Frequency of 22q11 deletions in patients with conotruncal defects

Velo-Cardio-Facial Syndrome

Velocardiofacial syndrome (VCFS) also known as DiGeorge, conotruncal anomaly face and Cayler syndromes is caused by a microdeletion in the long arm of chromosome 22. We review the history of the syndrome from the first clinical reports almost half a century ago to the current intriguing molecular findings associating genes from the microdeletion region and the physical and neuropsychiatric phenotype of the syndrome. Velocardiofacial syndrome has a wide spectrum of more than 200 physical manifestations including palate and cardiac anomalies. Yet, the most challenging manifestations of VCFS are the learning disabilities and neuropsychiatric disorders. As VCFS is relatively common and as up to one third of the subjects with VCFS develop schizophrenia like psychotic disorder the syndrome is the most commonly known genetic risk factor to schizophrenia. Identifying the genetic, cognitive and psychiatric risk factors for VCFS-schizophrenia is under the focus of intensive research.

Identification of candidate genes for congenital ventricular septal defects with HSA22q11 loss of heterozygosity

INTRODUCTION AND OBJECTIVES

Ventricular septal defect (VSD) is one of the major forms of congenital heart disease (CHD) in individuals with Homo sapiens chromosome 22q11 (HSA22q11) deletion syndrome. The objective was to identify candidate genes associated with VSD located within HSA22q11 by analyzing loss of heterozygosity (LOH) using microsatellite genotyping and by gene dosage analysis in seven candidate genes.

METHODS

The study involved 82 families with CHD, which included 261 individuals (85 patients and 176 siblings and parents). All were screened for LOH in the HSA22q11 region by microsatellite (n=10) genotyping. Bioinformatic strategies were used to characterize seven candidate genes located within this region in greater detail. Quantitative polymerase chain reaction analysis was used to determine the dosages of the seven candidate genes in 16 patients with LOH of HSA22q11.

RESULTS

Overall, 42 out of 85 patients (49.4%) with CHD had at least one LOH in the HSA22q11 region. Moreover, LOH of HSA22q11 was found in 17 out of 29 patients with a VSD and in three out of four families with two offspring affected by CHD. Dosage analysis of the seven candidate genes showed recurrent heterozygous deletion of HIRA, GNB1L and TUBA8 genes in 16 VSD patients with a LOH of HSA22q11.

CONCLUSIONS

Microsatellite genotyping identified LOH of HSA22q11 in several types of CHD. Heterozygous deletion of HIRA, GNB1L or TUBA8 genes might play an important role in ventricular septum development. Since CHD can be a familial disease, screening the siblings of a proband for LOH of HSA22q could be valuable for early diagnosis and treatment.

Anomalous ascending aorta causing severe compression of the left bronchus in an infant with ventricular septal defect and pulmonary atresia

Tracheobronchial compression by cardiovascular structures complicates the course after surgery of congenital heart disease. A 2-month-old boy with ventricular septal defect, pulmonary atresia, and velocardiofacial syndrome had severe left main bronchus obstruction due to external compression by an anomalously oriented ascending aorta. The patient's hypoxemic episodes necessitated extracorporeal membrane oxygenation. We inserted a stent in the left bronchus to open the airway, but the stent was crushed by the anomalous aorta. We later surgically rerouted the aorta and finally restored the patency of the left main bronchus. However, the patient died of fungemia, without being weaned from extracorporeal membrane oxygenation. We conclude that surgery is necessary instead of stent implantation to relieve the external compression of the left bronchus from a vessel with systemic arterial pressure.

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.

Chromosomal abnormalities among children born with conotruncal cardiac defects

BACKGROUND

Conotruncal heart defects compose 25% to 30% of nonsyndromic congenital heart defects. This study describes the frequency of chromosome abnormalities and microdeletion of 22q11 associated among infants and fetuses delivered with conotruncal heart malformations.

METHODS

From a population base of 974,579 infants/fetuses delivered, 622 California infants/fetuses were ascertained with a defect of aortopulmonary septation. Infants whose primary cardiac defect was tetralogy of Fallot (n = 296) or d-transposition of the great arteries (n = 189) were screened for microdeletion of 22q11.

RESULTS

Of the infants who had routine karyotypes, 5% had chromosomal abnormalities, including four with extra sex chromosomes. Thirty infants had chromosome 22q11 microdeletions, providing a cause for 10% of infants whose primary defect was tetralogy of Fallot. Right aortic arch, abnormal branching patterns of the major arteries arising from the thoracic aorta, and pulmonary artery abnormalities were observed more frequently among infants with tetralogy of Fallot caused by 22q11 microdeletion.

CONCLUSIONS

We found an unusual number of infants with an extra sex chromosome and a conotruncal defect. Infants with tetralogy of Fallot owing to 22q11 microdeletion showed more associated vascular anomalies than infants with tetralogy without a 22q11 microdeletion. Although these associated vascular anomalies provide clues as to which infants with tetralogy of Fallot are more likely to carry the microdeletion, the overall risk of 10% among infants with tetralogy of Fallot warrants chromosome analysis and fluorescent in situ hybridization (FISH) testing routinely, which may be supplanted by genome-wide copy number testing as it becomes more widely utilized.

An infant with transposition and cystic fibrosis

We report an infant with transposition, with the circumflex artery arising from the right coronary artery, who was diagnosed with cystic fibrosis following the occurrence of meconium ileus in the postoperative period.

