Cerebrospinal Fluid Amyloid-ß Subtypes in Confirmed Frontotemporal Lobar Degeneration Cases: A Pilot Study.

To investigate amyloid-ß (Aß) in frontotemporal dementia (FTD), cerebrospinal fluid (CSF) Aß38, Aß40, and Aß42 in frontotemporal lobar degeneration (FTLD; N = 18 genetically and/or pathologically confirmed and N = 8 FTD with concomitant amyotrophic lateral sclerosis) were compared with Alzheimer's disease (AD; pathological or Pittsburgh-compound-B Positron-emission-tomography (PIB-PET) positive; N = 25) and controls (N = 24). For all the Aß subtypes, group difference was seen and post-hoc analysis revealed lower levels in FTLD compared to controls (p≤0.05). Aß42/40 ratio showed no difference between FTLD and controls; however, a difference was seen between AD versus FTLD (p < 0.01). This is an intriguing finding, suggesting a possible role of Aß in FTLD pathogenesis.