UBQLN2 and bone Paget disease: However, other genes are associated with rare FTD cases, such as valosin-containing protein (VCP) mutations, which are linked to a specific condition called inclusion body myopathy with Paget disease of the bone and FTD (IBMPFD)9,10, charged multivesicular body protein 2B (CHMP2B), which is involved in the endosomal–lysosomal pathway11,12, fused in sarcoma (FUS)13,14, TAR DNA-binding protein (TARDBP)15,16, sequestosome 1 (SQSTM1)17–20, TANK­binding kinase 1 (TBK1)21–24, and ubiquilin 2 (UBQLN2)25–27.