Variants of folate metabolism genes and the risk of conotruncal cardiac defects

BACKGROUND

Although congenital heart defects (CHD) are the most common and serious group of birth defects, relatively little is known about the causes of these conditions and there are no established prevention strategies. There is evidence suggesting that the risk of CHD in general, and conotruncal and ventricular septal defects in particular, may be related to maternal folate status as well as genetic variants in folate-related genes. However, efforts to establish the relationships between these factors and CHD risk have been hampered by a number of factors including small study sample sizes and phenotypic heterogeneity.

METHODS AND RESULTS

The present study examined the relationships between variation in 9 folate-related genes and a subset of CHD phenotypes (ie, conotruncal defects, perimembranous and malalignment type ventricular septal defects, and isolated aortic arch anomalies) in a cohort of >700 case-parent triads. Further, both maternal and embryonic genetic effects were considered. Analyses of the study data confirmed an earlier reported association between embryonic genotype for MTHFR A1298C and disease risk (unadjusted P=0.002).

CONCLUSIONS

These results represent the most comprehensive and powerful analysis of the relationship between CHD and folate-related genes reported to date, and provide additional evidence that, similar to neural tube defects, this subset of CHD is folate related.

Cardiac defects and results of cardiac surgery in 22q11.2 deletion syndrome

Specific types and subtypes of cardiac defects have been described in children with 22q11.2 deletion syndrome as well as in other genetic syndromes. The conotruncal heart defects occurring in patients with 22q11.2 deletion syndrome include tetralogy of Fallot, pulmonary atresia with ventricular septal defect, truncus arteriosus, interrupted aortic arch, isolated anomalies of the aortic arch, and ventricular septal defect. These conotruncal heart defects are frequently associated in this syndrome with additional cardiovascular anomalies of the aortic arch, pulmonary arteries, infundibular septum, and semilunar valves complicating cardiac anatomy and surgical treatment. In this review we describe the surgical anatomy, the operative treatment, and the prognostic results of the cardiac defects associated with 22q11.2 deletion syndrome. According to the current literature, in patients with tetralogy of Fallot with/without pulmonary atresia and truncus arteriosus, in spite of the complex cardiac anatomy, the presence of 22q11.2 deletion syndrome does not worsen the surgical prognosis. On the contrary in children with pulmonary atresia with ventricular septal defect and probably in those with interrupted aortic arch the association with 22q11.2 deletion syndrome is probably a risk factor for the operative treatment. The complex cardiovascular anatomy in association with depressed immunological status, pulmonary vascular reactivity, neonatal hypocalcemia, bronchomalacia and broncospasm, laryngeal web, and tendency to airway bleeding must be considered at the time of diagnosis and surgical procedure. Specific diagnostic, surgical, and perioperative protocols should be applied in order to provide appropriate treatment and to reduce surgical mortality and morbidity.

Genetic counseling for the 22q11.2 deletion

Because of advances in palliative medical care, children with the 22q11.2 deletion syndrome are surviving into adulthood. An increase in reproductive fitness will likely follow necessitating enhanced access to genetic counseling for these patients and their families. Primary care physicians/obstetric practitioners are in a unique position to identify previously undiagnosed patients as they reach reproductive age and to refer them for genetic counseling. To date, most deletions are de novo, secondary to homologous recombination between low-copy repeat sequences located within 22q11.2. Nonetheless, both somatic and germ line mosaicism has been observed giving unaffected parents a small risk of recurrence. Once present though there is a 50% chance for a person with this contiguous deletion to have an affected child. With this in mind, a variety of prenatal monitoring techniques, as well as, preimplantation genetic diagnosis are available depending on the specific level of risk.

Chromosome 22q11.2 microdeletion in children with conotruncal heart defects: frequency, associated cardiovascular anomalies, and outcome following cardiac surgery

The association of conotruncal heart defects with 22q11.2 chromosomal microdeletions is well established. However, it is not clear whether particular types of conotruncal malformations or additional cardiovascular anomalies are associated with microdeletions. In addition, cardiac surgery outcome in children with conotruncal defects and del22q11.2 is not well described. We prospectively enrolled 214 children with conotruncal defects: 126 with tetralogy of Fallot (TOF), 18 with pulmonary atresia-ventricular septal defect (PA-VSD), 15 with truncus arteriosus communis (TAC) type I, one with interrupted aortic arch (IAA) type B, and 54 with the transposition of great arteries, who were consecutively hospitalized at the Pediatric Cardiology Department between 2003 and 2005. 22q11.2 microdeletion was identified by fluorescence in situ hybridization. The postoperative course following cardiac surgery was compared in patients with TOF and its more severe form, PA-VSD, with/without del22q11.2 (groups A and B) and TAC with/without del22q11.2 (groups C and D). In 15 of 214 patients, 22q11.2 microdeletion was diagnosed (in 11 with TOF/PA-VSD, in three with TAC, in one with IAA type B). In patients with TOF/PA-VSD and microdeletion anatomic features that were significantly associated with 22q11.2, deletion included right aortic arch (p = 0.018), aberrant right subclavian artery (p < 0.001), and major aortopulmonary collateral arteries (p = 0.016). A complicated postoperative course was more frequent and mortality was higher in patients with conotruncal defects and with/without microdeletion. We conclude that additional cardiovascular anomalies are significantly more frequent in children with 22q11.2 microdeletion and TOF/PA-VSD. Children with conotruncal heart defects and 22q11.2 microdeletion more frequently experienced complicated postoperative course after cardiac surgery.

