In AGS patients, most of the mutations in the ADAR1 gene fall in the catalytic domain, and all the homozygous Adar mutations, e.g., the three mutations coding Adar K999N, W1112F, and Adar D1113H, are only found in the catalytic domain [1, 10]. The gene discussed is ADAR; the disease is Aicardi-Goutieres syndrome.