Moreover, the presence of local bone loss at the metacarpal site, detected with High Resolution peripheral Quantitative Computed Tomography (HRpQCT), was observed in RA patients with ACPA positivity, but not in ACPA-negative subjects or in other seronegative inflammatory arthritides such as psoriatic arthritis (PsA) (16). The gene discussed is PRTN3; the disease is rheumatoid arthritis.