Polymorphisms in the genes for coagulation factors II, V, and VII in patients with ischemic heart disease

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Association Between R353Q (rs6046) Polymorphism in Factor VII with Coronary Heart Disease

A number of studies have showed the relationship between R353Q (rs6046) polymorphism in factor VII gene and coronary heart disease (CHD). However, the results remain controversial due to the limitations of the research objects and small sample size of individual study. We conducted this meta-analysis to validate the association between R353Q (rs6046) polymorphism and the risk of CHD.The relevant data was collected up to March 25, 2019 from PubMed, Web of Science, CNKI, and Wanfang databases. We examined all eligible studies using the Newcastle-Ottawa Quality Assessment Scale (NOS). The odds ratio (OR) and its corresponding 95% confidence interval (CI) were adopted to evaluate the relationship between the R353Q (rs6046) polymorphism and CHD. Stata version 14.0 (Stata Corporation, USA) was used in all statistical tests.There were at least 28 eligible studies, including 14626 cases and 17994 controls, included in our meta-analysis. R353Q (rs6046) polymorphism was associated with the reduced risk of CHD in four genetic models: allele model (Q versus R: OR = 0.79, 95% CI: 0.69 to 0.90, P < 0.001, I² = 56.4%), homozygote (co-dominant) model (QQ versus RR: OR = 0.72, 95% CI = 0.58 to 0.92, P = 0.004, I² = 5.8%), heterozygote (co-dominant) model (RQ versus RR: OR = 0.71, 95% CI = 0.58 to 0.86, P = 0.001, I² = 75.4%), and dominant model (RQ+QQ versus RR: OR = 0.74, 95% CI = 0.63 to 0.865, P < 0.001, I² = 64.1%) excluding recessive model (QQ versus RR+RQ: OR = 0.86, 95% CI = 0.57 to 1.28, P = 0.447, I² = 51.6%).The results of the current meta-analysis suggested that R353Q (rs6046) polymorphism was associated with the reduced risk of CHD, especially in Asians.

The Association of Hereditary Prothrombotic Risk Factors with ST-Elevation Myocardial Infarction

Objective

The ST- elevation myocardial infarction (STEMI), a serious health care problem, is commonly a thrombotic complication of coronary artery disease. We compare the STEMI patients and control group in terms of the possible causes of inherited thrombophilia including FactorV Cambridge G1091C, FactorV Leiden G1691A, MTHFRC677T, MTHFR A1298C, FactorII G20210A, Factor XIII (V34L), PAI-1, FGB, ITGB3, APOB, FVHR2, ACE gene variants.

Methods

Fifty-three patients with STEMI and 47 individuals without diagnosis of acute coronary syndrome were included in the study. Percutaneous coronary intervention was performed for patients with STEMI. Echocardiography was performed and inherited thrombophilia genes were evaluated in all subjects.

Results

The MTHFR A1298C, Factor XIII (V34L), ITGB, ACE and homozygous or compound heterozygous gene varations of inherited thrombophilia are significantly related with STEMI (p<0.05). Also significantly higher MTHFR A1298C, FactorV Leiden G1691A, PAI and ACE gene variations in MI patients who were smokers; Factor XIII (V34L), PAI and ACE gene variations in MI patients with HT; PAI and ACE gene variation in MI patients with FH and PAI gene variations in MI patients with HL were detected when compared with the control groups with all of the same risk factors (p<0.05).

Conclusion

Hereditary thrombophilia factors may show promise in the prevention and management of STEMI when supported studies with larger case series.

Polymorphism of R353Q (rs6046) in factor VII and the risk of myocardial infarction: A systematic review and meta-analysis

OBJECTIVE

Genetic components substantially contribute to the development of myocardial infarction (MI), and R353Q polymorphism (rs6046) in FVII gene has been suspected to be associated with the risk of MI.

METHODS

A meta-analysis was conducted on the links between R353Q polymorphism and the susceptibility of MI. A comprehensive literature search was performed on 8 electronic databases. The main effects of the genotypes were estimated using a logistic regression approach. The odds ratios with 95% confidence intervals were calculated using the conventional summary method meta-analysis. The possible sources of heterogeneity among the included studies were explored using meta-regression analysis and subgroup analysis.

