gene abnormalities on cardiomyocyte phenotype behavior and related signaling pathways by Western blotting, reverse transcription‐quantitative polymerase chain reaction, and scratch assay.

Results

We found a novel de novo mutation, c.409_410insA (p. W137fs), in the HECA gene and identified five rare deleterious variants that met the filtering criteria in 689 individuals with sporadic CHD. Fisher's exact test revealed a significant association between HECA variations and CHD compared with those in gnomADv2‐East Asians(p = 0.0027). Further functional analysis suggested that the variant p. W137fs resulted in a deficiency of the normal HECA protein, and HECA deficiency altered AC16 cell cycle progression, increased cell proliferation, and migration, and promoted the activation of the PDGF‐BB/PDGFRB/AKT pathway.

Conclusions

Our study identified HECA and its six rare variants, expanding the spectrum of genes associated with CHD pathogenesis in the Chinese population.

Mid-Term Outcomes of Heart Transplantation in Children with Genetic Disorders

BACKGROUND

Many congenital heart diseases (CHD) are associated with genetic defects. Children with complex CHD often develop heart failure, requiring heart transplant. Given the broad spectrum of genetic pathologies and dearth of transplants performed in these children, little is known regarding their outcomes.

METHODS

We conducted a retrospective review of heart transplants performed at a high-volume center from 2007-2021. Patients were separated into pathogenic molecular and copy number variants, aneuploidies, and variants of uncertain significance, and compared to those without known genetic diagnoses. Variables included genetic diagnoses, bridge-to-transplant approach, preoperative comorbidities, operative characteristics, and postoperative complications. Outcomes included ICU-free days to 28 days, hospital mortality, survival, rejection, re-transplantation, and educational status at latest follow-up.

RESULTS

223 patients were transplanted over the study period: 9.9% (22/223) had pathogenic molecular variants, 4.5% (10/223) had copy number variants, 1.8% (4/223) had aneuploidies, and 9.0% (20/223) had variants of uncertain significance. The most common anomalies were Turner syndrome (n=3) and 22q11.2 deletion syndrome (n=2). Children with aneuploidies had higher rates of hepatic dysfunction and hypothyroidism, while those with pathogenic copy number variants had higher rates of preoperative gastrostomy and stroke. Children with aneuploidies were intubated longer post-transplant, with greater need for re-intubation, and had the fewest ICU-free days. Mortality and mean survival did not differ. At median follow-up of 4.4 (1.9-8.8) years, 89.7% (26/29) of survivors with pathogenic anomalies were attending or had graduated school.

CONCLUSIONS

Despite more preoperative comorbidities, mid-term outcomes following heart transplant in children with genetic syndromes and disorders are promising.

Estimating the frequency of causal genetic variants in foetuses with congenital heart defects: a Chinese cohort study

BACKGROUND

The belief that genetics plays a major role in the pathogenesis of congenital heart defects (CHD) has grown popular among clinicians. Although some studies have focused on the genetic testing of foetuses with CHD in China, the genotype-phenotype relationship has not yet been fully established, and hotspot copy number variations (CNVs) related to CHD in the Chinese population are still unclear. This cohort study aimed to assess the prevalence of chromosomal abnormalities in Chinese foetuses with different types of CHD.

RESULTS

In a cohort of 200 foetuses, chromosomal abnormalities were detected in 49 (24.5%) after a prenatal chromosome microarray analysis (CMA), including 23 foetuses (11.5%) with aneuploidies and 26 (13.0%) with clinically significant CNVs. The additional diagnostic yield following whole exome sequencing (WES) was 11.5% (6/52). The incidence of total chromosomal abnormality in the non-isolated CHD group (31.8%) was higher than that in the isolated CHD group (20.9%), mainly because the incidence of aneuploidy was significantly increased when CHD was combined with extracardiac structural abnormalities or soft markers. The chromosomal abnormality rate of the complex CHD group was higher than that of the simple CHD group; however, the difference was not statistically significant (31.8% vs. 23.6%, P = 0.398). The most common CNV detected in CHD foetuses was the 22q11.2 deletion, followed by deletions of 5p15.33p15.31, deletions of 15q13.2q13.3, deletions of 11q24.2q25, deletions of 17p13.3p13.2, and duplications of 17q12.

CONCLUSIONS

CMA is the recommended initial examination for cases of CHD in prenatal settings, for both simple heart defects and isolated heart defects. For cases with negative CMA results, the follow-up application of WES will offer a considerable proportion of additional detection of clinical significance.

