Haploinsufficiency of the gene encoding progranulin (PGRN) leads to frontotemporal lobar degeneration (FTLD) with TAR DNA binding protein 43 (TDP‐43) deposition (FTLD‐TDP) (Baker et al, 2006; Cruts et al, 2006; Neumann et al, 2006). This evidence concerns the gene GRN and frontotemporal dementia.