The absence of ANA in proband B.III.1 notwithstanding, the confluence of inflammatory arthritis, tumid/chillblain lupus rashes, neuroinflammatory lesions reminiscent of Aicardi-Goutieres Syndrome, peripheral blood mononuclear cell surface phenotype suggesting elevated serum IFN-I activity, and improvement with baricitinib (JAK1/JAK2 inhibitor) therapy all point toward an interferonopathy with autoimmune features. Here, BTG3 is linked to systemic lupus erythematosus.