A heterozygous c.2159G>A (p.Arg720Gln) mutation in the IFIH1 gene (NM_022168.4) has been previously identified in six individuals with a severe AGS phenotype and its functional effect has been demonstrated by IFN scoring (2, 5, 17, 18). This evidence concerns the gene IFNA1 and Aicardi-Goutieres syndrome.