In addition, several gene polymorphisms in genes encoding molecules with a role in the redox balance, such as glutathione S-transferase M1/glutathione S-transferase T1, paraoxonase-1, methylentetrahydrofolatereductase, glutathione S-transferase and catalase were upregulated or more frequently expressed in psoriasis [67,68,69,70,71,72,73,74]. This evidence concerns the gene PON1 and psoriasis.