ABSTRACT
Background: Despite monogenic and polygenic contributions to cardiovascular disease (CVD), genetic testing is not widely adopted, and current tests are limited by the breadth of surveyed conditions and interpretation burden. Methods: We developed a comprehensive clinical genome CVD test with semi-automated interpretation. Monogenic conditions and risk alleles were selected based on the strength of disease association and evidence for increased disease risk, respectively. Non-CVD secondary findings genes, pharmacogenomic (PGx) variants and CVD polygenic risk scores (PRS) were assessed for inclusion. Test performance was modeled using 2,594 genomes from the 1000 Genomes Project, and further investigated in 20 previously tested individuals. Results: The CVD genome test is composed of a panel of 215 CVD gene-disease pairs, 35 non-CVD secondary findings genes, 4 risk alleles or genotypes, 10 PGx genes and a PRS for coronary artery disease. Modeling of test performance using samples from the 1000 Genomes Project revealed ~6% of individuals with a monogenic finding in a CVD-associated gene, 6% with a risk allele finding, ~1% with a non-CVD secondary finding, and 93% with CVD-associated PGx variants. Assessment of blinded clinical samples showed complete concordance with prior testing. An average of 4 variants were reviewed per case, with interpretation and reporting time ranging from 9-96 min. Conclusions: A genome sequencing based CVD genetic risk assessment can provide comprehensive genetic disease and genetic risk information to patients with CVD. The semi-automated and limited interpretation burden suggest that this testing approach could be scaled to support population-level initiatives.
ABSTRACT
Background: Cardiovascular disease continues to be the leading cause of death globally. Clinical practice guidelines aimed at improving disease management and positively impacting major cardiac adverse events recommend genetic testing for inherited cardiovascular conditions such as dilated cardiomyopathy (DCM), hypertrophic cardiomyopathy (HCM), long QT syndrome (LQTS), hereditary amyloidosis, and familial hypercholesterolemia (FH); however, little is known about how consistently practitioners order genetic testing for these conditions in routine clinical practice. This study aimed to assess the adoption of guideline-directed genetic testing for patients diagnosed with DCM, HCM, LQTS, hereditary amyloidosis, or FH. Methods: This retrospective cohort study captured real-world evidence of genetic testing from ICD-9-CM and ICD-10-CM codes, procedure codes, and structured text fields of de-identified patient records in the Veradigm Health Insights Ambulatory EHR Research Database linked with insurance claims data. Data analysis was conducted using an automated electronic health record analysis engine. Patient records in the Veradigm database were sourced from more than 250,000 clinicians serving over 170 million patients in outpatient primary care and specialty practice settings in the United States and linked insurance claims data from public and private insurance providers. The primary outcome measure was evidence of genetic testing within six months of condition diagnosis. Results: Between January 1, 2017, and December 31, 2021, 224,641 patients were newly diagnosed with DCM, HCM, LQTS, hereditary amyloidosis, or FH and included in this study. Substantial genetic testing care gaps were identified. Only a small percentage of patients newly diagnosed with DCM (827/101,919; 0.8%), HCM (253/15,507; 1.6%), LQTS (650/56,539; 1.2%), hereditary amyloidosis (62/1,026; 6.0%), or FH (718/49,650; 1.5%) received genetic testing. Conclusions: Genetic testing is underutilized across multiple inherited cardiovascular conditions. This real-world data analysis provides insights into the delivery of genomic healthcare in the United States and suggests genetic testing guidelines are rarely followed in practice.
