In addition to FTD, CSF NFL was validated as a screening biomarker for inflammatory disease [4], Creutzfeldt-Jakob disease (CJD) [5], acute neuronal ischemia [6], Alzheimer’s disease (AD) [1,7], Parkinson’s disease (PD) [8], multiple sclerosis (MS) [9] and traumatic brain injury [10,11]. Here, NEFL is linked to Parkinson disease.