Meta-analysis of the association of 4 angiotensinogen polymorphisms with essential hypertension: a role beyond M235T?

Angiotensinogen (AGT) gene polymorphisms have been linked to increased risk of hypertension, but the data remain controversial. In this study we review the most commonly investigated polymorphisms at the AGT locus (other than M235T) and provide summary estimates regarding their association with essential hypertension, while addressing heterogeneity, as well as publication biases. Data on 26 818 subjects from 46 studies for the 4 most-studied AGT variants (T174M in exon 2 and 3 promoter variants: A-6G, A-20C, and G-217A) were meta-analyzed. Statistically significant associations with hypertension were identified for the T174M (odds ratio [OR]: 1.19; 95% CI: 1.07 to 1.33; P=0.002) and G-217A (OR: 1.37; 95% CI: 1.17 to 1.59; P=0.00006) polymorphisms. A dual but consistent effect was observed for the -20C allele, which was associated with a decreased risk of hypertension in populations of mixed and European ancestries (OR: 0.64; 95% CI: 0.44 to 0.92; P=0.02 and OR: 0.77; 95% CI: 0.65 to 0.91; P=0.003, respectively), but with a 24% increase in the odds of hypertension in Asian subjects (OR: 1.24; 95% CI: 1.04 to 1.48; P=0.02). No association of the A-6G variant with hypertension was detected. Current studies support the notion that single variants at the AGT might modulate the risk of hypertension but indicate caution in interpreting these results because of the putative presence of publication bias and gene-environment interactions.     

肾素-血管紧张素系统基因多态性与原发性高血压左心室肥厚关系的探讨

目的　探讨肾素 血管紧张素系统 (RAS)基因多态性与原发性高血压左心室肥厚 (EH LVH)的相关性以及在EH LVH产生中的多基因协同作用。方法　对 10 9例原发性高血压病 (EH)患者 ,采用聚合酶链反应 (PCR)以及聚合酶链反应 限制性片段长度多态性方法检测血液白细胞染色体DNA中血管紧张素转换酶 [ACE(I D) ]、血管紧张素原 [AGT(M2 35T) ]和血管紧张素Ⅱ 1型受体 [AT1 R(A116 6C) ]基因多态性 ;利用超声心动图检测左心室质量 (LVM)并计算左心室质量指数 (LVMI)。结果　ACE(I D)基因多态性D等位基因频率在EH LVH组中明显增高 (χ2 =4 .6 9,P=0 .0 30 ) ,男性EH患者中 ,ACE(I D)基因型构成比与LVH有关联 (χ2 =9.5 5 ,P =0 .0 0 8)。协同存在AGT TT型时 ,ACE(I D)基因多态性与EH LVH有关 (χ2 =6 .2 2 ,P =0 .0 4 4 ) ,且D等位基因在EH LVH明显增高 (χ2 =6 .91,P =0 .0 0 9) ,该类EH患者发生LVH的相对危险度增高 (OR :2 .5 0 ,95 %CI:1.2 5～ 5 .0 0 )。结论　ACE(I D)基因多态性D等位基因可能是LVH的独立危险因子。ACE基因多态性与AGT基因多态性之间的协同效应表明 ,同时携带AGT TT型时 ,具有ACE(I D)基因多态性D等位基因的EH患者更易发生LVH。     

血管紧张素原基因和血管紧张素转换酶基因多态性与高血压

目的　研究中国人群中血管紧张素原 (AGT)基因单核苷酸多态性 (SNP)及血管紧张素转换酶 (ACE)基因插入 /缺失多态与高血压病的关系。方法　在 3 4 5例高血压病患者与 2 0 6名血压正常人中采用PCR RFLP法检测AGT基因A 2 0C ,A 6G和M 2 3 5T的多态性 ,用PCR法检测ACE基因 16内含子Alu片段插入 /缺失多态 ,同时用EM算法进行两位点连锁不平衡分析。结果　在M 2 3 5T和A 2 0C ,M 2 3 5T和A 6G ,A 2 0C和A 6G位点观察到了连锁不平衡 (P <10 - 4)。病例 对照检验显示T2 3 5等位基因频率在高血压组中高于对照组 ,且高血压病患者中ACE (DD +ID) +AGT TT2 3 5基因型频率高于对照组。结论　受检人群中AGT基因各多态频率处于两两连锁不平衡 ,但AGT基因即T2 3 5位点以隐性作用方式与高血压关联 ,T2 3 5等位基因与ACE D等位基因在高血压病发生中具协同作用     

