Non-syndromic Congenital Heart Defects Research Articles

Speech Sounds Production, Narrative Skills, and Verbal Memory of Children with 22q11.2 Microdeletion.

22q11.2 deletion syndrome (22q11.2DS), the most frequent microdeletion syndrome in humans, is related to a high risk of developing neurodevelopmental disorders. About 95% of patients with 22q11.2DS have speech and language impairments. Global articulation, story generation, and verbal memory tests were applied to compare articulatory characteristics of speech sounds, spontaneous language abilities, and immediate verbal memory between four groups of Serbian-speaking children: patients with 22q11.2DS, children with clinical presentation of 22q11.2DS that do not have the microdeletion, children with non-syndromic congenital heart defects, and their peers with typical speech-sound development. The obtained results showed that children with this microdeletion have impaired articulation skills and expressive language abilities. However, we did not observe weaker receptive language skills and immediate verbal memory compared to healthy controls. Children with 22q11.2DS should be considered a risk category for the development of speech-sound pathology and expressive language abilities. Since speech intelligibility is an instrument of cognition and adequate peer socialization, and language impairment in school-aged children with 22q11DS might be an indicator of increased risk for later psychotic symptoms, patients with 22q11.2 microdeletion should be included in a program of early stimulation of speech-language development immediately after diagnosis is established.

Use of polygenic and clinical risk scores in wide spectrum congenital heart malformations: a diagnostic and therapeutic perspective

Worldwide, congenital heart defects (CHDs) are a leading cause of mortality and morbidity. Globally, the annual prevalence rate of CHDs is about 1.5 million. It is one of the most common life-threatening congenital malformations, with a visible difference between high-income countries (HICs) and developing countries. This difference may be attributed to the diagnostic facilities and interventions.1 Moreover, the use of genetic and clinical risk scores is less studied in this field compared to other diagnostic and therapeutic approaches. Thus, we comprehensively review the available literature on adult and pediatric syndromic or non-syndromic CHDs and propose limitations and future directions in this field. Risk factors for this fatal disease include genetic and environmental factors.2,3 Risk stratification based on prenatal diagnosis with genetic counseling has shown better clinical outcomes. The modified World Health Organization (mWHO) guidelines are among the first proposed for risk stratification based on clinical scores.4 The combination of polygenic risk scores (PRS) and clinical risk evaluation has been adopted in various populations as better diagnostic and therapeutic approaches for various diseases, including coronary artery disease,5 diabetes,6 obesity,7 and cancers.8,9 However, unlike these diseases, polygenic risk scores are rarely used for the genetic diagnosis of CHD patients. The clinical utility of polygenic risk scores for CHDs is still in the early stages and requires validation studies in different cohorts. Incorporating PRS into the clinical setting may improve CHD diagnosis and therapeutic strategies.10 Recently, an initial attempt was made to determine the clinical utility of polygenic risk scores in a large dataset of the European cohort. Data from this study suggested a high potential for PRS in distinguishing between clinical phenotypes (mild, moderate, and severe) of congenital heart malformations.11 Furthermore, this hypothesis was tested in patients with transposition of the great arteries (TGA) to assess the utility of risk stratification after arterial switch operation. The cumulative risk score was computed for single nucleotide polymorphisms (SNPs) that reached the threshold statistical significance of p<1×10−5 in the initial analysis. Combined clinical and polygenic risk scores showed improved risk stratification in mild, moderate, and severe TGA phenotypes.12 Similarly, in another European cohort, the risk allele frequency was higher in the diseased group compared to the control group. However, statistical analysis suggested a non-significant association with p>0.05. Interestingly, combined risk scores constructed for selected SNPs showed a significant association with the disease with a p-value of 0.002. This evidence further supports the hypothesis that the cumulative effect of polymorphisms has better diagnostic and therapeutic efficacy than individual SNPs.13 There are certain limitations to its clinical use. Firstly, social stigma and lack of awareness regarding this disease are major hurdles. Secondly, there is a need to recruit a large number of samples from different populations to validate the clinical utility of PRS. Additionally, a lack of resources in developing countries also contributes to fatal outcomes. We recommend conducting large cohort studies in different ethnic groups to predict better risk associations, develop better therapeutic strategies, and formulate management guidelines.

