Heterozygous germline mutations in TNFAIP3 cause a Behçet's‐like disease, characterized by early‐onset systemic inflammation, arthralgia/arthritis, oral/genital ulcers, and ocular inflammation described in six unrelated families.154TNFAIP3 encodes the NF‐κB regulatory protein A20 which is a potent inhibitor of the NF‐κB signaling pathway via its deubiquitinase activity. The gene discussed is TNFAIP3; the disease is Arthritis.