Angiotensin-converting enzyme I/D gene polymorphisms and effects of left ventricular hypertrophy in Turkish myocardial infarction patients

OBJECTIVE: Since the initial report of the association of the deletion/insertion (D/I) polymorphism in the gene for angiotensin-converting enzyme (ACE) with myocardial infarction (MI), there has been considerable controversy. Some have found the D allele to be associated with MI, coronary heart disease (CHD) or other cardiac pathologies, while others have not. In view of the clinical importance of the ACE as a major marker of cardiovascular diseases, we investigated the I/D polymorphism of the ACE gene in Turkish patients with acute myocardial infarction in comparison with control subjects. METHODS AND RESULTS: Polymerase chain reaction, and agarose gel electrophoresis techniques were used to determine the ACE genotype in 214 subjects. The frequencies of ACE D and ACE I allele among the patients with acute myocardial infarction were 65.54% and 36.45% and in the control subjects 57.62% and 42.37%, respectively. ACE DD genotypes were found higher in patients with left ventricular hypertrophy (LVH) than without LVH (55.6% vs. 37.7%; X2: 2.534, p > 0.05). CONCLUSIONS: The ACE D allele is more frequent in patients with acute myocardial infarction than in controls. Moreover ACE DD genotype might be associated with an increased risk of left ventricular hypertrophy.     

Angiotensin converting enzyme gene polymorphisms and coronary risk in a Portuguese population]

BACKGROUND: A family history of coronary heart disease (CHD) is a strong risk marker for the disease, independently of classical risk factors. It could be decoded by recognizing the polymorphisms associated with increased risk. Renin-angiotensin system genes are candidate genes in CHD and the deletion allele of the angiotensin converting enzyme (ACE) has been reported as deleterious. However, there is disagreement as to the role of the insertion/deletion polymorphism of the ACE gene in coronary risk. AIM: To evaluate whether ACE gene polymorphisms constitute a CHD risk factor. METHODS: We conducted a population-based case-control study of 301 subjects with a history of myocardial infarction or angiographic evidence of coronary heart disease and 510 age- and gender-matched controls, without CHD, living in a region with high CHD mortality rates. Blood samples were taken, DNA extracted and genotypes determined by the polymerase chain reaction (PCR). Amplification products were identified by agarose gel electrophoresis. STATISTICAL ANALYSIS: The Data were evaluated by SPSS for Windows, using the Student's t test, the chi-square test, odds ratios and 95% confidence intervals. RESULTS: The prevalence of the DD, ID and II genotype was 41.2%, 46.3%, 12.5% in the cases and 28.1%, 55.2% and 16.7% in the control group. The frequency of the DD genotype was significantly higher in the cases than in the controls (41.2% vs. 28.1%, odds ratio 1.79, 95% CI 1.31 to 2.4, p < 0.0001). By contrast, the ID and II genotypes' prevalence was higher in the control group (55.2% vs. 46.3%, p = 0.002 and 16.7 vs. 12.5%, p = NS, respectively) compared to the case group. CONCLUSIONS: This study clearly shows that the ACE DD polymorphism is strongly linked to CHD, and if our data are confirmed in a larger population sample, more aggressive vascular prevention could be justified in patients carrying the DD genotype.     

Angiotensin-Converting Enzyme Gene Polymorphism and Plasminogen Activator Inhibitor 1 Levels in Subjects with Cerebral Infarction

It has been suggested that the insertion/deletion (I/D) polymorphism of the angiotensin-converting enzyme (ACE) gene is an independent risk factor for coronary artery disease, but its relation to cerebral infarction is still controversial. Plasminogen activator inhibitor 1 (PAI-1) is also a predictor of risk of atherothrombotic disease. In this study we investigated the association of the ACE gene polymorphism and plasma PAI-1 levels in subjects with cerebral infarction. We evaluated the genotype of the ACE gene in 26 subjects with and 28 subjects without a history of ischemic stroke. The ACE genotype was analyzed by the polymerase chain reaction. Plasma PAI-1 antigen levels were measured by ELISA. There were no differences in accepted risk factors between the groups with or without cerebral infarction. However, the frequency of the D allele was significantly higher in subjects with cerebral infarction (0.63) than in those without infarction (0.39) (² = 6.306, P = 0.012). The frequency of the DD genotype of the ACE gene was also significantly higher in subjects with than in those without cerebral infarction (DD: 46.2%, ID: 34.6%, II: 19.2% vs. DD: 14.3%, ID: 50.0%, II: 35.7%, ² = 6.689, P = 0.035). Plasma PAI-1 levels were not significantly different between groups with and without cerebral infarction. There was no association between the ACE genotype and PAI-1 levels. The DD genotype of the ACE gene is associated with cerebral infarction, which is independent of plasma PAI-1 level.     

