The 22q11.2 deletion syndrome has an estimated prevalence of 1 in 4–6,000 livebirths. The phenotype varies widely; the most common features include: facial dysmorphia, hypocalcemia, palate and speech ...disorders, feeding and gastrointestinal disorders, immunodeficiency, recurrent infections, neurodevelopmental and psychiatric disorders, and congenital heart disease. Approximately 60–80% of patients have a cardiac malformation most commonly including a subset of conotruncal defects (tetralogy of Fallot, truncus arteriosus, interrupted aortic arch type B), conoventricular and/or atrial septal defects, and aortic arch anomalies. Cardiac patients with a 22q11.2 deletion do not generally experience higher mortality upon surgical intervention but suffer more peri‐operative complications than their non‐syndromic counterparts. New guidelines suggest screening for a 22q11.2 deletion in the patient with tetralogy of Fallot, truncus arteriosus, interrupted aortic arch type B, conoventricular septal defects as well as those with an isolated aortic arch anomaly. Early identification of a 22q11.2 deletion in the neonate or infant when other syndromic features may not be apparent allows for timely parental screening for reproductive counseling and anticipatory evaluation of cardiac and noncardiac features. Screening the at‐risk child or adult allows for important age‐specific clinical, neurodevelopmental, psychiatric, and reproductive issues to be addressed.
Dysfunction of motile monocilia, altering the leftward flow at the embryonic node essential for determination of left-right body asymmetry, is a major cause of laterality defects. Laterality defects ...are also often associated with reduced mucociliary clearance caused by defective multiple motile cilia of the airway and are responsible for destructive airway disease. Outer dynein arms (ODAs) are essential for ciliary beat generation, and human respiratory cilia contain different ODA heavy chains (HCs): the panaxonemally distributed γ-HC DNAH5, proximally located β-HC DNAH11 (defining ODA type 1), and the distally localized β-HC DNAH9 (defining ODA type 2). Here we report loss-of-function mutations in DNAH9 in five independent families causing situs abnormalities associated with subtle respiratory ciliary dysfunction. Consistent with the observed subtle respiratory phenotype, high-speed video microscopy demonstrates distally impaired ciliary bending in DNAH9 mutant respiratory cilia. DNAH9-deficient cilia also lack other ODA components such as DNAH5, DNAI1, and DNAI2 from the distal axonemal compartment, demonstrating an essential role of DNAH9 for distal axonemal assembly of ODAs type 2. Yeast two-hybrid and co-immunoprecipitation analyses indicate interaction of DNAH9 with the ODA components DNAH5 and DNAI2 as well as the ODA-docking complex component CCDC114. We further show that during ciliogenesis of respiratory cilia, first proximally located DNAH11 and then distally located DNAH9 is assembled in the axoneme. We propose that the β-HC paralogs DNAH9 and DNAH11 achieved specific functional roles for the distinct axonemal compartments during evolution with human DNAH9 function matching that of ancient β-HCs such as that of the unicellular Chlamydomonas reinhardtii.
RATIONALE:Congenital heart disease (CHD) is among the most common birth defects. Most cases are of unknown pathogenesis.
OBJECTIVE:To determine the contribution of de novo copy number variants (CNVs) ...in the pathogenesis of sporadic CHD.
METHODS AND RESULTS:We studied 538 CHD trios using genome-wide dense single nucleotide polymorphism arrays and whole exome sequencing. Results were experimentally validated using digital droplet polymerase chain reaction. We compared validated CNVs in CHD cases with CNVs in 1301 healthy control trios. The 2 complementary high-resolution technologies identified 63 validated de novo CNVs in 51 CHD cases. A significant increase in CNV burden was observed when comparing CHD trios with healthy trios, using either single nucleotide polymorphism array (P=7×10; odds ratio, 4.6) or whole exome sequencing data (P=6×10; odds ratio, 3.5) and remained after removing 16% of de novo CNV loci previously reported as pathogenic (P=0.02; odds ratio, 2.7). We observed recurrent de novo CNVs on 15q11.2 encompassing CYFIP1, NIPA1, and NIPA2 and single de novo CNVs encompassing DUSP1, JUN, JUP, MED15, MED9, PTPRE SREBF1, TOP2A, and ZEB2, genes that interact with established CHD proteins NKX2-5 and GATA4. Integrating de novo variants in whole exome sequencing and CNV data suggests that ETS1 is the pathogenic gene altered by 11q24.2-q25 deletions in Jacobsen syndrome and that CTBP2 is the pathogenic gene in 10q subtelomeric deletions.
