The utility of alpha-synuclein as biofluid marker in neurodegenerative diseases: a systematic review of the literature

Abstract

The discovery of alpha-synuclein (alpha-syn) as a major component of Lewy bodies, neuropathological hallmark of Parkinson's disease (PD), dementia with Lewy bodies and of glial inclusions in multiple system atrophy initiated the investigation of alpha-syn as a biomarker in cerebrospinal fluid (CSF). Due to the involvement of the periphery in PD the quantification of alpha-syn in peripheral fluids such as serum, plasma and saliva has been investigated as well. We review how the development of multiple assays for the quantification of alpha-syn has yielded novel insights into the variety of alpha-syn species present in the different fluids; the optimal preanalytical conditions required for robust quantification and the potential clinical value of alpha-syn as biomarker. We also suggest future approaches to use of CSF alpha-syn in neurodegenerative diseases.