Novel mutation of GATA4 gene in Kurdish population of Iran with nonsyndromic congenital heart septals defects.

BACKGROUND: The mutations in GATA4 gene induce inherited atrial and ventricular septation defects, which is the most frequent forms of congenital heart defects (CHDs) constituting about half of all cases. METHOD: We have performed High resolution melting (HRM) mutation scanning of GATA4 coding exons of nonsyndrome 100 patients as a case group including 39 atrial septal defects (ASD), 57 ventricular septal defects (VSD) and four patients with both above defects and 50 healthy individuals as a control group. Our samples are categorized according to their HRM graph. The genome sequencing has been done for 15 control samples and 25 samples of patients whose HRM analysis were similar to healthy subjects for each exon. The PolyPhen-2 and MUpro have been used to determine the causative possibility and structural stability prediction of GATA4 sequence variation. RESULTS: The HRM curve analysis exhibit that 21 patients and 3 normal samples have deviated curves for GATA4 coding exons. Sequencing analysis has revealed 12 nonsynonymous mutations while all of them resulted in stability structure of protein 10 of them are pathogenic and 2 of them are benign. Also we found two nucleotide deletions which one of them was novel and one new indel mutation resulting in frame shift mutation, and 4 synonymous variations or polymorphism in 6 of patients and 3 of normal individuals. Six or about 50% of these nonsynonymous mutations have not been previously reported. CONCLUSION: Our results show that there is a spectrum of GATA4 mutations resulting in septal defects.

Analysis of Copy Number Variants on Chromosome 21 in Down Syndrome-Associated Congenital Heart Defects.

One in five people with Down syndrome (DS) are born with an atrioventricular septal defect (AVSD), an incidence 2000 times higher than in the euploid population. The genetic loci that contribute to this risk are poorly understood. In this study, we tested two hypotheses: (1) individuals with DS carrying chromosome 21 copy number variants (CNVs) that interrupt exons may be protected from AVSD, because these CNVs return AVSD susceptibility loci back to disomy, and (2) individuals with DS carrying chromosome 21 genes spanned by microduplications are at greater risk for AVSD because these microduplications boost the dosage of AVSD susceptibility loci beyond a tolerable threshold. We tested 198 case individuals with DS+AVSD, and 211 control individuals with DS and a normal heart, using a custom microarray with dense probes tiled on chromosome 21 for array CGH (aCGH). We found that neither an individual chromosome 21 CNV nor any individual gene intersected by a CNV was associated with AVSD in DS. Burden analyses revealed that African American controls had more bases covered by rare deletions than did African American cases. Inversely, we found that Caucasian cases had more genes intersected by rare duplications than did Caucasian controls. We also showed that previously DS+AVSD (DS and a complete AVSD)-associated common CNVs on chromosome 21 failed to replicate. This research adds to the swell of evidence indicating that DS-associated AVSD is similarly heterogeneous, as is AVSD in the euploid population.

Twenty-five-year survival for aboriginal and caucasian children with congenital heart defects in Western Australia, 1980 to 2010.

BACKGROUND: Australian Aboriginal children have increased infant and childhood mortality compared with Caucasian children, but their mortality related to congenital heart defects (CHDs) throughout life is unknown. METHODS: We conducted a retrospective cohort study using data on 8,110 live born, singleton infants with CHDs born January 1980 to December 2010 from the Western Australian Register of Developmental Anomalies. Vital status was determined from death and medical records. Data for infants with chromosomal anomalies (except Down syndrome) were excluded. Kaplan-Meier Product-Limit estimates and 95% confidence intervals (CIs) were computed by Aboriginality. Hazard ratios (HRs) and 95% CIs were calculated from multivariable Cox-Proportional Hazard Regression models. RESULTS: Aboriginal children had lower survival than Caucasians for all CHDs combined but most notably during the neonatal period for functional single ventricle (50.0% vs. 86.1%; p = 0.015) and during the postneonatal period for tetralogy of Fallot (87.0% vs. 97.4%; p = 0.021) and atrioventricular septal defect (60.0% vs. 94.6%; p = 0.010). After adjusting for covariates except remoteness and socioeconomic status (SES), Aboriginal children with all CHDs combined (HR = 1.4; 95% CI, 1.0-1.9), with transposition of the great arteries (HR = 4.3; 95% CI, 1.0-18.9) or functional single ventricle (HR = 8.6; 95% CI, 1.3-57.9) had increased risk of mortality compared with Caucasian children. When remoteness and SES were included, the risks were not statistically significant. CONCLUSION: Long-term survival was lower for Aboriginal children with CHDs, and Aboriginal children with specific CHD phenotypes had increased risk of mortality throughout life. Increased risk may be due to SES and environmental factors. Birth Defects Research (Part A), 2016. © 2016 Wiley Periodicals, Inc. Birth Defects Research (Part A) 106:1016-1031, 2016. © 2016 Wiley Periodicals, Inc.

Genetic polymorphisms of the TYMS gene are not associated with congenital cardiac septal defects in a Han Chinese population.