Abnormal Microarray, Clinical Outcomes, and Surgical Risk Scores in Young Children with Cardiac Disease

The clinical implications of abnormal chromosomal microarray (CMA) remain unclear for children less than 1 year of age with critical heart disease. Our objective was to determine whether abnormal CMA was related to surgical severity scores or to pre-determined clinical outcomes, including cardiac arrest. Retrospective review of children under 1 year of age admitted to a pediatric cardiac intensive care unit from December, 2014 to September, 2017. Associations between CMA result and cardiac arrest, syndromic abnormalities, and extracardiac anomalies were evaluated. A simple and multivariable logistic regression model was used to analyze associations between STAT mortality category and CMA result. The overall prevalence of abnormal microarray was 48/168 (29%), with peak prevalence in AV septal defects and left-sided obstructive lesions. There was no statistical association between surgical severity scores and abnormal CMA (STAT 1/2 vs. 3+, odds ratio 0.56, p = 0.196). Abnormal CMA was associated with a higher prevalence of cardiac arrest (5/48 abnormal CMA vs. 2/120 normal CMA, p = 0.02). Abnormal CMA was associated with a higher frequency of syndromic abnormalities (18/48 abnormal CMA vs. 13/120 normal CMA, p < 0.001). There was a high prevalence of abnormal CMA findings in the pediatric cardiac population less than 1 year of age (29%), associated with cardiac arrest, but not associated with surgical risk score. The absence of a standardized protocol for ordering a CMA in the setting of congenital heart disease results in a highly variable prevalence data.

An update on the CHDGKB for the systematic understanding of risk factors associated with non-syndromic congenital heart disease

The Congenital Heart Disease Genetic Knowledge Base (CHDGKB) was established in 2020 to provide comprehensive knowledge about the genetics and pathogenesis of non-syndromic CHD (NS-CHD). In addition to the genetic causes of NS-CHD, environmental factors such as maternal drug use and gene-environment interactions can also lead to CHD. There is a need to integrate this information into a platform for clinicians and researchers to better understand the overall risk factors associated with NS-CHD. The updated CHDGKB contains the genetic and non-genetic risk factors from over 4200 records from PubMed that was manually curated to include the information associated with NS-CHD. The current version of CHDGKB, named CHD-RF-KB (KnowledgeBase for non-syndromic Congenital Heart Disease-associated Risk Factors), is an important tool that allows users to evaluate the recurrence risk and prognosis of NS-CHD, to guide treatment and highlight the precautions of NS-CHD. In this update, we performed extensive functional analyses of the genetic and non-genetic risk information in CHD-RF-KB. These data can be used to systematically understand the heterogeneous relationship between risk factors and NS-CHD phenotypes.

Clinical utility of fetal echocardiography: an Egyptian center experience

BACKGROUND

The impact of early diagnosis of fetal cardiac abnormalities on the postnatal outcome has been controversial in literature. We aimed to evaluate the role of fetal echocardiography (FE) as a diagnostic tool for early detection and proper management of fetal cardiac abnormalities, study the indications of referral and detect the perinatal outcome in our institution.

RESULTS

This is a cross-sectional observational and descriptive study that included one hundred and one singleton pregnant women (101 fetuses) who were referred for FE over a period of one year. Indications for referral and perinatal risk factors were documented. FE and postnatal transthoracic echocardiography were done. Fetal cardiac abnormalities were detected in 46.5% of cases. Congenital heart defects (CHDs) in 34.6%, fetal arrythmias in 9.9%, cardiomyopathy in 2.9% and cardiac mass (Rhabdomyoma) in 1% (combined structural and rhythm abnormalities were observed in two fetuses). Of the CHDs, complex heart lesions were diagnosed in 57.1%, common atrioventricular canal in 28.6% and conotrunchal anomalies in 14.3%. Of the ten cases with fetal arrythmias, five fetuses had tachyarrhythmias, four had ectopics and one fetus had congenital heart block in association with maternal lupus. The indications for referral were abnormal obstetric ultrasound (52.5%), maternal medical illnesses (23.8%), multiple neonatal deaths (13.9%) and positive family history of CHD (10.9%). The number of fetuses with cardiac abnormalities was significantly higher than those without cardiac abnormalities in mothers not exposed to perinatal risk factors (p = 0.009) and was statistically lower in mothers exposed to perinatal risk factors (p = 0.005). FE showed 100% accuracy in diagnosing complex lesions, common atrio-ventricular canals, cono-truncal anomalies, cardiac masses and fetal arrhythmias. It missed two cases of tiny muscular ventricular septal defects and one case of aortic coarctation. Cases of fetal supraventricular tachycardia were successfully treated in-utero.

CONCLUSIONS

CHDs exist in fetuses with no underlying perinatal risk factors. FE can accurately diagnose most of the cardiac anomalies though few errors remain challenging (aortic coarctation). It also offers a good chance for successful early life-saving management of some types of fetal arrhythmia.

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.

Prevalence of associated extracardiac anomalies in prenatally diagnosed congenital heart diseases

Objective

To investigate the prevalence of extracardiac anomalies (ECA) in prenatally diagnosed congenital heart diseases (CHD), and to provide more information for counseling of women with prenatally diagnosed fetal CHD.

