Nitric Oxide Synthase Gene Polymorphisms Research Articles

Endothelial nitric oxide synthase and nicotinamide adenosine dinucleotide phosphate oxidase p22phox gene (C242T) polymorphisms and systemic lupus erythematosus in a Chinese Population

Genetic polymorphisms in the endothelial nitric oxide synthase (eNOS) and nicotinamide adenosine dinucleotide phosphate (NADPH) oxidase p22phox are linked with the expression and/or progression of vascular disease. We hypothesized that these polymorphisms may influence the development and/or progression of systemic lupus erythematosus (SLE), given their linkage with vascular disease. DNA from patients with SLE (n = 90) and their age- and sex-matched controls (n = 86) from The Second Xiangya Hospital of Central South University was assessed for eNOS and NADPH oxidase p22phox polymorphisms. These polymorphisms were examined by restriction fragment length polymorphism-polymerase chain reaction. The allele frequency of the NADPH oxidase p22phox gene C242T polymorphisms significantly varied between the SLE patients and the controls. We found no association of the eNOS polymorphism with the development of renal disease. These results indicated that the etiology of patients with SLE is associated with NADPH oxidase p22phox gene C242T polymorphisms. There was no significant increased risk of SLE associated with eNOS polymorphisms in the Chinese population.

Lack of association between endothelial constitutive nitric oxide synthase (ecNOS 4 b/a) gene polymorphism and rheumatic heart disease

Our aim in this work was to explore any possible association between ecNOS 4 b/a polymorphism and rheumatic heart disease (RHD). In this study, leukocyte DNA was extracted from 139 patients with RHD and 79 healthy control children. After amplification by PCR, the products were separated by electrophoresis in 6% polyacrylamide gel and visualized after ethidium bromide staining with UV light. PCR resulted in a 420-bp fragment (ecNOS4b) when five 27-bp repeats were present in intron 4 of the ecNOS gene, a 393-bp product (ecNOS4a) when only four repeats were present, and 420-bp and 393-bp fragments in heterozygous individuals (ecNOS4b/a). ecNOS4b/a genotyping in the control group gave the following results: b/b genotype (77.2%), b/a genotype (21.5%) and a/a genotype (1.3%). The frequencies in RHD group were as follows: b/b genotype (67.6%), b/a genotype (31.7%), and a/a genotype (0.7%). The b allele/a allele ratio was (88%/12%) in the control group and (83.5%/16.5%) in the RHD group. We found no statistical difference in genotype or allele frequency between these groups. The present study is the first to study the association between ecNOS 4b/a gene polymorphism and RHD, and to find a lack of any association between them. Further investigations of this gene polymorphism alone and in combination with other genes should be encouraged.

Endothelial nitric oxide synthase Glu298Asp, 4b/a, and −786T>C gene polymorphisms and the risk of ischemic stroke

Endothelial nitric oxide synthase (eNOS) gene polymorphisms were associated with reduced NO production, and were evaluated as risk factors for ischemic stroke (IS). We investigated the association between eNOS gene -786T>C (promoter), 27-bp repeat 4b/4a (intron 4), and Glu298Asp (exon 7) polymorphisms with IS in 329 IS patients and 444 controls. Glu298Asp and -786T>C genotyping was done by PCR-RFLP, 4b/4a was assessed by PCR-ASA. The contribution of eNOS polymorphisms to IS was analyzed by haplotype and multivariate regression analysis. Higher frequency of 298Asp allele was seen in IS patients (P = 1.2 x 10(-10)), which remained independently associated with IS on multivariate analysis after controlling for traditional cerebrovascular risk factors. Allele and genotype distribution of 4b/4a and -786T>C polymorphisms were comparable between patient and controls. Significantly higher prevalence of 298Asp/4b/-786T and 298Asp/4b/-786C haplotypes were seen in IS cases, thus conferring a disease susceptibility nature to these haplotypes. Multivariate regression analysis confirmed the association of 298Asp/4b/-786T and 298Asp/4b/-786C haplotypes, and in addition identified 298Asp/4a/-786T haplotype to be independently associated with IS, after controlling for traditional cerebrovascular risk factors. Genetic variation at the eNOS locus represent genetic risk factor for increased susceptibility to IS.