RESULTS

A total of 18 eligible case-control studies, comprising of 4701 cases and 5329 controls, were included. No overall statistical relationship was identified between R353Q and MI by any of the genetic models. The meta-regression demonstrated that the Asian population, body mass index (BMI) category, and diabetes affected the heterogeneity. In addition, subgroup analyses showed that heterogeneities were identified in Asian population and BMI category, which highly agree with the results of meta-regression.

CONCLUSIONS

The current meta-analysis suggested that R353Q polymorphism was not associated with the MI risk. Asian population, BMI category, and diabetes might be related to the incidence of MI. However, large-scale, case-control studies with rigorous designs are essential to provide accurate evidence.

Diabetic macular oedema: under-represented in the genetic analysis of diabetic retinopathy

Diabetic retinopathy, a complication of both type 1 and type 2 diabetes, is a complex disease and is one of the leading causes of blindness in adults worldwide. It can be divided into distinct subclasses, one of which is diabetic macular oedema. Diabetic macular oedema can occur at any time in diabetic retinopathy and is the most common cause of vision loss in patients with type 2 diabetes. The purpose of this review is to summarize the large number of genetic association studies that have been performed in cohorts of patients with type 2 diabetes and published in English-language journals up to February 2017. Many of these studies have produced positive associations with gene polymorphisms and diabetic retinopathy. However, this review highlights that within this large body of work, studies specifically addressing a genetic association with diabetic macular oedema, although present, are vastly under-represented. We also highlight that many of the studies have small patient numbers and that meta-analyses often inappropriately combine patient data sets. We conclude that there will continue to be conflicting results and no meaningful findings will be achieved if the historical approach of combining all diabetic retinopathy disease states within patient cohorts continues in future studies. This review also identifies several genes that would be interesting to analyse in large, well-defined cohorts of patients with diabetic macular oedema in future candidate gene association studies.

Prothrombin G20210A (rs1799963) polymorphism increases myocardial infarction risk in an age-related manner: A systematic review and meta-analysis

G20210A polymorphism (rs1799963) within the prothrombin gene is associated with a higher circulation level of prothrombin, thus increasing the likelihood of developing myocardial infarction (MI). Opinions differ regarding the correlation between prothrombin G20210A genotype and MI risk, which prompted us to conduct a meta-analysis to determine this association. PubMed, EMBASE, Web of Science and CNKI were searched for pertinent reports. A total of 34 studies involving 14 611 MI cases and 84 358 controls were analyzed in this quantitative analysis. We found a statistically significant association between prothrombin G20210A polymorphism and MI in the allele model (A vs. G, OR = 1.43, 95%CI: 1.18–1.72), heterozygote model (GA vs. GG, OR = 1.41, 95%CI: 1.16–1.72) and dominant model (GA + AA vs. GG, OR = 1.41, 95%CI: 1.15–1.72). The association remains significant in Caucasians but not in non-Caucasians. Moreover, prothrombin G20210A polymorphism increases MI risk in an age-related manner. A further significant association was found in a subpopulation younger than 55 years (allele model, OR = 1.76, 95%CI: 1.32–2.35; heterozygote model, OR = 1.70, 95%CI: 1.24–2.33; dominant model, OR = 1.70, 95%CI: 1.24–2.34). Sensitivity analysis and publication bias analysis revealed stable and statistically robust results. Our meta-analysis demonstrated that prothrombin G20210A polymorphism may represent a risk factor for MI.

Genetic polymorphisms, Biochemical Factors, and Conventional Risk Factors in Young and Elderly North Indian Patients With Acute Myocardial Infarction

This study compared genetic polymorphisms (factor V Leiden [FVL] 1691G/A, factor VII [FVII] 10976G/A, FVII HVR4, platelet membrane glycoproteins GP1BA 1018C/T, GP1BA VNTR, integrin ITGB3 1565T/C, ITGA2 807C/T and methylenetetrahydrofolate reductase [MTHFR] 677C/T), biochemical (fibrinogen and homocysteine), and conventional risk factors in 184 young and 166 elderly north Indian patients with acute myocardial infarction (AMI). Univariate analysis revealed higher prevalence of hypertension and obesity in elderly patients while smoking, alcohol intake, and low socioeconomic status in young patients (P < .001). Although mean fibrinogen predominated (P = .01) in elderly patients, mean homocysteine was higher (P < .001) among young patients. Prevalence of hyperhomocysteinemia was greater in young than in elderly patients (odds ratio: 2.8, 95% confidence interval: 1.8-4.4, P < .001); however, genetic polymorphisms were equally prevalent in young and elderly patients. Multiple logistic regression analysis showed smoking (P < .001), alcohol intake (P = .046), and hyperhomocysteinemia (P = .001) to be associated with AMI in the young patients while hypertension (P = .006) in elderly patients. To conclude, smoking, alcohol intake, and elevated homocysteine are the risk factors for AMI among young while hypertension among elderly patients.

