ADAR and Aicardi-Goutieres syndrome: Whole-exome sequencing of AGS patients revealed that the mutation of Asp1113 in the ADAR1 deaminase region to histidine reduces the RNA editing activity of ADAR1, and a large amount of unedited dsRNA accumulates in cells and then activates MDA5, leading to MDA5-dependent symptoms of AGS encephalopathy such as astrocytosis and microgliosis (80, 81).