VCP mutations are found in less than 2% of FTD cases and areresponsible for 50-75% of cases of familial MSP.21,89,91 The onset of symptoms of myopathy (mean age 43years) and Paget disease (mean age 42 years) usually occur earlier than the onset ofFTD symptoms (mean age 55 years).90 Mutation carriers can develop all three phenotypes (12%), acombination of two phenotypes (50%) or only one of the phenotypes (38%).90 Only 3% develop FTDalone.90 This evidence concerns the gene VCP and frontotemporal dementia.