A meta-analysis of candidate gene polymorphisms and ischemic stroke in 6 study populations: association of lymphotoxin-alpha in nonhypertensive patients

Association of TGFB1 rs1800469 and BCMO1 rs6564851 with coronary heart disease and IL1B rs16944 with all-cause mortality in men from the Northern Ireland PRIME study

Background

Historically, high levels of morbidity and mortality have been associated with cardiovascular disease in the Northern Ireland population. Previously reported associations between single nucleotide polymorphisms (SNPs) and cardiovascular disease within other populations have not always been consistent.

Objective

To investigate associations between 33 SNPs with fatal or non-fatal incident coronary heart disease (CHD) events and all-cause mortality in the Northern Irish participants of the Prospective Epidemiological Study of Myocardial Infarction (PRIME).

Method

Phase 2 of the PRIME study prospectively evaluated 2,010 men aged 58–74 years in Northern Ireland for more than 10 years for incident CHD events (myocardial infarction, percutaneous coronary intervention, coronary artery bypass, and cardiac death) and more than 15 years for all-cause mortality. SNPs previously reported in association with cardiovascular outcomes were evaluated against incident CHD events and all-cause mortality using Cox’s proportional hazards models adjusted for established cardiovascular disease risk factors.

Results

During the follow-up period, 177 incident CHD events were recorded, and 821 men died. Both BCMO1 rs6564851 (Hazard ratio [HR] = 0.76; 95% confidence intervals [CI]: 0.60–0.96; P = 0.02) and TGFB1 rs1800469 (HR = 1.30; CI: 1.02–1.65; P = 0.04) were significantly associated with incident CHD events in adjusted models. Only IL1B rs16944 was significantly associated with all-cause mortality (HR = 1.18; CI: 1.05–1.33; P = 0.005). No associations remained significant following Bonferonni correction for multiple testing.

Conclusion

We report a novel association between BCMO1 rs6564851 and risk of incident CHD events. In addition, TGFB1 rs1800469 and IL1B rs16944 were associated with the risk of incident CHD events and all-cause mortality outcomes respectively, supporting previously reported associations.

Apolipoprotein E ε4 Polymorphism as a Risk Factor for Ischemic Stroke: A Systematic Review and Meta-Analysis

Introduction

Rising studies indicate that the apolipoprotein E (APOE) gene is related to the susceptibility of ischemic stroke (IS). However, certain consensus is limited by the lack of a large sample size of researches. This meta-analysis was performed to explore the potential association between the APOE gene and IS.

Methods

To identify relevant case control studies in English publications by October 2020, we searched PubMed, Embase, Web of Science, and the Cochrane Library. Pooled odds ratios (ORs) with fixed- or random-effect models and corresponding 95% confidence intervals (CIs) were calculated to analyze potential associations.

Results

A total of 55 researches from 32 countries containing 12207 IS cases and 27742 controls were included. The association between APOE gene ε4 mutation and IS was confirmed (ε4 vs. ε3 allele: pooled OR = 1.374, 95% CI, 1.214-1.556; ε2/ε4 vs. ε3/ε3: pooled OR = 1.233, 95% CI, 1.056-1.440; ε3/ε4 vs. ε3/ε3: pooled OR = 1.340, 95% CI, 1.165-1.542; ε4/ε4 vs. ε3/ε3: pooled OR = 1.833, 95% CI, 1.542-2.179; and APOE ε4 carriers vs. non-ε4 carriers: pooled OR = 1.377; 95% CI, 1.203-1.576). Interestingly, APOE ε4 mutation showed a dose-response correlation with IS risk (ε4/ε4 vs. ε2/ε4: pooled OR = 1.625; 95% CI, 1.281-2.060; ε4/ε4 vs. ε3/ε4: pooled OR = 1.301; 95% CI, 1.077-1.571). Similar conclusions were drawn in the small artery disease (SAD) subtype, but not in large artery atherosclerosis (LAA) or in cardioaortic embolism (CE), by subgroup analysis.

Conclusions

These observations reveal that specific APOE ε4 mutation was significantly associated with the risk of IS in a dose-dependent manner, while APOE ε4 mutation was related to SAD subtype onset without a cumulative effect.

Variants in CDHR3, CACNAC1, and LTA Genes Predisposing Sensitivity and Response to Warfarin in Patients with Cardiovascular Disease

Introduction

Warfarin has been in use for more than 60 years; however, it has serious side effects including major bleeding. The high interpatient variability in the required dose impacts the sensitivity and responsiveness to warfarin in different patients. This study aims to assess the influence of CDHR3, CACNAC1, and LTA gene polymorphisms on the variability of warfarin dose requirements and susceptibility to coronary heart disease in the Jordanian population.

Methods

This study was conducted in the anti-coagulation clinic in Queen Alia Heart Institute in Amman, with 212 patients in total. Three SNPs were genotyped within CDHR3 (rs10270308), CACNAC1 (rs216013), and LTA (rs1041981) genes.

Results

Our findings revealed that patients with LTA polymorphism are more prone to warfarin sensitivity than others. Furthermore, carriers of the LTA polymorphism needed a lower initial dose of warfarin and are associated with less variation in doses required to achieve target INR.

Conclusion

The current study could help in understanding the role of genetic variability in warfarin dosing and matching patients to different treatment options. Clinical applications of these findings for warfarin treatment may also contribute to improving the efficacy and safety of warfarin treatment in Jordanian patients with cardiovascular disease.

The effect of β3-adrenoceptor gene polymorphisms on lower urinary tract function in males

PURPOSE

To clarify the role of Trp64Arg polymorphisms of the gene encoding the β₃-adrenoceptor for lower urinary tract function in males, the present study investigated the association between the Trp64Arg polymorphisms and lower urinary tract symptoms (LUTS) and function.

METHODS

This prospective observational study included patients who underwent robot-assisted radical prostatectomy. Before surgery, blood samples were collected, and analyses of β₃-adrenoceptor gene polymorphism were performed using the real-time polymerase chain reaction. The present cohort was divided into patients with wild type (Trp64Trp) and with variant type (Trp64Arg + Arg64Arg), and LUTS and lower urinary tract function before surgery were compared between them.

RESULTS

Wild type was found in 247 patients, with variant type in 129. There were no significant differences in LUTS between the two groups. Residual urine volume (PVR) (wild type: variant type = 47 ± 53 mL: 58 ± 77 mL, P = 0.04) and voiding time on uroflowmetry (wild type: variant type = 29 ± 15 s: 33 ± 17 s, P = 0.04) were significantly increased in the variant type.

CONCLUSION

The Trp64Arg variant of the β₃-adrenoceptor gene significantly increased PVR and voiding time in men. However, it was not significantly associated with the emergence of LUTS. Thus, since the effect of β₃-adrenoceptor gene polymorphisms on the genitourinary organs might be weak, whether men possess the Trp64Arg variant of the β₃-adrenoceptor gene might not critically affect urinary quality of life, but modestly affect the lower urinary tract function.

[Association of rs3025058 polymorphism with the development of stroke in patients with cardiovascular pathology]

AIM

To study the association of single-nucleotide polymorphismrs3025058(5а/6а) with the development of stroke in patients of the East Siberian population with cardiovascular pathology and risk factors for its development.

