Association of aldosterone synthase (CYP11B2) gene -344T/C polymorphism with the risk of primary chronic glomerulonephritis in the Polish population

The Influence of ACE Insertion/Deletion Gene Polymorphism on the Risk of IgA Nephropathy: A Debatable Topic

Background

The connection between angiotensin-converting enzyme insertion/deletion (ACE I/D) gene polymorphisms and IgA nephropathy (IgAN) was conflicting. This pooled analysis was performed to explore this issue.

Methods

All eligible investigations were identified from various electronic databases, and the pooled analysis was evaluated using Stata software.

Results

27 studies with 2538 IgAN cases and 3592 controls were included. In overall subjects, ACE D allele, DD, and II genotype were associated with IgAN susceptibility (D vs. I: OR = 1.21, 95% CI: 1.10–1.32, P < 0.001; DD vs. ID + II: OR = 1.38, 95% CI: 1.20–1.60, P < 0.001; and II vs. DD + ID: OR = 0.83, 95% CI: 0.73–0.95, P=0.007). In Asian and Chinese patients, ACE I/D gene polymorphism was also correlated with IgAN vulnerability. Moreover, ACE D allele, DD, and II genotype were correlated with the progression of IgAN (D vs. I: OR = 1.37, 95% CI: 1.09–1.73, P=0.008; DD vs. ID + II: OR = 1.57, 95% CI: 1.06–2.31, P=0.024; and II vs. DD + ID: OR = 0.69, 95% CI: 0.49–0.99, P=0.045). Conversely, in Caucasian subjects, there was no link between ACE I/D gene polymorphism and the risk of IgAN.

Conclusion

ACE I/D gene polymorphism was correlated with the vulnerability and progression of IgAN in Asian and Chinese patients, and ACE D allele and DD homozygote genotype could be adverse factors for IgAN, while the II homozygote genotype could be an advantage factor. But, no significant association was found between ACE I/D gene polymorphism and IgAN in Caucasians.

Lack of association between CYP11B2 -344T/C polymorphism and transient ischemic attack in a Chinese population

OBJECTIVE

This study investigated whether the CYP11B2 -344T/C polymorphism is correlated with transient ischemic attack (TIA) susceptibility.

METHODS

We recruited 100 TIA patients and 100 control subjects and analyzed the CYP11B2 -344T/C polymorphism using restriction fragment length polymorphism (PCR-RFLP).

RESULTS

The frequency in TIA patients and controls was 42% compared with 48% for TT genotypes, 51% compared with 45% for TC genotypes, and 7% compared with 7% for CC genotype, respectively. Allele frequencies in TIA patients and controls were 67.5% compared with 70.5% for T-allele and 32.5% compared with 29.5% for C-allele, respectively. No association between the CYP11B2 -344T/C polymorphism and TIA was observed in all comparisons.

CONCLUSION

Our data suggest that there was no association between the CYP11B2 -344T/C polymorphism and TIA in a Chinese population.

Angiotensin II receptor type 1 A1166C modifies the association between angiotensinogen M235T and chronic kidney disease

Single nucleotide polymorphisms (SNPs) in renin-angiotensin system (RAS) genes are associated with RAS imbalance and chronic kidney disease (CKD). We performed a case-control study and meta-analysis to investigate the association between angiotensinogen (AGT) M235T polymorphism and CKD. A total of 634 patients with end-stage renal disease and 739 healthy controls were studied. We also searched PubMed and the Cochrane Library to identify prospective observational studies published before December 2015. We found that the TT and MT genotypes were associated with a higher risk of CKD than the MM genotype (odds ratio [OR]: 3.56; 95% confidence interval [CI]: 1.14-11.16 and OR: 2.93; 95% CI: 0.91-9.46, respectively). Thirty-eight study populations were included in the meta-analysis. The T allele was associated with a higher risk of CKD than the M allele in all populations (OR: 1.19; 95% CI: 1.08-1.32). The OR was 1.33 in Asians (95% CI: 1.06-1.67) and 1.10 in Caucasians (95% CI: 1.02-1.18). Evaluation of gene-gene and gene-environment interactions using epistasis analysis revealed an interaction between AGT M235T and angiotensin II receptor type 1 A1166C in CKD (OR: 0.767; 95% CI: 0.609-0.965). Genetic testing for CKD in high-risk individuals may be an effective strategy for CKD prevention.

