Involvement of NAD(P)H:Quinone Oxidoreductase 1 and Superoxide Dismutase Polymorphisms in Ulcerative Colitis

Abstract

Inflammatory bowel disease is a multifactorial disease. Oxidative stress has been thought to be one of etiologic factor for inflammatory bowel disease. The genes superoxide dismutase (SOD2) and NAD(P)H:quinone oxidoreductase 1 (NQO1) are involved in inflammation and oxidative stress. The purpose of the present case–control study with 134 patients with ulcerative colitis (UC) and 125 healthy controls was to determine whether polymorphisms of these genes, the NQO1 C609T and the SOD2 Ala-9Val, are associated with the risk of UC and influence the clinical characteristics. These polymorphisms were examined by polymerase chain reaction–restriction fragment length polymorphisms and direct sequencing. In patients showing steroid resistance, the number with the NQO1 T/T genotype was significantly higher than other genotypes (odds ratio 9.45, 95% confidence interval 2.46–41.6, p = 0.002). In the patients whose onset of UC was age 20 years or younger, more patients had SOD2 T/T genotype than the other genotypes (odds ratio 6.46, 95% confidence interval 0.82–51.0). No association between these polymorphisms and UC risk was apparent. The NQO1 C609T polymorphism may influence steroid resistance of UC patients, while the SOD2 Ala-9Val polymorphism may influence age of onset of UC. Oxidative stress may influence the clinical features of UC.