AD is mainly caused by cholinergic neuron loss and progressive decline in acetylcholine (ACh) in the forebrain9,10, the activity of ACh in the brain is terminated by the hydrolysis of two cholinesterase (ChEs), namely acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). This evidence concerns the gene BCHE and Alzheimer disease.