More than 45 missense mutations in VCP have been identified in multiple neurodegenerative diseases, including inclusion body myopathy associated with Paget disease of the bone and frontotemporal dementia (IBMPFD; also referred to as multisystem proteinopathy MSP1), amyotrophic lateral sclerosis (15), and tauopathy (16, 17), indicating the importance of VCP function for neuronal health. This evidence concerns the gene VCP and inclusion body myopathy with Paget disease of bone and frontotemporal dementia.