A rare association of interrupted aortic arch type C and microdeletion 22q11.2

Microdeletion 22q11.2 is associated with a variety of findings, and the most common are cardiac defects. It is very frequently associated with interrupted aortic arch (IAA) type B and very rarely with type A and type C. Here we report the first case of IAA type C associated with 22q11.2 deletion in Serbia and, to the best of our knowledge, the fourth case described worldwide so far. By this report we would like to point out that all patients with IAA type C who have additional features specific for 22q11.2 microdeletion syndrome should be screened for the presence of this deletion.

Adults with genetic syndromes and cardiovascular abnormalities: clinical history and management

Cardiovascular abnormalities, especially structural congenital heart defects, commonly occur in malformation syndromes and genetic disorders. Individuals with syndromes comprise a significant proportion of those affected with selected congenital heart defects such as complete atrioventricular canal, interrupted arch type B, supravalvar aortic stenosis, and pulmonary stenosis. As these individuals age, they contribute to the growing population of adults with special health care needs. Although most will require longterm cardiology follow-up, primary care providers, geneticists, and other specialists should be aware of (1) the type and frequency of cardiovascular abnormalities, (2) the range of clinical outcomes, and (3) guidelines for prospective management and treatment of potential complications. This article reviews fundamental genetic, cardiac, medical, and reproductive issues associated with common genetic syndromes that are frequently associated with a cardiovascular abnormality. New data are also provided about the cardiac status of adults with a 22q11.2 deletion and with Down syndrome.

Frequency of 22q11.2 microdeletion in sporadic non-syndromic tetralogy of Fallot cases

BACKGROUND

Tetralogy of Fallot (TOF) is a congenital conotruncal heart defect commonly found in DiGeorge (DGS) and velocardiofacial (VCFS) syndromes. The deletion of chromosome 22q11 has also been demonstrated in sporadic or familial cases of TOF. The aim of the present study was to investigate the frequency of del22q11 in patients with non-syndromic TOF seen at a tertiary Pediatric Cardiology care center.

METHOD

One hundred and twenty three non-syndromic TOF patients were selected and evaluated by history, physical examination and review of medical records. Venous blood was drawn for genomic DNA extraction after informed consent 22q11 microdeletion diagnosis was conducted through a standardized SNP genotyping assay and consecutive homozygosity mapping. Phenotype-genotype correlations regarding cardiac anatomy were conducted.

RESULTS

We evaluated 123 non-syndromic TOF patients for a 22q11 deletion. 105 (85.4%) patients presented pulmonary stenosis and 18 (14.6%) had pulmonary atresia. Eight patients (6.5%) were found to have a deletion. Of the deleted patients, three (37.5%) presented pulmonary atresia. We have verified a tendency towards a higher prevalence of pulmonary atresia when comparing TOF patients with and without 22q11 microdeletion.

CONCLUSIONS

22q11.2 deletion in non-syndromic TOF patients is present in approximately 6% of patients. We suggest a tendency towards a higher prevalence of pulmonary atresia in non-syndromic TOF patients with 22q11 microdeletion. Molecular genetic screening of non-syndromic TOF patient may be important for the correct care of these patients and a more specific genetic diagnostic and counseling.

Controversies in pregnancy and congenital heart disease

As increasing numbers of children with congenital heart disorders reach adulthood, the family physician, cardiologist, and obstetrician will increasingly be called upon to give advice regarding the safety of pregnancy. This need has been further highlighted by the recognition that maternal mortality associated with cardiac disease is rising. Unfortunately, this field of practice remains relatively "evidence-sparse" with many management decisions being guided by anecdote and "best guess" common sense. Not surprisingly, this results in many fundamental controversies over the optimal care these patients should receive. This article highlights, through the use of case histories, some of these contentious areas, reflecting the different manifestations of congenital maternal cardiac disease and highlighting the limitations of our knowledge.

Biobanks and biomarker research in cardiovascular disease

PURPOSE

The purpose of this article is to describe biobank processes and the sociocultural and nursing challenges of these processes. The article will present ways that thinking genetically can challenge cardiovascular nurses and help in the development of biobanks for cardiovascular research. It will emphasize the importance of the contributions of nursing to the development of biobanks and biobanking research.

CONCLUSIONS

The influence of cardiovascular nurses on the development of biobanks for research in cardiovascular disease will result in accelerated discoveries that will lead to innovative, safe, effective therapeutics (translational research and personalized healthcare). The challenge is to educate and encourage clinicians to think genetically and use biobanks for research.

Ethical issues raised by incorporation of genetics into the National Birth Defects Prevention Study

Investigators involved in public health research must conduct high-quality studies that advance scientific knowledge for the collective benefit of the public's health, while at the same time ensuring that the individual rights of human subjects are protected. Successful completion of the Human Genome Project provides greater opportunity to incorporate the study of genetic factors into public health research. Integration of DNA specimen collection into epidemiological studies of complex disorders, such as birth defects, is necessary to identify genetic risk factors that affect susceptibility to potentially modifiable environmental risk factors, but collection of DNA samples often heightens concerns about ethical issues. Some of these issues include ensuring informed consent in an ongoing study as new genetic risk factors and novel genetic technologies for study continue to be identified, achieving a balance between improving participation using incentives and avoiding coercion, ensuring confidentiality of individual genetic data, and considering when and how to report research results to study participants. We present a discussion of ethical issues addressed by investigators of the National Birth Defects Prevention Study, a multisite, population-based, case-control study of risk factors for birth defects, which has incorporated the study of genetic risk factors. Study participants include infants and young children whose parents consent on their behalf, increasing the complexity of the ethical issues. Discussion of these issues and the methods employed to ensure protection of human subjects might be helpful to other investigators working to integrate genetics into large epidemiological studies.

