In Aicardi-Goutières syndrome (AGS) and AGS animal models (4), dysregulated activation of the cGAS/STING pathway results from defects in the enzymes that degrade cytosolic DNA, such as the cytosolic exonuclease TREX1, leading to constitutive activation of IFN-stimulated genes (ISGs) and severe inflammation. The gene discussed is CGAS; the disease is Aicardi-Goutieres syndrome.