Since MAPT was first identified as the causative gene of FTD in 1998, an increasing number of pathogenic genes have been reported associated with FTD including GRN, C9orf72, VCP, SQSTM1, CHMP2B, TBK1, OPTN, TARDBP, CHCHD10, UBQLN2, and DCTN1 (Pottier, Ravenscroft, Sanchez‐Contreras, & Rademakers, 2016). This evidence concerns the gene OPTN and frontotemporal dementia.