Compared with prodromal GRN variation carriers, participants with symptomatic FTD had more severe scores on the CDR plus NACC FTLD sum of boxes, Clinical Global Impressions Scale-severity, and Frontotemporal Dementia Rating Scale, as well as elevated CSF NfL and CSF t-tau level, but did not otherwise differ demographically. This evidence concerns the gene GRN and frontotemporal dementia.