High BACE1 concentrations (probably reflecting gene expression levels) and enzymatic activity were found in human AD brain extracts, consistent with experimental evidence that neurons express higher levels of Aβ in AD compared to “cognitively healthy aging.” In addition, a relatively large accumulation of BACE1 was found in neuritic dystrophies in close proximity of Aβ plaques both in AD amyloidogenic transgenic mouse models and in AD brains, and this presence may promote cyclic Aβ production [3, 5, 6]. The gene discussed is BACE1; the disease is Alzheimer disease.