Autoantibodies against citrullinated antigens (ACPA) are considered important in the development of the disease, even identified before the onset of RA; a recent study suggested a correlation between miR-146a and the presence of ACPA in patients with periodontal disease, an inflammatory condition within oral cavities, with evidence of local citrullination and therefore a possible inductor of autoantibody production [12]. The gene discussed is PRTN3; the disease is rheumatoid arthritis.