The epidemiology and genetics of congenital heart disease

Understanding the Genetic and Non-Genetic Interconnections in the Aetiology of Syndromic Congenital Heart Disease: An Updated Review: Part 2

PURPOSE OF REVIEW

Approximately 30% of syndromic cases diagnosed with CHD, which lure us to further investigate the molecular and clinical challenges behind syndromic CHD (sCHD). The aetiology of sCHD in a majority of cases remains enigmatic due to involvement of multiple factors, namely genetic, epigenetic and environmental modifiable risk factors for the development of the disease. Here, we aim to update the role of genetic contributors including chromosomal abnormalities, copy number variations (CNVs) and single gene mutations in cardiac specific genes, maternal lifestyle conditions, environmental exposures and epigenetic modifiers in causing CHD in different genetic syndromes.

RECENT FINDINGS

The exact aetiology of sCHD is still unknown. With the advancement of next-generation technologies including WGS, WES, transcriptome, proteome and methylome study, numerous novel genes and pathways have been identified. Moreover, our recent knowledge regarding epigenetic and environmental regulation during cardiogenesis is still evolving and may solve some of the mystery behind complex sCHD. Here, we focus to understand how the complex combination of genetic, environmental and epigenetic factors interact to interfere with developmental pathways, culminating into cardiac and extracardiac defects in sCHD.

Association of maternal and paternal risk factors with risk of congenital heart disease in infants: a case-control study

OBJECTIVE

We aimed to explore maternal and paternal risk factors with risk of congenital heart disease in infants.

METHODS

A total of 125 congenital heart disease (CHD) infants and 125 controls were included in Heping Hospital Affiliated to Changzhi Medical College, Shanxi, China. Subjects were diagnosed between Jan 1, 2016 and Dec 31, 2021 in the present study. All the characteristics were collected with questionnaire by face-to-face interview, including maternal and paternal risk factors. Conditional logistic regression was conducted to explore the risk factors with risk of congenital heart disease in infants.

RESULTS

For maternal risk factors, we found that age, number of pregnancies, systolic blood pressure (SBP), diastolic blood pressure (DBP), and body mass index (BMI) were risk factors for CHD infants, and the ORs (95%CIs) were 1.15 (1.06-1.23) for age, 1.13 (1.02-1.29) for SBP, 1.06 (1.02-1.18) for DBP, 1.22 (1.16-1.31) for BMI. Compared with one pregnancy, the ORs (95%CIs) were 1.17 (1.05-1.29) for two pregnancies and 1.25 (1.16-1.47) for more pregnancies. For paternal risk factors, we found that age (OR = 1.07, 95%CI = 1.01-1.19), smoking (OR = 1.11, 95%CI = 1.03-1.27), drinking (OR = 1.04, 95%CI = 1.02-1.19), and BMI (OR = 1.15, 95%CI = 1.03-1.28) were risk factors for CHD infants.

CONCLUSION

We found that age, number of pregnancies, SBP, DBP, and BMI are maternal risk factors for CHD infants. And age, smoking, drinking, and BMI are paternal risk factors for CHD infants.

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

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

Complete Isolation of Left Innominate Artery in a Patient With CHARGE Syndrome: Case Presentation and Review of Reported Cases

We report a rare case of complete isolation of the left innominate artery in a child with CHARGE (coloboma, heart defects, atresia choanae, growth retardation, genital abnormalities, and ear abnormalities) syndrome. This anatomical cluster had been undetected for a relatively large period of time and the patient was referred to us with an incomplete diagnosis even after multiple medical evaluations and a thoracic surgery during the neonatal period. In conclusion, to the best of our knowledge, this is the first case of a complete isolation of left innominate artery treated with a transcatheter approach.

Neuroimaging and Cerebrovascular Changes in Fetuses with Complex Congenital Heart Disease

Background: Congenital heart diseases (CHDs) are often associated with significant neurocognitive impairment and neurological delay. This study aims to elucidate the correlation between type of CHD and Doppler velocimetry and to investigate the possible presence of fetal brain abnormalities identified by magnetic resonance imaging (MRI). Methods: From July 2010 to July 2020, we carried out a cross-sectional study of 63 singleton pregnancies with a diagnosis of different types of complex CHD: LSOL (left-sided obstructive lesions; RSOL (right-sided obstructive lesions) and MTC (mixed type of CHD). All patients underwent fetal echocardiography, ultrasound evaluation, a magnetic resonance of the fetal brain, and genetic counseling. Results: The analysis of 63 fetuses shows statistically significant results in Doppler velocimetry among the different CHD groups. The RSOL group leads to higher umbilical artery (UA-PI) pressure indexes values, whereas the LSOL group correlates with significantly lower values of the middle cerebral artery (MCA-PI) compared to the other subgroups (p = 0.036), whereas the RSOL group shows a tendency to higher pulsatility indexes in the umbilical artery (UA-PI). A significant correlation has been found between a reduced head circumference (HC) and the presence of brain injury at MRI (p = 0.003). Conclusions: Congenital left- and right-sided cardiac obstructive lesions are responsible for fetal hemodynamic changes and brain growth impairment. The correct evaluation of the central nervous system (CNS) in fetuses affected by CHD could be essential as prenatal screening and the prediction of postnatal abnormalities.

