Furthermore, low CSF level of NfL (cNfL) have been found in presymptomatic carriers of genetic FTD in contrast to high concentration in the symptomatic ones (Scherling et al., 2014; Meeter et al., 2016): in FTD GRN, MAPT or C9orf72 mutation carriers, cNfL levels have reached a 8-fold higher increase in the affected patients than in presymptomatic carriers. Here, C9orf72 is linked to frontotemporal dementia.