Alternatively, two BAC C9orf72 models did not develop ALS despite the presence of RNA foci and dipeptide repeat proteins that are characteristic of this mutation (O'Rourke et al., 2015; Peters et al., 2015), while a third BAC mouse did exhibit motor deficits and reduced survival, consistent with an ALS disease state (Liu et al., 2016). Here, C9orf72 is linked to amyotrophic lateral sclerosis.