APOE and Alzheimer disease: Also after exclusion of AD patients, CSF AChE activity was lower in participants that were homozygous in terms of the APOE ε4 allele compared to subjects lacking the APOE ε4 allele [median (25th -75th percentile) in homozygous patients: 23.1 (17.8-25.7) mU/mL vs. in patients lacking APOE ε4 allele: 40.3 (31.8-43.5) mU/mL, P = 0.002].