GFAP and Parkinson disease: Besides those studied in this work, additional biomarkers that may change in the context of PD development include malondialdehyde, which level increases with elevated oxidative stress, DJ-1 protein (associated with oxidative stress and neuroprotection), NfL (neurofilament light chain, neuronal protein released during axonal damage), tau proteins, glial marker GFAP, miRNAs, and others [88,89,90,91].