Integrative computational and experimental approaches to establish a post-myocardial infarction knowledge map

Vast research efforts have been devoted to providing clinical diagnostic markers of myocardial infarction (MI), leading to over one million abstracts associated with “MI” and “Cardiovascular Diseases” in PubMed. Accumulation of the research results imposed a challenge to integrate and interpret these results. To address this problem and better understand how the left ventricle (LV) remodels post-MI at both the molecular and cellular levels, we propose here an integrative framework that couples computational methods and experimental data. We selected an initial set of MI-related proteins from published human studies and constructed an MI-specific protein-protein-interaction network (MIPIN). Structural and functional analysis of the MIPIN showed that the post-MI LV exhibited increased representation of proteins involved in transcriptional activity, inflammatory response, and extracellular matrix (ECM) remodeling. Known plasma or serum expression changes of the MIPIN proteins in patients with MI were acquired by data mining of the PubMed and UniProt knowledgebase, and served as a training set to predict unlabeled MIPIN protein changes post-MI. The predictions were validated with published results in PubMed, suggesting prognosticative capability of the MIPIN. Further, we established the first knowledge map related to the post-MI response, providing a major step towards enhancing our understanding of molecular interactions specific to MI and linking the molecular interaction, cellular responses, and biological processes to quantify LV remodeling.

Heart attack, known medically as myocardial infarction, often occurs as a result of partial shortage of blood supply to a portion of the heart, leading to the death of heart muscle cells. Following myocardial infarction, complications might arise, including arrhythmia, myocardial rupture, left ventricular dysfunction, and heart failure. Although myocardial infarction can be quickly diagnosed using a various number of tests, including blood tests and electrocardiography, there have been no available prognostic tests to predict the long-term outcome in response to myocardial infarction. Here, we present a framework to analyze how the left ventricle responds to myocardial infarction by combining protein interactome and experimental results retrieved from published human studies. The framework organized current understanding of molecular interactions specific to myocardial infarction, cellular responses, and biological processes to quantify left ventricular remodeling process. Specifically, our knowledge map showed that transcriptional activity, inflammatory response, and extracellular matrix remodeling are the main functional themes post myocardial infarction. In addition, text analytics of relevant abstracts revealed differentiated protein expressions in plasma or serum expressions from patients with myocardial infarction. Using this data, we predicted expression levels of other proteins following myocardial infarction.

Combination of factor V Leiden and MTHFR mutations in myocardial infarction

Identifying patients who are at high risk of suffering myocardial infarction can be done by determining risk factors or by the adoption of molecular genetic testing for inherited thrombophilia. We report a case of myocardial infarction at a young age. The patient complained of dyspnea (stage III) and a burning pain of severe intensity that radiated to the left retrosternal side, but was not associated with palpitations or diaphoresis. A number of biochemical parameters were normal except for an elevated creatinine phosphokinase (CPK) level. Genetic testing revealed the subject to be heterozygous for both the factor V leiden and MTHFR C677T polymorphisms. The combination of these two mutations may be a high risk factor for myocardial infarction. Genetic screening for inherited thrombophilia in young patients, especially in the presence of a common risk factor, may be useful for primary thrombopro.phylaxis and in asymptomatic relatives of patients.

