The association of CYP1A1 genetic polymorphisms and additional gene–gene interaction with ischemic stroke in the eastern Han of China

The aim of this study was to investigate the association between CYP1A1 gene polymorphism and ischaemic stroke (IS) risk, and the impact of gene–gene interaction on IS risk based on a Chinese Han case–control study. A total of 1162 subjects (612 men and 550 women), with a mean age of 63.1 ± 12.5 years old, were selected, including 580 IS patients and 582 normal controls. Logistic regression was performed to investigate association between single-nucleotide polymorphisms (SNP) and IS risk, and generalized multifactor dimensionality reduction (GMDR) was used to analyze the gene–gene interaction. Logistic regression analysis showed that the frequency for rs4646903 minor alleles was lower in cases than that in normal controls, and C allele of rs4646903 was 20.7 % in ischemic stroke cases and 27.1 % in controls subjects ( p < 0.001). Logistic analysis showed the significant association between genotypes of variants in rs4646903 and decreased ischemic stroke risk. GMDR analysis indicated that there was a significant two-locus model ( p = 0.0107) involving rs4646903 and rs1048943, indicating a potential gene–gene interaction between rs4646903 and rs1048943. Overall, the two- locus models had a cross-validation consistency of 9 of 10, and had the testing accuracy of 60.72 %. Subjects with TC or CC of rs4646903 and AG or GG of rs1048943 genotype have lowest ischemic stroke risk, compared to subjects with TT of rs4646903 and AA of rs1048943 genotype, and OR (95 % CI) was 0.63 (0.42–0.89). rs4646903 minor alleles and interaction between rs4646903 and rs1048943 were associated with decreased IS risk.