Methods

This was a retrospective cohort study of 791 cases of fetal CHD diagnosed by prenatal ultrasound from January 2005 to April 2018. Associated ECAs included extracardiac structural malformation (ECM), chromosomal anomaly, and 22q11.2 microdeletion. CHD was classified into 10 groups according to a modified anatomic and clinical classification of congenital heart defects.

Results

The overall prevalence of ECA in our CHD cohort was 28.6% (226/791): ECM, 25.3%; chromosomal anomaly, 11.7%; and 22q11.2 microdeletion, 5.5%. For those with ECM, ventricular septal defect (VSD) had the highest prevalence (34.5%), followed by anomalies of atrioventricular junctions and valves (28.8%) and heterotaxy (26.9%). For those with chromosomal anomaly, anomalies of atrioventricular junctions and valves had the highest prevalence (37.5%), followed by anomalies of atria and interatrial communications (25.0%) and VSD (22.9%). 22q11.2 microdeletion was detected only in those with anomalies of extrapericardial arterial trunks (14.3%) or ventricular outflow tracts (6.4%).

Conclusion

ECM, chromosomal anomaly, and 22q11.2 microdeletion have different prevalence according to the type of CHD.

The Role of Epigenetics in Congenital Heart Disease

Congenital heart disease (CHD) is the most common birth defect among newborns worldwide and contributes to significant infant morbidity and mortality. Owing to major advances in medical and surgical management, as well as improved prenatal diagnosis, the outcomes for these children with CHD have improved tremendously so much so that there are now more adults living with CHD than children. Advances in genomic technologies have discovered the genetic causes of a significant fraction of CHD, while at the same time pointing to remarkable complexity in CHD genetics. For this reason, the complex process of cardiogenesis, which is governed by multiple interlinked and dose-dependent pathways, is a well investigated process. In addition to the sequence of the genome, the contribution of epigenetics to cardiogenesis is increasingly recognized. Significant progress has been made dissecting the epigenome of the heart and identified associations with cardiovascular diseases. The role of epigenetic regulation in cardiac development/cardiogenesis, using tissue and animal models, has been well reviewed. Here, we curate the current literature based on studies in humans, which have revealed associated and/or causative epigenetic factors implicated in CHD. We sought to summarize the current knowledge on the functional role of epigenetics in cardiogenesis as well as in distinct CHDs, with an aim to provide scientists and clinicians an overview of the abnormal cardiogenic pathways affected by epigenetic mechanisms, for a better understanding of their impact on the developing fetal heart, particularly for readers interested in CHD research.

Genetic considerations for adults with congenital heart disease

Congenital heart disease (CHD) remains the most common birth defect, with an estimated incidence of approximately 1% of all births. The population of adults with CHD is growing rapidly with advances in medical care. Overall survival to adulthood in the current era estimated to exceed 90%. Genetic causes of CHD can be classified into several broad categories: (a) chromosomal aneuploidy, (b) large chromosomal deletion or duplication, (c) single gene mutation, and (d) copy number variation. However, only 20-30% of CHD cases have an established etiology characterized by either genetic abnormalities or environmental factors. The role of genetics in the field of adult CHD is only increasing. More adult patients with CHD are seeking genetic counseling to understand the etiology of their underlying CHD and the risks to future offspring. A multidisciplinary approach is essential to provide appropriate counseling to patients regarding indications for genetic testing and interpretations of results. Novel advances with precision medicine may soon enable clinicians to individualize therapies for a comprehensive approach to the care of adult patients with CHD.

The Current Landscape of Genetic Testing in Cardiovascular Malformations: Opportunities and Challenges

Human cardiovascular malformations (CVMs) frequently have a genetic contribution. Through the application of novel technologies, such as next-generation sequencing, DNA sequence variants associated with CVMs are being identified at a rapid pace. While clinicians are now able to offer testing with NGS gene panels or whole exome sequencing to any patient with a CVM, the interpretation of genetic variation remains problematic. Variable phenotypic expression, reduced penetrance, inconsistent phenotyping methods, and the lack of high-throughput functional testing of variants contribute to these challenges. This article elaborates critical issues that impact the decision to broadly implement clinical molecular genetic testing in CVMs. Major benefits of testing include establishing a genetic diagnosis, facilitating cost-effective screening of family members who may have subclinical disease, predicting recurrence risk in offsprings, enabling early diagnosis and anticipatory management of CV and non-CV disease phenotypes, predicting long-term outcomes, and facilitating the development of novel therapies aimed at disease improvement or prevention. Limitations include financial cost, psychosocial cost, and ambiguity of interpretation of results. Multiplex families and patients with syndromic features are two groups where disease causation could potentially be firmly established. However, these account for the minority of the overall CVM population, and there is increasing recognition that genotypes previously associated with syndromes also exist in patients who lack non-CV findings. In all circumstances, ongoing dialog between cardiologists and clinical geneticists will be needed to accurately interpret genetic testing and improve these patients’ health. This may be most effectively implemented by the creation and support of CV genetics services at centers committed to pursuing testing for patients.

