Association of SNP rs17465637 on chromosome 1q41 and rs599839 on 1p13.3 with myocardial infarction in an American caucasian population

Association study between polymorphisms in MIA3, SELE, SMAD3 and CETP genes and coronary artery disease in an Iranian population

Background

Coronary artery disease (CAD) is the most common heart disease. Several studies have shown association between some polymorphism in different genes with CAD. Finding this association can be used in order to early diagnosis and prevention of CAD.

Method

101 CAD patients with ≥ 50% luminal stenosis of any coronary vessel as case group and 111 healthy individuals as control group were selected. the polymorphisms were evaluated by ARMS-PCR and RFLP-PCR methods.

Result

The results of this study show that there is no significant association between rs17228212, rs17465637, and rs708272 and risk of CAD. But there is significant association between risk of CAD and rs5355 (p-value = 0.022) and rs3917406 (p-value = 0.006) in total cases, and rs5882 (p-value = 0.001) in male cases.

Conclusions

Our findings revealed a significant interaction between CETP SNPs and CETP activity for affecting HDL-C levels. The SELE gene is a known cell adhesion molecule with a significant role in inflammation. Studies about possible linkage between SELE gene polymorphisms and the development of CAD are conflicting. We have found a significant association between polymorphisms of SELE gene and risk of CAD.

Sortilin as a Biomarker for Cardiovascular Disease Revisited

Genetic variants in the genomic region containing SORT1 (encoding the protein sortilin) are strongly associated with cholesterol levels and the risk of coronary artery disease (CAD). Circulating sortilin has therefore been proposed as a potential biomarker for cardiovascular disease. Multiple studies have reported association between plasma sortilin levels and cardiovascular outcomes. However, the findings are not consistent across studies, and most studies have small sample sizes. The aim of this study was to evaluate sortilin as a biomarker for CAD in a well-characterized cohort with symptoms suggestive of CAD. In total, we enrolled 1,173 patients with suspected stable CAD referred to coronary computed tomography angiography. Sortilin was measured in plasma using two different technologies for quantifying circulating sortilin: a custom-made enzyme-linked immunosorbent assay (ELISA) and OLINK Cardiovascular Panel II. We found a relative poor correlation between the two methods (correlation coefficient = 0.21). In addition, genotyping and whole-genome sequencing were performed on all patients. By whole-genome regression analysis of sortilin levels measured with ELISA and OLINK, two independent cis protein quantitative trait loci (pQTL) on chromosome 1p13.3 were identified, with one of them being a well-established risk locus for CAD. Incorporating rare genetic variants from whole-genome sequence data did not identify any additional pQTLs for plasma sortilin. None of the traditional CAD risk factors, such as sex, age, smoking, and statin use, were associated with plasma sortilin levels. Furthermore, there was no association between circulating sortilin levels and coronary artery calcium score (CACS) or disease severity. Sortilin did not improve discrimination of obstructive CAD, when added to a clinical pretest probability (PTP) model for CAD. Overall, our results indicate that studies using different methodologies for measuring circulating sortilin should be compared with caution. In conclusion, the well-known SORT1 risk locus for CAD is linked to lower sortilin levels in circulation, measured with ELISA; however, the effect sizes are too small for sortilin to be a useful biomarker for CAD in a clinical setting of low- to intermediate-risk chest-pain patients.

Low HDL concentration in rs2048327-G carriers can predispose men to develop coronary heart disease: Tehran Cardiometabolic genetic study (TCGS)

Recent genome-wide association studies (GWAS) highlighted the importance of genetic variations on SLC22A3 and MIA3 genes in developing coronary heart disease (CHD) among different ethnicities. However, the influence of these variations is not recognized within the Iranian population. Hence, in the present study, we aim to investigate two key single nucleotide polymorphisms (SNPs) on CHD incidence in this population. For this purpose, from Tehran Cardiometabolic Genetic Study (TCGS), 453 individuals with CHD were selected as a case and 453 individuals as a control that matched their age and gender. After quality control of two selected SNPs, rs2048327 (SLC22A3) and rs17465637 (MIA3), we used genotyps resulted from chip-typing technology and conducted the logistic regression analysis adjusted for non-genetic risk factors to detect the possible association of these SNPs with the CHD development. Our findings demonstrated the rs2048327-G and rs17465637-C can significantly increase the risk of CHD development about two times in only males and females, respectively. Interestingly, in the male carriers of the risk allele (G) of rs2048327, the low high-density lipoprotein (HDL) level can significantly predispose them to develop coronary heart disease in the future. According to our results, paying more attention to gender and genetic markers can help more efficient coronary heart disease screening and diagnosis.

MIA SH3 Domain ER Export Factor 3 Deficiency Prevents Neointimal Formation by Restoring BAT-Like PVAT and Decreasing VSMC Proliferation and Migration

Abnormal proliferation and migration of vascular smooth muscle cells (VSMCs) and excessive accumulation of dysfunctional PVAT are hallmarks of pathogenesis after angioplasty. Recent genome-wide association studies reveal that single-nucleotide polymorphism (SNP) in MIA3 is associated with atherosclerosis-relevant VSMC phenotypes. However, the role of MIA3 in the vascular remodeling response to injury remains unknown. Here, we found that expression of MIA3 is increased in proliferative VSMCs and knockdown of MIA3 reduces VSMCs proliferation, migration, and inflammation, whereas MIA3 overexpression promoted VSMC migration and proliferation. Moreover, knockdown of MIA3 ameliorates femoral artery wire injury-induced neointimal hyperplasia and increases brown-like perivascular adipocytes. Collectively, the data suggest that MIA3 deficiency prevents neointimal formation by decreasing VSMC proliferation, migration, and inflammation and maintaining BAT-like perivascular adipocytes in PVAT during injury-induced vascular remodeling, which provide a potential therapeutic target for preventing neointimal hyperplasia in proliferative vascular diseases.

