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Background The high risks for childhood respiratory diseases are associated with exposure to ambient air pollution. However, there are few studies that have explored the association between air pollution exposure and respiratory diseases among young children (particularly aged 0–2 years) based on the entire population in a megalopolis. Methods Daily hospital admission records were obtained from 54 municipal hospitals in Wuhan city, China. We included all children (aged 0–2 years) hospitalized with respiratory diseases between January 2017 and December 2018. Individual air pollution exposure assessment was used in Land Use Regression model and inverse distance weighted. Case-crossover design and conditional logistic regression models were adopted to estimate the hospitalization risk associated with air pollutants. Results We identified 62,425 hospitalizations due to respiratory diseases, of which 36,295 were pneumonia. Particulate matter with an aerodynamic diameter less than 2.5 μm (PM2.5) and nitrogen dioxide (NO2) were significantly associated with respiratory diseases and pneumonia. ORs of pneumonia were 1.0179 (95% CI 1.0097–1.0260) for PM2.5 and 1.0131 (95% CI 1.0042–1.0220) for NO2 at lag 0–7 days. Subgroup analysis suggested that NO2, Ozone (O3) and sulfur dioxide (SO2) only showed effects on pneumonia hospitalizations on male patients, but PM2.5 had effects on patients of both genders. Except O3, all pollutants were strongly associated with pneumonia in cold season. In addition, children who aged elder months and who were in central urban areas had a higher hospitalization risk. Conclusions Air pollution is associated with higher hospitalization risk for respiratory diseases, especially pneumonia, among young children, and the risk is related to gender, month age, season and residential location.

Pulmonary arterial hypertension (PAH) refers to a rare, progressive disorder that is characterized by occlusive pulmonary vascular remodeling, resulting in increased pulmonary arterial pressure, right-sided heart failure, and eventual death. Emerging evidence from genetic investigations of pediatric-onset PAH highlights the strong genetic basis underpinning PAH, and deleterious variants in multiple genes have been found to cause PAH. Nevertheless, PAH is of substantial genetic heterogeneity, and the genetic defects underlying PAH in the overwhelming majority of cases remain elusive. In this investigation, a consanguineous family suffering from PAH transmitted as an autosomal-dominant trait was identified. Through whole-exome sequencing and bioinformatic analyses as well as Sanger sequencing analyses of the PAH family, a novel heterozygous SOX17 mutation, NM_022454.4: c.379C>T; p. (Gln127*), was found to co-segregate with the disease in the family, with complete penetrance. The nonsense mutation was neither observed in 612 unrelated healthy volunteers nor retrieved in the population genetic databases encompassing the Genome Aggregation Database, the Exome Aggregation Consortium database, and the Single Nucleotide Polymorphism database. Biological analyses using a dual-luciferase reporter assay system revealed that the Gln127*-mutant SOX17 protein lost the ability to transcriptionally activate its target gene NOTCH1. Moreover, the Gln127*-mutant SOX17 protein exhibited no inhibitory effect on the function of CTNNB1-encode β-catenin, which is a key player in vascular morphogenesis. This research firstly links SOX17 loss-of-function mutation to familial PAH, which provides novel insight into the molecular pathogenesis of PAH, suggesting potential implications for genetic and prognostic risk evaluation as well as personalized prophylaxis of the family members affected with PAH.

Congenital heart defect (CHD) is the most common type of birth defect in humans and a leading cause of infant morbidity and mortality. Previous studies have demonstrated that genetic defects play a pivotal role in the pathogenesis of CHD. However, the genetic basis of CHD remains poorly understood due to substantial genetic heterogeneity. In this study, the coding exons and splicing boundaries of the NR2F2 gene, which encodes a pleiotropic transcription factor required for normal cardiovascular development, were sequenced in 168 unrelated patients with CHD, and a novel mutation (c.247G > T, equivalent to p.G83X) was detected in a patient with double outlet right ventricle as well as ventricular septal defect. Genetic scanning of the mutation carrier's relatives available showed that the mutation was present in all affected family members but absent in unaffected family members. Analysis of the index patient's pedigree displayed that the mutation co-segregated with CHD, which was transmitted as an autosomal dominant trait with complete penetrance. The nonsense mutation was absent in 230 unrelated, ethnically-matched healthy individuals used as controls. Functional deciphers by using a dual-luciferase reporter assay system revealed that the mutant NR2F2 protein had no transcriptional activity as compared with its wild-type counterpart. Furthermore, the mutation abrogated the synergistic transcriptional activation between NR2F2 and GATA4, another core cardiac transcription factor associated with CHD. This study firstly associates NR2F2 loss-of-function mutation with an increased susceptibility to double outlet right ventricle in humans, which provides further significant insight into the molecular mechanisms underpinning CHD, suggesting potential implications for genetic counseling of CHD families and personalized treatment of CHD patients.

