Min Da

A genome-wide association study identifies two risk loci for congenital heart malformations in Han Chinese populations

Congenital heart malformation (CHM) is the most common form of congenital human birth anomaly and is the leading cause of infant mortality. Although some causative genes have been identified, little progress has been made in identifying genes in which low-penetrance susceptibility variants occur in the majority of sporadic CHM cases. To identify common genetic variants associated with sporadic non-syndromic CHM in Han Chinese populations, we performed a multistage genome-wide association study (GWAS) in a total of 4,225 CHM cases and 5,112 non-CHM controls. The GWAS stage included 945 cases and 1,246 controls and was followed by 2-stage validation with 2,160 cases and 3,866 controls. The combined analyses identified significant associations (P < 5.0 × 10−8) at 1p12 (rs2474937 near TBX15; odds ratio (OR) = 1.40; P = 8.44 × 10−10) and 4q31.1 (rs1531070 in MAML3; OR = 1.40; P = 4.99 × 10−12). These results extend current knowledge of genetic contributions to CHM in Han Chinese populations.

Maternal lifestyle factors in pregnancy and congenital heart defects in offspring: review of the current evidence

The prognosis of children with congenital heart defects(CHDs) continues to improve with advancing surgical techniques; however, lack of information about modifiable risk factors for malformations in cardiovascular development impeded the prevention of CHDs. We investigated an association between maternal lifestyle factors and the risk of CHDs, because epidemiological studies have reported conflicting results regarding maternal lifestyle factors and the risk of CHDs recently. A review published on 2007 provided a summary of maternal exposures associated with an increased risk of CHDs. As part of noninherited risk factors, we conducted a brief overview of studies on the evidence linking common maternal lifestyle factors, specifically smoking, alcohol, illicit drugs, caffeine, body mass index and psychological factors to the development of CHDs in offspring. Women who smoke and have an excessive body mass index(BMI) during pregnancy are suspected to be associated with CHDs in offspring. Our findings could cause public health policy makers to pay more attention to women at risk and could be used in the development of population-based prevention strategies to reduce the incidence and burden of CHDs. However, more prospective studies are needed to investigate the association between maternal lifestyle factors and CHDs.

Association analysis identifies new risk loci for congenital heart disease in Chinese populations

Our previous genome-wide association study (GWAS) identified two susceptibility loci for congenital heart disease (CHD) in Han Chinese. Here we identify additional loci by testing promising associations in an extended 3-stage validation consisting of 6,053 CHD cases and 7,410 controls. We find GW significant (P<5.0 × 10(-8)) evidence of 4 additional CHD susceptibility loci at 4q31.22 (rs1400558, upstream of EDNRA, Pall=1.63 × 10(-9)), 9p24.2 (rs7863990, close to SMARCA2, Pall=3.71 × 10(-14)), 12q24.13 (rs2433752, upstream of TBX3 and TBX5, Pall=1.04 × 10(-10)) and 20q12 (rs490514, in PTPRT, Pall=1.20 × 10(-13)). Moreover, the data from previous European GWAS supports that rs490514 is associated with the risk of CHD (P=3.40 × 10(-3)). These results enhance our understanding of CHD susceptibility.

Maternal Socioeconomic Status and the Risk of Congenital Heart Defects in Offspring: A Meta-Analysis of 33 Studies

Background We conducted this meta-analysis to address the open question of a possible association between maternal socioeconomic status and congenital heart defects (CHDs). Methods We searched MEDLINE and EMBASE from their inception to January 1, 2014 for case-control and cohort studies that assessed the association between maternal socioeconomic status and the risk of CHDs. Study-specific relative risk estimates were polled according to random-effect or fixed-effect models. Results From 3343 references, a total of 31 case-control studies and 2 cohort studies were enrolled in this meta-analysis, including more than 50,000 cases. We observed that maternal educational attainment, family income and maternal occupation were negatively associated with an 11% (pooled RR = 1.11, 95% CI: 1.03, 1.21), 5% (pooled RR = 1.05, 95% CI: 1.01, 1.09) and 51% (pooled RR = 1.51, 95% CI: 1.02, 2.24) increased risk of CHDs, respectively. In a subgroup analysis by geographic region, the results were inconsistent for the European region (RR = 1.29, 95% CI: 0.99–1.69) and USA/Canada region (RR = 1.06, 95% CI: 0.97, 1.16) in maternal educational attainment. Conclusion In summary, this meta-analysis suggests that a lower degree of maternal socioeconomic status is modestly associated with an increased risk of CHDs. However, further investigations are needed to confirm the association.

