GRN and frontotemporal dementia: PGRN and GRNs came to the attention of the neuroscience field in 2006, when autosomal dominant mutations in the GRN gene were discovered as a common cause of frontotemporal dementia (FTD) with inclusions of the TAR DNA-binding protein 43 (TDP-43; Baker et al., 2006; Cruts et al., 2006; Gass et al., 2006).