Congenital heart disease (CHD) is the most common type of developmental abnormality in humans, and is a leading cause for substantially increased morbidity and mortality in affected individuals. Increasing studies demonstrates a pivotal role of genetic defects in the pathogenesis of CHD, and presently mutations in more than 60 genes have been associated with CHD. Nevertheless, CHD is of pronounced genetic heterogeneity, and the genetic basis underpinning CHD in a large proportion of patients remains unclear. In the present study, the whole coding exons and splicing donors/acceptors of the MEF2C gene, which codes for a transcription factor essential for normal cardiovascular development, were sequenced in 200 unrelated patients affected with CHD, and a novel heterozygous missense mutation, p.L38P, was identified in an index patient with patent ductus arteriosus (PDA) and ventricular septal defect (VSD). Genetic scan of the mutation carrier's family members available showed that the mutation was present in all affected family members but absent in unaffected family members. Analysis of the proband's pedigree revealed that the mutation co-segregated with PDA, which was transmitted as an autosomal dominant trait with complete penetrance. The mutation changed the amino acid that was completely conserved evolutionarily, and did not exist in 300 unrelated, ethnically-matched healthy individuals used as controls. Functional deciphers by using a dual-luciferase reporter assay system unveiled that the mutant MEF2C protein had a significantly reduced transcriptional activity. Furthermore, the mutation significantly diminished the synergistic activation between MEF2C and GATA4, another cardiac core transcription factor that has been causally linked to CHD. In conclusion, this is the first report on the association of a MEF2C loss-of-function mutation with an increased vulnerability to CHD in humans, which provides novel insight into the molecular mechanisms underlying CHD, implying potential implications for early diagnosis and timely prophylaxis of CHD.

Congenital heart disease (CHD) is the most common form of birth defect in humans, and remains a leading non‑infectious cause of infant mortality worldwide. An increasing number of studies have demonstrated that genetic defects serve a pivotal role in the pathogenesis of CHD, and mutations in >60 genes have been causally associated with CHD. CHD is a heterogeneous disease and the genetic basis of CHD in the majority of patients remains poorly understood. In the present study, the coding exons and flanking introns of the mesoderm posterior 1 (MESP1) gene, which encodes a basic helix‑loop‑helix transcription factor required for normal cardiovascular development, were sequenced in 178 unrelated patients with CHD. The available relatives of the index patient carrying an identified mutation and 200 unrelated, ethnically‑matched healthy individuals, who were used as controls, were genotyped for MESP1. The functional characteristics of the MESP1 mutation were determined using a dual‑luciferase reporter assay system. As a result, a novel de novo heterozygous MESP1 mutation, p.Q118X, was identified in an index patient with double outlet right ventricle (DORV) and a ventricular septal defect. The nonsense mutation was absent in the 400 reference chromosomes and the altered amino acid was completely conserved evolutionarily across species. Functional assays indicated that the mutant MESP1 protein had no transcriptional activity when compared with its wild‑type counterpart. The present study firstly provided experimental evidence supporting the concept that a MESP1 loss‑of‑function mutation may contribute to the development of DORV in humans, which presents a significant insight into the molecular pathogenesis of CHD. The results highlight the potential implications for the genetic counseling and personalized treatment of patients with CHD.