Statistical and Functional Studies Identify Epistasis of Cardiovascular Risk Genomic Variants From Genome-Wide Association Studies

Background

Epistasis describes how gene‐gene interactions affect phenotypes, and could have a profound impact on human diseases such as coronary artery disease (CAD). The goal of this study was to identify gene‐gene interactions in CAD using an easily generalizable multi‐stage approach.

Methods and Results

Our forward genetic approach consists of multiple steps that combine statistical and functional approaches, and analyze information from global gene expression profiling, functional interactions, and genetic interactions to robustly identify gene‐gene interactions. Global gene expression profiling shows that knockdown of ANRIL (DQ485454) at 9p21.3 GWAS (genome‐wide association studies) CAD locus upregulates TMEM100 and TMEM106B. Functional studies indicate that the increased monocyte adhesion to endothelial cells and transendothelial migration of monocytes, 2 critical processes in the initiation of CAD, by ANRIL knockdown are reversed by knockdown of TMEM106B, but not of TMEM100. Furthermore, the decreased monocyte adhesion to endothelial cells and transendothelial migration of monocytes induced by ANRIL overexpression was reversed by overexpressing TMEM106B. TMEM106B expression was upregulated by >2‐fold in CAD coronary arteries. A significant association was found between variants in TMEM106B (but not in TMEM100) and CAD (P=1.9×10⁻⁸). Significant gene‐gene interaction was detected between ANRIL variant rs2383207 and TMEM106B variant rs3807865 (P=0.009). A similar approach also identifies significant interaction between rs6903956 in ADTRP and rs17465637 in MIA3 (P=0.005).

Conclusions

We demonstrate 2 pairs of epistatic interactions between GWAS loci for CAD and offer important insights into the genetic architecture and molecular mechanisms for the pathogenesis of CAD. Our strategy has broad applicability to the identification of epistasis in other human diseases.

The Mediterranean diet reduces the genetic risk of chromosome 9p21 for myocardial infarction in an Asian population community cohort

The interaction of genetic susceptibility and dietary habits in cardiovascular disease (CVD) remains undetermined. The purpose of this study was to investigate whether a Mediterranean dietary style modified the genetic risk of developing CVD in a Chinese cohort. A total of 2098 subjects with dietary information from a Chinese community cohort (CVDFACTS) were enrolled. Candidate genes, including SNP markers rs1333049 (CDKN2B, 9p21.3), rs17465637 (MIA3, 1q41) and rs501120 (CXCL12, 10q11.21), were genotyped to analyze the association with future CVD. The impact of dietary pattern was also analyzed according to adherence to the diet using the Mediterranean Diet Score (MDS). After an average follow-up of 7.8 years, only the C risk allele of rs1333049 at chromosome 9p21.3 was associated with a higher risk of MI with either an additive [HR = 1.78, 95% CI:1.23-2.5] or a recessive model [HR = 2.40, 95% CI: 1.42-4.04], and the CC genotype had a higher risk of developing MI (p = 0.009, log-rank test). There was no significant difference in the association of the lipid profile with future CV outcomes among the MDS tertiles. However, the high MI risk of the CC genotype in individuals consuming a less healthy diet (MDS1) (HR: 6.39, 95% CI: 1.74-23.43) significantly decreased to 2.38 (95% CI: 0.57-10.04) in individuals consuming a healthier diet (MDS3), indicating that a healthier dietary pattern (higher MDS) modified the risk of developing MI in carriers of variants in CDKN2B. In conclusion, genetic variants of CDKN2B at 9p21 were significantly associated with future MI risk in a Chinese cohort, and the genetic risk of MI could be modified by a healthier diet.

Complicated trafficking behaviors involved in paradoxical regulation of sortilin in lipid metabolism

This review aims to summarize and discuss the most recent advances in our understanding of the underlying mechanisms of the paradoxical effects of sortilin on lipid metabolism. The vacuolar protein sorting 10 protein (Vps10p) domain in the sortilin protein is responsible for substrate binding. Its cytoplasmic tail interacts with adaptor molecules, and modifications can determine whether sortilin trafficking occurs via the anterograde or retrograde pathway. The complicated trafficking behaviors likely contribute to the paradoxical roles of sortilin in lipid metabolism. The anterograde pathway of sortilin trafficking in hepatocytes, enterocytes, and peripheral cells likely causes an increase in plasma lipid levels, while the retrograde pathway leads to the opposite effect. Hepatocyte sortilin functions via the anterograde or retrograde pathway in a complicated and paradoxical manner to regulate apoB-containing lipoprotein metabolism. Clarifying the regulatory mechanisms underlying the trafficking behaviors of sortilin is necessary and may lead to artificial sortilin intervention as a potential therapeutic strategy for lipid disorder diseases. Conclusively, the paradoxical regulation of sortilin in lipid metabolism is likely due to its complicated trafficking behaviors.

