Role of angiotensin converting enzyme, paraoxonase 1 55, 192 gene polymorphisms in syndrome X and coronary heart disease

Implications of ACE (I/D) Gene Variants to the Genetic Susceptibility of Coronary Artery Disease in Asian Indians

Angiotensin-1-converting enzyme (ACE) gene has established substantial attention in the recent years as a candidate gene for hypertension, cardiovascular diseases and type 2 diabetes. The aim of the present study was to investigate the association of ACE (I/D) polymorphism with coronary artery disease (CAD) in a north Indian population. A total of 662 subjects (330 CAD patients and 332 healthy controls) were examined for association of ACE gene (I/D) polymorphism and environmental risk factors. The mean age of the CAD patients and control subjects was 60.53 ± 8.6 years and 56.55 ± 7.7 years, respectively (p = 0.000). Anthropometric and demographic data showed BMI values significantly higher among CAD patients and control subjects (26.98 ± 4.9 vs 24.04 ± 4.7, p = 0.000). We observed pronounced central obesity in both CAD patients and controls, even at the lowest BMI values (<23 kg/m²). Dyslipidemia was highly prevalent in CAD patients compared to control subjects. Genotypic data showed significantly higher frequency of DD genotype in CAD patients than that of control subjects (40 vs 28.3 %). No significant difference was observed in the distribution of ID genotypes between CAD patients and control subjects. Logistic regression analysis of data demonstrate that DD genotype was associated with 1.8 fold increased risk of development of CAD in Asian Indians (OR 1.8; 95 % CI 1.22-2.66; p = 0.003). The frequency of D allele was significantly higher in CAD patients (p = 0.001). No significant difference was observed in the clinical and biochemical characteristics of CAD patients and controls when the data was stratified according to the genotypes of ACE gene. In conclusion, DD genotype of ACE gene may be associated with increased risk of CAD in Asian Indian population.

The ACE insertion/deletion polymorphism and its association with metabolic syndrome

The angiotensin-1-converting enzyme (ACE) gene has been suggested to be involved in the development of metabolic syndrome (MetS). However, results have been inconsistent. In this study, a meta-analysis was performed to investigate the association between ACE insertion/deletion (I/D) polymorphism and MetS. Published literature from PubMed, EMBASE, and ISI Web of Science databases was searched for eligible publications. All studies assessing the association between ACE I/D polymorphism and MetS were included. Pooled odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were calculated using a fixed- or random-effects model. Ten studies (1939 cases/2845 controls) for ACE I/D polymorphism were included in this meta-analysis. Most of the studies were performed in whites. The ACE I/D polymorphism was associated with an increased OR of MetS under a dominant model (DD + ID vs II: OR = 1.39; 95% CI, 1.22-1.60; P < .001). Using this model, similar results were found among studies using different ethnic populations, studies using different MetS definitions, and studies with more than 100 cases. This meta-analysis indicated that the D allele of the ACE gene, known to be related to higher levels of angiotensinogen, is associated with an increased OR of MetS. However, given the limited sample size, this association warrants further investigation.

Four genetic polymorphisms of paraoxonase gene and risk of coronary heart disease: a meta-analysis based on 88 case-control studies

OBJECTIVE

The human paraoxonase (PON) is calcium dependent HDL associated ester hydrolase which has attracted considerable attention as a candidate gene for coronary heart disease based on its enzyme function as a key factor in lipoprotein catabolism pathways. Many studies have examined the association between polymorphisms in the PON gene and risk of coronary heart disease (CHD), but the results have been inconsistent.

METHODS

We conducted a meta-analysis of 88 studies on 4 PON polymorphisms [Q192R, L55M, and T(-107)C in the PON1 and the S311C in the PON2] published before August 2010, including a total of 24,702 CHD cases and 38,232 controls. We also systematically explored potential sources of heterogeneity.

RESULT

In a combined analysis, the summary per-allele odds ratio for CHD of the 192R was 1.11 (95% CI: 1.05-1.17). However, when the analyses were restricted to 10 larger studies (n>500 cases), the summary per-allele odds ratio was 0.96 (95% CI: 0.90-1.02). Our analyses detected a possibility of publication bias with an overestimate of the true association by smaller studies. A meta-analysis of studies on the 55M, (-107)T, and 311C variant showed no significant overall association with CHD, yielding a per-allele odds ratio of 0.94 (95% CI: 0.88-1.00), 1.02 (95% CI: 0.91-1.15) and 1.02 (95% CI: 0.90-1.16) respectively.

CONCLUSIONS

This meta-analysis suggested an overall weak association between the R192 polymorphism and CHD risk.