Aicardi-Goutières syndrome (AGS) is the prototypical cerebral interferonopathy and individuals with AGS have increased levels of the cytokine interferon (IFN)-α in the CSF (34–36), progressive encephalopathy with cerebral atrophy (35, 37), calcification in the basal ganglia and thalami (35, 37, 38), microangiopathy (38), diffuse white matter disease (35, 37, 38) and clinical signs such as irritability, ataxia, epileptic seizures and increased mortality (39). This evidence concerns the gene IFNA1 and cerebellar ataxia.