Frequency of aberrant subclavian artery, arch laterality, and associated intracardiac anomalies detected by echocardiography

Tetralogy of Fallot is generally considered to be the most common congenital heart defect associated with an aberrant subclavian artery (ASA), but the prevalence of ASA in patients with other cardiac anomalies is not well described. The pediatric echocardiography database, with 15,871 initial echocardiograms, was searched for all patients with ASA. Arch laterality and associated intracardiac anomalies were documented for each patient. ASA was found in 226 patients, of whom 171 had a left aortic arch (LAA) and 55 had a right aortic arch (RAA). The occurrence of ASA was 1% in patients with LAA (171 of 15,650) and 25% in patients with RAA (55 of 221; p = 0.001). Intracardiac anatomy was normal in 32% of patients with ASA/LAA and 25% with ASA/RAA. Conotruncal anomalies occurred more frequently with ASA/RAA than ASA/LAA (36% vs 18%; p = 0.01). Atrioventricular canal defects accounted for 10% and left-sided cardiac obstructive lesions accounted for 11% of subjects with ASA/LAA. ASA was rarely associated with d-transposition of the great arteries (1 of 226) and double-outlet right ventricle (5 of 226). The prevalence of ASA was highest in patients with interrupted aortic arch (11 of 38; 29%). In patients with tetralogy of Fallot, the overall prevalence of ASA was 8% (34 of 447), but was higher with RAA (16 of 103; 16%). The highest prevalence of ASA occurred in the subgroup of patients with tetralogy of Fallot with pulmonary atresia and RAA (6 of 25; 24%). In conclusion, ASA was more common in patients with RAA, especially with conotruncal anomalies. In patients with LAA, hypoplastic left heart syndrome, aortic coarctation, and atrioventricular canal defects were commonly associated with ASA.

GATA4 sequence variants in patients with congenital heart disease

BACKGROUND

Recent reports have identified mutations in the transcription factor GATA4 in familial cases of cardiac septal defects. The prevalence of GATA4 mutations in the population of patients with septal defects is unknown. Given that patients with septal and conotruncal defect can share a common genetic basis, it is unclear whether patients with additional types of CHD might also have GATA4 mutations.

AIMS

To explore these questions by investigating a large population of 628 patients with either septal or conotruncal defects for GATA4 sequence variants.

METHODS

The GATA4 coding region and exon-intron boundaries were investigated for sequence variants using denaturing high-performance liquid chromatography or conformation-sensitive gel electrophoresis. Samples showing peak or band shifts were reamplified from genomic DNA and sequenced.

RESULTS

Four missense sequence variants (Gly93Ala, Gln316Glu, Ala411Val, Asp425Asn) were identified in five patients (two with atrial septal defect, two with ventricular septal defect and one with tetralogy of Fallot), which were not seen in a control population. All four affected amino acid residues are conserved across species, and two of the sequence variants lead to changes in polarity. Ten synonymous sequence variants were also identified in 18 patients, which were not seen in the control population.

CONCLUSIONS

These data suggest that non-synonymous GATA4 sequence variants are found in a small percentage of patients with septal defects and are very uncommonly found in patients with conotruncal defects.

Extracardiac features predicting 22q11.2 deletion syndrome in adult congenital heart disease

BACKGROUND AND OBJECTIVES

22q11.2 Deletion Syndrome (22q11.2DS) is an important genetic syndrome to cardiologists yet remains under-recognized in adults. There is no evidence-based guideline for genetic testing referrals. Feasibility issues in many jurisdictions preclude testing for 22q11.2 deletions in every congenital cardiac patient. We aimed to determine an optimal combination of extracardiac features that could be clinically helpful in identifying adults with tetralogy of Fallot (TOF) and related conotruncal anomalies at highest risk for 22q11.2DS.

METHODS

Adults (n=103) at a congenital cardiac clinic (86 with TOF) had a brief clinical screening assessment and genetic testing for 22q11.2 deletions using standard fluorescence in-situ hybridization; 31 had a 22q11.2 deletion. Discriminant ability (DA), defined as (sensitivity+specificity)/2, was used to measure performance of 18 (17 clinical and one demographic) features in predicting 22q11.2DS (DA>80%=a good screening test).

RESULTS

Combining two features was required for a good test: a global impression of 22q11.2DS dysmorphic facies, with either learning difficulties (DA=82.4%) or voice abnormalities such as hypernasality (DA=81.6%). A four-feature combination (suggestive dysmorphic facies, voice abnormalities, learning difficulties and age <30 years) yielded maximal sensitivity (100%) and DA>85% at a cut-off of three features. Neither rates of right aortic arch or cardiac surgery differed between patients with and without 22q11.2 deletions.

CONCLUSIONS

Clinicians who consider as few as two extracardiac features readily detectable in a brief clinical encounter could help identify those with 22q11.2DS among adults with congenital heart disease. Diagnosis of 22q11.2DS is important for optimizing management of these complex patients.

