Retinal vasculopathy in STING-associated vasculitis of infancy (SAVI)

Dear Editor, Stimulator of interferon genes (STING)-associated vasculopathy with onset in infancy (SAVI) is an autoinflammatory disease caused by autosomal dominant gain-of-function mutations in STING, encoding the stimulator of IFN genes protein [1, 2]. It is a rare type I interferonopathy that typically presents with neonatal-onset systemic inflammation, cutaneous vasculopathy, extensive tissue loss and interstitial lung disease. Here we describe two patients presenting with severe retinal vasculopathy, the first description of this phenotype in SAVI. Case 1, a 6-year-old boy, presented in early infancy with a persistent cough and tachypnoea with perihilar changes on chest X-ray, diffuse maculopapular rash, nail-clubbing and failure to thrive. He was referred for respiratory assessment at 7 months and found to have persistently abnormal acute phase reactants, an abnormal IFN gene signature and interstitial lung disease on CT chest. Genetic analysis by Sanger sequencing confirmed a heterozygous somatic mutation in STING (c. 463 G.A, p. V155M), confirming SAVI [3]. Treatment with corticosteroids and monthly-IVIG was ineffective. At age 29 months he was started on the Janus kinase inhibitor baricitinib (8 mg/day). This improved systemic inflammation and allowed weaning of glucocorticoids. His respiratory status remained stable. Age 5 years he presented with gradual visual loss in his left eye with perception of hand movements only; fundoscopy revealed retinal vessel telangiectasia, tortuosity and dilatation, with extensive intra- and subretinal exudates (Fig. 1A and B). This was managed conservatively and is under surveillance.