Lower mortality in patients with the DD genotype of the angiotensin-converting enzyme gene after acute myocardial infarction.

OBJECTIVE: The angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism has been associated with different serum ACE concentrations and cardiac ACE activity. We assessed whether the ACE gene I/D polymorphism influenced cardiac mortality in Japanese patients with acute myocardial infarction. METHODS AND RESULTS: The ACE gene I/D polymorphism was determined in 441 consecutive patients with a first myocardial infarction.There were 69 patients (16%) with the DD genotype, 194 patients (44%) with the ID genotype, and 178 patients (40%) with the II genotype. During a mean follow-up of 9.4 months, there were 49 cardiac deaths (DD, n = 4; ID, n = 26; II, n = 19).The DD genotype was significantly associated with a lower mortality than the other genotypes (p = 0.0363) by Cox regression analysis adjusted for age, sex, site of myocardial infarction, Killip functional class, reperfusion therapy during acute phase, ACE inhibitor use, and beta-blocker use. CONCLUSIONS: In a selected cohort of Japanese patients, the DD genotype was associated with a significantly lower cardiac mortality after a first myocardial infarction.     

The p22 phox A640G gene polymorphism but not the C242T gene variation is associated with coronary heart disease in younger individuals.

BACKGROUND: Most recently, evidence has been presented that the NADH/NADPH oxidase p22 phox C242T, but not the A640G gene polymorphism is associated with a reduced risk of coronary artery disease (CAD). METHODS AND RESULTS: We analysed the relationships of both p22 phox gene polymorphisms to CAD in 2205 male Caucasians whose coronary anatomy was defined by means of coronary angiography. In the total population and in high and low risk groups the relative frequencies of the C242T alleles were essentially the same in patients without or with CAD and in individuals without or with myocardial infarction. In contrast, the G allele of the A640G polymorphism was significantly more frequent in subjects without CAD than in patients with CAD (Odds ratio (OR) 0.74 (0.57-0.98); P = 0.038 in multiple logistic regression (MLR)). Correspondingly, the AA genotype of A640G was preferentially found in patients with CAD. These associations did not disappear when the analyses were corrected for multiple comparisons for other gene polymorphisms (ACE I/D gene variation, angiotensinogen T174M and M235T gene polymorphisms, AT1 receptor gene variation, phox C242T gene polymorphism, paraoxonase PON54 and PON191 gene variations) (2p = 0.01 in MLR for the presence of CAD; 2p = 0.039 in multiple regression for the extent of CAD). The association of the A640G gene variation with the presence and extent of CAD was not only identified in the total sample, but was even stronger in various high risk subpopulations of younger individuals (e.g. with hypertension with or without increased apolipoprotein B plasma levels). CONCLUSIONS: Our observations allow the assumption that the p22 phox A640G gene polymorphism is independently associated with the presence and extent of coronary artery disease.     

Analysis of the postulated interaction between the angiotensin II sub-type 1 receptor gene A1166C polymorphism and the insertion/deletion polymorphism of the angiotensin converting enzyme gene on risk of myocardial infarction

A synergistic interaction between the insertion/deletion (I/D) polymorphism within the angiotensin-converting enzyme (ACE) gene and an A/C transversion at nucleotide position 1166 within the angiotensin II sub-type 1 receptor (AT1R) gene on risk of myocardial infarction has been reported. The risk associated with the ACE DD genotype increased with the number of AT1R C alleles present. To investigate this further, ACE I/D and AT1R A1166C genotypes were determined in 541 cases recruited at the time of infarction and 507 population-based controls. There was no difference in either the genotype distribution or allele frequencies between cases and controls for either the ACE polymorphism (P=0.48 and 0.35 respectively) or the AT1R polymorphism (P=0.35 and 0.21 respectively). Odds ratios for risk of MI associated with the ACE DD and AT1R CC genotypes were 1.09 (95% CI, 0.82-1.45) and 1.06 (0.67-1.68) respectively. 3.1% of cases versus 3.6% of controls were homozygous for both the D and C alleles (P=0.71). There was no increase in risk associated with the DD genotype in the presence of either one or two AT1R C alleles in the whole cohorts (OR 0.99, 95% CI 0.65-1.51 and 0.76, 95% CI 0.30-1.88, respectively) nor in sub-groups defined by specific risk factors. In conclusion, no evidence was found to support any interaction between the ACE gene I/D polymorphism and the ATIR gene A1166C transversion in determining the risk of myocardial infarction in the population studied.     