MATERIALS AND METHODS

The study involved 260 patients with stroke (age [57.0; 51.062.0]) and 272 patients of the control group (age [55.0; 51.062.0]). Among the patients who underwent stroke, 157 men and 103 women. The control group included 170 men and 102 women. The examination of the main group included: collection of complaints, anamnesis, clinical examination, computed tomography of the brain, electrocardiography, echocardioscopy, ultrasound duplex scanning of the extracranial brachiocephalic arteries, 24-hour monitoring of blood pressure and heart rate, analysis of the blood coagulation system. The patients of the main group had the following cardiovascular pathology and risk factors: arterial hypertension, paroxysmal supraventricular tachycardias, dyslipidemia, atherosclerosis of extracranial brachiocephalic arteries, disorders of the hemostasis system. The control group was examined within the framework of the international project HAPIEE. Molecular genetic research was carried out by real-time PCR. Statistical processing of the material was carried out using the Statistica for Windows 7.0, Excel and SPSS 22 application software.

RESULTS

The study established statistically significant associations between the 5a/5a genotype and the 5a allele and stroke in the general group of patients, as well as in the subgroup of men, subgroups of patients with extracranial brachiocephalic arteries atherosclerosis and dyslipidemia. In the subgroup of patients with cardiac arrhythmias, statistically significant results were obtained only for allele 5a, and in the subgroup of women with stroke, subgroups of patients with arterial hypertension and hypercoagulation, no significant associations ofrs3025058(5a/6a) polymorphism with stroke were found.

CONCLUSION

Genotype 5a/5a and allele 5a of the single-nucleotide polymorphismrs3025058(5а/6а) increase the risk of stroke in individuals from the East Siberian population, including those in the presence of such risk factors as extracranial brachiocephalic arteries atherosclerosis and dyslipidemia.

Association of lymphotoxin-alpha gene polymorphisms (rs909253, rs1800683 and rs2229094) and risk of large-artery atherosclerosis stroke in Iranian population

BACKGROUND

Lymphotoxin-alpha (LTA), a proinflammatory cytokine, is significantly associated with the progression of atherosclerosis as an independent hazard factor for stroke. According to new genetic studies, polymorphisms in the LTA gene that influence its expression or biological function may play a role in the progress of stroke; thus, the present case-control study investigated LTA gene polymorphisms (rs909253, rs1800683 and rs2229094) and the risk of large artery atherosclerosis stroke (LAA) in an Iranian population.

METHODS

For 211 large artery atherosclerosis patients and 186 ischemic stroke-free controls, genotypes were determined using the tetra-primer amplification-refractory mutation system polymerase chain reaction method. Linkage disequilibrium and estimated haplotypes were analyzed using SNP Analyzer 2 software. The strength of the link between LTA gene polymorphisms (rs1800683, rs909253, and rs2229094) and the risk of stroke was determined using conditional logistic regression.

RESULTS

Analysis revealed that the patterns of the rs1800683, rs909253 and rs2229094 genotypes showed no significant difference between the LAA and control group, although the distribution of the GAT (rs1800683G, rs909253A and rs2229094T) haplotype was significantly higher in the control group (odds ratio = 0.707, 95% confidence interval = 0.53-0.942, p = 0.0355).

CONCLUSIONS

Our results indicate that the GAT haplotype in LTA gene is associated with a decreased risk of LAA incidence in a northeastern Iranian population.

Association between lipoprotein(a) (Lp(a)) levels and Lp(a) genetic variants with coronary artery calcification

Background

To examine the association between lipoprotein(a) (Lp(a)) levels, LPA (rs10455872 and rs3798220) and IL1F9 (rs13415097) single nucleotide polymorphisms (SNPs) with coronary artery calcification (CAC), an important predictor for coronary artery disease (CAD).

Methods

We used data from 3799 (mean age ± SD: 59.0 ± 7.7 years, 47.1% men) Heinz Nixdorf Recall study participants. We applied linear regression models to explore the relation between the log-transformed Lp(a) levels and LPA and IL1F9 SNPs with log_e (CAC + 1). The association between the SNPs and log-transformed Lp(a) levels was further assessed using linear regression. The models were adjusted for age and sex (Model 1) and additionally for Lp(a) levels (Model 2).

Results

We observed a statistically significant association between log-transformed Lp(a) levels and CAC (Model 1: beta per log-unit increase in Lp(a) levels = 0.11; 95% confidence interval [95% CI] [0.04; 0.18], p = 0.002). Furthermore, the LPA SNP rs10455872 showed a statistically significant association with CAC (Model 1: beta per allele = 0.37 [0.14; 0.61], p = 0.002). The association between rs10455872 and CAC was attenuated after adjustment for Lp(a) levels (Model 2: beta per allele = 0.26 [− 0.01; 0.53], p = 0.06). Both LPA SNPs also showed a statistically significant association with Lp(a) levels (Model 1: beta_rs10455872 per allele: 1.56 [1.46; 1.65], p < 0.0001 and beta_rs3798220 per allele: 1.51 [1.33; 1.69], p < 0.0001)). The Mendelian randomization analysis showed that Lp(a) is a causal risk factor for CAC (estimate per log-unit increase in Lp(a) levels (95% CI), p: 0.27 [0.11; 0.44], p = 0.001). The IL1F9 SNP did not show any statistically significant association with Lp(a) levels or with CAC.

Conclusions

We provide evidence for the association of LPA rs10455872 with higher levels of Lp(a) and CAC in our study. The results of our study suggest that rs10455872, mediated by Lp(a) levels, might play a role in promoting the development of atherosclerosis leading to cardiovascular disease events.

Genetic Factors of Nitric Oxide's System in Psychoneurologic Disorders

According to the recent data, nitric oxide (NO) is a chemical messenger that mediates functions such as vasodilation and neurotransmission, as well as displaying antimicrobial and antitumoral activities. NO has been implicated in the neurotoxicity associated with stroke and neurodegenerative diseases; neural regulation of smooth muscle, including peristalsis; and penile erections. We searched for full-text English publications from the past 15 years in Pubmed and SNPedia databases using keywords and combined word searches (nitric oxide, single nucleotide variants, single nucleotide polymorphisms, genes). In addition, earlier publications of historical interest were included in the review. In our review, we have summarized information regarding all NOS1, NOS2, NOS3, and NOS1AP single nucleotide variants (SNVs) involved in the development of mental disorders and neurological diseases/conditions. The results of the studies we have discussed in this review are contradictory, which might be due to different designs of the studies, small sample sizes in some of them, and different social and geographical characteristics. However, the contribution of genetic and environmental factors has been understudied, which makes this issue increasingly important for researchers as the understanding of these mechanisms can support a search for new approaches to pathogenetic and disease-modifying treatment.

The association of MTHFR C677T variant with increased risk of ischemic stroke in the elderly population: a meta-analysis of observational studies

Background

C677T point mutation in methylenetetrahydrofolate reductase (MTHFR) gene have been found to be associated with ischemic stroke in general population, while the results seem inconsistent. We aim to assess the association between variant MTHFR C677T variant and increased risk of ischemic stroke and focus on the elderly population.

Methods

We searched PubMed, Embase, Cochrane Library, and Web of Science for eligible studies. Odds ratios (ORs) were calculated with the two-tailed 95% confidence intervals (CIs) by using a random effects model to evaluate any possible association. Among the Chinese and non-Chinese populations, we conducted a subgroup analysis.

Results

The electronic database search yielded 1,358 citations as of December 2017; finally, nine case-control studies involving 3,337 subjects fulfilled our eligibility criteria for inclusion in the study. The pooled results showed that MTHFR C677T variant increased the risk of ischemic stroke (OR = 1.23, 95%CI 1.06–1.43, P = 0.0067 for CT + TT vs. CC; OR = 1.18, 95%CI 1.01–1.38, P = 0.0333 for CT vs. CC; OR = 1.41, 95%CI 1.14–1.75, P = 0.0016 for TT vs. CC; OR = 1.27, 95%CI 1.05–1.54, P = 0.0145 for TT vs. CC + CT; OR = 1.18, 95%CI 1.06–1.31, P = 0.0023 for T-allele vs. C-allele). Further subgroup analyses in the Chinese population indicated that MTHFR C677T variant was associated with a higher risk of ischemic stroke.

