The “cholinergic hypothesis of AD” postulates that learning and memory deficits result from the loss of cholinergic innervation to the entorhinal cortex and hippocampus from nuclei in the basal forebrain, which may be partially recovered by elevating acetylcholine (ACh) levels, through the inhibition of the ACh catabolising cholinesterases (Bartus et al., 1982; Francis et al., 1999). Here, BCHE is linked to Alzheimer disease.