Prothrombotic gene polymorphisms and plasma factors in young North Indian survivors of acute myocardial infarction

The aim of this study was to evaluate the association of prothrombotic gene polymorphisms [factor V Leiden (FVL) 1691GA, factor VII (FVII) 10976GA, FVII HVR4, platelet membrane glycoproteins GP1BA 1018CT, GP1BA VNTR, integrin ITGB3 1565TC, integrin ITGA2 807CT and methylenetetrahydrofolate reductase (MTHFR) 677C/T], plasma factors (fibrinogen and homocysteine) and traditional risk factors with acute myocardial infarction (AMI) in 184 patients ≤ 40 years of age and 350 controls (≤ 40 years) from north India. Multiple logistic-regression analysis showed that hypertension (OR 1.9, 95 % CI 1.1-3.8, p = 0.042), diabetes mellitus (OR 10.5, 95 % CI 2.0-56.7, p = 0.006), smoking (OR 7.1, 95 % CI 3.7-13.6, p < 0.001), low socio-economic status (OR 13.5, 95 % CI 2.3-78.4, p = 0.004), high waist-hip ratio (OR 35.6, 95 % CI 11.1-53.7, p < 0.001) and FVL 1691GA (OR 6.0, 95 % CI 1.2-13.4, p = 0.03) were independent risk predictors of AMI in young. Elevated plasma fibrinogen also showed association with increased AMI risk. ITGA2 807C/T polymorphism showed protection against AMI in univariate analysis only, while GP1BA VNTR-ac (OR 0.4, 95 % CI 0.2-0.9, p = 0.033) showed significant protection even after adjusting for age and sex. Multinominal logistic-regression analysis showed gene-gene (GP1BA 1018C/T with GP1BA VNTR and ITGA2 807C/T with ITGB3 1565T/C polymorphisms) and gene-environment interactions (gene polymorphisms with smoking) operating in the occurrence of AMI in young. In conclusion, the role of inherited predisposition to thrombosis in complex, polygenic and multifactorial disease like AMI is limited to certain genetic factors, in combination with environmental factor like smoking.

Varied association of prothrombin G20210A polymorphism with coronary artery disease susceptibility in different ethnic groups: evidence from 15,041 cases and 21,507 controls

Published data on the association between prothrombin G20210A polymorphism and coronary artery disease (CAD) risk are inconclusive. To derive a more precise estimation of the relationship, a meta-analysis was performed. A total of 42 case-control studies including 15,041 cases and 21,507 controls were included in this meta-analysis. Overall, significantly elevated CAD risk was associated with prothrombin G20210A polymorphism (OR, 1.22; 95% CI 1.07-1.40; P=0.003) when 39 eligible studies were pooled into the meta-analysis. In the subgroup analysis, borderline statistically increased risk was found for myocardial infarction in 22 case-control studies (OR, 1.27; 95% CI 1.00-1.61; P=0.05). When stratified by ethnicity, significantly elevated risk was found in Europeans (OR, 1.19; 95% CI, 1.02-1.38; P=0.02). However, no statistical differences were found among Americans and Asians. In summary, this meta-analysis indicated that prothrombin G20210A allele is a low-penetrant risk factor for developing CAD in Europeans.

G20210A prothrombin gene polymorphism and coronary ischaemic syndromes: a phenotype-specific meta-analysis of 12 034 subjects

OBJECTIVE

To investigate the possible link between the G20210A prothrombin gene variant and different forms of ischaemic heart disease.

DESIGN

Phenotype-specific meta-analysis of 19 studies published within March 2002, globally including 4944 patients and 7090 controls. Sample size, inclusion criteria, geographical location, clinical presentation, age, cardiovascular risk factors, and angiographic extent of disease were extracted from each study. Analyses were done according to Mantel-Haenszel.

RESULTS

Overall, the odds ratio (OR) for unspecified ischaemic heart disease associated with the 20210A allele was 1.21 (95% confidence interval (CI) 0.99 to 1.59, n = 12 034). Similar findings were seen for acute coronary syndromes (unstable angina and myocardial infarction) and for myocardial infarction without age limits (OR 1.24, 95% CI 0.98 to 1.63, n = 10 240; and OR 1.19, 95% CI 0.93 to 1.58, n = 9765). The effects were similar in male and female subjects. In the 1931 subjects < 55 years of age, the OR for myocardial infarction increased to 1.77 (95% CI 1.16 to 3.42) and in the 1359 subjects < 45 years to 2.30 (95% CI 1.27 to 4.59). No significant association was found between the 20210A allele and the presence of angiographically documented coronary disease (OR 1.08, 95% CI 0.70 to 1.64, n = 3444). However, patients with 0/1 vessel disease at angiography showed a greater prevalence of the A allele than those with multivessel disease (relative risk 2.0, 95% CI 1.2 to 3.1, n = 2376).