Conclusion

Our findings showed that T-allele increases risk for stroke in the pooled sample. This association was statistically significant in the Chinese cohorts and showed a similar trend in the non-Chinese cohorts. (Word count: 237).

The Association of SNPs Located in the CDKN2B-AS1 and LPA Genes With Carotid Artery Stenosis and Atherogenic Stroke

Introduction: The aim of this project was to assess the prevalence of four selected SNPs rs4977574 and rs7857345 (CDKN2B-AS1 gene) and rs3798220 and rs10455872 polymorphisms (the LPA gene) in the subpopulation of patients with symptomatic and asymptomatic carotid stenosis.

Material and Methods: This study included 623 individuals (244 patients with symptomatic carotid artery stenosis, 176 patients with asymptomatic carotid artery stenosis and 203 healthy people. All the participants underwent neurological examination, duplex Doppler ultrasound examination and molecular procedures.

Results: In the first part of the analysis the assiociation of SNPs with stroke/TIA was investigated. The association was seen in symptomatic vs. control group for two SNPs: rs4977574 and rs7857345 (CDKN2B-AS1 gene); genotype distributions for rs4977574 and rs7857345 showed the statistically significant differences between patients and controls (p = 0.043 and 0.017, respectively). No association was observed for rs3798220 and rs10455872 located in the LPA gene. There were statistically significant differences between asymptomatic patients vs. control group in genotype distribution for the SNPs located in CDKN2B-AS1: rs4977574 and rs7857345 (p = 0.031 and 0.0099, respectively); and for the rs3798220 (LPA gene; p = 0.003); however, statistically significant differences did not occur for the rs10455872 polymorphism located in the LPA gene. In the next part of the evaluation, a comparison between symptomatic and asymptomatic patients was performed. Significant differences in genotype distribution were seen only for the rs3798220 polymorphism located in the LPA gene (p = 0.0015). The analysis of the prevalence of the polymorphisms in the total group (symptomatic and asymptomatic) patients in comparison with the control group showed significant differences for three polymorphisms: rs4977574 and rs7857345 (CDKN2B-AS1 gene; p = 0.015 and 0.0046, respectively) and rs3798220 (LPA gene, p = 0.044).

Conclusions: The present research on the carotid artery stenosis patient cohort suggests the significant association between the rs4977574, rs7857345 and rs3798220 polymorphisms and carotid artery stenosis as well as between the rs4977574 and rs7857345 polymorphisms and atherogenic stroke. The rs4977574 and rs7857345 polymorphisms in patients with carotid artery stenosis appear to affect a person's susceptibility to atherogenic brain ischemia. Our results need to be replicated in future studies.

Association of PAI-1 4G/5G Polymorphism with Ischemic Stroke in Chinese Patients with Type 2 Diabetes Mellitus

BACKGROUND/AIM

To investigate the association of the genetic polymorphisms of the plasminogen activator inhibitor type 1 (PAI-1) gene with the risk of ischemic stroke (IS) in subjects with type 2 diabetes mellitus (T2DM).

MATERIALS AND METHODS

Using a case-control study design, 175 individuals with T2D and IS were enrolled in the case group and 125 patients with T2D without IS were enrolled as controls. The clinical characteristics of the groups were compared, and genotypes were determined by direct DNA sequencing.

RESULTS

Male and hypertensive subjects were higher in the IS group (p = 0.002 and 0.014, respectively). High-density lipoprotein (HDL) and apolipoprotein A1 (APOA1) were lower in the IS group (p = 0.011 and 0.025, respectively); hemoglobin A1c (HbA1c), total homocysteine (tHcy), and FT4 levels were higher in the IS group (p = 0.022, 0.003, and 0.008, respectively). The 4G/4G, 4G/5G, and 5G/5G genotype frequencies were 40.0%, 46.4%, and 13.6% in the control group versus 31.4%, 52.0% and 16.6% in the IS group, respectively. Hypertension (odds ratio [OR] = 1.953, p = 0.020), tHcy (OR = 1.059, p = 0.029), thyroid-stimulating hormone (OR = 0.876, p = 0.039), and the PAI-1 genotype dominant allele model (OR = 1.748, p = 0.047) were associated with IS by multivariate analysis.

CONCLUSION

The PAI-1 genotype dominant allele model was a risk factor for IS in patients with T2DM of Jinan, China.

The combined effects of cardiovascular disease related SNPs on ischemic stroke

PURPOSE

Previous studies have revealed multiple common variants associated with known risk factors for cardiovascular disease (CVD). Ischemic stroke (IS) and CVD share several risk factors with each having substantial heritability. We aimed to generate a multi-locus genetic risk score (GRS) for IS based on CVD related SNPs to evaluate their combined effects on IS.

METHODS

A total of 851 patients and 977 controls were selected from Beijing, Tianjin, Shandong, Shanxi, Shaanxi and Heilongjiang communities. The candidate genes were genotyped by PCR-hybridization. Information about demographic factors, history of disease (such as hypertension), and lifestyle was obtained using structured questionnaires. A GRS model weighted by the absolute value of regression coefficient β was established to comprehensively assess the association between candidate SNPs and IS. Using the area under the receiver operating characteristic curve (AUC) to evaluate the value of GRS on predicting IS.

RESULTS

The GRS of cases was 2.87 ± 0.28, which was significantly higher than controls' GRS (2.78 ± 0.30) (P < 0.000). With the increase of the GRS, the risk of IS became higher (P_trend < 0.000). Subjects in the top quartile of the GRS had about 1.9-fold increased risk of IS compared with subjects in the lowest quartile (OR _adjusted = 1.880, 95%CI = 1.442-2.452, P < 0.000). The AUC = 0.580, P < 0.000.

CONCLUSION

13 CVD related SNPs had combined effects on IS. The GRS of cases was significantly higher than controls' GRS. As the GRS increased, the risk of IS increased. The GRS model has some value for the prediction of IS.

The Methylenetetrahydrofolate Reductase C677T (rs1801133) and Apolipoprotein A5-1131T>C (rs662799) Polymorphisms, and Anemia Are Independent Risk Factors for Ischemic Stroke

BACKGROUND

Although there is adequate knowledge as to the role of traditional cardiovascular risk factors on stroke incidence, knowledge of other risk factors, particularly genetic ones, is still incomplete.

METHODS

To assess the participation of some polymorphisms, along with other modifiable risk factors, a case-control study was conducted. A total of 253 cases were identified in the emergency room of a general regional hospital, with a clinical trait of stroke confirmed by a skull computerized axial tomography scan. In the surgery ward, 253 controls were identified, gender and age (±5 years) matched. Biochemical parameters were measured, and 4 polymorphisms were genotyped by polymerase chain reaction, rs1801133 (methylenetetrahydrofolate reductase [MTHFR]), rs1498373 (dimethylarginine dimethylaminohydrolase type 1 [DDAH1]), rs662799 (apolipoprotein A5 [APOA5]), and rs1799983 (endothelial nitric oxide). Odds ratios were estimated to assess the strength of association, with 95% confidence intervals, both in a matched case-control analysis and in a conditional regression analysis.

RESULTS

Cases had higher mean blood pressure and triglycerides and lower hemoglobin levels. Heterozygous and homozygous subjects to the rs1801133 variant of the MTHFR gene had a 3-fold higher risk of stroke. In the dominant model, those with the polymorphism rs662799 of the promoter region for APOA5 had twice the risk of stroke. Anemia increased the risk of stroke 4-fold.

