Haploinsufficiency of A20 (HA20), associated with mutations in the TNFAIP3 gene, is an early-onset autoinflammatory syndrome often mimicking the clinical spectrum of Behçet's disease (BD), including recurrent oral and genital ulcers, polyarthritis, skin involvement, and gastrointestinal manifestations (29). The gene discussed is TNFAIP3; the disease is Genital ulcers.