NAD(P)H氧化酶p22phox亚基C242T基因多态性与缺血性脑血管病的关系

目的:探讨在中国人群中NAD(P)H氧化酶p22phox亚基C242T多态性与缺血性脑血管病(ICVD)的相关性。方法:共收集了112例ICVD患者(TIA36例,脑梗死76例)和105例对照者,用聚合酶链反应和限制性片段长度多态性分析(PCR-RFLP)的方法确定其基因型。结果:ICVD组和对照组的TC基因型频率分别为0.152和0.057,未发现有TT基因型。ICVD组的TC基因型频率显著高于对照组(P=0.024,OR2.95,95％CI 1.12-7.81)。ICVD亚组间的分析显示,TIA与对照组之间CT基因型频率无明显差异,而脑梗死与对照组则有显著差异。结论:NAD(P)H氧化酶p22phox亚基C242T多态性可能是脑梗死的一个危险因素。     

Renin-angiotensin system gene polymorphisms: assessment of the risk of coronary heart disease

BACKGROUND: Renin-angiotensin system genes are candidate genes in cardiovascular system diseases. Angiotensinconverting enzyme (ACE), angiotensinogen (AGT) and angiotensin II type 1 receptor (AT1R) gene polymorphisms are considered risk factors in coronary heart disease (CHD). AIM: To evaluate the involvement of the ACE, AGT and AT1R genetic variants in predisposition to CHD as well as their association with other known risk factors. METHODS: The study included 400 male subjects (200 with CHD and 200 healthy individuals). Genotypes were determined by a polymerase chain reaction (PCR). For the AGT and AT1R genes a restriction analysis of the PCR product was performed. The allele frequency and genotype distribution were compared between groups. RESULTS: The allele and genotype frequencies of the ACE gene were similar in both groups, however, a significantly higher frequency of the DD genotype was observed in the presence of hyperlipidemia (39% vs 24% in non-hyperlipidemic subjects, p<0.01). The AGT gene polymorphism was associated with the development of CHD. The T allele was significantly more frequent in patients than in the control group (55% vs 44%, p<0.05). The heterozygous MT genotype was observed in 61% of patients compared to 40% in the controls (p<0.05). The A1166C polymorphism of the AT1R gene was also associated with CHD as well as with age at the onset of disease. The frequency of the C allele was 29% compared to 21% in the control group (p<0.01) and the frequency of the CC homozygote was almost three times higher in patients. CONCLUSIONS: There is an association between molecular variants of the angiotensinogen and angiotensin II type 1 receptor and increased risk of CHD. The DD genotype of the ACE gene polymorphism and the TT genotype of the AGT gene polymorphism were significantly more frequent in patients with hyperlipidemia. The TT genotype of the AGT gene M235T polymorphism was associated with an increased risk of CHD and myocardial infarction only in smokers.     

CE基因多态性及其血清水平与心肌梗死的关系

目的　探讨血管紧张素转换酶(ACE)基因插入/缺失(I/D)多态性及其血清水平与老年心肌梗死的关系。方法　应用聚合酶链反应(PCR)方法检测60岁以上心肌梗死患者35例及正常对照者48例的ACE基因。结果　老年心肌梗死组ACE基因中缺失型(DD型)分布(60%)明显高于正常对照组(29.17%)(P＜0.05),缺失型(D型)等位基因频率(74.29%)也明显高于对照组(51.05%)(P＜0.05)。DD型血清ACE水平明显高于II型(P＜0.001)。结论　ACE基因缺失型及高血清ACE水平可能是老年人心肌梗死的一个重要危险因素。     

冠心病患者血管紧张素转换酶基因多态性及其与血清血管紧张素转换酶水平的关系

为研究冠心病患者血管紧张素转换酶（ACE）基因插入／缺失（I／D）多态性分布及其与血清ACE水平的相关性，应用多聚酶链反应方法测定了61例冠心病患者和63例健康人群的ACE基因I／D多态性，并采用微量比色法测定其血清ACE水平。结果发现，冠心病患者ACE基因DD型出现频率显著高于对照组，且DD基因型者具有较高的血清ACE水平。提示ACE基因I／D多态性与血清ACE水平密切相关，DD型ACE基因可能是中国人冠心病发病的独立危险因子。     

