Background: Oxidative stress induced by the superoxide anion (.O2-) has been implicated in atherogenesis. The NADH/NADPH oxidase system is involved in.O2- production and p22 phox is an essential component of that system.
Material and methods: We analysed the p22 phox C242T polymorphism in 689 consecutive Australian Caucasians aged </= 65 years with and without angiographically documented coronary artery disease (CAD) RESULTS: We report the rare T allele frequency of 0.33, which is 3 fold higher than that reported in the Japanese population by Inoue et al. . The genotype distributions were not different among patients with CAD (CC:0.422, CT:0.459 and TT: 0.119 in men; 0.447, 0.439 and 0.114 in women) and without CAD (0.479, 0. 420 and 0.101%, chi2 = 0.794, P = 0.672 in men; 0.443, 0.471 and 0. 86, chi2 = 0.442, P = 0.802 in women). The frequencies of the rare TT homozygotes or of the 'T' allele frequency were also not associated with the number of significantly stenosed vessels (chi2 = 4.466, P = 0.614 in men; chi2 = 4.736, P = 0.578 in women) or with a myocardial infarction (MI) history (chi2 = 2.310, P = 0.315 in men; chi2 = 1.178, P = 0.555 in women). However, when the analysis was conducted in young male patients aged </= 45 years (n = 44), TT + TC patients tended to have an increased risk for CAD (odds ratio: 5.71 95% CI: 1.22-26.75, P = 0.0271).
Conclusion: The p22 phox C242T polymorphism is not associated with the occurrence or severity of CAD or with a history of MI in Australian Caucasian patients aged </= 65 years. However, the polymorphism could be associated with an increased CAD risk in young patients, which requires confirmation in large populations.