Genetic insights into non-syndromic Tetralogy of Fallot

Congenital heart defects (CHD) include structural abnormalities of the heart or/and great vessels that are present at birth. CHD affects around 1% of all newborns worldwide. Tetralogy of Fallot (TOF) is the most prevalent cyanotic congenital cardiac abnormality, affecting three out of every 10,000 live infants with a prevalence rate of 5-10% of all congenital cardiac defects. The four hallmark characteristics of TOF are: right ventricular hypertrophy, pulmonary stenosis, ventricular septal defect, and overriding aorta. Approximately 20% of cases of TOF are associated with a known disease or chromosomal abnormality, with the remaining 80% of TOF cases being non-syndromic, with no known aetiology. Relatively few TOF patients have been studied, and little is known about critical causative genes for non-syndromic TOF. However, rare genetic variants have been identified as significant risk factors for CHD, and are likely to cause some cases of TOF. Therefore, this review aims to provide an update on well-characterized genes and the most recent variants identified for non-syndromic TOF.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Neurodevelopmental Outcomes in Tetralogy of Fallot: A Systematic Review

BACKGROUND

Tetralogy of Fallot (TOF) represents between 7 and 10% of the total cases of congenital heart defects (CHD) and is estimated to be the most common cyanotic CHD, requiring medical or surgical intervention within the first year of life. Current advances in prenatal screening and fetal echocardiography led to increased rates of prenatal diagnosis of TOF. Furthermore, improvements in initial medical care, surgical repair, and long-term care are associated with excellent long-term survival until adulthood. Consequently, issues of morbidity have come under the spotlight, specifically neurodevelopmental and psychiatric adverse outcomes, which affect the quality of life of TOF survivors.

METHOD

This study is a systematic review of English articles, using PUBMED and applying the following search terms, Tetralogy of Fallot, neurodevelopment, autism, cerebral palsy, attention-deficit hyperactivity disorder. Data were extracted by two authors.

RESULTS

Most researchers suggest that TOF survivors score lower in neurodevelopmental tests than healthy populations of the same age and are in danger of neurodevelopmental impairments. Furthermore, it is suggested that TOF adolescents show higher rates of psychiatric disorders.

CONCLUSIONS

The neurodevelopment of TOF survivors is not intensively studied. Existing studies in TOF survivors focus on different developmental aspects, using different evaluation methods and thus making conclusions for either one of the four aspects of neurodevelopment (executive function, cognition, and adaptive function, speech-language and motor function, or neuropsychiatric domain). The poor outcomes of these isolated studies indicate the need for future research as well as for continuous neuropsychological assessment and close monitoring of children and adolescents with TOF.

Aortic Arch Variants and Anomalies: Embryology, Imaging Findings, and Clinical Considerations

There is a wide spectrum of congenital anomalies or variations of the aortic arch, ranging from non-symptomatic variations that are mostly detected incidentally to clinically symptomatic variations that cause severe respiratory distress or esophageal compression. Some of these may be accompanied by other congenital heart diseases or chromosomal anomalies. The widespread use of multidetector computed tomography (CT) in clinical practice has resulted in incidental detection of several variations of the aortic arch in adults. Thus, radiologists and clinicians should be aware of the classification of aortic arch anomalies and carefully look for imaging features associated with a high risk of clinical symptoms. Understanding the embryological development of the aortic arch aids in the classification of various subtypes of aortic arch anomalies and variants. For accurate diagnosis and precise evaluation of aortic arch anomalies, cross-sectional imaging modalities, such as multidetector CT or magnetic resonance imaging, play an important role by providing three-dimensional reconstructed images. In this review, we describe the embryological development of the thoracic aorta and discuss variations and anomalies of the aortic arch along with their clinical implications.

MicroRNA-375 overexpression disrupts cardiac development of Zebrafish (Danio rerio) by targeting notch2

MicroRNAs are small noncoding RNAs that are important for proper cardiac development. In our previous study of fetuses with ventricular septal defects, we discovered that microRNA-375 (miR-375) is obviously upregulated compared with that in healthy controls. Our study also confirmed that miR-375 is crucial for cardiomyocyte differentiation. This research mainly focused on the biological significance and mechanism of miR-375 using a zebrafish model. We injected zebrafish embryos with 1-2 nl of a miR-375 mimic at various concentrations (0/2/4/8 μM) or with negative control. The deformation and mortality rates were separately assessed. The different expression levels of miR-375 and related genes were examined by qRT-PCR, and luciferase assays and in situ hybridization were used to clarify the mechanism of miR-375 during embryonic development. Overexpression of miR-375 disrupted the cardiac development of zebrafish embryos. Disruption of miR-375 led to a decreased heart rate, pericardial edema, and abnormal cardiac looping. Various genes involved in cardiac development were downregulated due to the overexpression of miR-375. Moreover, the NOTCH signaling pathway was affected, and the luciferase reporter gene assays confirmed notch2, which was predicted by bioinformatics analysis, as the target gene of miR-375. Our findings demonstrated that the overexpression of miR-375 is detrimental to embryonic development, including cardiac development, and can partially simulate a multisystemic disorder. MiR-375 has an important role during cardiac morphogenesis of zebrafish embryos by targeting notch2, indicating its potential as a diagnostic marker.

The correlation of TGFβ1 gene polymorphisms with congenital heart disease susceptibility

OBJECTIVE

The aim of this study was to investigate the relationship between single nucleotide polymorphisms (SNPs) in transforming growth factor beta 1 (TGFβ1) gene (rs1982073 and rs1800471) and congenital heart disease (CHD) susceptibility.