A gene-based association test of interactions for maternal-fetal genotypes identifies genes associated with nonsyndromic congenital heart defects.

The risk of congenital heart defects (CHDs) may be influenced by maternal genes, fetal genes, and their interactions. Existing methods commonly test the effects of maternal and fetal variants one-at-a-time and may have reduced statistical power to detect genetic variants with low minor allele frequencies. In this article, we propose a gene-based association test of interactions for maternal-fetal genotypes (GATI-MFG) using a case-mother and control-mother design. GATI-MFG can integrate the effects of multiple variants within a gene or genomic region and evaluate the joint effect of maternal and fetal genotypes while allowing for their interactions. In simulation studies, GATI-MFG had improved statistical power over alternative methods, such as the single-variant test and functional data analysis (FDA) under various disease scenarios. We further applied GATI-MFG to a two-phase genome-wide association study of CHDs for the testing of both common variants and rare variants using 947 CHD case mother-infant pairs and 1306 control mother-infant pairs from the National Birth Defects Prevention Study (NBDPS). After Bonferroni adjustment for 23,035 genes, two genes on chromosome 17, TMEM107 (p = 1.64e-06) and CTC1 (p = 2.0e-06), were identified for significant association with CHD in common variants analysis. Gene TMEM107 regulates ciliogenesis and ciliary protein composition and was found to be associated with heterotaxy. Gene CTC1 plays an essential role in protecting telomeres from degradation, which was suggested to be associated with cardiogenesis. Overall, GATI-MFG outperformed the single-variant test and FDA in the simulations, and the results of application to NBDPS samples are consistent with existing literature supporting the association of TMEM107 and CTC1 with CHDs.

CRELD1 variants are associated with bicuspid aortic valve in Turner syndrome

Turner syndrome (TS) is a chromosomal disorder caused by complete or partial loss of the second sex chromosome and exhibits phenotypic heterogeneity, even after accounting for mosaicism and karyotypic variation. Congenital heart defects (CHD) are found in up to 45 percent of girls with TS and span a phenotypic continuum of obstructive left-sided lesions, with bicuspid aortic valve (BAV) being the most common. Several recent studies have demonstrated a genome-wide impact of X chromosome haploinsufficiency, including global hypomethylation and altered RNA expression. The presence of such broad changes to the TS epigenome and transcriptome led others to hypothesize that X chromosome haploinsufficiency sensitizes the TS genome, and several studies have demonstrated that a second genetic hit can modify disease susceptibility in TS. The objective of this study was to determine whether genetic variants in known heart developmental pathways act synergistically in this setting to increase the risk for CHD, specifically BAV, in TS. We analyzed 208 whole exomes from girls and women with TS and performed gene-based variant enrichment analysis and rare-variant association testing to identify variants associated with BAV in TS. Notably, rare variants in CRELD1 were significantly enriched in individuals with TS who had BAV compared to those with structurally normal hearts. CRELD1 is a protein that functions as a regulator of calcineurin/NFAT signaling, and rare variants in CRELD1 have been associated with both syndromic and non-syndromic CHD. This observation supports the hypothesis that genetic modifiers outside the X chromosome that lie in known heart development pathways may influence CHD risk in TS.