Prevalence of Noncardiac and Genetic Abnormalities in Neonates Undergoing Cardiac Operations: Analysis of The Society of Thoracic Surgeons Congenital Heart Surgery Database

BACKGROUND

Among patients with congenital heart disease (CHD), the coexistence of noncardiac congenital anatomic abnormalities (NC), genetic abnormalities (GA), and syndromes (S) may influence therapeutic strategies and outcomes. The appreciated prevalence of these abnormalities has risen because increased screening and improved diagnostic precision enable identification of these comorbidities in a larger fraction of neonates with CHD. We examined the contemporary prevalence and distribution of NC/GA/S across diagnostic groups among neonates undergoing cardiac operations using a large nationally representative clinical registry.

METHODS

The Society of Thoracic Surgeons Congenital Heart Surgery Database (STS-CHSD) was queried to identify neonates (≤30 days) who underwent index cardiac operations from 2010 to 2013. The fundamental cardiac diagnosis was used to identify 10 diagnostic groups. The prevalence of NC/GA/S was reported across each group.

RESULTS

The cohort included 15,376 index neonatal operations from 112 centers. Overall, 18.8% (2,894 of 15,376) of operations were performed in neonates with NC/GA/S. Patients with atrioventricular septal defect (212 of 357 [59.4%]), interrupted aortic arch (248 of 567 [43.7%]), truncus arteriosus (204 of 554 [36.8%]), and tetralogy of Fallot (417 of 1,383 [30.2%]) had the highest prevalence of NC/GA/S abnormalities, whereas those with transposition of the great arteries (111 of 2,778 [4.0%]) had the lowest prevalence. The most commonly identified NC/GA/S included heterotaxy (597 of 15,376 [3.9%]), DiGeorge syndrome or 22q11 deletion (550 of 15,376 [3.6%]), Down syndrome or trisomy 21 (318 of 15, 376 [2.1%]), intestinal malrotation (220 of 15,376 [1.4%]), and Turner syndrome or 45XO (189 of 15,376 [1.2%]).

CONCLUSIONS

The prevalence of NC/GA/S varies widely across CHD diagnostic groups. This information may be useful for patient counseling, recommendations for screening for anomalies and genetic disorders, and perioperative management.

Genetic Evaluation and Use of Chromosome Microarray in Patients with Isolated Heart Defects: Benefits and Challenges of a New Model in Cardiovascular Care

Congenital heart defects (CHDs) are common birth defects and result in significant morbidity and global economic impact. Genetic factors play a role in most CHDs; however, identification of these factors has been historically slow due to technological limitations and incomplete understanding of the impact of human genomic variation on normal and abnormal cardiovascular development. The advent of chromosome microarray (CMA) brought tremendous gains in identifying chromosome abnormalities in a variety of human disorders and is now considered part of a standard evaluation for individuals with multiple congenital anomalies and/or neurodevelopmental disorders. Several studies investigating use of CMA found that this technology can identify pathogenic copy-number variations (CNVs) in up to 15-20% of patients with CHDs with other congenital anomalies. However, there have been fewer studies exploring the use of CMA for patients with isolated CHDs. Recent studies have shown that the diagnostic yield of CMA in individuals with seemingly isolated CHD is lower than in individuals with CHDs and additional anomalies. Nevertheless, positive CMA testing in this group supports chromosome variation as one mechanism underlying the development of isolated, non-syndromic CHD - either as a causative or risk-influencing genetic factor. CMA has also identified novel genomic variation in CHDs, shedding light on candidate genes and pathways involved in cardiac development and malformations. Additional studies are needed to further address this issue. Early genetic diagnosis can enhance the medical management of patients and potentially provide crucial information about recurrence. This information is critical for genetic counseling of patients and family members. In this review, we review CMA for the non-genetics cardiology provider, offer a summary of CNV in isolated CHDs, and advocate for the use of CMA as part of the cardiovascular genetics evaluation of patients with isolated CHDs. We also provide perspective regarding the benefits and challenges that lie ahead for this model in the clinical setting.

Perinatal outcome of congenital heart disease in a population with high consanguinity

OBJECTIVE

To report the perinatal pattern and outcome of fetuses with congenital heart disease (CHD) in consanguineous marriages.

METHODS

Retrospective chart review was performed for fetuses undergoing fetal echocardiography (FE) in our institution. The primary outcome was survival at 28 days after birth.

