C9orf72 and amyotrophic lateral sclerosis: Expansions of G4C2 which are translated to form DPRs have been shown in Drosophila models and C9orf72-ALS iPSC derived neurons to disrupt nucleocytoplasmic transport (NCT), both export of nuclear RNA and import of nuclear proteins, through binding to many of the nuclear pore complex proteins (Freibaum et al., 2015).