Many genes have been identified in the development of ALS and FTLD, including TDP-43, FUS, and C9orf72, indicating that these two disorders comprise a spectrum of diseases (Seelaar et al., 2011; Renton et al., 2014; Riku et al., 2014b; Hayes and Rothstein, 2016). The gene discussed is C9orf72; the disease is amyotrophic lateral sclerosis.