Pengyun Wang

Functional dominant-negative mutation of sodium channel subunit gene SCN3B associated with atrial fibrillation in a Chinese GeneID population

Atrial fibrillation (AF) is the most common cardiac arrhythmia in the clinic, and accounts for more than 15% of strokes. Mutations in cardiac sodium channel alpha, beta1 and beta2 subunit genes (SCN5A, SCN1B, and SCN2B) have been identified in AF patients. We hypothesize that mutations in the sodium channel beta3 subunit gene SCN3B are also associated with AF. To test this hypothesis, we carried out a large scale sequencing analysis of all coding exons and exon-intron boundaries of SCN3B in 477 AF patients (28.5% lone AF) from the GeneID Chinese Han population. A novel A130V mutation was identified in a 46-year-old patient with lone AF, and the mutation was absent in 500 controls. Mutation A130V dramatically decreased the cardiac sodium current density when expressed in HEK293/Na(v)1.5 stable cell line, but did not have significant effect on kinetics of activation, inactivation, and channel recovery from inactivation. When co-expressed with wild type SCN3B, the A130V mutant SCN3B negated the function of wild type SCN3B, suggesting that A130V acts by a dominant negative mechanism. Western blot analysis with biotinylated plasma membrane protein extracts revealed that A130V did not affect cell surface expression of Na(v)1.5 or SCN3B, suggesting that mutant A130V SCN3B may not inhibit sodium channel trafficking, instead may affect conduction of sodium ions due to its malfunction as an integral component of the channel complex. This study identifies the first AF-associated mutation in SCN3B, and suggests that mutations in SCN3B may be a new pathogenic cause of AF.

The Same Chromosome 9p21.3 Locus Is Associated With Type 2 Diabetes and Coronary Artery Disease in a Chinese Han Population

OBJECTIVE Recent genome-wide association studies (GWAS) revealed that a 9p21.3 locus was associated with type 2 diabetes. In this study, we carried out a large-scale case-control study in the GeneID Chinese Han population to 1) further replicate the association of 9p21.3 type 2 diabetes GWAS single nucleotide polymorphisms (SNPs) and 2) assess the association of these SNPs with coronary artery disease. RESEARCH DESIGN AND METHODS Three SNPs (rs2383208, rs10811661, and rs10757283) were genotyped in two GeneID cohorts of 3,167 Chinese Han individuals. Case-control association design was used to determine the association of the SNPs with type 2 diabetes and coronary artery disease. Gensini scores were calculated in the coronary artery disease subjects and were tested for association with the variants. Multivariate logistic regressions were performed on association studies. RESULTS The association between two of the three SNPs and type 2 diabetes was replicated in the GeneID population (rs2383208, P = 0.936; rs10811661-T, P = 0.02, odds ratio [OR] = 1.23; rs10757283-C, P = 0.003, OR = 1.30). The same two SNPs also contributed to the risk of coronary artery disease (CAD) (rs10811661-T, P = 0.002, OR = 1.19; rs10757283-C, P = 0.003, OR = 1.18). In addition, rs10757283 was associated with severity of coronary atherosclerosis estimated by the Gensini scoring system (risk allele C, quantitative-trait regression adjusted P = 0.002). CONCLUSIONS For the first time to our knowledge, our results indicated that the same 9p21.3 locus, represented by SNPs rs10811661 and rs10757283, contributed to the risk of type 2 diabetes and coronary artery disease in our GeneID Chinese Han population.

