C9orf72 and frontotemporal dementia: In C9ORF72-ALS/FTD, arginine-containing dipeptide repeat proteins (R-DPRs), poly-GR and poly-PR, bind to ribosomal subunits, inhibiting global protein synthesis (Hartmann et al, 2018; Kanekura et al, 2016; Loveland et al, 2022; Moens et al, 2019; Zhang et al, 2018b).