DNMT3B rs2424913 as a Risk Factor for Congenital Heart Defects in Down Syndrome

Impairments of the genes that encode enzymes that are involved in one-carbon metabolism because of the presence of gene polymorphisms can affect the methylation pattern. The altered methylation profiles of the genes involved in cardiogenesis may result in congenital heart defects (CHDs). The aim of this study was to investigate the association between the MTHFR rs1801133, MTHFR rs1801131, MTRR rs1801394, DNMT1 rs2228611, DNMT3A rs1550117, DNMT3B rs1569686, and DNMT3B rs2424913 gene polymorphisms and congenital heart defects in Down syndrome (DS) individuals. The study was conducted on 350 participants, including 134 DS individuals with CHDs (DSCHD+), 124 DS individuals without CHDs (DSCHD-), and 92 individuals with non-syndromic CHD. The genotyping was performed using the PCR-RFLP method. A statistically significant higher frequency of the DNMT3B rs2424913 TT in the DSCHD+ individuals was observed. The DNMT3B rs2424913 TT genotype, as well as the T allele, had significantly higher frequencies in the individuals with DS and atrial septal defects (ASDs) in comparison with the individuals with DS and other CHDs. Furthermore, our results indicate a statistically significant effect of the DNMT3B rs1569686 TT genotype in individuals with non-syndromic CHDs. The results of the study suggest that the DNMT3B rs2424913 TT genotypes may be a possible predisposing factor for CHDs in DS individuals, and especially those with ASDs.

Maternal age and the prevalence of congenital heart defects in Europe, 1995-2015: A register-based study.

Evidence on the direction and strength of association between maternal age and the prevalence of congenital heart defects (CHD) in different age group categories is conflicting. Some studies have illustrated different trends with an increase in prevalence in younger and older age groups while other studies have reported a linear relationship. Given the increase in maternal age over recent years, it is important to study the CHD prevalence by maternal age. To examine the association between maternal age and the prevalence of CHD in Europe between 1995 and 2015 using population-based data from 24 registries belonging to the European Surveillance of Congenital Anomalies (EUROCAT) network. Associations over time of all nonsyndromic CHD according to maternal age category and for three CHD severity groupings (severity group I: very severe; severity group II: severe; severity group III: less severe) were examined using Bayesian multilevel Poisson regression modeling. Further subgroup analyses were undertaken within four maternal age-bands: ≤24, 25-29, 30-34 and 35-44 years. Descriptive summaries are also presented. There were 51,608 nonsyndromic CHD cases in Europe over the 20-year study period. Total prevalence for all CHD combined was increased for younger mothers (≤24 years) and for mothers 35-44 years of age when compared with mothers aged 25-29 years (reference group) (IRR: 1.05, 95% CI: 1.02, 1.07). The total prevalence was increased for severity group I (very severe) only for younger mothers compared to those aged 25-29 years (IRR: 1.14, 95% CI: 1.04, 1.23). We found an increased prevalence of the following CHD subtypes: double outlet right ventricle (IRR:1.33, 95% CI: 1.09, 1.60), hypoplastic left heart syndrome (IRR: 1.18, 95% CI: 1.05, 1.32), hypoplastic right heart syndrome (IRR: 1.41, 95% CI: 1.05, 1.84), atrioventricular septal defect (IRR: 1.15, 95% CI: 1.01, 1.32), coarctation of aorta (IRR: 1.15, 95% CI: 1.03, 1.28) and atrial septal defect (IRR: 1.08, 95% CI: 1.02, 1.13). For older mothers (35-44 years) compared to the reference category, we observed an increased risk in the prevalence for severity group II (IRR: 1.09, 95% CI: 1.03, 1.14), severity group III (IRR: 1.05, 95% CI: 1.01, 1.08) and an increased prevalence of the CHD subtypes: Pulmonary valve stenosis (IRR: 1.22, 95% CI: 1.09, 1.34), ASD (IRR: 1.07, 95% CI: 1.02, 1.13), CoA (IRR: 1.18, 95% CI: 1.06, 1.32) and Tetralogy of Fallot (IRR: 1.14, 95% CI: 1.01, 1.28). Finally, for all age categories compared to the reference category, different associations of ASD and an increased prevalence of CoA was also observed. Based on data for cases of CHD from 24 European population-based registries, evidence of a positive association between maternal age and the total prevalence of CHD for younger (≤24 years old) and older (35-44 years old) mothers was observed. The results suggest that young maternal age (≤24 years old) is a factor associated with severe CHD phenotypes while a positive association between advanced maternal age (35-44 years old) and mild CHD phenotypes was observed.

