Mutations in MAPT and GRN typically present as FTDphenotypes, whereas hexanucleotide repeat expansions in C9orf72 areassociated with FTD and MND (Figure 1).Mutations in other genes, such as in those encoding TDP-43 (TARDBP)or FUS (FUS) also present clinically as FTD and/or MND.12 This evidence concerns the gene C9orf72 and frontotemporal dementia.