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Background: Amiloride-sensitive epithelial sodium channels (ENaCs) are important candidates in the development of hypertension, which is a major risk factor for stroke. Two single-nucleotide polymorphisms (SNPs) in the gene that encodes the ENac α-subunit (αENaC) have been identified. We evaluated those SNPs for a possible association with ischemic cerebrovascular events (ICEs). Methods and Results: We genotyped 1399 patients with ICEs [median age, 70 years; interquartile range, 58–78 years; 745 (53%) men] and 1076 control individuals without vascular disease [47 (39–58) years; 557 (52%) men] for the SNPs Trp493Arg and Ala663Thr. The SNP frequencies at nucleotide 3977 (Trp493Arg) in the αENaC gene were significantly different in patients and controls. Carriers of 493Arg had a 1.78-fold increased risk (95% confidence interval, 1.02–3.12) for ICEs compared with Trp/Trp carriers. Interaction analysis revealed that the relative risk was even higher in women in the lowest age tertile [adjusted odds ratio, 3.26 (1.10–9.72)]. Conclusions: Carriers of the 493Arg allele are at increased risk for ICEs compared with Trp/Trp carriers. The effect is independent of traditional vascular risk factors and is particularly evident in younger women. The Trp493Arg variant in αENaC may represent an important candidate genetic susceptibility factor in the development of ICEs.

Background: Single-nucleotide polymorphisms (SNPs) in inflammation-related genes have been linked to an increased risk of ischemic stroke. Most of these SNP results have not been replicated, however, and metaanalyses of the effects of inflammation-related genes are rare. We investigated 49 SNPs in 34 genes previously reported to be related to inflammation in our study. We tested 459 patients with acute ischemic stroke or transient ischemic attack and 459 controls individually matched by sex and age. Methods: We studied genetic variation by PCR analysis and subsequent hybridization to linear arrays of sequence-specific oligonucleotides. We used univariate conditional logistic regression analysis to test for associations of conventional vascular risk factors and the SNPs with stroke. Variables showing significant differences (P < 0.05) between cases and controls were included in a multivariate model. ROC curves were plotted to assess the contribution of genetic variation to stroke risk in addition to that of conventional risk factors. Results: Univariate regression analysis revealed 3 SNPs with significant allelic differences between patients and controls, which fulfilled the criteria for further analysis. Only one of these SNPs, the C5 (complement component 5) 2416A>G variant (rs17611), remained significant after the multivariate analysis (odds ratio, 0.585; P = 0.0037). ROC curve analysis revealed no contribution of this genetic variation to stroke risk. Conclusions: We found evidence for an association of the 2416A>G polymorphism in the C5 gene with the risk for ischemic stroke. Our data suggest that the C5 gene particularly influences the risk for patients with microangiopathy.

Background: Epidemiological studies indicate that genetic factors play a role in the risk of stroke, particularly in younger individuals, but the role of single-nucleotide polymorphisms (SNPs) is controversial. We tested the possible association of a number of previously described SNPs with stroke risk. Methods: We investigated the prevalence of 60 polymorphisms located in 35 genes in 450 white patients who suffered an acute stroke or transient ischemic attack before the age of 60 years and in 817 healthy control individuals by a multilocus PCR-based assay. The controls were randomly selected from attendees of a health service program. Genetic variations were detected by hybridization to nylon strips (Roche Molecular Systems) containing detection oligonucleotides for the SNPs. We used P values of Results: Frequencies of all 60 tested SNPs among patients and controls were very similar. No SNP reached an odds ratio of 2, and no association with stroke risk was statistically significant. Conclusions: Our results do not indicate a clinically relevant role of any of the investigated SNPs for stroke risk in individuals hospitalized for ischemic stroke/transient ischemic attack before or at 60 years of age. These results are in accordance with previous metaanalyses showing at most a very modest or no significant effect of these SNPs on stroke risk.

Background: Coagulation factor VII (FVII) plays an important role in the activation of blood coagulation and clot formation. Recent studies have provided evidence for an association between common polymorphic markers in the FVII gene and plasma FVII concentrations. The 353R>Q sequence variation, and 3 common sequence variations in the promoter of the FVII gene—the 10-bp insertion/deletion at position −323 and the −401G>T and −402G>A sequence variations—are well-known determinants of circulating FVII concentrations. Methods: To clarify the role of these sequence variations in the pathogenesis of ischemic stroke, we performed a case–control study with 242 patients with ischemic stroke before the age of 60 years and 239 healthy controls. Results: The −323 insertion/deletion and the 353R>Q and −401G>T sequence variations were in strong linkage disequilibrium, and the resulting haplotypes occurred with equal frequencies in patients and controls. The variant form of FVII (−402G>A) occurred only in combination with the common (wild-type) sequences at all other loci. This haplotype was more frequent in patients than in healthy controls (28% vs 22%). The difference in the prevalence of carriers of this haplotype among patients and controls was statistically significant (P = 0.03; odds ratio = 1.6; 95% confidence interval, 1.1–2.6). Conclusion: According to our results, the FVII −402A allele seems to increase the risk of early ischemic cerebrovascular events, whereas the 353R>Q, G−401T, and −323ins/del sequence variations, which are in close linkage disequilibrium, apparently do not influence the risk of stroke.

Ischemic stroke is a multifactorial disease and a major cause of death and disability throughout the world. Acquired risk factors (e.g., hypertension, cigarette smoking, and diabetes mellitus) account only for ∼69% of the population-attributable risk. Thus, it is likely that other, as yet unidentified, factors contribute to the development of stroke (1). Both epidemiologic and animal-based studies suggest that alterations in a variety of candidate genes, including hemostatic genes, genes controlling homocysteine metabolism, the gene that encodes angiotensin-converting enzyme, and the gene that encodes endothelial nitric oxide synthase, are important in the pathogenesis of ischemic stroke (2)(3). Apparently the genetic influences are polygenic. In addition, ischemic stroke comprises many different phenotypes. According to previous studies, genetic factors seem to have different effects depending on stroke etiology [e.g., lacunar stroke and polymorphisms in the gene encoding interleukin-6 (4)]. In combination with acquired risk factors such as smoking, the presence of one or a combination of several predisposing genes may favor the occurrence of stroke. Cytochrome P-450 (CYP) 2C9 belongs to a large family of heme-containing enzymes that catalyze the oxidation of various drugs and endogenous substrates. CYP2C9 is produced in the liver, is responsible for 50% of the epoxygenase activity in the human liver, and metabolizes a wide variety of clinically important drugs (5). Interestingly, CYP2C isoforms also seem to play a role in the regulation of vascular tone. CYP2C9 is expressed in the endothelium and, via production of endothelium-derived hyperpolarizing factor (EDHF), may cause vasorelaxation as a result of hyperpolarization of vascular smooth muscle cells by activation of Ca2+-activated K+ channels (6). EDHF production seems to be inhibited by NO and/or prostacyclin and has been described as an important regulator of vascular tone under certain pathologic conditions and in certain vascular beds, such as …