C9orf72 and frontotemporal dementia: In the present study, we aimed to describe the relationship between the frequency and severity of behavioral and neuropsychiatric symptoms and disease progression in each of the main genetic variants associated with FTD, namely C9orf72, GRN, and MAPT. We observed in a large cohort of well-defined patients from the international GENFI study that frequencies and severity of behavioral symptoms may overlap and also differ significantly between gene variants.