冠心病患者血管紧张素转换酶基因多态性及其与血清血管紧张素转换酶水平的关系

为研究冠心病患者血管紧张素转换酶（ＡＣＥ），基因插入／缺失（Ｉ／Ｄ）多态性分布及其血清ＡＣＥ水平的相关性，应用多聚酶链反应方法测定了６１例冠心病患者和６３例健康人群的ＡＣＥ水平，结果发现，冠心病患者ＡＣＥ基因ＤＤ型出现频率显著对照组，且ＤＤ基因型者具有较高的血清ＡＣＥ水平，提示，ＡＣＥ基因Ｉ／Ｄ多态性与血清ＡＣＥ水平密切相关，ＤＤ型ＡＣＥ基因可能是中国人冠心病发病的独立危险因子。     

Functional effects of NAD(P)H oxidase p22(phox) C242T mutation in human leukocytes and association with thrombotic cerebral infarction

BACKGROUND: Previous study showed that polymorphism of the NAD(P)H oxidase p22(phox) gene is associated with atherosclerosis, although others could not confirm such association. We investigated the association between p22(phox) C242T polymorphism and thrombotic cerebral infarction and the role of this polymorphism on superoxide-production activity in human neutrophils and promyelocytic HL-60 cells as a model system. METHODS: PCR-RFLP analysis revealed that genotype and allele frequencies of C242T polymorphism in 120 patients with thrombotic cerebral infarction and 177 control subjects. The superoxide-production activity in neutrophils was determined by cytochrome c reduction assay. To clarify the role of p22(phox) C242T polymorphism on NAD(P)H oxidase activity, we used transgenic HL-60 cells transfected with expression plasmids carrying p22(phox) cDNAs with or without C242T polymorphism. RESULTS: Genotype and allele frequencies of C242T polymorphism in patients and control subjects were not significantly different. The superoxide-production activity in neutrophils with T allele was higher than in neutrophils without T allele. Moreover, expression analysis showed that superoxide-production activity in p22(phox) C242T-expressing HL-60 cells were significantly higher than in p22(phox)-expressing HL-60 cells. CONCLUSIONS: We conclude that C242T of p22(phox) gene is not involved in thrombotic cerebral infarction but more likely in increased NAD(P)H oxidase activity in phagocytes.     

The paradoxical association of common polymorphisms of the renin-angiotensin system genes with risk of myocardial infarction.

BACKGROUND: The insertion/deletion polymorphism of the angiotensin-converting enzyme (ACE) and the A1166C polymorphism of the angiotensin-II AT1 receptor (AT1R) have been extensively investigated as possible risk factors for myocardial infarction (MI). DESIGN AND METHODS: Genetic association, case-control study, specifically designed to investigate the association of the above-mentioned polymorphisms with risk of MI in a homogeneous, low coronary risk, Caucasian population. The study population consisted of 1603 consecutive patients with acute MI who were recruited from nine clinics, located in three cities, and 699 unrelated adults who were randomly selected from the city catalogues. RESULTS: In univariate analysis, the DD genotype was found to be more prevalent among controls (40.8 vs. 35.2%, P=0.011). In multivariate analysis adjusted for age, gender, smoking status, diabetes mellitus, hypercholesterolaemia, hypertension and family history of coronary artery disease, the presence of the DD genotype was independently and negatively associated with risk of AMI (RR=0.743, 95% CI=0.595-0.927, P=0.008). The CC genotype was not found to be significantly associated with risk of MI, either in univariate (6.2 vs. 6.4%, P=0.856), or in multivariate analysis adjusted for the same confounders (RR=0.743, 95% CI=0.473-1.167, P=0.197). CONCLUSIONS: Contrary to previous reports, in this study the DD genotype of the ACE gene, but not the CC genotype of the AT1R gene, was associated with a lower risk of MI. Our results emphasize the complexity of genotype-phenotype interactions in the pathogenesis of ischaemic heart disease and question the previously hypothesized role of the DD genotype on risk of acute myocardial infarction.     

