Besides, synovial fluid contained significantly increased levels of matrix metalloproteinases (MMP3, MMP8, and MMP9), and cartilage-specific proteins, including cartilage oligomeric matrix protein, cartilage acidic protein 1, and aggrecan core protein compared to plasma samples from RA or HC (Figure 2C). The gene discussed is CRTAC1; the disease is rheumatoid arthritis.