CONCLUSIONS

Polymorphisms of the genes MTHFR (rs1801133) and APOA5 (rs662799), as well as anemia, are independent risk factors for stroke in Mexicans, together with traditional cardiovascular risk factors such as high triglycerides and high blood pressure.

A meta-analysis of PDE-gene polymorphism and cerebral infarction risk

Previous studies identified that phosphodiesterase 4D (PDE4D) gene polymorphism might be associated with cerebral infarction or ischemic stroke, and hemorrhagic stroke in human populations. However, as yet, no meta-analysis has revealed any detailed association. We retrospectively reviewed studies regarding the relationship of PDE4D gene polymorphism with ischemic stroke (IS) published during the period January 2003 to September 2012. According to the inclusion criteria, 9 of 105 initial studies were included in the subsequent analysis. The PubMed, Embase and CNKI of China were searched to identify the relevant studies. A total of 186 young patients with IS were included for the meta-analysis and 232 matched control subjects were enrolled and results were presented. The association of PDE4D gene polymorphism with IS in various populations was examined. The results suggested that single nucleotide polymorphism (SNP), SNP 83 in PDE4D gene was significantly related with susceptibility to IS. The meta-analysis also showed that PDE4D gene was associated with an enhanced risk of IS. The meta-analysis suggested that PDE4D SNP 87 constitutes an independent risk factor for IS development. To the best of our knowledge, the present meta-analysis reveals a number of possible associations between PDE4D gene polymorphism and IS.

Vascular Genetic Variants and Ischemic Stroke Susceptibility in Albanians from the Republic of Macedonia

BACKGROUND

Acute first-ever ischemic stroke (FIS) is a heterogeneous, polygenic disorder. The contribution of vascular genetic variants as inherited causes of ischemic stroke has remained controversial.

AIM

To examine the association of genetic variants in vascular factors with the occurrence of FIS.

MATERIAL AND METHODS

The current research was performed in a group of 39 patients with FIS (study group) and 102 healthy volunteers (control group). We analyzed the prevalence of vascular genetic variants in following genes: factor V, prothrombin, methylenetetrahydrofolate reductase (MTHFR), factor XIII, plasminogen activator 1, endothelial protein C receptor (EPCR), apolipoprotein B, apolipoprotein E, β-fibrinogen, human platelet antigen 1, angiotensin-converting enzyme (ACE), endothelial nitric oxide synthase (eNOS) and lymphotoxin alpha.

RESULTS

It was found that heterozygous LTA 804C>A and FXIII V34L Leu/Leu were significantly more frequent in patients with FIS than in control group (p = 0.036 and p = 0.017, respectively). The frequency of FXIII V34L Val/Val was significantly lower in patients with FIS than in control group (p = 0.020). Other frequencies of vascular gene variants in patients with FIS and in control group were not significantly different.

CONCLUSIONS

This is the first comprehensive study to present data indicating that polymorphism of vascular genes in the prevalence of acute FIS exists in the Albanian population from the Republic of Macedonia. Variations in these genes have been detected in patients with acute FIS, suggesting that their combination might act in a susceptible or protective manner in this Albanian population.

Ischemic Stroke and Six Genetic Variants in CRP, EPHX2, FGA, and NOTCH3 Genes: A Meta-Analysis

BACKGROUND

Ischemic stroke (IS) is a leading cause of death and disability worldwide. As genetic heritability for IS is estimated at about 35%-40%, the identification of genetic variants associated with IS risk is of great importance. The main objective of this study was to carry out a meta-analysis for polymorphisms in CRP, EPHX2, FGA, and NOTCH3 genes and the risk for IS.

METHODS

Literature search for 6 candidate polymorphisms and IS was conducted using HuGE Navigator, PubMed, and Google Scholar databases. Meta-Analyst program was used to calculate pooled odds ratios (ORs) with a random effects model.

RESULTS

Twenty-five published studies for 6 candidate polymorphisms were included: CRP-rs1800947 (5 studies), CRP-rs1205 (3 studies), EPHX2-rs751141 (5 studies), FGA-rs6050 (6 studies), NOTCH3-rs3815188 (3 studies), and NOTCH3-rs1043994 (3 studies), for a total number of 7,825 IS cases and 56,532 control subjects. We did not find significant pooled ORs (P values > .05) for any of the genetic variants evaluated in this work.

CONCLUSIONS

Our meta-analysis results did not show significant associations between these 6 polymorphisms in 4 candidate genes and IS, despite the functional role of some of these single nucleotide polymorphisms (e.g., rs6050 in FGA gene). Future studies are needed to identify additional main genetic risk factors for IS in different populations.

Association between lymphotoxin alpha (-252 A/G and -804 C/A) gene polymorphisms and risk of stroke in North Indian population: a hospital-based case-control study

PURPOSE

Lymphotoxin alpha (LTA), a proinflammatory cytokine, plays an important role in promoting atherosclerosis which is an independent risk factor for stroke. Recent genetic studies have suggested that polymorphisms in the LTA gene, which affect its expression and biological function, may contribute to the development of stroke. The aim of this case-control study was to determine the association between LTA (-252 A/G and -804 C/A) gene polymorphisms and risk of stroke.

METHODS

Genotyping was determined by using SNaPshot method for 250 ischemic stroke (IS) patients, 250 age and sex matched IS free controls, 100 intracerebral hemorrhage (ICH) patients and 100 age and sex matched ICH free controls. Conditional logistic regression analysis with adjusting multiple demographic and risk factor variables was used to calculate the strength of association between LTA (-252 A/G and -804 C/A) gene polymorphisms and risk of stroke. The linkage disequilibrium (LD) was analyzed by using HaploView 4.2 software.

RESULTS

The distribution of LTA (-252 A/G and -804 C/A) genotypes was consistent with Hardy-Weinberg equilibrium. Adjusted conditional logistic regression analysis showed no significant association between LTA (-252 A/G and -804 C/A) gene polymorphisms and risk of both IS and ICH. Based on Trial of Org 10172 in Acute Stroke Treatment (TOAST) classification, a significant association between LTA -252 A/G gene polymorphism and small vessel disease subtype of IS under dominant model (OR, 2.06; 95% CI, 1.03-4.12; p value 0.04) with the risk of IS was observed. No LD was observed for both single nucleotide polymorphisms (SNPs) in north Indian population.

CONCLUSION

Neither -252 G/A nor -804 C/A polymorphism of the LTA gene was found to be associated with overall stroke as well as any subtype of IS excluding SVD in North Indian population.

Vitamin D, vitamin D binding protein gene polymorphisms, race and risk of incident stroke: the Atherosclerosis Risk in Communities (ARIC) study

BACKGROUND AND PURPOSE

Low vitamin D levels, measured by serum 25-hydroxyvitamin D [25(OH)D], are associated with increased stroke risk. Less is known about whether this association differs by race or D binding protein (DBP) single nucleotide polymorphism (SNP) status. Our objective was to characterize the associations of and interactions between 25(OH)D levels and DBP SNPs with incident stroke. It was hypothesized that associations of low 25(OH)D with stroke risk would be stronger amongst persons with genotypes associated with higher DBP levels.

METHODS

25(OH)D was measured by mass spectroscopy in 12 158 participants in the Atherosclerosis Risk in Communities (ARIC) study (baseline 1990-1992, mean age 57 years, 57% female, 23% black) and they were followed through 2011 for adjudicated stroke events. Two DBP SNPs (rs7041, rs4588) were genotyped. Cox models were adjusted for demographic/behavioral/socioeconomic factors.