Genetic variation in the renin-angiotensin system modifies the beneficial effects of ACE inhibitors on the risk of diabetes mellitus among hypertensives

The aim of this study was to assess whether the association between angiotensin-converting enzyme (ACE) inhibitor use and the incidence of treated diabetes mellitus is modified by genetic polymorphisms in the renin-angiotensin system (RAS).In a nested case-control study, treated hypertensive patients were genotyped for ACE (insertion (I)/deletion (D)), angiotensinogen (AGT; M235T) and angiotensin II type 1 receptor (AGTR1; A1166C). Cases of newly treated diabetes were identified based on pharmacy records and controls were not yet drug treated for diabetes (case:control ratio 1:10). Self-administered questionnaires and physical examinations were used to assess risk factors for diabetes mellitus. Logistic regression was used to calculate the relative risk of diabetes associated with ACE inhibitor use relative to other antihypertensive treatment, stratified by the RAS genotypes. Among 205 cases and 2050 controls, homozygous 1166A carriers of the AGTR1 gene had a significantly decreased incidence of diabetes associated with current use of ACE inhibitors (odds ratio, OR: 0.47; 95% CI: 0.26-0.84), whereas this incidence was increased among 1166C allele carriers (OR: 1.32; 95% CI: 0.81-2.14). The interaction OR was 3.21 (95% CI: 1.53-6.75). ACE I allele carriers had a significantly reduced incidence of diabetes associated with ACE inhibitors use (OR: 0.63; 95% CI: 0.41-0.98), whereas DD homozygotes had no reduced risk (OR: 0.95; 95% CI: 0.46-1.96). The risk of diabetes associated with ACE inhibitor use was not significantly modified by the AGT-M235T polymorphism. Treatment with ACE inhibitors in hypertensive subjects significantly reduces the occurrence of diabetes in homozygous 1166A carriers of the AGTR1 gene and carriers of the ACE I allele, but not in 1166C allele carriers of the AGTR1 gene and in homozygous ACE D allele carriers.     

Genetic polymorphisms of the renin-angiotensin system and atheromatous renal artery stenosis

Genes that influence the renin-angiotensin system have been investigated in recent years as potential etiologic candidates of cardiovascular and renal diseases. In atheromatous renal artery stenosis (RAS), a condition characterized by persistent activation of the renin-angiotensin system, the study of these genes may be of particular relevance. We evaluated angiotensin-converting enzyme (ACE) insertion/deletion, angiotensinogen (AGT) M235T, and angiotensin II receptor (ATR) A1166C polymorphisms in relation to the occurrence of RAS. We studied 58 patients with angiographically documented RAS; 102 normotensive subjects with normal coronary arteries and no history or clinical or instrumental evidence of atherosclerosis in other vascular districts were considered the control group. Patients had a significantly higher D allele frequency (0.70 versus 0.55; chi(2) 6.88, P=0.01; odds ratio [OR] 1. 9, 95% CI 1.17 to 3.07) than did the control population; 48.3% of patients were homozygous for DD (chi(2) 6.62, P<0.05; OR 2.04, 95% CI 1.05 to 3.95); and only 8.6% carried the II genotype (OR 0.34, 95% CI 0.19 to 1.47). No significant association was found for AGT M235T and ATR A1166C. Our results suggest a predisposing role for ACE genetic polymorphism in the development and progression of atheromatous RAS.     

Association of two angiotensinogen gene polymorphisms,M235T and G(-6)A,with chronic heart failure

