Increased vulnerability to oxidative stress-induced cell death and/or reduced antioxidant defenses have been demonstrated in: i) cell lines expressing mutant AβPP, PS1, and PS2 [63–66]; ii) transgenic mice expressing mutant AβPP or PS1, and knockout mice expressing mutant human PS1 [67–74]; iii) fibroblasts and lymphoblasts from patients with familial early onset AD with either PS1 or AβPP mutations [75]; iv) cerebral cortex obtained at autopsy from patients with AβPP and PS1 mutations [76,77]; and v) patients with one or both ApoE ɛ4 alleles [78]. The gene discussed is APP; the disease is Alzheimer disease.