RESULTS

During a median of 20 years follow-up, 804 incident strokes occurred. The lowest quintile of 25(OH)D (<17.2 ng/ml) was associated with higher stroke risk [hazard ratio (HR) 1.34 (1.06-1.71) versus highest quintile]; this association was similar by race (P interaction 0.60). There was weak evidence of increased risk of stroke amongst those with 25(OH)D < 17.2 ng/ml and either rs7041 TG/GG [HR = 1.29 (1.00-1.67)] versus TT genotype [HR = 1.19 (0.94-1.52)] (P interaction 0.28) or rs4588 CA/AA [HR = 1.37 (1.07-1.74)] versus CC genotype [HR = 1.14 (0.91-1.41)] (P interaction 0.11).

CONCLUSIONS

Low 25(OH)D is a risk factor for stroke. Persons with low 25(OH)D who are genetically predisposed to high DBP (rs7041 G, rs4588 A alleles), who therefore have lower predicted bioavailable 25(OH)D, may be at greater risk for stroke, although our results were not conclusive and should be interpreted as hypothesis generating.

Race and Vitamin D Binding Protein Gene Polymorphisms Modify the Association of 25-Hydroxyvitamin D and Incident Heart Failure: The ARIC (Atherosclerosis Risk in Communities) Study

OBJECTIVES

This study sought to determine if low serum 25-hydroxyvitamin D (25[OH]D) is associated with incident heart failure (HF) and if the association is: 1) partly mediated by traditional cardiovascular risk factors; 2) stronger among whites than blacks; and 3) stronger among those genetically predisposed to having high levels of vitamin D binding protein (DBP).

BACKGROUND

Suboptimal 25(OH)D is a potential cardiovascular risk factor.

METHODS

A total of 12,215 ARIC (Atherosclerosis Risk in Communities) study participants free of HF at baseline (1990 to 1992; median age, 56; 24% black) were followed through 2010. Total serum 25(OH)D was measured at baseline using liquid chromatography-mass spectrometry. Incident HF events were identified by a hospital discharge code of ICD9-428 and parallel International Classification of Diseases codes for HF deaths.

RESULTS

During 21 years of follow-up, 1,799 incident HF events accrued. The association between 25(OH)D and HF varied by race (p-interaction = 0.02). Among whites, risk was 2-fold higher for those in the lowest (≤17 ng/ml) versus highest (≥31 ng/ml) quintile of 25(OH)D. The association was attenuated but remained significant with covariate adjustment. In blacks there was no overall association. In both races, those with low 25(OH)D and the rs7041 G allele, which predisposes to high DBP, were at greater risk (p-interaction = 0.01).

CONCLUSIONS

Low serum 25(OH)D was independently associated with incident HF among whites, but not among blacks. However, in both races, low 25(OH)D was associated with HF risk among those genetically predisposed to high DBP. These findings provide novel insight into metabolic differences that may underlie racial variation in the association between 25(OH)D and cardiovascular risk.

Association between PON1 L55M polymorphism and ischemic stroke: a systematic review and meta-analysis

OBJECTIVE

The present study aims to evaluate the relation between PON1 L55M polymorphism and ischemic stroke by a meta-analysis method.

METHODS

English and Chinese databases were retrieved to find qualified studies; a random or fixed effects model was used to merge the odds ratio (OR); Q test was used to assess the heterogeneity among studies, and Egger's test and funnel plot were used for the assessment of publication bias.

RESULTS

14 studies were included in the meta-analysis; in total populations, there was no association between PON1 gene L55M polymorphism and ischemic stroke in additive, dominant, and recessive model, respectively. Furthermore, we did not found associations between L55M and ischemic stroke in Asian or Caucasian population.

CONCLUSION

Available evidences suggested that L55M polymorphism had no effect on the risk of ischemic stroke. However, this conclusion needs further validation by larger sample and well-designed studies.

Tumor necrosis factor beta NcoI polymorphism (rs909253) is associated with inflammatory and metabolic markers in acute ischemic stroke

Polymorphisms in genes coding for pro-inflammatory molecules represent important factors for the pathogenesis and outcome of stroke. The aim of this study was to evaluate the relationship between the tumor necrosis factor beta (TNF-β) NcoI (rs909253) polymorphism with inflammatory and metabolic markers in acute ischemic stroke. Ninety-three patients and 134 controls were included. The TNF-β polymorphism was determined using PCR-RFLP with NcoI restriction enzyme. Stroke subtypes and neurological deficit score were evaluated. White blood cell counts, erythrocyte sedimentation rate (ESR), plasma levels of IL-6 and TNF-α, serum high sensitivity C-reactive Protein (hsCRP), serum lipid profile, plasma levels of glucose and insulin, and homeostatic model assessment of insulin resistance (HOMA-IR) were determined. Stroke patients presented higher white blood cell counts, hsCRP, ESR, glucose, insulin, and HOMA-IR, and lower HDL cholesterol than controls (p < 0.01). There was no difference in genotypic and allelic frequency of TNF-β NcoI polymorphism among patients and controls (p > 0.05). However, stroke patients carrying the TNFB2/B2 genotype presented higher levels of TNF-α, white blood cell counts, total cholesterol, LDL cholesterol, glucose, insulin, and HOMA-IR than those with other genotypes (p < 0.05). White blood cells, IL-6, hsCRP, and ESR were positively correlated with the neurological deficit of the patients (p < 0.05). Taken together, TNF-β NcoI polymorphism, by itself, was not associated with increased susceptibility for stroke development. However, the homozygous genotype for the allele TNFB2 was associated with higher expression of classical inflammatory and metabolic markers of development and outcome of stroke than other genotypes. The identification of variant alleles might allow both better prediction of susceptibility for stroke as well the identification of novel stroke mechanisms that could be target to new therapeutic approaches. Stroke patients carrying the TNFB2 variant allele could have a beneficial effect with the anti-inflammatory therapies in the early inflammatory phase of stroke.

Association of variants in KCNK17 gene with ischemic stroke and cerebral hemorrhage in a Chinese population

BACKGROUND

KCNK17 (potassium channel, subfamily K, member17) has a role in the pathogenesis of stroke. We reported previously that rs10947803 single-nucleotide polymorphism (SNP) in KCNK17 is associated with cerebral hemorrhage in a Chinese population. The aim of the present study was to examine other SNPs in the KCNK17 gene that are associated with cerebral hemorrhage and other subtypes of stroke in the Chinese population.

METHODS

A total of 1356 subjects with stroke and 1225 control patients were examined by a case-control methodology. The SNPs (rs12214600, rs12195376, rs2758912, and rs10807204) in KCNK17 gene were genotyped with the TaqMan real-time polymerase chain reaction assay.

RESULTS

rs12214600 SNP in KCNK17 was significantly associated with cerebral hemorrhage (unadjusted odds ratio = .55, 95% confidence interval = .35-.86, P = .008, q = .0328) under the allele model. After adjusting for age, sex, and hypertension, we found that the association remained significant (odds ratio = .56, 95% confidence interval = .35-.90, P = .0158). There was no association detected for other SNPs in KCNK17 with cerebral hemorrhage, and none of the SNPs in KCNK17 had an association with ischemic stroke.

CONCLUSIONS

The T carrier of an SNP (rs12214600) is associated with reduced risk of cerebral hemorrhage in the Chinese population, together with previous findings that SNPs rs10947803 and rs12214600 in the KCNK17 gene are associated with hemorrhagic stroke, but none of the SNPs tested had an association with ischemic stroke. KCNK17 may be important in the pathogenesis of cerebral hemorrhage.

