PADI4 and rheumatoid arthritis: The somatic mutations identified by the immunogene panel in patients 1 and 2 (PADI4, PROM1, C5, IRF1, SLAMF6 and SEC14L3) were screened in 82 RA patients with targeted amplicon sequencing (coverage 4,000–79,000 × , sensitivity 0.5% (ref. 14)).