In 2006, the second FTD-related gene on chromosome 17 was discovered in the progranulin (GRN) gene (Baker et al., 2006; Cruts et al., 2006), accounting for even more cases than mutations in MAPT explaining all the 17q21-linked autosomal-dominant FTD cases not accounted for by MAPT mutations (www.molgen.ua.ac.be/ADMutations/). Here, MAPT is linked to frontotemporal dementia.