Five of these 16 genes were validated by a reported association of rheumatoid arthritis with SNPs within 200 kb of the transcription site, eight by association of the measured protein level with rheumatoid arthritis in UK Biobank, 10 by experimental perturbation in mouse models of inflammatory arthritis, and two—CTLA4 and PDCD1—by evidence that drugs targeting the gene cause or ameliorate inflammatory arthritis in humans. This evidence concerns the gene PDCD1 and rheumatoid arthritis.