The impact of newly identified loci on coronary heart disease, stroke and total mortality in the MORGAM prospective cohorts

CDKN2B-AS1 gene rs4977574 A/G polymorphism and coronary heart disease: A meta-analysis of 40,979 subjects

It has been implied that there is a possible relationship between cyclin‐dependent protein kinase inhibitors antisense RNA 1 (CDKN2B‐AS1) gene rs4977574 A/G polymorphism and coronary heart disease (CHD) susceptibility. However, as the research results are discrepant, no distinct consensus on this issue has been reached so far. In order to further elaborate the latent association of the CDKN2B‐AS1 gene rs4977574 A/G polymorphism and CHD, this present meta‐analysis was conducted. There were 40,979 subjects of 17 individual studies in the present meta‐analysis. The pooled odds ratios (ORs) and their corresponding 95% confidence intervals (CIs) were estimated to determine the association strength. Considering the significant heterogeneity among the individual studies, the random‐effect models were used. In the current meta‐analysis, a significant association between CDKN2B‐AS1 gene rs4977574 A/G polymorphism and CHD was found under allelic (OR: 1.18, 95% CI: 1.08–1.29, p = 4.83×10⁻⁴), recessive (OR: 1.36, 95% CI: 1.11–1.67, p = 0.003), dominant (OR: 0.71, 95% CI: 0.58–0.86, p = 6.26×10⁻⁴), heterozygous (OR:1.210, 95% CI: 1.076–1.360, p = 0.001), homozygous (OR: 1.394, 95% CI: 1.163–1.671, p = 3.31×10⁻⁴) and additive (OR: 1.180, 95% CI: 1.075–1.295, p = 4.83×10⁻⁴) genetic models. A more significant association between them was found in the Asian population than that in the whole population under these genetic models (p < 0.05). However, no significant association between them was found in the Caucasian population (p > 0.05). CDKN2B‐AS1 gene rs4977574 A/G polymorphism was associated with CHD susceptibility, especially in the Asian population. G allele of CDKN2B‐AS1 gene rs4977574 A/G polymorphism is the risk allele for CHD.

ANRIL rs1333049 C/G polymorphism and coronary artery disease in a North Indian population - Gender and age specific associations

Many studies conducted worldwide substantiate a role of genetic polymorphisms in non-coding regions linked with coronary artery disease (CAD). One such single nucleotide polymorphism (SNP) of a non-coding RNA in the INK4 locus (ANRIL) i.e. rs1333049 C/G in the vicinity of cell cycle regulating genes is documented to have a role in CAD risk. In this study we aimed to determine the association of ANRIL rs1333049 C/G with CAD in a North Indian population. Five hundred disease free controls and 500 CAD patients were genotyped using allele specific ARMS-PCR method. High risk association of rs1333049 was seen in both heterozygous and mutant genotypes (OR=2.883, 95% CI=1.475-5.638 and p=0.002 and OR=6.717, 95% CI=3.444-13.102 and p < 0.001 respectively). Gender stratified analysis revealed risk association in both heterozygous and mutant genotypes in males. However, risk association in the mutant genotype and females was documented. Similarly, risk association was seen in subjects above 40 years of age in heterozygous and mutant genotypes. Similarly, risk association was reported in obese, sedentary lifestyle, positive family history and smoking in the heterozygous and mutant genotype and with diabetes in the mutant GG genotype. The study revealed high risk association of ANRIL rs1333049 with CAD and other risk factors.

Details on high frequency blood collection, data analysis, available material and patient characteristics in BIOMArCS

The Biomarker Study to Identify the Acute Risk of a Coronary Syndrome (BIOMArCS) is a prospective, observational study that has been designed to study the evolution of blood biomarkers in post-acute coronary syndrome (ACS) patients. In our recently published study "Temporal evolution of Myeloperoxidase and Galectin 3 during 1 year after acute coronary syndrome admission" [1] in the American Heart Journal, we demonstrated that repeatedly measuring MPO and Galectin-3 does not aid to differentiate between patients with and without adverse cardiac events during 1-year follow-up. In this Data-In-Brief article, we present further details on data collections and data analysis. In addition, a detailed description of baseline characteristics and the distribution of blood sampling moments is provided. The BIOMArCS dataset contains clinical information and follow-up data on all enrolled 844 patients. These patients underwent a median of 17 (25th -75th percentile 12-20) repeated blood samples in the first year after the index ACS. Blood samples were stored at -80 °C within a median of 82 (25th-75th percentile 58-117) minutes after withdrawal. We collected whole blood, citrate plasma, EDTA plasma, serum and DNA. The dataset used for the analysis in the accompanying research paper has been made available online. We welcome collaborations for further use of our data, whether or not in combination with other biobanks.

Analysis of Polymorphism rs1333049 (Located at 9P21.3) in the White Population of Western Siberia and Associations with Clinical and Biochemical Markers

The 9p21.3 chromosomal region is a marker of the risk of cardiovascular diseases. The aim of this study was to analyze single-nucleotide polymorphism rs1333049 (chr9:22125504) in the population of Western Siberia (Russia) and possible associations with clinical and biochemical parameters. The population included in the analyses was selected from a sample surveyed within the framework of the Health, Alcohol and Psychosocial Factors In Eastern Europe (HAPIEE) study (9360 participants, >90% white, aged 45-69, males: 50%). In total, 2729 randomly selected patients were included. Plasma lipid levels were determined by standard enzymatic assays. Rs1333049 was analyzed by RT-PCR (BioLabMix, Russia). Frequencies of rs1333049 genotypes C/C (homozygote), C/G (heterozygote), and G/G were 0.22, 0.51, and 0.27 in this population. The Allele G frequency was 0.53. We found an association of allele G with total cholesterol and low-density lipoprotein cholesterol levels among male participants (p = 0.004 and p = 0.002, respectively). Allele C was significantly associated with the risk of myocardial infarction among the male participants (odds ratio 1.96, 95% confidence interval 1.14-3.38, p =  0.017) and the study population (odds ratio 1.83, 95% confidence interval 1.23-2.72, p  =  0.004). Thus, rs1333049 is associated with myocardial infarction in the white population of Western Siberia (Russia).

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.

Common Polymorphisms Linked to Obesity and Cardiovascular Disease in Europeans and Asians are Associated with Type 2 Diabetes in Mexican Mestizos

Background and objectives: Type 2 diabetes (T2D) is a major problem of public health in Mexico. We investigated the influence of five polymorphisms, previously associated with obesity and cardiovascular disease in Europeans and Asians, on T2D in Mexican Mestizos. Materials and Methods: A total of 1358 subjects from 30 to 85 years old were genotyped for five loci: CXCL12 rs501120; CDNK2A/B rs1333049; HNF-1α rs2259816; FTO rs9939609; and LEP rs7799039. We used logistic regressions to test the effect of each locus on T2D in two case⁻control groups with obesity and without obesity. Also, linear regression models on glucose and glycated hemoglobin (HbA1c) were carried out on the whole sample, adjusted by age, gender, and body mass index. Results: The CXCL12 rs501120 C allele (OR = 1.96, p = 0.02), the FTO rs9939609 A allele (OR = 2.20, p = 0.04) and the LEP rs7799039 A allele (OR = 0.6, p = 0.03) were significantly associated with T2D in obesity case⁻control group. No significant association was found in the non-obesity case⁻control group. The linear regression model showed that CDNK2A/B rs1333049 C allele (β = 0.4, p = 0.03) and FTO rs9939609 A allele (β = 0.5, p = 0.03), were significantly associated with HbA1c, but no association was found among the loci with the glucose levels. Conclusions: Polymorphisms previously linked with obesity and cardiovascular events were also associated with T2D and high levels of HbA1c. Furthermore, we must point at the fact that this is the first report where polymorphisms CXCL12 rs501120 and LEP rs7799039 are associated with T2D in subjects with obesity.