ACE gene polymorphism in cardiovascular disease: meta-analyses of small and large studies in whites

The objective of this study was to assess the influence of the ACE gene insertion (I)/deletion (D) polymorphism on plasma ACE activity; blood pressure; and risk of myocardial infarction, ischemic heart disease, and ischemic cerebrovascular disease by comparing small and large studies. The meta-analyses are based on a literature search of MEDLINE up until April 1998 and assessment of bibliographies of published studies and reviews. Forty-six studies were selected, including a total of 32 715 white individuals. Plasma ACE activity was increased 40% and 71% for ID and DD versus II in small studies and 21% and 48% in large studies (small versus large: P<0.001 and P<0.001). Blood pressure was not influenced by genotype. Risk of myocardial infarction and ischemic heart disease was increased by 47% and 29%, respectively, for DD versus ID and II genotypes in small studies but not in large studies (small versus large: P<0.001 for risk of myocardial infarction and P=0.01 for risk of ischemic heart disease). Risk of ischemic cerebrovascular disease was not increased either in the small or in the largest study. In conclusion, the ACE gene polymorphism affects plasma ACE activity but not blood pressure and is not associated with increased risk of myocardial infarction, ischemic heart disease, or ischemic cerebrovascular disease in the largest studies.     

Insertion/Deletion Polymorphism of the Angiotensin I-Converting Enzyme Gene Is Associated With Coronary Artery Plaque Calcification As Assessed by Intravascular Ultrasound

Objectives. We evaluated the influence of the insertion/deletion (I/D) polymorphism of the angiotensin I-converting enzyme (ACE) gene on coronary plaque morphology and calcification in patients with angiographically documented coronary artery disease (CAD).Background. The ACE I/D polymorphism has been associated with an increased risk of myocardial infarction in patients with the DD genotype but not with the presence of native CAD.Methods. We studied 146 patients undergoing percutaneous transluminal coronary angioplasty for stable angina pectoris by means of preinterventional intravascular ultrasound (IVUS). Qualitative and quantitative criteria were used to classify the target lesions as poorly or highly echoreflective or as calcified. Genomic deoxyribonucleic acid was analyzed by polymerase chain reaction (PCR) to identify the I/D polymorphism, with a second insertion-specific PCR in DD genotypes to prevent mistyping.Results. The ACE genotype groups (DD 46, ID 68, II 32) were well matched for the basic characteristics. Patients with the DD genotype had significantly more calcified lesions (DD 80%, ID 57%, II 66%; unadjusted odds ratio [OR] 2.88, 95% confidence interval [CI] 1.30 to 6.92, p = 0.008) and more calcifications >180° of the vessel circumference (DD 22%, ID 10%, II 6%; OR 2.80, 95% CI 1.05 to 7.63, p = 0.03). The prevalence of myocardial infarction was not significantly associated with coronary calcification (OR 1.44, 95% CI 0.72 to 2.88, p = 0.31).Conclusions. Patients with CAD and the ACE DD genotype have a significantly higher incidence and greater extent of coronary lesion calcification, as determined by IVUS. This finding indicates that the ACE I/D gene polymorphism is related to the development or progression of atherosclerotic plaque calcification.     

血管紧张素转化酶基因插入/缺失多态性与冠心病发病的关系

目的 :探讨血管紧张素转化酶 (ACE)基因多态性与冠心病 (CHD)发病的关系。方法 :以人基因组DNA为模板 ,应用聚合酶链式反应 (PCR)检测 5 0例CHD组和 5 6例正常对照组ACE基因第 16内含子插入 /缺失 (I/D)多态性 ,并按性别分组计算各组基因型和等位基因频率。结果 :①在CHD组中 ,ACE基因DD基因型和D等位基因频率分别为 36 %和 6 0 % ,正常对照组分别为 16 %和 4 1% ,两者相比差异有统计学意义 (P <0 .0 1)。②男性CHD组DD基因型和D等位基因频率均显著高于对照组 (均P <0 .0 5 )。女性CHD组DD基因型频率显著高于对照组 (P <0 .0 1) ,D等位基因频率与对照组比较差异无统计学意义。结论 :CHD与ACE基因I/D多态性有显著相关性 ,不论男性和女性 ,ACE基因DD基因型均可能是CHD发生发展过程中重要的危险因素之一。     

血管紧张素转换酶基因多态性与冠脉病变严重程度的相关性研究

目的探讨血管紧张素转换酶(ACE)基因I/D多态性与冠心病及冠脉病变严重程度的关系.方法对122例冠心病患者进行冠状动脉造影,判定冠脉病变支数(狭窄程度≥75%)和危险记分.用聚合酶链式反应(PCR)技术检测病例组和80例健康人群ACE基因多态性.结果ACE基因型分布和等位基因频率在病例组和对照组间差异有显著性,病例组DD基因型(38.5%)和D等位基因频率(55%)显著高于对照组(13.7%,41%;P＜0.05).冠脉病变支数和危险记分在ACE基因型间差异无显著性(P＞0.05).结论ACE基因多态性中DD型和D等位基因是冠心病发病的独立危险因素,但与冠脉病变严重程度不相关.     