There is an association between a genetic polymorphism in the ZNF259 gene involved in lipid metabolism and coronary artery disease

BACKGROUND

Recent genome-wide association studies (GWAS) have identified several genetic variants that influence the risk of dyslipidemia and coronary artery disease (CAD). In this study, we have examined the potential association of five SNPs variants related to lipid pathway, previously identified in GWAS studies (ZNF259 C>G, CETP I405VA/G, LPA C>T, LPLS447X and PSRC1 A>G) with CAD.

METHODS

Two hundred and ninety subjects including 194 patients with coronary artery disease and 96 controls were enrolled, followed by the analyses of anthropometric/biochemical parameters. Genotyping was carried out using Taq-Man real-time PCR based method. The association of the genetic polymorphisms with CAD was determined using univariate and multivariate analyses.

RESULTS

CAD patients had a higher (p < 0.05) fasting blood glucose (FBG), total cholesterol (TC), high sensitivity C-reactive protein (hs-CRP), low-density lipoprotein cholesterol (LDL-C) and waist circumference. Results showed that subjects with CETP rs5882 genetic variant, AA&AG genotypes, had a higher risk of developing Coronary artery disease [OR: 2.1, 95% CI (1.2-4.1), p value = 0.015]. Also subjects who carried the G allele of the ZNF259 polymorphism were at an increased the risk of developing CAD [OR 1.86, 95% CI: 1.06-3.25, p value = 0.029] and had an increased TC, LDL and TG levels (p < 0.05). Furthermore, no statistically significant association was found between genetic polymorphisms of PSRC1 A>G, LPL S447X and LPA C>T and CAD.

CONCLUSION

We identified a relationship between a genetic variant in CETP and ZNF259 gene with CAD and CAD and lipid profile, respectively. Further investigation in a larger population may help to investigate the value of emerging marker as a risk stratification marker in CAD and its risk factors.

Association of genetic polymorphisms in the pore domains of mechano-gated TREK-1 channel with overactive lower urinary tract symptoms in humans

AIMS

Mechanosensitivity of the urinary bladder is regulated by many factors including mechano-gated two-pore domain (K₂ P, KCNK) potassium channels. TWIK-related K⁺ channel, TREK-1, is a predominantly expressed member of K₂ P channel family in the human detrusor, and its expression and function are diminished in patients with overactive lower urinary tract symptoms (LUTS). The changes in channel activity may result from spontaneously occurring gene mutations. The aim of this study was to compare single nucleotide polymorphisms (SNPs) in TREK-1 channel between patients with LUTS and healthy donors.

METHODS

Six SNPs (rs370266806, rs373919966, rs758937019, rs769301539, rs772497750, and rs775158737) in two pore domains of human TREK-1 gene were analyzed using TaqMan SNP genotyping assay with manufacturer-designed primers and allele-specific probes. The screening was done in control bladders and detrusor specimens from patients with overactive LUTS. Statistical analyses were performed using R, Fisher's exact test and Hardy-Weinberg Equilibrium.

RESULTS

Six SNPs in two pore domains of the human TREK-1 gene were analyzed in human bladder specimens. The frequencies of rs758937019-CT genotype (P = 0.0016) and rs758937019-T allele (P = 0.0022) were significantly higher in the group with overactive LUTS. There was no significant association of rs775158737-GA genotype and rs775158737-A allele with the overactive LUTS, though they were present only in the overactive LUTS group.

CONCLUSIONS

Our results provide evidence that altered expression and function of TREK-1 channel in patients with overactive LUTS could be due to genetic polymorphisms in the pore domains of TREK-1 channel (rs758937019).

Analysis of causal effect of APOA5 variants on premature coronary artery disease

Apolipoprotein A5 (APOA5) regulates the metabolisms of triglyceride and HDL. APOA5 variants have been linked to coronary artery disease (CAD), but their causal roles are not well studied yet. This study aims to identify the causal effects of APOA5 variants on premature CAD. Sequencing analysis of APOA5 in 128 premature, familiar CAD patients from GeneQuest identified 11 genomic variants, including p.S19W (rs3135506). SKAT analysis showed that all sequenced variants, in aggregate, significantly increased the risk of premature CAD (P-skat = 0.037). Individually, the p.S19W variant was significantly associated with risk of premature CAD (OR = 2.30, P = 0.008) in an independent set of 342 premature CAD patients and 537 controls after adjusting for covariates of sex, age, hypertension, body mass index, triglycerides (TGs), and total, LDL-, and HDL-cholesterol levels. Meanwhile, p.S19W significantly correlated with HDL-C levels (P = 0.048) and TG levels (P = 0.025). Mediation analysis yielded a mediation effect of p.S19W on risk of premature CAD through HDL-C (OR = 0.98, P = 0.040) and TG (OR = 0.98, P = 0.042), suggesting a causal relationship between p.S19W and premature CAD partially through its effects on HDL-C and TG levels. These results suggest that APOA5 variation regulates TG and HDL levels, thus displaying a causal role in the development of CAD.

Multivariate analysis for coronary heart disease in heterozygote familial hypercholesterolemia patients

AIM

rs599839 polymorphism has been related with low levels of cholesterol and reduced coronary heart disease (CHD).

METHODS

We investigated the frequency of this polymorphism in patients with heterozygous familial hypercholesterolemia (HeFH) in the Spanish familial hypercholesterolemia cohort, 230 with and 202 without CHD. Results & discussion: A lower G-allele prevalence was observed in HeFH patients with CHD with respect to controls, 35 versus 45%, respectively (p = 0.029), suggesting a protective effect. However, it was found that there was no association between rs599839 alleles and CHD in the multivariate analysis.