METHODS

Totally, 145 CHD patients and 140 healthy controls were enrolled in this case-control study. The case and control groups were matched in age and gender. Genotyping for TGFβ1 gene SNPs rs1982073 and rs1800471 was conducted via polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) approach. Chi-square test was used to analyze the association of TGFβ1 polymorphisms with CHD risk. The results were presented as odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

The frequencies of the CT genotype and T allele of TGFβ1 gene SNP rs1982073 were significantly different between cases and controls (P < 0.05), revealing their associations with reduced susceptibility to CHD (OR = 0.521, 95%CI = 0.302-0.897; OR = 0.706, 95%CI = 0.507-0.983). Nevertheless, TGFβ1 gene SNP rs1800471 had no significant association with CHD susceptibility (P > 0.05).

CONCLUSION

TGFβ1 gene SNP rs1982073 might be correlated with CHD susceptibility, and the T allele might decrease the disease risk. However, TGFβ1 gene polymorphism rs1800471 was not related to CHD risk.

sox9b is required in cardiomyocytes for cardiac morphogenesis and function

The high mobility group transcription factor SOX9 is expressed in stem cells, progenitor cells, and differentiated cell-types in developing and mature organs. Exposure to a variety of toxicants including dioxin, di(2-ethylhexyl) phthalate, 6:2 chlorinated polyfluorinated ether sulfonate, and chlorpyrifos results in the downregulation of tetrapod Sox9 and/or zebrafish sox9b. Disruption of Sox9/sox9b function through environmental exposures or genetic mutations produce a wide range of phenotypes and adversely affect organ development and health. We generated a dominant-negative sox9b (dnsox9b) to inhibit sox9b target gene expression and used the Gal4/UAS system to drive dnsox9b specifically in cardiomyocytes. Cardiomyocyte-specific inhibition of sox9b function resulted in a decrease in ventricular cardiomyocytes, an increase in atrial cardiomyocytes, hypoplastic endothelial cushions, and impaired epicardial development, ultimately culminating in heart failure. Cardiomyocyte-specific dnsox9b expression significantly reduced end diastolic volume, which corresponded with a decrease in stroke volume, ejection fraction, and cardiac output. Further analysis of isolated cardiac tissue by RT-qPCR revealed cardiomyocyte-specific inhibition of sox9b function significantly decreased the expression of the critical cardiac development genes nkx2.5, nkx2.7, and myl7, as well as c-fos, an immediate early gene necessary for cardiomyocyte progenitor differentiation. Together our studies indicate sox9b transcriptional regulation is necessary for cardiomyocyte development and function.

Isolated left brachiocephalic artery with the right aortic arch: A rare differential of large patent ductus arteriosus

We report a case of isolation of the left brachiocephalic artery with the right aortic arch in a 9-year-old male child masquerading as large patent ductus arteriosus with left-to-right shunt. We have emphasized the subtle clinical findings which served as clues to the diagnosis.

Maternal hyperhomocysteinemia and congenital heart defects: A prospective case control study in Indian population

Objective

Very few studies have been conducted in this part of world to identify relation between maternal serum homocysteine levels and congenital heart disease in their offsprings. With this perspective in mind, this study was carried out.

Methods

Fifty women were enrolled in this study. Thirty of these had delivered neonates who were diagnosed to have congenital heart diseases. These were treated as cases. Twenty of these women had delivered neonates who did not have any congenital heart diseases and were treated as controls. For estimating the levels of plasma homocysteine, fasting blood samples were taken from the women in both groups.

Results

Out of 30 cases, 14 (46.6%) had a tHcy level more than 15 μmol/l and all these women had delivered babies who were found to have congenital heart diseases. Out of controls, only 3 (15%) had a tHcy level more than 15 μmol/l. In babies with ventricular septal defects, the mean maternal plasma tHcy level was 13.30 μmol/l. In babies with Tetralogy of Fallot, the mean maternal plasma tHcy level was 40.07 μmol/l. In babies with Transposition of Great Vessels, the mean maternal plasma tHcy level was 40.93 μmol/l. In babies with Tricuspid atresia, the mean maternal plasma tHcy level was 24.89 μmol/l.

Conclusions

Increased levels of maternal serum homocysteine are associated with increased risk of occurrence of congenital heart defects in their offsprings, suggesting that maternal hyperhomocysteinemia is an independent risk factor for congenital heart defects.

Detection of chromosomal abnormalities and the 22q11 microdeletion in fetuses with congenital heart defects

Chromosomal abnormalities and the 22q11 microdeletion are implicated in congenital heart defects (CHDs). This study was designed to detect these abnormalities in fetuses and determine the effect of genetic factors on CHD etiology. Between January 2010 and December 2011, 113 fetuses with CHD treated at the Beijing Obstetrics and Gynecology Hospital were investigated, using chromosome karyotyping of either amniotic fluid cell or umbilical cord blood cell samples. Fetuses with a normal result were then investigated for the 22q11 microdeletion by fluorescence in situ hybridization. Of the 113 patients, 12 (10.6%) exhibited chromosomal abnormalities, while 6 (5.3%) of the remaining 101 cases presented with a 22q11 microdeletion. The incidence of chromosomal abnormalities was significantly higher in the group of fetuses presenting with extracardiac malformations in addition to CHD (P<0.001), although the detection of the 22q11 microdeletion was not significantly different between the two groups (P=0.583). In addition, all fetuses with the 22q11 microdeletion occurred de novo. In conclusion, genetic factors are important in the etiology of CHD. Where fetuses present with cardiac defects, additional chromosomal analysis is required to detect extracardiac abnormalities. Fetuses with heart defects should also be considered for 22q11 microdeletion detection to evaluate fetal prognosis, particularly prior to surgery.

