VCP and amyotrophic lateral sclerosis: A literature search was conducted using the terms “NEK1”, “C21ORF2”, “CCNF”, “VCP”, and “ALS” in PubMed, with the references therein further analyzed to gather information on the molecular mechanisms of ALS pathogenesis associated with mutations in various genes, including NEK1, C21ORF2, CCNF, and VCP.