T-786C Polymorphism in Promoter of eNOS Gene as Genetic Risk Factor in Patients With Erectile Dysfunction in Turkish Population

To investigate the effect of 2 endothelial nitric oxide synthase gene polymorphisms, namely, variable number of 27-bp tandem repeats in intron 4 and T-786C in the promoter region, on the susceptibility to erectile dysfunction (ED) in Turkish population. A total of 72 patients with ED (mean age 54.3 +/- 9.2 years) diagnosed by Doppler ultrasonography and 71 healthy controls (mean age 55.4 +/- 8.2 years) were analyzed. Genotypes were determined through polymerase chain reaction with or without restriction endonuclease digestions. Genotype distribution for CC genotype of T-786C polymorphism in promoter was significantly different between patients with ED and controls, the genotype frequency being 31.9% and 12.7%, respectively (P = .019). The univariate odds ratio (OR) associated with CC alleles revealed 3 times increased risk for ED (OR = 3.2; 95% confidence interval [CI], 1.4-7.6; P = .006). The risk also holds when excluding patients with hypertension and diabetes mellitus (P = .012, OR = 3.1; 95% CI, 1.2-7.7) as well as obesity (P = .05, OR = 4; 95% CI, 1.05-15.3). Patients with CC genotype of promoter present earlier symptoms of ED (51.7%) compared with controls (10.7%) (P <.001). No significant correlation was observed with variable number of tandem repeats in intron 4 and with the type of vascular insufficiency. The CC genotype of T-786C polymorphism in the promoter of eNOS gene is associated with increased risk of ED in Turkish population. Earlier onset of ED with CC genotype suggests that CC allele is an independent risk factor for endothelial dysfunction in the absence of other risk factors (hypertension, diabetes mellitus, obesity). An impaired NO production because of CC alleles may account for pathophysiology of ED.

Distribution of Endothelial Nitric Oxide Synthase Gene Polymorphisms in Turkish Population

Nitric oxide (NO) is the major mediator in the regulation of vascular homeostasis. It is synthesized by endothelium from arginine with the catalytic help of endothelial NO synthase (eNOS). Polymorphisms...

Lack of association between endothelial constitutive nitric oxide synthase (ecNOS 4 b/a) gene polymorphism and rheumatic heart disease

Our aim in this work was to explore any possible association between ecNOS 4 b/a polymorphism and rheumatic heart disease (RHD). In this study, leukocyte DNA was extracted from 139 patients with RHD and 79 healthy control children. After amplification by PCR, the products were separated by electrophoresis in 6% polyacrylamide gel and visualized after ethidium bromide staining with UV light. PCR resulted in a 420-bp fragment (ecNOS4b) when five 27-bp repeats were present in intron 4 of the ecNOS gene, a 393-bp product (ecNOS4a)when only four repeats were present, and 420-bp and 393-bp fragments in heterozygous individuals (ecNOS4b/a). ecNOS4b/a genotyping in the control group gave the following results: b/b genotype (77.2%), b/a genotype(21.5%) and a/a genotype (1.3%). The frequencies in RHD group were as follows: b/b genotype (67.6%), b/a genotype (31.7%), and a/a genotype (0.7%). The b allele/a allele ratio was (88%/12%) in the control group and (83.5%/16.5%) in the RHD group. We found no statistical difference in genotype or allele frequency between these groups. The present study is the first to study the association between ecNOS 4b/a gene polymorphism and RHD, and to find a lack of any association between them. Further investigations of this gene polymorphism alone and in combination with other genes should be encouraged.

