As such, there is a limited understanding of how longitudinal changes of autoantibody positivity for ACPA and RF may further inform the likelihood and timing of incident clinical IA/RA, as well as potentially provide insights into how various ‘endotypes’ of RA may develop (e.g. ACPA and RF positive RA, versus ACPA positive alone). Here, PRTN3 is linked to rheumatoid arthritis.