To confirm the novel finding that cryptic peptides reflecting TDP-43 loss of function are detectable in presymptomatic disease, we analyzed an additional cohort of largely presymptomatic C9orf72 mutation carriers from the Dominant Inherited ALS (DIALS) Network to further characterize early loss of TDP-43 splicing repression. This evidence concerns the gene C9orf72 and amyotrophic lateral sclerosis.