Clinical examination and pulse oximetry as screening for congenital heart disease in low-risk newborn

OBJECTIVE

To assess sensitivity, specificity, positive predictive value and negative predictive value of the cardiovascular physical examination (CPE) and of pulse oximetry in screening for congenital heart diseases (CHD) in asymptomatic newborn when prenatal ultrasound evaluation is negative for structural cardiac abnormalities.

METHODS

In this observational cohort study, 5750 asymptomatic newborns, admitted to nursery in a period of 2 years, underwent to CPE and determination of arterial oxygen saturation by pulse oxymetry between 48th and 72nd h of life.

RESULTS

Two hundred and ninty-eight newborns presented a suspected CPE; in 70% of cases, we found a transitional alteration and in only 17% of cases, the echocardiography examination performed for suspected CPE were completely negative. Three newborns were positive to pulse oximetry screening test but negative at CPE. After discharge, one case of critical CHD was diagnosed.

CONCLUSIONS

An accurate CPE performed by trained and experienced pediatricians is indicative of important cardiac structural alteration in more than 25%. The association of CPE and pulse oximetry allows to further improve the diagnostic accuracy.

Identification of novel significant variants of ZFPM2/FOG2 in non-syndromic Tetralogy of Fallot and double outlet right ventricle in a Chinese Han population

Tetralogy of Fallot (TOF) and double outlet right ventricle (DORV) are two common subtypes of conotruncal defects. Recent reports have implicated mutations in the zinc finger protein, FOG family member 2 (ZFPM2/FOG2) as a cause of TOF/DORV, but no current literature focuses on the relationship between ZFPM2/FOG2 gene and non-syndromic TOF and DORV in Chinese Han population. The purpose of this study was to estimate the occurrence and the prevalence of ZFPM2/FOG2 genetic variants in Chinese Han population with non-syndromic TOF and DORV and to investigate genotype-phenotype correlations in individuals with ZFPM2/FOG2 mutations. The whole exons of ZFPM2/FOG2 were sequenced in 98 non-syndromic TOF/DORV patients and 200 control subjects. All the six variants (G2482A, G1552A, A2107C, C452T, C3239T, C1208G) changed the amino acid (p.Val828Met, p.Ala518Thr, p.Met703Leu, p.Thr151Ile, p.Ser1080Phe, p.Ala403Gly), in which four variants (G2482A, C452T, G1552A, C3239T) were not reported before and absent in control subjects. Further analysis revealed that only occurrences of variants G2482A and A2107C had statistical significance compared to the control group (P < 0.05). In conclusion, our results provide strong evidence regarding the susceptibility of the ZFPM2 gene to the development of non-syndromic TOF/DORV. It suggests that ZFPM2/FOG2 genetic variants may be a novel potential bio-markers and treatment targets for the non-syndromic TOF and DORV.

The role of pygopus in the differentiation of intracardiac valves in Drosophila

Cardiac valves serve an important function; they support unidirectional blood flow and prevent blood regurgitation. Wnt signaling plays an important role in the formation of mouse cardiac valves and cardiac valve proliferation in Zebrafish, but identification of the specific signaling components involved has not been addressed systematically. Of the components involved in Wnt signal transduction, pygopus (pygo), first identified as a core component of Wnt signaling in Drosophila, has not yet to be investigated with respect to valve development and differentiation. Here, we take advantage of the Drosophila heart model to study the role of pygo in formation of valves between the cardiac chambers. We found that cardiac-specific pygo knockdown in the Drosophila heart causes dilation in the region of these cardiac valves, and their characteristic dense mesh of myofibrils does not form and resembles that of neighboring cardiomyocytes. In contrast, heart-specific knockdown of the transcription factors, arm/β-Cat, lgs/BCL9, or pan/TCF, which mediates canonical Wnt signal transduction, shows a much weaker valve differentiation defect. Double-heterozygous combinations of mutants for pygo and the Wnt-signaling components have no additional effect on heart function compared with pygo heterozygotes alone. These results are consistent with the idea that pygo functions independently of canonical Wnt signaling in the differentiation of the adult interchamber cardiac valves.

Environmental origins of congenital heart disease: the heart-placenta connection

Although the mammalian embryo is well protected in the uterus, environmental chemicals, drugs, and maternal nutritional imbalances can interfere with regulatory pathways directing placental and embryonic development early in gestation. Embryonic cells are most susceptible to environmental influences during cellular specification and differentiation stages. Because biochemical differentiation precedes morphological outcome often by days, the period of susceptibility to environmental chemicals expectedly precedes visible morphogenic effects. The cellular mechanisms by which drugs and other environmental factors disrupt embryonic development and induce cardiac abnormalities have remained undefined.