CONCLUSION

The frequency of the protective G-allele of the rs599839 polymorphism was lower in HeFH patients with CHD compared with those HeFH patients without CHD. However, its role in HeFH may be masked by very high levels of cholesterol.

GWAS implicated risk variants in different genes contribute additively to increase the risk of coronary artery disease (CAD) in the Pakistani subjects

Background

Coronary artery disease (CAD) remains the single most important cause of mortality worldwide. Many candidate and GWAS genetic variants have been identified in the recent years. In the current study, we selected six SNPs from various genes that have originally been identified in GWAS studies and examined the association of SNPs individually and as a genetic risk score (GRS) with CAD and blood lipid levels in the Pakistani subjects.

Methods

Six hundred twenty-four (404 cases and 219 controls) subjects were genotyped for variants rs10757274 in CDKN2A gene, rs17465637 in MIA3 gene, rs7025486 in DAB2IP gene, rs17228212 in SMAD3 gene, rs981887 in MRAS gene and rs1746048 in CXCL12 gene, by TaqMan and KASPar allele discrimination techniques. Serum lipid parameters were measured using commercially available kits. Statistical analyses were done using SPSS version 22.

Results

Individually, the single SNPs were not associated with CAD (p < 0.05). However, the combined GRS of 6 SNPs was significantly higher in cases than controls (4.89 ± 0.11 vs 4.58 ± 0.08, p = 0.024). Among blood lipids, GRS showed significant positive association with serum triglycerides levels (p = 0.022).

Conclusion

The GRS was quantitatively associated with CAD risk and showed association with serum triglycerides levels, suggesting that the mechanism of these variants is likely to be in part at least through creating an atherogenic lipid profile in subjects carrying high numbers of risk alleles.

Electronic supplementary material

The online version of this article (10.1186/s12944-018-0736-2) contains supplementary material, which is available to authorized users.

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.

Sortilin and Its Multiple Roles in Cardiovascular and Metabolic Diseases

Cardiovascular disease is a leading cause of morbidity and mortality in the Western world. Studies of sortilin's influence on cardiovascular and metabolic diseases goes far beyond the genome-wide association studies that have revealed an association between cardiovascular diseases and the 1p13 locus that encodes sortilin. Emerging evidence suggests a significant role of sortilin in the pathogenesis of vascular and metabolic diseases; this includes type II diabetes mellitus via regulation of insulin resistance, atherosclerosis through arterial wall inflammation and calcification, and dysregulated lipoprotein metabolism. Sortilin is also known for its functional role in neurological disorders. It serves as a key receptor for cytokines, lipids, and enzymes and participates in pathological cargo loading to and trafficking of extracellular vesicles. This article provides a comprehensive review of sortilin's contributions to cardiovascular and metabolic diseases but focuses particularly on atherosclerosis. We summarize recent clinical findings that suggest that sortilin may be a cardiovascular risk biomarker and also discuss sortilin as a potential drug target.

Association of the genetic markers for myocardial infarction with sudden cardiac death

OBJECTIVE

Investigate the association of rs17465637 gene MIAF3 (1q41), rs1376251 gene TAS2R50 (12p13), rs4804611 gene ZNF627 (19p13), rs619203 gene ROS1 (6q22), rs1333049 (9p21), rs10757278 (9p21), rs2549513 (16q23), rs499818 (6p24) associated with myocardial infarction available from the international genome-wide studies with sudden cardiac death (SCD) in a case-control study.

METHODS

A sample of SCD cases (n=285) was formed using the WHO criteria; the control sample (n=421) was selected according to sex and age. DNA was isolated by phenol-chloroform extraction from the myocardial tissue of SCD cases and blood of control cases. The groups were genotyped for the selected SNPs by real-time PCR using TaqMan probes (Applied Biosystems, United States).

RESULTS

No statistically significant differences in the genotype and allelic frequencies of studied single nucleotide polymorphisms between sudden cardiac death cases and control were detectable in general group. By separating the groups of sex and age differences in the genotype frequencies of rs1333049, rs10757278 and rs499818 are statistical significance. Genotypes CC of rs1333049 and GG of rs10757278 are associated with an increased sudden cardiac death risk in men (p=0.019, OR=1.7, 95% CI 1.1-2.8; p=0.011, OR=1.8, 95% CI 1.2-2.8, respectively). Genotype AG of rs499818 is associated with an increased sudden cardiac death risk in the women over 50 years old (p=0.009, OR=2.4, 95% CI 1.3-4.6).

CONCLUSION

Polymorphisms rs1333049 and rs10757278 are associated with SCD in men and rs499818 in the women aged over 50 years.

Identification of a molecular signaling gene-gene regulatory network between GWAS susceptibility genes ADTRP and MIA3/TANGO1 for coronary artery disease