ABSTRACT
Congenital diaphragmatic hernia (CDH) is a relatively common and genetically heterogeneous structural birth defect associated with high mortality and morbidity. We describe eight unrelated families with an X-linked condition characterized by diaphragm defects, variable anterior body-wall anomalies, and/or facial dysmorphism. Using linkage analysis and exome or genome sequencing, we found that missense variants in plastin 3 (PLS3), a gene encoding an actin bundling protein, co-segregate with disease in all families. Loss-of-function variants in PLS3 have been previously associated with X-linked osteoporosis (MIM: 300910), so we used in silico protein modeling and a mouse model to address these seemingly disparate clinical phenotypes. The missense variants in individuals with CDH are located within the actin-binding domains of the protein but are not predicted to affect protein structure, whereas the variants in individuals with osteoporosis are predicted to result in loss of function. A mouse knockin model of a variant identified in one of the CDH-affected families, c.1497G>C (p.Trp499Cys), shows partial perinatal lethality and recapitulates the key findings of the human phenotype, including diaphragm and abdominal-wall defects. Both the mouse model and one adult human male with a CDH-associated PLS3 variant were observed to have increased rather than decreased bone mineral density. Together, these clinical and functional data in humans and mice reveal that specific missense variants affecting the actin-binding domains of PLS3 might have a gain-of-function effect and cause a Mendelian congenital disorder.
Subject(s)
Hernias, Diaphragmatic, Congenital , Osteoporosis , Adult , Humans , Male , Animals , Mice , Hernias, Diaphragmatic, Congenital/genetics , Actins/genetics , Mutation, Missense/genetics , Osteoporosis/geneticsABSTRACT
Congenital diaphragmatic hernia (CDH) is a severe birth defect that is often accompanied by other congenital anomalies. Previous exome sequencing studies for CDH have supported a role of de novo damaging variants but did not identify any recurrently mutated genes. To investigate further the genetics of CDH, we analyzed de novo coding variants in 362 proband-parent trios including 271 new trios reported in this study. We identified four unrelated individuals with damaging de novo variants in MYRF (P = 5.3x10(-8)), including one likely gene-disrupting (LGD) and three deleterious missense (D-mis) variants. Eight additional individuals with de novo LGD or missense variants were identified from our other genetic studies or from the literature. Common phenotypes of MYRF de novo variant carriers include CDH, congenital heart disease and genitourinary abnormalities, suggesting that it represents a novel syndrome. MYRF is a membrane associated transcriptional factor highly expressed in developing diaphragm and is depleted of LGD variants in the general population. All de novo missense variants aggregated in two functional protein domains. Analyzing the transcriptome of patient-derived diaphragm fibroblast cells suggest that disease associated variants abolish the transcription factor activity. Furthermore, we showed that the remaining genes with damaging variants in CDH significantly overlap with genes implicated in other developmental disorders. Gene expression patterns and patient phenotypes support pleiotropic effects of damaging variants in these genes on CDH and other developmental disorders. Finally, functional enrichment analysis implicates the disruption of regulation of gene expression, kinase activities, intra-cellular signaling, and cytoskeleton organization as pathogenic mechanisms in CDH.
Subject(s)
Genetic Variation , Hernias, Diaphragmatic, Congenital/genetics , Membrane Proteins/genetics , Mutation , Transcription Factors/genetics , Child, Preschool , DNA Copy Number Variations , Developmental Disabilities/genetics , Female , Heart Defects, Congenital/genetics , Hernias, Diaphragmatic, Congenital/metabolism , Humans , Infant, Newborn , Longitudinal Studies , Male , Membrane Proteins/metabolism , Mutation, Missense , Phenotype , Sequence Analysis, RNA , Syndrome , Transcription Factors/metabolism , Exome Sequencing , Whole Genome SequencingABSTRACT
Turner syndrome is a sex chromosome abnormality in which a female has a single X chromosome or structurally deficient second sex chromosome. The phenotypic spectrum is broad, and atypical features prompt discussion of whether the known features of Turner syndrome should be further expanded. With the advent of clinical whole exome sequencing, there has been increased realization that some patients with genetic disorders carry a second genetic disorder, leading us to hypothesize that a "dual diagnosis" may be more common than suspected for Turner syndrome. We report five new patients with Turner syndrome and a co-occurring genetic disorder including one patient with Li-Fraumeni syndrome, Li-Fraumeni and Noonan syndrome, mosaic trisomy 8, pathogenic variant in RERE, and blepharophimosis-ptosis-epicanthanus inversus syndrome. We also undertook an extensive literature review of 147 reports of patients with Turner syndrome and a second genetic condition. A total of 47 patients (31%) had trisomy 21, followed by 36 patients (24%) had one of 11 X-linked disorders. Notably, 80% of the 147 reported patients with a dual diagnosis had mosaicism for Turner syndrome, approximately twice the frequency in the general Turner syndrome population. This article demonstrates the potential for co-occurring syndromes in patients with Turner syndrome, prompting us to recommend a search for an additional genetic disorder in Turner patients with unusual features. Knowledge of the second condition may lead to modification of treatment and/or surveillance. We anticipate that increased awareness and improved diagnostic technologies will lead to the identification of more cases of Turner syndrome with a co-occurring genetic syndrome.