CONCLUSIONS

G20210A prothrombin gene polymorphism may represent a modest but significant risk factor for myocardial infarction at young ages and favour the expression of ischaemic heart disease among individuals who have a limited extent of coronary atherosclerosis at angiography.

Association between factor V Leiden, prothrombin G20210A, and methylenetetrahydrofolate reductase C677T mutations and events of the arterial circulatory system: a meta-analysis of published studies

BACKGROUND

The association between the inherited gene mutations of factor V, prothrombin, and homocysteine metabolism and venous thromboembolic events is accepted widely; however, their influence on the arterial circulatory system remains controversial.

METHODS

We performed a MEDLINE search to identify published case-control and cohort studies correlating the factor V Leiden, prothrombin (PT) G20210A, and methylenetetrahydrofolate reductase (MTHFR) C677T (TT genotype) mutations with myocardial infarction, ischemic stroke, or peripheral vascular disease. Studies were included only when they adhered to specific diagnostic criteria for ischemic events and met the published methodological criteria. Odds ratios (ORs) with accompanying 95% CIs were calculated for each mutation and clinical end points with a random-effects model (DerSimonian and Laird method).

RESULTS

The association between inherited gene mutations and arterial ischemic events was modest: factor V Leiden mutation (OR, 1.21; 95% CI, 0.99-1.49), PT G20210A mutation (OR, 1.32; 95% CI, 1.03-1.69), and MTHFR TT mutation (OR, 1.20; 95% CI, 1.02-1.41). Subgroup analyses of younger patients (<55 years old) and of women revealed slightly stronger associations overall.

CONCLUSIONS

Genetic abnormalities specific to factor V, prothrombin,and homocysteine metabolism increase the risk for myocardial infarction and ischemic stroke, particularly among younger patients and women. Because the overall association is only modest, screening studies should be limited to carefully selected patient populations. The individual propensity for arterial and venous thrombosis is likely influenced by differing local mechanisms, systemic mechanisms, or both.

[Factor V Leiden and myocardial infarction: a case, review of the literature with a meta-analysis]

Mutation in blood coagulation factor V Leiden is the most frequently genetic polymorphism implied in venous thrombosis. A 57 year old man was hospitalised for acute myocardial infarction (MI). An emergency coronary angiography was performed, and no significant stenosis was observed. The haematologic check-up showed an heterozygous Leiden mutation of factor V. We report all publications about the relation between factor V Leiden and coronary thrombosis, and we performed a meta-analysis. We analysed the relation in general population and in subgroups, such as, younger and older, and patient with or without coronary stenosis. In global population, the meta-analysis did not found significant association between Factor V Leiden and myocardial infarction (OR = 1.25; IC = 0.97-1.58). In contrast, in patients less than < 55 years old after MI, Factor V Leiden prevalence was significantly higher than in control group (OR = 1.48; IC = 1.05-2.08). In addition, after MI without significant coronary stenosis Factor V Leiden prevalence was significantly higher than in normal patients (OR = 2.84; IC = 1.46-5.51). After MI, in patients without significant coronary stenosis, Factor V Leiden prevalence was significantly higher than in patients with significant coronary stenosis (OR = 3.26; IC = 1.67-6.36). Our study suggests that Factor V Leiden could be search after MI in young subjects and/or without significant stenosis.

Factor V Leiden: The Copenhagen City Heart Study and 2 meta-analyses

Factor V Leiden (FVL) is associated with venous thrombosis; however, an association between FVL and arterial thrombosis remains controversial. We investigated FVL as a risk factor for myocardial infarction (MI), ischemic stroke (IS), or non-MI ischemic heart disease (non-MI-IHD). The design was 3 case-control studies and 3 prospective studies with 21 years' follow-up. The setting was the general population in Copenhagen, Denmark. The participants for The Copenhagen City Heart Study were 20- to 95-year-old participants without cardiovascular disease (control population, n = 7907) or participants diagnosed with MI (n = 469), IS (n = 231), or non-MI-IHD (n = 365). In addition, 3 independent patient populations from Copenhagen University Hospital with MI (n = 493), IS (n = 231), or non-MI-IHD (n = 448) were included. We measured FVL genotype; major cardiovascular risk factors; and MI, IS, and non-MI-IHD incidence and prevalence. Prevalences of FVL heterozygotes and homozygotes in control subjects from the general population were 7.7% and 0.2%. Odds ratios and relative risks of MI in FVL carriers (heterozygotes + homozygotes) versus noncarriers were 1.24 (95% confidence interval [CI], 0.91-1.69) and 0.83 (0.58-1.20) in case-control and prospective studies, respectively. Corresponding risks for IS were 0.92 (95% CI, 0.56-1.53) and 0.68 (0.45-1.04), and for non-MI-IHD 1.01 (95% CI, 0.71-1.44) and 0.97 (0.66-1.42). Findings from The Copenhagen City Heart Study suggest that FVL is not associated with MI, IS, or non-MI-IHD.