Relationships between endothelial nitric oxide synthase gene polymorphisms and osteoporosis in postmenopausal women

To investigate the relationships between endothelial nitric oxide synthases (eNOS) G894T and 27 bp-variable number tandem repeat (VNTR) gene polymorphisms and osteoporosis in the postmenopausal women of Chinese Han nationality. In the present study, 281 postmenopausal women from Xi'an urban area in West China were recruited, and divided into osteoporosis, osteopenia, and normal groups according to the diagnostic criteria of osteoporosis proposed by World Health Organization (WHO). The bone mineral density (BMD) values of lumbar vertebrae and left hips were determined by QDR-2000 dual energy X-ray absorptiometry. Blood samples were tested for plasma biochemical indicators including testosterone, estradiol, calcitonin, osteocalcin, and procollagen type I amino-terminal propeptide by enzyme-linked immunosorbent assay (ELISA), tartrate-resistant acid phosphatase by spectrophotometric method, and the content of nitric oxide by Griess method. Genome DNA was extracted from whole blood, and G894T polymorphism of eNOS gene was analyzed by using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method and 27 bp-VNTR polymorphism of eNOS gene was genotyped by PCR method. Then the relationships between genotypes and biochemical indicators, genotypes and osteoporosis, and haplotypes and osteoporosis were analyzed. The average BMD values of the femoral neck, ward's triangle and lumbar vertebrae 1-4 (L1-L4) in the subjects with T/T genotype in eNOS G894T locus were significantly higher than those in the subjects with G/T and G/G genotypes (P<0.05). The average BMD of the femoral neck in the subjects with a/a genotype of eNOS 27 bp-VNTR locus was evidently higher than that in the subjects with b/b genotype (P<0.05). The plasma testosterone and osteocalcin concentrations in the subjects of eNOS G894T G/T genotype were evidently higher than those in the subjects of other genotypes (P<0.05); the plasma estradiol concentration in the subjects of eNOS 27 bp-VNTR a/a genotype was obviously higher than that in the subjects of b/b genotype (P<0.01). eNOS G/G homozygous frequencies in osteoporosis women, osteopenia women, and normal women were 85.37%, 76.38%, and 83.87%, respectively (P>0.05). 0% osteoporosis woman, 0.79% osteopenia women, and 3.23% normal women were eNOS a/a homozygous (P<0.05). The frequencies of eNOS 27 bp-VNTR a allele were 5.33% in the osteoporosis group, 10.24% in the osteopenia group, and 16.13% in the normal group (P<0.05, odds ratio (OR)=0.29, 95% confidence interval (CI)=0.11-0.77), suggesting that a/a genotype and a allele might have protective effects on osteoporosis. The haplotype analysis showed that G-b was 87.7% (214/244) in the osteoporosis group (P<0.05, OR=2.48, 95% CI=1.18-5.18). G-a was 5.3% (13/244) in the osteoporosis group (P<0.05, OR=0.29, 95% CI=0.11-0.77). G-b was a risk factor for osteoporosis, and G-a a protective factor. eNOS G894T G/T genotype influenced the plasma testosterone and osteocalcin concentrations, and T/T genotype influenced BMD. eNOS 27 bp-VNTR a/a genotype increased plasma estradiol concentration to have a protective effect on osteoporosis.

ENOS G894T Polymorphism and Abdominal Aortic Aneurysms

The genetic risk factors that contribute to the risk of developing abdominal aortic aneurysm (AAA) are poorly understood. We assessed the association of endothelial nitric oxide synthase (eNOS) gene polymorphism with AAA. eNOS gene polymorphism of 61 patients with AAA and 62 control participants were analyzed by polymerase chain reaction (PCR)-restriction technique. eNOS G894 homozygote T/T genotype polymorphism and 894T allele frequency in patients with AAA were significantly higher than those of the control participants (P = .01, P = .03). Among patients with AAA, the eNOS G894 T/T polymorphism and 894T allele frequency were associated with larger AAAs. The current study, in a small group of participants, showed a relationship between eNOS G894T polymorphism and AAA.

