These observations prompted the present retrospective study, carried out in a large cohort of FTD patients sub-grouped according to the global CDR plus NACC FTLD scale, which was aimed at (1) characterizing the clinical and behavioural features of prodromal FTD, as compared to more advance stages of FTD; (2) defining the rate of conversion of prodromal FTD to fully symptomatic disease at one-year follow-up; and (3) assessing the predictors of progression, considering serum NfL levels. The gene discussed is NEFL; the disease is frontotemporal dementia.