CONCLUSIONS:We demonstrate a significantly increased frequency of rare de novo CNVs in CHD patients compared with healthy controls and suggest several novel genetic loci for CHD.
We present CANOES, an algorithm for the detection of rare copy number variants from exome sequencing data. CANOES models read counts using a negative binomial distribution and estimates variance of ...the read counts using a regression-based approach based on selected reference samples in a given dataset. We test CANOES on a family-based exome sequencing dataset, and show that its sensitivity and specificity is comparable to that of XHMM. Moreover, the method is complementary to Gaussian approximation-based methods (e.g. XHMM or CoNIFER). When CANOES is used in combination with these methods, it will be possible to produce high accuracy calls, as demonstrated by a much reduced and more realistic de novo rate in results from trio data.
Assessing right ventricular (RV) performance is essential for patients with tetralogy of Fallot (TOF). The aim of this study was to investigate the reliability and validity of tricuspid annular plane ...systolic excursion (TAPSE) against cardiac magnetic resonance imaging measures and cardiopulmonary exercise testing.
A retrospective study was performed in 125 outpatients with repaired TOF with available protocol-driven echocardiography, cardiac magnetic resonance imaging, and exercise stress testing obtained as part of a cross-sectional study. TAPSE was measured on the two-dimensional apical four-chamber view on echocardiography by two readers. Multivariate linear regression was used to examine the association between TAPSE and measures of RV function and exercise capacity.
The mean age was 12.6 ± 3.3 years, 41 patients (33%) were female, and 104 (83%) were white. TAPSE averaged 1.6 ± 0.37 cm, with an interreader intraclass correlation coefficient of 0.78 (n = 18). TAPSE was significantly associated with cardiac magnetic resonance-based RV stroke volume after adjustment for gender and body surface area (β = 13.8; 95% confidence interval, 2.25-25.30; P = .02). TAPSE was not associated with cardiac magnetic resonance-based RV ejection fraction (P = .77). On exercise testing, TAPSE was not associated with peak oxygen consumption, percentage of predicted oxygen consumption, oxygen pulse, or the ventilatory equivalent for carbon dioxide in patients with maximal exercise stress testing (n = 73 58%).
TAPSE is reproducibly measured by echocardiography in patients with TOF. It is not associated with RV ejection fraction or exercise performance, and its association with RV stroke volume may be confounded by body size. On the basis of these results, TAPSE is not representative of global RV performance in patients with TOF.
The Pediatric Cardiac Genomics Consortium (PCGC) designed the Congenital Heart Disease Genetic Network Study to provide phenotype and genotype data for a large congenital heart defects (CHDs) cohort. ...This article describes the PCGC cohort, overall and by major types of CHDs (e.g., conotruncal defects) and subtypes of conotrucal heart defects (e.g., tetralogy of Fallot) and left ventricular outflow tract obstructions (e.g., hypoplastic left heart syndrome). Cases with CHDs were recruited through ten sites, 2010-2014. Information on cases (N = 9,727) and their parents was collected through interviews and medical record abstraction. Four case characteristics, eleven parental characteristics, and thirteen parent-reported neurodevelopment outcomes were summarized using counts and frequencies and compared across CHD types and subtypes. Eleven percent of cases had a genetic diagnosis. Among cases without a genetic diagnosis, the majority had conotruncal heart defects (40%) or left ventricular outflow tract obstruction (21%). Across CHD types, there were significant differences (p<0.05) in the distribution of all four case characteristics (e.g., sex), four parental characteristics (e.g., maternal pregestational diabetes), and five neurodevelopmental outcomes (e.g., learning disabilities). Several characteristics (e.g., sex) were also significantly different across CHD subtypes. The PCGC cohort is one of the largest CHD cohorts available for the study of genetic determinants of risk and outcomes. The majority of cases do not have a genetic diagnosis. This description of the PCGC cohort, including differences across CHD types and subtypes, provides a reference work for investigators who are interested in collaborating with or using publically available resources from the PCGC.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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.