Incidence of nonsyndromic congenital heart defects in the Republic of Srpska in the period 2015-2016

Background/Aim. Congenital heart defect (CHD) is the most common type of birth defect and one of the leading causes of infant mortality. It can be isolated or occur as a part of multiple different syndromes. The reported worldwide incidence of isolated CHD is between 70 and 120 per 10,000 live births. The aim of the study was to estimate the incidence of nonsyndromic C HD in the Republic of Srpska (RS), Bosnia and Herzegovina and compare it with other countries. Methods. The fetuses, live-born and stillborn infants with CHD during 2015 and 2016 in the RS, were analyzed using data from a cross-sectional study. Results. The total incidence of CHD was 163.95 per 10,000 total births, and the incidence of live-born with CHD was 136.64 per 10,000. The diagnosis was established prenatally in 8.09% of cases. The most common type of anomaly was ventricular septal defect (45.63%), followed by an atrial septal defect (31.40%), patent ductus arteriosus (7.44%), and pulmonary valve stenosis (5.18%). A significant difference in the incidence of CHD between regions and different maternal age groups was found. Conclusion. The incidence of CHD in the RS found in this study is higher than in other studies, with marked heterogeneity between different regions. This study provides baseline data for future monitoring of the risk factor changes and the implementation of primary preventive measures.

Frequency of chromosome 22q11.2 deletion among newborns with non-syndromic congenital heart defects from western Mexico.

Congenital heart defects (CHD) are among the most frequent manifestations of 22q11.2 deletion syndrome. Although we found relatively few studies aimed at specifically detecting 22q11.2 deletion in newborns (NB) with CHD, none of them has been performed in Mexico. We conducted a prospective hospital-based study from January 2017 to March 2021 in the Genetics and Pediatric Cardiology Services of the Hospital Civil de Guadalajara Dr. Juan I. Menchaca (Guadalajara, Mexico). All consecutive NBs identified with any non-syndromic major CHD confirmed by echocardiography were eligible to participate. A total of 98 NBs were included, 51 males and 47 females. Fluorescence in situ hybridization (FISH) analysis was conducted to search for deletion of chromosome 22q11.2 in interphase nuclei of standard lymphocyte cultures. We found eight patients (8.2%) with CHD and the 22q11.2 deletion, all of them with conotruncal defects, particularly of the truncus arteriosus (p = 0.013), tetralogy of Fallot (p = 0.024), and pulmonary atresia with ventricular septal defect (p = 0.031) subtypes. With de exception of one infant with hypocalcemia and another with hypocalcemia and thymic aplasia, the diagnosis of 22q11.2 deletion was not clinically suspected in the other patients. Our results confirm the importance of excluding the presence of the 22q11.2 deletion in every NB with CHDs, particularly of the conotruncal subtype, even in the absence of other manifestations.

Prevalence of congenital heart defects in Europe, 2008-2015: A registry-based study.