Congenital heart defects (CHDs), a wide variety of developmental abnormalities in the structures of the heart and the great thoracic blood vessels, are the most common form of birth defect in humans worldwide. CHDs are accountable for substantial morbidity and are still the leading cause of birth defect‑related deaths. Recent studies have demonstrated the pivotal roles of genetic defects in the pathogenesis of CHDs, and a great number of genetic mutations have been associated with CHDs. Nevertheless, CHDs are a genetically heterogeneous disorder and the genetic basis underlying CHDs in an overwhelming majority of cases remains unclear. In the present study, the coding exons and flanking introns of the heart and neural crest derivatives expressed transcript 1 (HAND1) gene, which encodes a basic helix‑loop‑helix transcription factor crucial for cardiovascular development, were sequenced in 158 unrelated patients with CHDs, and a de novo heterozygous mutation, p.K132X, was identified in a patient with double outlet right ventricle (DORV), as well as ventricular septal defect. The nonsense mutation, which was predicted to produce a truncated HAND1 protein lacking 84 carboxyl‑terminal amino acids, was absent in 600 control chromosomes. Functional analyses revealed that the HAND1 K132X mutant had no transcriptional activity. Furthermore, the mutation disrupted the synergistic activation between HAND1 and GATA binding protein 4 (GATA4), another cardiac core transcription factor causally linked to CHDs. To the best of our knowledge, this is the first report on the association of HAND1 loss‑of‑function mutation with an enhanced susceptibility to DORV in humans. These findings expand the phenotypic spectrum linked to HAND1 mutations, suggesting potential implications for the development of novelo prophylactic and therapeutic strategies for DORV.

Occurring in about 1% of all live births, congenital heart defects (CHDs) represent the most frequent type of developmental abnormality and account for remarkably increased infant morbidity and mortality. Aggregating studies demonstrate that genetic components have a key role in the occurrence of CHDs. Nevertheless, due to pronounced genetic heterogeneity, the genetic causes of CHDs remain unclear in most patients. In this research, 114 unrelated patients affected with CHDs and 218 unrelated individuals without CHDs served as controls were recruited. The coding regions and splicing donors/acceptors of the ISL1 gene, which codes for a transcription factor required for proper cardiovascular development, were screened for mutations by sequencing in all study participants. The functional characteristics of an identified ISL1 mutation were delineated with a dual-luciferase reporter assay system. As a result, a new heterozygous ISL1 mutation, NM_002202.2: c.225CG; p. (Tyr75*), was discovered in an index patient with double outlet right ventricle and ventricular septal defect. Analysis of the proband's family unveiled that the mutation co-segregated with the CHD phenotype. The nonsense mutation was absent in the 436 control chromosomes. Biological analysis showed that the mutant ISL1 protein had no transcriptional activity. Furthermore, the mutation nullified the synergistic activation between ISL1 and TBX20, another CHD-associated transcription factor. This research for the first time links an ISL1 loss-of-function mutation to double outlet right ventricle in humans, which adds insight to the molecular pathogenesis underpinning CHDs, suggesting potential implications for timely personalized management of CHD patients.

Congenital heart defect (CHD) represents the most prevalent birth defect, and accounts for substantial morbidity and mortality in humans. Aggregating evidence demonstrates the genetic basis for CHD. However, CHD is a heterogeneous disease, and the genetic determinants underlying CHD in most patients remain unknown. In the present study, a cohort of 186 unrelated cases with CHD and 300 unrelated control individuals were recruited. The coding exons and flanking introns of the MEF2C gene, which encodes a transcription factor crucial for proper cardiovascular development, were sequenced in all study participants. The functional effect of an identified MEF2C mutation was characterized using a dual-luciferase reporter assay system. As a result, a novel heterozygous MEF2C mutation, p.R15C, was detected in an index patient with congenital double outlet right ventricle (DORV) as well as ventricular septal defect. Analysis of the proband's pedigree showed that the mutation co-segregated with CHD with complete penetrance. The missense mutation, which changed the evolutionarily conserved amino acid, was absent in 300 control individuals. Functional deciphers revealed that the mutant MEF2C protein had a significantly decreased transcriptional activity. Furthermore, the mutation significantly reduced the synergistic activation between MEF2C and GATA4, another transcription factor linked to CHD. This study firstly associates MEF2C loss-of-function mutation with DORV in humans, which provides novel insight into the molecular pathogenesis of CHD, suggesting potential implications for genetic counseling and personalized treatment of CHD patients.

