Association between p22PHOX gene C242T polymorphism and hypertension in end-stage kidney disease patients

Oxidative stress plays an important role in hypertension associated vascular damage. It is mediated by nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activation. The C242T polymorphism in the p22PHOX gene encoding essential subunit of NADPH oxidase was associated with CVD, hypertension, and endothelial function. The aim of this study was to assess a potential association of C242T polymorphism with hypertension in end-stage kidney disease (ESKD) patients. DNA samples from 495 patients were genotyped by polymerase chain reaction (PCR) with subsequent cleavage with Rsa I restriction endonuclease. There were no significant differences in genotype and allele distribution between ESKD patients and healthy controls. When patients were stratified into male and female subgroups, there were no differences in the frequency of the T allele (0.35 and 0.34, respectively). Genotype and allele frequencies were also comparable between HY+ and HY- subgroups. We analyzed whether there were any differences between genders in the effect of C242T polymorphism on the presence of hypertension by comparing HY+ males with normotensive males and HY+ females with normotensive females. No difference in polymorphism distribution was found in female subgroup. The significant differences were observed in males. In HY+ subgroup, the frequencies of T allele and TT genotype were higher than in HY- males, with OR 1.91 (1.31-2.8), p = 0.0008 and OR 4.2 (1.67-10.6), p = 0.002, respectively. In conclusion, this is the first study to demonstrate significant association of the p22PHOX gene polymorphism with hypertension in male ESKD patients, with T allele as a risk factor for hypertension.