22q11.2 distal deletion: a recurrent genomic disorder distinct from DiGeorge syndrome and velocardiofacial syndrome

Microdeletions within chromosome 22q11.2 cause a variable phenotype, including DiGeorge syndrome (DGS) and velocardiofacial syndrome (VCFS). About 97% of patients with DGS/VCFS have either a common recurrent approximately 3 Mb deletion or a smaller, less common, approximately 1.5 Mb nested deletion. Both deletions apparently occur as a result of homologous recombination between nonallelic flanking low-copy repeat (LCR) sequences located in 22q11.2. Interestingly, although eight different LCRs are located in proximal 22q, only a few cases of atypical deletions utilizing alternative LCRs have been described. Using array-based comparative genomic hybridization (CGH) analysis, we have detected six unrelated cases of deletions that are within 22q11.2 and are located distal to the approximately 3 Mb common deletion region. Further analyses revealed that the rearrangements had clustered breakpoints and either a approximately 1.4 Mb or approximately 2.1 Mb recurrent deletion flanked proximally by LCR22-4 and distally by either LCR22-5 or LCR22-6, respectively. Parental fluorescence in situ hybridization (FISH) analyses revealed that none of the available parents (11 out of 12 were available) had the deletion, indicating de novo events. All patients presented with characteristic facial dysmorphic features. A history of prematurity, prenatal and postnatal growth delay, developmental delay, and mild skeletal abnormalities was prevalent among the patients. Two patients were found to have a cardiovascular malformation, one had truncus arteriosus, and another had a bicuspid aortic valve. A single patient had a cleft palate. We conclude that distal deletions of chromosome 22q11.2 between LCR22-4 and LCR22-6, although they share some characteristic features with DGS/VCFS, represent a novel genomic disorder distinct genomically and clinically from the well-known DGS/VCF deletion syndromes.

Adult congenital heart disease: a 2008 overview

INTRODUCTION

During the past decades, health care of patients born with congenital heart disease (CHD) has improved substantially, leading to a growing population of adult survivors.

SOURCE OF DATA

Using the recently published and relevant data on adult CHD (ACHD), we reviewed the most common congenital heart defects and discussed important related issues.

AREAS OF AGREEMENT

Adults with CHD most often require specialized medical or surgical care in a tertiary centre. However, this population also need local follow-up; general practitioners and other specialists therefore have to face the complexity of their disease. AREAS OF CONTROVERSIES: Management of pregnancy, non-cardiac surgery, arrhythmias and endocarditis prophylaxis may be challenging in patients with CHD and should be adapted to their condition.

GROWING POINTS

The present article summarizes key clinical information on ACHD for the benefit of physicians who are not specialized in this field. Areas timely for developing research Research efforts and education strategies are greatly needed in order to optimize the care of patients with ACHD.

Velo-cardio-facial syndrome: 30 Years of study

Velo-cardio-facial syndrome is one of the names that has been attached to one of the most common multiple anomaly syndromes in humans. The labels DiGeorge sequence, 22q11 deletion syndrome, conotruncal anomalies face syndrome, CATCH 22, and Sedlacková syndrome have all been attached to the same disorder. Velo-cardio-facial syndrome has an expansive phenotype with more than 180 clinical features described that involve essentially every organ and system. The syndrome has drawn considerable attention because a number of common psychiatric illnesses are phenotypic features including attention deficit disorder, schizophrenia, and bipolar disorder. The expression is highly variable with some individuals being essentially normal at the mildest end of the spectrum, and the most severe cases having life-threatening and life-impairing problems. The syndrome is caused by a microdeletion from chromosome 22 at the q11.2 band. Although the large majority of affected individuals have identical 3 megabase deletions, less than 10% of cases have smaller deletions of 1.5 or 2.0 megabases. The 3 megabase deletion encompasses a region containing 40 genes. The syndrome has a population prevalence of approximately 1:2,000 in the United States, although incidence is higher. Although initially a clinical diagnosis, today velo-cardio-facial syndrome can be diagnosed with extremely high accuracy by fluorescence in situ hybridization and several other laboratory techniques. Clinical management is age dependent with acute medical problems such as congenital heart disease, immune disorders, feeding problems, cleft palate, and developmental disorders occupying management in infancy and preschool years. Management shifts to cognitive, behavioral, and learning disorders during school years, and then to the potential for psychiatric disorders including psychosis in late adolescence and adult years. Although the majority of people with velo-cardio-facial syndrome do not develop psychosis, the risk for severe psychiatric illness is 25 times higher for people affected with velo-cardio-facial syndrome than that of the general population. Therefore, interest in understanding the nature of psychiatric illness in the syndrome remains strong.

Peri-operative management of paediatric patients undergoing cardiac surgery--focus on respiratory aspects of care

Children requiring cardiac surgery present particular challenges in peri-operative respiratory management. The wide variety of conditions and operations and their varied impact on respiratory function makes dialogue with related medical staff essential. In most circumstances, cardiac performance is the main determinant of respiratory outcomes. Changing cardiologic and surgical approaches have combined to diminish the severity and frequency of pulmonary hypertensive issues and new treatment modalities are simplifying the intensive care approach. Patients with Down's syndrome and 22q11 deletion syndrome present particular issues related to anatomy, physiology and respiratory function. Certain conditions, including tetralogy of Fallot and cavopulmonary connections, present unique circumstances where respiratory management, sometimes including extubation, may assist in optimisation of cardiac performance. These and other conditions highlight the complexities of cardiopulmonary interactions. Cardiac performance remains the principal determinant of outcome after paediatric cardiac surgery and has the biggest impact on respiratory function.

Velocardiofacial syndrome, DiGeorge syndrome: the chromosome 22q11.2 deletion syndromes

Velocardiofacial syndrome, DiGeorge syndrome, and some other clinical syndromes have in common a high frequency of hemizygous deletions of chromosome 22q11.2. This deletion syndrome is very common, affecting nearly one in 3000 children. Here, we focus on recent advances in cardiac assessment, speech, immunology, and pathophysiology of velocardiofacial syndrome. The complex medical care of patients needs a multidisciplinary approach, and every patient has his own unique clinical features that need a tailored approach. Patients with chromosome 22q11.2 deletion syndrome might have high level of functioning, but most often need interventions to improve the function of many organ systems.