BACKGROUND: Clinical research indicates that periconceptional administration of folic acid can reduce the occurrence of congenital cardiac septal defects (CCSDs). The vital roles of folate exhibits in three ways: the unique methyl donor for DNA expression regulation, the de novo biosynthesis of purine and pyrimidine for DNA construction, and the serum homocysteine removal. Thymidylate synthase (TYMS) is the solo catalysis enzyme for the de novo synthesis of dTMP, which is the essential precursor of DNA biosynthesis and repair process. To examine the role of TYMS in Congenital Cardiac Septal Defects (CCSDs) risk, we investigated whether genetic polymorphisms in the TYMS gene associated with the CCSDs in a Han Chinese population. METHOD: Polymorphisms in the noncoding region of TYMS were identified via direct sequencing in 32 unrelated individuals composed of half CCSDs and half control subjects. Nine SNPs and two insertion/deletion polymorphisms were genotyped from two independent case-control studies involving a total of 529 CCSDs patients and 876 healthy control participants. The associations were examined by both single polymorphism and haplotype tests using logistic regression. RESULT: We found that TYMS polymorphisms were not related to the altered CCSDs risk, and even to the changed risk of VSDs subgroup, when tested in both studied groups separately or in combination. In the haplotype analysis, there were no haplotypes significantly associated with risks for CCSDs either. CONCLUSION: Our results show no association between common genetic polymorphisms of the regulatory region of the TYMS gene and CCSDs in the Han Chinese population.

Functional variant in methionine synthase reductase intron-1 significantly increases the risk of congenital heart disease in the Han Chinese population.

BACKGROUND: Homocysteine is known to be an independent risk factor for congenital heart disease (CHD). Methionine synthase reductase (MTRR) is essential for the adequate remethylation of homocysteine, which is the dominant pathway for homocysteine removal during early embryonic development. METHODS AND RESULTS: Here, we report that the c.56+781 A>C (rs326119) variant of intron-1 of MTRR significantly increases the risk of CHD in the Han Chinese population. In 3 independent case-control studies involving a total of 2340 CHD patients and 2270 healthy control participants from different geographic areas, we observed that patients carrying the heterozygous AC and homozygous CC genotype had a 1.40-fold (odds ratio=1.40; P=2.32×10(-7)) and 1.84-fold (odds ratio=1.84; P=2.3×10(-11)) increased risk, respectively, of developing CHD than those carrying the wild-type AA genotype. Both in vivo quantitative real-time polymerase chain reaction analysis of MTRR mRNA in cardiac tissue samples from CHD patients and in vitro luciferase assays in transfected cells demonstrated that the c.56+781 C allele profoundly decreased MTRR transcription. Further analysis demonstrated that the c.56+781 C allele manifested reduced CCAAT/enhancer binding protein-α binding affinity. In addition, healthy individuals with the homozygous CC genotype had significantly elevated levels of plasma homocysteine compared with the wild-type AA carriers. CONCLUSIONS: We have demonstrated that the MTRR c.56+781 A>C variant is an important genetic marker for increased CHD risk because this variant results in functionally reduced MTRR expression at the transcriptional level. Our results accentuate the significance of functional single-nucleotide polymorphisms in noncoding regions of the homocysteine/folate metabolism pathway core genes for their potential contributions to the origin of CHD.

[Association between GATA-4 mutations and congenital cardiac septal defects in Han Chinese patients].

OBJECTIVE: To elucidate the association between GATA-4 gene mutations and congenital cardiac septal defects in Han Chinese patients. METHODS: Fifty Han Chinese patients with congenital cardiac septal defects and 100 normal subjects with the same ethnical background were studied. Total six exons and the intron-exon boundaries of GATA-4 were amplified by the polymerase chain reaction. The polymerase chain reaction products were purified and directly sequenced with automatic sequencer. RESULTS: Two novel heterozygous mutations were discovered in the GATA-4 gene of patients with congenital cardiac septal defects, His28Tyr in exon 2 and His436Tyr in exon 7 respectively, which were absent in the control population and not reported in the SNP database (http://www.ncbi.nlm.nih.gov/SNP). CONCLUSION: Our finding suggests that the mutations in the transcription factor GATA-4 may be related to congenital cardiac septal defects in Han Chinese patients.

Right-to-left shunts may be not uncommon cause of TIA in Japan.

BACKGROUND AND PURPOSE: Although 30% to 60% of transient ischemic attacks (TIAs) have embolic sources, the etiology of the remaining TIAs is unknown. Right-to-left shunt (RLS) is one of the most important etiologies of cryptogenic stroke. The aim of this study was to determine whether RLS is related to transient ischemic attack (TIA) of unknown etiology. METHODS: We performed transesophageal echocardiography (TEE) and/or transcranial Doppler (TCD) studies for consecutive TIA patients in order to detect RLS from April 2004 to December 2006. TIA patients were divided into three groups, as follows: 1) Cardioembolic TIA, with a patent cardioembolic source, 2) thrombotic TIA, with an atherothrombotic and/or lacunar mechanism, and 3) undetermined TIA, without identified cause of TIA. We compared the characteristics and presence of RLS among these three groups. RESULTS: We enrolled 124 TIA patients (age: 67+/-13 years old, 80 men). There were 13 patients with Cardioembolic TIA, 25 with Thrombotic TIA, and 86 with Undetermined TIA. TEE and/or TCD were able to detect RLS in 61 of the 124 (49%) patients. RLS was frequent in patients with Undetermined TIA compared with those in the other TIA groups (60% in the Undetermined TIA group, 28% in the Thrombotic TIA group, and 15% in the Cardioembolic TIA group; p<0.001). Smoking and previous history of TIA were frequent in the Thrombotic TIA group (p=0.030 and p=0.016, respectively). CONCLUSION: RLS may play an important role in the etiology of TIA of undetermined cause.