Because a complex of UBXD1-p97 is required for recruitment of ubiquitylated caveolin-1 to the lysosome for degradation this pathway becomes impaired in the disease mutants, leading to the accumulation of caveolin-1 positive endolysosomes in IBMPFD patients (Ritz et al., 2011). The gene discussed is CAV1; the disease is inclusion body myopathy with Paget disease of bone and frontotemporal dementia.