This letter, published in the Journal of Clinical Immunology, discusses COPA syndrome, a rare genetic disease characterized by chronic activation of the innate immune system. The authors report a case of a 2-year-old girl with COPA syndrome who developed bronchodysplasia and diffuse interstitial lung disease. They identified a novel pathogenic mutation in the COPA gene and conducted in vitro experiments to confirm its pathogenicity. The authors suggest that the early neonatal onset of symptoms in this case contributes to the observed variation in clinical penetrance of COPA syndrome. [Extracted from the article]