In patients with AD and PDD, there is often an increase in lipid hydroperoxide (L-OOH) and malondialdehyde (MDA) activity, alongside decreased activity of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH) (Chen et al., 2022; Atiq et al., 2023). The gene discussed is CAT; the disease is Alzheimer disease.