AGS is caused by mutations in genes that are involved in nucleic acid metabolism or sensing, including loss-of-function mutations in TREX1, SAMHD1, RNASEH2A-C, and ADAR1 and gain-of-function mutations in IFIH1, which encodes the double-stranded RNA (dsRNA) sensor MDA5 (3–7). This evidence concerns the gene ADAR and Aicardi-Goutieres syndrome.