Following stratification for ACPA status, a similar association pattern was also observed in both ACPA-positive (P = 0.021, Kruskal–Wallis) and ACPA-negative RA (P = 0.14, Kruskal–Wallis), though the latter did not reach the statistic significance due to the loss of power in the analysis. This evidence concerns the gene PRTN3 and rheumatoid arthritis.