CHAT and early-onset autosomal dominant Alzheimer disease: In post-mortem analysis of patients with Alzheimer's Disease, there is a clear loss of cholinergic neurons (Mufson et al., 2007), and a significant reduction in cholinergic enzymes, choline acetyltransferase (ChAT) and acetyl-cholinesterase (AChE) (DeKosky et al., 1992).