The butyrylcholinesterase K variant is not associated with Alzheimer's disease

Alzheimer's disease is characterized by different features, one of them bei ng an overexpression of acetylcholine esterase in the brain. This enzyme, t ogether with the butyrylcholinesterase (BChE), is a member of the serine hy drolase family. It has been suggested that BChE regulates the synaptic conc entration of acetylcholine in the brain. The gene coding for BChE contains many polymorphic variants, the K variant being associated with a lower enzy matic activity. This variant has been reported to be associated with Alzhei mer's disease in carriers of the apolipoprotein E (apoE) epsilon 4 allele, the association being stronger in patients aged 75 years and over. In the p resent study dealing with a Caucasian population composed of 336 AD patient s compared to 344 age-matched controls, we did not observe any association between the BChE-K variant, either alone or in apoE epsilon 4 carriers, and the disease. A pooled analysis from nine studies definitely excludes any a ssociation between BChE-K and AD.