The aim of the study was to focus on the relationship between the angiotensinogen (AGT) gene polymorphisms, M235T and promoter G(-6)A, and chronic heart failure in the Czech population. A total of 158 patients with chronic heart failure (functional class NYHA II-IV, ejection fraction <40%, cardiothoracic index >50%) were compared with a control group of 200 subjects of similar age and sex distribution, without any personal history of cardiovascular diseases. The AGT gene polymorphisms were detected by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) methods. No significant differences in distributions of AGT genotypes between patients with chronic heart failure (CHF) and controls were found. The differences in distributions of alleles in AGT M235T (P(a)=0.02) and genotypes in AGT G(-6)A (P(g)=0.017) were found within women groups. Within CHF patients the distribution of AGT G(-6)A genotypes was not consistent with Hardy-Weinberg equilibrium (P=0.0001). We found significant relative risk of CHF in the GGMT genotype, OR=2.63 with 95% CI 1.39-4.95, P(corr)=0.01 (in the male group OR=1.83, 95% CI 0.92-3.66, P(corr)=0.3; in the female group OR=15.5, 95% CI 1.86-129.42, P(corr)=0.008). We provide evidence of increased risk in subjects with the GGMT variant of associated genotype of AGT gene for CHF, especially of fifteen-fold risk of this variant in women.     

Polymorphisms in the promoter region of the angiotensinogen gene are associated with liver cirrhosis in patients with chronic hepatitis B

BACKGROUND AND AIMS: It is known that the renin-angiotensin system (RAS) regulates fibrosis. Polymorphisms in the genes of the RAS may contribute to the outcome of liver cirrhosis. Angiotensinogen (AGT), mainly produced in the liver, is the substrate of renin. The aim of this study was to determine whether polymorphisms in the promoter region of the AGT gene are associated with liver cirrhosis in patients with chronic hepatitis B. METHODS: Restriction fragment length polymorphism PCR was used to study polymorphisms in the promoter region of the AGT gene in patients with liver cirrhosis and in a control population. Four polymorphisms were assayed: G-217A, G-152A, A-20C and A-6G. RESULTS: A statistically significant relationship was seen between polymorphisms of the AGT core promoter region and liver cirrhosis in patients with chronic hepatitis B (A-20C, P = 0.007; A-6G, P = 0.042). However, the distributions of the AGT-217 and AGT-152 genotypes were not significantly different from the control population (P = 0.615 and P = 0.170, respectively). CONCLUSIONS: Polymorphisms of the core promoter region of the AGT gene (AGT-20 and AGT-6) were associated with liver cirrhosis in patients with chronic hepatitis B.     

Interaction between gene polymorphisms of renin-angiotensin system and metabolic risk factors in premature myocardial infarction

The renin-angiotensin system is involved in the pathogenesis of coronary artery disease (CAD) and myocardial infarction (MI). The authors investigated the association of genetic variability in the renin-angiotensin system (RAS) with premature MI and interactive effects between gene polymorphisms and metabolic risk factors on MI risk. Their study compared 142 patients with MI younger than 55 years with 142 healthy subjects. Polymorphisms of angiotensin-I converting enzyme (ACE) gene (insertion/deletion), angiotensinogen gene (M235T), and angiotensin-II type-1 receptor (AGT1R) gene (A1166C) were tested. The ACE-DD (deletion/deletion) genotype conferred a twofold independent risk for MI (confidence interval [CI] = 1.1-3.7; p = 0.01) after adjustment for cardiovascular risk factors, whereas angiotensinogen-TT genotype and AGT1R-AA genotype were not independent risk factors for MI. An interactive effect on MI risk was found between ACE-DD and AGT1R-AA genotypes (odds ratio [OR]=2, 95% CI= 1-3.9), between ACE-DD and angiotensinogen-TT genotypes (OR = 2.7, 95% CI = 1-7.3), as well as among ACE-DD, angiotensinogen-TT, and AGT1R-AA genotypes (OR=4.8, 95% CI = 1-22.8). Similarly, metabolic risk factors interacted with angiotensinogen-TT genotype (OR= 2, 95% CI = 1.1-3.9) on MI risk. The ACE-DD genotype is an independent risk factor for MI in patients younger than 55 years. Additionally, the authors provide evidence of an interactive effect on MI risk between risk genotypes of RAS, as well as between the angiotensinogen-TT genotype and metabolic risk factors.     