Subject(s)
Population Surveillance , Turner Syndrome/diagnosis , Turner Syndrome/therapy , Adult , Child , Child, Preschool , Female , Humans , Turner Syndrome/complicationsABSTRACT
Congenital diaphragmatic hernia (CDH), characterized by malformation of the diaphragm and hypoplasia of the lungs, is one of the most common and severe birth defects, and is associated with high morbidity and mortality rates. There is growing evidence demonstrating that genetic factors contribute to CDH, although the pathogenesis remains largely elusive. Single-nucleotide polymorphisms have been studied in recent whole-exome sequencing efforts, but larger copy number variants (CNVs) have not yet been studied on a large scale in a case control study. To capture CNVs within CDH candidate regions, we developed and tested a targeted array comparative genomic hybridization platform to identify CNVs within 140 regions in 196 patients and 987 healthy controls, and identified six significant CNVs that were either unique to patients or enriched in patients compared with controls. These CDH-associated CNVs reveal high-priority candidate genes including HLX, LHX1, and HNF1B We also discuss CNVs that are present in only one patient in the cohort but have additional evidence of pathogenicity, including extremely rare large and/or de novo CNVs. The candidate genes within these predicted disease-causing CNVs form functional networks with other known CDH genes and play putative roles in DNA binding/transcription regulation and embryonic development. These data substantiate the importance of CNVs in the etiology of CDH, identify CDH candidate genes and pathways, and highlight the importance of ongoing analysis of CNVs in the study of CDH and other structural birth defects.
Subject(s)
Comparative Genomic Hybridization/methods , DNA Copy Number Variations , Genetic Markers , Hernias, Diaphragmatic, Congenital/genetics , Polymorphism, Single Nucleotide , Case-Control Studies , Humans , PrognosisABSTRACT
N-alpha-acetylation is a common co-translational protein modification that is essential for normal cell function in humans. We previously identified the genetic basis of an X-linked infantile lethal Mendelian disorder involving a c.109T>C (p.Ser37Pro) missense variant in NAA10, which encodes the catalytic subunit of the N-terminal acetyltransferase A (NatA) complex. The auxiliary subunit of the NatA complex, NAA15, is the dimeric binding partner for NAA10. Through a genotype-first approach with whole-exome or genome sequencing (WES/WGS) and targeted sequencing analysis, we identified and phenotypically characterized 38 individuals from 33 unrelated families with 25 different de novo or inherited, dominantly acting likely gene disrupting (LGD) variants in NAA15. Clinical features of affected individuals with LGD variants in NAA15 include variable levels of intellectual disability, delayed speech and motor milestones, and autism spectrum disorder. Additionally, mild craniofacial dysmorphology, congenital cardiac anomalies, and seizures are present in some subjects. RNA analysis in cell lines from two individuals showed degradation of the transcripts with LGD variants, probably as a result of nonsense-mediated decay. Functional assays in yeast confirmed a deleterious effect for two of the LGD variants in NAA15. Further supporting a mechanism of haploinsufficiency, individuals with copy-number variant (CNV) deletions involving NAA15 and surrounding genes can present with mild intellectual disability, mild dysmorphic features, motor delays, and decreased growth. We propose that defects in NatA-mediated N-terminal acetylation (NTA) lead to variable levels of neurodevelopmental disorders in humans, supporting the importance of the NatA complex in normal human development.