The heart-placenta axis in the first month of pregnancy: induction and prevention of cardiovascular birth defects

Extrapolating from animal studies to human pregnancy, our studies showed that folate (FA) deficiency as well as one-time exposure to environmental factors in the first two to three weeks of human gestation can result in severe congenital heart defects (CHDs). Considering that approximately 49% of pregnancies are unplanned, this period of pregnancy can be considered high-risk for cardiac, as well as for neural, birth defects, as the woman usually is not aware of her pregnancy and may not yet be taking precautionary actions to protect the developing embryo. Using avian and mouse vertebrate models, we demonstrated that FA supplementation prevents CHD induced by alcohol, lithium, or elevation of the metabolite homocysteine, a marker for FA deficiency. All three factors affected the important Wnt signaling pathway by suppressing Wnt-mediated gene expression in the heart fields, resulting in a delay of cardiomyocyte migration, cardiomyogenesis, and CHD. Optimal protection of cardiogenesis was observed to occur with FA supplementation provided upon morning after conception and at higher doses than the presently available in prenatal vitamin supplementation. Our studies demonstrate pathways and cell processes that are involved with protection of one-carbon metabolism during heart development.

Malformações do sistema nervoso central e malformações associadas diagnosticadas pela ultrassonografia obstétrica

OBJETIVO: Identificar a prevalência de malformações congênitas do sistema nervoso central (SNC) e malformações associadas diagnosticadas pela ultrassonografia obstétrica. MATERIAIS E MÉTODOS: Estudo observacional, transversal, descritivo, em instituição de referência para gestações de alto risco. RESULTADOS: Malformações congênitas do SNC estiveram presentes sem outras malformações associadas em 65,78%, com a distribuição: hidrocefalia (37,5%), mielomeningocele (15%), encefalocele (12,5%), agenesia de corpo caloso (12,5%), anencefalia (12,5%), holoprosencefalia (7,5%), Dandy-Walker (7,5%), Arnold-Chiari (5,0%), hidranencefalia (5,0%), meningocele (5,0%), cisto aracnoideo (2,5%). Malformações congênitas de outros sistemas estiveram associadas às do SNC: craniofacial (73,9%), ortopédica (65,2%), cardiovascular (34,8%), geniturinária (30,4%), gastrintestinal (30,4%), respiratória (8,7%), sindrômica (8,7), oftalmológica (4,3%). A sensibilidade ultrassonográfica no estudo de malformações fetais do SNC foi 79,4%. A taxa de falso-negativos foi 20,5%. Dentre as limitações quantificáveis destaca-se o oligodrâmnio, presente em 25% dos falso-negativos. CONCLUSÃO: A ultrassonografia obstétrica possui boa sensibilidade no rastreio de malformações fetais do SNC, em especial com o aperfeiçoamento constante e domínio na utilização de métodos especializados, como o Doppler e a ultrassonografia volumétrica (3D/4D), contribuindo para firmar-se como modalidade de escolha nesta rotina. Complementar ao método, a ressonância magnética pode vir a fornecer subsídios para uma ainda melhor assistência perinatal.

Gestational and family risk factors for carriers of congenital heart defects in southern Brazil

BACKGROUND

Congenital heart disease (CHD) is a serious threat to public health. Despite this, its etiology is poorly understood and few cardiac teratogens have been defined. The aim of the present study was to identify gestational and family risk factors for CHD in a sample of patients from a pediatric hospital in southern Brazil.

METHODS

A prospective and consecutive sample from subjects with or without CHD, hospitalized at a pediatric intensive care unit, was enrolled. All patients with CHD underwent a GTG-banding karyotype. Chromosomal abnormalities were observed in 47 subjects (15.8%), and these were excluded from the study. The final sample consisted of 250 CHD subjects and 303 controls.

RESULTS

After statistical analysis, using logistic regression, the variables age, rural location, gestational loss, use of anti-hypertensive medication, antibiotics and alcohol in the first trimester of pregnancy were all independently associated with CHD. These results were similar to those of some studies and different from others. It should be noted, however, that, for several variables, the data in the literature as well as the present study were insufficient to determine risk.

CONCLUSIONS

Some differences found may be explained by genetic factors and sociocultural diversity. In contrast, because CHD consists of a heterogeneous group of lesions, the etiology may vary. The standardization of research data and classification of methods for future studies are essential.

Síndrome de deleção 22q11.2 e cardiopatias congênitas

OBJETIVO: Revisar as características clínicas, etiológicas e diagnósticas da síndrome de deleção 22q11 e sua associação com as cardiopatias congênitas. FONTES DOS DADOS: Foram pesquisados artigos científicos presentes nos portais Medline, Lilacs e SciELO, utilizando-se descritores específicos como "22q11", "DiGeorge syndrome", "velocardiofacial syndrome", "congenital heart defects" e "cardio-vascular malformations". O período adotado para a revisão foi de 1980 a 2009. SÍNTESE DOS DADOS: As malformações cardíacas são os defeitos congênitos observados mais frequentemente ao nascimento e representam um problema importante de Saúde Pública. Dentre suas principais causas conhecidas destaca-se a síndrome de deleção 22q11, também chamada de síndrome de DiGeorge, síndrome velocardiofacial e CATCH22. Trata-se de uma doença autossômica domi-nante caracterizada por um fenótipo altamente variável, o que dificulta em muito seu reconhecimento clínico. Além disso, a maior parte dos pacientes apresenta uma microdeleção identificada principalmente por técnicas de citogenética molecular, como a hibridização in situ fluorescente, pouco disponíveis em nosso meio. De forma similar a outras síndromes, a síndrome de deleção 22q11 associa-se a certos defeitos cardíacos específicos, no caso os do tipo conotruncal. Apesar disso, não há ainda na literatura um consenso sobre quais os pacientes com car-diopatia congênita que deveriam ser investigados para a síndrome de deleção 22q11. CONCLUSÕES: Cardiologistas e cirurgiões cardíacos, espe-cialmente pediátricos, devem estar cientes das peculiaridades e dos cuidados dispensados à síndrome de deleção 22q11. Os indivíduos com a síndrome apresentam comumente alterações envolvendo vários sistemas, o que pode levar a dificuldades e a complicações durante seu manejo clínico e cirúrgico.

