GRN and frontotemporal dementia: Genetically, familial FTD (fFTD; ∼30% of all FTD-affected individuals) is predominantly linked to mutations in MAPT (MIM: 157140), GRN (MIM: 138945), and C9orf72 (MIM: 614260)9,10; of note, GFRA2 (MIM: 601956) and TMEM106B (MIM: 613413) (previously reported in a cohort with TDP-43 pathology11) were found to be associated with increased risk in a GRN mutation FTD cohort.12