Frequency of a 22q11 deletion in patients with conotruncal cardiac malformations: a prospective study

Comparison of Postoperative, In-Hospital Outcomes After Complete Repair of Tetralogy of Fallot Between 22q11.2 Deletion Syndrome and Trisomy 21

22q11.2 deletion syndrome (22q11) and trisomy 21 (T21) are frequently associated with tetralogy of Fallot (TOF). We hypothesized that there are differences in postoperative length of stay (LOS) and occurrence of postoperative interventions after complete repair of TOF when comparing children with 22q11 to those with T21. Using the Pediatric Health Information System, we performed a retrospective cohort study of patients who underwent complete repair of TOF from 2004 to 2019. Three groups were identified: 22q11, T21, and controls (those without a coded genetic syndrome). Outcomes were postoperative LOS and composite occurrence (yes/no) of at least one postoperative intervention. Bivariate and multivariate comparisons were made among groups; odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using the control group as the comparator. There were 6924 subjects (n = 493 22q11, n = 455 T21, n = 5976 controls). In bivariate analysis, 22q11 was associated with a longer LOS compared to T21 (OR 2.37 [2.16, 2.60] vs. 1.25 [1.12, 1.39], p < 0.001), and 22q11 more often underwent postoperative intervention (OR 3.42 [CI 2.56, 4.57] vs. 1.38 [CI 0.91, 2.11]; p < 0.001). In multivariate analysis, 22q11 was also associated with longer LOS (adjusted OR 1.35 [1.26, 1.44] vs. 1.12 [1.04, 1.20]; p < 0.001), but there was no difference in the adjusted odds of postoperative intervention. Children with 22q11 are more likely to experience adverse outcomes after repair of TOF compared to those with T21; the differences are most pronounced for LOS.

Aorto-pulmonary window with absent ductus arteriosus-A case report

Aorto-pulmonary window (APW) is a rare congenital heart defect characterized by the connection between the ascending aorta and the pulmonary trunk before its bifurcation, just above the semilunar valves, due to the abnormal development of spiral septum. The short-axis echocardiographic view of the right ventricular outflow track, the three-vessel-view, and the three-vessel-trachea view are the key planes for prenatal diagnosis. We report a case of APW with absent ductus arteriosus in a monochorionic twin, detected by prenatal echocardiography. The diagnosis was confirmed postnatally and corrective surgery was performed at the age of 1 week. Prenatal diagnosis of APW is essential, since surgical correction early after birth is required to prevent congestive heart failure secondary to high pulmonary blood flow.

Anomalous Systemic Arterial Supply to the Lung: To Which Category Should This Belong?

BACKGROUND

The nomenclature of both intralobar pulmonary sequestration (ILS) and aortic origin of a pulmonary artery (AOPA) remains controversial. According to this review, both ILS and AOPA have an anomalous systemic arterial supply to all or part of the lung with venous drainage into the pulmonary veins, which leads to pulmonary hypertension, congestive heart failure, and fatal pulmonary haemorrhage. The purpose of this review was to consider whether these two rare congenital anomalies have similar anatomical, clinical and pathological characteristics.

METHODS

This review was conducted by researching relevant literature using PubMed and MEDLINE databases to January 2019. All researched literature was related to the anatomical, associated anomalies, pathophysiology and clinical features of the extralobar pulmonary sequestration (ELS), ILS, and AOPA, and the therapeutic method for ILS and AOPA.

RESULTS

Through research literature, it was found that ILS and AOPA may differ in terms of embryonic origin, but some of the anatomical, histopathological, physiological and clinical features of these two congenital malformations are similar. However, ELS and ILS have significant differences in their anatomical, histopathological, physiological, and clinical features.

CONCLUSIONS

This study proposes that ILS and AOPA could be classified as one single condition - systemic arterialisation of the lung - and further divided into three subtypes, namely: types I, II and III. This new classification nomenclature permits the appropriate change of novel surgical techniques, which obviate the need for lobectomy or segmentectomy in specific cases, thereby minimising fatal postoperative complications.

22q11.2 Deletion Status and Perioperative Outcomes for Tetralogy of Fallot with Pulmonary Atresia and Multiple Aortopulmonary Collateral Vessels

Deletion of 22q11.2 (del22q11) is associated with adverse outcomes in patients with tetralogy of Fallot (TOF). We sought to investigate its contribution to perioperative outcome in patients with a severe form of TOF characterized by pulmonary atresia (PA) or severe pulmonary stenosis (PS) and major aortopulmonary collateral arteries (MAPCAS). We conducted a retrospective review of patients with TOF/MAPCAS who underwent staged surgical reconstruction between 1995 and 2006. Groups were compared according to 22q11.2 deletion status using t-tests or the Wilcoxon Rank sum test. We included 26 subjects, 24 of whom survived the initial operation. Of those, 21 subjects had known deletion status and constitute the group for this analysis [15 with no deletion present (ND) and 6 del22q11 subjects]. There was no difference with respect to occurrence of palliative procedure prior to initial operation, or to timing of closure of the ventricular septal defect (VSD). Other than higher prevalence of prematurity (50%) in the del22q11 group versus no prematurity in the ND, the groups were comparable in terms of pre-operative characteristics. The intra- and post-operative course outcomes (length of cardiopulmonary bypass, use of vasopressors, duration of intensive care and length of hospital stay, tube-feeding) were also comparable. Although the del22q11 had longer mechanical ventilation than the ND, this difference was not significant [68 h (range 4-251) vs. 45 h (range 3-1005), p = 0.81]. In this detailed comparison of a small patient cohort, 22q11.2 deletion syndrome was not associated with adverse perioperative outcomes in patients with TOF, PA, and MAPCAS when compared to those without 22q11.2 deletion syndrome. These results are relevant to prenatal and neonatal pre-operative counseling and planning.