Systematic survey of variants in TBX1 in non-syndromic tetralogy of Fallot identifies a novel 57 base pair deletion that reduces transcriptional activity but finds no evidence for association with common variants

Background

Tetralogy of Fallot (TOF) is common in individuals with hemizygous deletions of chromosome 22q11.2 that remove the cardiac transcription factor TBX1.

Objective

To assess the contribution of common and rare TBX1 genetic variants to TOF.

Design

Rare TBX1 variants were sought by resequencing coding exons and splice-site boundaries. Common TBX1 variants were investigated by genotyping 20 haplotype-tagging SNPs capturing all the common variations present at the locus. Association analysis was performed using the program UNPHASED.

Patients

TBX1 exons were sequenced in 93 patients with non-syndromic TOF. Single nucleotide polymorphism analysis was performed in 356 patients with TOF, their parents and healthy controls.

Results

Three novel variants not present in 1000 chromosomes from healthy ethnically matched controls were identified. One of these variants, an in-frame 57 base-pair deletion in the third exon which removed 19 evolutionarily conserved residues, decreased transcriptional activity by 40% in a dual luciferase assay (p=0.008). Protein expression studies demonstrated that this mutation affected TBX1 protein stability. After correction for multiple comparisons, no significant associations between common genetic variants and TOF susceptibility were found.

Conclusion

This study demonstrates that rare TBX1 variants with functional consequences are present in a small proportion of non-syndromic TOF.

Differential duplication of an intronic region in the NFATC1 gene in patients with congenital heart disease

Most forms of congenital heart disease (CHD) result from aberrations in cardiac morphogenesis including errors in septation, valve formation, and proper patterning of the great vessels. Transcription factors are key proteins that dictate mRNA synthesis rate and subsequent protein production in most eukaryotes. NFATC1 belongs to the Rel family of transcription factors. In mice, it is expressed in the embryonic heart and is restricted to the endocardium where it plays a major role in valve formation. To establish a role for NFATC1 in CHD, we started screening for mutations in the exons encoding the DNA-binding domain of NFATC1 in patients enrolled in our study on CHD in Lebanon. DNA was extracted from patients with pulmonary stenosis (PS), tricuspid atresia (TA) and ventricular septal defect (VSD). PCR amplification and DNA sequencing were done on the patients and their parents and (or) siblings. PCR amplification of the exon 7 region showed that 2 bands are obtained in 57% of patients with CHD (32/56) and in 45% of their healthy parents and (or) siblings. Sequencing of the 2 bands revealed that both are amplicons of the exon 7 region, and that the additional band harbors an additional 44 nucleotides segment in the intronic region. The homozygous form of this allele was only present in patients with VSD (2/21). A screen of a pool of 81 healthy, unrelated individuals showed no presence for the homozygous form of this allele, suggesting that NFATC1 is a potential VSD-susceptibility gene.

Homocysteine Concentrations and Molecular Analysis in Patients with Congenital Heart Defects

BACKGROUND

Congenital heart defects are the result of incomplete heart development and, like many diseases, have been associated with high homocysteine concentration.

METHODS

We evaluated homocysteine, folic acid and vitamin B(12) concentrations, and the mutations 677C>T and 1298A>C in MTHFR, 844ins68 in CBS and 2756A>G in MTR genes in 58 patients with congenital heart defects, 38 control subjects, and mothers of 49 patients and 26 controls.

RESULTS

Control and patients presented normal range concentrations for homocysteine (7.66 +/- 3.16 microM and 6.95 +/- 3.12 microM, respectively), folic acid (8.31 +/- 3.00 ng/mL and 11.84 +/- 10.74 ng/mL) and vitamin B(12,) (613.56 +/- 307.57 pg/mL and 623.37 +/- 303.12 pg/mL), which did not differ among groups. For the mothers studied, homocysteine and vitamin B(12) concentrations also did not differ between groups. However, folic acid concentrations of mothers showed significant difference, the highest values being in the group of patients. No difference was found in allele frequencies among all groups studied.

CONCLUSIONS

In the studied groups, high homocysteine seems not to be correlated with congenital heart defects, as well as folic acid and vitamin B(12). The mutations studied, in isolation, were not related to congenital heart defects, but high concentration of maternal homocysteine is associated with the presence of three or four mutated alleles.

Apoptosis in the developing mouse heart

Apoptosis occurs at high frequency in the myocardium of the developing avian cardiac outflow tract (OFT). Up- or down-regulating apoptosis results in defects resembling human conotruncal heart anomalies. This finding suggested that regulated levels of apoptosis are critical for normal morphogenesis of the four-chambered heart. Recent evidence supports an important role for hypoxia of the OFT myocardium in regulating cell death and vasculogenesis. The purpose of this study was to determine whether apoptosis in the outflow tract myocardium occurs in the mouse heart during developmental stages comparable to the avian heart and to determine whether differential hypoxia is also present at this site in the murine heart. Apoptosis was detected using a fluorescent vital dye, Lysotracker Red (LTR), in the OFT myocardium of the mouse starting at embryonic day (E) 12.5, peaking at E13.5-14.5, and declining thereafter to low or background levels by E18.5. In addition, high levels of apoptosis were detected in other cardiac regions, including the apices of the ventricles and along the interventricular sulcus. Apoptosis in the myocardium was detected by double-labeling with LTR and cardiomyocyte markers. Terminal deoxynucleotidyl transferase-mediated deoxyuridinetriphosphate nick end-labeling (TUNEL) and immunostaining for cleaved Caspase-3 were used to confirm the LTR results. At the peak of OFT apoptosis in the mouse, the OFT myocardium was relatively hypoxic, as indicated by specific and intense EF5 staining and HIF1alpha nuclear localization, and was surrounded by the developing vasculature as in the chicken embryo. These findings suggest that cardiomyocyte apoptosis is an evolutionarily conserved mechanism for normal morphogenesis of the outflow tract myocardium in avian and mammalian species.

