VASN and chondrodysplasia: SLC26A2 is a sulfate transporter and its mutation causes chondrodysplasia (Forlino et al., 2005), whilst vasorin is a TGF-β-binding protein that inhibits TGF-β signaling, which is known to have crucial roles in joint homeostasis (Ikeda et al., 2004; Shen et al., 2014).