The total prevalence of congenital heart defects (CHDs) varies by populations and over time. Studies that examine trends in the prevalence of CHD in different regions may shed light on our understanding of the occurrence of CHD and the impact of different risk factors. To examine trends in total and live birth prevalence of nonsyndromic CHD in Europe between the years 2008 and 2015 and to investigate if the decreasing trend reported by previous studies is continuing. Cases of CHD delivered between January 1, 2008 and December 31, 2015 notified to 25 population-based EUROCAT (European Surveillance of Congenital Anomalies) registries in 14 countries, formed the population-based case-series. Prevalence (total/live) rates and 95% confidence intervals were calculated as the number of cases per 10,000 births (live and stillbirths). Time trends in prevalence of all nonsyndromic CHDs and for three CHD severity groups (very severe, severe, and less severe) were plotted using a Poisson regression multilevel approach. The total prevalence of nonsyndromic CHD was 57.1 per 10,000 births (live births and stillbirths) for the 8-year period and remained stable across the three CHD severity groups while the live birth prevalence was 60.2 per 10,000 births. There was considerable variation in the reported total CHD prevalence and the direction of trends by registry. A decreasing prevalence of CHD was observed for the Norway and England/Wales registries, whereas the CHD prevalence increased for registries in Italy and Croatia. The total prevalence of CHD in Europe between the years 2008 and 2015 remained stable for all CHD and across the three CHD severity groups. The decreasing trend reported by previous studies has not continued. However, we found significant differences in the total and live birth prevalence by registry.

Cell-free DNA in maternal blood and artificial intelligence: accurate prenatal detection of fetal congenital heart defects

DNA cytosine nucleotide methylation (epigenomics and epigenetics) is an important mechanism for controlling gene expression in cardiac development. Combined artificial intelligence and whole-genome epigenomic analysis of circulating cell-free DNA in maternal blood has the potential for the detection of fetal congenital heart defects. This study aimed to use genome-wide DNA cytosine methylation and artificial intelligence analyses of circulating cell-free DNA for the minimally invasive detection of fetal congenital heart defects. In this prospective study, whole-genome cytosine nucleotide methylation analysis was performed on circulating cell-free DNA using the Illumina Infinium MethylationEPIC BeadChip array. Multiple artificial intelligence approaches were evaluated for the detection of congenital hearts. The Ingenuity Pathway Analysis program was used to identify gene pathways that were epigenetically altered and important in congenital heart defect pathogenesis to further elucidate the pathogenesis of isolated congenital heart defects. There were 12 cases of isolated nonsyndromic congenital heart defects and 26 matched controls. A total of 5918 cytosine nucleotides involving 4976 genes had significantly altered methylation, that is, a P value of <.05 along with ≥5% whole-genome cytosine nucleotide methylation difference, in congenital heart defect cases vs controls. Artificial intelligence analysis of the methylation data achieved excellent congenital heart defect predictive accuracy (areas under the receiver operating characteristic curve, ≥0.92). For example, an artificial intelligence model using a combination of 5 whole-genome cytosine nucleotide markers achieved an area under the receiver operating characteristic curve of 0.97 (95% confidence interval, 0.87-1.0) with 98% sensitivity and 94% specificity. We found epigenetic changes in genes and gene pathways involved in the following important cardiac developmental processes: "cardiovascular system development and function," "cardiac hypertrophy," "congenital heart anomaly," and "cardiovascular disease." This lends biologic plausibility to our findings. This study reported the feasibility of minimally invasive detection of fetal congenital heart defect using artificial intelligence and DNA methylation analysis of circulating cell-free DNA for the prediction of fetal congenital heart defect. Furthermore, the findings supported an important role of epigenetic changes in congenital heart defect development.

CNV Analysis Using Multiplex Ligation-Dependent Probe Amplification in Iranian Families with Non-Syndromic Congenital Heart Defects: Early Diagnosis of Non-Syndromic Patients

