Besides the aberrant aggregation of transactive response DNA-binding protein of 43 kDa (TDP-43) (5, 70), the nuclear-to-cytoplasmic mislocalization of fused in sarcoma (FUS) protein in motor neurons has been identified as another pathogenic feature of VCP-mutated ALS, which was ascribed to the increased intron retention (IR) in splicing factor proline and glutamine rich (SFPQ) transcripts (71, 72). This evidence concerns the gene VCP and amyotrophic lateral sclerosis.