FUS and frontotemporal dementia: The leading cause for ALS and FTD is a hexanucleotide repeat expansion in intron 1 of C9orf72 (DeJesus-Hernandez et al., 2011; Renton et al., 2011), while mutations in several RNA-binding proteins including fused in sarcoma (FUS) and TAR DNA-binding protein 43 (TDP-43, encoded by the TARDBP gene) indicate that disruption of RNA metabolism is a key pathomechanism (Zhao et al., 2018).