Impacto das malformações congênitas na mortalidade perinatal e neonatal em uma maternidade-escola do Recife

OBJETIVOS: determinar a incidência de malformações congênitas em recém-nascidos assistidos em uma maternidade-escola de Recife e avaliar o impacto destas malformações na mortalidade perinatal e neonatal. MÉTODOS: realizou-se um estudo longitudinal durante os meses de setembro de 2004 a maio de 2005, analisando-se todos os partos assistidos no Instituto Materno Infantil Prof. Fernando Figueira, IMIP. Determinou-se a freqüência e o tipo de malformações congênitas e foram calculados os coeficientes de mortalidade fetal, mortalidade perinatal, mortalidade neonatal precoce e tardia. RESULTADOS: a freqüência de malformações foi de 2,8% (em 4043 nascimentos). O percentual de malformações entre os nativivos foi de 2,7%, e entre os natimortos foi de 6,7%. Dentre as malformações, as mais freqüentes foram as do sistema nervoso central (principalmente hidrocefalia e meningomielocele), as do sistema osteomuscular e as cardiopatias. Não houve associação entre malformações e sexo, porém a freqüência de prematuridade e baixo peso foi maior entre os casos de malformações. Constatou-se, entre os malformados, mortalidade neonatal precoce de 32,7% e tardia de 10,6%. Os casos de malformações representaram 6,7% dos natimortos, 24,2% das mortes neonatais precoces e 25,8% do total de mortes neonatais. CONCLUSÕES: a freqüência de malformações correspondeu a 2,8% dos nascimentos. As malformações representaram a segunda causa mais freqüente de mortes neonatais, depois da prematuridade.

Trends in fetal echocardiography and implications for clinical practice: 1985 to 2003

OBJECTIVE

The purpose of this study was to determine whether patterns of referral for fetal echocardiography (FE) and the subsequent yield for structural congenital heart disease (CHD) have changed between 1985 and 2003.

METHODS

All FE performed between 1985 and 2003 at Yale-New Haven Hospital was reviewed. The primary indication for study and the presence of structural CHD were recorded, and data were analyzed for trends. Linear regression with Pearson coefficient calculation and Mantel-Haenszel chi(2) analysis were performed (P < .05 significant).

RESULTS

Between 1985 and 2003, 10,806 patients had FE at Yale-New Haven Hospital, and 774 cases of structural CHD were detected. The annual number of studies and rate of detected structural CHD remained constant through the study period. There was a significant increase in the proportion of studies for diabetes, maternal structural CHD, suspicious 4-chamber heart, and family history of cardiac disease. There was a significant decrease in the proportion of studies for a previous child with structural CHD, cardiac teratogen exposure, other fetal anomalies, aneuploidy, fetal arrhythmia, and nonimmune hydrops. The percentage of structural CHD detected by indication remained constant through the study period. Subgroup analysis of diabetes revealed an increase in class B diabetes, while classes C and D remained stable.

CONCLUSIONS

This is one of the largest series of FE and suggests that the pattern of indications has changed since 1985. Specifically, referral for diabetes (mostly class B) has increased without a change in yield of structural CHD by indication for sonography. The changing referral patterns reflect a change in obstetric demographics and has implications for obstetric care.

Outcome of pregnancy in patients after repair of aortic coarctation

AIMS

Nowadays, most women born with aortic coarctation reach childbearing age. However, data on outcome of pregnancy in women after repair of aortic coarctation are scarce. The aim of this study was to report on maternal and neonatal outcome of pregnancy in women after aortic coarctation repair.

METHODS AND RESULTS

The CONCOR national registry on congenital heart disease in The Netherlands was reviewed for women of childbearing age (> or =18 years old) with a history of aortic coarctation repair. Medical history and maternal, obstetrical, and neonatal outcome were determined. Fifty-four of the 100 women included had a history of pregnancy. The 54 women had 126 pregnancies resulting in 98 successful pregnancies, 22 miscarriages, and six abortions. The success rate was estimated as 0.778 (SE 0.002) including abortions and 0.817 (SE 0.002) excluding abortions. There were 85 vaginal deliveries, seven vaginal deliveries with epidural analgesia, and six caesarean sections. There were two neonatal deaths. A total of 26 pregnancies were complicated by a hypertensive disorder of pregnancy. There were 21 pregnancies in 14 women complicated by hypertension and five pregnancies in four women complicated by pre-eclampsia. The hypertension- and pre-eclampsia-probabilities were estimated as 0.183 (SE 0.285) and 0.061 (SE 0.211), respectively. During pregnancy, five patients had an increase > or =15 mmHg across the site of repair at echocardiography, but only one patient required reintervention for recoarctation after delivery. Four of the 98 children (4%) had a congenital heart defect.

