What are the genetic changes related to Aicardi-Goutieres syndrome ?
Mutations in the TREX1, RNASEH2A, RNASEH2B, RNASEH2C, and SAMHD1 genes have been identified in people with Aicardi-Goutieres syndrome.  The TREX1, RNASEH2A, RNASEH2B, and RNASEH2C genes provide instructions for making nucleases, which are enzymes that help break up molecules of DNA and its chemical cousin RNA. Mutations in any of these genes are believed to result in an absent or dysfunctional nuclease enzyme. Researchers suggest that absent or impaired enzyme function may result in the accumulation of unneeded DNA and RNA in cells. These DNA and RNA molecules or fragments may be generated during the first stage of protein production (transcription), copying (replication) of cells' genetic material in preparation for cell division, DNA repair, cell death, and other processes. The unneeded DNA and RNA may be mistaken by cells for that of viral invaders, triggering immune system reactions that result in encephalopathy, skin lesions, and other signs and symptoms of Aicardi-Goutieres syndrome.  The SAMHD1 gene provides instructions for making a protein whose function is not well understood; however, it is believed to be involved in the immune system and the inflammatory process. Mutations in this gene likely result in a protein that does not function properly, resulting in immune system abnormalities, inflammatory damage to the brain and skin, and other characteristics of Aicardi-Goutieres syndrome.