Identification of ZFPM2 mutations in sporadic conotruncal heart defect patients

Conotruncal heart defects (CTDs) are a group of cardiac malformations that involve outflow tract anomalies and the arterial pole of the heart. Recent reports have identified mutations in a number of genes associated with CTDs in human and animal models. ZFPM2 plays a role in cardiac development by acting as a transcriptional cofactor that interacts with GATA4. Because ZFPM2 was found to be important for cardiac development in a knockout mouse model, we screened for ZFPM2 mutations in 528 CTD patients. We identified six rare and nonsynonymous ZFPM2 variants, and this was the first time that five of these variants (R698Q, R736L, E1005K, T32A, and I488V) were reported in East Asians. Western blots showed that there was no significant difference in the protein expression of wild-type ZFPM2, ZFPM2R698Q, or ZFPM2R736L. A dual luciferase reporter assay demonstrated that both ZFPM2 mutants R698Q and R736L reduced GATA4-mediated transcription. However, when ZFPM2R698Q was co-transfected with GATA4, BNP promoter activity increased significantly, whereas co-transfection with ZFPM2R736L and GATA4 did not significantly increase BNP promoter activity. This suggests that the R698Q mutation may affect the ability of ZFPM2 to bind GATA4.

Etiology and clinical presentation of birth defects: population based study

Objective To assess causation and clinical presentation of major birth defects.Design Population based case cohort.Setting Cases of birth defects in children born 2005-09 to resident women, ascertained through Utah's population based surveillance system. All records underwent clinical re-review.Participants 5504 cases among 270 878 births (prevalence 2.03%), excluding mild isolated conditions (such as muscular ventricular septal defects, distal hypospadias).Main outcome measures The primary outcomes were the proportion of birth defects with a known etiology (chromosomal, genetic, human teratogen, twinning) or unknown etiology, by morphology (isolated, multiple, minors only), and by pathogenesis (sequence, developmental field defect, or known pattern of birth defects).Results Definite cause was assigned in 20.2% (n=1114) of cases: chromosomal or genetic conditions accounted for 94.4% (n=1052), teratogens for 4.1% (n=46, mostly poorly controlled pregestational diabetes), and twinning for 1.4% (n=16, conjoined or acardiac). The 79.8% (n=4390) remaining were classified as unknown etiology; of these 88.2% (n=3874) were isolated birth defects. Family history (similarly affected first degree relative) was documented in 4.8% (n=266). In this cohort, 92.1% (5067/5504) were live born infants (isolated and non-isolated birth defects): 75.3% (4147/5504) were classified as having an isolated birth defect (unknown or known etiology).Conclusions These findings underscore the gaps in our knowledge regarding the causes of birth defects. For the causes that are known, such as smoking or diabetes, assigning causation in individual cases remains challenging. Nevertheless, the ongoing impact of these exposures on fetal development highlights the urgency and benefits of population based preventive interventions. For the causes that are still unknown, better strategies are needed. These can include greater integration of the key elements of etiology, morphology, and pathogenesis into epidemiologic studies; greater collaboration between researchers (such as developmental biologists), clinicians (such as medical geneticists), and epidemiologists; and better ways to objectively measure fetal exposures (beyond maternal self reports) and closer (prenatally) to the critical period of organogenesis.

Effect of 22q11.2 deletion on bleeding and transfusion utilization in children with congenital heart disease undergoing cardiac surgery

BACKGROUND

Postsurgical bleeding causes significant morbidity and mortality in children undergoing surgery for congenital heart defects (CHD). 22q11.2 deletion syndrome (DS) is the second most common genetic risk factor for CHD. The deleted segment of chromosome 22q11.2 encompasses the gene encoding glycoprotein (GP) Ibβ, which is required for expression of the GPIb-V-IX complex on the platelet surface, where it functions as the receptor for von Willebrand factor (VWF). Binding of GPIb-V-IX to VWF is important for platelets to initiate hemostasis. It is not known whether hemizygosity for the gene encoding GPIbβ increases the risk for bleeding following cardiac surgery for patients with 22q11.2 DS.

METHODS

We performed a case-control study of 91 pediatric patients who underwent cardiac surgery with cardiopulmonary bypass from 2004 to 2012 at Children's Hospital of Wisconsin.

RESULTS

Patients with 22q11.2 DS had larger platelets and lower platelet counts, bled more excessively, and received more transfusion support with packed red blood cells in the early postoperative period relative to control patients.

CONCLUSION

Presurgical genetic testing for 22q11.2 DS may help to identify a subset of pediatric cardiac surgery patients who are at increased risk for excessive bleeding and who may require more transfusion support in the postoperative period.

Surgical Results of Anomalous Origin of One Pulmonary Artery Branch from the Ascending Aorta

We reviewed our surgical experience with anomalous origin of one pulmonary artery from the ascending aorta (AOPA). From 1989 to 2012, 12 children (five neonates) aged 3-734 days (mean 152 ± 222) with AOPA underwent operations. Eight patients had right AOPA, and four patients had left AOPA. The majority of the patients had elevated right ventricular pressure, with 58 % (7 of 12) demonstrating suprasystemic right ventricular pressure. Surgery was performed by direct anastomosis (group 1) in seven patients and by employing an autologous patch (group 2) in five patients. There were two postoperative mortalities caused by heart failure and pulmonary hypertensive crisis. The mean follow-up duration was 12.6 ± 8 years. Catheterization showed that the right ventricle-to-systemic pressure ratio decreased following operation (preoperative vs. postoperative; 1.13 ± 0.19 vs. 0.48 ± 0.03, p = 0.043). There was no difference in the perfusion of the affected lung as measured by the final lung perfusion scan, between the two groups (group 1 vs. group 2; 50.0 ± 10.3 vs. 42.7 ± 28.7 %, p = 0.158). Two patients required reoperations for pulmonary regurgitation and pulmonary artery stenosis. There were two catheter-based interventions. At 20 years, survival by the Kaplan-Meier was 91.7 ± 8.0 %, freedom from reoperation was 80.0 ± 17.9 %, and freedom from catheter intervention was 80.8 ± 12.2 %. Early repair of AOPA improves right ventricular pressure and overall hemodynamics with excellent survival and low risk of reintervention. The type of surgical repair did not significantly affect the long-term outcomes (measured via lung perfusion scan).