Lack of Association Between Matrix Metalloproteinase-9 and Endothelial Nitric Oxide Synthase Gene Polymorphisms and Coronary Artery Disease in Turkish Population

Polymorphic variants of genes encoding proteins involved in vascular remodeling may genetically diverge among different populations and play a role in the susceptibility to the coronary artery disease (CAD). MMP-9-1562 C/T (rs3918242), eNOS T-786C (rs2070744), and Glu298Asp (rs1799983) are among the most studied of these polymorphisms. The aim of this study was to determine the relationship between CAD and these polymorphisms in the Turkish population. The analysis included 146 CAD+ and 122 CAD- individuals. Genomic DNA was isolated from whole blood and genotyping was performed by the PCR-RFLP method. No significant associations were found between -1562 C/T (p = 0.557), Glu298Asp (p = 0.432), and -786 T/C (p = 0.055) polymorphisms and CAD. The distribution of each haplotype also did not differ between CAD+ and the CAD- samples (p > 0.05). The present investigation is the first to study an association between -1562 C/T polymorphism and CAD in the Turkish population. In conclusion, no appreciable differences between CAD+ and CAD- samples were found in terms of polymorphisms mentioned above.

Endothelial nitric oxide synthase gene polymorphisms are not associated with recurrent aphthous stomatitis

Objective Recurrent aphthous stomatitis (RAS) is a common ulcerative disease of the oral mucosa. Recurrent oral aphthous ulceration is the most common and consistent feature of the more serious and systemic Behçet's disease (BD). Association of endothelial nitric oxide synthase (eNOS) gene polymorphisms with BD have been reported in different populations. This study aims to investigate if there is an association between these polymorphisms and RAS. Methods A case–control association study using 91 Caucasoid RAS patients and 91 ethnically matched systemically healthy controls were genotyped for the −786 and 894 eNOS single nucleotide polymorphisms (SNPs) and a variable number of tandem repeat (VNTR) polymorphism. Chi-square analysis was used to compare the allele and genotype frequencies. Results No significant difference was found in the distribution of allele and genotype frequencies of the −786 and +894 polymorphisms or the VNTR polymorphism between cases and controls. Conclusion eNOS gene polymorphisms associated with BD are not associated with RAS. This suggests that the oral ulceration common to both conditions may have a different underlying genetic aetiology. Although our data suggests that RAS does not have an association with eNOS, it is still possible that nitric oxide is involved in the disease process. This could still occur through localised and inflammation driven regulation by iNOS.

Toll-like receptor 4 and inducible nitric oxide synthase gene polymorphisms are associated with Type 2 diabetes

Background The toll-like receptor 4 (TLR4) and inducible nitric oxide synthase are proteins from the innate immune system that, when activated, can induce insulin resistance. Polymorphisms in these genes, TLR4 and NOS2, respectively, could affect the immune response, as well as the prevalence of Type 2 diabetes (T2DM). Objective The aim of the present study was to investigate the contribution of four polymorphisms (two from TLR4 and two from NOS2) to susceptibility to T2DM in a southeast Brazilian population. Design A total of 211 patients with T2DM and 200 unrelated controls were genotyped for the Asp299Gly and Thr399Ile polymorphisms of the TLR4 gene and for the insertion (I)/deletion (D) AAAT and (CCTTT)n polymorphisms of the NOS2 promoter gene. Results With regard to the NOS2 promoter region, the data showed that the I allele of the I/D AAAT polymorphism was more prevalent in the T2DM group and that the L/L genotype of the (CCTTT)n polymorphism was also more frequent in the same group. In contrast, the 299Gly allele and the 399Ile allele from the Asp299Gly and Thr399Ile TLR4 gene polymorphisms, respectively, were associated with protection of T2DM. It is believed that the persistence of these genetic variations in human populations may be indicative of a selective advantage in the face of different environmental pressures. Conclusions Genetic variations in the NOS2 gene promoter and TLR4 coding sequence may lead to deleterious and protective effects, respectively, arising from altered function of the innate immune system in patients with T2DM.

