IFIH1 and Encephalopathy: Hereditary mutations in ADAR, as well as in other genes such as TREX1, SAMHD1, RNASEH2, RNU7, LSM11, and IFIH1 (MDA5), have been linked to the development of the rare congenital inflammatory disorder Aicardi-Goutières syndrome (AGS), which clinically mimics encephalopathies caused by in utero-acquired virus infections (11, 14, 28, –, 33).