Minor Allele C of Chromosome 1p32 Single Nucleotide Polymorphism rs11206510 Confers Risk of Ischemic Stroke in the Chinese Han Population

Background and Purpose— Genome-wide association studies found that the common allele T of single nucleotide polymorphism rs11206510 on chromosome 1p32 was associated with increased low-density lipoprotein-cholesterol levels (LDL-C) and with risk of coronary artery disease (CAD) in white populations. The goals of this study are to determine whether rs11206510 is associated with LDL-C and CAD in a different ethnic population, namely a Chinese cohort, and to investigate whether rs11206510 is associated with ischemic stroke. Methods— The association of rs11206510 with LDL-C was analyzed in 1415 Chinese Han subjects. The CAD study utilized a GeneID cohort with 1543 CAD patients and 1240 controls. For stroke studies, 2 independent cohorts were used and included the GeneID North cohort, with 1205 cases and 1205 controls, and the GeneID Central cohort, with 692 cases and 882 controls. Results— Different from white populations, the minor allele C of rs11206510 was associated with increased LDL-C levels in the Chinese Han population (adjusted P=0.002) and conferred risk of early-onset CAD (380 cases vs 1240 controls; adjusted P=0.002, odds ratio, 1.89), but not with overall CAD (adjusted P=0.82). The allelic association with ischemic stroke was highly significant in 2 independent cohorts, with adjusted P=1.13×10−5 (odds ratio,1.71) in the GeneID North cohort and adjusted P=9.32×10−5 (odds ratio, 1.70) in the GeneID Central cohort. Genotypic association was also significant for both early-onset CAD and ischemic stroke. Conclusions— Our results indicate that single nucleotide polymorphism rs11206510 is associated with LDL-C levels and early-onset CAD in the Chinese Han population. For the first time to our knowledge, this study also demonstrates that rs11206510 confers a significant risk of ischemic stroke.

T14484C and T14502C in the mitochondrial ND6 gene are associated with Leber's hereditary optic neuropathy in a Chinese family

Lebers hereditary optic neuropathy (LHON) is a maternally inherited ocular disease which has been associated with three primary mitochondrial DNA mutations: G3640A, G11778A, and T14484C. In this study, we clinically characterized a Chinese family with complete penetrance of LHON. The patients in the family presented with variable clinical features. By direct DNA sequence analysis, we identified both T14484C mutation and a nearby T to C variant at nucleotide 14502 of mitochondria DNA. The T14502C variant altered I58 to V of the protein ND6, which was present in all patients of the family, but not in four unaffected family members and 200 normal controls. The co-existence of both T14484C mutation and T14502C substitution in all patients from the same LHON family suggests that T14502C may play a synergistic role with the primary mutation T14484C. The two variants together may account for the complete penetrance and absence of marked gender bias and visual recovery in the Chinese LHON family although we cannot exclude the possibility of simultaneous involvement of additional mitochondrial variant(s).

Identification of a novel KCNQ1 mutation associated with both Jervell and Lange-Nielsen and Romano-Ward forms of long QT syndrome in a Chinese family

BackgroundLong QT syndrome (LQTS) is a cardiac disorder characterized by prolonged QT intervals on electrocardiograms (ECG), ventricular arrhythmias, and sudden death. Clinically, two inherited forms of LQTS have been defined: autosomal dominant LQTS or Romano-Ward syndrome (RWS) not associated with deafness and autosomal recessive LQTS or Jervell and Lange-Nielsen syndrome (JLNS) associated with deafness.MethodsA Chinese family with both RWS and JLNS was identified. Family members were diagnosed based on the presence of a prolonged QT interval as seen on a 12-lead ECG and a medical history of syncope, palpitation, and deafness. Mutational studies in the KCNQ1 potassium channel gene were performed using direct DNA sequence analysis and restriction length polymorphism analysis.ResultsThe proband in the Chinese family and her brother had previously been diagnosed with JLNS, and two other members were affected with RWS. The proband was also affected with atrial fibrillation. A single nucleotide substitution of C to T at nucleotide 965 of KCNQ1 was identified, and the mutation resulted in the substitution of a threonine residue at codon 322 by a methionine residue (T322M). The novel heterozygous T322M mutation was identified in two patients with RWS, one member with borderline QTc, and two normal family members. The two JLNS patients in the family carried the homozygous T322M mutation. The T322M mutation was not found in 200 Chinese normal controls.ConclusionOur results suggest that T322M is a novel mutation that caused RWS with high intrafamilial variability in the heterozygous carriers and typical JLNS in the homozygous carriers within this Chinese family. The T322M mutation is the first mutation identified for JLNS in the Chinese population.