Angiotensin-converting enzyme gene and endothelial nitric oxide synthase gene polymorphisms in Behçet’s disease with or without ocular involvement

The association of known ACE gene and eNOS gene polymorphisms with BD in a group of Turkish patients with or without ocular involvement has been investigated. The ACE and eNOS gene polymorphisms were investigated in 73 BD patients and 90 controls. The distrubition of "DD", "ID" and "II" genotypes of the ACE gene were 32 (43.8%), 29 (39.8%) and 12 (16.4%) for BD patients and 32 (35.5%), 35 (38.9%) and 23 (25.6%) for healthy controls. There was no significant difference between the groups (p = 0.140, OR 1.44, CI 0.90-2.30). When Behçet patients with ocular involvement were compared to the control group, statistical significance was found (p = 0.049, OR 2.18, CI 1.00-4.81). The "bb", "ba", and "aa" genotype frequencies of the eNOS gene were 48 (65.8%), 23 (31.5%), and 2 (2.7%) for patients with BD and 75 (83.3%), 15 (16.7%), and 0 (0%) for healthy controls, respectively. The significant difference found in allelic frequencies between the two groups (p = 0.011, OR 2.32, CI 1.11-4.87). When Behçet patients with ocular involvement were compared, sharper statistical significance was found (p = 0.001,OR 4.61,CI 1.85-11.52). The ACE gene polymorphism does not play a role in the pathogenesis of BD. The findings of the eNOS gene polymorphisms confirmed the significant association with BD and even more in patients with ocular involvement.

Endothelial nitric oxide synthase gene polymorphisms and the renal hemodynamic response to L-arginine

Nitric oxide is generated from L-arginine by nitric oxide synthase (NOS), an enzyme that exists in several isoforms. Some studies found that a polymorphism (G894T) in the endothelial NOS gene was associated with decreased nitric oxide bioactivity and vascular complications. However, it is not known whether the enzyme had a reduced activity. Here we measured the effect of an infusion of L-arginine on renal hemodynamic function in subjects segregated by the presence or absence of the T allele. If this polymorphism represented a functional variant, subjects with the GT/TT form should exhibit a blunted renal hemodynamic response to L-arginine compared to those with a GG allele. All subjects were given a diet controlled for sodium and protein intake. GG subjects had lower mean arterial pressure and an augmented glomerular filtration rate at baseline. In response to a graded L-arginine infusion, this group had significant changes in effective renal plasma flow, glomerular filtration rate, filtration fraction, renal vascular resistance, and renal blood flow. The renal response to L-arginine in GT/TT subjects was blunted. Circulating cGMP levels and endothelial NOS mRNA expression, measured in skin biopsies by real-time PCR, did not differ between the groups. Our study shows that the G894T allele of endothelial NOS is associated with a blunted response to L-arginine, suggesting this polymorphism may be a functional variant in humans.

Nitric oxide synthase gene polymorphisms in children with minimal change nephrotic syndrome

Nitric oxide (NO) attenuates many functions within the kidney, and all NO synthase (NOS) isoforms are constitutively expressed in the kidney. But the exact role of NO in renal diseases is still debatable. The aim of the present study was to investigate endothelial (eNOS), and neuronal (nNOS) NOS gene polymorphisms in children with minimal change nephrotic syndrome (MCNS). Eighty-six Turkish children with clinical MCNS, ranging in age from 2 to 10 years, were compared with 114 healthy age- and sex-matched controls. The glu 298 Asp (G/T) polymorphism of the eNOS, and C276T (C/T) polymorphism of nNOS genes were genotyped using polymerase chain reaction. The distribution of GG, TG, and TT genotypes for eNOS was 52%, 33% and 15% in MCNS compared with 61%, 26% and 13% in the controls (P > 0.05). The distribution of CC, TC, and TT genotypes for nNOS was 16%, 66% and 18% in MCNS compared with 10%, 43% and 47% in the controls. TT genotype distribution of nNOS was found to be lower in patients (P = 0.003). The eNOS and nNOS gene polymorphisms were not associated with gender, positive family history, frequency of relapses, or response to steroid. The present study is the first to investigate eNOS and nNOS gene polymorphisms in children with MCNS. The nNOS gene polymorphism may be associated with MCNS in children, but further studies in a larger population with different glomerular diseases are needed to confirm the results.

