MMP9 and osteopetrosis: Notably, we found three PSGs were linked to the disease “osteopetrosis” in mice or humans, including CSF1R, LRRK1, and MMP9. We also observed eleven PSGs associated with the regulation of circadian rhythm (e.g., BMAL2, BTBD9, MYBBP1A, NFIL3, and ZFHX3) (Figure 2D).