Association of CVD candidate gene polymorphisms with ischemic stroke and cerebral hemorrhage in Chinese individuals

BACKGROUND

Contribution of cardiovascular disease related genetic risk factors for stroke are not clearly defined. We performed a genetic association study to assess the association of 56 previously characterized gene variants in 34 candidate genes from cardiovascular disease related biological pathways with ischemic stroke and cerebral hemorrhage in a Chinese population.

METHODS

There were 1280 stroke patients (1101 with ischemic stroke and 179 with cerebral hemorrhage) and 1380 controls in the study. The genotypes for 56 polymorphisms of 34 candidate genes were determined by the immobilized probe approach and the associations of gene polymorphisms with ischemic stroke and cerebral hemorrhage were performed by logistic regression under an allelic model.

RESULTS

After adjusting for age, sex, BMI and hypertension status by logistic regression analysis, we found that NPPA rs5063 was significantly associated with both ischemic stroke (odds ratio [OR] 0.69; 95% confidence interval [CI], 0.52 to 0.90; P = 0.006) and cerebral hemorrhage(OR = 0.39; 95%CI, 0.19 to 0.78; P = 0.007). In addition, MTHFR rs1801133 also was associated with cerebral hemorrhage (OR = 1.48; 95%CI, 1.16 to 1.89; P = 0.001) but not with ischemic stroke (OR = 1.08; 95%CI, 0.96 to 1.22; P = 0.210). After false discovery rate (FDR) correction, the association of NPPA rs5063 and MTHFR rs1801133 with cerebral hemorrhage remained significant.

CONCLUSIONS

The NPPA rs5063 is associated with reduced risk for cerebral hemorrhage and MTHFR rs1801133 is associated with increased risk of cerebral hemorrhage in a Chinese population.

Epigenetic patterns of two gene promoters (TNF-α and PON) in stroke considering obesity condition and dietary intake

Some causal bases of stroke remain unclear, but the nutritional effects on the epigenetic regulation of different genes may be involved. The aim was to assess the impact of epigenetic processes of human tumor necrosis factor (TNF-α) and paraoxonase (PON) promoters in the susceptibility to stroke when considering body composition and dietary intake. Twenty-four patients (12 non-stroke/12 stroke) were matched by sex (12 male/12 female), age (mean 70 ± 12 years old), and BMI (12 normal-weight/12 obese; mean 28.1 ± 6.7 kg/m(2)). Blood cell DNA was isolated and DNA methylation levels of TNF-α (-186 to +349 bp) and PON (-231 to +250 bp) promoters were analyzed by the Sequenom EpiTYPER approach. Histone modifications (H3K9ac and H3K4me3) were analyzed also by chromatin immunoprecipitation in a region of TNF-α (-297 to -185). Total TNF-α promoter methylation was lower in stroke patients (p < 0.001) and showed no interaction with body composition (p = 0.807). TNF-α and PON total methylation levels correlated each other (r = 0.44; p = 0.031), especially in stroke patients (r = 0.72; p = 0.008). The +309 CpG methylation site from TNF-α promoter was related to body weight (p = 0.027) and the region containing three CpGs (from -170 to -162 bp) to the percentage of lipid intake and dietary indexes (p < 0.05) in non-stroke patients. The methylation of PON +15 and +241 CpGs was related to body weight (p = 0.021), waist circumference (p = 0.020), and energy intake (p = 0.018), whereas +214 was associated to the quality of the diet (p < 0.05) in non-stroke patients. When comparing stroke vs non-stroke patients regarding the histone modifications analyzed at TNF-α promoter, no changes were found, although a significant association was identified between circulating TNF-α level and H3K9ac with H3K4me3. TNF-α and PON promoter methylation levels could be involved in the susceptibility to stroke and obesity outcome, respectively. The dietary intake and body composition may influence this epigenetic regulation in non-stroke patients.

The role of classic risk factors and prothrombotic factor gene mutations in ischemic stroke risk development in young and middle-aged individuals

BACKGROUND

In young individuals, a genetically predisposing hypercoagulability and classic modifying risk factors can act synergistically on the ischemic stroke risk development. The aim of the study was to compare the prevalence of classic vascular risk factors and polymorphisms of the G20210A coagulation factor II (prothrombin), Arg506Glu coagulation factor V Leiden, C677T methylenetetrahydrofolate reductase (MTHFR), and 4G/5G plasminogen activator inhibitor-1 (PAI-1) and the impact of these gene mutations and classic vascular risk factors on the overall stroke risk in individuals aged 55 years or younger.

METHODS

The study included 155 stroke patients aged 55 years or younger and 150 control subjects. Stroke prevalence and odds ratio (OR) were assessed for the following parameters: G20210A prothrombin, Arg506Glu factor V Leiden, C677T MTHFR, and 4G/5G PAI-1 polymorphisms; total number of study polymorphisms in a particular subject (genetic sum); and classic vascular risk factors of hypertension, obesity, diabetes mellitus, cigarette smoking, hypercholesterolemia, hypertriglyceridemia, and elevated levels of low-density lipoprotein (LDL) cholesterol and very low-density lipoprotein cholesterol.

RESULTS

The prevalence of hypertension (P < .001), smoking (P < .001), decreased HDL cholesterol levels (P < .001), obesity (P = .001), elevated LDL cholesterol (P = .036), C677T MTHFR polymorphism (P < .001), and genetic sum was significantly higher in the group of stroke patients. The following parameters were found to act as independent risk factors for ischemic stroke: decreased HDL cholesterol level (P < .001; OR 4.618; 95% confidence interval [CI] 2.381-8.957); hypertension (P = .001; OR 2.839; 95% CI 1.519-5.305); obesity (P = .040; OR 2.148; 95% CI 1.036-4.457); smoking (P = .001; OR 2.502; 95% CI 1.436-4.359); and genetic sum as a continuous variable (P < .01; OR 2.307; 95% CI 1.638-3.250).

CONCLUSIONS

Gene mutations of the procoagulable and proatherosclerotic factors investigated exerted a synergistic action in the development of overall risk of ischemic stroke in young and middle-aged individuals.

Validation and quantification of genetic determinants of lipoprotein-a levels and predictive value for angiographic coronary artery disease

Lipoprotein(a) (Lp[a]) has gained attention as a heritable coronary artery disease (CAD) risk factor and therapeutic target. Two genetic variants in the LPA gene have been reported to influence Lp(a) levels and increase CAD risk. The aim of this study was to prospectively test these variants for their associations with Lp(a) and CAD risk. Participants (n = 1,400) in the Intermountain Heart Collaborative Study Registry who had Lp(a) cholesterol levels determined at coronary angiography were genotyped for rs3798220 and rs1045587 in LPA. Variants were detected by Taqman polymerase chain reaction. Chi-square and linear and logistic regression tests were used as appropriate among genotypes for Lp(a) and angiographic CAD. Age averaged 63 years; 65% were men; and severe CAD was present in 57%, mild CAD in 12%, and no CAD in 31%. Minor allele frequencies were 0.023 for rs3798220 and 0.090 for rs10455872. In multivariate modeling, only rs10455872 (odds ratio [OR] 2.33, 95% confidence interval [CI] 1.67 to 3.33, p = 1.75 × 10⁻⁹) and rs3798220 (OR 1.99, 95% CI 0.99 to 4.00, p = 0.065) contributed to the prediction of elevated Lp(a) cholesterol. Lp(a) cholesterol was weakly associated with CAD (OR 1.17, 95% CI 1.00 to 1.37, p = 0.055). Rs10455872 strongly predicted prevalent CAD (per allele OR 1.43, 95% CI 1.07 to 1.91, p = 0.0172); the effect size for the rare rs3798220 variant was similar (dominant OR 1.47, 95% CI 0.81 to 2.67, p = 0.20), but power was limited to demonstrate significance. The combined genotype explained only a small percentage (≤4%) of variability in Lp(a) cholesterol and prevalence of angiographic CAD. In conclusion, heritable contributions of LPA rs10455872 and rs3798220 to Lp(a) cholesterol levels and to angiographic CAD were prospectively assessed in this study. The percentage of intersubject variability in Lp(a) cholesterol and the percentage of prevalent CAD explained were small.

