The MAPT gene was the first FTD locus to be identified (reviewed in Sieben et al., 2012), and mutations in the gene encoding TDP-43 (TARDBP) can give rise to MND (Sreedharan et al., 2008) and FTD in rare instances (Borroni et al., 2010). Here, MAPT is linked to frontotemporal dementia.