We have previously shown that (1) serum 14-3-3η expression is not strongly correlated with standard clinical and serological measures, is detected in both early and established RA, with sensitivities of 60% to 82% and 78%, respectively, and (2) that 14-3-3η positivity adds incrementally to both RF and ACPA positivity for diagnostic sensitivity [8]. The gene discussed is PRTN3; the disease is rheumatoid arthritis.