Aicardi–Goutières syndrome (AGS), a rare progressive encephalopathy caused by excessive upregulation of interferon (IFN) α activity, is the first identified type I interferonopathy; type I interferonopathies are a group of Mendelian autoimmune and autoinflammation disorders characterized by pathogenic polymorphisms that upregulate type I IFN signaling1. Here, IFNA1 is linked to Aicardi-Goutieres syndrome.