Dietary patterns interact with chromosome 9p21 rs1333048 polymorphism on the risk of obesity and cardiovascular risk factors in apparently healthy Tehrani adults

PURPOSE

Gene-dietary patterns may contribute to determining body composition and related biochemical indices. The aim of this study was to evaluate interactions between rs1333048 polymorphism and major dietary patterns on body fat percentage, general and central obesity, and related biochemical measurements.

METHODS

This cross-sectional study was conducted on 265 healthy Tehrani adults with mean age of 35 years (47.5% men, 52.5% women). Dietary patterns (DPs) were extracted by factor analysis. Bioelectrical impedance analysis was used for body analysis and rs1333048 was genotyped by the restriction fragment length polymorphism (PCR-RFLP) method.

RESULTS

Three DPs were extracted: restricted refined grains DP, legumes DP and healthy DP. AA genotype compared to CC genotype had greater odds for general obesity before (OR 3.14; 95% CI 1.008-9.60, P = 0.045) and after (OR 3.11; 95% CI 1.008-9.60, P = 0.048) adjusting for potential confounders. Individuals with AA genotype were more likely to be centrally obese before (OR 2.09; 95% CI 1.006-4.35, P = 0.048) and after (OR 2.63; 95% CI 1.12-6.17, P = 0.026) controlling for potential confounders. Significant interactions were observed between Legumes DP and rs1333048 SNP on waist circumference (P = 0.047), body fat % (BFP) (P = 0.048), hs-Crp (P = 0.042), BMI (P = 0.073), WHtR (P = 0.063) and odds for general obesity (P = 0.051). Following this DP reduced all these items for individuals with CC genotype, whereas increased them for people who carry CA or AA genotypes.

CONCLUSIONS

The findings indicate that there are significant associations between AA genotype of rs1333048 SNP and general and central obesity, and significant interaction between alleles of this SNP and major dietary patterns on the odds of general obesity, BFP, waist circumference, BMI, WHtR and hs-Crp.

9p21.3 risk locus is associated with first-ever myocardial infarction in an Austrian cohort

AIMS

Atherosclerosis often presents as a complex systemic disease that is strongly influenced by lifestyle factors, but also by the genetic background. The sequence variant rs1333049 affects the expression of ANRIL, a noncoding RNA transcript playing a key role in the regulation of inflammatory processes. We thus aimed to replicate the predictive value of genetic information on this variant regarding the development of cardiovascular events in an Austrian high-risk cohort.

METHODS

Nine hundred and eighty-eight patients from an angiologic outpatient ward at a large University hospital were genotyped by means of the 5'-nuclease assay. Relative risk ratios were assessed for carriers of different alleles. Statistical independence of genetic information was evaluated in multivariable analysis including known risk markers.

RESULTS

In patients carrying the [G]-allele, metabolic parameters (serum low-density lipoprotein, total cholesterol) significantly decreased during the initial 6 months of the observation period (P < 0.01). Likewise, homozygous [C]-allele carriers were at a higher risk of suffering myocardial infarction (relative risk = 2.681, 95% confidence interval 1.418-5.070). In contrast, we found no interaction between rs1333049 genotype and progression of carotid atherosclerosis or stroke.

CONCLUSIONS

These results are in line with the previous findings, suggesting that genetic information on the rs1333049 variant might be a useful predictor of adverse cardiac events. Thus, we could successfully replicate the predictive value of the 9p21 risk allele in an Austrian cohort.

Association of CDKN2B-AS1 rs1333049 with Brain Diseases: A Case-control Study and a Meta-analysis

Objective

CDKN2B-AS1 polymorphisms were shown to associate with the risk of stroke in European. The goal of this study was to evaluate the contribution of CDKN2B-AS1 rs1333049 to the risk of hemorrhagic stroke (HS) and brain tumor (BT) in Han Chinese.

Methods

A total of 142 HSs, 115 BTs, and 494 controls were included in the current association study. The genotyping test was performed using the melting temperature shift method.

Results

We failed to validate the association of CDKN2B-AS1 rs1333049 with the risk of brain disease. Significantly higher levels of low-density lipoprotein cholesterol (LDL-C) (p=0.027), high-density lipoprotein cholesterol (HDL-C) (p<0.001) and total cholesterol (TC) (p<0.001) were found in HSs in the genotype GG/GC carriers, but not the genotype CC carriers (p>0.05). The meta-analysis of 10 studies among 133,993 individuals concluded that rs1333049 of CDKN2B-AS1 gene was likely to increase a 16% incidence rate of cerebrovascular disease (CD) among various populations (odds ratio 1.16, 95% confidence interval 1.08–1.25; p<0.0001, random-effect method).

Conclusion

Our case-control study identified rs1333049 genotypes showed different association with the concentration of the LDL-C, HDL-C and TC in the HS patients. Meta-analysis supported the association between rs1333049 and CD risk in various populations, although we were unable to observe association between rs1333049 and the risk of HSs in Han Chinese.

A meta-analysis of three identified single nucleotide polymorphisms at 1p13.3 and 1q41 and their associations with lipid levels and coronary artery disease

The aim of this meta-analysis was to detect whether three identified single nucleotide polymorphisms (SNPs) (rs646776, rs599839, and rs17465637) at 1p13.3 and 1q41 are associated with lipid levels and the risk of coronary artery disease (CAD). Databases of MEDLINE, EMBASE, the Cochrane Library, and BIOSIS were systematically searched. The pooled effects were expressed as odds ratio or standardized mean difference or mean difference with 95% confidence intervals. A total of 14 studies with 57,916 patients were included in the meta-analysis. Pooled effects showed that the AA group of 1p13.3 rs599839 had higher total cholesterol (TC) and low-density lipoprotein cholesterol (LDLC), and lower high-density lipoprotein cholesterol (HDLC) levels than the GA/GG group, and the CAD group had higher AA genotype frequency than the control group. The TT group of 1p13.3 rs646776 had higher TC and LDLC levels and lower HDLC levels than the CT/CC group. The CAD group also had higher CC genotype frequency of 1q41 rs17465637 than the control group. The SNPs of 1p13 rs599839 and rs646776 were associated with serum lipid levels. The genetic variants of 1p13 rs599839 and 1q41 rs17465637 SNPs were prominently related to CAD, and the genetic variants of chromosome 1p13 promote the risk of CAD by increased TC and LDLC levels and decreased HDLC levels.

Prioritizing covariates in the planning of future studies in the meta-analytic framework

Science can be seen as a sequential process where each new study augments evidence to the existing knowledge. To have the best prospects to make an impact in this process, a new study should be designed optimally taking into account the previous studies and other prior information. We propose a formal approach for the covariate prioritization, that is the decision about the covariates to be measured in a new study. The decision criteria can be based on conditional power, change of the p-value, change in lower confidence limit, Kullback-Leibler divergence, Bayes factors, Bayesian false discovery rate or difference between prior and posterior expectation. The criteria can be also used for decisions on the sample size. As an illustration, we consider covariate prioritization based on genome-wide association studies for C-reactive protein levels and make suggestions on the genes to be studied further.

The Effect of FLT1 Variant on Long-Term Cardiovascular Outcomes: Validation of a Locus Identified in a Previous Genome-Wide Association Study

Background

Data on genetic variants that can predict follow-up cardiovascular events are highly limited, particularly for Asians. The aim of this study was to validate the effects of two variants in FLT1 and 9p21 on long-term cardiovascular outcomes in high-risk Korean patients.

Methods

We examined the prognostic values of the rs9508025 and rs1333049 variants that were found to be associated with coronary artery disease (CAD) risk in a previous Korean genome-wide association study. A total of 2693 patients (mean age: 55.2 years; male: 55.2%) with CAD or its risk factors at baseline were enrolled and followed for major adverse cardiac events (MACE).

