AMYLOID-BETA PROTEIN-LEVELS IN CEREBROSPINAL-FLUID ARE ELEVATED IN EARLY-ONSET ALZHEIMERS-DISEASE

The 4-kd amyloid beta protein (A beta) deposited as amyloid in Alzheim er's disease (AD) is produced and released by normal proteolytic proce ssing of the amyloid beta protein precursor (beta APP) and is readily detected in cerebrospinal fluid (CSF). Here, we present the levels of A beta in CSF from a total of 95 subjects, including 38 patients with AD, 14 with early-onset AD and 24 with late-onset AD, 25 normal contro l subjects, and 32 patients with other neurological diseases. The leve l of A beta decreased with normal aging, and there was a significant e levation in the level of A beta in the CSF of early-onset AD patients (4.14 +/- 1.37 pmol/ml, p < 0.01). Neither Mini-Mental State nor Funct ional Assessment Staging were correlated with the amount of A beta in the CSF. The A beta/secreted form of beta APP ratio was elevated, but the level of alpha 1-antichymotrypsin in the CSF did not correlate wit h the level of CSF A beta in early-onset AD patients. Thus, the level of A beta in the CSF is elevated in early-onset AD patients acid is su ggested to be correlated with the pathology in the brain that characte rizes AD.