Coronary artery disease (CAD) is the leading cause of death worldwide. GWAS have identified >50 genomic loci for CAD, including ADTRP and MIA3/TANGO1. However, it is important to determine whether the GWAS genes form a molecular network. In this study, we have uncovered a novel molecular network between ADTRP and MIA3/TANGO1 for the pathogenesis of CAD. We showed that knockdown of ADTRP expression markedly down-regulated expression of MIA3/TANGO1. Mechanistically, ADTRP positively regulates expression of PIK3R3 encoding the regulatory subunit 3 of PI3K, which leads to activation of AKT, resulting in up-regulation of MIA3/TANGO1. Both ADTRP and MIA3/TANGO1 are involved in endothelial cell (EC) functions relevant to atherosclerosis. Knockdown of ADTRP expression by siRNA promoted oxidized-LDL-mediated monocyte adhesion to ECs and transendothelial migration of monocytes, inhibited EC proliferation and migration, and increased apoptosis, which was reversed by expression of constitutively active AKT1 and MIA3/TANGO1 overexpression, while the over-expression of ADTRP in ECs blunted these processes. Knockdown of MIA3/TANGO1 expression also promoted monocyte adhesion to ECs and transendothelial migration of monocytes, and vice versa for overexpression of MIA3/TANGO1. We found that ADTRP negatively regulates the levels of collagen VII and ApoB in HepG2 and endothelial cells, which are downstream regulatory targets of MIA3/TANGOI. In conclusion, we have uncovered a novel molecular signaling pathway for the pathogenesis of CAD, which involves a novel gene-gene regulatory network. We show that ADTRP positively regulates PIK3R3 expression, which leads to activation of AKT and up-regulation of MIA3/TANGO1, thereby regulating endothelial cell functions directly relevant to atherosclerosis.

Identification of Genetic Variants Linking Protein C and Lipoprotein Metabolism: The ARIC Study (Atherosclerosis Risk in Communities)

OBJECTIVE

Previous studies have identified common genetic variants in 4 chromosomal regions that together account for 14% to 15% of the variance in circulating levels of protein C. To further characterize the genetic architecture of protein C, we obtained denser coverage at some loci, extended investigation of protein C to low-frequency and rare variants, and searched for new associations in genes known to influence protein C.

APPROACH AND RESULTS

Genetic associations with protein C antigen level were evaluated in ≤10 778 European and 3190 black participants aged 45 to 64 years. Analyses included >26 million autosomal variants available after imputation to the 1000 Genomes reference panel along with additional low-frequency and rare variants directly genotyped using the Illumina ITMAT-Broad-CARe chip and Illumina HumanExome BeadChip. Genome-wide significant associations (P<5×10^-8) were found for common variants in the GCKR, PROC, BAZ1B, and PROCR-EDEM2 regions in whites and PROC and PROCR-EDEM2 regions in blacks, confirming earlier findings. In a novel finding, the low-density lipoprotein cholesterol-lowering allele of rs12740374, located in the CELSR2-PSRC1-SORT1 region, was associated with lower protein C level in both whites and blacks, reaching genome-wide significance in a meta-analysis combining results from both groups (P=1.4×10^-9). To further investigate a possible link between lipid metabolism and protein C level, we conducted Mendelian randomization analyses using 185 lipid-related genetic variants as instrumental variables. The results indicated that triglycerides, and possibly low-density lipoprotein cholesterol, influence protein C levels.

CONCLUSIONS

Discovery of variants influencing circulating protein C levels in the CELSR2-PSRC1-SORT1 region may indicate a novel genetic link between lipoprotein metabolism and hemostasis.

From Loci to Biology: Functional Genomics of Genome-Wide Association for Coronary Disease

Genome-wide association studies have provided a rich collection of ≈ 58 coronary artery disease (CAD) loci that suggest the existence of previously unsuspected new biology relevant to atherosclerosis. However, these studies only identify genomic loci associated with CAD, and many questions remain even after a genomic locus is definitively implicated, including the nature of the causal variant(s) and the causal gene(s), as well as the directionality of effect. There are several tools that can be used for investigation of the functional genomics of these loci, and progress has been made on a limited number of novel CAD loci. New biology regarding atherosclerosis and CAD will be learned through the functional genomics of these loci, and the hope is that at least some of these new pathways relevant to CAD pathogenesis will yield new therapeutic targets for the prevention and treatment of CAD.

Investigation of KIF6 Trp719Arg gene polymorphism in a case-control study of coronary artery disease and non-fatal myocardial infarction in the Eastern Province of Saudi Arabia

BACKGROUND

Kinesin-like protein 6 (KIF6), a member of the kinesin superfamily, is involved in intracellular transport. A few prospective studies have shown the KIF6 variant Trp719Arg (rs20455) to be associated with coronary artery disease (CAD) in Caucasian populations. However, recent genome-wide association studies on CAD have not proven these associations.

OBJECTIVES

Since the role of KIF6 719Arg allele in other ethnic populations is largely unknown, we sought to determine whether the KIF6 719Arg allele is associated with CAD in an ethnic Middle Eastern population.

DESIGN

Case-control study.

SETTING

CAD patients and control subjects from King Fahd Hospital of the University, Al-Khobar, Saudi Arabia.

PATIENTS AND METHODS

The study population included angiographically defined CAD patients (n=1002) and controls (n=984) with a normal electrocardiogram.

MAIN OUTCOME MEASURE(S)

Association of KIF6 Trp719Arg mutation with CAD.

RESULTS

The KIF6 Trp719Arg polymorphism was not associated with CAD (OR 0.976, 95% CI 0.861-1.105; P=.704). In addition, KIF6 Trp719Arg polymorphism showed a lack of association even in stratified myocardial infarction patients (n=802) (OR 1.006, 95% CI 0.881-1.148; P=.929) in comparison to controls.

CONCLUSIONS

The absence of Trp719Arg polymorphism association with CAD and CAD in stratified myocardial infarction cases indicates that the polymorphism is not associated with an increased risk among CAD patients from the Eastern Province of Saudi Arabia.

LIMITATIONS

Unavailability of data on statin usage among the patient population.