Nitric oxide synthase gene polymorphisms and prostate cancer risk

Nitric oxide (NO) induces cytotoxicity and angiogenesis, and may play a role in prostate carcinogenesis, potentially modulated by environmental exposures. We evaluated the association of prostate cancer with genetic polymorphisms in two genes related to intracellular NO: NOS2A [inducible nitric oxide synthase (NOS); -2892T>C, Ex16 + 14C>T (S608L), IVS16 + 88T>G and IVS20 + 524G>A] and NOS3 [endothelial NOS; IVS1-762C>T, Ex7-43C>T (D258D), IVS7-26A>G, Ex8-63G>T (E298D) and IVS15-62G>T]. Prostate cancer cases (n = 1320) from the screening arm of the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial were frequency matched to controls (n = 1842), by age, race, time since initial screening and year of blood draw. An antioxidant score [range 3-12; low (3-7) versus high (8-12)] was created by summing the quartile levels of vitamin E, beta-carotene and lycopene, which were coded from 1 to 4, respectively. The global tests for all eight single-nucleotide polymorphisms (SNPs) (excluding NOS2A-2892T>C, with low minor allele frequency) were statistically significant for prostate cancer (P = 0.005), especially for aggressive cancer (stage III-IV or Gleason score > or = 7) (P = 0.01). The NOS2A IVS16 + 88 GT/TT was associated with increased prostate cancer risk (odds ratio = 1.24, 95% confidence interval = 1.00-1.54), whereas the IVS20 + 524 AG/GG was associated with decreased risk (0.77, 0.66-0.90). The NOS3 IVS7-26GG was associated with increased prostate cancer risk (1.33, 1.07-1.64). All these SNPs showed significant associations with aggressive cancer and not for non-aggressive cancer. In the evaluation of effect modification, the effect of the NOS2A IVS16 + 88 GT/TT on aggressive cancer was stronger among subjects with higher antioxidant intake (1.61, 1.18-2.19; P(interaction) = 0.01). Our results suggest that NOS gene polymorphisms are genetic susceptibility factors for aggressive prostate cancer.

Protective role of 27bp repeat polymorphism in intron 4 of eNOS gene in lacunar infarction

Association of the three potential endothelial nitric oxide synthase gene (eNOS) polymorphisms (T-786C in promoter region, G894T in exon 7 and tandem 27-bp repeats in intron 4) with an increased risk of lacunar infarction (LI) were investigated. Genotypes of 70 patients and 81 healthy controls were determined through PCR with or without RFLP. Flow-mediated dilatation (FMD) was performed to assess endothelial-dependent vasodilatation, whereas the endothelial-independent vasodilatation was assessed with nitroglycerin (NTG). Genotype distribution was significantly different between LI patients and controls for intron 4aa (alleles for four repeats), genotype frequency being 1.4% and 16.0%, respectively (odds ratio for additive effect, 0.47; 95% CI, 0.28–0.81; p=0.006). Haplotypes with the intron 4aa polymorphism were significantly higher in controls when compared with the LI group (p=0.001). Diminished FMD but normal NTG response confirmed that patients with LI have generalized endothelial dysfunction. Intron 4aa genotype of eNOS gene seems to be protective for isolated LI and the effect was potentiated by the absence of 786C polymorphism in any allele of the promoter region.

Endothelial nitric oxide synthase (e-NOS) gene polymorphism (Glu298Asp) and pulmonary hypertension in children with congenital heart diseases

Endothelial nitric oxide synthase (e-NOS) gene polymorphism (Glu298Asp) and pulmonary hypertension in children with congenital heart diseases

Association between 894G&gt;T endothelial nitric oxide synthase gene polymorphisms and metabolic syndrome

Metabolic syndrome (MS) is a cluster of cardiovascular risk factors such as hypertension, dyslipidemia, obesity and type II diabetes. Here, we performed a case-control study analyzing the association between 894G>T endothelial nitric oxide synthase gene polymorphism (NOS3) and MS in 616 subjects. Genotype frequencies were TT= 9.3%, GG= 37.2 and TG= 53.6% and the allelic frequencies were T=0.36 and G= 0.64. We observed a higher TT genotype frequency in the male MS group than control subjects (p=0.02), independent of other variables. We found an association between hypertension and TT genotype in females. Our data suggests that 894G>T plays a significant role in the mechanistic interaction between metabolic risk such as hypertension and MS, although sex-related differences may exist.

