Significantly, RNA processing defects, such as intron retention (Luisier et al., 2018) and mRNA instability (Tank et al., 2018), have been observed in FUS or TDP-43 fALS as well as sALS MN, indicating that ALS models harboring these mutations may provide insights into the molecular mechanisms of both fALS and sALS. This evidence concerns the gene FUS and amyotrophic lateral sclerosis.