First Egyptian patient with STING-associated vasculopathy with onset in infancy

STING-associated vasculopathy with onset in infancy: a familial case series report and literature review

Stimulator of interferon genes (STING1) is a key intermediary in activating the type I IFN response. STING-associated vasculopathy with onset in infancy (SAVI) is a very rare autoinflammatory disease that is caused by heterozygous gain-of-function mutations in STING1. SAVI typically manifests as neonatal-onset systemic inflammation, interstitial lung disease (ILD), and severe cutaneous vasculopathy located in acral regions, including fingers, toes, ears, and nose. Severity of ILD and recurrent pulmonary infections are crucial for the prognosis. Therapeutic options for SAVI are quite limited, and JAK inhibitors are considered to be a promising treatment according to several recent case reports. We report on a familial case series of SAVI with the R281Q mutation in the STING1 gene with predominant ILD manifestations, absence of cutaneous lesions, and poor response to ruxolitinib. Moreover, we reviewed all the case reports of SAVI in English published in the PubMed database. The atypical phenotype of the current cases adds to the growing list of inflammatory syndromes associated with SAVI. The literature analysis suggests that the severity and natural courses of the disease seem to be independent of the mutation type. Although JAK inhibitors may be a promising treatment, the therapeutic effect for different phenotypes and disease statuses of SAVI warrants further investigation.

Overview of STING-Associated Vasculopathy with Onset in Infancy (SAVI) Among 21 Patients

BACKGROUND

Gain-of-function mutations in STING1 underlie a type I interferonopathy termed SAVI (STING-associated vasculopathy with onset in infancy). This severe disease is variably characterized by early-onset systemic inflammation, skin vasculopathy, and interstitial lung disease (ILD).

OBJECTIVE

To describe a cohort of patients with SAVI.

METHODS

Assessment of clinical, radiological and immunological data from 21 patients (17 families) was carried out.

RESULTS

Patients carried heterozygous substitutions in STING1 previously described in SAVI, mainly the p.V155M. Most were symptomatic from infancy, but late onset in adulthood occurred in 1 patient. Systemic inflammation, skin vasculopathy, and ILD were observed in 19, 18, and 21 patients, respectively. Extensive tissue loss occurred in 4 patients. Severity of ILD was highly variable with insidious progression up to end-stage respiratory failure reached at teenage in 6 patients. Lung imaging revealed early fibrotic lesions. Failure to thrive was almost constant, with severe growth failure seen in 4 patients. Seven patients presented polyarthritis, and the phenotype in 1 infant mimicked a combined immunodeficiency. Extended features reminiscent of other interferonopathies were also found, including intracranial calcification, glaucoma and glomerular nephropathy. Increased expression of interferon-stimulated genes and interferon α protein was constant. Autoantibodies were frequently found, in particular rheumatoid factor. Most patients presented with a T-cell defect, with low counts of memory CD8+ cells and impaired T-cell proliferation in response to antigens. Long-term follow-up described in 8 children confirmed the clinical benefit of ruxolitinib in SAVI where the treatment was started early in the disease course, underlying the need for early diagnosis. Tolerance was reasonably good.

CONCLUSION

The largest worldwide cohort of SAVI patients yet described, illustrates the core features of the disease and extends the clinical and immunological phenotype to include overlap with other monogenic interferonopathies.

Stimulator of Interferon Genes-Associated Vasculopathy With Onset in Infancy: A Systematic Review of Case Reports

Objective: To summarize and analyze the manifestations of stimulator of interferon genes (STING)-associated vasculopathy with onset in infancy (SAVI). Methods: A systematic literature review was performed including cases from January 1, 2014, to February 1, 2020, using PubMed, OVID, CNKI, and WanFang. This included all the literature containing comparatively complete clinical data. Statistical analysis was performed using SPSS 20.0 to analyze the difference in age of onset, severity of skin lesions, and respiratory symptoms between SAVI patients with p.N154S and p.V155M mutations. Results: A total of 25 papers were included reporting on 51 individuals, of whom 17 had familiar inheritance of their mutation. Patients included 27 males and 24 females, and 8 fatal cases were observed. A total of 10 mutation sites have been reported in the STING gene, with p.V155M being the most prevalent. We identified SAVI as an early-onset disease with a median age of onset of 3 months after birth. Skin lesions were the most common symptoms of SAVI, found in 94.1% (48/51) of patients, while 76% (19/25) who had undergone a skin biopsy showed vasculopathy. Involvement of the lungs was identified in 68.6% (35/51) of patients, while only 22.2% (4/18) who had undergone a lung biopsy showed vasculopathy. Of 20 patients, 19 had increased immunoglobulin, mainly IgG. Furthermore, 45.1% (23/51) of patients had a positive low titer or were transiently positive for antinuclear antibodies. Of the 18 patients treated with JAK inhibitors, 6 relapsed and 2 died of acute respiratory failure caused by viral infection. Patients with p.N154S mutation had an earlier disease onset (p = 0.002) and more severe skin lesions (p < 0.001) than those patients with p.V155M mutation. Conclusion: SAVI is an early-onset disease accompanied by skin and lung lesions whose clinical presentation varies among patients with different genotypes. Therapeutic effects of JAK inhibitors are unsatisfactory.