Seeking causes: Classifying and evaluating congenital heart defects in etiologic studies

BACKGROUND

Classification and analysis of congenital heart defects (CHD) in etiologic studies is particularly challenging because of diversity of cardiac phenotypes and underlying developmental mechanisms. We describe an approach to classification for risk assessment of CHD based on developmental and epidemiologic considerations, and apply it to data from the National Birth Defect Prevention Study (NBDPS).

METHODS

The classification system incorporated the three dimensions of cardiac phenotype, cardiac complexity, and extracardiac anomalies. The system was designed to facilitate the assessment of simple isolated defects and common associations. A team with cardiologic expertise applied the system to a large sample from the NBDPS.

RESULTS

Of the 4,703 cases of CHDs in the NBDPS with birth years 1997 through 2002, 63.6% were simple, isolated cases. Specific associations of CHDs represented the majority of the remainder. The mapping strategy generated relatively large samples for most cardiac phenotypes and provided enough detail to isolate important subgroups of CHDs that may differ by etiology or mechanism.

CONCLUSIONS

Classification of CHDs that considers cardiac and extracardiac phenotypes is practically feasible, and yields manageable groups of well-characterized phenotypes. Although best suited for large studies, this approach to classification and analysis can be a flexible and powerful tool in many types of etiologic studies of heart defects.

Two-year general and neurodevelopmental outcome after neonatal complex cardiac surgery in patients with deletion 22q11.2: A comparative study

OBJECTIVE

Neonatal complex cardiac surgery carries a significant risk for adverse neurodevelopmental outcome. We hypothesized this risk to be higher in patients with deletion 22q11.2.

METHODS

From 1996 to 2004, neonates who had complex cardiac surgery at age 6 weeks or less had multisite, multidisciplinary health and neurodevelopmental outcomes (Bayley Scales of Infant Development II; mental and psychomotor developmental indices [MDI, PDI] as mean [SD] and delay [<70]) assessed at 18 to 24 months of age. All 16 patients with deletion 22q11.2 (group 1) were compared with 16 patients without deletion 22q11.2 (group 2) having undergone neonatal complex cardiac surgery at the same center and matched for cardiac lesion, socioeconomic status, and year of operation. Outcomes were compared by univariate and multivariate analyses.

RESULTS

Heart lesions in each group consisted of 6 (37.5%) cases of interrupted aortic arch, 6 (37.5%) cases of truncus arteriosus, and 4 (25%) cases of tetralogy of Fallot. Outcomes were available for all survivors. Mortality was 3 (19%) and 1 (6%) in groups 1 and 2, respectively (P = .6). MDI and PDI scores were 66.1 (10.6) and 55.0 (9.4) for group 1 and 86.3 (14.6) and 82.3 (14.3) for group 2 (P < .001). Only deletion 22q11.2 was significant in stepwise multiple regression to predict MDI and PDI scores. Mental delay occurred in 8 (61.5%) of 13 in group 1 and 2 (13.8%) of 15 in group 2 (P = .016). Psychomotor delay occurred in 11 (84.6%) of 13 in group 1 and 1 (6.7%) of 15 in group 2 (P < .001).

CONCLUSION

Neonates affected by deletion 22q11.2 and having neonatal complex cardiac surgery have significantly worse neurodevelopmental outcome than do those without deletion 22q11.2.

Severe Pregnancy-Induced Deterioration of Truncal Valve Regurgitation in an Adolescent Patient with Repaired Truncus Arteriosus

Truncus arteriosus, a rare and complex congenital heart disease, is hallmarked by a single great vessel (truncus) that arises over a large ventricular septal defect and provides both the pulmonary and systemic circulation. Pregnancy reports after repair for truncus arteriosus are scarce. Therefore, the maternal and offspring outcomes are unknown. We report the outcome of a pregnancy in an 18-year-old woman with repaired truncus arteriosus. Despite severe and symptomatic deterioration of truncal valve regurgitation, she successfully delivered a healthy child, and the valve function recovered within 2 weeks postpartum.

Neural crest contribution to the cardiovascular system

Normal cardiovascular development requires complex remodeling of the outflow tract and pharyngeal arch arteries to create the separate pulmonic and systemic circulations. During remodeling, the outflow tract is septated to form the ascending aorta and the pulmonary trunk. The initially symmetrical pharyngeal arch arteries are remodeled to form the aortic arch, subclavian and carotid arteries. Remodeling is mediated by a population of neural crest cells arising between the mid-otic placode and somite four called the cardiac neural crest. Cardiac neural crest cells form smooth muscle and pericytes in the great arteries, and the neurons of cardiac innervation. In addition to the physical contribution of smooth muscle to the cardiovascular system, cardiac neural crest cells also provide signals required for the maintenance and differentiation of the other cell layers in the pharyngeal apparatus. Reciprocal signaling between the cardiac neural crest cells and cardiogenic mesoderm of the secondary heart field is required for elaboration of the conotruncus and disruption in this signaling results in primary myocardial dysfunction. Cardiovascular defects attributed to the cardiac neural crest cells may reflect either cell autonomous defects in the neural crest or defects in signaling between the neural crest and adjacent cell layers.