Zinc Finger 259 Gene Polymorphism rs964184 is Associated with Serum Triglyceride Levels and Metabolic Syndrome

Metabolic syndrome (MetS) is characterized by a cluster of cardiovascular risk factors that include: abdominal obesity, dyslipidaemia, hypertension, insulin resistance and impaired glucose tolerance. Recent genome wide association studies have identified several susceptibility regions involved in lipid metabolism that are also associated with MetS. We have explored the association of 9 genetic polymorphisms involved in lipid metabolism and hypertension, including: MTHFR C677T, SELE L554F, FGB - 455G>A, GNB3 C825T, ZNF259 C>G, PSRC-1 A>G, CETP I405V, LPL S447X and LPA C>T in 97 subjects with MetS and 96 individuals without MetS who were recruited randomly from Mashhad stroke and heart atherosclerotic disorder (MASHAD) study using a stratified cluster random sampling technique. Anthropometric parameters and biochemical measurements were determined in all the subjects. Genotyping was carried out followed by univariate and multivariate analyses. The subjects with MetS had a higher triglyceride and lower HDL- C. CG+ GG genotypes of ZNF259 polymorphism (rs964184 C>G) and TT+CT genotypes of MTHFR C677T (rs1801133) were associated with MetS, and individuals carrying the G allele for ZNF259 or the T allele for MTHFR polymorphisms were associated with MetS (e.g, odds ratio (OR) for CG+GG genotypes vs. CC wild type: 2.52, CI=1.33-4.77; P=0.005). However, after multiple comparison adjustment, this relationship remained significant only for CG+ GG genotypes of ZNF259 polymorphism. Moreover, the ZNF259 CG+ GG genotypes were associated with increased serum concentrations of triglycerides and LDL-C, compared to the wild type. These data support the necessity for further studies in larger multicenter settings.

Genetic Basis of Common Human Disease: Insight into the Role of Missense SNPs from Genome-Wide Association Studies

Recent genome-wide association studies (GWAS) have led to the reliable identification of single nucleotide polymorphisms (SNPs) at a number of loci associated with increased risk of specific common human diseases. Each such locus implicates multiple possible candidate SNPs for involvement in disease mechanism. A variety of mechanisms may link the presence of an SNP to altered in vivo gene product function and hence contribute to disease risk. Here, we report an analysis of the role of one of these mechanisms, missense SNPs (msSNPs) in proteins in seven complex trait diseases. Linkage disequilibrium information was used to identify possible candidate msSNPs associated with increased disease risk at each of 356 loci for the seven diseases. Two computational methods were used to estimate which of these SNPs has a significant impact on in vivo protein function. 69% of the loci have at least one candidate msSNP and 33% have at least one predicted high-impact msSNP. In some cases, these SNPs are in well-established disease-related proteins, such as MST1 (macrophage stimulating 1) for Crohn's disease. In others, they are in proteins identified by GWAS as likely candidates for disease relevance, but previously without known mechanism, such as ADAMTS13 (ADAM metallopeptidase with thrombospondin type 1 motif, 13) for coronary artery disease. In still other cases, the missense SNPs are in proteins not previously suggested as disease candidates, such as TUBB1 (tubulin, beta 1, class VI) for hypertension. Together, these data support a substantial role for this class of SNPs in susceptibility to common human disease.

Rs6922269 marker at the MTHFD1L gene predict cardiovascular mortality in males after acute coronary syndrome

Myocardial infarction (MI) is the leading cause of death in industrialized countries. All the traditional risk factors for MI are responsible for approximately 50% of cases of MI cases. Attention therefore has recently focused on genetic variants that are not associated with conventional risk factors. One of them is the marker rs6922269, which has been suggested as a risk factor for development of MI in Western populations. We analyzed the relationship between rs6922269 variant on MTHFD1L gene and (i) risk of the acute coronary syndrome (ACS) in the Czech population and (ii) mortality in 7 years follow up. Rs6922269 (G>A) variant was analyzed (CR 99.3% for patients and 98.0% for controls) by PCR-RFLP in consecutively examined 1614 men and 503 women with ACS (age below 65 years) and in population-based controls--1191 men and 1368 women (aged up to 65 years). ANOVA and Chi square were used for statistical analysis. The genotype frequencies were almost identical (P=0.87) in the ACS patients and in controls and no differences were observed, if males (P=0.73) and females (P=0.93) were analysed separately. In addition, rs6922269 polymorphism was not associated with the classical risk factors (dyslipidemia, hypertension, obesity, smoking, diabetes) in control population. Cardiovascular mortality was significantly higher in males, carriers of the AA genotype (P<0.001, OR 2.52, 95% CI 1.40-4.55, for AA vs. +G). We conclude, that rs6922269 variant at MTHFD1L gene could be an important prognostic factor for cardiovascular mortality in patients after ACS.

Multiancestral analysis of inflammation-related genetic variants and C-reactive protein in the population architecture using genomics and epidemiology study

BACKGROUND

C-reactive protein (CRP) is a biomarker of inflammation. Genome-wide association studies (GWAS) have identified single-nucleotide polymorphisms (SNPs) associated with CRP concentrations and inflammation-related traits such as cardiovascular disease, type 2 diabetes mellitus, and obesity. We aimed to replicate previous CRP-SNP associations, assess whether these associations generalize to additional race/ethnicity groups, and evaluate inflammation-related SNPs for a potentially pleiotropic association with CRP.

