Interestingly, the genes found to be mutated in our patient material (such as SLAMF6 (ref. 38), PADI4 (ref. 39) and IRF1 (ref. 40)) have been shown to regulate autoimmunity and to be associated with the initiation and progression of RA (PADI4 and IRF1). Here, IRF1 is linked to rheumatoid arthritis.