Genetic basis for congenital heart defects: current knowledge: a scientific statement from the American Heart Association Congenital Cardiac Defects Committee, Council on Cardiovascular Disease in the Young: endorsed by the American Academy of Pediatrics

The intent of this review is to provide the clinician with a summary of what is currently known about the contribution of genetics to the origin of congenital heart disease. Techniques are discussed to evaluate children with heart disease for genetic alterations. Many of these techniques are now available on a clinical basis. Information on the genetic and clinical evaluation of children with cardiac disease is presented, and several tables have been constructed to aid the clinician in the assessment of children with different types of heart disease. Genetic algorithms for cardiac defects have been constructed and are available in an appendix. It is anticipated that this summary will update a wide range of medical personnel, including pediatric cardiologists and pediatricians, adult cardiologists, internists, obstetricians, nurses, and thoracic surgeons, about the genetic aspects of congenital heart disease and will encourage an interdisciplinary approach to the child and adult with congenital heart disease.

Antenatal diagnosis of double outlet of right ventricle without extracardiac anomaly: a report of 4 cases

Four fetuses were diagnosed antenatally with double outlet of right ventricle (DORV) at 17, 20, 26, and 28 weeks' gestation, respectively, using 2-dimensional sonography. Chromosome study was normal in all 4 cases, and there were no extracardiac abnormalities. The sonographic diagnoses were based on the following findings: (1) arising of the 2 great vessels predominantly from the right ventricle; (2) the presence of bilateral coni; and (3) parallel direction of the 2 vessels rather than the normal perpendicular course. Two cases were terminated electively with postnatal autopsy confirmation; the other 2 cases were closely monitored throughout pregnancy and underwent normal vaginal delivery at term and subsequent surgical correction with good outcome. In conclusion, DORV can be readily diagnosed in utero by checking outflow tract even without 3-dimensional sonography and in the absence of obvious risk for congenital heart defects.

Immediate and long-term outcomes in children with prenatal diagnosis of selected isolated congenital heart defects

OBJECTIVES

To compare the immediate postinterventional and long-term outcomes of children with a prenatal and those with a postnatal diagnosis of isolated congenital heart defects.

METHODS

This was a retrospective study of 257 children admitted over a 10-year period to our pediatric cardiology unit with one of four different cardiac lesions: transposition of the great arteries, atrioventricular canal defect, tetralogy of Fallot and pulmonary atresia; 208 were diagnosed postnatally and 49 prenatally. Management was identical in the two patient groups.

RESULTS

The median age at admission was 22 days in the postnatal group and 10 days in the prenatal group. In the prenatal group there was a higher median preoperative O2 saturation level (P=0.07), fewer cases of preoperative cardiac failure (P=0.03), fewer cases of preoperative closure of the duct (P=0.04), a shorter median duration of postoperative mechanical ventilation (P=0.03), less need for resurgery (P=0.02) and a shorter median duration of stay in the intensive care unit (P=0.05). Postoperative survival was 96% in the prenatal group and 90% in the postnatal group. Assessment of long-term survival revealed a longer catheter intervention-free interval in the prenatal group (P=0.03). At the 1-year follow-up, residual impaired cardiac function was less frequent in the prenatal than in the postnatal group (P=0.04). Overall survival at maximum follow-up was 92% in the prenatal and 84% in the postnatal group.

CONCLUSIONS

Prenatal diagnosis of isolated congenital heart defects allows admission for surgery in a more stable condition and is associated with lower short-term and long-term morbidity and mortality.

Genetics of congenital heart diseases in syndromic and non-syndromic patients: new advances and clinical implications

Congenital heart defects (CHDs) are the most common birth defects in humans and over the last 20 years significant progress has been made in the understanding of the molecular and genetic determinants of an increasing number of CHDs. Fundamental to this progress has been the contribution of five fields of research: the epidemiological results of the Baltimore-Washington Infant Study (BWIS); the pathogenetic classification introduced by Clark; the Human Genome Project; genotype-phenotype correlation and familial recurrence studies; and transgenic animals. The recently advanced cytogenetic techniques can now detect subtle rearrangements in chromosomes, which may be overlooked by standard methods and, more recently, molecular instruments such as linkage analysis and positional cloning are being used to identify genes causing Mendelian monogenic syndromes with CHDs, such as Holt-Oram, Ellis-van Creveld and Noonan/LEOPARD syndromes. Finally, useful information is yet available with regard to genes causing isolated CHDs in individuals who do not have a genetic syndrome (an example is the mutation of NKX2.5 and GATA4 genes causing atrial septal defect). The future perspectives for the genetics of CHDs will involve three fields of interest: diagnosis; therapy; and prognosis.

Right aortic arch detected in fetal life

OBJECTIVE

To evaluate the prenatal distribution, associated conditions and outcome of the different types of right aortic arch (RAA) detected in fetal life.

METHODS

This was a retrospective review of all cases of RAA detected prenatally between 1998 and 2005 in two tertiary referral centers.

RESULTS

In the study period 71 cases of RAA were detected; 26 (37%) had RAA with aberrant left subclavian artery, 23 (32%) had RAA with mirror-image branching, 20 (28%) had RAA of unknown type and two (3%) had double aortic arch. While 20/26 cases with RAA and aberrant left subclavian artery were isolated findings, all 23 cases with RAA and mirror-image branching were associated with cardiac defects, namely tetralogy of Fallot (43%) or pulmonary atresia with ventricular septal defect (22%). Of the 20 cases with RAA, 19 of unknown type were associated with heterotaxy syndromes and had additional cardiac malformations and ambiguities of the situs. The two cases with DAA were isolated findings. Seven cases in our series (10%) had a microdeletion 22q11 and these were significantly associated with extracardiac malformations. The outcome in our series depended solely on the associated cardiac and extracardiac malformations, with the exception of one infant with isolated DAA, in whom a surgical correction was warranted.