Results

During the mean follow-up of 8.8 years, 15.4% of the patients experienced MACE. Kaplan-Meier curves showed that MACE-free survival was different according to the genotype of rs9508025 (log rank p = 0.02), whereas rs1333049 genotype did not correlate with the prognosis. Multivariate Cox proportional hazard analysis showed that C-allele of rs9508025 was significantly associated with a high rate of MACE, while rs1333049 was not. Further analyses demonstrated that the association of the rs9508025 variant with MACE was mainly due to its relation to coronary revascularization, which was also associated with the rs1333049 variant. In an additional analysis, rs9508025 was found to be an independent determinant of the outcome only in the subgroup with history of CAD.

Conclusions

rs9508025 in FLT1 was significantly associated with long-term cardiovascular events, particularly in patients with prior CAD. The association of rs1333049 in 9p21 was not significant.

The Kalirin Gene rs9289231 Polymorphism as a Novel Predisposing Marker for Coronary Artery Disease

BACKGROUND

Atherosclerosis is the leading cause of death and disability worldwide. Genetic variations play a major role in the process of atherosclerosis. Recently, rs9289231 genetic variations of the Kalirin gene (KALRN) on chromosome 3q21.2 have been introduced as potential genetic markers for coronary artery disease (CAD).

OBJECTIVE

In this case-control study, we investigated the association between genetic susceptibility to CAD and rs9289231 G/T polymorphism, located on the KALRN gene, in an Iranian population.

METHODS

Our cohort consisted of 1486 individuals undergoing coronary angiography. Of these, we considered the 1007 patients with CAD to be case individuals and the 479 individuals with normal coronary conditions to be control individuals. We performed single-nucleotide polymorphism (SNP) genotyping via the high resolution melting (HRM) technique.

RESULTS

Our data showed that the minor allele (G) frequency of rs9289231 SNP was higher in our CAD group than that in our control group (odds ratio, 1:37; confidence interval, 1.07-1.74; P = .01). The results of our data analysis highlighted a genetic association between rs9289231 polymorphism and severity and development of CAD.

CONCLUSIONS

We consider the GG genotype and the G allele of rs9289231 polymorphism of KALRN to be genetic risk factors for CAD in an Iranian population, especially in early-stage atherosclerotic vascular disease.

Association of variants in CELSR2-PSRC1-SORT1 with risk of serum lipid traits, coronary artery disease and ischemic stroke

Recent genome-wide association studies (GWAS) have identified genetic variants associated with coronary artery disease (CAD), ischemic stroke (IS) and serum lipid traits in different ethnic groups. Some loci were found to affect the risk of CAD and IS. However, there were no data in the southern Chinese populations. Our study was to assess the association of CELSR2-PSRC1-SORT1 rs599839, rs464218 and rs6698443 SNPs and serum lipid levels and the risk of CAD and IS. The genotypes of 3 SNPs were detected in 561 CAD and 527 IS patients, and in 590 healthy controls. The genotypic and allelic frequencies of the rs599839 SNP were different between the controls and IS patients (P < 0.05). The minor G alleles of rs599839 and rs464218 SNPs were associated with higher high-density lipoprotein cholesterol concentrations in CAD and IS patients (P < 0.05); respectively. No association was found between the SNPs of rs599839, rs464218 and rs6698843 at the CELSR2-PSRC1-SORT1 and the risk of CAD or IS. These results will be replicated in the other Chinese populations.

The Association between Serum LDL Cholesterol and Genetic Variation in Chromosomal Locus 1p13.3 among Coronary Artery Disease Patients

Background. Several polymorphisms of a locus on chromosome 1p13.3 have a significant effect on low-density lipoprotein cholesterol (LDL-C), atherosclerosis, and acute coronary syndrome (ACS). Methods. We aimed to investigate the association between rs599839, rs646776, and rs4970834 of locus 1p13.3 and serum LDL-C and severity of coronary artery stenosis in ACS patients. Genotyping of the rs599839, rs646776, and rs4970834 polymorphisms was performed on Arab patients undergoing coronary angiography for ACS. Patients were divided into group A (ACS with insignificant stenosis (<50%)) and group B (with significant stenosis (≥50%)). Results. Patients carrying the minor G allele in rs599839 had significantly lower mean of LDL-C (2.58 versus 3.44 mM, P = 0.026) than homozygous A allele carriers (GG versus AA). Carriers of minor C allele in rs64776 had significantly higher mean of HDL-C (2.16 versus 1.36 mM, P = 0.004) than carriers of the T alleles (AA versus GG). The odd ratio and 95% confidence interval for dominant model for G allele carriers of rs599839 were 0.51 (0.30–0.92), P = 0.038, among patients with significant stenosis. Conclusions. Polymorphisms rs646776 and rs599839 of locus 1p13.3 were significantly associated with LDL-C and other lipid parameters. In addition, the G-allele carriers of variant rs599839 had a significant protective effect against the atherosclerosis.

Role of 9p21 and 2q36 variants and arterial stiffness in the prediction of coronary artery disease

BACKGROUND

Genetic polymorphisms and arterial stiffness indices have been associated with cardiovascular prognosis and the presence and extent of angiographic coronary artery disease (CAD). We aimed to investigate whether arterial stiffness indices and 9p21 and 2q36 variants may improve prediction of CAD presence and extent when added to classical cardiovascular risk factors in patients at high risk for CAD.

MATERIALS AND METHODS

In this cross-sectional study, we enrolled 183 consecutive patients with suspected stable CAD (age 61 ± 9 years, 134 males) referred for diagnostic coronary angiography. Framingham risk score (FRS) was calculated. Arterial stiffness was assessed by carotid-femoral pulse wave velocity (PWV) and central augmentation index (AIx) using applanation tonometry. Genetic polymorphisms of 9p21 (rs1333049) and 2q36 (rs2943634) loci were also analysed.

RESULTS

Higher FRS and PWV and the presence of rs2943634 risk allele were independent predictors of CAD (Nagelkerke R(2) 0·252, P < 0·001), while higher FRS and the presence of rs1333049 risk allele were independent predictors of multivessel CAD (Nagelkerke R(2) 0·190, P < 0·001). Genetic polymorphisms and vascular indices did not improve the predictive accuracy of FRS-based models (P > 0·1 for all) for CAD presence or extent.

CONCLUSIONS

In these high-risk patients, 9p21 and 2q36 variants and PWV were independently associated with CAD presence and extent, but the addition of both genetic data and arterial stiffness indices to FRS did not improve the prediction of CAD compared with FRS alone. Further studies are needed to clarify the prognostic role of genetic and vascular indices in the prediction of angiographic CAD.

Creation and Validation of an EMR-based Algorithm for Identifying Major Adverse Cardiac Events while on Statins

Statin medications are often prescribed to ameliorate a patient's risk of cardiovascular events due in part to cholesterol reduction. We developed and evaluated an algorithm that can accurately identify subjects with major adverse cardiac events (MACE) while on statins using electronic medical record (EMR) data. The algorithm also identifies subjects experiencing their first MACE while on statins for primary prevention. The algorithm achieved 90% to 97% PPVs in identification of MACE cases as compared against physician review. By applying the algorithm to EMR data in BioVU, cases and controls were identified and used subsequently to replicate known associations with eight genetic variants. We replicated 6/8 previously reported genetic associations with cardiovascular diseases or lipid metabolism disorders. Our results demonstrated that the algorithm can be used to accurately identify subjects with MACE and MACE while on statins. Consequently, future e studies can be conducted to investigate and validate the relationship between statins and MACE using real-world clinical data.