Genetic variation of platelet function and pharmacology: an update of current knowledge

Platelets are critically involved in atherosclerosis and acute thrombosis. The platelet phenotype shows a wide variability documented by the inherited difference of platelet reactivity, platelet volume and count and function of platelet surface receptors. Several candidate genes have been put into focus and investigated for their functional and prognostic role in healthy individuals and patients with cardiovascular (CV) disease treated with antiplatelet agents. In addition to genetic variation, other clinical, disease-related and demographic factors are important so-called non-genetic factors. Due to the small effect sizes of single nucleotide polymorphisms (SNP) in candidate genes and due to the low allele frequencies of functional relevant candidate SNPs, the identification of genetic risk factors with high predictive values generally depends on the sample size of study cohorts. In the post-genome era new array and bioinformatic technologies facilitate high throughput genome-wide association studies (GWAS) for the identification of novel candidate genes in large cardiovascular cohorts. One of the crucial aspects of platelet genomic studies is the precise definition of a specific clinical phenotype (e.g. stent thrombosis) as this will impact importantly the findings of genomic studies like GWAS. Here, we provide an update on genetic variation of platelet receptors and drug metabolising enzymes under specific consideration of data derived by GWAS. The potential impact of this information and the role in personalised therapeutic concepts will be discussed.

The rs10947803 SNP of KCNK17 is associated with cerebral hemorrhage but not ischemic stroke in a Chinese population

KCNK17 (potassium channel, subfamily K, member17) was first discovered to associate with the pathogenesis of ischemic stroke in the first genome-wide association study. The rs10947803 SNP in KCNK17 is significantly associated with ischemic stroke in Caucasian populations. The aim of the present study was to investigate the association with strokes in the Chinese population. A total of 1364 stroke patients and 1293 controls were examined using a case-control methodology. The rs10947803 SNP in KCNK17 was genotyped by a TaqMan real-time PCR assay. The rs10947803 SNP (A allele) of KCNK17 was significantly associated with cerebral hemorrhage (for AA+AC versus CC, unadjusted odds ratio [OR]=1.70; 95% confidence interval [CI], 1.08-2.69; P=0.020). After adjustment for age and sex, the association remained significant for AA+AC versus CC, OR=1.65; 95% CI, 1.04-2.62; P=0.033. In addition, the rs10947803 SNP in KCNK17 was not associated with ischemic stroke (for AA+AC versus CC, unadjusted OR=0.92; 95% CI, 0.81-1.05; P=0.212, after age- and sex-adjustment, OR=0.87; 95% CI, 0.72-1.05; P=0.143). The rs10947803 SNP (A allele) in KCNK17 increases the risk of cerebral hemorrhage but not ischemic stroke in the Chinese population.

Protein therapeutics targeted at the TNF superfamily

Protein-based drugs with their unequivocal specificity achieved the long sought milestone of selectively disrupting cytokine pathways to alleviate ongoing inflammation. Tumor necrosis factor (TNF), a member of the superfamily of cytokines involved in regulating immune and inflammatory processes, provides an exemplary model of protein therapeutics. Antibody and receptor-based inhibitors of TNF modify inflammation leading to dramatic improvement in patients with certain autoimmune diseases. Collectively, the structure, specificity and valence of these protein-based drugs provide direct evidence that the essential mechanism of action is antagonism of the ligand-receptor interaction. Accumulating clinical knowledge regarding TNF inhibitors also provide insights into the mechanisms involved in different autoimmune diseases. Experience in the development of an arsenal of biologics directed at TNF has additionally contributed to knowledge toward overcoming the challenges of protein drugs, which include production, delivery, antigenicity and pharmacodynamics. Dramatic clinical outcomes with TNF inhibitors are driving investigation and development of biologics toward other members of the TNF superfamily to selectively alter functional properties of the immune system.

Common variants of the vitamin D binding protein gene and adverse health outcomes

The vitamin D binding protein (DBP) is the major plasma carrier for vitamin D and its metabolites, but it is also an actin scavenger, and is the precursor to the immunomodulatory protein, Gc-MAF. Two missense variants of the DBP gene - rs7041 encoding Asp432Glu and rs4588 encoding Thr436Lys - change the amino acid sequence and alter the protein function. They are common enough to generate population-wide constitutive differences in vitamin D status, based on assay of the serum metabolite, 25-hydroxyvitamin D (25OHD). Whether these variants also influence the role of vitamin D in an immunologic milieu is not known. However, the issue is relevant, given the immunomodulatory effects of DBP and the role of protracted innate immune-related inflammation in response to tissue injury or repeated infection. Indeed, DBP and vitamin D may jointly or independently contribute to a variety of adverse health outcomes unrelated to classical notions of their function in bone and mineral metabolism. This review summarizes the reports to date of associations between DBP variants, and various chronic and infectious diseases. The available information leads us to conclude that DBP variants are a significant and common genetic factor in some common disorders, and therefore, are worthy of closer attention. In view of the heightened interest in vitamin D as a public health target, well-designed studies that look simultaneously at vitamin D and its carrier in relation to genotypes and adverse health outcome should be encouraged.

Association between Glu298Asp/677C-T single nucleotide polymorphism in the eNOS/MTHRF gene and blood stasis syndrome of ischemic stroke

Blood stasis syndrome of ischemic stroke (BSS-IS) is a common clinical phenotype that may be affected by certain mutagenic environmental factors or chemotherapeutic drugs; however, the role of susceptibility genes remains unclear. Previous studies have shown that ischemic stroke (IS) was closely associated with the Glu298Asp polymorphism in the eNOS gene and the 677C-T (Ala→Val) polymorphism in methylenetetrahydrofolate reductase (MTHRF) gene. Therefore, these two single nucleotide polymorphisms (SNPs) were selected to detect their associations with BSS-IS in this study. A SNP chip was employed to screen the SNP variation between both groups, and the results were verified using denaturing high-performance liquid chromatography (DHPLC) and restriction fragment length polymorphism (RFLP). The results confirmed that the TT genotype of Glu298Asp in the eNOS gene may be one of the risk factors associated with BSS-IS, while the genotype of 677C-T (Ala→Val) in the MTHRF gene may not be relevant to BSS-IS.

Association of inflammatory gene polymorphisms with ischemic stroke in a Chinese Han population

BACKGROUND

Inflammatory mechanisms are important in stroke risk, and genetic variations in components of the inflammatory response have been implicated as risk factors for stroke. We tested the inflammatory gene polymorphisms and their association with ischemic stroke in a Chinese Han population.

METHODS

A total of 1,124 ischemic stroke cases and 1,163 controls were genotyped with inflammatory panel strips containing 51 selected inflammatory gene polymorphisms from 35 candidate genes. We tested the genotype-stroke association with logistic regression model.