RESULTS

Between 1 January 2005 and 31 December 2010, 1950 pregnant women carrying 2151 fetuses underwent a total of 2828 FEs. CHD was diagnosed in 152 fetuses (7.1%), and perinatal outcome was available in 120, among which 78 (65%) had consanguineous parents. Thirteen fetuses died in utero, while 86 (71.7%) survived. The most prevalent lesions included left heart obstruction (25.8%), conotruncal malformations (21.7%), septal defects (18.3%), and cardiomyopathy (15.8%). Correct diagnosis was achieved in 92.2% of the cases. Extracardiac malformations occurred in 48.3% of the fetuses and were associated with increased mortality regardless of the type of CHD (P<0.001, odds ratio 6.8, 95% confidence interval 2.7-17.5).

CONCLUSION

Joint FE clinics detect most CHD with high accuracy. Consanguinity contributes to a higher prevalence of fetal cardiac and non-cardiac malformations. The presence of extracardiac anomalies is associated with an increase in perinatal mortality.

Prenatal Diagnosis of DNA Copy Number Variations by Genomic Single-Nucleotide Polymorphism Array in Fetuses with Congenital Heart Defects

Objectives: To evaluate the usefulness of single-nucleotide polymorphism (SNP) array for prenatal genetic diagnosis of congenital heart defect (CHD), we used this approach to detect clinically significant copy number variants (CNVs) in fetuses with CHDs. Methods: A HumanCytoSNP-12 array was used to detect genomic samples obtained from 39 fetuses that exhibited cardiovascular abnormalities on ultrasound and had a normal karyotype. The relationship between CNVs and CHDs was identified by using genotype-phenotype comparisons and searching of chromosomal databases. All clinically significant CNVs were confirmed by real-time PCR. Results: CNVs were detected in 38/39 (97.4%) fetuses: variants of unknown significance were detected in 2/39 (5.1%), and clinically significant CNVs were identified in 7/39 (17.9%). In 3 of the 7 fetuses with clinically significant CNVs, 3 rare and previously undescribed CNVs were detected, and these CNVs encompassed the CHD candidate genes FLNA (Xq28 dup), BCOR (Xp11.4 dup), and RBL2 (16q12.2 del). Conclusion: Compared with conventional cytogenetic genomics, SNP array analysis provides significantly improved detection of submicroscopic genomic aberrations in pregnancies with CHDs. Based on these results, we propose that genomic SNP array is an effective method which could be used in the prenatal diagnostic test to assist genetic counseling for pregnancies with CHDs.

Genetics and genetic testing in congenital heart disease

Congenital heart defects (CHDs) are structural abnormalities of the heart and great vessels that are present from birth. The presence or absence of extracardiac anomalies has historically been used to identify patients with possible monogenic, chromosomal, or teratogenic CHD causes. These distinctions remain clinically relevant, but it is increasingly clear that nonsyndromic CHDs can also be genetic. This article discusses key morphologic, molecular, and signaling mechanisms relevant to heart development, summarizes overall progress in molecular genetic analyses of CHDs, and provides current recommendations for clinical application of genetic testing.

Pattern of congenital heart diseases in Rwandan children with genetic defects

INTRODUCTION

Congenital heart diseases (CHD) are commonly associated with genetic defects. Our study aimed at determining the occurrence and pattern of CHD association with genetic defects among pediatric patients in Rwanda.

METHODS

A total of 125 patients with clinical features suggestive of genetic defects were recruited. Echocardiography and standard karyotype studies were performed in all patients.

RESULTS

CHDs were detected in the majority of patients with genetic defects. The commonest isolated CHD was ventricular septal defect found in many cases of Down syndrome. In total, chromosomal abnormalities represented the majority of cases in our cohort and were associated with various types of CHDs.

CONCLUSION

Our findings showed that CHDs are common in Rwandan pediatric patients with genetic defects. These results suggest that a routine echocardiography assessment combined with systematic genetic investigations including standard karyotype should be mandatory in patients presenting characteristic clinical features in whom CHD is suspected to be associated with genetic defect.

Congenital heart defects and extracardiac malformations

OBJECTIVE

To review the association between congenital heart defects and extracardiac malformations.

DATA SOURCES

Scientific articles were searched in the Medline, Lilacs, and SciELO databases, using the descriptors "congenital heart disease," "congenital heart defects," "congenital cardiac malformations," "extracardiac defects," and "extracardiac malformations." All case series that specifically explored the association between congenital heart defects and extracardiac malformations were included.

DATA SYNTHESIS

Congenital heart diseases are responsible for about 40% of birth defects, being one of the most common and severe malformations. Extracardiac malformations are observed in 7 to 50% of the patients with congenital heart disease, bringing a greater risk of comorbidity and mortality and increasing the risks related to heart surgery. Different studies have attempted to assess the presence of extracardiac abnormalities in patients with congenital heart disease. Among the changes described, those of the urinary tract are more often reported. However, no study has evaluated all patients in the same way.

CONCLUSIONS

Extracardiac abnormalities are frequent among patients with congenital heart disease, and patients with these alterations may present an increased risk of morbimortality. Therefore, some authors have been discussing the importance and cost-effectiveness of screening these children for other malformations by complementary exams.