Renin-angiotensin system gene polymorphisms and coronary artery disease in a large angiographic cohort: detection of high order gene-gene interaction

There have been many reports regarding the association between renin-angiotensin system (RAS) gene polymorphisms and coronary artery disease (CAD) or acute myocardial infarction (AMI), but the results are inconsistent. In the present study, we used several new approaches with multilocus data to reappraise this issue in a large and relatively homogeneous Taiwanese population. A total of 1254 consecutive patients who underwent cardiac catheterization (735 with documented coronary artery disease and 519 without) between 1996 and 2003 were recruited. Angiotensin-converting enzyme gene insertion/deletion (I/D) polymorphism; T174M, M235T, G-6A, A-20C, G-152A and G-217A polymorphisms of the angiotensinogen gene; and A1166C polymorphism of the angiotensin II type I receptor gene were genotyped. In single-locus analyses, no locus was associated with CAD, history of AMI and three-vessel CAD, either with or without adjustment for conventional CAD risk factors. For multilocus analyses, we recreated a balanced population, with the controls individually matched to the cases regarding the conventional CAD risk factors. We found that the angiotensinogen gene haplotype profile was significantly different between the cases and controls (chi2=31.6, P=0.030) in haplotype analyses. Furthermore, significant three-locus (G-217A, M235T and I/D) gene-gene interactions were detected by multifactor-dimensionality reduction method (highest cross-validation consistency 10.0, lowest prediction error 40.56%, P=0.017) and many even higher order gene-gene interactions by multilocus genotype disequilibrium tests (16 genotype disequilibria exclusively found in the controls, all of which included at least two genes among AGT, ACE and AT1R genes). Our study is the first to demonstrate epistatic, high-order, gene-gene interactions between RAS gene polymorphisms and CAD. These results are compatible with the concept of multilocus and multi-gene effects in complex diseases that would be missed with conventional approaches.     

简化的血管紧张素原基因单倍型分析与原发性高血压的关系

目的探讨血管紧张素原(AGT)基因连锁不平衡状态、单倍型及与原发性高血压的关系。方法选取497例病例对照样本,采用。PCR-RFIP法检测AGT基因7个位点多态性,同时用最大期望值(EM)算法进行两位点连锁不平衡和单倍型结构估计。结果A-6G,C 31T,T235M三位点两两存在完全连锁不平衡(D’=1)。用5种多态(A-217G,G-152A,A-20C,T174M和T235M)和7种多态(A-217G,G-152A,A-20C,A-6G,C 31T,T174M)估计单倍型结果相同。病例对照研究发现单倍型H2在病例组中频率高于对照组;单个位点分析未见与高血压关联。结论AGT基因研究中A-6G,C 31T,T235M三种多态可简化为其中一种;H2单倍型可能与控制血压的保护性因素连锁不平衡。     

Interaction between GNB3 C825T and ACE I/D polymorphisms in essential hypertension in Koreans

Essential hypertension (EH) is considered a typical polygenic disease, so the evaluation of gene-gene interactions rather than the determination of single gene effects is crucial to understanding any genetic influences. The G-protein beta3-subunit (GNB3) 825T allele, associated with enhanced G-protein signalling, is a strong candidate for interactions with polymorphisms, such as insertion/deletion (I/D) polymorphism of angiotensin I-converting enzyme (ACE) gene. We investigated whether there is an association between GNB3 C825T and ACE I/D polymorphisms for the development of EH. We carried out a case-control study of 688 hypertensive and 924 normotensive subjects recruited from South Korea. The GNB3 C825T and ACE I/D genotypes were determined by polymerase chain reaction (PCR) and PCR-restriction fragment length polymorphism methods, respectively. The distributions of alleles and genotypes for the GNB3 C825T and ACE I/D polymorphisms were not found to be significantly associated with hypertensive status in either males or females. Logistic regression analysis indicated that the GNB3 825T allele carriers were positively associated with EH in males (odds ratio (OR) for TT/CT, 1.459; 95% confidence interval (CI), 1.048-2.033, P=0.0255). In analysis of gene-gene interaction, we found that there was a significant interaction between the GNB3 825T and ACE D alleles (P<0.05). OR for EH was significantly higher in 825T allele carriers with ACE D allele (OR, 1.490; 95% CI, 1.117-1.987, P=0.0067). A significant interaction between the GNB3 825T and the ACE D alleles may contribute to the predisposing effect for the development of EH in Koreans.     

