PRTN3 and rheumatoid arthritis: Importantly, many prospective studies of pre-RA have utilized individuals who have initially presented to health-care with arthralgia and were subsequently found to have autoantibody positivity (14, 16); while the Healthfair cohort studied herein still had a substantial portion of individuals with some joint symptoms at baseline and therefore may be somewhat comparable to individuals identified through clinics, ~30% of ACPA(+) individuals who later developed RA did not report joint pain at baseline.