Outcome and requirement for surgical repair following prenatal diagnosis of ventricular septal defect

OBJECTIVE

To document outcome following prenatal diagnosis of ventricular septal defects (VSDs), particularly associated anomalies and the requirement for surgical closure of the defect.

METHODS

All cases of prenatal diagnosis of a VSD made by fetal cardiologists at a tertiary fetal medicine referral center in the period January 2002 to December 2011 were extracted from our database. Data regarding fetal cardiac diagnosis, extracardiac anomalies, nuchal translucency thickness and karyotype were noted.

RESULTS

A total of 171 cases fulfilled our selection criteria. Of these, 69% were diagnosed with a perimembranous VSD and 31% with a muscular defect. The median gestational age at diagnosis was 21 + 6 (range, 12 + 0 to 37 + 3) weeks. Owing to severe extracardiac or genetic conditions, pregnancy resulted in intrauterine death or termination in 49% cases, and postnatal death occurred in 9% of cases. Seventy-two babies were liveborn, and were regarded as potential surgical candidates if hemodynamics suggested that surgery was indicated. Surgical closure of the VSD proved necessary in 50% of the patients with a perimembranous VSD and 13% of those with a muscular VSD. All patients operated on survived surgical repair. No karyotypic abnormalities were identified in fetuses with VSDs that had normal first-trimester screening and no other sonographic abnormalities.

CONCLUSIONS

A high proportion of VSDs diagnosed during fetal life (29%) require postnatal surgical intervention. The assessment of hemodynamic significance from fetal echocardiography is imperfect. The presence of extracardiac abnormalities or abnormal results on first-trimester screening has a major impact on the incidence of karyotypic abnormalities in affected fetuses. This should inform discussions with parents about invasive testing.

What do we know about cognitive functioning in adult congenital heart disease?

With the advent of improved medical and surgical care in congenital heart disease, there has been an increase in the number of patients who survive into adulthood, giving rise to a new patient population 'Adults with congenital heart disease'. In the past, morbidity and mortality were the primary concerns for this group. However, with improvements in outcome attention has shifted to other factors such as psychosocial and cognitive functioning. This paper reviews the literature on the cognitive functioning in adult congenital heart disease patients. A total of five relevant articles were retrieved via electronic searches of six databases, including MEDLINE, EMBASE, CINAHL, AMED, PsychINFO, and PubMed. The results displayed a consensus on the presence of some cognitive difficulties in adult congenital heart disease patients. The aetiology of cognitive dysfunctions appears to be multifactorial. The literature is limited by the very small number of studies looking at adults with congenital heart disease, with the majority focusing on cognitive functioning among children with congenital heart disease. However, the presence of cognitive dysfunctions and the resulting impact on the patient's day to day lives warrant for a more detailed and prospective research to enhance the understanding of its aetiology and impact.

Of mice and men: molecular genetics of congenital heart disease

Congenital heart disease (CHD) affects nearly 1 % of the population. It is a complex disease, which may be caused by multiple genetic and environmental factors. Studies in human genetics have led to the identification of more than 50 human genes, involved in isolated CHD or genetic syndromes, where CHD is part of the phenotype. Furthermore, mapping of genomic copy number variants and exome sequencing of CHD patients have led to the identification of a large number of candidate disease genes. Experiments in animal models, particularly in mice, have been used to verify human disease genes and to gain further insight into the molecular pathology behind CHD. The picture emerging from these studies suggest that genetic lesions associated with CHD affect a broad range of cellular signaling components, from ligands and receptors, across down-stream effector molecules to transcription factors and co-factors, including chromatin modifiers.

Rapid detection of aneuploidy and unbalanced chromosomal rearrangements by subtelomeric multiplex ligation-dependent probe amplification in fetuses with congenital heart disease

OBJECTIVE

To validate multiplex ligation-dependent probe amplification (MLPA) with subtelomeric probe mixes as a tool for diagnosis of aneuploidy and unbalanced terminal chromosomal rearrangements in fetuses with congenital heart disease.

METHODS

A prospective study of 117 fetuses found to have structural heart defects by ultrasound at 17-40 weeks' gestation. MLPA with P036E and P070B probe mixes was performed and compared to traditional karyotyping by cell culture and to findings of quantitative fluorescence-polymerase chain reaction (QF-PCR).

RESULTS

MLPA was able to define the fetal karyotype in 99% of cases whereas cell culture only defined the karyotype in 64% of cases. Consequently, the overall number of chromosomal abnormalities that were detected increased. The majority of these affected chromosomes, 21, 18, 13, X or Y, were also confirmed by QF-PCR. Two (5%) cases had atypical aneuploidy that was confirmed by MLPA but not by QF-PCR. In 4 cases, structural rearrangements or mosaicism were not detected by MLPA.

CONCLUSIONS

Subtelomeric MLPA may be a valuable adjunct to QF-PCR and/or conventional cytogenetics for the investigation of chromosomal abnormalities in fetuses with congenital heart disease.