Congenital heart disease (CHD), the most prevalent birth defect in humans worldwide, is still a leading non‑infectious cause of infant morbidity and mortality. Increasing evidence demonstrates that genetic risk factors play a key role in the pathogenesis of CHD, and more than 50 genes have been linked to various types of CHD. Nevertheless, CHD is a heterogeneous disorder and the genetic components underpinning CHD in an overwhelming majority of cases remain unknown. In the present study, the entire coding exons and flanking introns of the TBX20 gene, which codes for a T-box transcription factor essential for the proper development of the heart, were sequenced in a cohort of 146 unrelated patients with CHD. The available relatives of the index patient harboring an identified mutation and 200 unrelated ethnically matched healthy individuals used as the controls were also genotyped for TBX20. The functional characteristics of the TBX20 mutation were assayed by using a dual-luciferase reporter assay system. As a result, a novel heterozygous TBX20 mutation, p.R143W, was identified in an index patient with double outlet right ventricle (DORV). Genetic analyses of the pedigree of the proband revealed that in the family, the mutation co-segregated with DORV transmitted in an autosomal dominant pattern with complete penetrance. The missense mutation was absent in 400 control chromosomes and the altered amino acid was completely conserved evolutionarily across species. Functional analysis revealed that mutant TBX20 had a significantly diminished transcriptional activity compared with its wild-type counterpart. To the best of our knowledge, this study is the first to report the association of TBX20 loss-of-function mutation with increased susceptibility to DORV in humans, which provides novel insight into the molecular mechanisms responsible for CHD, suggesting potential implications for the antenatal prophylaxis of CHD.

Summary Background Ventricular septal defect (VSD) is the most prevalent type of congenital heart disease and is a major cause of substantial morbidity and mortality in infants. Accumulating evidence implicates genetic defects, especially in cardiac transcription factors, in the pathogenesis of VSD. However, VSD is genetically heterogeneous and the genetic determinants for VSD in most patients remain to be identified. Material/Methods A cohort of 230 unrelated patients with congenital VSD was included in the investigation. A total of 200 unrelated ethnically matched healthy individuals were recruited as controls. The entire coding region of GATA4, a gene encoding a zinc-finger transcription factor essential for normal cardiac morphogenesis, was sequenced initially in 230 unrelated VSD patients. The available relatives of the mutation carriers and 200 control subjects were subsequently genotyped for the presence of identified mutations. Results Four heterozygous missense GATA4 mutations of p.Q55R, p.G96R, p.N197S, and p.K404R were identified in 4 unrelated patients with VSD. These mutations were not detected in 200 control individuals nor described in the human SNP database. Genetic analysis of the relatives of the mutation carriers showed that in each family the mutation co-segregated with VSD. Conclusions These findings expand the mutation spectrum of GATA4 linked to VSD and provide new insight into the molecular etiology responsible for VSD, suggesting potential implications for the genetic diagnosis and gene-specific therapy for VSD.

Congenital heart disease (CHD), the most common type of birth defect, is still the leading non-infectious cause of infant morbidity and mortality in humans. Aggregating evidence demonstrates that genetic defects are involved in the pathogenesis of CHD. However, CHD is genetically heterogeneous and the genetic components underpinning CHD in an overwhelming majority of patients remain unclear. In the present study, the coding exons and flanking introns of the PITX2 gene, which encodes a paired-like homeodomain transcription factor 2essential for cardiovascular morphogenesis as well as maxillary facial development, was sequenced in 196 unrelated patients with CHD and subsequently in the mutation carrier's family members available. As a result, a novel heterozygous PITX2 mutation, p.Q102X for PITX2a, or p.Q148X for PITX2b, or p.Q155X for PITX2c, was identified in a family with endocardial cushion defect (ECD) and Axenfeld-Rieger syndrome (ARS). Genetic analysis of the pedigree showed that the nonsense mutation co-segregated with ECD and ARS transmitted in an autosomal dominant pattern with complete penetrance. The mutation was absent in 800 control chromosomes from an ethnically matched population. Functional analysis by using a dual-luciferase reporter assay system revealed that the mutant PITX2 had no transcriptional activity and that the mutation eliminated synergistic transcriptional activation between PITX2 and NKX2.5, another transcription factor pivotal for cardiogenesis. To our knowledge, this is the first report on the association of PITX2 loss-of-function mutation with increased susceptibility to ECD and ARS. The findings provide novel insight into the molecular mechanisms underpinning ECD and ARS, suggesting the potential implications for the antenatal prophylaxis and personalized treatment of CHD and ARS.