Genetic variants at 10p11 confer risk of tetralogy of fallot in Chinese of Nanjing

A recent genome-wide association study (GWAS) has identified a new subset of susceptibility loci of Tetralogy of Fallot (TOF), one form of cyanotic congenital heart disease (CHD), on chromosomes 10p11, 10p14, 12q24, 13q31, 15q13 and 16q12 in Europeans. In the current study, we conducted a case-control study in a Chinese population including 1,010 CHD cases [atrial septal defect (ASD), ventricular septal defect (VSD) and TOF] and 1,962 controls to evaluate the associations of these loci with risk of CHD. We found that rs2228638 in NRP1 on 10p11 was significantly increased the risk of TOF (OR = 1.52, 95% CI = 1.13–2.04, P = 0.006), but not in other subgroups including ASD and VSD. In addition, no significant associations were observed between the other loci and the risk of ASD, VSD or TOF. Our results suggested that the genetic variants on 10p11 may serve as candidate markers for TOF susceptibility in Chinese population.

Replication of the 4p16 Susceptibility Locus in Congenital Heart Disease in Han Chinese Populations

Congenital heart disease (CHD) is the most common form of congenital human birth anomalies and a leading cause of perinatal and infant mortality. Some studies including our published genome-wide association study (GWAS) of CHD have indicated that genetic variants may contribute to the risk of CHD. Recently, Cordell et al. published a GWAS of multiple CHD phenotypes in European Caucasians and identified 3 susceptibility loci (rs870142, rs16835979 and rs6824295) for ostium secundum atrial septal defect (ASD) at chromosome 4p16. However, whether these loci at 4p16 confer the predisposition to CHD in Chinese population is unclear. In the current study, we first analyzed the associations between these 3 single nucleotide polymorphisms (SNPs) at 4p16 and CHD risk by using our existing genome-wide scan data and found all of the 3 SNPs showed significant associations with ASD in the same direction as that observed in Cordell’s study, but not with other subtypes- ventricular septal defect (VSD) and ASD combined VSD. As these 3 SNPs were in high linkage disequilibrium (LD) in Chinese population, we selected one SNP with the lowest P value in our GWAS scan (rs16835979) to perform a replication study with additional 1,709 CHD cases with multiple phenotypes and 1,962 controls. The significant association was also observed only within the ASD subgroup, which was heterogeneous from other disease groups. In combined GWAS and replication samples, the minor allele of rs16835979 remained significant association with the risk of ASD (OR = 1.22, 95% CI = 1.08–1.38, P = 0.001). Our findings suggest that susceptibility loci of ASD identified from Cordell’s European GWAS are generalizable to Chinese population, and such investigation may provide new insights into the roles of genetic variants in the etiology of different CHD phenotypes.

Maternal parity and the risk of congenital heart defects in offspring: a dose-response meta-analysis of epidemiological observational studies.

Background Epidemiological studies have reported conflicting results regarding maternal parity and the risk of congenital heart defects (CHDs). However, a meta-analysis of the association between maternal parity and CHDs in offspring has not been conducted. Methods We searched MEDLINE and EMBASE for articles catalogued between their inception and March 8, 2014; we identified relevant published studies that assessed the association between maternal parity and CHD risk. Two authors independently assessed the eligibility of the retrieved articles and extracted data from them. Study-specific relative risk estimates were pooled by random-effects or fixed-effects models. From the 11272 references, a total of 16 case-control studies and 3 cohort studies were enrolled in this meta-analysis. Results The overall relative risk of CHD in parous versus nulliparous women was 1.01 (95% CI, 0.97–1.06; Q = 32.34; P = 0.006; I2 = 53.6%). Furthermore, we observed a significant association between the highest versus lowest parity number, with an overall RR = 1.20 (95% CI, 1.10–1.31; (Q = 74.61, P<0.001, I2 = 82.6%). A dose–response analysis also indicated a positive effect of maternal parity on CHD risk, and the overall increase in relative risk per one live birth was 1.06 (95% CI, 1.02–1.09); Q = 68.09; P<0.001; I2 = 80.9%). We conducted stratified and meta-regression analyses to identify the origin of the heterogeneity among studies. A Galbraith plot was created to graphically assess the sources of heterogeneity. Conclusion In summary, this meta-analysis provided a robust estimate of the positive association between maternal parity and risk of CHD.

