C9orf72 and dementia: We hypothesized that (1) GRN and C9orf72 mutation carriers would have an increased burden and rate of progression of NPS prior to the onset of dementia compared to their family members who do not carry the respective mutation (non-carriers), (2) that pre-dementia NPS measures would be associated with specific patterns of GM volume loss and/or WMSA on structural MRI, and (3) that there would be distinct NPS profiles and corresponding imaging changes between the two mutation carrier groups.