22q11.2 deletion syndrome as a risk factor for aortic root dilation in tetralogy of Fallot

BACKGROUND

Aortic root dilation has been observed in some patients with tetralogy of Fallot. This study examines whether 22q11.2 deletion is a risk factor for aortic root dilation in tetralogy of Fallot.

METHODS

Patients with tetralogy of Fallot, in the age group of 6-18 years, with defined deletion status and echocardiograms (2003-2009) were identified from research databases. The diameter at the aortic annulus, sinus, and sinotubular junction was measured and analysed as Z-scores. Variables were examined in univariate and multivariate regression analysis.

RESULTS

Of 171 patients, 66% were male, 16% had 22q11.2 deletion, 40% had an aortic arch anomaly, and 11% had both a 22q11.2 deletion and aortic arch anomaly. Echocardiograms were performed at a mean age of 12 + 3 years. More patients with 22q11.2 deletion had Z-scores >3 at the sinus diameter (45% versus 35%, p = 0.02). In the multivariate analysis, the combination of 22q11.2 deletion and aortic arch anomalies was associated with both aortic annular dilation (p = 0.006) and aortic sinus dilation (p = 0.05). In the subset with pulmonary valve atresia, similar findings were observed at the aortic annulus (Z-score of 4.6 versus 2.2, p = 0.05) and the sinuses (Z-score of 4.4 versus 2.7, p = 0.06). Male sex (p < 0.03) and pulmonary atresia (p < 0.006) were additional risk factors for dilation at the annulus and sinuses.

CONCLUSIONS

Children with tetralogy of Fallot with 22q11.2 deletion and aortic arch anomalies have increased aortic annular and aortic sinus dilation. Further longitudinal study is needed to assess whether both features are associated with progressive aortic root dilation.

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.

Defining new guidelines for screening the 22q11.2 deletion based on a clinical and dysmorphologic evaluation of 194 individuals and review of the literature

The 22q11.2 deletion is the most frequent interstitial deletion in humans and presents a wide phenotypic spectrum, with over 180 clinical manifestations described. Distinct studies have detected frequencies of the deletion ranging from 0 % to 75 %, depending on the studied population and selection criteria adopted. Due to the lack of consensus in this matter, several studies have been conducted aiming to define which patients would be eligible for screening; however, the issue is still up for debate. In order to contribute to the delineation of possible clinical and dysmorphologic guidelines to optimize decision making in the clinical setting, 194 individuals with variable features of the 22q11.2 deletion syndromes (22q11.2DS) were evaluated. Group I, clinical suspicion of 22q11.2DS with palatal anomalies; Group II, clinical suspicion without palatal anomalies; Group III, cardiac malformations associated with the 22q11.2DS; and Group IV, juvenile-onset schizophrenia. Multiplex ligation-dependent probe amplification was used for screening the 22q11.2 deletion, which was detected in 45 patients (23.2 %), distributed as such: Group I, 35/101 (34.7 %); Group II, 4/18 (22.2 %); Group III, 6/52 (11.5 %); and Group IV, 0/23 (0 %). Clinical data were analyzed by frequency distribution and statistically. Based on the present results and on the review of the literature, we propose a set of guidelines for screening patients with distinct manifestations of the 22q11.2DS in order to maximize resources. In addition, we report the dysmorphic features which we found to be statistically correlated with the presence of the 22q11.2DS.

22q11.2 Deletion syndrome is associated with perioperative outcome in tetralogy of Fallot

OBJECTIVE

We sought to investigate the impact of 22q11.2 deletion on perioperative outcome in tetralogy of Fallot.

METHODS

We conducted a retrospective review of patients with tetralogy of Fallot who underwent complete surgical reconstruction at The Children's Hospital of Philadelphia between 1995 and 2006. Inclusion criteria included diagnosis of tetralogy of Fallot and known genotype. Fisher exact and Mann-Whitney tests were used for categoric and continuous variables, respectively. Regression analysis was used to determine whether deletion status predicts outcome.

RESULTS

We studied 208 subjects with tetralogy of Fallot, 164 (79%) without and 44 (20%) with 22q11.2 deletion syndrome. There were no differences in sex, race, gestational age, age at diagnosis, admission weight, and duration of mechanical ventilation. Presenting anatomy, survival, complications and reoperations were also comparable between patients with and without 22q11.2 deletion syndrome. Those with 22q11.2 deletion syndrome had more aortopulmonary shunts preceding complete surgical repair (21% vs 7%, P = .02). This association was present after adjustment for presenting anatomy (stenosis, atresia, or absence of pulmonary valve and common atrioventricular canal) and surgical era. In addition, those with 22q11.2 deletion syndrome had longer cardiopulmonary bypass time (84 vs 72 minutes, P = .02) and duration of intensive care (6 vs 4 days, P = .007).

CONCLUSIONS

Genotype affects early operative outcomes in tetralogy of Fallot resulting, in particular, in longer duration of intensive care. Future studies are required to determine factors contributing to such differences in this susceptible population.