The genetic architecture of sporadic congenital heart disease (CHD) is characterized by enrichment in damaging de novo variants in chromatin-modifying genes. To test the hypothesis that gene pathways ...contributing to de novo forms of CHD are distinct from those for recessive forms, we analyze 2391 whole-exome trios from the Pediatric Cardiac Genomics Consortium. We deploy a permutation-based gene-burden analysis to identify damaging recessive and compound heterozygous genotypes and disease genes, controlling for confounding effects, such as background mutation rate and ancestry. Cilia-related genes are significantly enriched for damaging rare recessive genotypes, but comparatively depleted for de novo variants. The opposite trend is observed for chromatin-modifying genes. Other cardiac developmental gene classes have less stratification by mode of inheritance than cilia and chromatin-modifying gene classes. Our analyses reveal dominant and recessive CHD are associated with distinct gene functions, with cilia-related genes providing a reservoir of rare segregating variation leading to CHD.
Heterotaxy, a birth defect involving left-right patterning defects, and primary ciliary dyskinesia (PCD), a sinopulmonary disease with dyskinetic/immotile cilia in the airway are seemingly disparate ...diseases. However, they have an overlapping genetic etiology involving mutations in cilia genes, a reflection of the common requirement for motile cilia in left-right patterning and airway clearance. While PCD is a monogenic recessive disorder, heterotaxy has a more complex, largely non-monogenic etiology. In this study, we show mutations in the novel dynein gene DNAH6 can cause heterotaxy and ciliary dysfunction similar to PCD. We provide the first evidence that trans-heterozygous interactions between DNAH6 and other PCD genes potentially can cause heterotaxy. DNAH6 was initially identified as a candidate heterotaxy/PCD gene by filtering exome-sequencing data from 25 heterotaxy patients stratified by whether they have airway motile cilia defects. dnah6 morpholino knockdown in zebrafish disrupted motile cilia in Kupffer's vesicle required for left-right patterning and caused heterotaxy with abnormal cardiac/gut looping. Similarly DNAH6 shRNA knockdown disrupted motile cilia in human and mouse respiratory epithelia. Notably a heterotaxy patient harboring heterozygous DNAH6 mutation was identified to also carry a rare heterozygous PCD-causing DNAI1 mutation, suggesting a DNAH6/DNAI1 trans-heterozygous interaction. Furthermore, sequencing of 149 additional heterotaxy patients showed 5 of 6 patients with heterozygous DNAH6 mutations also had heterozygous mutations in DNAH5 or other PCD genes. We functionally assayed for DNAH6/DNAH5 and DNAH6/DNAI1 trans-heterozygous interactions using subthreshold double-morpholino knockdown in zebrafish and showed this caused heterotaxy. Similarly, subthreshold siRNA knockdown of Dnah6 in heterozygous Dnah5 or Dnai1 mutant mouse respiratory epithelia disrupted motile cilia function. Together, these findings support an oligogenic disease model with broad relevance for further interrogating the genetic etiology of human ciliopathies.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Congenital heart diseases (CHDs) and cardiovascular abnormalities are one of the pillars of clinical diagnosis of 22q11.2 deletion syndrome (22q11.2DS) and still represent the main cause of mortality ...in the affected children. In the past 30 years, much progress has been made in describing the anatomical patterns of CHD, in improving their diagnosis, medical treatment, and surgical procedures for these conditions, as well as in understanding the underlying genetic and developmental mechanisms. However, further studies are still needed to better determine the true prevalence of CHDs in 22q11.2DS, including data from prenatal studies and on the adult population, to further clarify the genetic mechanisms behind the high variability of phenotypic expression of 22q11.2DS, and to fully understand the mechanism responsible for the increased postoperative morbidity and for the premature death of these patients. Moreover, the increased life expectancy of persons with 22q11.2DS allowed the expansion of the adult population that poses new challenges for clinicians such as acquired cardiovascular problems and complexity related to multisystemic comorbidity. In this review, we provide a comprehensive review of the existing literature about 22q11.2DS in order to summarize the knowledge gained in the past years of clinical experience and research, as well as to identify the remaining gaps in comprehension of this syndrome and the possible future research directions.
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