Association between angiotensinogen gene M235T polymorphism and mitral valve prolapse syndrome in Taiwan Chinese

BACKGROUND AND AIM OF THE STUDY: It has been reported that patients with mitral valve prolapse syndrome (MVPS) also have a disorder in autonomic or neuroendocrine function which can cause many related symptoms. Although a potential role of the reninangiotensin system in the pathogenesis of MVPS has been addressed, the role of the angiotensinogen (AGT) genetic variant in MVPS has not been studied. Thus, a case-controlled study was performed to investigate the possible relationship between AGT gene polymorphisms and MVPS. METHODS: A total of 100 patients with MVP diagnosed by echocardiography and 100 age- and sex-matched normal control subjects was studied. AGT gene M235T and T174M polymorphisms were identified by polymerase chain reaction-based restriction analysis. RESULTS: There was a significant difference in the distribution of AGT gene M235T genotypes (p <0.001) and allelic frequencies (p <0.001) between MVPS cases and controls. An Odds Ratio (OR) for risk of MVPS associated with M235T TT genotype was 8.55 (95% CI 4.51-16.18). An OR for risk of MVPS associated with the T allele at the M235T locus of the AGT gene was 3.27 (95% CI 2.05-5.22). The T174M polymorphism of AGT gene showed no association with MVPS (p = 0.94). CONCLUSION: These findings suggest that the M235T polymorphism of the AGT gene is associated with MVPS in the Chinese population of Taiwan. The association of the TT genotype with MVPS is more noteworthy than an overall increase in the frequency of the T allele at the M235T locus.     

血管紧张素原基因启动子区域单核苷酸多态与高血压并发冠心病的关系

目的　研究在中国南方汉人群中 ,血管紧张素原基因 (angiotensinogen ,AGT)启动子区域 2 17位和 2 0位上的二种单核苷酸多态与高血压病 (EH)并发冠心病的关系。方法　运用多重SNaPshot反应 ,对 2 0 5例EH并发冠心病患者、185例EH患者和 185名健康对照者进行G 2 17A和A 2 0C多态基因分型。结果　G 2 17A多态的基因型分布在EH并发冠心病组 (AA =8、AG =71、GG =12 6 )和对照组 (AA =8、AG =37、GG =14 0 )之间有显著性差异 (P =0 0 0 5 ) ;A、G等位基因频率与对照组相比亦有显著性差异 (A 2 1 2 2 %、G 78 78%比A 14 32 %、G 85 6 8% ,P =0 0 12 ) ;A 2 0C多态的基因型分布 (CC、AC、AA)及C、A等位基因频率在二组间的差异无显著性 (分别为CC =5、AC =4 9、AA =15 1比CC =2、AC =6 1、AA =12 2 ,P =0 0 97;C 14 39%、A 85 6 1%比C 17 5 7%、A 82 4 3% ,P=0 2 2 6 )。在男性EH并发冠心病组中 ,G 2 17A和A 2 0C多态的基因型分布及其等位基因频率与对照组相比均有显著性差异 (G 2 17A :AA =7、AG =5 3、GG =86比AA =6、AG =2 8、GG =97,P =0 0 2 2 ;A 2 2 95 %、G 77 0 5 %比A 15 2 7%、G 84 73% ,P =0 0 2 2。A 2 0C :CC =3、CA =2 7、AA =116比CC =2、CA =4 3、AA =86 ,P =0 0 2 3;C 11 30 %     

Synergistic effects of gene polymorphisms of the renin–angiotensin–aldosterone system on essential hypertension in Kazakhs in Xinjiang

Objective: To assess the synergistic effects of gene polymorphisms of the renin–angiotensin–aldosterone system (RAAS) on essential hypertension (EH) in Kazakhs in Xinjiang. Methods: A cross-sectional case-control association study was conducted in 52 1 hypertensive and 623 normotensive subjects of Kazakh ethnicity on eight common single nucleotide polymorphisms (SNPs) interspersed over five genes of the RAAS. SNPs were genotyped by polymerase chain reaction-restriction fragment length polymorphism. Interactions among the SNPs were analyzed by the multifactor dimensionality reduction method (MDR). Results: In single-locus analysis, subjects with AGT -6G, ACE D, and CYP11B2 -344C had increased susceptibility to EH (OR: 1.249; 1.425; 1.201). When subgrouped by sex, males with the t allele of REN Taq I had decreased risk for EH (OR: 0.529), and those with AGT -6G and CYP11B2 -344 C had increased risk for EH (OR: 1.498; 1.449). In females, carrying ACE D increased the risk for EH. (OR: 1.327). In six AGT haplotypes, H1 was protective, while H3 increased susceptibility to EH (OR: 0.683; 2.025). Interaction analysis by MDR showed that there was a strong synergistic effect between ACE I/D and CY11B2 (T-344C) and a moderate interaction between both ACE I/D and CY11B2 T-344C and AGT A-6G. Conclusions: There was a strong synergistic effect between ACE I/D and CY11B2 T-344C and a moderate effect between both ACE I/D and CY11B2 T-344C and AGT A-6G. AGT -6G, ACE D, and CY11B2 -344C increased susceptibility to EH. REN Taq I, AGT -6G, CY11B2 -344 C and ACE D were associated with male and female EH, respectively. H1 and H3 of AGT were protective and risk haplotypes, respectively.     