Congenital heart disease (CHD) is the most prevalent type of birth defect in humans and is the leading non-infectious cause of infant death worldwide. There is a growing body of evidence demonstrating that genetic defects play an important role in the pathogenesis of CHD. However, CHD is a genetically heterogeneous disease and the genetic basis underpinning CHD in an overwhelming majority of patients remains unclear. In this study, the coding exons and splice junction sites of the TBX1 gene, which encodes a T-box homeodomain transcription factor essential for proper cardiovascular morphogenesis, were sequenced in 230 unrelated children with CHD. The available family members of the index patient carrying an identified mutation and 200 unrelated ethnically matched healthy individuals used as controls were subsequently genotyped for TBX1. The functional effect of the TBX1 mutation was predicted by online program MutationTaster and characterized by using a dual-luciferase reporter assay system. As a result, a novel heterozygous TBX1 mutation, p.Q277X, was identified in an index patient with double outlet right ventricle (DORV) and ventricular septal defect (VSD). Genetic analysis of the proband’s available relatives showed that the mutation co-segregated with CHD transmitted in an autosomal dominant pattern with complete penetrance. The nonsense mutation, which was absent in 400 control chromosomes, altered the amino acid that was completely conserved evolutionarily across species and was predicted to be disease-causing by MutationTaster. Biochemical analysis revealed that Q277X-mutant TBX1 lost transcriptional activating function when compared with its wild-type counterpart. This study firstly associates TBX1 loss-of-function mutation with enhanced susceptibility to DORV and VSD in humans, which provides novel insight into the molecular mechanism underlying CHD and suggests potential implications for the development of new preventive and therapeutic strategies for CHD.

Tetraology of Fallot (TOF) is the most common form of cyanotic congenital heart disease and is a major cause of significant morbidity and mortality. Emerging evidence demonstrates that genetic risk factors are involved in the pathogenesis of TOF. However, TOF is genetically heterogeneous and the genetic defects responsible for TOF remain largely unclear. In the present study, the whole coding region of the GATA5 gene, which encodes a zinc-finger transcription factor essential for cardiogenesis, was sequenced in 130 unrelated patients with TOF. The relatives of the index patients harboring the identified mutations and 200 unrelated control individuals were subsequently genotyped. The functional characteristics of the mutations were analyzed using a luciferase reporter assay system. As a result, 2 novel heterozygous GATA5 mutations, p.R187G and p.H207R, were identified in 2 families with autosomal dominantly inherited TOF, respectively. The variations were absent in 400 control alleles and the altered amino acids were completely conserved evolutionarily. Functional analysis showed that the GATA5 mutants were associated with significantly decreased transcriptional activation compared with their wild-type counterpart. To our knowledge, this is the first report on the association of GATA5 loss-of-function mutations with TOF, suggesting potential implications for the early prophylaxis and allele-specific therapy of human TOF.

The ventriculoseptal defect (VSD) is the most common form of congenital heart disease and a leading noninfectious cause of infant mortality. Growing evidence demonstrates that genetic defects are associated with congenital VSD. Nevertheless, VSD is genetically heterogeneous, and the molecular basis for VSD in an overwhelming majority of patients remains unknown. In this study, the whole coding region of GATA5, a gene encoding a zinc finger transcription factor crucial for normal cardiogenesis, was sequenced in 120 unrelated patients with VSD. The available relatives of the patient harboring the identified mutation and 200 unrelated individuals used as controls were subsequently genotyped. The causative potential of a sequence variation was evaluated by MutationTaster, and the functional effect of the mutation was characterized using a luciferase reporter assay system. As a result, a novel heterozygous GATA5 mutation, p.L199V, was identified in a patient with VSD, which was absent in 400 control chromosomes. Genetic analysis of the mutation carrier’s available family members showed that the substitution co-segregated with VSD transmitted in an autosomal dominant pattern. The p.L199V variation was automatically predicted to be disease causing, and the functional analysis showed that the GATA5 p.L199V mutant protein was associated with significantly reduced transcriptional activation compared with its wild-type counterpart. To the best of the authors’ knowledge, this is the first report on the link of functionally compromised GATA5 to human VSD, suggesting potential implications for the early prophylaxis and personalized treatment of VSD.

