First, ΔNLS-FUS tg mice, previously shown to exhibit the toxic gain of function ALS phenotype (Shiihashi et al., 2016), also recapitulate several aspects of FTD phenotypes, hyperactivity, social interactional deficits, and impaired fear memory retrieval before the appearance of progressive motor deficits (Fig. 2), establishing them as a novel ALS-FTD mouse model. This evidence concerns the gene FUS and frontotemporal dementia.