A large number of missense mutations at more than 30 positions in the p97 sequence have been associated with neurodegenerative diseases, including inclusion body myopathy with early-onset Paget disease and frontotemporal dementia (IBMPFD, also referred to as MSP1 or VCP-associated multisystem proteinopathy), amyotrophic lateral sclerosis (ALS), and Charcot–Marie–Tooth disease. This evidence concerns the gene VCP and amyotrophic lateral sclerosis.