Regarding the environmental factors, we and others have shown that chronic stress might contribute to AD (reviewed also in [8–10]) via (a) sustained corticotropin-releasing hormone and cortisol effects in brain cells [11], and (b) chronic increases in systemic and brain levels of inflammatory cytokines (such as tumor necrosis factor (TNF) [12]; the latter, as components of innate immunity, are increasingly recognized for their neuroinflammatory roles in AD [13, 14]. This evidence concerns the gene TNF and Alzheimer disease.