In this study, we assessed the accumulation of WMSAs and the alterations of DTI parameters in predementia carriers of GRN and C9orf72 mutations, leveraging MRI data from the University of British Columbia (UBC) familial frontotemporal dementia study.21 We hypothesized that (i) GRN+ carriers would have a higher rate of WMSA accrual compared with C9orf72+ carriers, or family members who do not carry the mutations (C9orf72− and GRN−; noncarriers) and that (ii) the level of DTI parameter alterations would be higher in GRN+ and C9orf72+ carriers compared with the noncarriers. The gene discussed is C9orf72; the disease is frontotemporal dementia.