The expression of Cu-dependent enzymes, such as Cu/Zn SOD1 and antioxidant protein 1 (ATOX1), was markedly reduced in multiple microarray studies of AD patients, reinforcing the notion that a lack of Cu, by reducing host antioxidant defenses, plays a pivotal role in AD pathology [108,109]. This evidence concerns the gene PRDX3 and Alzheimer disease.