C9orf72 and amyotrophic lateral sclerosis: These analyses revealed that in patients with ALS (with or without concurrent FTD), the CSF levels of τP-181 were lower in C9orf72 repeat expansion carriers compared to non-carriers, whereas levels of TDP-43, Aβ42 and τT and the τP-181/τT ratio did not differ between the two groups (Figure 2).