GRN and frontotemporal dementia: To date a handful of genes has been associated with FTD: besides MAPT, GRN and C9orf72 (found in 2–11 %, 5–11 % and 7–20 % of cases, respectively) [11, 12], genetic variability in other genes, including CHMP2B, valosin containing protein (VCP), sequestosome 1 (SQSTM1) and ubiquilin 2 (UBQLN2), is extremely rare [3, 11].