Valosin-containing protein (VCP) associated multisystem proteinopathy (MSP) is a rare and heterogeneous genetic disorder that can cause adult-onset inclusion body myopathy, Paget’s disease of bone (PDB), and frontotemporal dementia (FTD), but other associated manifestations include parkinsonism, amyotrophic lateral sclerosis (ALS), neuropathy, spastic paraplegia, and cardiomyopathy, among others (Table 1). The gene discussed is VCP; the disease is bone Paget disease.