CSF levels of neurofilament light (NFL) proteins have been found normal in PD patients (Constantinescu et al., 2010; Hall et al., 2012), and increased in patients with PSP (Holmberg et al., 1998; Constantinescu et al., 2010; Hall et al., 2012), MSA (Holmberg et al., 1998; Constantinescu et al., 2010; Hall et al., 2012), CBD (Constantinescu et al., 2010; Hall et al., 2012), and PDD (Hall et al., 2012). This evidence concerns the gene NEFL and Parkinson disease.