Subject(s)
Abnormalities, Multiple/genetics , Autism Spectrum Disorder/genetics , Genetic Predisposition to Disease , Genetic Variation , Intellectual Disability/genetics , N-Terminal Acetyltransferase A/genetics , N-Terminal Acetyltransferase E/genetics , Adolescent , Adult , Cell Line , Child , Exons/genetics , Female , Gene Expression Regulation , Humans , Male , Middle Aged , Mutation/genetics , N-Terminal Acetyltransferase A/metabolism , N-Terminal Acetyltransferase E/metabolism , Pedigree , Phenotype , RNA, Messenger/genetics , RNA, Messenger/metabolism , Saccharomyces cerevisiae/metabolismABSTRACT
OBJECTIVE: Laparoscopic cholecystectomy is the first-choice treatment for symptomatic cholelithiasis. Though generally safe, this procedure is not without complications, with bleeding the most frequent cause of conversion to open cholecystectomy. Oxidized regenerated cellulose (ORC) added to conventional hemostatic strategies, is widely used to control bleeding during surgery despite limited evidence supporting its use. This retrospective study analyzed patients undergoing laparoscopic cholecystectomy in an Italian center over a 16-month period, between October 2014 and February 2016, who experienced uncontrollable bleeding despite the use of conventional hemostatic strategies, requiring the addition of ORC gauze (Emosist®). RESULTS: Of the 530 patients who underwent laparoscopic cholecystectomy, 24 (4.5%) had uncontrollable bleeding from the liver bed. Of these, 62.5% had acute cholecystitis and 33.3% chronic cholecystitis; 1 patient was diagnosed with gallbladder carcinoma, postoperatively. Most patients had comorbidities, 16.7% had liver cirrhosis, and 37.5% used oral anticoagulants. The application of ORC rapidly controlled bleeding in all patients. Patients were discharged after a mean duration of 2.2 days. ORC was easy to use and well tolerated. Bleeding complications remain a relevant issue in laparoscopic cholecystectomy. ORC was able to promptly stop bleeding not adequately controlled by conventional methods and appears, therefore, to be a useful hemostat.
Subject(s)
Blood Loss, Surgical/prevention & control , Cellulose, Oxidized/therapeutic use , Cholecystectomy, Laparoscopic/adverse effects , Cholelithiasis/surgery , Hemostasis/physiology , Hemostatic Techniques , Outcome Assessment, Health Care , Adolescent , Adult , Aged , Aged, 80 and over , Cholecystectomy, Laparoscopic/methods , Female , Humans , Male , Middle Aged , Retrospective Studies , Young AdultABSTRACT
PURPOSE: Measurement and monitoring of the quality of care using a core set of quality measures are increasing in health service research. Although administrative databases include limited clinical data, they offer an attractive source for quality measurement. The purpose of this study, therefore, was to evaluate the completeness of different administrative data sources compared to a clinical survey in evaluating rectal cancer cases. METHODS: Between May 2012 and November 2014, a clinical survey was done on 498 Lombardy patients who had rectal cancer and underwent surgical resection. These collected data were compared with the information extracted from administrative sources including Hospital Discharge Dataset, drug database, daycare activity data, fee-exemption database, and regional screening program database. The agreement evaluation was performed using a set of 12 quality indicators. RESULTS: Patient complexity was a difficult indicator to measure for lack of clinical data. Preoperative staging was another suboptimal indicator due to the frequent missing administrative registration of tests performed. The agreement between the 2 data sources regarding chemoradiotherapy treatments was high. Screening detection, minimally invasive techniques, length of stay, and unpreventable readmissions were detected as reliable quality indicators. Postoperative morbidity could be a useful indicator but its agreement was lower, as expected. CONCLUSIONS: Healthcare administrative databases are large and real-time collected repositories of data useful in measuring quality in a healthcare system. Our investigation reveals that the reliability of indicators varies between them. Ideally, a combination of data from both sources could be used in order to improve usefulness of less reliable indicators.