Genome-wide association study identifies loci on 12q24 and 13q32 associated with tetralogy of Fallot

We conducted a genome-wide association study to search for risk alleles associated with Tetralogy of Fallot (TOF), using a northern European discovery set of 835 cases and 5159 controls. A region on chromosome 12q24 was associated (P = 1.4 × 10(-7)) and replicated convincingly (P = 3.9 × 10(-5)) in 798 cases and 2931 controls [per allele odds ratio (OR) = 1.27 in replication cohort, P = 7.7 × 10(-11) in combined populations]. Single nucleotide polymorphisms in the glypican 5 gene on chromosome 13q32 were also associated (P = 1.7 × 10(-7)) and replicated convincingly (P = 1.2 × 10(-5)) in 789 cases and 2927 controls (per allele OR = 1.31 in replication cohort, P = 3.03 × 10(-11) in combined populations). Four additional regions on chromosomes 10, 15 and 16 showed suggestive association accompanied by nominal replication. This study, the first genome-wide association study of a congenital heart malformation phenotype, provides evidence that common genetic variation influences the risk of TOF.

Aortopulmonary window in infants

One of the rarest congenital heart diseases that results from a defect between the main pulmonary artery and the proximal aorta is named aortopulmonary window (APW). Such abnormality could be isolated, but in fifty percent of patients may be associated with other cardiac abnormalities, including arch abnormalities, specifically coarctation of the aorta, interrupted aortic arch, tetralogy of fallot, and atrial septal defect (ASD). Surgical closure or catheter-delivered devices is recommended in all patients with APW and should be performed after diagnosis as soon as possible to prevent irreversible pulmonary vascular disease. In the current era, early mortality following repair of simple APW is low and depends on the presence of associated lesions, especially interrupted aortic arch. We report an 8-month-old boy with APW who was referred to our center by respiratory symptoms and heart murmurs.

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.

Can clinical assessment detect 22q11.2 deletions in patients with cardiac malformations? A review

INTRODUCTION

No consensus exists regarding the ability to detect the 22q11 deletion syndrome based on clinical assessment. Traditionally, diagnosis depends on clinical referral. Thus, individuals with typical manifestations are easily identified, but when manifestations are atypical or subclinical, diagnosis may be delayed or even missed. The aim of the present literature review was to evaluate the validity of clinical assessment as a method of predicting 22q11.2 deletions in individuals with congenital cardiac malformations.

METHODS

We identified 14 studies in which clinical assessment was blinded to the result from the genetic analysis.

RESULTS

Among 1458 patients, 159 (11% [9-13%]) carried the 22q11.2 deletion. The clinicians correctly identified 110 (69% [62-76%]) of them, whereas 49 (31% [24-38%]) would have remained undiagnosed if genetic screening had not been performed. Sensitivity, specificity, predictive value of positive and negative tests ranged from 0-100%, 43-100%, 7-100%, and 79-100%, respectively.

CONCLUSIONS

Clinical assessment identifies less than 3/4 patients with a 22q11.2 deletion, whereas more than 1/4 remain undiagnosed if genetic tests are not performed on a routine basis. In this review, we found that clinical assessment is not suited for detecting individuals to be tested for 22q11.2 deletions.

Multiplexed quantitative real-time PCR to detect 22q11.2 deletion in patients with congenital heart disease

22q11.2 Deletion syndrome (22q11.2 DS) [DiGeorge syndrome type 1 (DGS1)] occurs in ∼1:3,000 live births; 75% of children with DGS1 have severe congenital heart disease requiring early intervention. The gold standard for detection of DGS1 is fluorescence in situ hybridization (FISH) with a probe at the TUPLE1 gene. However, FISH is costly and is typically ordered in conjunction with a karyotype analysis that takes several days. Therefore, FISH is underutilized and the diagnosis of 22q11.2 DS is frequently delayed, often resulting in profound clinical consequences. Our goal was to determine whether multiplexed, quantitative real-time PCR (MQPCR) could be used to detect the haploinsufficiency characteristic of 22q11.2 DS. A retrospective blinded study was performed on 382 subjects who had undergone congenital heart surgery. MQPCR was performed with a probe localized to the TBX1 gene on human chromosome 22, a gene typically deleted in 22q11.2 DS. Cycle threshold (C(t)) was used to calculate the relative gene copy number (rGCN). Confirmation analysis was performed with the Affymetrix 6.0 Genome-Wide SNP Array. With MQPCR, 361 subjects were identified as nondeleted with an rGCN near 1.0 and 21 subjects were identified as deleted with an rGCN near 0.5, indicative of a hemizygous deletion. The sensitivity (21/21) and specificity (361/361) of MQPCR to detect 22q11.2 deletions was 100% at an rGCN value drawn at 0.7. One of 21 subjects with a prior clinical (not genetically confirmed) DGS1 diagnosis was found not to carry the deletion, while another subject, not previously identified as DGS1, was detected as deleted and subsequently confirmed via microarray. The MQPCR assay is a rapid, inexpensive, sensitive, and specific assay that can be used to screen for 22q11.2 deletion syndrome. The assay is readily adaptable to high throughput.

Cardiovascular anomalies associated with chromosome 22q11.2 deletion syndrome

Cardiovascular anomalies are present in 80% of neonates with 22q11.2 deletion syndrome. Three genes in chromosome 22q11.2 (TBX1, CRKL, and ERK2) have been identified whose haploinsufficiency causes dysfunction of the neural crest cell and anterior heart field and anomalies of 22q11.2 deletion syndrome. The most common diseases are conotruncal anomalies, which include tetralogy of Fallot (TF), TF with pulmonary atresia, truncus arteriosus, and interrupted aortic arch. A high prevalence of the deletion is noted in patients with TF with absent pulmonary valve, TF associated with pulmonary atresia and major aortopulmonary collateral arteries, truncus arteriosus, and type B interruption of aortic arch. Right aortic arch, aberrant subclavian artery, cervical origin of the subclavian artery, crossing pulmonary arteries, and major aortopulmonary collateral arteries are frequently associated with cardiovascular anomalies associated with 22q11.2 deletion syndrome. Virtually every type of congenital heart defect has been described early in the context of a 22q11.2 deletion. In conclusion, conotruncal anomaly associated with aortic arch and ductus arteriosus anomalies should increase the suspicion of 22q11.2 deletion.

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.

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.

