Emerging evidence highlights the diagnostic and prognostic potential of other biomarkers associated with PD pathophysiology beyond α-synuclein and dopamine, including glucocerebrosidase (GCase) [13,14,15], glial fibrillary acidic protein (GFAP) [16,17], neurofilament light chain (NfL) [18], DJ-1 [19,20], and others [21]. This evidence concerns the gene NEFL and Parkinson disease.