Three-prime repair exonuclease 1 (TREX1) plays a very important role in preventing the immune response by degrading cytosolic DNA fragments.TREX1 mutations have been observed in both SLE and AGS patients, and cGAS is required for triggering the autoimmune response by inducing type I IFNs in these contexts [103–105] . The gene discussed is TREX1; the disease is Aicardi-Goutieres syndrome.