As expected, ALS cases (n = 152) showed the highest serum neurofilament light chain protein (NfL) concentrations among diagnostic groups, followed by AD patients (n = 111) and then disease controls (n = 99) (Table 1, Fig. 2C, D, Supplementary Tables 2–5, Supplementary Fig. 2). Here, NEFL is linked to amyotrophic lateral sclerosis.