Initially, RF and ACPA were positive in 10/87 (11.5%) and 5/87 (5.7%) of individuals, respectively, and a joint ultrasound showed PD-active synovitis in 74/87 (85.1%), PD active proliferative tenosynovitis in 57/87 (65.5%), PD active pseudo-tenosynovitis in 53/87 (60.9%) and bone erosions in 5/87 (5.7%) individuals. Here, PRTN3 is linked to synovitis.