C9orf72 and amyotrophic lateral sclerosis: However, C9orf72 knockout mouse models failed to fully recapitulate ALS- or FTD-related neurodegenerative phenotypes, suggesting that loss of C9ORF72 protein is not the only contributor to pathology (Atanasio et al., 2016; Burberry et al., 2016; Burberry et al., 2020; Jiang et al., 2016; Koppers et al., 2015; Lagier-Tourenne et al., 2013; O'Rourke et al., 2016; Panda et al., 2013; Sudria-Lopez et al., 2016; Sullivan et al., 2016; Suzuki et al., 2013; Ugolino et al., 2016; Zhu et al., 2020).