Acetylcholinesterase (AChE) is contained in all the vulnerable central nervous system (CNS) neurons prone to neurodegeneration, irrespective of the transmitter they use: we have therefore proposed that the neurotoxic actions of the C-terminal peptides derived from AChE as a signal molecule could be the common mechanism for Parkinson’s disease, Motor neurone disease and AD [2]. The gene discussed is ACHE; the disease is Parkinson disease.