Early repair of hemitruncus: excellent early and late outcomes

OBJECTIVE

Anomalous origin of 1 of the branch pulmonary arteries from the aorta with 2 normal semilunar valves (hemitruncus) is a rare entity. There have been several small case series reported. We report here our single-institution surgical experience with hemitruncus from 1982 to 2006.

METHODS

A retrospective case review of all cases of conotruncal anomalies at Children's Hospital Boston revealed 16 patients with hemitruncus. Ten patients had surgery in the neonatal period (<30 days), 4 at 1 to 6 months, 1 at 8 months, and 1 at 2 years. Diagnosis of hemitruncus was the indication for operation in all but 1. Fourteen of the 16 had anomalous right pulmonary artery from aorta, and 2 had left pulmonary artery from aorta. Common associated anomalies included patent foramen ovale in 14, patent ductus arteriosus in 11, and ventricular septal defect in 4. All patients had elevated right ventricular pressures with systemic pressures in 5 and suprasystemic pressures in 9.

RESULTS

There was 1 operative death in this series in an infant who died from sepsis following ligation of a tracheoesophageal fistula. One patient required reoperation for supravalvular aortic stenosis and right pulmonary artery stenosis 1 year postoperatively. Three patients required 4 catheter-based interventions postoperatively. At 20 years, survival by Kaplan-Meier was 93%; freedom from reoperation, 93%; and freedom from catheter reintervention, 79%.

CONCLUSIONS

Early repair of hemitruncus results in excellent hemodynamic and anatomic results. Survival is excellent, with a low incidence of reoperation or reintervention.

Deletion 22q11 and isolated congenital heart disease

The real prevalence of deletion 22 (del22) in isolated congenital heart defects is still disputed. The experience of our group suggests that patients with CHD and del22 have classic or subtle extracardiac features, so that an accurate clinical evaluation of patients with CHD is needed before stating that the defect is isolated.

Surgical repair of aortopulmonary window: thirty-seven years of experience

An aortopulmonary window (APW) is a communication between the ascending aorta and the pulmonary trunk in the presence of two separate semilunar valves. In order to increase our understanding about the surgical management of this rare lesion and its long-term results, we describe our experience over a 37-year period. Between 1968 and 2005, 18 patients were diagnosed with APW. Seventeen underwent surgical correction. Age at operation ranged from 22 days to 22 years (median, 0.20 years). Follow-up ranged from 2 weeks to 28.6 years (median, 11.0 years). Surgical closure was achieved using a single patch in 7 patients (41.2%) double patch in 4 (23.5%), primary closure in 3 (17.6%), clip in 2 (11.8%), and ligation in 1 (5.9%). Complex APW was present in 8 patients (44.4%). One patient was treated nonsurgically. There were no early or late deaths after surgery. Both primary closure and patch closure gave excellent long-term results. Sporadic postoperative complications were only associated with complex lesions. One patient who was treated conservatively died (of pulmonary hypertension) 21 years after diagnosis. Repair of APW is ideally performed in the first months of life, before irreversible PHT has developed. Various surgical repair techniques in this series of patients gave excellent short-term and long-term results, without significant hemodynamic sequelae.

Chromosome 22q11 deletions in patients with conotruncal heart defects

We performed this study to determine the frequency of 22q11 deletions and associated phenotypic features and abnormalities in conotruncal heart defects. Sixty-one patients with conotruncal heart defects, including tetralogy of Fallot (TOF; n = 32), pulmonary atresia/ventricular septal defect (PAVSD; n = 12), double-outlet right ventricle (DORV; n = 5), transposition of the great arteries (TGA; n = 4 ), truncus arteriosus (TA; n = 4), subpulmonary ventricular septal defect (SPVSD; n = 3), and interrupted aortic arch (IAA; n = 1), were enrolled in this study and screened for 22q11 deletions by the fluorescence in situ hybridization technique. Phenotypic features and associated abnormalities, including submucosal cleft palate, abnormal facies, square nose, nasal voice, abnormal ears, long and slender fingers, delayed development, mental retardation, delayed growth, short stature, and hypocalcemia, were examined in these patients. Nine of 61 patients (14.8%) had 22q11 deletions, including 100% of IAA, 50% of TA, 33.3% of SPVSD, 33.3% of PAVSD, and 3.1% of TOF. Deletions were not detected in DORV and TGA. In all patients with 22q11 deletions, > or =1 phenotypic features or associated abnormalities were observed. A subgroup of patients with IAA, TA, SPVSD, and PAVSD associated with phenotypic features or abnormalities warrants evaluation for the presence of 22q11 deletions.

New trends in chromosomal investigation in children with cardiovascular malformations

We investigated a group of 376 children, seen over a period of 7 years with different types of congenital cardiovascular defects, to assess the presence of chromosomal aberrations. The diagnostic approach, achieved in 3 consecutive steps, revealed conventional chromosomal aberrations in 30 of the patients (8%) excluding trisomies 13, 18, 21. Fluorescence in situ hybridisation for microdeletions showed 51 microdeletions (15%), with 43 patients having deletions of 22q11.2, 7 patients with deletion of 7q11.23, and 1 patient with deletion of 4p16.3. In 23 patients with additional clinical abnormalities, we carried out a subtelomeric screening. This revealed, in two cases (9%), different subtelomeric aberrations, namely deletions of 1p and of 1q. Thus, subtelomeric screening proved to be a very valuable as a new diagnostic approach. Our approach to genetic investigation in three phases makes it possible to detect a high rate of pathologic karyotypes in patients with congenital cardiovascular malformations, thus guaranteeing more effective genetic counselling of the families, and a more precise prognosis for the patient.

Missense mutations and gene interruption in PROSIT240, a novel TRAP240-like gene, in patients with congenital heart defect (transposition of the great arteries)

BACKGROUND

Congenital heart disease represents the most common severe birth defect, affecting 0.7% to 1% of all neonates, among whom 5% to 7% display transposition of the great arteries (TGA). TGA represents a septation defect of the common outflow tract of the heart, manifesting around the fifth week during embryonic development. Despite its high prevalence, very little is known about the pathogenesis of this disease.

