NEFL and Parkinson disease: Elevated levels of NfL have been described in many neuroaxonal damage conditions such as HIV-associated dementia, amyotrophic lateral sclerosis (ALS), Creutzfeldt-Jakob disease, multiple sclerosis (MS), multi-system atrophy, cortico-basal degeneration, progressive supranuclear palsy, traumatic brain injury, fronto-temporal dementia, normal pressure hydrocephalus, dementia with Lewy bodies, Alzheimer dementia, and Parkinson’s disease associated with dementia [49].