Our findings of the lack of effect of SOD1-G93A or α-Syn on poly(GR) and the lack of effect of FUS or TDP-43 on poly(GA), the translation of which may not be associated with ribosome stalling (39), strongly support the specificity of the genetic relationships among FUS, TDP-43, and C9-ALS/FTD-associated poly(GR) identified in this study. This evidence concerns the gene C9 and frontotemporal dementia.