For example, mutations in genes encoding nucleases, such as TREX1 and RNase H2, which cause the prototype type I interferonopathy, Aicardi-Goutières syndrome (AGS), suggest the pathogenic role of the accumulation of self-nucleic acids, which results in systemic inflammation and autoimmunity by activating type I interferon responses. The gene discussed is TREX1; the disease is Aicardi-Goutieres syndrome.