基因芯片技术分析老年冠心病患者的易感基因

目的 研究血管紧张素转换酶（ACE）、血管紧张素原（AGT）及内皮型一氧化氮合酶（eNOS）基因多态性与老年人冠心病（CHD）的关系.方法 选择老年CHD患者100例及对照者91例,应用基因芯片技术检测ACE、AGT和eNOS基因多态性,并比较其基因型及等位基因频率。结果 CHD组ACE DD基因型频率（28.0%）与对照组（15.4%）比较，差异有统计学意义（P＜0.05）,ACE基因多态性与老年CHD相关.AGT TT基因型频率（75.0%）与对照组（51.7%）比较，差异有统计学意义（P＜0.01）,AGT基因多态性与老年CHD相关.eNOS TT基因型频率（5.0%）与对照组（0.0%）比较,差异无统计学意义（P＞0.05）。同时携带ACE DD和AGT TT基因型或AGT TT和eNOS TT基因型者与老年CHD呈显著正相关（OR=2.9,P＜0.05,OR=1.1,P＜0.05）。结论 ACE和AGT基因多态性可能是中国老年人CHD的危险因素。     

Deletion polymorphism of the angiotensin converting enzyme gene is associated with an increase in left ventricular mass in men with type 2 diabetes mellitus.

Previous studies evaluating the angiotensin converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism have revealed that expression of the DD genotype is associated with an increase in myocardial infarction, cardiomyopathy, and left ventricular (LV) mass in nondiabetic patients. In the present study, a cross-sectional analysis was performed to evaluate the potential relationship between the ACE I/D genotypes and the LV mass index in 289 non-insulin-dependent diabetes mellitus (NIDDM) subjects without known coronary artery disease. Two dimensional directed M-mode echocardiograms along with selected patient characteristics were obtained from the study population. The distribution of the I/D polymorphism was as follows: 63 were II (22%), 137 were ID (47%), and 89 were DD (31%). Univariately, the DD genotype was associated with an increase in LV mass in men but not in women. When subjected to a multiple regression model that included age, systolic blood pressure, duration of diabetes, duration of hypertension, presence of the black race, and the presence of the DD genotype, the DD genotype was independently associated with an increase in the LV mass index with a parameter estimate of 10.5 g/m2 (95% CI = 3.9, 17.0; P < .002) in the male subjects. Thus, in this NIDDM study population, male patients with the DD genotype are independently associated with an increased LV mass.     

NADH/NADPH oxidase p22 phox gene polymorphism is associated with improved coronary endothelial vasodilator function.

AIMS: The NADH/NADPH oxidase system plays a central role in vascular superoxide anion production, which appears to cause coronary endothelial dysfunction. Recently, it has been suggested that the C242T polymorphism of the NADH/NADPH oxidase p22 phox gene can reduce susceptibility to coronary artery disease. We therefore tested whether this polymorphism is associated with an altered endothelium-dependent vasodilator capacity of human coronary arteries in vivo. METHODS AND RESULTS: The vasodilator function of epicardial arteries in 93 patients was assessed by endothelium-mediated, flow-dependent dilation and nitroglycerin, which is endothelium-independent. NADH/NADPH oxidase p22 phox polymorphism was determined by restriction fragment length polymorphism. Carriers of the CC genotype of the C242T p22 phox polymorphism (n = 44) revealed a significantly blunted endothelium-dependent dilator response (11 +/- 9.2% luminal area change vs 17 +/- 10%;P = 0.007), which was, by multivariate analysis, independent of other risk factors or atherosclerosis itself. There was only a trend towards decreased endothelium-independent dilation in patients bearing the p22 phox CC genotype (P = 0.07). CONCLUSIONS: The C242T polymorphism of the p22 phox gene is an important independent determinant of coronary endothelial vasodilator function. These results provide the first clinical evidence for the functional significance of a polymorphism of a gene related to superoxide anion production in the vascular wall.