Interactions between ACYP2 genetic polymorphisms and environment factors with susceptibility to ischemic stroke in a Han Chinese Population

CYP11B1 gene polymorphisms and susceptibility to ischemic stroke in a Chinese Han population

Objectives

Ischemic stroke (IS) is the major cause of death and disability. While previous studies confirmed that CYP11B1 is closely associated with IS, the present study aimed to analyze the impact of CYP11B1 gene polymorphisms on the IS susceptibility.

Methods

The present study genotyped six single nucleotide polymorphisms (SNPs) (including rs4736312, rs5017238, rs5301, rs5283, rs6410, and rs4534) of CYP11B1 in peripheral blood samples from IS and control populations. Logistic regression analysis was used to analyze the association between the SNPs and IS risk. The multifactor dimensionality reduction (MDR) method was used to determine the roles of SNP–SNP interactions in IS.

Results

The present study showed that rs5283 was associated with an increased susceptibility to IS [odds ratio (OR) 1.81, p = 0.012]. On the contrary, rs6410 had a protective influence on IS risk (OR 0.56, p = 0.020). Stratified analyses indicated that rs5283 could enhance the risk of IS in subjects aged >63 years (OR 2.41, p = 0.011), of female gender (OR 3.31, p = 0.001), that do not smoke (OR 1.64, p = 0.005), and with hypertension (OR 2.07, p = 0.003). Whereas, rs6410 was related to a lower susceptibility to IS in subjects aged >63 years (OR 0.43, p = 0.032), of female gender (OR 0.30, p = 0.006), do not smoke (OR 0.42, p = 0.017), and with hypertension (OR 0.52, p = 0.022). Besides, rs4736312 reduced the IS susceptibility in non-smokers (OR 0.69, p = 0.031). Rs4534 had a risk-decreasing impact on IS in non-drinking (OR 0.54, p = 0.016). Moreover, the results of the MDR analysis corroborate that the best prediction model for IS was rs5283.

Conclusion

This study revealed that CYP11B1 gene polymorphisms strongly correlated with IS in the Chinese Han population.

Polygenic approaches to detect gene-environment interactions when external information is unavailable

The exploration of 'gene-environment interactions' (G × E) is important for disease prediction and prevention. The scientific community usually uses external information to construct a genetic risk score (GRS), and then tests the interaction between this GRS and an environmental factor (E). However, external genome-wide association studies (GWAS) are not always available, especially for non-Caucasian ethnicity. Although GRS is an analysis tool to detect G × E in GWAS, its performance remains unclear when there is no external information. Our 'adaptive combination of Bayes factors method' (ADABF) can aggregate G × E signals and test the significance of G × E by a polygenic test. We here explore a powerful polygenic approach for G × E when external information is unavailable, by comparing our ADABF with the GRS based on marginal effects of SNPs (GRS-M) and GRS based on SNP × E interactions (GRS-I). ADABF is the most powerful method in the absence of SNP main effects, whereas GRS-M is generally the best test when single-nucleotide polymorphisms main effects exist. GRS-I is the least powerful test due to its data-splitting strategy. Furthermore, we apply these methods to Taiwan Biobank data. ADABF and GRS-M identified gene × alcohol and gene × smoking interactions on blood pressure (BP). BP-increasing alleles elevate more BP in drinkers (smokers) than in nondrinkers (nonsmokers). This work provides guidance to choose a polygenic approach to detect G × E when external information is unavailable.

Single nucleotide polymorphisms in telomere length-related genes are associated with hepatocellular carcinoma risk in the Chinese Han population

Background

Single nucleotide polymorphisms (SNPs) in telomere-related genes are associated with a high risk of hepatocellular carcinoma (HCC). In this study, we investigated the SNPs of telomere length-related genes and their correlation with HCC risk in the Chinese Han population.

Materials and methods

A total of 473 HCC patients and 564 healthy volunteers were recruited. Overall, 42 SNPs distributed in telomere-related genes were selected and identified. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated.

Results

We found rs6713088 (OR = 1.27, 95% CI = 1.07-1.52, p = 0.007), rs843711 (OR = 1.29, 95% CI = 1.09-1.54, p = 0.004) and rs843706 (OR = 1.30, 95% CI = 1.09-1.55, p = 0.003) in the ACYP2 gene, rs10936599 (OR = 1.21, 95% CI = 1.02-1.44, p = 0.032) in the TERC gene and rs7708392 (OR = 1.24, 95% CI = 1.00-1.52, p = 0.042) in the TNIP1 gene were associated with high HCC risk (OR > 1). In contrast, rs1682111 (OR = 0.77, 95% CI = 0.64-0.94, p = 0.008) in the ACYP2 gene, rs2320615 (OR = 0.79, 95% CI = 0.64-0.99, p = 0.038) in the NAF1 gene, rs10069690 (OR = 0.75, 95% CI = 0.59-0.96, p = 0.021) and rs2242652 (OR = 0.70, 95% CI = 0.55-0.90, p = 0.004) in the TERT gene were associated with low HCC risk (OR < 1). Based on genotype frequency distributions, rs6713088, rs843645, rs843711 and rs843706 located in the ACYP2 gene as well as rs10936599 in the TERC gene were associated with a high incidence of HCC (p < 0.05). In addition, SNPs in these genes could form a linkage imbalance haplotype. Specifically, the haploid 'GC' formed by rs10069690 and rs2242652 within the TERT gene increased the risk of HCC (p < 0.05).

Conclusion

SNPs in ACYP2, TERC, TERT and other genes were correlated with HCC risk in the Chinese Han population. These data may provide new insights into early diagnosis and screening of HCC.

Family History, Tobacco Smoking, and Risk of Ischemic Stroke

BACKGROUND AND PURPOSE

Both genetic factors and smoking are associated with ischemic stroke (IS) risk. However, little is known about the potential interaction of these factors. We aimed to assess whether smoking and a positive family history interact to increase the risk of IS.

METHODS

The nationwide prospective study recruited 210,000 men and 300,000 women in 2004 to 2008 at ages 30 to 79 years. During 9.7 years of follow-up, we documented 16,923 and 20,656 incident IS cases in men and women without major chronic diseases at baseline, respectively. Multivariable Cox regression models were used to examine associations between family history and IS. Likelihood ratio tests were used to test the smoking-family history interactions on IS.

RESULTS

About 67.8% (n=135,168) of men ever smoked regularly compared with 2.7% (n=7,775) of women. Among men, a significant interaction between family history and smoking on IS was observed (P for interaction=0.03), with more pronounced association between family history and IS among ever-regular smokers (hazard ratio [HR], 1.21; 95% confidence interval [CI], 1.16 to 1.27) than among never-smokers (HR, 1.11; 95% CI, 1.01 to 1.23). The association between family history and IS among ex-smokers after more than 10 years of cessation (HR, 1.01; 95% CI, 0.85 to 1.20) appeared similar to that among never-smokers. Among women, a similar but not significant interaction between family history and smoking on IS was observed. Ever-regular smokers who had a family history of stroke had the highest risk of IS.

CONCLUSIONS

Among Chinese men, the association of family history with IS was accentuated by smoking, and such accentuation tended to be lowered by cessation.