血管紧张素原基因T174M和血管紧张素转换酶基因I/D多态性与急性心肌梗死的相关性

目的探讨中国汉族人群血管紧张素转换酶和血管紧张素原基因型的分布及其与急性心肌梗死的关系。方法应用聚合酶链反应技术,对112例急性心肌梗死患者、128例非冠心病患者血管紧张素转换酶I/D多态性及血管紧张素原T174M多态性进行检测。结果血管紧张素转换酶基因型分布及等位基因频率在病例组及对照组间差异有显著性(P<0.01)。病例组和对照组血管紧张素原基因型及等位基因频率总体分布差异亦有显著性(P<0.05)。联合基因分析显示,急性心肌梗死组血管紧张素转换酶DD基因型 血管紧张素原174MM基因型频率显著高于对照组(P<0.01),具有该联合基因型者发生冠心病的风险比数比(OR=8.467)明显高于单独具有血管紧张素转换酶DD基因型(OR=2.558)或血管紧张素原174MM基因型(OR=6.176)者。结论血管紧张素原T174M基因多态性中M等位基因和血管紧张素转换酶I/D基因多态性基因中的D等位基因是中国汉族人群冠心病发病的危险因素之一。同时具有血管紧张素转换酶DD型及血管紧张素原174MM型发生冠心病的相对风险显著高于单基因血管紧张素转换酶DD型及单基因血管紧张素原174MM型。     

Polymorphism in the angiotensin converting enzyme but not in the angiotensinogen gene is associated with hypertension and type 2 diabetes: the Skaraborg Hypertension and diabetes project

OBJECTIVE: To study the association between polymorphisms in the angiotensin converting enzyme (ACE) gene and angiotensinogen (AGT) gene and hypertension and/or type 2 diabetes in a community population. PATIENTS AND METHODS: The insertion (I)/deletion (D) polymorphism of the ACE gene and the M235T polymorphism of the AGT gene were genotyped in 773 nondiabetic individuals with hypertension, 193 normotensive patients with type 2 diabetes, 243 patients with type 2 diabetes and hypertension, and in 820 normotensive control individuals identified in a community-based study. RESULTS: The DD genotype was associated with hypertension in individuals less than 70 years [odds ratio (OR) = 1.54, confidence interval (CI) = 1.09-2.18] and remained so when patients with type 2 diabetes were excluded from the analysis (OR = 1.45, CI = 1.01-2.09). The strongest association was with the combination of type 2 diabetes and hypertension (OR = 2.19, CI = 1.09-4.38). There was no association with type 2 diabetes without hypertension. No association was observed between the M235T variant or the 3'-microsatellite polymorphism of the AGT gene and hypertension. CONCLUSION: The D-allele of the ACE gene ID polymorphism increases susceptibility to hypertension, particularly when associated with type 2 diabetes. No association was observed between the M235T variant or 3'-microsatellite polymorphism of the AGT gene and hypertension.     

Gene polymorphisms of the renin-angiotensin system and early development of hypertension

