At 3 months of age, panel sequencing for hereditary autoimmune diseases was performed at the Kazusa DNA Research Institute, and seven of the nine genes—RNASEH2A, SAMHD1, RNASEH2B, RNASEH2C, TREX1, IFIH1, and ADAR—known to harbor mutations associated with AGS were analyzed. The gene discussed is RNASEH2B; the disease is Aicardi-Goutieres syndrome 1.