Abstract 2398: Polymorphisms of Angiotensin Converting Enzyme and Endothelial Nitric Oxide Synthase Genes Act Synergistically to Increase the Risk of Cardiovascular Events in Patients with Hypertrophic Cardiomyopathy

Background: Patients with hypertrophic cardiomyopathy (HCM) have a small left ventricular cavity size due to hypertrophy. Therefore, reduction of venous return and intravascular volume in patients with HCM leads to low cardiac output and hypotension. We reported that the angiotensin converting enzyme insertion/insertion (ACE I/I) genotype, which leads to inhibitory renin-angiotensin system, is a significant risk factor for cardiovascular events (CE) in patients with HCM. Recently, the endothelial nitric oxide synthase (eNOS) gene polymorphism (Glu298Asp), which plays an important role in the modulation of cardiovascular physiology, is reported to be associated with heart diseases. Methods and Results: Genotyping at these loci was performed in 150 patients with HCM. This study design was a nested case-control study. The cardiovascular events were defined as cardiac death and hospitalization for stroke or congestive heart failure. Patients were divided into two groups: group A of 44 patients (29%) with one or more history of the cardiovascular events and group B of 106 patients (71%) without history of the cardiovascular events. Logistic-regression methods were used to determine the potential effect of each genotype and the interaction between them on the risk of CE. The odds ratio for cardiovascular events among persons who had ACE I/I genotype as compared with those with the other ACE genotypes was 2.5 (P &lt; 0.01). In a dominant Asp allele model of the eNOS gene polymorphism, there was a significant difference in genotypes between the two groups (p &lt; 0.01). In addition, there was a marked increase in the risk of CE among persons who were homozygous for both genotypes (ACE I/I and eNOS 298Glu/Glu) (odds ratio, 2.7, P &lt; 0.01). Conclusion: The ACE I/I and eNOS 298Glu/Glu act synergistically to increase the risk of CE in patients with HCM. Genotyping at these two loci may be a useful approach for identification of persons with HCM at risk for CE.

Lack of association between endothelial nitric oxide synthase gene polymorphisms and risk of premature coronary artery disease in the Greek population

Objective — Genetic polymorphisms in the gene for endothelial nitric oxide synthase have been considered as potential risk factors for the development of coronary artery disease in some populations.Methods — We studied two polymorphisms of the NOS3 gene, the VNTR in intron 4 (4VNTR) and the Glu298Asp polymorphism in exon 7, in relation to the existence of premature coronary artery disease and the occurrence of myocardial infarction. A total number of 370 individuals of the Greek population was examined by PCR-RFLP method. The patient group consisted of 209 subjects, aged less than 58 years presenting symptomatic coronary artery disease, documented by coronary angiography.Results — The frequencies for bb, ab and aa genotypes of 4VNTR polymorphism were 0.67, 0.29, 0.04, respectively, for the patient group and 0.73, 0.24, 0.03 for the control group. The frequencies for GG (Glu/Glu), GT (Glu/Asp), TT (Asp/Asp) of the Glu298Asp polymorphism were 0.52, 0.41, 0.07, respectively, in patients compared to 0.47, 0.46, 0.07, in control subjects. Statistical analysis indicated that there are no significant differences in the frequencies of the genotypes between patients and control subjects for both polymorphisms. The combined analysis of the two polymorphisms indicated no synergistic effect of the a and T alleles on coronary artery disease.Conclusions — We have found no evidence for association between the a allele of the 4VNTR polymorphism, or the T allele of Glu298Asp polymorphism and the risk for premature coronary artery disease or occurrence of myocardial infarction. Furthermore, no synergistic contribution of these polymorphisms to the development of premature coronary artery disease has been observed.