A HIP1 SNP regulates arthritis severity in pristane-induced arthritis in rats, and knockdown of HIP1 reduced the invasive properties of FLS from arthritic rats and patients with RA, which is a clinically relevant in vitro phenotype that strongly correlates with histological and radiographic damage in rodent models of arthritis (12) and in RA (19). The gene discussed is HIP1; the disease is arthritic joint disease.