CGAS and Aicardi-Goutieres syndrome: In mouse models, mutations of genes responsible for AGS, such as RNase H2 (Pokatayev et al., 2016) and Trex1 (Gray et al., 2015), led to self-DNA-mediated activation of cGAS, a protein functionally and structurally similar to OASs (Hornung et al., 2014).