Background and Aims: Congenital heart defects (CHD) are the most common type of congenital disability. Copy number variations (CNVs) have been found as one of the genetic etiology of non-syndromic CHD, and researchers have detected several pathogenic CNVs in patients with cardiac defects.&#x0D; Materials and Methods: In the present study, 70 patients with familial (20 patients) and sporadic (50 patients) non-syndromic CHD were evaluated to find whether CNVs in the GATA4, NKX2-5, TBX-5, CREL, BMP4 genes, and 22q11.2 region contribute to the pathogenesis of non-syndromic CHD. We have used the Multiplex Ligation-dependent Probe Amplification (MLPA) technique as a molecular method to identify CNVs in predefined loci.&#x0D; Results: Normal MLPA results were demonstrated for GATA4, NKX2-5, TBX-5, CRELD, and BMP4 genes for all sporadic and familial cases. However, we found three patients with imbalances for the 22q11.2 region. One patient with 22q11.2 deletion showed tetralogy of fallot, and the other had ventricular septal defects/ pulmonary atresia/ multiple aortopulmonary collateral arteries. A duplication of the 22q11.2 region was detected in one patient with patent ductus arteriosus.&#x0D; Conclusion: Identifying genomic imbalances in 6% of the non-syndromic sporadic patients indicates that recurrent CNVs could be associated with non-syndromic CHD. It seems that it is the first CNV analysis using MLPA carried out in Iranian patients with cardiac defects. We suggest that 22q11.2 imbalances should be considered in patients with cardiac lesions to provide an accurate diagnosis and appropriate genetic counseling in affected families.

TAB2 variants cause cardiovascular heart disease, connective tissue disorder, and developmental delay.

Congenital heart defects (CHD) are the most commonly occurring birth defect and can occur in isolation or with additional clinical features comprising a genetic syndrome. Autosomal dominant variants in TAB2 are recognized by the American Heart Association as causing nonsyndromic CHD, however, emerging data point to additional, extra-cardiac features associated with TAB2 variants. We identified 15 newly reported individuals with pathogenic TAB2 variants and reviewed an additional 24 subjects with TAB2 variants in the literature. Analysis showed 64% (25/39) of individuals with disease resulting from TAB2 single nucleotide variants (SNV) had syndromic CHD or adult-onset cardiomyopathy with one or more extra-cardiac features. The most commonly co-occurring features with CHD or cardiomyopathy were facial dysmorphism, skeletal and connective tissue defects and most subjects with TAB2 variants present as a connective tissue disorder. Notably, 53% (8/15) of our cohort displayed developmental delay and we suspect this may be a previously unappreciated feature of TAB2 disease. We describe the largest cohort of subjects with TAB2 SNV and show that in addition to heart disease, features across multiple systems are present in most TAB2 cases. In light of our findings, we recommend that TAB2 be included on the list of genes that cause syndromic CHD, adult-onset cardiomyopathy, and connective tissue disorder.

Quality of life of parents with children with congenital abnormalities: a systematic review with meta-analysis of assessment methods and levels of quality of life.

To quantify and understand how to assess the quality of life and health-related QoL of parents with children with congenital abnormalities. We conducted a systematic review with meta-analysis. The search was carried out in 5 bibliographic databases and in ClinicalTrials.gov. No restriction on language or date of publication was applied. This was complemented by references of the studies found and studies of evidence synthesis, manual search of abstracts of relevant congresses/scientific meetings and contact with experts. We included primary studies (observational, quasi-experimental and experimental studies) on parents of children with CA reporting the outcome quality of life (primary outcome) of parents, independently of the intervention/exposure studied. We included 75 studies (35 observational non-comparatives, 31 observational comparatives, 4 quasi-experimental and 5 experimental studies). We identified 27 different QoL instruments. The two most frequently used individual QoL instruments were WHOQOL-Bref and SF-36. Relatively to family QoL tools identified, we emphasized PedsQL FIM, IOFS and FQOL. Non-syndromic congenital heart defects were the CA most frequently studied. Through the analysis of comparative studies, we verified that parental and familial QoL were impaired in this population. This review highlights the relevance of assessing QoL in parents with children with CA and explores the diverse QoL assessment tools described in the literature. Additionally, results indicate a knowledge gap that can help to draw new paths to future research. It is essential to assess QoL as a routine in healthcare providing and to implement strategies that improve it.