Association of Aminoacyl-tRNA Synthetases Gene Polymorphisms with the Risk of Congenital Heart Disease in the Chinese Han Population

Aminoacyl-tRNA synthetases (ARSs) are in charge of cellular protein synthesis and have additional domains that function in a versatile manner beyond translation. Eight core ARSs (EPRS, MRS, QRS, RRS, IRS, LRS, KRS, DRS) combined with three nonenzymatic components form a complex known as multisynthetase complex (MSC).We hypothesize that the single-nucleotide polymorphisms (SNPs) of the eight core ARS coding genes might influence the susceptibility of sporadic congenital heart disease (CHD). Thus, we conducted a case-control study of 984 CHD cases and 2953 non-CHD controls in the Chinese Han population to evaluate the associations of 16 potentially functional SNPs within the eight ARS coding genes with the risk of CHD. We observed significant associations with the risk of CHD for rs1061248 [G/A; odds ratio (OR) = 0.90, 95% confidence interval (CI) = 0.81–0.99; P = 3.81×10−2], rs2230301 [A/C; OR = 0.73, 95%CI = 0.60–0.90, P = 3.81×10−2], rs1061160 [G/A; OR = 1.18, 95%CI = 1.06–1.31; P = 3.53×10−3] and rs5030754 [G/A; OR = 1.39, 95%CI = 1.11–1.75; P = 4.47×10−3] of EPRS gene. After multiple comparisons, rs1061248 conferred no predisposition to CHD. Additionally, a combined analysis showed a significant dosage-response effect of CHD risk among individuals carrying the different number of risk alleles (P trend = 5.00×10−4). Compared with individuals with “0–2” risk allele, those carrying “3”, “4” or “5 or more” risk alleles had a 0.97-, 1.25- or 1.38-fold increased risk of CHD, respectively. These findings indicate that genetic variants of the EPRS gene may influence the individual susceptibility to CHD in the Chinese Han population.

Evaluation of regulatory genetic variants in POU5F1 and risk of congenital heart disease in Han Chinese.

OCT4 is a transcription factor of the POU family, which plays a key role in embryonic development and stem cell pluripotency. Previous studies have shown that Oct4 is required for cardiomyocyte differentiation in mice and its depletion could result in cardiac morphogenesis in embryo. However, whether the genetic variations in OCT4 coding gene, POU5F1, confer the predisposition to congenital heart disease (CHD) is unclear. This study sought to investigate the associations between low-frequency (defined here as having minor allele frequency (MAF) between 0.1%–5%) and rare (MAF below 0.1%) variants with potential function in POU5F1 and risk of CHD. We conducted association analysis in a two-stage case-control study with a total of 2,720 CHD cases and 3,331 controls in Chinese. The low-frequency variant rs3130933 was observed to be associated with a significantly increased risk of CHD [additive model: adjusted odds ratio (OR) = 2.15, adjusted P = 3.37 × 10−6]. Furthermore, luciferase activity assay showed that the variant A allele led to significantly lower expression levels as compared to the G allele. These findings indicate for the first time that low-frequency functional variant in POU5F1 may contribute to the risk of congenital heart malformations.

Identification of rare heterozygous missense mutations in FANCA in esophageal atresia patients using next-generation sequencing

Esophageal atresia and tracheoesophageal fistula (EA/TEF) are relatively common malformations in newborns, but the etiology of EA/TEF remains unknown. Fanconi anemia (FA) complementation group A (FANCA) is a key component of the FA core complex and is essential for the activation of the DNA repair pathway. The middle region (amino acids 674-1208) of FANCA is required for its interaction with FAAP20. We performed targeted sequencing of this binding region of FANCA (exons 23-36) in 40 EA/TEF patients. We also investigated the effect of the p.A958V mutation on the protein-protein interaction between FANCA and FAAP20 using an in vitro binding assay and co-immunoprecipitation. Immunolocalization analysis was performed to investigate the subcellular localization of FANCA, and tissue sections and immunohistochemistry were used to explore the expression of FANCA. We identified four rare missense variants in the FANCA binding region. FANCA mutations were significantly overrepresented in EA/TEF patients compared with 4300 control subjects from the NHLBI-ESP project (Fishers exact p = 2.17 × 10-5, odds ratio = 31.75). p.A958V, a novel de novo mutation in the FANCA gene, was identified in one patient with EA/TEF. We provide further evidence that the p.A958V mutation reduces the binding affinity of FANCA for FAAP20. Interestingly, the p.A958V mutation impaired the nuclear localization of the FANCA protein expressed in HeLa cells. We found that FANCA was more highly expressed in stratified squamous epithelium than in smooth muscle. In conclusion, mutations in the FANCA gene are associated with EA/TEF in humans.