Candidate Pathway-Based Genome-Wide Association Studies Identify Novel Associations of Genomic Variants in the Complement System Associated With Coronary Artery Disease

Background—Genomic variants identified by genome-wide association studies (GWAS) explain <20% of heritability of coronary artery disease (CAD), thus many risk variants remain missing for CAD. Identification of new variants may unravel new biological pathways and genetic mechanisms for CAD. To identify new variants associated with CAD, we developed a candidate pathway-based GWAS by integrating expression quantitative loci analysis and mining of GWAS data with variants in a candidate pathway. Methods and Results—Mining of GWAS data was performed to analyze variants in 32 complement system genes for positive association with CAD. Functional variants in genes showing positive association were then identified by searching existing expression quantitative loci databases and validated by real-time reverse transcription polymerase chain reaction. A follow-up case–control design was then used to determine whether the functional variants are associated with CAD in 2 independent GeneID Chinese populations. Candidate pathway-based GWAS identified positive association between variants in C3AR1 and C6 and CAD. Two functional variants, rs7842 in C3AR1 and rs4400166 in C6, were found to be associated with expression levels of C3AR1 and C6, respectively. Significant association was identified between rs7842 and CAD (P=3.99×10−6; odds ratio, 1.47) and between rs4400166 and CAD (P=9.30×10−3; odds ratio, 1.24) in the validation cohort. The significant findings were confirmed in the replication cohort (P=1.53×10−5; odds ratio, 1.37 for rs7842; P=8.41×10−3; odds ratio, 1.21 for rs4400166). Conclusions—Integration of GWAS with biological pathways and expression quantitative loci is effective in identifying new risk variants for CAD. Functional variants increasing C3AR1 and C6 expression were shown to confer significant risk of CAD for the first time.

Association of SNP Rs9943582 in APLNR with Left Ventricle Systolic Dysfunction in Patients with Coronary Artery Disease in a Chinese Han GeneID Population.

Heart failure affects 1–2% of the adult population worldwide and coronary artery disease (CAD) is the underlying etiology of heart failure in 70% of the patients. The pathway of apelin and its apelin receptor (APJ) was implicated in the pathogenesis of heart failure in animal models, but a similar role in humans is unknown. We studied a functional variant, rs9943582 (-154G/A), at the 5’-untranslated region, that was associated with decreased expression of the APJ receptor gene (APLNR) in a population consisting of 1,751 CAD cases and 1,022 controls. Variant rs9943582 was not associated with CAD, but among CAD patients, it showed significant association with left ventricular systolic dysfunction (431 CAD patients with left ventricular systolic dysfunction (LV ejection fraction or LVEF< 40%) versus 1,046 CAD patients without LV systolic dysfunction (LVEF>50%) (P-adj = 6.71×10-5, OR = 1.43, 95% CI, 1.20–1.70). Moreover, rs9943582 also showed significant association with quantitative echocardiographic parameters, including left ventricular end-diastolic diameter (effect size: increased 1.67±0.43 mm per risk allele A, P = 1.15×10-4), left atrial size (effect size: increased 2.12±0.61 mm per risk allele A, P = 9.56×10-4) and LVEF (effect size: decreased 2.59±0.32 percent per risk allele A, P = 7.50×10-15). Our findings demonstrate that allele A of rs9943582 was significantly associated with left ventricular systolic dysfunction, left ventricular end-diastolic diameter, the left atrial diameter and LVEF in the CAD population, which suggests an important role of the apelin/APJ system in the pathology of heart failure associated with ischemic heart disease.

Analysis of the genetic association between IL27 variants and coronary artery disease in a Chinese Han population.