Subject(s)
Databases, Factual/standards , Delivery of Health Care/standards , Health Surveys/standards , Primary Health Care/standards , Rectal Neoplasms/therapy , Databases, Factual/statistics & numerical data , Delivery of Health Care/statistics & numerical data , Health Surveys/statistics & numerical data , Humans , Italy , Primary Health Care/methods , Primary Health Care/statistics & numerical data , Prospective Studies , Quality Indicators, Health Care/standards , Quality Indicators, Health Care/statistics & numerical data , Rectal Neoplasms/diagnosis , Reproducibility of ResultsABSTRACT
Congenital Diaphragmatic Hernia (CDH) is a common and often lethal birth defect characterized by diaphragmatic structural defects and pulmonary hypoplasia. CDH is isolated in 60% of newborns, but may also be part of a complex phenotype with additional anomalies. We performed whole exome sequencing (WES) on 87 individuals with isolated or complex CDH and on their unaffected parents, to assess the contribution of de novo mutations in the etiology of diaphragmatic and pulmonary defects and to identify new candidate genes. A combined analysis with 39 additional trios with complex CDH, previously published, revealed a significant genome-wide burden of de novo variants compared to background mutation rate and 900 control trios. We identified an increased burden of likely gene-disrupting (LGD, i.e. nonsense, frameshift, and canonical splice site) and predicted deleterious missense (D-mis) variants in complex and isolated CDH patients. Overall, an excess of predicted damaging de novo LGD and D-mis variants relative to the expected frequency contributed to 21% of complex cases and 12% of isolated CDH cases. The burden of de novo variants was higher in genes expressed in the developing mouse diaphragm and heart. Some overlap with genes responsible for congenital heart defects and neurodevelopmental disorders was observed in CDH patients within our cohorts. We propose that de novo variants contribute significantly to the development of CDH.
Subject(s)
Genome-Wide Association Study , Hernias, Diaphragmatic, Congenital/genetics , Gene Expression Regulation, Developmental , Humans , Protein BindingABSTRACT
Congenital diaphragmatic hernia (CDH) is one of the most common and lethal congenital anomalies, and significant evidence is available in support of a genetic contribution to its etiology, including single-gene knockout mice associated with diaphragmatic defects, rare monogenetic disorders in humans, familial aggregation, and association of CDH with chromosomal abnormalities. Structural lung defects in the form of lung hypoplasia are almost invariably seen in patients with CDH and frequently in animal models of this condition. Better understanding of the mechanisms of pulmonary defects in CDH has the potential for creating targeted therapies, particularly in postnatal stages, when therapeutics can have maximum clinical impact on the surviving cohorts. Successful treatment of CDH is dependent on the integration of human genomic and genetic data with developmental expression profiling, mouse knockouts, and gene network and pathway modeling, which have generated a large number of candidate genes and pathways for follow-up studies. In particular, defective alveolarization appears to be a common and potentially actionable phenotype in both patients and animal models.
Subject(s)
Chromosome Aberrations , Hernias, Diaphragmatic, Congenital/genetics , Hernias, Diaphragmatic, Congenital/pathology , Animals , Diaphragm/embryology , Diaphragm/pathology , Disease Models, Animal , Female , Hernias, Diaphragmatic, Congenital/therapy , Humans , Infant , Lung/embryology , Lung/pathology , Mice , Mice, KnockoutABSTRACT
BACKGROUND: Type IV collagen is the main component of the basement membrane that gives strength to the blood-gas barrier (BGB). In mammals, the formation of a mature BGB occurs primarily after birth during alveologenesis and requires the formation of septa from the walls of the saccule. In contrast, in avians, the formation of the BGB occurs rapidly and prior to hatching. Mutation in basement membrane components results in an abnormal alveolar phenotype; however, the specific role of type IV collagen in regulating alveologenesis remains unknown. RESULTS: We have performed a microarray expression analysis in late chick lung development and found that COL4A1 and COL4A2 were among the most significantly upregulated genes during the formation of the avian BGB. Using mouse models, we discovered that mutations in murine Col4a1 and Col4a2 genes affected the balance between lung epithelial progenitors and differentiated cells. Mutations in Col4a1 derived from the vascular component were sufficient to cause defects in vascular development and the BGB. We also show that Col4a1 and Col4a2 mutants displayed disrupted myofibroblast proliferation, differentiation and migration. Lastly, we revealed that addition of type IV collagen protein induced myofibroblast proliferation and migration in monolayer culture and increased the formation of mesenchymal-epithelial septal-like structures in co-culture. CONCLUSIONS: Our study showed that type IV collagen and, therefore the basement membrane, play fundamental roles in coordinating alveolar morphogenesis. In addition to its role in the formation of epithelium and vasculature, type IV collagen appears to be key for alveolar myofibroblast development by inducing their proliferation, differentiation and migration throughout the developing septum.
