In the past 9 years, considerable progress has been made toward unraveling the genetic causes of FTLD, with apparently all common FTD-related genes discovered, comprising C9orf72, MAPT, GRN, TARDBP, VCP, CHMP2B, and FUS, currently identifying 50–60% of the familial forms of FTD, although rare mutations in other genes could explain a small number of the remaining families (Rademakers et al., 2012; Le Ber, 2013). This evidence concerns the gene C9orf72 and frontotemporal dementia.