Ventricular septal defect (VSD) is the most common form of congenital cardiovascular malformation and an important contributor to the substantially increased morbidity and mortality in infants. Emerging evidence indicates the genetic basis for the pathogenesis of congenital VSD in a significant proportion of patients. However, congenital VSD is a genetically heterogeneous disease and the genetic defects responsible for VSD in the overwhelming majority of cases remain unclear. In this study, the entire coding region of the GATA6 gene, which encodes a zinc-finger transcription factor crucial to normal cardiogenesis, was sequenced in 130 unrelated patients with congenital VSD. The available relatives of the index patient carrying the identified mutation and 200 unrelated ethnically matched healthy individuals used as controls were subsequently genotyped. The functional characteristics of the mutant GATA6 were assessed in contrast to its wild-type counterpart using a luciferase reporter assay system. As a result, a novel heterozygous missense GATA6 mutation, p.G220S, was identified in a proband with VSD. The variation was absent in 400 control chromosomes and the altered amino acid was highly conserved evolutionarily across species. Genetic analysis of the family members of the mutation carrier showed that the substitution co-segregated with VSD was inherited as an autosomal dominant trait. Functional analysis demonstrated that the p.G220S mutation of GATA6 was associated with significantly decreased transcriptional activity. The findings provide novel insight into the molecular mechanism involved in VSD, implying the potential clinical implications in the gene-specific prophylaxis and therapy of this common developmental abnormality in neonates.

Ventricular septal defect (VSD) is the most prevalent type of congenital heart disease and a major cause for the significantly increased morbidity and mortality among infants. Aggregating evidence indicates that genetic defects are involved in the pathogenesis of congenital VSD. Nevertheless, VSD is genetically heterogeneous, and the genetic determinants for VSD in the majority of patients remain to be identified. In this study, the entire coding region of GATA4, a gene encoding a zinc finger transcription factor essential for normal cardiac morphogenesis, was sequenced in 160 unrelated patients with VSD. The available relatives of the index patient harboring the identified mutation and 200 unrelated control individuals were subsequently genotyped. The disease-causing potential of a sequence alteration was evaluated by MutationTaster, and the functional effect of the mutation was characterized using a luciferase reporter assay system. As a result, a novel heterozygous GATA4 variation, p.R43W, was identified in a proband with VSD, that was absent in control subjects. Genetic analysis of the family members of the variation carrier showed that the substitution co-segregated with VSD. The p.R43W variant was predicted to be a pathogenic mutation, and the functional analysis demonstrated that the GATA4 R43W mutant protein resulted in significantly decreased transcriptional activity compared with its wild-type counterpart. The findings expand the mutational spectrum of GATA4 linked to VSD and provide more insight into the molecular mechanism of VSD.

Ventricular septal defect (VSD) is the most common type of cardiovascular developmental anomaly and is an important risk factor for the substantially increased morbidity and mortality in newborns. Aggregating evidence implicates genetic defects in the pathogenesis of congenital VSD. However, VSD is genetically heterogeneous and the genetic determinants for VSD in most patients remain to be identified. In this study, the whole coding region of the GATA4 gene, which encodes a zinc-finger transcription factor pivotal to cardiogenesis, was initially sequenced in 210 unrelated patients with VSD. The relatives of the index patient carrying the identified mutation and 200 unrelated ethnically-matched healthy individuals used as controls were subsequently genotyped. The functional effect of the mutant GATA4 was characterized in contrast to its wild-type counterpart using a luciferase reporter assay system. A novel heterozygous GATA4 mutation, p.G296R, was identified in a family with VSD inherited as an autosomal dominant trait. Absent in 200 control individuals, the mutation co-segregated with VSD in the family with 100% penetrance and was completely conserved evolutionarily across species. Functional analysis displayed that the p.G296R mutation of GATA4 was associated with a decreased transcriptional activity. The findings expand the spectrum of mutations in GATA4 linked to VSD and provide more insight into the molecular mechanism involved in VSD. The results of the present study imply the potential implications in the genetic diagnosis and gene-specific therapy of this common malformation in infancy.

