IFIH1 and Aicardi-Goutieres syndrome: Consistent with a central role for interferon in the disease, AGS has been associated with heterozygous gain-of-function mutations in the dsRNA sensor Interferon Induced With Helicase C Domain 1 IFIH1 (MDA5), which increase its affinity for RNA as well as baseline and ligand-induced interferon signalling [4].