The interferon-stimulated gene (ISG) score was analyzed.<h4>Results</h4>We report four patients with a novel <i>UNC93B1</i> c.1007G>A p.R336H variant, including three presenting with juvenile arthritis or rheumatoid arthritis, and one with a predominant phenotype of ITP. Here, STING1 is linked to autoimmune thrombocytopenic purpura.