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

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

Urine metabolomic biomarkers for prediction of isolated fetal congenital heart defect

Objective To identify maternal second and third trimester urine metabolomic biomarkers for the detection of fetal congenital heart defects (CHDs). Study design This was a prospective study. Metabolomic analysis of randomly collected maternal urine was performed, comparing pregnancies with isolated, non-syndromic CHDs versus unaffected controls. Mass spectrometry (liquid chromatography and direct injection and tandem mass spectrometry, LC–MS–MS) as well as nuclear magnetic resonance spectrometry, 1H NMR, were used to perform the analyses between 14 0/7 and 37 0/7 weeks gestation. A total of 36 CHD cases and 41 controls were compared. Predictive algorithms using urine markers alone or combined with, clinical and ultrasound (US) (four-chamber view) predictors were developed and compared. Results A total of 222 metabolites were identified, of which 16 were overlapping between the two platforms. Twenty-three metabolite concentrations were found in significantly altered in CHD gestations on univariate analysis. The concentration of methionine was most significantly altered. A predictive algorithm combining metabolites (histamine, choline, glucose, formate, methionine, and carnitine) plus US four-chamber view achieved an AUC = 0.894; 95% CI, 0814–0.973 with a sensitivity of 83.8% and specificity of 87.8%. Enrichment pathway analysis identified several lipid related pathways that are dysregulated in CHD, including phospholipid biosynthesis, phosphatidylcholine biosynthesis, phosphatidylethanolamine biosynthesis, and fatty acid metabolism. This could be consistent with the increased risk of CHD in diabetic pregnancies. Conclusions We report a novel, noninvasive approach, based on the analysis of maternal urine for isolated CHD detection. Further, the dysregulation of lipid- and folate metabolism appears to support prior data on the mechanism of CHD.

Systemic Screening for 22q11.2 Copy Number Variations in Hungarian Pediatric and Adult Patients With Congenital Heart Diseases Identified Rare Pathogenic Patterns in the Region.

Congenital heart defects (CHD) are the most common developmental abnormalities, affecting approximately 0.9% of livebirths. Genetic factors, including copy number variations (CNVs), play an important role in their development. The most common CNVs are found on chromosome 22q11.2. The genomic instability of this region, caused by the eight low copy repeats (LCR A-H), may result in several recurrent and/or rare microdeletions and duplications, including the most common, ∼3 Mb large LCR A-D deletion (classical 22q.11.2 deletion syndrome). We aimed to screen 22q11.2 CNVs in a large Hungarian pediatric and adult CHD cohort, regardless of the type of their CHDs. All the enrolled participants were cardiologically diagnosed with non-syndromic CHDs. A combination of multiplex ligation-dependent probe amplification (MLPA), chromosomal microarray analysis and droplet digital PCR methods were used to comprehensively assess the detected 22q11.2 CNVs in 212 CHD-patients. Additionally, capillary sequencing was performed to detect variants in the TBX1 gene, a cardinal gene located in 22q11.2. Pathogenic CNVs were detected in 5.2% (11/212), VUS in 0.9% and benign CNVs in 1.8% of the overall CHD cohort. In patients with tetralogy of Fallot the rate of pathogenic CNVs was 17% (5/30). Fifty-four percent of all CNVs were typical proximal deletions (LCR A-D). However, nested (LCR A-B) and central deletions (LCR C-D), proximal (LCR A-D) and distal duplications (LCR D-E, LCR D-H, LCR E-H, LCR F-H) and rare combinations of deletions and duplications were also identified. Segregation analysis detected familial occurrence in 18% (2/11) of the pathogenic variants. Based on in-depth clinical information, a detailed phenotype–genotype comparison was performed. No pathogenic variant was identified in the TBX1 gene. Our findings confirmed the previously described large phenotypic diversity in the 22q11.2 CNVs. MLPA proved to be a highly efficient genetic screening method for our CHD-cohort. Our results highlight the necessity for large-scale genetic screening of CHD-patients and the importance of early genetic diagnosis in their clinical management.

