The erosive patients that did not develop RA were less often anticyclic citrullinated peptide antibody positive (P < 0.001), less often RF positive (P = 0.01), had a lower erythrocytic sedimentation rate (P = 0.004), a lower C-reactive protein (P = 0.005), a lower tender joint count (P < 0.001), a lower swollen joint count (P < 0.001) and experienced less severe morning stiffness as recorded on a visual analogue scale (P = 0.04) compared with the patients that progressed to RA. The gene discussed is CRP; the disease is rheumatoid arthritis.