We have demonstrated that genes of antioxidant defense enzymes (ADE), such as glutamate cysteine ligase (GCLM) [25], glutathione peroxidase (GPX1) [26], catalase (CAT) [27], myeloperoxidase (MPO) [28], NADPH oxidase (CYBA, p22phox subunit) [29, 30], NAD(P)H: quinone oxidoreductase type 1 (NQO1) [31] and microsomal epoxide hydrolase (EPHX1) [19], are important determinants of genetic susceptibility to asthma in Russians. The gene discussed is NQO1; the disease is asthma.