Cholinergic deficits are associated with the loss or derangement of nicotinic acetylcholine receptors (nAChRs) in the brains of those with AD and Down syndrome (Engidawork et al., 2001), with significantly decreased alpha 7 and significantly increased alpha 3 receptors in the frontal cortex in AD. This evidence concerns the gene PSMA3 and Alzheimer disease.