Ventricular septal defect (VSD) is the most common cardiovascular malformation and an important contributor to the substantial morbidity and mortality in infancy. Growing evidence suggests that genetic defects play important roles in the pathogenesis of congenital VSD. However, VSD is of great genetic heterogeneity and the genetic basis for VSD in the majority of the patients remains largely unhnown. In this study, the entire coding region of the NKX2-5 gene, which encodes a homeodomain-containing transcription factor crucial to cardiogenesis, was initially sequenced in 136 unrelated patients with VSD. The relatives of a proband harboring the identified mutation and 200 unrelated control individuals were genotyped. The functional characteristic of the mutant transcription factor was analyzed in contrast to its wild-type counterpart using a luciferase reporter assay system. A novel heterozygous NKX2-5 mutation, p.P59A, was identified in a family with autosomal dominant inherited VSD. Absent in the 200 control individuals, the mutation was highly conserved evolutionarily and co-segregated with VSD in the family with complete penetrance. Functional analysis revealed that the p.P59A mutation of NKX2-5 was associated with a decreased transcriptional activity. These findings expand the spectrum of the mutations in NKX2-5 linked to VSD and provide new insight into the molecular mechanisms involved in VSD. The resuls of the present study may have potential implications in the genetic diagnosis and gene-specific therapy of this common childhood disease.

To identify the genetic defects in patients with congenital atrial septal defects (ASD).The clinical data and blood samples from 180 unrelated subjects with congenital ASD were collected and evaluated. Two hundred healthy individuals served as controls. The coding exons and the flanking introns of GATA4 gene were amplified by polymerase chain reaction and sequenced using the di-deoxynucleotide chain termination approach. The acquired sequences were aligned with the sequences publicized in GenBank by the aid of programme BLAST to identify the sequence variations. Clustal W software was applied for analysis of the conservation of altered amino acids.Two novel heterozygous missense GATA4 mutations were identified in 2 out of 180 ASD patients. Namely, the triplet substitutions of GTC for GGC at codon 21 and TCG for CCG at codon 87 were detected, predicting the conversions of glycine into valine at amino acid residue 21 (G21V) and proline into serine at amino acid residue 87 (P87S). None of the two mutations were detected in 200 healthy controls. Across-species alignment of GATA4 encoded protein sequences displayed that the mutated amino acids were highly conserved evolutionarily. Additionally, a single nucleotide polymorphism c.99GT was observed. However, the polymorphic frequency distribution in ASD cases was similar with that in healthy controls (for genotype GT, χ(2) = 0.7556, P = 0.3847; for allele T, χ(2) = 0.7235, P = 0.3950).Two novel mutations of GATA4 gene are identified in two unrelated ASD patients. This finding provides new insight into the molecular etiology responsible for ASD.

To identify the GATA4 gene mutation of congenital ventricular septal defect (VSD) and study the molecular mechanism of a novel mutation.The clinical data and blood samples from 185 unrelated subjects with congenital VSD were collected and evaluated together with 200 healthy individuals. The coding exons and the flanking intron regions of the GATA4 gene were amplified by PCR and sequenced using the di-deoxynucleotide chain termination approach. The GATA4 gene was cloned and the corresponding mutant was acquired by site directed mutagenesis. The recombinant plasmid expressing GATA4 and the reporter vector expressing enhanced green fluorescence protein (EGFP) driven by the promoter of atrial natrium peptide (ANP) gene were transfected into HeLa cells with Lipofectamine. The effect of mutated GATA4 gene on the transcriptional activity of encoded transcriptional factor was analyzed by reverse transcription (RT)-PCR.A novel heterozygous missense GATA4 mutation, c.191GA was identified in 1 VSD patient. The mutation leads to glycine to glutamic acid change at amino acid residue 64 (G64E) in the GATA4 protein. Functional analysis showed that GATA4 G64E mutation decreased the transcriptional activity of GATA4 transcriptional factor.A novel heterozygous missense GATA4 mutation, G64E, was identified in 1 VSD patient. The mutation might cause VSD by impairing the transcriptional activity of GATA4 transcriptional factor.

