Similarly, CLOCK expression was delayed 1.4 hours (p<0.05) in RA fibroblasts and the relative expression was constantly lower (p<0.05) in RA cells and NPAS2 expression was delayed 1.9 hours (p = 0.05) but was constantly higher in RA fibroblast (p = 0.01) than in OA fibroblasts. The gene discussed is NPAS2; the disease is rheumatoid arthritis.