The rs1333049 polymorphism on locus 9p21.3 and extreme longevity in Spanish and Japanese cohorts

The rs1333049 (G/C) polymorphism located on chromosome 9p21.3 is a candidate to influence extreme longevity owing to its association with age-related diseases, notably coronary artery disease (CAD). We compared allele/genotype distributions of rs1333049 in cases (centenarians) and controls (younger adults, without (healthy) or with CAD) in two independent cohorts: Spanish (centenarians: n = 152, 128 women, 100-111 years; healthy controls: n = 343, 212 women, age <50 years; CAD controls: n = 98, 32 women, age ≤65 years) and Japanese (centenarians: n = 742, 623 women, 100-115 years; healthy controls: n = 920, 511 women, < 60 years; CAD controls: n = 395, 45 women, age ≤65 years). The frequency of the "risk" C-allele tended to be lower in Spanish centenarians (47.0 %) than in their healthy (52.9 %, P = 0.088) or CAD controls (55.1 %, P = 0.078), and significant differences were found in genotype distributions (P = 0.034 and P = 0.045), with a higher frequency of the GG genotype in cases than in both healthy and CAD controls as well as a lower proportion of the CG genotype compared with healthy controls. In the Japanese cohort, the main finding was that the frequency of the C-allele did not differ between centenarians (46.4 %) and healthy controls (47.3 %, P = 0.602), but it was significantly lower in the former than in CAD controls (57.2 %, P < 0.001). Although more research is needed, the present and recent pioneer findings (Rejuvenation Res 13:23-26, 2010) suggest that the rs1333049 polymorphism could be among the genetic contributors to exceptional longevity in Southern European populations, albeit this association does not exist in the healthy (CAD-free) Japanese population.

Association between 9p21 genomic markers and ischemic stroke risk: evidence based on 21 studies

Epidemiological studies indicate a genetic contribution to ischemic stroke risk, but specific genetic variants remain unknown. Recently independent studies reported an association between coronary heart disease and single-nucleotide polymorphisms (SNPs) located at chromosome 9p21 (rs10757278 and proxy SNPs). Given that stroke is a common complication after myocardial infarction, several validation studies have been conducted among various ethnic populations to investigate if the same loci was associated with ischemic stroke (IS), but the results have been inconsistent. To investigate this inconsistency and derive a more precise estimation of the relationship, a meta-analysis of 34,128 cases and 153,428 controls from 21 studies was performed. Potential sources of heterogeneity including ethnicity, sample size, control source and ischemic stroke subtypes were also assessed. Overall, the summary odds ratio of IS was 1.11 (95% CI: 1.07–1.15, P<10⁻⁵) for rs10757278. In the subgroup analysis by ethnicity, significantly increased risks were found in East Asians (3188 cases and 4503 controls; OR = 1.14, 95% CI: 1.07–1.21, P<10⁻⁵) and Caucasians (30505 cases and 145153controls; OR = 1.08, 95% CI: 1.04–1.12, P<10⁻⁵) for the polymorphism; while no significant associations were found among African Americans (435 cases and 3772 controls; OR = 0.97, 95% CI: 0.63–1.51, P = 0.90) in all genetic models. In the subgroup analyses by IS subtypes, significant association was detected only in large vessel stroke group, while no significant associations among small vessel or cardioembolic stroke. When stratified by sample size, and control source, significantly increased risks were found for the polymorphism in all genetic models. This meta-analysis provides accurate and comprehensive estimates of the association of genetic variant at chromosome 9p21 and IS, but these associations vary in different ethnic populations.

Genetic polymorphism rs6922269 in the MTHFD1L gene is associated with survival and baseline active vitamin B12 levels in post-acute coronary syndromes patients

Background and Aims

The methylene-tetrahydrofolate dehydrogenase (NADP+ dependent) 1-like (MTHFD1L) gene is involved in mitochondrial tetrahydrofolate metabolism. Polymorphisms in MTHFD1L, including rs6922269, have been implicated in risk for coronary artery disease (CAD). We investigated the association between rs6922269 and known metabolic risk factors and survival in two independent cohorts of coronary heart disease patients.

Methods and Results

DNA and plasma from 1940 patients with acute coronary syndromes were collected a median of 32 days after index hospital admission (Coronary Disease Cohort Study, CDCS). Samples from a validation cohort of 842 patients post-myocardial infarction (PMI) were taken 24–96 hours after hospitalization. DNA samples were genotyped for rs6922269, using a TaqMan assay. Homocysteine and active vitamin B12 were measured by immunoassay in baseline CDCS plasma samples, but not PMI plasma. All cause mortality was documented over follow-up of 4.1 (CDCS) and 8.8 (PMI) years, respectively. rs6922269 genotype frequencies were AA n = 135, 7.0%; GA n = 785, 40.5% and GG n = 1020, 52.5% in the CDCS and similar in the PMI cohort. CDCS patients with AA genotype for rs6922269 had lower levels of co-variate adjusted baseline plasma active vitamin B12 (p = 0.017) and poorer survival than patients with GG or GA genotype (mortality: AA 19.6%, GA 12.0%, GG 11.6%; p = 0.007). In multivariate analysis, rs6922269 genotype predicted survival, independent of established covariate predictors (p = 0.03). However the association between genotype and survival was not validated in the PMI cohort.

Conclusion

MTHFD1L rs6922269 genotype is associated with active vitamin B12 levels at baseline and may be a marker of prognostic risk in patients with established coronary heart disease.

Genetic variants at chromosome 9p21 and risk of first versus subsequent coronary heart disease events: a systematic review and meta-analysis

Objectives

The purpose of this analysis was to compare the association between variants at the chromosome 9p21 locus (Ch9p21) and risk of first versus subsequent coronary heart disease (CHD) events through systematic review and meta-analysis.

Background

Ch9p21 is a recognized risk factor for a first CHD event. However, its association with risk of subsequent events in patients with established CHD is less clear.

Methods

We searched PubMed and EMBASE for prospective studies reporting association of Ch9p21 with incident CHD events and extracted information on cohort type (individuals without prior CHD or individuals with established CHD) and effect estimates for risk of events.

Results

We identified 31 cohorts reporting on 193,372 individuals. Among the 16 cohorts of individuals without prior CHD (n = 168,209), there were 15,664 first CHD events. Ch9p21 was associated with a pooled hazard ratio (HR) of a first event of 1.19 (95% confidence interval: 1.17 to 1.22) per risk allele. In individuals with established CHD (n = 25,163), there were 4,436 subsequent events providing >99% and 91% power to detect a per-allele HR of 1.19 or 1.10, respectively. The pooled HR for subsequent events was 1.01 (95% confidence interval: 0.97 to 1.06) per risk allele. There was strong evidence of heterogeneity between the effect estimates for first and subsequent events (p value for heterogeneity = 5.6 × 10⁻¹¹). We found no evidence for biases to account for these findings.

Conclusions

Ch9p21 shows differential association with risk of first versus subsequent CHD events. This has implications for genetic risk prediction in patients with established CHD and for mechanistic understanding of how Ch9p21 influences risk of CHD.

Chromosome 1p13 genetic variants antagonize the risk of myocardial infarction associated with high ApoB serum levels

Background

Genetic variation at 1p13 modulates serum lipid levels and the risk of coronary heart disease through the regulation of serum lipid levels. Here we investigate if the interaction between genetic variants at 1p13 and serum lipid levels affects the risk of non-fatal myocardial infarction (MI) in the Stockholm Heart Epidemiology Program (SHEEP), a large population based case control study.

Methods

In the present study only non fatal MI cases (n = 1213, men/women: 852/361) and controls (n = 1516, men/women =1054/507) matched by age, sex and residential area, were included. Three SNPs 12740374 G/T, rs599839A/G and rs646776T/C mapping at 1p13 were analysed for association with serum lipid levels and the risk of MI by a weighted least square regression and logistic regression analyses, respectively. To analyse the effect of the interaction between genetic variants and serum lipid levels on the risk of MI, we applied the biological model of interaction that estimates the difference in risk, expressed as OR (95%CI), observed in the presence and in the absence of both exposures. One derived measure is the Synergy index (S) and 95%CI, where S > 1 indicates synergy and S < 1 antagonism between the two interaction terms.

Results

Rs12740374G/T and rs646776T/C were in strong linkage disequilibrium (LD) (r² = 0.99), therefore only rs599839A/G and rs646776 were included in the analysis. Consistently with published data, presence of the rare genotypes was associated with reduced total-, LDL-cholesterol and ApoB serum levels (all p < 0.05) as compared to the reference genotype, but was not associated with the risk of MI.

