Additionally, transcriptional levels of bone-associated factors (RANKL, OPG, RANKL/OPG ratio, ALP, PTH1R, COL1A1, and COL17A1) were consistently upregulated in RA-hOBs but not in H-hOBs at either time point (Figure 5E). The gene discussed is COL1A1; the disease is rheumatoid arthritis.