Definition:

STING (stimulator of interferon genes)-associated basculopathy with onset in infancy (SAVI) is a rare hereditary autoinflammatory disorder caused by gain-of-function mutations in TMEM173, the gene encoding the STING protein. It is considered that the mutations in the TMEM173 gene confer constitutive activation of STING and hypersensitivity to ligand stimulation, resulting in chronic activation of the STING-interferon pathway. Patients with SAVI have severe neonatal-onset small vessel vasculitis, which is expressed by telangiectatic ulcerative rashes in the limbs, earlobes, or nose, leading to microangiopathic thrombosis, vessel occlusion, and even risk of gangrene. Some SAVI patients may present chronic interstitial lung disease, which can be severe and lethal.