However, the increased risk of MI observed in individual exposed to high (≥75^th percentile) serum lipid levels was offset in subjects carrying the rare alleles G and C. In particular, the risk of MI associated with high ApoB serum levels OR (95%CI) 2.27 (1.86-2.77) was reduced to 1.76 (1.33-2.34) in the presence of the G allele at rs599839 with an S of 0.47 (0.20-0.90).

Conclusions

These results indicate that an antagonism between ApoB serum levels and genetic variants at 1p13 contributes to reduce the risk of non-fatal MI in the presence of high ApoB serum levels.

From circulating biomarkers to genomics and imaging in the prediction of cardiovascular events in the general population

Cardiovascular disease (CVD) is the leading cause of death and disability worldwide. In the last decades numerous markers have been considered and investigated for the prediction of CV events, but only a few of them resulted in improved global risk assessment beyond traditional risk factors when incorporated into coronary evaluation scores. Recent genetic studies have pointed out a few but consistent loci or genes which are independently associated with CV risk. The idea is fascinating that these genetic markers could lead to improved individual CV risk assessment and tailored pharmacological interventions. In this brief review we will not make a systematic review of all non-genetic and genetic markers of CV risk but we will try to make a brief overview of the most interesting ones with the aim to underline potential 'pros' and 'cons' of their implementation in clinical practice.

Genetic markers enhance coronary risk prediction in men: the MORGAM prospective cohorts

Background

More accurate coronary heart disease (CHD) prediction, specifically in middle-aged men, is needed to reduce the burden of disease more effectively. We hypothesised that a multilocus genetic risk score could refine CHD prediction beyond classic risk scores and obtain more precise risk estimates using a prospective cohort design.

Methods

Using data from nine prospective European cohorts, including 26,221 men, we selected in a case-cohort setting 4,818 healthy men at baseline, and used Cox proportional hazards models to examine associations between CHD and risk scores based on genetic variants representing 13 genomic regions. Over follow-up (range: 5–18 years), 1,736 incident CHD events occurred. Genetic risk scores were validated in men with at least 10 years of follow-up (632 cases, 1361 non-cases). Genetic risk score 1 (GRS1) combined 11 SNPs and two haplotypes, with effect estimates from previous genome-wide association studies. GRS2 combined 11 SNPs plus 4 SNPs from the haplotypes with coefficients estimated from these prospective cohorts using 10-fold cross-validation. Scores were added to a model adjusted for classic risk factors comprising the Framingham risk score and 10-year risks were derived.

Results

Both scores improved net reclassification (NRI) over the Framingham score (7.5%, p = 0.017 for GRS1, 6.5%, p = 0.044 for GRS2) but GRS2 also improved discrimination (c-index improvement 1.11%, p = 0.048). Subgroup analysis on men aged 50–59 (436 cases, 603 non-cases) improved net reclassification for GRS1 (13.8%) and GRS2 (12.5%). Net reclassification improvement remained significant for both scores when family history of CHD was added to the baseline model for this male subgroup improving prediction of early onset CHD events.

Conclusions

Genetic risk scores add precision to risk estimates for CHD and improve prediction beyond classic risk factors, particularly for middle aged men.

Heterozygote genotypes at rs2222823 and rs2811712 SNP loci are associated with cerebral small vessel disease in Han Chinese population

AIMS

With developments of etiology of cerebral small vessel disease (CSVD) and genome-wide association study (GWAS) of stroke, the genetic studies of CSVD are focused on genes related to blood-brain barrier (BBB) and aging. The project aims to investigate the association between CSVD and susceptibility loci and candidate genes.

METHODS

All study subjects admitted Beijing Tiantan Hospital from June 2009 to September 2010 including 197 cerebral small vessel disease patients(S), 198 large artery atherosclerosis control individuals (vascular stenotic rate ≥50% diameter reduction) (L), 200 hypertensive intracerebral hemorrhage control individuals (H) and 197 stroke-free control individuals (C). 15 SNPs in 4 genes (MYLK, AQP4, NINJ2, and INK4/ARF) were genotyped using Multiplex Snapshot assay. Each SNP was first examined between the groups S and C in different genetic models (codominant, dominant, recessive, overdominant, and log-additive). Permutation correction was used to adjust for multiple testing. The significant SNP loci were further analyzed in comparing S with L and H, respectively. Subgroup analysis was also performed for each risk-factor category.

RESULTS

Among the 15 SNPs, rs2222823 and rs2811712 were found to be significantly associated with CSVD after multiple-testing adjustment. The heterozygote (A/T) of rs2222823 of MYLK has an odds ratio of 0.52 (95% CI =[0.35, 0.79], P= 0.002, adjusted P= 0.031) when compared with homozygotes. The heterozygote (C/T) of rs2811712 of INK4/ARF has an odds ratio of 1.75 (95% CI =[1.13-2.71], P= 0.004, adjusted P= 0.050). The SNP rs2222823 was significant (P= 0.035) in comparing S with H. In comparing S versus L, it is significant for the subgroups of patients without diabetes (P= 0.012) and drinking (P= 0.018). rs2811712 was significant in comparing S with L for the subgroups of patients with hyperlipidemia (P= 0.029) and drinking (P= 0.04).

CONCLUSION

The heterozygotes (T/A) at the rs2222823 SNP locus of MYLK gene decreases the risk of having cerebral small vessel disease, while the heterozygotes (C/T) at the rs2811712 SNP locus of INK4/ARF gene increases the risk, suggesting that the MYLK and INK4/ARF are the associated genes of cerebral small vessel disease in Han Chinese population.

Polymorphisms of the Genes EncodingCD40and Growth Differentiation Factor 15 and in the 9p21.3 Region in Patients with Rheumatoid Arthritis and Cardiovascular Disease

Objective.

Genes or gene products associated with coronary artery disease in the general population were analyzed in rheumatoid arthritis (RA) patients with atherothrombotic manifestations (ATM).

Methods.

A cross-sectional study of 681 individuals (498 women; 183 men) with RA (American College of Rheumatology criteria), a mean age of 60.6 ± 13.2 years, and mean disease duration of 15.5 ± 12.6 years who were consecutively recruited and followed for 6 years. The prevalence of ATM [i.e., myocardial infarction, angina pectoris with intervention, deep vein thrombosis/pulmonary embolism (DVT/PE), and/or stroke/transient ischemic attack (TIA)] was recorded. Polymorphisms were analyzed in the genes coding for growth differentiation factor 15 (GDF15)/monocyte inhibitory cytokine-1 (MIC-1; rs1058587),CD40(rs1535045 and rs3765459), and the 9p21.3 locus (rs1333049). Controls were randomly selected (n = 687; matched for age and sex).

Results.

The distribution of genotypes ofGDF15/MIC-1differed significantly between patients with RA and controls (chi-squared = 6.40, 2 df, p = 0.041). ATM were associated with polymorphism of theGDF15/MIC-1G allele (OR 2.21, 95% CI 1.17–4.18), and with CC genotype of the 9p21.3 locus (rs1333049; OR 1.92, 95% CI 1.15–3.19). Stroke/TIA in women was associated withGDF15/MIC-1GG genotype (OR 3.75, 95% CI 1.06–13.33), while stroke/TIA in men was associated withCD40homozygous major alleles (OR 6.48, 95% CI 1.31–32.0 and OR 2.78, 95% CI 0.78–9.91, respectively). DVT/PE was associated with polymorphism in theGDF15/MIC-1gene (rs1058587) minor allele (OR 3.53, 95% CI 1.30–9.58).

Conclusion.

The gene polymorphisms analyzed were associated with different ATM in RA. TheGDF15/MIC-1gene polymorphism was also associated with RAper se, suggesting a common etiology for RA and ATM.

Genetic predisposition to coronary heart disease and stroke using an additive genetic risk score: a population-based study in Greece

OBJECTIVE

To determine the extent to which the risk for incident coronary heart disease (CHD) increases in relation to a genetic risk score (GRS) that additively integrates the influence of high-risk alleles in nine documented single nucleotide polymorphisms (SNPs) for CHD, and to examine whether this GRS also predicts incident stroke.

