Aicardi–Goutières syndrome (AGS) is a genetically heterogeneous disorder originally defined as an early-onset progressive encephalopathy that is characterized by intracranial calcification, white matter abnormalities, cerebral atrophy, cerebrospinal fluid (CSF) lymphocytosis, and inappropriate induction of a type I interferon (IFN)-mediated immune response, belonging to the group of type I interferonopathies (1, 2). The gene discussed is IFNA1; the disease is Aicardi-Goutieres syndrome.