Epistasis Test in Meta-Analysis: A Multi-Parameter Markov Chain Monte Carlo Model for Consistency of Evidence

Conventional genome-wide association studies (GWAS) have been proven to be a successful strategy for identifying genetic variants associated with complex human traits. However, there is still a large heritability gap between GWAS and transitional family studies. The "missing heritability" has been suggested to be due to lack of studies focused on epistasis, also called gene-gene interactions, because individual trials have often had insufficient sample size. Meta-analysis is a common method for increasing statistical power. However, sufficient detailed information is difficult to obtain. A previous study employed a meta-regression-based method to detect epistasis, but it faced the challenge of inconsistent estimates. Here, we describe a Markov chain Monte Carlo-based method, called "Epistasis Test in Meta-Analysis" (ETMA), which uses genotype summary data to obtain consistent estimates of epistasis effects in meta-analysis. We defined a series of conditions to generate simulation data and tested the power and type I error rates in ETMA, individual data analysis and conventional meta-regression-based method. ETMA not only successfully facilitated consistency of evidence but also yielded acceptable type I error and higher power than conventional meta-regression. We applied ETMA to three real meta-analysis data sets. We found significant gene-gene interactions in the renin-angiotensin system and the polycyclic aromatic hydrocarbon metabolism pathway, with strong supporting evidence. In addition, glutathione S-transferase (GST) mu 1 and theta 1 were confirmed to exert independent effects on cancer. We concluded that the application of ETMA to real meta-analysis data was successful. Finally, we developed an R package, etma, for the detection of epistasis in meta-analysis [etma is available via the Comprehensive R Archive Network (CRAN) at https://cran.r-project.org/web/packages/etma/index.html].

Gene-gene interactions in renin-angiotensin-aldosterone system contributes to end-stage renal disease susceptibility in a Han Chinese population

Objective. In this study, we investigated whether RAAS gene single nucleotide polymorphisms (SNPs) and their interactions were associated with end-stage renal stage (ESRD). Methodology and Results. This was a case-control study for 647 ESRD cases and 644 controls. AGT (M235T (rs699) and T174M (rs4762)), AGTR1 (A1166C (rs5186) and C573T (rs5182)), ACE (I/D (rs1799752) and G2350A (rs4343)), and CYP11B2 C-344T (rs1799998) were genotyped and compared between cases and controls to identify SNPs associated with ESRD susceptibility. Multifactor dimensionality reduction (MDR) was used to identify gene-gene interactions. Several RAAS genes were associated with ESRD: AGT M235T, ACE I/D, ACE G2350A, and CYP11B2 C-344T. By MDR analysis, a three-locus model (ACE ID/ACE G2350A/CYP11B2 C-344T) of gene-gene interaction was the best for predicting ESRD risk, and its maximum testing accuracy was 56.08% and maximum cross-validation consistency was 9/10. ESRD risk was higher with the simultaneous occurrence of ACE I/D DD-ACE G2350A AA. AGT, ACE, and CYP11B2 gene polymorphisms are associated with ESRD. Conclusions. The gene-gene interaction effects of ACE I/D, ACE G2350A, and CYP11B2 C-344T polymorphisms are more important than individual factors for ESRD development among Han Chinese.

Association of ACE I/D polymorphism with obstructive sleep apnea susceptibility: evidence based on 2,228 subjects

BACKGROUND

Whether the insertion/deletion (I/D) polymorphism of the angiotensin-converting enzyme (ACE) gene increases susceptibility to obstructive sleep apnea (OSA) is controversial and still undetermined. Therefore, this meta-analysis was performed to systematically assess the possible association between them.

METHODS

The OVID, Medline, Embase, Web of Science, CNKI, and Wangfang databases were searched to identify eligible studies focusing on the association between ACE polymorphism I/D and susceptibility to OSA.

RESULTS

A total of 2,228 subjects from nine studies were subjected to meta-analysis. Overall, ACE polymorphism I/D had no statistically significant association with increased OSA risk under all genetic models (P > 0.05). In the subgroup analysis by ethnicity or study design, still no significant associations were found for all genetic models (P > 0.05). However, ACE polymorphism I/D was significantly associated with susceptibility to OSA with hypertension in Asians under heterozygous comparison and dominant model. The ID genotype carriers and D allele carriers (ID + DD) were about 53% less likely (odds ratio (OR) = 0.47, 95% confidence interval (CI) = 0.29-0.74; P = 0.001) and about 52% less likely (OR = 0.48, 95% CI = 0.24-0.99; P = 0.047), respectively, to have OSA with hypertension compared to carriers of the II genotype.

CONCLUSIONS

ACE polymorphism I/D had no statistically significant association with increased OSA risk, but the II genotype of ACE may be a risk factor for OSA with hypertension in Asians. OSA cases who develop hypertension may derive from a different mechanism compared to essential hypertension. Studies with large sample size and representative population are warranted to verify this finding.