Subject(s)
Collagen Type IV/metabolism , Endothelial Cells/cytology , Epithelial Cells/cytology , Morphogenesis , Peptide Fragments/metabolism , A549 Cells , Animals , Basement Membrane/metabolism , Cell Differentiation , Cell Movement , Cell Proliferation , Cells, Cultured , Chick Embryo , Coculture Techniques , Collagen Type IV/genetics , Fibroblasts/cytology , Fibroblasts/metabolism , Humans , Lung/cytology , Mice , Mice, Knockout , Microarray Analysis , Mutation , Myofibroblasts/cytology , Peptide Fragments/genetics , Up-RegulationABSTRACT
COUP-TFII (NR2F2) is mapped to the 15q26 deletion hotspot associated with the common and highly morbid congenital diaphragmatic hernia (CDH). Conditional homozygous deletions of COUP-TFII in mice result in diaphragmatic defects analogous to the human Bochdalek-type hernia phenotype. Despite evidence from animal models however, mutations in the coding sequence of COUP-TFII have not been reported in patients, prompting the speculation that additional coding or non-coding sequences in the 15q26 locus are necessary for diaphragmatic hernias to develop. In this report, we describe a case of a patient with a heterozygous de novo COUP-TFII frameshift mutation, presenting with CDH and an atrial septal defect. The p.Pro33AlafsTer77 mutation specifically disrupts protein isoform 1 which contains the DNA binding domain. In addition, we review other COUP-TFII sequence variations and deletions that have been described in cases of CDH. We conclude that COUP-TFII mutations can cause diaphragmatic hernias, and should be included in the differential diagnosis of CDH patients, particularly those with comorbid congenital heart defects. © 2016 Wiley Periodicals, Inc.
Subject(s)
COUP Transcription Factor II/genetics , Frameshift Mutation , Genetic Association Studies , Hernias, Diaphragmatic, Congenital/diagnosis , Hernias, Diaphragmatic, Congenital/genetics , Phenotype , Abnormalities, Multiple/diagnosis , Abnormalities, Multiple/genetics , Alleles , DNA Mutational Analysis , Female , Genotype , Humans , Infant, Newborn , Male , Pedigree , Polymorphism, Single NucleotideABSTRACT
Congenital diaphragmatic hernia is associated with pulmonary hypoplasia and respiratory distress, which result in high mortality and morbidity. Although several transgenic mouse models of lung hypoplasia exist, the role of miRNAs in this phenotype is incompletely characterized. In this study, we assessed microRNA expression levels during the pseudoglandular to canalicular phase transition of normal human fetal lung development. At this critical time, when the distal respiratory portion of the airways begins to form, microarray analysis showed that the most significantly differentially expressed miRNA was miR-449a. Prediction algorithms determined that N-myc is a target of miR-449a and identified the likely miR-449a:N-myc binding sites, confirmed by luciferase assays and targeted mutagenesis. Functional ex vivo knock-down in organ cultures of murine embryonic lungs, as well as in ovo overexpression in avian embryonic lungs, suggested a role for miR-449a in distal epithelial proliferation. Finally, miR-449a expression was found to be abnormal in rare pulmonary specimens of human fetuses with Congenital Diaphragmatic Hernia in the pseudoglandular or canalicular phase. This study confirms the conserved role of miR-449a for proper pulmonary organogenesis, supporting the delicate balance between expansion of progenitor cells and their terminal differentiation, and proposes the potential involvement of this miRNA in human pulmonary hypoplasia.
