C9orf72 and frontotemporal dementia: The Ran gradient and its associated regulatory proteins such as RCC1 are disrupted in multiple C9ORF72-associated ALS/FTD models, including long differentiated iPSC-neurons, induced neurons of carriers, and Drosophila models expressing G4C2 repeats (Freibaum et al, 2015; Jovicic et al, 2015; Klebe et al, 1995; Zetsche et al, 2015).