Genetic variation in coagulation and fibrinolytic proteins and their relation with acute myocardial infarction: a systematic review

BACKGROUND

It is pathophysiologically conceivable that genetic variations in coagulation and fibrinolytic proteins are associated with the risk of myocardial infarction. Methods and Results- We performed a literature search to identify published case-control studies correlating the factor V Leiden or prothrombin G20210A mutations or fibrinogen G-455A or plasminogen activator inhibitor-1 (PAI-1) 4G/5G polymorphisms with the risk of myocardial infarction. Studies were included only if they used solid diagnostic criteria and complied with published methodological criteria. A common OR with corresponding 95% CI was calculated for the risk of myocardial infarction in a fixed-effect model according to Mantel-Haenszel. The factor V Leiden and prothrombin G20201A mutations did not significantly correlate with myocardial infarction (OR 1.26, 95% CI 0.94 to 1.67, P=0.12 and OR 0.89, 95% CI 0.59 to 1.35, P=0.6, respectively). Inclusion of the studies that investigated young patients (<55 years) made the association significant for factor V Leiden (OR 1.29, 95% CI 1.03 to 1.61, P=0.02). Homozygosity for the fibrinogen -455A allele was significantly associated with a decreased risk of myocardial infarction (OR 0.66, 95% CI 0.44 to 0.99, P=0.04), whereas the PAI-1 4G4G genotype was significantly associated with increased risk (OR 1.20, 95% CI 1.04 to 1.39, P=0.04).

CONCLUSIONS

Associations between these genetic variations and myocardial infarction were weak or absent. In the absence of clinical implications, our results indicate that screening of patients with myocardial infarction for these genetic variations is not warranted.

Correlation of polymorphisms to coagulation and biochemical risk factors for cardiovascular diseases

Currently, the established risk factors for cardiovascular disease (CVD) are largely environmental in nature. Conflicting studies have suggested that mutations in specific coagulation genes may also provide a genetic basis for CVD risk. We reviewed clinical studies that examined the role of single nucleotide polymorphisms in coagulation and platelet factors, and a biochemical factor to determine if specific genotypes are correlated with patients with a history of arterial thrombotic diseases (acute coronary syndromes or stroke). A meta-analysis was performed on studies for factors II (G20210A variant), V Leiden (G1691A), VII (R353Q), glycoprotein (GP) IIIa receptor (PI(A1/A2)), and methylenetetrahydrofolate reductase (MTHFR, C677T). There was no correlation for factor II or factor V polymorphisms to coronary artery disease (CAD) in 5,607 and 5,431 patients studied, respectively. There was also no correlation for factor II variants and stroke in 3,451 patients studied. For factor V, statistical significance was achieved for the G1691A variant on 3,399 patients with stroke (odds ratio [OR] 1.43, 95% confidence intervals [CI] 1.03 to 1.97). The GP IIIa PI(A1/A2) genotype was associated with increased risk for CAD in 7,920 patients (OR 1.12, 95% CI 1.01 to 1.24), but not for 1,855 patients who had a stroke (OR 0.80, 95% CI 0.62 to 1.04). The combined RQ and RR genotypes of factor VII R353Q were correlated to a reduced risk for CVD in 2,574 patients (OR 0.78, 95% CI 0.65 to 0.93), whereas the QQ genotype had offered more protection (OR 0.53, 95% CI 0.27 to 1.03). The TT homozygous variant of MTHFR was associated with CAD risk in 5,644 patients studied (OR 1.30, 95% CI 1.11 to 1.52) but not for 3,075 patients with stroke. This study shows that for some genes, further studies are unnecessary, whereas for others, no more enrollments are needed. The impact of certain genotypes must be examined in relation to other established risk factors and potentially new therapeutic strategies.