RESULTS

We found two single nucleotide polymorphisms (SNPs) in CCL11 were associated with ischemic stroke. After adjusting for multiple testing using false discovery rate (FDR) with a 0.20 cut-off point, CCL11 rs4795895 remained statistically significant. We further stratified the study population by their hypertension status. In the hypertensive group, CCR2 rs1799864, CCR5 rs1799987 and CCL11 rs4795895 were nominally associated with increased risk of stroke. In the non-hypertensive group, CCL11 rs3744508, LTC4S rs730012, FCER1B rs569108, TGFB1 rs1800469, LTA rs909253 and CCL11 rs4795895 were associated with ischemic stroke. After correction for multiple testing, CCR2 rs1799864 and CCR5 rs1799987 remained significant in the hypertensive group, and CCL11 rs3744508, LTC4S rs730012, FCER1B rs569108, TGFB1 rs1800469, LTA rs909253 remained significant in the non-hypertensive group.

CONCLUSIONS

Our results indicate that inflammatory genetic variants are associated with increased risk of ischemic stroke in a Chinese Han population, particularly in non-hypertensive individuals.

PON gene polymorphisms and ischaemic stroke: a systematic review and meta analysis

BACKGROUND

Paraoxonase is known to play an important role in the pathophysiology of atherosclerosis. Genetic variants of the paraoxonase gene have been implicated as risk factors for atherosclerotic diseases such as coronary artery disease, but individual genetic association studies examining the relationship between the paraoxonase gene polymorphisms and ischaemic stroke have yielded inconsistent results.

AIM

This study aimed to evaluate the association between the paraoxonase gene variants and ischaemic stroke using systematic review with meta-analysis.

METHODS

Relevant studies were identified by searching English and Chinese databases extensively. Allele and genotype frequencies for each included study were extracted. The odds ratio was calculated using a random-effects or fixed-effects model. A Q statistic was used to evaluate homogeneity, and Egger's test and funnel plot were used to assess publication bias.

RESULTS

A total of 28 studies were included and identified for the current meta-analysis. It was found that the R allele or RR genotype of paraoxonase 1 Q192R polymorphism had an increased risk for ischaemic stroke in the general population (192R allele: odds ratio: 1·21, 95% confidence interval: 1·08-1·35, P = 0·0009 and 192RR genotype: odds ratio: 1·25, 95% confidence interval: 1·06-1·49, P = 0·009 in general population, respectively), but there was no significant association between other genetic variants of paraoxonase gene and ischaemic stroke.

CONCLUSIONS

Existing evidence indicates that the Q192R polymorphism (the R allele and RR genotype) is associated with an increased risk of ischaemic stroke in the general population. Future studies with larger sample sizes will be necessary to confirm the present results.

Potential association between frequent nonsynonymous variant of NPPA and cardioembolic stroke

Atrial natriuretic peptide (ANP, also known as NPPA) and brain natriuretic peptide (BNP, also known as NPPB) have been determined as genetic factors for several diseases, including stroke and myocardial infarction, in human and rat models. To investigate the potential association between polymorphisms of the NPPA gene and stroke in a Korean population, nine single-nucleotide polymorphisms (SNPs) of NPPA and NPPB genes were genotyped in a total of 941 Korean subjects, including 674 stroke patients (109 hemorrhagic and 565 ischemic) and 267 unaffected controls. Genotype comparisons of the targeted alleles revealed that there were no significant associations between stroke patients and control subjects, or among hemorrhagic, ischemic, and control groups. However, in logistic analysis for Trial of Org 10172 in Acute Stroke Treatment (TOAST) classification of ischemic stroke, nonsynonymous rs5065 (STOP152Arg) and rs5067 in 3'UTR of NPPA, which were in complete linkage disequilibrium, showed significant associations with cardioembolic stroke. These two SNPs showed higher frequencies in cardioembolic stroke patients than those in controls and ischemic patients with small-vessel occlusion (p=0.002, adjusted p=0.02). It was also found that NPPA rs5065C allele in all of the Korean subjects existed as heterozygous compared with Caucasian and African populations. Although further replications in larger cardioembolic stroke subjects are required, our preliminary findings suggest that the nonsynonymous rs5065C of the NPPA gene, which could produce a new or dysfunctional transcript, is possibly associated with cardioembolism.

The influence of genetics on response to treatment with ranibizumab (Lucentis) for age-related macular degeneration: the Lucentis Genotype Study (an American Ophthalmological Society thesis)

PURPOSE

Age-related macular degeneration (AMD) has a complex etiology arising from genetic and environmental influences. This past decade have seen several genes associated with the disease. Variants in five genes have been confirmed to play a major role. The objective of this study was to evaluate whether genes influence treatment response to ranibizumab for neovascular AMD. The hypothesis was that an individual's genetic variation will determine treatment response.

METHODS

The study was a two-site prospective open-label observational study of patients newly diagnosed with exudative (neovascular) AMD receiving intravitreal ranibizumab therapy. Treatment-naïve patients were enrolled at presentation and received monthly "as needed" therapy. Clinical data was collected monthly and DNA extracted. Genotyping was performed using the Illumina (San Diego, California) 660-Quad single-nucleotide polymorphism (SNP) chip. Regression analyses were performed to identify SNPs associated with treatment-response end points.

RESULTS

Sixty-five patients were enrolled. No serious adverse events were recorded. The primary outcome measure was change in ETDRS visual acuity at 12 months. A SNP in the CFH gene was found to be associated with less improvement in visual acuity while receiving ranibizumab therapy. The C3 gene, among others, was associated with reduced thickening and improved retinal architecture. VEGFA, FLT1, and CFH were associated with requiring fewer ranibizumab injections over the 12-month study.

CONCLUSIONS

This study is one of the first prospective pharmacogenetic study of intravitreal ranibizumab. Although preliminary, the results identify a number of putative genetic variants, which will be further examined by replication and functional studies to elucidate the complete pharmacogenetic architecture of therapy for AMD.

Siblings with ischemic stroke study: results of a genome-wide scan for stroke loci

BACKGROUND AND PURPOSE

Ischemic stroke has a strong familial component to risk. The Siblings With Ischemic Stroke Study (SWISS) is a genome-wide, family-based analysis that included use of imputed genotypes. The Siblings With Ischemic Stroke Study was conducted to examine the associations between single-nucleotide polymorphisms (SNPs) and risk of stroke and stroke subtypes within pairs.

METHODS

The Siblings With Ischemic Stroke Study enrolled 312 probands with ischemic stroke from 70 US and Canadian centers. Affected siblings were ascertained by centers and confirmed by central record review; unaffected siblings were ascertained by telephone contact. Ischemic stroke was subtyped according to Trial of Org 10172 in Acute Stroke Treatment criteria. Genotyping was performed with an Illumina 610 quad array (probands) and an Illumina linkage V array (affected siblings). SNPs were imputed by using 1000 Genomes Project data and MACH software. Family-based association analyses were conducted by using the sibling transmission-disequilibrium test.

RESULTS

For all pairs, the correlation of age at stroke within pairs of affected siblings was r=0.83 (95% CI, 0.78-0.86; P<2.2×10(-16)). The correlation did not differ substantially by subtype. The concordance of stroke subtypes among affected pairs was 33.8% (kappa=0.13; P=5.06×10(-4)) and did not differ by age at stroke in the proband. Although no SNP achieved genome-wide significance for risk of ischemic stroke, there was clustering of the most associated SNPs on chromosomes 3p (neuronal nitric oxide synthase) and 6p.

CONCLUSIONS

Stroke subtype and age at stroke in affected sibling pairs exhibit significant clustering. No individual SNP reached genome-wide significance. However, 2 promising candidate loci were identified, including 1 that contains neuronal nitric oxide synthase, although these risk loci warrant further examination in larger sample collections.