ACHE and Alzheimer disease: Studies revealed that the level and distribution of AChE isoforms are different in AD: in the frontal cortex of AD patients where amyloid aggregates are usually found, an elevated level of abnormally glycosylated AChE isoforms was found, which was not the case in the cerebellum where amyloid accumulation is absent (Appleyard and McDonald, 1992; Saez-Valero et al., 1999).