CONCLUSION

Pregnancy is well tolerated in women after repair of aortic coarctation. However, an excess of miscarriages and hypertensive disorders of pregnancy were found.

CONCOR, an initiative towards a national registry and DNA-bank of patients with congenital heart disease in the Netherlands: Rationale, design, and first results

INTRODUCTION

Survival of patients with congenital heart disease has dramatically improved after surgical repair became available 40 years ago. Instead of a mortality of 85% during childhood following the natural course, over 85% of these infants are now expected to reach adulthood. However, data on long-term outcome is scarce due to the lack of large, national registries. Moreover, little is known about the genetic basis of congenital heart defects. In 2000, the Interuniversity Cardiology Institute of the Netherlands and the Netherlands Heart Foundation have taken the initiative to develop a national registry and DNA-bank of patients with congenital heart disease in the Netherlands named CONCOR.

OBJECTIVES

The aims of the CONCOR project are to facilitate investigation of the prevalence and long-term outcome of specific congenital heart defects and their treatment, to develop an efficient organisational structure for the improvement of healthcare for patients with congenital heart disease, and to allow investigation of the molecular basis of congenital heart defects.

METHODS

After informed consent, research nurses enter data of participating patients into the CONCOR database using a web application. Data is transferred over the Internet via a secure connection. About 20 ml blood is withdrawn from the patient, and the DNA is isolated and stored. From each participating patient family history on congenital heart disease is obtained.

RESULTS

Within two and a half years more than 4200 patients have agreed to participate. More than 99% of the patients that were asked have given their consent to participate in CONCOR. From 60% of these patients DNA has already been obtained. Mean age of the patients included is 34 years; more than 85% of the patients are younger than 45 years. Late complications occur frequently and the incidence increases with advancing age. 18% of the patients are known with supraventricular or ventricular arrhythmias. 2% of the included patients suffered a cerebrovascular accident, 139 (3%) had endocarditis. 6% of the patients has pulmonary hypertension or Eisenmenger syndrome. More than 15% of the patients reported an affected family member with congenital heart disease in the first, second, or third degree. 6% has an affected first-degree relative, and 4% a second-degree relative. Already 10 research projects have started using the CONCOR data and DNA.

CONCLUSION

The population of patients with congenital heart disease is young and rapidly growing. Late complications occur frequently and the incidence increases with advances age. The CONCOR registry and DNA-bank facilitates research on prevalence and long-term outcome and allows investigation of the molecular basis of congenital heart disease.

High association of congenital heart disease with indirect inguinal hernia

We evaluated 103 patients with indirect inguinal hernia (IIH) for the association of congenital heart disease by echocardiography. Congenital cardiac abnormalities were recognized in 32% of patients with inguinal hernia, which is significantly higher than that reported in a population-based study in Turkey and other population-based studies. Ventricular septal defect and valvular anomalies are the most frequently detected malformations. Our findings suggest that screening for congenital hearth disease is necessary in children with indirect inguinal hernia.

A population-based study of extra-cardiac anomalies in children with congenital cardiac malformations

We describe the prevalence of extra-cardiac anomalies in children with congenital cardiac malformations, and their impact on survival, compared to the outcome in children with the congenital cardiac lesions as the only recognised anomaly. Our population comprises the 3527 children born with congenital cardiac anomalies between 1990 and 1999, and registered at the largest tertiary centre for Paediatric Cardiology in Norway. Extra-cardiac anomalies were found in one-fifth of the population, with Down's syndrome accounting for nearly one-third. Survival improved for children born between 1995 and 1999 compared with those born in the period from 1990 to 1994 for all groups, except for children with additional extra-cardiac anomalies in the absence of Down's syndrome. The results were the same for children undergoing surgical treatment of their cardiac malformation. The survival in children with Down's syndrome improved in comparable fashion to those without extra-cardiac anomalies. Children with extra-cardiac anomalies in the absence of Down's syndrome represent a heterogeneous group, with varying patterns of survival. Survival did not improve in these latter patients during the period of our study.

Parental decision-making in congenital heart disease

OBJECTIVE

To explore whether prenatal diagnosis of congenital heart disease is associated with lower levels of parental distress and greater satisfaction with decisions about cardiothoracic surgery when compared to postnatal diagnosis.

METHODOLOGY

A combined quantitative-qualitative design was used. Participants included the parents of 31 neonates (30 mothers and 22 fathers) admitted to the cardiac intensive care unit between 1 November 2001 and 1 May 2002 for repair of congenital cardiac malformations. Participants completed self-report measures of anxiety, optimism, and life events pre-operatively, and semi-structured qualitative interviews assessing satisfaction with decision-making within 1 week of the operation.

RESULTS

At the time of surgery, mothers of neonates receiving the diagnosis prenatally did not differ from mothers of neonates receiving the diagnosis postnatally on measures of anxiety, optimism, and life events. Fathers of neonates receiving the diagnosis prenatally, however, reported more optimism, lower state and trait anxiety, and fewer negative life events than fathers of neonates receiving the diagnosis postnatally. When we analyzed the interviews, we found that, regardless of the timing of the diagnosis, parents felt as though they made a genuine choice for their baby to have surgery.

CONCLUSIONS

In this pilot study, fathers who learned prenatally that their child had a congenital cardiac malformation were less distressed than those who discovered this fact only postnatally. From the parental perspective, nonetheless, distress and urgency do not impair their ability to make decisions about neonatal cardiac surgery.