METHODS

Genotypes at nine CHD-relevant SNPs were determined in 494 cases of incident CHD, 320 cases of incident stroke and 1345 unaffected controls drawn from the population-based Greek component of the European Prospective Investigation into Cancer and nutrition (EPIC) cohort. An additive GRS was calculated for each study participant by adding one unit for the presence of each high-risk allele multiplied by the estimated effect size of that allele in the discovery samples. Statistical analysis was performed using logistic regression.

RESULTS

The GRS was significantly associated with the incidence of CHD where the odds of CHD incidence in the highest quintile of the GRS were 1.74 times higher (95% confidence interval [CI]=1.25-2.43, p for trend=0.0004), compared to the lowest quintile. With respect to stroke, a weaker and non-significant positive association with GRS was apparent as the odds of stroke incidence in the highest quintile of the GRS were 1.36 times higher (95% CI=0.90-2.06, p for trend=0.188), compared to the lowest quintile.

CONCLUSION

A GRS relying on nine documented "CHD-specific" SNPs is significantly predictive of CHD but it was not found to be statistically significantly associated with incident stroke.

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.

Variants on chromosome 9p21.3 correlated with ANRIL expression contribute to stroke risk and recurrence in a large prospective stroke population

BACKGROUND AND PURPOSE

ANRIL encodes a long antisense noncoding RNA in the INK4 locus. Although ANRIL has been proven to be associated with coronary heart disease, its roles in stroke are inconsistent, and sparse data are available regarding hemorrhagic stroke.

METHODS

A Chinese case-control study was conducted, comprising 1657 cases (724 atherothrombosis, 466 lacunar infarction, and 462 hemorrhagic strokes) and 1664 controls. Stroke patients were prospectively followed-up for a median of 4.5 (range, 0.1-6.0) years. Expression of ANRIL transcripts was examined in 42 human atherosclerotic plaques.

RESULTS

After adjustment for vascular risk factors and correction for multiple comparisons, subjects carrying the GG genotype of rs10757278 had 1.47-fold (95% CI, 1.11-1.89; P=0.05) and 1.60-fold (95% CI, 1.16-2.15; P=0.04) increased risk for atherothrombotic and hemorrhagic strokes, respectively. During the follow-up, 317 recurrent strokes and 301 deaths from all causes were documented. Subjects carrying rs10757278GG had higher risk for stroke recurrence (relative risk [RR],1.56; 95% CI,1.15-2.12; P=0.005) and cardiovascular mortality (RR, 2.0; 95% CI, 1.26-3.18; P=0.003), respectively. Rs10757274 was also associated with stroke risk and recurrence. Family history of stroke further increased the stroke risk by 2.37-fold (95% CI, 1.38-4.06; P=0.01) and recurrent stroke risk by 2.45-fold (95% CI, 1.56-3.86; P<0.0001) respectively, when compared with those carrying none of G-alleles and without family history. Finally, rs10757278 was associated with differential expression of the ANRIL transcripts.

CONCLUSIONS

Our findings indicated that the ANRIL may serve as a novel genetic marker for the risk of atherothrombotic and hemorrhagic stroke and their recurrence.

Genome-wide association study of coronary artery disease in the Japanese

A new understanding of the genetic basis of coronary artery disease (CAD) has recently emerged from genome-wide association (GWA) studies of common single-nucleotide polymorphisms (SNPs), thus far performed mostly in European-descent populations. To identify novel susceptibility gene variants for CAD and confirm those previously identified mostly in populations of European descent, a multistage GWA study was performed in the Japanese. In the discovery phase, we first genotyped 806 cases and 1337 controls with 451 382 SNP markers and subsequently assessed 34 selected SNPs with direct genotyping (541 additional cases) and in silico comparison (964 healthy controls). In the replication phase, involving 3052 cases and 6335 controls, 12 SNPs were tested; CAD association was replicated and/or verified for 4 (of 12) SNPs from 3 loci: near BRAP and ALDH2 on 12q24 (P=1.6 × 10(-34)), HLA-DQB1 on 6p21 (P=4.7 × 10(-7)), and CDKN2A/B on 9p21 (P=6.1 × 10(-16)). On 12q24, we identified the strongest association signal with the strength of association substantially pronounced for a subgroup of myocardial infarction cases (P=1.4 × 10(-40)). On 6p21, an HLA allele, DQB1(*)0604, could show one of the most prominent association signals in an ∼8-Mb interval that encompasses the LTA gene, where an association with myocardial infarction had been reported in another Japanese study. CAD association was also identified at CDKN2A/B, as previously reported in different populations of European descent and Asians. Thus, three loci confirmed in the Japanese GWA study highlight the likely presence of risk alleles with two types of genetic effects - population specific and common - on susceptibility to CAD.

The effect of chromosome 9p21 variants on cardiovascular disease may be modified by dietary intake: evidence from a case/control and a prospective study

BACKGROUND

One of the most robust genetic associations for cardiovascular disease (CVD) is the Chromosome 9p21 region. However, the interaction of this locus with environmental factors has not been extensively explored. We investigated the association of 9p21 with myocardial infarction (MI) in individuals of different ethnicities, and tested for an interaction with environmental factors.

METHODS AND FINDINGS

We genotyped four 9p21 SNPs in 8,114 individuals from the global INTERHEART study. All four variants were associated with MI, with odds ratios (ORs) of 1.18 to 1.20 (1.85×10(-8)≤p≤5.21×10(-7)). A significant interaction (p = 4.0×10(-4)) was observed between rs2383206 and a factor-analysis-derived "prudent" diet pattern score, for which a major component was raw vegetables. An effect of 9p21 on MI was observed in the group with a low prudent diet score (OR = 1.32, p = 6.82×10(-7)), but the effect was diminished in a step-wise fashion in the medium (OR = 1.17, p = 4.9×10(-3)) and high prudent diet scoring groups (OR = 1.02, p = 0.68) (p = 0.014 for difference). We also analyzed data from 19,129 individuals (including 1,014 incident cases of CVD) from the prospective FINRISK study, which used a closely related dietary variable. In this analysis, the 9p21 risk allele demonstrated a larger effect on CVD risk in the groups with diets low or average for fresh vegetables, fruits, and berries (hazard ratio [HR] = 1.22, p = 3.0×10(-4), and HR = 1.35, p = 4.1×10(-3), respectively) compared to the group with high consumption of these foods (HR = 0.96, p = 0.73) (p = 0.0011 for difference). The combination of the least prudent diet and two copies of the risk allele was associated with a 2-fold increase in risk for MI (OR = 1.98, p = 2.11×10(-9)) in the INTERHEART study and a 1.66-fold increase in risk for CVD in the FINRISK study (HR = 1.66, p = 0.0026).

CONCLUSIONS

The risk of MI and CVD conferred by Chromosome 9p21 SNPs appears to be modified by a prudent diet high in raw vegetables and fruits. Please see later in the article for the Editors' Summary.

The association between variants on chromosome 9p21 and inflammatory biomarkers in ethnically diverse women with coronary heart disease: a pilot study

BACKGROUND

The most consistently replicated genetic variants associated with coronary heart disease (CHD) in populations of European descent have been found on chromosome 9p21. Yet there is little known about these associations in ethnic groups of African ancestry. These disease-associated variants are located in a genomic region of unknown function. The purpose of this exploratory study was to examine the allelic frequencies and haplotype structure of single nucleotide polymorphisms (SNPs) for Black and White women with CHD. The authors also sought to explore the relationship between these genetic variants and biomarkers of inflammation.

METHODS

Using polymerase chain reaction amplification, the authors genotyped 8 SNPs in a 58-kilobase region of chromosome 9p21 in a cohort of women with CHD (n = 91). The authors examined the interethnic relationship between the SNPs and four inflammatory biomarkers (C-reactive protein, intercellular adhesion molecule-1, interleukin-6, and tumor necrosis factor-alpha) using analysis of variance (ANOVA).

