Validation of Serum Neurofilament Light Chain as a Biomarker of Parkinson’s Disease Progression

Objective: To assess neurofilament light chain (NfL), as a biomarker for Parkinson9s disease (PD). Methods: We quantified NfL in (1) longitudinal CSF samples from PD, other cognate/neurodegenerative disorders (OND), and healthy controls (HC); (2) a cross-sectional cohort with paired CSF and serum samples from participants with PD, OND, and HC, and (3) a large longitudinal validation cohort with serum samples from PD, OND, HC, prodromal conditions, and mutation carriers. Results: In the longitudinal discovery cohort (1) NfL in CSF was highest in OND and higher in PD vs. HC across all visits (p