Well described examples of IEI with associated somatic mutations can be found in adult patients with autoinflammatory disorders such as cryopyrin-associated periodic syndrome (CAPS due to gain of function (GOF) mutation in NLRP3), VEXAS (Vacuoles, E1 enzyme, X linked, Autoinflammatory, Somatic, due to hypomorphic mutations in UBA1) syndrome and A20 haploinsufficiency (LOF mutations in TNFAIP3). The gene discussed is TNFAIP3; the disease is cryopyrin-associated periodic syndrome.