TMEM97 and early-onset autosomal dominant Alzheimer disease: While there are several proteins and pathways implicated in contributing to age-related diseases, the sigma-2 receptor (S2R) acts as a regulator of cellular damage associated with certain age-related degenerative diseases of the central nervous system, including Alzheimer’s disease, Parkinson’s disease, dementia with Lewy bodies, and dry age-related macular degeneration (dry AMD).