To provide further support for this notion, we found that p62, a known substrate of the autophagy pathway that is a component in neuronal inclusions in C9ORF72 patients [4], significantly accumulated in human neurons with GGGGCC repeat expansions but not in neurons derived from control iPSCs or neurons derived from iPSCs of an FTD patient with a progranulin mutation (Fig. 7d). Here, GRN is linked to frontotemporal dementia.