SQSTM1 and bone Paget disease: Considering the facts that two independent genes linking to forms of Paget disease of bone; VCP for IBMPFD and SQSTM1 for PDB, are also associated with ALS and/or ALS-FTD, and that both VCP and p62 are key regulators for the autophagy-endolysosomal system, dysregulation of such VCP/p62-associated common pathological pathways might account for these seemingly different diseases.