Common Variation in Cytoskeletal Genes is Associated with Conotruncal Heart Defects.

There is strong evidence for a genetic contribution to non-syndromic congenital heart defects (CHDs). However, exome- and genome-wide studies conducted at the variant and gene-level have identified few genome-wide significant CHD-related genes. Gene-set analyses are a useful complement to such studies and candidate gene-set analyses of rare variants have provided insight into the genetics of CHDs. However, similar analyses have not been conducted using data on common genetic variants. Consequently, we conducted common variant analyses of 15 CHD candidate gene-sets, using data from two common types of CHDs: conotruncal heart defects (1431 cases) and left ventricular outflow tract defects (509 cases). After Bonferroni correction for evaluation of multiple gene-sets, the cytoskeletal gene-set was significantly associated with conotruncal heart defects (βS = 0.09; 95% confidence interval (CI) 0.03–0.15). This association was stronger when analyses were restricted to the sub-set of cytoskeletal genes that have been observed to harbor rare damaging genotypes in at least two CHD cases (βS = 0.32, 95% CI 0.08–0.56). These findings add to the evidence linking cytoskeletal genes to CHDs and suggest that, for cytoskeletal genes, common variation may contribute to the risk of CHDs.

Functional evidence of mTORβ splice variant involvement in the pathogenesis of congenital heart defects.

mTOR dysregulation has been described in pathological conditions, such as cardiovascular and overgrowth disorders. Here we report on the first case of a patient with a complex congenital heart disease and an interstitial duplication in the short arm of chromosome 1, encompassing part of the mTOR gene. Our results suggest that an intragenic mTOR microduplication might play a role in the pathogenesis of non-syndromic congenital heart defects (CHDs) due to an upregulation of mTOR/Rictor and consequently an increased phosphorylation of PI3K/AKT and MEK/ERK signaling pathways in patient-derived amniocytes. This is the first report which shows a causative role of intragenic mTOR microduplication in the etiology of an isolated complex CHD.

Whole-exome sequencing and homozygosity mapping identify variants in NCOR1 and MAP2K3 associated with non-syndromic congenital heart defects

BackgroundHomozygosity mapping is an efficient gene mapping method applicable to recessive disorders. It can detect homozygous segments of identical haplotype structures shared at a higher frequency among ventricular septal defect (VSD) and tetralogy of Fallot (TOF) cases. This study aims to identify the recessive genes involved in congenital heart disease (CHD) cases by homozygosity mapping. A total of 36 CHD cases of Indian origin were recruited based on inclusion and exclusion criteria, disease severity, and hole size. Of these, ten prediagnosed VSD and TOF cases were selected for homozygosity mapping. For in silico validation of variations, overlapping gene variants were analyzed from 26 cases based on pathogenecity and haploinsufficiency scores.ResultsGenome-wide homozygosity mapping identified 34 homozygous regions with a maximum block length of 80 bp marked for the CHD samples under study. A total of 4863 genes were identified in these 34 homozygous regions, which were present across almost all chromosomes except chromosomes 4, 8, 12, and 13. The homozygosity region found in chromosome 17 revealed genes for CHD manifestation. This homozygous region contained VSD- and TOF-related genes—Nuclear Corepressor 1 (NCOR1) and Mitogen-Activated Protein Kinase Kinase 3 (MAP2K3). In silico validation identified damaging variants for NCOR1 and MAP2K3. Three variants, G207C, C241T, and G244A, were found on exon 2 in the transcript NM_001190438 for NCOR1. Three variants were also found for MAP2K3, namely G194T and C199T in exon 5 and C578T in exon 8 in the transcript NM_002756. All these variants were present in the protein kinase domain.ConclusionPresence of homozygous regions identifies recessive genes leading to disease severity. Defects in recessive genes NCOR1 and MAP2K3 are responsible for abnormal myogenesis, resulting in CHD manifestation.

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.