SCUBE3, which acts as an endogenous ligand for TGFβ-receptor 2 [15], is a valid candidate for regulating osteoclast recruitment: it is expressed by osteoblasts [16] (Supplementary Fig. 3E), its inactivation results in a syndrome characterised by impaired ossification in humans and mouse models [17, 18], and it is linked to Paget’s disease of bone which is characterised by numerous large osteoclasts [16]. This evidence concerns the gene SCUBE3 and bone Paget disease.