Subject(s)
Lung/embryology , Lung/metabolism , MicroRNAs/genetics , Organogenesis/genetics , 3' Untranslated Regions , Animals , Base Sequence , Binding Sites , Cell Differentiation/genetics , Cell Proliferation , Chickens , Gene Expression Regulation, Developmental , Humans , Lung/pathology , Mice , MicroRNAs/chemistry , Oncogene Proteins/chemistry , Oncogene Proteins/genetics , RNA Interference , RNA, Messenger/chemistry , RNA, Messenger/genetics , Transcription, GeneticABSTRACT
Congenital diaphragmatic hernia (CDH) is a common and severe birth defect. Despite its clinical significance, the genetic and developmental pathways underlying this disorder are incompletely understood. In this study, we report a catalog of variants detected by a whole exome sequencing study on 275 individuals with CDH. Predicted pathogenic variants in genes previously identified in either humans or mice with diaphragm defects are enriched in our CDH cohort compared with 120 size-matched random gene sets. This enrichment was absent in control populations. Variants in these critical genes can be found in up to 30.9% of individuals with CDH. In addition, we filtered variants by using genes derived from regions of recurrent copy number variations in CDH, expression profiles of the developing diaphragm, protein interaction networks expanded from the known CDH-causing genes, and prioritized genes with ultrarare and highly disruptive variants, in 11.3% of CDH patients. These strategies have identified several high priority genes and developmental pathways that likely contribute to the CDH phenotype. These data are valuable for comparison of candidate genes generated from whole exome sequencing of other CDH cohorts or multiplex kindreds and provide ideal candidates for further functional studies. Furthermore, we propose that these genes and pathways will enhance our understanding of the heterogeneous molecular etiology of CDH.
Subject(s)
Hernias, Diaphragmatic, Congenital/etiology , Hernias, Diaphragmatic, Congenital/genetics , Animals , Cohort Studies , Computational Biology , DNA Copy Number Variations , Diaphragm/embryology , Exome , Genetic Variation , Hernias, Diaphragmatic, Congenital/embryology , Humans , Mice , Protein Interaction MapsABSTRACT
Chromosome 8p23.1 is a common hotspot associated with major congenital malformations, including congenital diaphragmatic hernia (CDH) and cardiac defects. We present findings from high-resolution arrays in patients who carry a loss (n = 18) or a gain (n = 1) of sub-band 8p23.1. We confirm a region involved in both diaphragmatic and heart malformations. Results from a novel CNVConnect algorithm, prioritizing protein-protein interactions between products of genes in the 8p23.1 hotspot and products of previously known CDH causing genes, implicated GATA4, NEIL2, and SOX7 in diaphragmatic defects. Sequence analysis of these genes in 226 chromosomally normal CDH patients, as well as in a small number of deletion 8p23.1 patients, showed rare unreported variants in the coding region; these may be contributing to the diaphragmatic phenotype. We also demonstrated that two of these three genes were expressed in the E11.5-12.5 primordial mouse diaphragm, the developmental stage at which CDH is thought to occur. This combination of bioinformatics and expression studies can be applied to other chromosomal hotspots, as well as private microdeletions or microduplications, to identify causative genes and their interaction networks.