Critical congenital heart disease--utility of routine screening for chromosomal and other extracardiac malformations

Objective.  Infants with critical congenital heart disease (CHD) can have genetic and other extracardiac malformations, which add to the short- and long-term risk of morbidity and perhaps mortality. We sought to examine our center's practice of screening for extracardiac anomalies and to determine the yield of these tests among specific cardiac diagnostic categories. Design.  Retrospective review of infants admitted to the cardiac intensive care unit with a new diagnosis of CHD. Subjects were categorized into six groups: septal defects (SD), conotruncal defects (CTD), single-ventricle physiology (SV), left-sided obstructive lesions (LSO), right-sided obstructive lesions (RSO), and "other" (anomalous pulmonary venous return, Ebstein's anomaly). Screening modalities included genetic testing (karyotype and fluorescent in situ hybridization for 22q11.2 deletion), renal ultrasound (RUS), and head ultrasound (HUS). Results.  One hundred forty-one patients were identified. The incidence of cardiac anomalies was: CTD (36%), SD (18%), SV (18%), LSO (14%), RSO (3%), and "other" (8%). Overall 14% had an abnormal karyotype, 5% had a deletion for 22q11.2, 28% had an abnormal RUS and 22% had abnormal HUS. Patients in SD and SV had the highest incidence of abnormal karyotype (36% and 17%); 22q11.2 deletion was present only in CTD and LSO groups (9% and 7%, respectively); abnormal RUS and HUS were seen relatively uniformly in all categories. Premature infants had significantly higher incidence of renal 43% vs. 24%, and intracranial abnormalities 46% vs. 16%. Conclusion.  Infants with critical CHD and particularly premature infants have high incidence of genetic and other extracardiac anomalies. Universal screening for these abnormalities with ultrasonographic and genetic testing maybe warranted because early detection could impact short and long-term outcomes.

Congenital heart defects and major structural noncardiac anomalies, Atlanta, Georgia, 1968 to 2005

OBJECTIVE

To identify the proportion of major structural noncardiac anomalies identified with congenital heart defects (CHDs).

STUDY DESIGN

Records of infants with CHDs in the Metropolitan Atlanta Congenital Defects Program who were born during the period 1968 through 2005 were classified as having isolated, syndromic, multiple CHD (ie, having an unrecognized pattern of multiple congenital anomalies or a recognized pattern of multiple congenital anomalies of unknown etiology), or laterality defects. Frequencies of associated noncardiac anomalies were obtained.

RESULTS

We identified 7984 live-born and stillborn infants and fetuses with CHDs. Among them, 5695 (71.3%) had isolated, 1080 (13.5%) had multiple, 1048 (13.1%) had syndromic, and 161 (2.0%) had laterality defects. The percentage of multiple congenital anomalies was highest for case with atrial septal defects (18.5%), cardiac looping defects (17.2%), and conotruncal defects (16.0%), and cases with atrioventricular septal defects represented the highest percentages of those with syndromic CHDs (66.7%).

CONCLUSIONS

Including those with syndromes and laterality defects, 28.7% of case infants with CHDs had associated major noncardiac malformations. Thus, infants with CHDs warrant careful examination for the presence of noncardiac anomalies.

Array comparative genomic hybridization as a diagnostic tool for syndromic heart defects

OBJECTIVES

To investigate different aspects of the introduction of array comparative genomic hybridization (aCGH) in clinical practice.

STUDY DESIGN

A total 150 patients with a syndromic congenital heart defect (CHD) of unknown cause were analyzed with aCGH at 1-Mb resolution. Twenty-nine of these patients, with normal results on 1Mb aCGH, underwent re-analysis with 244-K oligo-microarray. With a logistic regression model, we assessed the predictive value of patient characteristics for causal imbalance detection. On the basis of our earlier experience and the literature, we constructed an algorithm to evaluate the causality of copy number variants.

RESULTS

With 1-Mb aCGH, we detected 43 structural variants not listed as clinically neutral polymorphisms, 26 of which were considered to be causal. A systematic comparison of the clinical features of these 26 patients to the remaining 124 patients revealed dysmorphism as the only feature with a significant predictive value for reaching a diagnosis with 1-Mb aCGH. With higher resolution analysis in 29 patients, 75 variants not listed as clinically neutral polymorphisms were detected, 2 of which were considered to be causal.

CONCLUSIONS

Molecular karyotyping yields an etiological diagnosis in at least 18% of patients with a syndromic CHD. Higher resolution evaluation results in an increasing number of variants of unknown significance.

Embryonic heart rate as a prognostic factor for chromosomal abnormalities

OBJECTIVE

The purpose of this study was to evaluate the role of a slow embryonic heart rate in embryos before 7 weeks' gestation as a marker in screening for chromosomal abnormalities.

