Given the similarities in the skeletal distribution between FD and PDB and the possible presence of SQSTM1/P392L somatic mutations in pagetic bone lesions, we hypothesized that the optimization of the PCR method, developed to detect GNAS post-zygotic mutations in FD, would allow us to detect SQSTM1/P392L post-zygotic mutations in the peripheral blood of patients with PDB. Here, GNAS is linked to Fabry disease.