METHODS AND RESULTS

We selected and analyzed 16 CRP-associated and 250 inflammation-related GWAS SNPs among 40 473 African American, American Indian, Asian/Pacific Islander, European American, and Hispanic participants from 7 studies collaborating in the Population Architecture using Genomics and Epidemiology (PAGE) study. Fixed-effect meta-analyses combined study-specific race/ethnicity-stratified linear regression estimates to evaluate the association between each SNP and high-sensitivity CRP. Overall, 18 SNPs in 8 loci were significantly associated with CRP (Bonferroni-corrected P<3.1×10(-3) for replication, P<2.0×10(-4) for pleiotropy): Seven of these were specific to European Americans, while 9 additionally generalized to African Americans (1), Hispanics (5), or both (3); 1 SNP was seen only in African Americans and Hispanics. Two SNPs in the CELSR2/PSRC1/SORT1 locus showed a potentially novel association with CRP: rs599839 (P=2.0×10(-6)) and rs646776 (P=3.1×10(-5)).

CONCLUSIONS

We replicated 16 SNP-CRP associations, 10 of which generalized to African Americans and/or Hispanics. We also identified potentially novel pleiotropic associations with CRP for two SNPs previously associated with coronary artery disease and/or low-density lipoprotein-cholesterol. These findings demonstrate the benefit of evaluating genotype-phenotype associations in multiple race/ethnicity groups and looking for pleiotropic relationships among SNPs previously associated with related phenotypes.

The involvement of multiple thrombogenic and atherogenic markers in premature coronary artery disease

OBJECTIVE

To examine the association of atherogenic and thrombogenic markers and lymphotoxin-alfa gene mutations with the risk of premature coronary disease.

METHODS

This cross-sectional, case-control, age-adjusted study was conducted in 336 patients with premature coronary disease (<50 years old) and 189 healthy controls. The control subjects had normal clinical, resting, and exercise stress electrocardiographic assessments. The coronary disease group patients had either angiographically documented disease (>50% luminal reduction) or a previous myocardial infarction. The laboratory data evaluated included thrombogenic factors (fibrinogen, protein C, protein S, and antithrombin III), atherogenic factors (glucose and lipid profiles, lipoprotein(a), and apolipoproteins AI and B), and lymphotoxin-alfa mutations. Genetic variability of lymphotoxin-alfa was determined by polymerase chain reaction analysis.

RESULTS

Coronary disease patients exhibited lower concentrations of HDL-cholesterol and higher levels of glucose, lipoprotein(a), and protein S. The frequencies of AA, AG, and GG lymphotoxin-alfa mutation genotypes were 55.0%, 37.6%, and 7.4% for controls and 42.7%, 46.0%, and 11.3% for coronary disease patients (p = 0.02), respectively. Smoking, dyslipidemia, family history, and lipoprotein(a) and lymphotoxin-alfa mutations in men were independent variables associated with coronary disease. The area under the curve (C-statistic) increased from 0.779 to 0.802 (p<0.05) with the inclusion of lipoprotein(a) and lymphotoxin-alfa mutations in the set of conventional risk factors.

CONCLUSIONS

The inclusion of lipoprotein(a) and lymphotoxin-alfa mutations in the set of conventional risk factors showed an additive but small increase in the risk prediction of premature coronary disease.

Meta-analysis identifies robust association between SNP rs17465637 in MIA3 on chromosome 1q41 and coronary artery disease

Several large-scale meta-GWAS identified significant association between SNP rs17465637 in the MIA3 gene and coronary artery disease (CAD) in the European ancestry populations. However, three follow-up replication studies in the Chinese populations yielded inconsistent results. In order to unequivocally determine whether SNP rs17465637 is associated with CAD, we performed an independent case control association study in the Chinese Han population and a follow-up large scale meta-analysis for SNP rs17465637. Our study included 2503 CAD patients and 2920 non-CAD controls of the Chinese Han origin. A significant association was found between SNP rs17465637 and CAD (P = 0.01, OR = 1.11). Meta-analysis included 7263 CAD patients and 8347 controls combined from five Asian populations. The association between SNP rs17465637 and CAD became highly significant (P = 4.97 × 10(-5), OR = 1.11). Similar analysis also identified significant association between SNP rs17465637 and MI (2424 cases vs. 6,536controls; P = 5.00 × 10(-3), OR = 1.10). We conclude that SNP rs17465637 in MIA3 is indeed a genetic risk factor for CAD across different ethnic populations.

A genome-wide association study of a coronary artery disease risk variant

Although over 30 common genetic susceptibility loci have been identified to be independently associated with coronary artery disease (CAD) risk through genome-wide association studies (GWAS), genetic risk variants reported to date explain only a small fraction of heritability. To identify novel susceptibility variants for CAD and confirm those previously identified in European population, GWAS and a replication study were performed in the Koreans and Japanese. In the discovery stage, we genotyped 2123 cases and 3591 controls with 521 786 SNPs using the Affymetrix SNP Array 6.0 chips in Korean. In the replication, direct genotyping was performed using 3052 cases and 4976 controls from the KItaNagoya Genome study of Japan with 14 selected SNPs. To maximize the coverage of the genome, imputation was performed based on 1000 Genome JPT+CHB and 5.1 million SNPs were retained. CAD association was replicated for three GWAS-identified loci (1p13.3/SORT1 (rs599839), 9p21.3/CDKN2A/2B (rs4977574), and 11q22.3/ PDGFD (rs974819)) in Koreans. From GWAS and a replication, SNP rs3782889 showed a strong association (combined P=3.95 × 10(-14)), although the association of SNP rs3782889 doesn't remain statistically significant after adjusting for SNP rs11066015 (proxy SNP with BRAP (r(2)=1)). But new possible CAD-associated variant was observed for rs9508025 (FLT1), even though its statistical significance did marginally reach at the genome-wide a significance level (combined P=6.07 × 10(-7)). This study shows that three CAD susceptibility loci, which were previously identified in European can be directly replicated in Koreans and also provides additional evidences implicating suggestive loci as risk variants for CAD in East Asian.

