C9orf72 and amyotrophic lateral sclerosis: Given the greater nuclear distribution of G4C2 repeat RNA after stress induction, we evaluated whether there was any significant overlap between endogenous G4C2 repeat RNA and TDP-43, a critical factor in C9orf72 ALS/FTD pathology and ALS pathogenesis as well as a robust marker for nuclear bodies [16, 78].