A missense mutation in <i>IFIH1</i> encoding a cytoplasmic viral RNA sensor MDA5 has recently been identified in the SMS patients as well as in patients with a monogenic form of lupus.
In this study, we present a male child demonstrating recurrent febrile episodes, spasticity, and basal ganglia calcification suggestive of Aicardi-Goutières syndrome, who carries the same Arg822Gln mutation in IFIH1 previously associated with SMS.