CONCLUSIONS

RAA detected in fetal life is associated frequently with other cardiac/non-cardiac malformations, heterotaxy syndromes and microdeletions 22q11. The associated conditions vary depending on the branching type of the brachiocephalic vessels and the presence of extracardiac malformations.

Interrupted Aortic Arch and Aortic Atresia With Circle of Willis-Dependent Coronary Perfusion

We present a case of type B interrupted aortic arch and aortic atresia. This combination is usually incompatible with life. However, the presence of an aberrant right subclavian artery and enough blood flow through the circle of Willis allowed perfusion of the coronary arteries through retrograde carotid and aortic blood flow. A two-ventricular repair was successfully undertaken.

Magnetic Resonance Imaging Evaluation of Congenital Heart Disease: Conotruncal Anomalies

Conotruncal anomalies comprise a diverse group of congenital heart defects involving the outflow tracts of the heart and the great vessels, including tetralogy of Fallot, transposition of the great arteries, truncus arteriosus, interrupted aortic arch, and other anomalies. Cardiovascular magnetic resonance (CMR) imaging plays an increasingly important role in the evaluation of patients with these lesions. Advances in CMR allow comprehensive assessment of cardiovascular anatomy, ventricular function, flow, and myocardial perfusion and viability. This article reviews the clinical aspects and the application of CMR before and after surgery in key conotruncal anomalies.

The clinical, immunological, and molecular spectrum of chromosome 22q11.2 deletion syndrome and DiGeorge syndrome

PURPOSE OF REVIEW

New findings regarding the clinical manifestations and care of patients with DiGeorge syndrome or chromosome 22q11.2 deletion syndrome will be reviewed. Immunologists and primary care providers often are in a position to coordinate the complex care needs of these patients and an awareness of the clinical features is essential.

RECENT FINDINGS

DiGeorge syndrome typically occurs in association with a hemizygous deletion of chromosome 22q11.2. Approximately 5-10% of patients with the clinical entity of DiGeorge syndrome do not have the deletion. Recent evidence indicates that the T cell compartment in both patients with the deletion and patients with clinical DiGeorge syndrome without the deletion is less robust than is often indicated by standard T cell enumeration.

SUMMARY

This past year has seen a dramatic increase in our understanding of the clinical features of patients with the deletion. Advances in our understanding of the immunodeficiency have been particularly exciting and clinicians should be aware of the characteristics of the immunodeficiency and its changes with age.

Cardiovascular anomalies in patients with chromosome 22q11.2 deletion: a Korean multicenter study

BACKGROUND AND OBJECTIVES

The 22q11.2 deletion syndrome is reported with increasing frequency worldwide, and its clinical manifestations, including cardiovascular anomalies, appear to be more diverse than previously reported. The aim of this study was to determine the incidence and the pattern of cardiovascular anomalies in Korean patients with 22q11 deletion.

METHODS

This study involved six Korean institutions. We reviewed the clinical records of patients and confirmed the presence of 22q11.2 deletion by fluorescent in situ hybridization (FISH).

RESULTS

A total of 222 patients were examined and 190 (85.6%) patients had the cardiovascular abnormalities: 63.2% tetralogy of Fallot (TOF), 20.5% isolated ventricular septal defects (VSDs), 5.3% interrupted aortic arch type B (IAA B), 3.6% double outlet right ventricle (DORV), 3.6% atrial septal defects (ASDs) and 1.7% truncus arteriosus (TA). Of 168 patients with VSD, 69.6% had the perimembranous type, 11.9% the total conal defect type, 6.5% the subarterial type, 4.2% the muscular type and 1.2% the mixed type. A right aortic arch was observed in 50% of patients, and an aberrant subclavian artery was significantly more common with a right (30.9%) than a left (18.3%) aortic arch (p<0.05).

CONCLUSIONS

A wide variety of cardiovascular anomalies were present in Korean patients with the 22q11.2 deletion.

PCR screening for 22q11.2 microdeletion: Development of a new cost-effective diagnostic tool

BACKGROUND

Del22q11.2 syndrome is the most frequent known chromosomal microdeletion syndrome. Previous studies suggest that a substantial number of patients with congenital heart disease have a 22q11 deletion. The molecular diagnosis of Del22q11.2 is usually made by fluorescence in situ hybridization, an expensive and not widely available technique. We developed an efficient and cost-effective PCR SNP assay designed for the screening of 22q11.2 deletion through consecutive homozygosity.

METHODS

Through the screening of dbSNP we have selected SNP markers located in the 22q11.2 microdeleted region. Population heterozygosities were determined in 213 normal individuals. Designed assays consisted of PCR amplification followed by restriction enzyme digestion. Fragments generated were visualized on agarose gel and genotyped.

RESULTS

Selected markers were: rs5748411, rs2238778, rs4819523 and rs4680. All selected markers were localized in the 22q11.2 deleted region. Allele and genotype frequencies of all selected markers were under Hardy-Weinberg equilibrium. Selected SNPs were not in linkage disequilibrium. Predicted assay specificity was estimated to be 92.86% in the Brazilian population.

CONCLUSIONS

The use of consecutive homozygosity in this SNP-based diagnostic test may be used as a cost-effective tool in reference molecular genetics laboratories.