In addition, clinical studies have shown the potential utility of dosing plasma and CSF concentration of the neurofilament light chain (Nfl) to provide specific and prognostic insights in different diseases [consider Lu et al. (2015) for sporadic motor neuron disease and Steinacker et al. (2017), investigating Nfl levels for monitoring progressive aphasia (PPA) variants; Table 1]. The gene discussed is NEFL; the disease is primary progressive aphasia.