CSF levels of tau, beta-amyloid(1-42) and GAP-43 in frontotemporal dementia, other types of dementia and normal aging

Cerebrospinal fluid (CSF) levels of tau, beta-amyloid(1-42) and growth-asso ciated protein 43 (GAP-43) were studied in patients with frontotemporal dem entia (FTD; n = 17), Alzheimer's disease (AD; n = 60), subcortical white-ma tter dementia (SWD; n = 24), Parkinson's disease (PD; n = 23) and dysthymia (n = 19) and in age-matched controls (n = 32). CSF-tau was significantly i ncreased only in AD, and CSF-beta-amyloid(1-42) was significantly decreased in AD and SWD as compared to controls, and in AD compared to FTD. CSF-GAP- 43 was significantly decreased only in PD. The GAP-43/tau ratio was decreas ed in all the patient groups except the dysthymia group compared to control s. A positive correlation was found between CSF-GAP-43 and CSF-tau in all g roups. The results suggest normal levels of CSF-tau and CSF-beta-amyloid(1- 42) in FTD, which will aid in the clinical separation of FTD from AD. In SW D, decreased levels of CSF-beta-amyloid(1-42) suggest concomitant involveme nt of vascular and amyloid protein mechanisms.