In 2016, we published a study based on a cohort of 155 treatment-naïve patients with early RA, which first demonstrated an independent correlation between ACPA-positivity and reduced densitometric values in patients with early RA [13], thus providing additional support to the osteoclastogenic effects of ACPAs that were previously observed in vitro and in animal models. The gene discussed is PRTN3; the disease is rheumatoid arthritis.