METHODS AND RESULTS

Using a positional cloning approach, we isolated a novel gene, PROSIT240 (also termed THRAP2), that is interrupted in a patient with a chromosomal translocation and who displays TGA and mental retardation. High expression of PROSIT240 within the heart (aorta) and brain (cerebellum) was well correlated with the malformations observed in the patient and prompted further analyses. PROSIT240 shows significant homology to the nuclear receptor coactivator TRAP240, suggesting it to be a new component of the thyroid hormone receptor-associated protein (TRAP) complex. Interestingly, several TRAP components have been previously shown to be important in early embryonic development in various organisms, making PROSIT240 an excellent candidate gene to be correlated to the patient's phenotype. Subsequent mutational screening of 97 patients with isolated dextro-looped TGA revealed 3 missense mutations in PROSIT240, which were not detected in 400 control chromosomes.

CONCLUSIONS

Together, these genetic data suggest that PROSIT240 is involved in early heart and brain development.

Search for deletion 22q11.2 in interphase nuclei of buccal mucosa of patients ascertained by isolated cleft palate: a new diagnostic approach

A new approach for the detection of chromosome deletion 22q11.2 in interphase nuclei from buccal mucosa cells obtained by a non-invasive procedure is described. FISH analysis has been performed on samples from a group of 101 patients that presented consecutively for speech therapy and/or surgical correction of cleft palate. A normal result has been obtained in 98 patients; a deletion 22q11.2 was present in three patients (2.8%) with cleft palate.

CFC1 mutations in patients with transposition of the great arteries and double-outlet right ventricle

Recent investigations identified heterozygous CFC1 mutations in subjects with heterotaxy syndrome, all of whom had congenital cardiac malformations, including malposition of the great arteries. We hypothesized that a subset of patients with similar types of congenital heart disease---namely, transposition of the great arteries and double-outlet right ventricle, in the absence of laterality defects---would also have CFC1 mutations. Our analysis of the CFC1 gene in patients with these cardiac disorders identified two disease-related mutations in 86 patients. The present study identifies the first autosomal single-gene defect for these cardiac malformations and indicates that some cases of transposition of the great arteries and double-outlet right ventricle can share a common genetic etiology with heterotaxy syndrome. In addition, these results demonstrate that the molecular pathway involving CFC1 plays a critical role in normal and abnormal cardiovascular development.

Can we predict 22q11 status of fetuses with tetralogy of Fallot?

OBJECTIVE

To determine if chromosome 22q11 deletion status can be predicted in fetuses with tetralogy of Fallot as regards additional phenotypic anomalies.

METHODS

One hundred and fifty-one consecutive fetuses with tetralogy of Fallot without or with pulmonary atresia were screened for 22q11 deletion. Additional echographic features [increased nuchal translucency (NT), intrauterine growth retardation (IUGR), polyhydramnios, extracardiac malformations, pulmonary arteries abnormalities] were noted.

RESULTS

Twenty-five fetuses had a 22q11 deletion (16.6%). Increased NT, polyhydramnios and IUGR were more frequent in fetuses with 22q11 deletion as well as pulmonary arterial abnormalities. When these different features were present in the same fetus with tetralogy of Fallot, 22q11 deletion can be predicted with a sensitivity of 88%.

CONCLUSION

Simple echographic features can help to predict 22q11 status in fetuses with tetralogy of Fallot. This may improve the efficiency of prenatal screening for this defect.

Molecular characterization of chromosome 22 deletions by short tandem repeat polymorphism (STRP) in patients with conotruncal heart defects

The haploinsufficiency of chromosome 22q11.2 can cause both DiGeorge and velocardiofacial syndromes, both of which are characterized by conotruncal heart defects as well as a wide range of other extracardiac anomalies. Several studies have demonstrated that approximately 10-20% of patients with conotruncal heart defects have a 22q11.2 deletion. In clinical laboratories, the deletion is usually detected by fluorescent in situ hybridization (FISH). We set up a polymerase chain reaction-based non-radioactive method for molecular analysis of the 22q11.2 region in conotruncal cardiac patients with conotruncal defects. Sixty-four children with conotruncal defects and their parents were genotyped by polymerase chain reaction, using fifteen polymorphic markers. We identified nine deletions (confirmed by FISH): eight were "de novo" and one familial, maternally inherited. Six deletions were of paternal and three of maternal origin. There were seven deletions of 3 Mb and the other two were of 1.5 Mb. This method is a cost-effective means of characterizing the 22q11.2 region and it can be applied for a rapid screening of 22q11.2 deletion in patients at risk. In agreement with previously published data, we found no correlation between the sizes and the parental origin of deletions and cardiac or extra-cardiac phenotypes.

NKX2.5 mutations in patients with tetralogy of fallot

BACKGROUND

Recent reports have implicated mutations in the transcription factor NKX2.5 as a cause of tetralogy of Fallot (TOF). To estimate the frequency of NKX2.5 mutations in TOF patients and to further investigate the genotype-phenotype correlation of NKX2.5 mutations, we genotyped 114 TOF patients.

METHODS AND RESULTS

Patients were recruited prospectively (November 1992 through June 1999) and tested for a 22q11 deletion; those with 22q11 deletion or recognized chromosomal alteration were excluded from the present study. Patients were screened for NKX2.5 alterations by conformation-sensitive gel electrophoresis and sequencing of fragments with aberrant mobility. Four heterozygous mutations were identified in 6 unrelated patients with cases of TOF, including 3 with pulmonary atresia and 5 with right aortic arch; none had ECG evidence of PR interval prolongation. Three of 4 mutations (Glu21Gln, Arg216Cys, and Ala219Val) altered highly conserved amino acids, of which 2 mapped in the conserved NK2 domain. The fourth mutation (Arg25Cys) was identified in 3 unrelated probands in the present study and has been previously reported. No homeodomain mutations were identified.

