ATXN2 and frontotemporal dementia: Mutations in TDP-43 or FUS lead to ALS/FTD (Lagier-Tourenne et al., 2010; Vance et al., 2009), while mutations in Ataxin-2 can cause spinocerebellar ataxia type 2 or ALS (Elden et al., 2010; Gispert et al., 1993).