RESULTS

We found considerable interethnic allelic and haplotype diversity across the 9p21 locus, with only two SNPs in perfect linkage disequilibrium (LD) in both races. A pair of high- and low-risk haplotypes was most common in White women, while about 41% of Blacks carried the risk alleles for three of the eight SNPs the authors examined. The interethnic associations between the SNP genotypes and inflammatory markers were divergent in both direction and magnitude.

CONCLUSIONS

Our results lend support for the importance of ancestry-specific allelic context when examining variants on chromosome 9p21. Additional work is needed to elucidate the genetic contribution to inflammatory biomarkers for diverse racial groups.

Comparative analysis of genome-wide association studies signals for lipids, diabetes, and coronary heart disease: Cardiovascular Biomarker Genetics Collaboration

Aims

To evaluate the associations of emergent genome-wide-association study-derived coronary heart disease (CHD)-associated single nucleotide polymorphisms (SNPs) with established and emerging risk factors, and the association of genome-wide-association study-derived lipid-associated SNPs with other risk factors and CHD events.

Methods and results

Using two case–control studies, three cross-sectional, and seven prospective studies with up to 25 000 individuals and 5794 CHD events we evaluated associations of 34 genome-wide-association study-identified SNPs with CHD risk and 16 CHD-associated risk factors or biomarkers. The Ch9p21 SNPs rs1333049 (OR 1.17; 95% confidence limits 1.11–1.24) and rs10757274 (OR 1.17; 1.09–1.26), MIA3 rs17465637 (OR 1.10; 1.04–1.15), Ch2q36 rs2943634 (OR 1.08; 1.03–1.14), APC rs383830 (OR 1.10; 1.02, 1.18), MTHFD1L rs6922269 (OR 1.10; 1.03, 1.16), CXCL12 rs501120 (OR 1.12; 1.04, 1.20), and SMAD3 rs17228212 (OR 1.11; 1.05, 1.17) were all associated with CHD risk, but not with the CHD biomarkers and risk factors measured. Among the 20 blood lipid-related SNPs, LPL rs17411031 was associated with a lower risk of CHD (OR 0.91; 0.84–0.97), an increase in Apolipoprotein AI and HDL-cholesterol, and reduced triglycerides. SORT1 rs599839 was associated with CHD risk (OR 1.20; 1.15–1.26) as well as total- and LDL-cholesterol, and apolipoprotein B. ANGPTL3 rs12042319 was associated with CHD risk (OR 1.11; 1.03, 1.19), total- and LDL-cholesterol, triglycerides, and interleukin-6.

Conclusion

Several SNPs predicting CHD events appear to involve pathways not currently indexed by the established or emerging risk factors; others involved changes in blood lipids including triglycerides or HDL-cholesterol as well as LDL-cholesterol. The overlapping association of SNPs with multiple risk factors and biomarkers supports the existence of shared points of regulation for these phenotypes.

Implications of discoveries from genome-wide association studies in current cardiovascular practice

Genome-wide association studies (GWAS) have identified several genetic variants associated with coronary heart disease (CHD), and variations in plasma lipoproteins and blood pressure (BP). Loci corresponding to CDKN2A/CDKN2B/ANRIL, MTHFD1L, CELSR2, PSRC1 and SORT1 genes have been associated with CHD, and TMEM57, DOCK7, CELSR2, APOB, ABCG5, HMGCR, TRIB1, FADS2/S3, LDLR, NCAN and TOMM40-APOE with total cholesterol. Similarly, CELSR2-PSRC1-SORT1, PCSK9, APOB, HMGCR, NCAN-CILP2-PBX4, LDLR, TOMM40-APOE, and APOC1-APOE are associated with variations in low-density lipoprotein cholesterol levels. Altogether, forty, forty three and twenty loci have been associated with high-density lipoprotein cholesterol, triglycerides and BP phenotypes, respectively. Some of these identified loci are common for all the traits, some do not map to functional genes, and some are located in genes that encode for proteins not previously known to be involved in the biological pathway of the trait. GWAS have been successful at identifying new and unexpected genetic loci common to diseases and traits, thus rapidly providing key novel insights into disease biology. Since genotype information is fixed, with minimum biological variability, it is useful in early life risk prediction. However, these variants explain only a small proportion of the observed variance of these traits. Therefore, the utility of genetic determinants in assessing risk at later stages of life has limited immediate clinical impact. The future application of genetic screening will be in identifying risk groups early in life to direct targeted preventive measures.

Detection of single nucleotide polymorphism using tension-dependent stochastic behavior of a single-molecule template

Single nucleotide polymorphism (SNP) is the most common genetic variation among individuals. The association of SNP with individual's response to pathogens, phenotypic variations, and gene functions emphasizes the importance of sensitive and reliable SNP detection for biomedical diagnosis and therapy. To increase sensitivity, most approaches employ amplification steps, such as PCR, to generate detectable signals that are usually ensemble-averaged. Introduction of amplification steps increases the complexity of a system, whereas ensemble averaging of signals often suffers from background interference. Here, we have exploited the stochastic behavior of a single-molecule probe to recognize SNP sequence in a microfluidic platform using a laser-tweezers instrument. The detection relies on on-off mechanical signals that provide little background interference and high specificity between wild type and SNP sequences. The microfluidic setting allows multiplex sensing and in situ recycling of the SNP probe. As a proof-of-concept, we have detected as low as 100 pM of an SNP target associated with coronary heart diseases within half an hour without any amplification steps. The mechanical signal permits the detection of single mutations involving either G/C or A/T pairs. We anticipate this system has the capacity to function as a highly sensitive generic biosensor after incorporation of a specific recognition element, such as an aptamer for example.

[Genetic variants, cardiovascular risk and genome-wide association studies]

Genome-wide association studies have shown an association between single nucleotide polymorphisms (SNPs) and coronary artery disease and myocardial infarction in new chromosomal regions: 1p13.1, 2q36.3, 9p21 and 10q11.21. The SNPs from the 9p21 region constitute a risk haplotype due to the strong linkage disequilibrium in this area. These SNPs have been extensively replicated in several European and Asian populations, and are associated with other pathologies such as abdominal aortic and intracranial aneurysms, and with intermediate phenotypes such as arterial stiffness and coronary calcium. The risk haplotype of 9p21 is located in a region without annotated genes, near CDKN2A and CDKN2B, known tumor suppressor genes encoding for inhibitors of cell cycle kinases. In the remaining regions the SNPs are located in genes with known roles in atherosclerosis as well as others with new roles. It has been shown that the incorporation of genetic information in the form of SNPs slightly improves the prediction of long-term cardiovascular risk estimated by the Framingham function, allowing the reclassification of individuals into more precise categories. Gene expression studies have found that expression levels of CDKN2A/CDKN2B/ANRIL are co-regulated and associated with the risk haplotype and atherosclerosis severity.

The relationship between polymorphisms on chromosome 9p21 and age of onset of coronary heart disease in black and white women

AIM

Genome-wide association studies have identified variants on chromosome 9p21 that are associated with coronary heart disease (CHD). The relationship between these variants and the age of onset of CHD is less clear. The aim of this study was to examine the allelic frequencies and haplotype structure of eight single-nucleotide polymorphisms (SNPs) on chromosome 9p21 in ethnically diverse women. We also explored the relationship between 9p21 SNPs and the age of CHD onset.

RESULTS

There was considerable interethnic allelic and haplotype diversity across the 9p21 locus with only two SNPs (rs10757274 and rs4977574) in perfect linkage disequilibrium in both races, and only a small proportion of the haplotypes shared between the racial groups. With the exception of rs1333040, whites with at least one copy of the 9p21 SNP risk alleles were found to have CHD from 1.45 (rs10116277) to 4.77 (rs2383206) years earlier than those with the wild-type alleles. Blacks carrying at least one copy of the risk allele (92%) for rs1333040 had a CHD age of onset that was 6.5 years earlier than those with the wild-type alleles.