CONCLUSIONS

NKX2.5 mutations are the first gene defects identified in nonsyndromic TOF patients. NKX2.5 mutation is present in >/=4% of TOF patients. Mutations identified in the present study mapped outside of the homeodomain, were not associated with atrioventricular conduction disturbances, and were not fully penetrant, in contrast to mutations previously reported that impair homeodomain function.

The epidemiology and genetics of congenital heart disease

The studies summarized demonstrate that CHD is a common, major malformation. The genetic cause of each specific lesion is heterogeneous. In addition, different types of CHD can result from the same chromosomal alteration or from mutations in the same gene. Although one might predict that genotype influences clinical outcome, further studies are required. At this time, routine clinical diagnostic tests to identify the specific genetic cause are available in only a few cases, namely, those with abnormal karyotypes or those with a 22q11 deletion. In those cases with single-gene defects, genetic testing is not clinically available at this time and most likely will not become available until we can predict the significance of each mutation and until technologic advances are made that allow for large-scale, accurate screening. In the meantime, continued research on the genetic cause of CHD promises to augment our understanding of the mechanisms underlying the normal and abnormal development of the cardiac structures. These investigations also promise to augment our ability to counsel families on the recurrence risk with greater accuracy and, in the future, will allow the physician to modify his or her clinical management based on genetic cause. Finally, identifying the cause and understanding the disease mechanism allows for early intervention that may modify the degree of cardiac maldevelopment or avoid cardiac malformation altogether.

Prenatal diagnosis of the 22q11.2 deletion syndrome

The development of fluorescence in situ hybridization (FISH)- and polymerase chain reaction (PCR)-based assays for the detection of deletions of chromosome 22q11.2 has enabled the medical community to offer couples at risk prenatal diagnostic testing. Current indications for testing include a previous child with a 22q11.2 deletion or DiGeorge/velocardiofacial syndrome, an affected parent with a 22q11.2 deletion, and in utero detection of a conotruncal cardiac defect. Antenatal knowledge of the deletion status provides couples and clinicians with an accurate diagnosis, prognostic information, and recurrence risk, which may assist couples with their reproductive decisions. However, there are limitations to prenatal testing, which should be reviewed prior to testing.

Anatomic patterns of conotruncal defects associated with deletion 22q11

PURPOSE

Patients with cardiovascular malformations (CVMs) and deletion 22q11 from our series were studied in order to (1) analyze the association with dysmorphic features and noncardiac anomalies, (2) identify specific cardiac patterns and the distinctive association with additional CVMs.

METHODS

From 1993 to 2000, 931 patients with CVM (95 with a clinical diagnosis of DiGeorge/velocardiofacial syndrome (DG/VCFS), 208 with different genetic syndromes, 628 without dysmorphic features) underwent accurate cardiac assessment, clinical and phenotypical examination, and screening for deletion 22q11 by fluorescence in situ hybridization (FISH).

RESULTS

Deletion 22q11 was detected in 88 of the total patients, and in 87 of the 95 patients with a clinical diagnosis of DG/VCFS. Only one patient among the 628 without dysmorphic features had deletion 22q11. Conotruncal heart defects were the most common CVMs, often presenting in association with additional anomalies in four areas of the cardiovascular system: (1) the aortic arch can be right sided, cervical, double, and the subclavian artery can be aberrant, (2) the pulmonary arteries can present discontinuity, diffuse hypoplasia, discrete stenosis, defect of arborization and major aortopulmonary collateral arteries (MAPCA), (3) the infundibular septum can be malaligned, hypoplastic, or absent, (4) the semilunar valves can be bicuspid, severely dysplastic, insufficient, or stenotic.

CONCLUSION

In subjects with deletion 22q11 CVM is virtually always associated with one or more noncardiac anomalies. Deletion 22q11 is exceptionally rare in children with nonsyndromic CVMs. Specific patterns of CVMs are observed in patients with deletion 22q11, including (1) anomalies of the aortic arch, (2) anomalies of the pulmonary arteries and of the pulmonary blood supply, (3) defects of the infundibular septum, (4) malformations of the semilunar valves. These additional CVMs may influence the surgical treatment of these patients.

Familial absent pulmonary valve syndrome without deletions of chromosome 22q11

Deletions of chromosome 22q11 are common in patients with tetralogy of Fallot, and in those with absent pulmonary valve syndrome. In this report, we describe a pair of siblings with absent pulmonary valve syndrome, neither of whom had deletions of chromosome 22q11. The finding of familial absent pulmonary valve syndrome without deletion of 22q11 in our patients suggests an alternative genetic basis for this rare condition.

Anatomical reconstruction of aorta and pulmonary trunk in patients with an aortopulmonary window

We report a modified technique for repair of aortopulmonary window in which a native pulmonary artery flap is created and the aortopulmonary window is completely divided. The pulmonary artery flap is used to reconstruct the ascending aorta, and the defect in the pulmonary trunk is closed with an autologous pericardial patch. This repair avoids the use of a fabric patch with its inherent disadvantages and allows anatomical reconstruction of both the ascending aorta and the pulmonary trunk with low risk of early or late distortion of the aortic and pulmonary root structures.

