NEFL and Parkinson disease: Other major potential CSF biomarkers studied include DJ-1, whose mutations are a rare cause of PD (Hong et al. 2010), Aβ42, which seems to correlate with cognitive impairment, and different forms of tau and neurofilament light chains that might help to differentiate PD from other α-synucleinopathies (such as MSA) and primary tauopathies (PSP and CBD) (Magdalinou et al. 2014).