METHODS

Fifty-seven embryos before 7 weeks' gestation with slow heart rates were compared with 1156 embryos of the same gestational period with normal heart rates. Embryos that showed an increased risk of chromosomal abnormalities in the screening blood tests underwent invasive analysis for abnormal karyotype detection.

RESULTS

The rates of first-trimester death were 15.8% for pregnancies with slow embryonic heart rates (9 of 57) and 2.5% for those with normal heart rates (29 of 1156). Because of the increased risk of chromosomal abnormalities, amniocentesis was performed on 6 with slow embryonic heart rates and 61 with normal embryonic heart rates. After karyotype analysis, there were 2 fetuses with trisomy 21 in each group, which represented significantly higher percentage of embryos with trisomy 21 in the slow-heart rate group compared with the normal-heart rate group (P < .05).

CONCLUSIONS

When a slow embryonic heart rate is detected before 7 weeks' gestation, there is a higher likelihood of chromosomal abnormalities.

Universal screening for extracardiac abnormalities in neonates with congenital heart disease

Extracardiac or genetic abnormalities (EGA) represent a factor in the morbidity of patients with congenital heart disease. We evaluated the way neonates with CHD are screened at our institution and determined the yield for the screening tests. We reviewed the charts of 223 neonates with structural CHD. Subjects were categorized into 6 groups: univentricular, left-sided obstructive lesions, right-sided obstructive lesions, septal defects, conotruncal defects (CTD), and other. We reviewed which patients underwent cranial ultrasonogram (CUS), abdominal ultrasonogram (AUS), and/or genetic studies (GS) as well as their results. There was a high prevalence of EGA in each group by CUS (32% to 42%), AUS (32% to 69%), and GS (10% to 60%). There was considerable variability in the proportion within each group that underwent screening tests, and the consistency of screening often was not congruent with the likelihood of abnormal results. Approximately 50% of our patients had >/=1 EGA identified, resulting in a cost-yield ratio of $4,508/patient with EGA. Screening for EGA at our institution is not uniform and is often at odds with the prevalence of such patients. Given the high prevalence of EGA, we advocate for a universal screening program for neonates with CHD using cranial/abdominal ultrasonography and genetic testing.

Cardiac findings in fetal and pediatric autopsies: a five-year retrospective review

This review aims to determine the spectrum of cardiac findings in our fetal and pediatric postmortem population and provide an analysis of associated extracardiac malformations and genetic abnormalities. Pediatric autopsy reports from 2003 to 2007 inclusive were reviewed and cases with cardiac pathology selected for analysis. Over the 5-year period, 119 cases (10.8%) with abnormal cardiac findings were identified from a total of 1102 postmortem examinations. Of these cardiac cases, 42% were after termination of pregnancy for fetal anomaly, 29% after fetal demise, 14% after neonatal unit death, 3% after hospital inpatient death, and 11% after sudden unexpected death. Structural abnormality cases numbered 107 (90%), with ventricular septal defect as the most common individual defect. Nonstructural abnormality cases, such as myocarditis, numbered 12 (10%). Extracardiac malformations were identified in 78%. Chromosome or gene aberrations were detected in 37%. This review highlights the potential benefit of introducing routine fetal anomaly scanning, the need for cardiac pathology training for pediatric pathologists, and the importance of examination of the heart and associated vessels in all cases to provide parents with as much information as possible and aid identification of the etiology and associations of cardiac pathology.

Descriptive epidemiology of congenital heart disease in Northern England

Congenital heart disease (CHD) is the most prevalent group of congenital anomalies. There is considerable variation in the reported epidemiology of CHD, mainly attributable to methodological differences. Using register-based data, the current study describes the epidemiology of CHD in a geographically well-defined population of the North of England during 1985-2003. The total prevalence of CHD was 85.9 per 10 000 births and terminations of pregnancy for fetal anomaly. Livebirth prevalence was 79.7 per 10 000 livebirths. Both total and livebirth prevalence increased during the study period. Ninety-two per cent of affected pregnancies resulted in a livebirth, 5% were terminated, 2% resulted in a stillbirth, and 1% in a late miscarriage. Almost a quarter (23%) of cases had one or more coincident anomalies of other organs, with chromosomal abnormalities the most frequent group. A total of 89.2% of cases survived to 1 year and the survival improved during the study period. This population-based study has demonstrated an increasing trend in both prevalence and survival among children with CHD.

Critical heart defects--the diagnostic challenge

Infants with potentially life threatening congenital heart defects (CHDs) are discharged from hospital after birth with the condition unrecognized. Improved prenatal ultrasound imaging and universal pulse oximetry screening of babies in nurseries are strategies that probably most would contribute to avoid such defects to be missed.

CONCLUSION

In general combining first day of life pulse oximetry, clinical examination and echocardiography before discharge in suspect cases is a rational strategy for early postnatal detection of heart defects. Universal echocardiography screening of newborns may be too resource consuming to be cost-effective.