Interleukin-27 (IL-27) is an important cytokine in inflammatory diseases, including coronary artery disease (CAD). To explore the precise role of IL-27 in CAD, we investigated the genetic association between IL27 and CAD in the GeneID Chinese Han population. A two-stage case control association analysis was performed for 3075 CAD cases and 2802 controls. Logistic regression analysis was used to adjust the traditional risk factors for CAD. Results showed that a promoter variant, rs153109, tended to be marginally associated with CAD in the discovery population (Padj = 0.028, OR = 1.27, 95%CI: 1.03–1.58). However, this association was not replicated in the validation stage (Padj = 0.559, OR = 1.04, 95%CI: 0.90–1.21). In addition, when we classified the combined population into two subgroups according to the age at disease onset or disease state, we again obtained no significant associations. Finally, we estimated the severity of coronary stenosis using the Gensini Scoring system and determined that the rs153109 genotypes were still not associated with the Gensini scores of the CAD patients. In conclusion, our study failed to find an association between common variants in the functional region of IL27 and CAD in a Chinese Han population, which indicated that IL-27 might only be an inflammatory marker during the development of CAD.

Candidate Pathway-Based GWAS Identifies Novel Associations of Genomic Variants in the Complement System Associated with Coronary Artery Disease

Background—Genomic variants identified by genome-wide association studies (GWAS) explain <20% of heritability of coronary artery disease (CAD), thus many risk variants remain missing for CAD. Identification of new variants may unravel new biological pathways and genetic mechanisms for CAD. To identify new variants associated with CAD, we developed a candidate pathway-based GWAS by integrating expression quantitative loci analysis and mining of GWAS data with variants in a candidate pathway. Methods and Results—Mining of GWAS data was performed to analyze variants in 32 complement system genes for positive association with CAD. Functional variants in genes showing positive association were then identified by searching existing expression quantitative loci databases and validated by real-time reverse transcription polymerase chain reaction. A follow-up case–control design was then used to determine whether the functional variants are associated with CAD in 2 independent GeneID Chinese populations. Candidate pathway-based GWAS identified positive association between variants in C3AR1 and C6 and CAD. Two functional variants, rs7842 in C3AR1 and rs4400166 in C6, were found to be associated with expression levels of C3AR1 and C6, respectively. Significant association was identified between rs7842 and CAD (P=3.99×10−6; odds ratio, 1.47) and between rs4400166 and CAD (P=9.30×10−3; odds ratio, 1.24) in the validation cohort. The significant findings were confirmed in the replication cohort (P=1.53×10−5; odds ratio, 1.37 for rs7842; P=8.41×10−3; odds ratio, 1.21 for rs4400166). Conclusions—Integration of GWAS with biological pathways and expression quantitative loci is effective in identifying new risk variants for CAD. Functional variants increasing C3AR1 and C6 expression were shown to confer significant risk of CAD for the first time.

Genomic Variants in NEURL, GJA1 and CUX2 Significantly Increase Genetic Susceptibility to Atrial Fibrillation.

Atrial fibrillation (AF) is the most common arrhythmia. In 2014, two new meta-GWAS identified 5 AF loci, including the NEURL locus, GJA1 locus, CAND2 locus, and TBX5 locus in the European ancestry populations and the NEURL locus and CUX2 locus in a Japanese population. The TBX5 locus for AF was reported by us in 2013 in the Chinese population. Here we assessed the association between AF and SNPs in the NEURL, GJA1, CAND2 and CUX2 loci in the Chinese Han population. We carried out a large case-control association study with 1,164 AF patients and 1,460 controls. Significant allelic and genotypic associations were identified between NEURL variant rs6584555 and GJA1 variant rs13216675 and AF. Significant genotypic association was found between CUX2 SNP rs6490029 and AF. No association was found between CAND2 variant rs4642101 and AF, which may be due to an insufficient power of the sample size for rs4642101. Together with our previous findings, seven of fifteen AF loci (<50%) identified by GWAS in the European ancestry populations conferred susceptibility to AF in the Chinese population, and explained approximately 14.5% of AF heritability. On the other hand, two AF loci identified in the Japanese population were both replicated in the Chinese population.