22q11 deletion syndrome: a genetic subtype of schizophrenia

Schizophrenia is likely to be caused by several susceptibility genes and may have environmental factors that interact with susceptibility genes and/or nongenetic causes. Recent evidence supports the likelihood that 22q11 Deletion Syndrome (22qDS) represents an identifiable genetic subtype of schizophrenia. 22qDS is an under-recognized genetic syndrome associated with microdeletions on chromosome 22 and a variable expression that often includes mild congenital dysmorphic features, hypernasal speech, and learning difficulties. Initial evidence indicates that a minority of patients with schizophrenia (approximately 2%) may have 22qDS and that prevalence may be somewhat higher in subpopulations with developmental delay. This paper proposes clinical criteria (including facial features, learning disabilities, hypernasal speech, congenital heart defects and other congenital anomalies) to aid in identifying patients with schizophrenia who may have this subtype and outlines features that may increase the index of suspicion for this syndrome. Although no specific causal gene or genes have yet been identified in the deletion region, 22qDS may represent a more homogeneous subtype of schizophrenia. This subtype may serve as a model for neurodevelopmental origins of schizophrenia that could aid in delineating etiologic and pathogenetic mechanisms.

Advances in the molecular genetics of congenital structural heart disease

Molecular genetic analyses have generated significant advances in our understanding of congenital heart disease. Techniques of genetic mapping with polymorphic microsatellites and fluorescence in situ hybridization (FISH) have provided informative tools for localization and identification of disease genes. Some cardiovascular diseases have proven to result from single gene defects. Others relate to more complex etiologies involving several genes and their interactions. Elucidation of the molecular genetic etiologies of congenital heart disease prompts consideration of DNA testing for cardiac disorders. Future integration of these diagnostic modalities with improved treatments may ultimately decrease morbidity and mortality from congenital heart diseases.

PCR assay for screening patients at risk for 22q11.2 deletion

Deletions of 22q11.2 have been detected in the majority of patients with DiGeorge, velocardiofacial, and conotruncal anomaly face syndromes by either cytogenetic analysis, fluorescence in situ hybridization (FISH), or Southern blot hybridization. However, these techniques may not be the most efficient or cost-effective means of screening large numbers of "at-risk" patients. Therefore, we developed a PCR assay to assess a patient's likelihood of having a 22q11.2 deletion based on homozygosity at consecutive markers in the DiGeorge chromosomal region. The sensitivity and specificity of PCR screening were evaluated in a cohort of cardiac patients. We conclude that a PCR-based assay is a reliable and efficient means of identifying which patients are at greatest risk for a 22q11.2 deletion and should have FISH studies to confirm their deletion status.

Bisdiamine inhibits extracellular matrix formation and cell proliferation of atrioventricular mesenchyme from developing chick heart valves

Abnormalities of the cushion tissues lead to atrioventricular septal defects (AVSD) and truncus arteriosus (TA). Bisdiamine exposure in the embryo frequently causes AVSD and TA in the newborn chick, mouse, or rat. We studied the effects of bisdiamine on mesenchymal cells grown in aggregate culture isolated from the developing atrioventricular valves of the stage-36 chick embryo. Fibronectin extracellular matrix formation and cell proliferation in the aggregates were assessed in various media. Chick serum stimulated the cells to produce an extracellular matrix and to divide, and the inclusion of bisdiamine inhibited both responses. If we isolated an extracellular matrix from a monolayer of mesenchymal cells and added the sonicated matrix to the medium containing serum and bisdiamine, the matrix incorporated into the aggregates and the cells entered the mitotic cycle. Our previous work established that cells need to attach to an intact extracellular matrix to begin cell division. Thus, we suggest that bisdiamine inhibits the normal formation of the extracellular matrix, leading to reduced cell proliferation, but it does not affect matrix-cell interaction. The lack of cushion growth in situ may be the cause of AVSD or TA.

Persistent truncus arteriosus in monozygotic twins: case report and literature review

We report on a pair of monozygotic twins with persistent truncus arteriosus. They had no evident clinical signs of DiGeorge syndrome. Pathologic examination of the placenta and DNA analysis in chromosomes 7, 8, and 15 was consistent with monozygosity. Fluorescence in situ hybridization test was negative for chromosome 22q11 microdeletion. Family history revealed a female cousin with tetralogy of Fallot. The isolated presence of this conotruncal abnormality in monozygotic twins is extremely rare. The genetic considerations are discussed.

22q11 deletions in patients with conotruncal heart defects

OBJECTIVE

To ascertain the frequency of 22q11 deletions in a representative population of conotruncal heart defects (CTD) and determine which children are at risk of having a deletion.

METHODOLOGY

A clinical and laboratory evaluation of 90 children with CTD, including isolated and syndromic cases.

RESULTS

Fifteen children (17%) were shown to have 22q11 deletions by fluorescence in situ hybridization (FISH) studies with the Oncor probe N25. Varying degrees of developmental delay/learning disabilities and facial dysmorphism were common in these children. None of the isolated cases without dysmorphism had a deletion.

CONCLUSION

22q11 deletions are a significant cause of a specific form of congenital heart disease, CTD. It is important to have a high index of suspicion of the 22q11 deletion disorders in children with CTD and other extracardiac manifestations so that the diagnosis can be made early and appropriate interventions implemented.

A population study of chromosome 22q11 deletions in infancy

AIMS

To determine the prevalence of submicroscopic deletions within chromosome band 22q11 in infants with significant heart disease and compare this with the prevalence of other chromosomal abnormalities causing significant heart disease. To determine a minimum prevalence of deletions within chromosome band 22q11 in infants in the general population.

METHODS

Chromosome analysis was performed on samples from infants born in the former UK Northern Health Region in 1994 and 1995 who either had significant heart disease or who were suspected to have a chromosome band 22q11 deletion following referral to the Northern Genetics Service. Significant heart disease was defined as major structural malformation or cases where invasive investigation or intervention was required in infancy.

RESULTS

Chromosome band 22q11 deletions were identified in nine infants in a population of 69,129 livebirths, giving a minimum prevalence of 13 per 100,000 (95% confidence interval 4.5 to 21.5). Six cases had significant heart disease, one of whom died before diagnosis. In the same population there were 53 cases of trisomy 21, 15 of whom had significant heart disease.

CONCLUSION

The most common chromosomal cause of significant congenital heart disease remains trisomy 21, while the second most common chromosomal cause is deletion in chromosome band 22q11.