CONCLUSIONS

Different variants on chromosome 9p21 may influence CHD age of onset in whites and blacks.

Extended evidence for association between the melanoma inhibitory activity 3 gene and myocardial infarction

In a genome-wide scan, isolated single nucleotide polymorphisms (SNPs), including rs17465637, in the melanoma inhibitory activity 3 gene (MIA3) on chromosome 1 were identified to be associated with coronary artery disease and myocardial infarction (MI). Because the role of common variation at the MIA3 locus has not yet been investigated, the aim of this case-control study was to determine the impact of haplotype-tagging SNPs and haplotypes in the MIA3 region on the risk of MI. In a set of nine haplotype-tagging SNPs, rs17465637, but none of the other SNPs, was associated with MI. After adjustments were made for age, gender, history of arterial hypertension, history of hypercholesterolaemia, current cigarette smoking and diabetes mellitus, multiple logistic regression analyses showed an increased risk in the carriers of one or two C alleles [adjusted odds ratio (OR) 1.17, 95% confidence interval (CI) 1.04-1.32, and 1.37, 95% CI 1.08-1.74, respectively]. Nine common haplotypes (frequency >1%) were established across the MIA3 region. Two of the haplotypes were associated with an increased risk of MI: the frequent (48%) TGACCAAAG haplotype and the rare (2%) CGACCAAAG haplotype (adjusted OR 1.102, 95% CI 1.002-1.212, and 1.574, 95% CI 1.077-2.298, respectively). Showing association between rs17465637 and MI, this work was consistent with results from the original detection study and most prior replication studies addressing this issue. In addition to correspond with such isolated evidence of association with MI, the present study identified specific haplotypes capturing the risk-related variation in the entire MIA3 region.

Genetic variation in LPAL2, LPA, and PLG predicts plasma lipoprotein(a) level and carotid artery disease risk

BACKGROUND AND PURPOSE

lipoprotein(a) [Lp(a)] level is an established risk factor for coronary artery disease and has been implicated in carotid artery disease (CAAD). The relationship between genetic variation in the LPA gene region and CAAD risk remains unknown.

METHODS

we genotyped single nucleotide polymorphisms (SNPs) in the LPAL2, LPA, and PLG regions in 530 individuals with severe CAAD and 770 controls and kringle IV type 2 (KIV2) repeat length in a subset of 90 individuals.

RESULTS

nine SNPs collectively accounted for 30% of the variance in Lp(a) level. Six SNPs were associated with Lp(a) level after accounting for KIV2 copy number, and the dominant KIV2 allele combined with these markers explained 60% of the variance in Lp(a) level. Five SNPs, including rs10455872, which had an odds ratio of 2.1 per minor allele and haplotypes formed by rs10455872, rs6919346, and rs3123629, were significant predictors of CAAD. After accounting for Lp(a) level, all evidence of CAAD-genotype association in the LPA region was eliminated.

CONCLUSIONS

LPA region SNPs capture some but not all of the effect of KIV2 repeat length on Lp(a) level. There are associations between LPA region SNPs and CAAD that appear to be attributable to effects on Lp(a) level.

Combined effect of inflammatory gene polymorphisms and the risk of ischemic stroke in a prospective cohort of subjects with type 2 diabetes: a Go-DARTS study

OBJECTIVE

We have previously observed that genetic profiles determined by the combination of five functionally significant single nucleotide polymorphisms (SNPs) (rs1800795, rs5498, rs5361, rs1024611, and rs679620) of genes encoding prototypical inflammatory molecules are associated with history of ischemic stroke. Here we tested the ability of this multigenic model to predict stroke risk in a large population-based prospective cohort of subjects with type 2 diabetes.

RESEARCH DESIGN AND METHODS

This study was conducted using a prospective cohort of individuals with type 2 diabetes participating in the Go-DARTS (Genetics of Diabetes Audit and Research in Tayside Scotland) study, which includes genetic and clinical information of patients with diabetes within the Tayside region of Scotland, U.K. The above-mentioned inflammatory SNPs were investigated in 2,182 Go-DARTS participants. We created an inflammatory risk score (IRS), ranging from 0 to 5, according to the number of "at-risk" genotypes concomitantly carried by a given individual. The primary outcome was the occurrence of fatal or nonfatal stroke of any kind. Mean follow-up time was 6.2 ± 1.1 years.

RESULTS

The incidence of stroke increased according to the IRS. The IRS was significantly and independently associated with increased stroke risk after adjustment for other conventional risk factors (hazard ratio 1.34 [95% CI 1.1-1.7]; P = 0.009). The highest hazard ratio for stroke was found in subjects concomitantly carrying > 3 proinflammatory variations and in subjects without previous cardiovascular diseases.

CONCLUSIONS

This large prospective cohort study provides evidence that SNPs of genes encoding prototypical inflammatory molecules may be used to create multigenic models that predict stroke risk in subjects with type 2 diabetes.

Translating genomic analyses into improved management of coronary artery disease

Human genetic variation can modulate pathophysiologic processes that alter susceptibility to complex disease. Recent genomic analyses have sought to identify how common genetic variation alters susceptibility to coronary artery disease (CAD). From genome-wide association studies (GWAS), common genetic variants in several novel chromosomal loci have been associated with CAD. GWAS identified the 9p21 locus as the strongest independent genetic CAD risk factor, along with 11 additional loci that harbor common genetic variants associated with increased CAD risk. A thorough understanding of human genetic variation and genomic analyses will be crucial to understand how GWAS-identified loci increase susceptibility to CAD. This article outlines the relevance of genetic variation in the elucidation of novel CAD risk factors and the clinical utility of genetic variants in the management and treatment of CAD.

Sort1, encoded by the cardiovascular risk locus 1p13.3, is a regulator of hepatic lipoprotein export

Recent genome-wide association studies (GWAS) have revealed strong association of hypercholesterolemia and myocardial infarction with SNPs on human chromosome 1p13.3. This locus covers three genes: SORT1, CELSR2, and PSRC1. We demonstrate that sortilin, encoded by SORT1, is an intracellular sorting receptor for apolipoprotein (apo) B100. It interacts with apoB100 in the Golgi and facilitates the formation and hepatic export of apoB100-containing lipoproteins, thereby regulating plasma low-density lipoprotein (LDL) cholesterol. Absence of sortilin in gene-targeted mice reduces secretion of lipoproteins from the liver and ameliorates hypercholesterolemia and atherosclerotic lesion formation in LDL receptor-deficient animals. In contrast, sortilin overexpression stimulates hepatic release of lipoproteins and increases plasma LDL levels. Our data have uncovered a regulatory pathway in hepatic lipoprotein export and suggest a molecular explanation for the cardiovascular risk being associated with 1p13.3.

Plasma bilirubin and UGT1A1*28 are not protective factors against first-time myocardial infarction in a prospective, nested case-referent setting

BACKGROUND

Bilirubin, an effective antioxidant, shows a large variation in levels between individuals and has been positively associated with reduced cardiovascular disease risk. A major reason for the variability is a common promoter polymorphism, UGT1A1*28, which reduces the transcription of the enzyme that conjugates bilirubin, UDP-glucuronosyltransferase 1A1. The aim of the study was to evaluate a possible protective effect of plasma bilirubin and the UGT1A1*28 polymorphism against myocardial infarction in a prospective case-referent setting.

METHODS AND RESULTS

Subjects (n=618) with a first-ever myocardial infarction (median event age, 60.5 years; median lag time, 3.5 years) and 1184 matched referents were studied. Plasma bilirubin was lower in cases versus referents. Despite a strong gene-dosage effect on bilirubin levels in both cases and referents, the UGT1A1*28 polymorphism did not influence the risk of myocardial infarction. Among multiple other variables, serum iron showed one of the strongest associations with bilirubin levels.

CONCLUSIONS

We found no evidence for a protective effect of the UGT1A1*28 polymorphism against myocardial infarction and consequently neither for bilirubin. The lower bilirubin levels in cases might be caused by decreased production, increased degradation, or increased elimination.