Although serum IL-20 level was upregulated in both IL-20R1+/+ and IL-20R1−/− mice after bone fracture, we found that IL-20 level was significantly higher in IL-20R1+/+ mice than in IL-20R1−/− mice between 5 and 21 days post-fracture (Fig. 2a). The gene discussed is IL20; the disease is bone fracture.