Blood NfL levels resulted higher in a mixed cohort of 58 CBS and PSP patients and a cohort of 12 CBS patients when compared to, respectively, 72 and 26 healthy controls (p < 0.001), 116 and 20 PD patients (p < 0.001) [20, 27]; furthermore, blood NfL levels resulted higher in 40 CBS patients than in 101 PSP patients (p < 0.001) [34]. This evidence concerns the gene NEFL and Parkinson disease.