In this paper, two lines of evidence indicate that poly-GA, the most readily detected DPR in the brain and spinal cord of ALS/FTD patients with C9orf72 expanded repeats43,44, significantly contributes to disease phenotypes in C. elegans: (1) poly-GA aggregates and appears to be the most abundantly expressed DPR in our worm models, and (2) mutation of the non-canonical CUG initiation codon selectively decreases poly-GA production, and ameliorates locomotor and lifespan defects in C9ubi and C9neuro animals. This evidence concerns the gene C9orf72 and frontotemporal dementia.