Article Text
Abstract
Background and aims Stimulator of interferon genes (STING)-associated vasculopathy with onset in infancy (SAVI) is firstly described in 2014 as a type I interferonopathy that resulting from heterozygous mutations of TMEM173. This gene encodes the STING adaptor protein, and mutations lead to a gain of function on STING and overproduction of interferon beta. SAVI is characterized by neonatal-onset systemic inflammation, a severe cutaneous vasculopathy and interstitial lung disease. JAK inhibitors are considered as an effective therapeutic strategy. We sought to describe two missed diagnosed patients with SAVI (P1 and P2) in order to draw attention to this illness.
Methods The clinical data were collected and Sanger sequencing of the gene TMEM173 was performed. An introspection of missed diagnosis and differential diagnosis was discussed.
Results The two boys shared similar manifestations including recurrent skin abscess in winter with skin lesions and recurrent respiratory tract infections since their births. It occurred to us neutrophil defects like CGD but NBT test and DHR123 were normal for both of them in 2011. Peroxidase staining was positive and no mutations in MYD88 (P1). Computed tomography of the chest revealed pulmonary fibrosis yet no relevant genes (including ABCA3, SFTPC) mutations were found. Joint pain was significant for P2 but Naproxen was ineffective. Treatments with antibiotics turned out little improvement and wouldn’t prevent the progression. Finally, both of them died of respiratory and circulatory failure in 2012 and 2016 respectively. Recently, genetic mutations (c.463 G>A and c.461 A>G) in exon5 of TMEM173 were discovered, confirming the diagnosis of SAVI.
Conclusions Owing to unfamiliarity with this disease, some cases would have been misdiagnosed or missed diagnosed. Thus, we propose that SAVI should be taken into consideration for children with chilblain skin lesions and pulmonary fibrosis after ruling out other related genes mutations.