IFIH1 and Aicardi-Goutieres syndrome: A subset of AGS patients with pathogenic variants in ADAR, SAMHD1, IFIH1, and RNASEH2B have been reported to exhibit a more variable phenotype, with later symptom onset, better preservation of motor and cognitive function, and partial or complete absence of classical neuroimaging features.3, 4, 5, 6, 7, 8, 9 Herein, we describe a patient whose relapsing clinical course further broadens the phenotype of AGS associated with pathogenic RNASEH2B variants.