Identification of the genetic mutations underlying the ultrarare monogenic conditions STING-associated vasculopathy with onset in infancy (SAVI) and coatomer protein complex subunit alpha (COPA) syndrome revealed a role for the stimulator of interferon genes (STING) immune pathway in the pathogenesis of interstitial lung disease (ILD) in these conditions. The gene discussed is COPA; the disease is interstitial lung disease.