Cerebrospinal beta-amyloid (1-42) in early Alzheimer's disease:: association with apolipoprotein E genotype and cognitive decline

The concentration of beta-Amyloid((1-42)) protein (A beta 42) in cerebrospinal fluid (CSF) was determined in 75 Alzheimer's disease (AD) patients, 35 patients with other causes of dementia and 30 cognitively healthy age-matched controls. A significant decrease of A beta 42 concentration was found in AD patients, even in 25 subjects with very mild dementia as compared to patients with other causes of dementia and controls. Within AD patients we observed a significant decline of A beta 42 from very mild to mild and moderate dementia. In addition, A beta 42 levels were negatively correlated with the severity of cognitive impairment and with the number of epsilon 4 alleles inherited. We conclude that measurement of A beta 42 in CSF might be helpful for identifying AD at an early stage and also for tracking the clinical course. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.