BACKGROUND: A case-control association study was conducted to investigate a possible involvement of polymorphisms of three renin-angiotensin system genes: ACE (I/D and T-3892C), AGT (M235T and T174M), and AT1R (A1166C) in the early development of hypertension. METHODS: One hundred nineteen hypertensive and 125 normotensive participants aged 18 to 40 years were selected from a broader sample representative of the general population of Croatia. The selection criteria for hypertensive cases were systolic blood pressure (BP) higher than 140 mm Hg or diastolic BP higher than 90 mm Hg and a history of hypertension according to patient interview. RESULTS: Among the polymorphisms investigated, only those located on the ACE gene were associated with hypertension. For ACE I/D, the odds ratio for hypertension of DD versus II homozygote individuals was 2.50 (95% confidence interval [CI] 1.19-5.25) and for ACE T-3892C, the odds ratio of CC versus TT individuals was 2.32 (95% CI 1.05-5.10). Both polymorphisms of the ACE gene were in tight linkage disequilibrium. Of the investigated risk factors for hypertension, only body mass index (BMI) showed an influence on the early development of hypertension, acting independently of the ACE polymorphism. Their additive effect gives rise to 86% of hypertensives in subjects having both the DD genotype and BMI >or=30 kg/m(2). CONCLUSIONS: The present study provides evidence of the association of the ACE gene polymorphisms and premature hypertension. In addition, BMI proved to be another important predictor of the disorder acting independently of the ACE gene.     

Genetic polymorphisms of angiotensinogen and essential hypertension in a Tibetan population.

The human angiotensinogen gene (AGT) is a promising candidate for an essential hypertension-susceptibility gene. We aimed to explore the single-locus, haplotype and epistasis patterns of three polymorphisms of AGT (A-20C, A-6G and M235T) and their relation to the risk of essential hypertension in a Tibetan population. The three polymorphisms were genotyped in 333 essential hypertension patients and 235 healthy controls on the basis of a door-to-door cross-sectional study. Genotyping was performed using polymerase chain reaction (PCR)-restriction fragment length polymerase (RFLP) and direct sequencing techniques. The data were analyzed using the EH/EH+ program and the multifactor dimensionality reduction (MDR) method. Our single-locus analysis revealed that except for a marginal, significant association of A-20C allele distribution, no significant association between genotype and allele distributions of the A-20C, A-6G, or M235T polymorphism of AGT and essential hypertension was found. In haplotype analysis, we found that the H(1) haplotype may be the risk-conferring factor for hypertension, even after the Bonferroni correction. In epistasis analysis, we selected the final best model, which included the A-20C and A-6G polymorphisms with a strong synergistic effect. This model had a maximum testing accuracy of 0.564 and a maximum cross validation consistency of 10 out of 10 (p=0.001). The present study thus provides evidence of a strong synergistic effect of the A-20C and A-6G polymorphisms of AGT, which were not found to be associated with essential hypertension in the single-locus analysis. Moreover, we have proposed a promising data-mining analytical method using the open-source MDR software package for detecting and characterizing gene-gene interactions.     

Association of angiotensinogen M235T and A(-6)G gene polymorphisms with coronary heart disease with independence of essential hypertension: the PROCAGENE study. Prospective Cardiac Gene

OBJECTIVES: We examined the relationship between the angiotensinogen (AGT) gene M235T polymorphism, the variant promoter of the AGT gene A(-6)G and the angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism and coronary heart disease (CHD) in native Gran Canaria Island habitants, who have the highest rates of CHD in Spain. BACKGROUND: Some studies subject that the ACE (I/D) polymorphism could be associated with CHD, while AGT (M235T) has been related to essential hypertension. METHODS: We studied 304 subjects with angiographic evidence of coronary artery disease and a clinical diagnosis of myocardial infarction or unstable angina and 315 age- and gender-matched controls. Blood was drawn and DNA extracted. Angiotensin-converting enzyme (I/D) gene polymorphism was analyzed by polymerase chain reaction (PCR) and AGT gene polymorphisms by restriction fragment length polymorphism-PCR and mutagenically-separated PCR. RESULTS: The ACE (I/D) polymorphism showed no association with CHD, whereas the frequency distribution of AGT (M235T) genotypes among patients and controls (235T: 29.1% and 19.0%; M235T: 48.5% and 50.2%; M235: 22.4% and 30.8%, respectively) was statistically different (p = 0.005) and not related to the presence of essential hypertension. Similar results were observed with the AGT A(-6)G polymorphism. In multiple logistic regression analysis, CHD odds ratio associated with 235T and M235 homozygotes were 1.7 (1.1 to 2.6) and 0.54 (0.36 to 0.82), respectively. CONCLUSIONS: This study shows that genetic variation of the AGT (M235T), but not the ACE (I/D), genotypes contributes to the presence of CHD independently of blood pressure profile in a subset of the Spanish population with a high prevalence of cardiovascular disease.