Meta-analyses of KIF6 Trp719Arg in coronary heart disease and statin therapeutic effect

Aims

The goal of our study is to assess the contribution of KIF6 Trp719Arg to both the risk of CHD and the efficacy of statin therapy in CHD patients.

Methods and Results

Meta-analysis of 8 prospective studies among 77,400 Caucasians provides evidence that 719Arg increases the risk of CHD (P<0.001, HR = 1.27, 95% CI = 1.15–1.41). However, another meta-analysis of 7 case-control studies among 65,200 individuals fails to find a significant relationship between Trp719Arg and the risk of CHD (P = 0.642, OR = 1.02, 95% CI = 0.95–1.08). This suggests that the contribution of Trp719Arg to CHD varies in different ethnic groups. Additional meta-analysis also shows that statin therapy only benefit the vascular patients carry 719Arg allele (P<0.001, relative ratio (RR) = 0.60, 95% CI = 0.54–0.67). To examine the role of this genetic variant in CHD risk in Han Chinese, we have conducted a case-control study with 289 CHD cases, 193 non-CHD controls, and 329 unrelated healthy volunteers as healthy controls. On post hoc analysis, significant allele frequency difference of 719Arg is observed between female CHD cases and female total controls under the dominant model (P = 0.04, χ² = 4.228, df = 1, odd ratio (OR) = 1.979, 95% confidence interval (CI) = 1.023–3.828). Similar trends are observed for post hoc analysis between female CHD cases and female healthy controls (dominant model: P = 0.04, χ² = 4.231, df = 1, OR = 2.015, 95% CI = 1.024–3.964). Non-genetic CHD risk factors are not controlled in these analyses.

Conclusions

Our meta-analysis demonstrates the role of Trp719Arg of KIF6 gene in the risk of CHD in Caucasians. The meta-analysis also suggests the role of this variant in statin therapeutic response in vascular diseases. Our case-control study suggests that Trp719Arg of KIF6 gene is associated with CHD in female Han Chinese through a post hoc analysis.

Genomic Medicine: Why Do "Similar" Patients Have Different Outcomes?

Genomic variation is an important factor in why supposedly "similar" patients react differently to drugs, have different disease course(s), and varying clinical outcomes. This review provides an update on concepts in modern genomic medicine with an emphasis on clinically relevant study approaches, disease/drug pathway analysis, and recent pharmacogenomic findings. The application of genomic medicine and its importance for rapid diagnosis of disease-causing agents, as well as its clinical application in human disease diagnosis/treatment and in cardiovascular disease are discussed. In addition to direct clinical applications, modern genomic approaches also play an important role in elucidating new mechanisms of disease. Finally, the role of the National Institutes of Health national pharmacogenomics research network in codifying "bench to bedside" translation of genetic results that impact drug therapy will also be discussed.

"My parents died of myocardial infarction: is that my destiny?"

This article presents an overview of clinical and molecular genetics of myocardial infarction (MI). Discussion includes the partial overlapping of risk factors for myocardial infarction and atherosclerosis, the impact of a positive family history on the risk of MI, the "familial" nongenetic, environmental factors, the inherited risk associated with the low-dose input of many genes, and a simple approach to stratify the individual risk in genetic counseling.

Significant associations of the rs2943634 (2q36.3) genetic polymorphism with adiponectin, high density lipoprotein cholesterol and ischemic stroke

BACKGROUND

rs2943634 C/A single nucleotide polymorphism (SNP), located in a non coding region of chromosome 2q36.3, has been associated with coronary artery disease in two genome wide association studies. Our goal was to investigate its relation with myocardial infarction (MI) and ischemic stroke (IS), as well as with 12 intermediate risk phenotypes, in a population-based prospective cohort study.

METHODS

rs2943634 was genotyped in a case-cohort study including a random sample of 1891 individuals (subcohort) and all incident MI (n=211) and IS (n=144) cases during a mean follow-up of 8.2±2.2years, nested within the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam cohort comprising 27,548 middle-aged men and women.

RESULTS

rs2943634 minor allele (A) was associated in an additive fashion with lower risk of IS but not with MI [hazard ratio (HR)=0.66; 95% confidence interval (CI): 0.50-0.87; P=0.003; HR=1.02; 95% CI: 0.82-1.28; P=0.83 respectively, for the age and sex adjusted model]. Furthermore, it was related to slightly higher levels of plasma adiponectin [CC 6.94, CA 7.27, AA 7.86μg/ml, P=0.0002] and high density lipoprotein (HDL)-cholesterol (CC 52.08, CA 53.05 and AA 55.27mg/dl, P=0.002), based on additive models. Adjustment for adiponectin and HDL-cholesterol did not attenuate the association between the SNP and IS risk. In contrast, adjustment for adiponectin abolished the association between the SNP and HDL-cholesterol and adjustment for HDL-cholesterol attenuated the association between the SNP and adiponectin.

CONCLUSIONS

Our findings suggest that rs2943634 is associated with IS risk and with plasma levels of HDL-cholesterol and adiponectin in this German population. Further investigations are needed to confirm these results and to clarify the mechanisms underlying the association.