Subject(s)
Hernias, Diaphragmatic, Congenital , Animals , Chromosome Deletion , Chromosomes, Human, Pair 8/genetics , Chromosomes, Human, Pair 8/metabolism , DNA/blood , DNA/genetics , DNA Glycosylases/genetics , DNA-(Apurinic or Apyrimidinic Site) Lyase/genetics , Female , GATA4 Transcription Factor/genetics , Heart Defects, Congenital/blood , Heart Defects, Congenital/genetics , Heart Defects, Congenital/metabolism , Hernia, Diaphragmatic/blood , Hernia, Diaphragmatic/genetics , Hernia, Diaphragmatic/metabolism , Humans , Karyotyping , Mice , Mice, Inbred C57BL , Phenotype , Pregnancy , Protein Interaction Maps , SOXF Transcription Factors/geneticsABSTRACT
Congenital diaphragmatic hernia (CDH) is a common (1 in 3,000 live births) major congenital malformation that results in significant morbidity and mortality. The discovery of CDH loci using standard genetic approaches has been hindered by its genetic heterogeneity. We hypothesized that gene expression profiling of developing embryonic diaphragms would help identify genes likely to be associated with diaphragm defects. We generated a time series of whole-transcriptome expression profiles from laser captured embryonic mouse diaphragms at embryonic day (E)11.5 and E12.5 when experimental perturbations lead to CDH phenotypes, and E16.5 when the diaphragm is fully formed. Gene sets defining biologically relevant pathways and temporal expression trends were identified by using a series of bioinformatic algorithms. These developmental sets were then compared with a manually curated list of genes previously shown to cause diaphragm defects in humans and in mouse models. Our integrative filtering strategy identified 27 candidates for CDH. We examined the diaphragms of knockout mice for one of the candidate genes, pre-B-cell leukemia transcription factor 1 (Pbx1), and identified a range of previously undetected diaphragmatic defects. Our study demonstrates the utility of genetic characterization of normal development as an integral part of a disease gene identification and prioritization strategy for CDH, an approach that can be extended to other diseases and developmental anomalies.
Subject(s)
Embryo, Mammalian/metabolism , Embryo, Mammalian/pathology , Genetic Association Studies , Hernias, Diaphragmatic, Congenital , Transcriptome/genetics , Animals , Diaphragm/embryology , Diaphragm/metabolism , Diaphragm/pathology , Gene Expression Regulation, Developmental , Hernia, Diaphragmatic/genetics , Hernia, Diaphragmatic/pathology , Homeodomain Proteins/metabolism , Lasers , Mesoderm/embryology , Mesoderm/metabolism , Mesoderm/pathology , Mice , Mice, Knockout , Models, Biological , Pre-B-Cell Leukemia Transcription Factor 1 , Signal Transduction/genetics , Time Factors , Transcription Factors/deficiency , Transcription Factors/metabolism , Transcription, GeneticABSTRACT
Cytogenetic and molecular cytogenetic studies demonstrate association between congenital diaphragmatic hernia (CDH) and chromosome 1q41q42 deletions. In this study, we screened a large CDH cohort (N=179) for microdeletions in this interval by the multiplex ligation-dependent probe amplification (MLPA) technique, and also sequenced two candidate genes located therein, dispatched 1 (DISP1) and homo sapiens H2.0-like homeobox (HLX). MLPA analysis verified deletions of this region in two cases, an unreported patient with a 46,XY,del(1)(q41q42.13) karyotype and a previously reported patient with a Fryns syndrome phenotype [Kantarci et al., 2006]. HLX sequencing showed a novel but maternally inherited single nucleotide variant (c.27C>G) in a patient with isolated CDH, while DISP1 sequencing revealed a mosaic de novo heterozygous substitution (c.4412C>G; p.Ala1471Gly) in a male with a left-sided Bochdalek hernia plus multiple other anomalies. Pyrosequencing demonstrated the mutant allele was present in 43%, 12%, and 4.5% of the patient's lymphoblastoid, peripheral blood lymphocytes, and saliva cells, respectively. We examined Disp1 expression at day E11.5 of mouse diaphragm formation and confirmed its presence in the pleuroperitoneal fold, as well as the nearby lung which also expresses Sonic hedgehog (Shh). Our report describes the first de novo DISP1 point mutation in a patient with complex CDH. Combining this finding with Disp1 embryonic mouse diaphragm and lung tissue expression, as well as previously reported human chromosome 1q41q42 aberrations in patients with CDH, suggests that DISP1 may warrant further consideration as a CDH candidate gene.