Atrial septal defect (ASD) is a common cardiovascular malformation and an important contributor to substantial morbidity and mortality. Increasing evidence demonstrates that mutated NKX2-5, a gene encoding a homeobox transcription factor crucial to cardiogenesis, is a significant genetic determinant for congenital ASD. Nevertheless, the genetic basis for ASD in a majority of ASD patients remains largely unknown. In the current study, the entire coding region of NKX2-5 was sequenced initially for 58 unrelated probands with familial ASD. The relatives of the probands harboring identified mutations and 200 unrelated control individuals were subsequently genotyped. Three novel heterozygous NKX2-5 mutations (p.P43GfsX59, p.C46 W, and p.S179F) were identified respectively in three families with autosomal dominantly inherited ASD. These mutations, absent in 200 control individuals, cosegregated with ASD in the families that had complete penetrance. The findings expand the spectrum of mutations in NKX2-5 linked to ASD and contribute to genetic counseling, clinical interventions, and prenatal prevention of ASD for individuals with genetic susceptibility.

GATA6 is a member of the GATA family of transcription factors, and its expression and functions overlap with those of GATA4 during heart development. Mutations in GATA4 have been related to human congenital heart diseases (CHDs) in several studies, whereas mutations in GATA6 have only recently been reported in patients with persistent truncus arteriosus. Animal experiments have revealed critical roles for GATA6 in the development of the myocardium and cardiac morphogenesis, thereby highlighting the potential involvement of GATA6 defects in the pathogenesis of CHDs. Here, we screened the GATA6 in 270 individuals with sporadic CHDs by direct sequencing. After identification of the mutation, a luciferase reporter assay and real-time quantitative polymerase chain reaction were performed to detect functional changes in the mutant transcription factor. The same heterozygous missense mutation (Ser184Asn) was identified in three patients, including one with tetralogy of Fallot and two with atrial septal defects. This mutation was not found in 500 unrelated ethnically matched healthy subjects. Direct sequencing of this region in the parents of these three patients revealed the same mutation in one of the parents for each patient, and one of the parent carriers presented with a bicuspid aortic valve. Biological analysis revealed clearly decreased transcriptional activity of GATA6 Ser184Asn in vitro. All these data suggest that GATA6 Ser184Asn is a novel mutation associated with CHDs and has an important role in disease pathogenesis.

The purpose of this investigation was to identify the novel genetic mutations in patients with a congenital atrial septal defect (ASD).Clinical data and blood specimens from a total of 12 unrelated ASD pedigrees and a cohort of 168 unrelated subjects with sporadic ASD were collected and evaluated in contrast to 200 healthy individuals. The whole exons and partial flanking introns of NKX2-5 gene were amplified by polymerase chain reaction and sequenced using the di-deoxynucleotide chain termination approach. The acquired sequences were aligned with those publicized in GenBank by the aid of programme BLAST to identify the sequence variations. The software ClustalW was applied for analysis of the conservative of the altered amino acids.A novel heterozygous mutation of NKX2-5 gene, i.e., a substitution of thymine for cytosine at nucleotide 536, predicting the conversion of serine into phenylalanine at amino acid residue 179, was identified initially in a proband. The same missense mutation was thereafter detected in other 3 affected members of the identical family but neither in the healthy members of the kindred nor in the 200 normal controls. A cross-species alignment of the protein sequences encoded by NKX2-5 gene displayed that the mutated amino acid was highly conserved evolutionarily. No mutation of NKX2-5 gene was observed in the other 11 ASD pedigrees or in 168 patients with sporadic ASD. Additionally, a common synonymous single nucleotide polymorphism, a transition of adenine (A) into guanine (G) at nucleotide 63, was found in NKX2-5 gene. However, there were no significant differences in the prevalence of alleles A and G between ASD patients and healthy controls (chi(2) = 2.8641, P = 0.0906).A novel mutation of NKX2-5 gene identified in an ASD family suggests that mutated NKX2-5 gene is responsible for familial ASD.