Baricitinib Treatment in RNU7‐1‐Associated Aicardi–Goutières Syndrome in a South African Child: A Case Report

ABSTRACT Aicardi–Goutières syndrome (AGS) is a rare monogenic type I interferonopathy. Janus kinase (JAK) inhibition has emerged as a potential treatment for AGS. RNU7‐1 is one of the most recently discovered genes for AGS, and the clinical effects of JAK inhibition in these patients have not been reported. Here, we describe the diagnosis and treatment of a South African infant with RNU7‐1 ‐related AGS. The patient presented with developmental delay at age 5 months and was diagnosed with cerebral palsy due to a suspected congenital infection. By 18 months of age, he had a vasculitic rash, prominent generalized dystonia, persistent transaminitis, recurrent stomatitis, moderate‐range global developmental delay, and difficulty sleeping. AGS was considered after finding neuroimaging features of the disease; the diagnosis was confirmed when genetic investigations revealed two likely pathogenic RNU7‐1 compound heterozygous variants in the patient. Elevated interferon gene expression was noted in the patient and his mother who was a carrier of one RNU7‐1 variant. Baricitinib treatment was started, leading to modest, transient improvements in some clinical manifestations and a reduction in interferon‐stimulated gene expression. Liver function, dystonia, and neurological function did not improve even after increasing the baricitinib dose. Baricitinib was discontinued due to persistent and worsening adverse effects.