In contrast, a different degree of redundancy (antagonism) in gene-gene interactions was observed between the CAT −21A>T and GPX2 G>A loci in men and between the EPHX1 Y113H and IL5 loci C-703T in women with allergic asthma, as well as between the GPX1 P198L, GPX2 G>A, EPHX1 Y113H, and IL5 C-703T loci in women with nonallergic asthma. This evidence concerns the gene CAT and allergic asthma.