RNASEH2A and Aicardi-Goutieres syndrome: Aicardi-Goutières Syndrome (AGS) is a genetically heterogenous disorder most commonly due to mutations in nucleases and related enzymes (e.g., TREX1, SAMDH1, RNASEH2A, 2B, and 2C) that degrade DNA, RNA, or DNA : RNA hybrids (38, 39).