Analysis of clinical characteristics of children with Aicardi-Goutieres syndrome in China

[Aicardi-Goutieres syndrome type 6 associated with a compound heterozygous variant in ADAR: a first case report in the Russian population]

Aicardi-Goutieres syndrome (AGS) is a rare hereditary disorder with different types of inheritance manifested by progressive leukoencephalopathy with early onset, sharing common features with autoimmune disease. This article describes the first Russian case of AGS type 6 (AGS6) associated with compound heterozygote c.577C>G (p.Pro193Ala)+c.2304G>A (p.Trp768*) in ADAR and provides a more in-depth understanding of AGS6 by summarizing the worldwide literature and suggesting models for practitioners to diagnose patients with clinically suspected AGS.

Children With Type I Interferonopathy: Commonalities and Diversities in a Large Patient Cohort

OBJECTIVE

This study aimed to provide a comprehensive overview of the clinical features, laboratory and screening results, treatment options, and outcomes of patients with type I interferonopathy. Our secondary goal was to identify the predictors of long-term morbidity or mortality.

METHODS

We included children with genetically confirmed type I interferonopathies, with a follow-up duration of > 1 year. Data were obtained retrospectively from medical records.

RESULTS

Of the 40 eligible patients for the study, 52.5% were female, with a median age of disease onset of 1.5 years (range 0.1-13.2 yrs). They were diagnosed at an average age of 6.8 (SD 4.6) years. Aicardi-Goutières syndrome was the most common diagnosis (n = 15, 37.5%). The central nervous system was the most frequently affected system (n = 27, 67.5%). Janus kinase inhibitors were administered to 17 (42.5%) patients. Twenty-five patients (62.5%) developed at least 1 permanent morbidity or died during follow-up; thus, they were included in the poor outcome group. Although younger age at disease onset, intracranial calcification (ICC), and lack of chilblains and elevated acute-phase reactants were significant in univariate logistic regression analysis, only ICC on magnetic resonance imaging at admission (adjusted odds ratio 19.69, 95% CI 1.08-359.05, P = 0.04) was found to be a significant predictor of poor outcomes in multivariate logistic regression analysis.

CONCLUSION

For the first time, we evaluated the predictors of poor outcomes in patients with type I interferonopathy with a broad spectrum of subtypes. Further, our study's unique patient characteristics can provide valuable insights into these extremely rare conditions.

LASSO-derived nomogram for early identification of pediatric monogenic lupus

BACKGROUND

Monogenic lupus is defined as systemic lupus erythematosus (SLE)/SLE-like patients with either dominantly or recessively inherited pathogenic variants in a single gene with high penetrance. However, because the clinical phenotype of monogenic SLE is extensive and overlaps with that of classical SLE, it causes a delay in diagnosis and treatment. Currently, there is a lack of early identification models for clinical practitioners to provide early clues for recognition. Our goal was to create a clinical model for the early identification of pediatric monogenic lupus, thereby facilitating early and precise diagnosis and treatment for patients.

METHODS

This retrospective cohort study consisted of 41 cases of monogenic lupus treated at the Department of Pediatrics at Peking Union Medical College Hospital from June 2012 to December 2022. The control group consisted of classical SLE patients recruited at a 1:2 ratio. Patients were randomly divided into a training group and a validation group at a 7:3 ratio. A logistic regression model was established based on the least absolute shrinkage and selection operator to generate the coefficient plot. The predictive ability of the model was evaluated using receiver operator characteristic curves and the area under the curve (AUC) index.

RESULTS

A total of 41 cases of monogenic lupus patients and 82 cases of classical SLE patients were included. Among the monogenic lupus cases (with a male-to-female ratio of 1:1.05 and ages of onset ranging from birth to 15 years), a total of 18 gene mutations were identified. The variables included in the coefficient plot were age of onset, recurrent infections, intracranial calcifications, growth and developmental delay, abnormal muscle tone, lymphadenopathy/hepatosplenomegaly, and chilblain-like skin rash. Our model demonstrated satisfactory diagnostic performance through internal validation, with an AUC value of 0.97 (95% confidence interval = 0.92-0.97).

CONCLUSIONS

We summarized and analyzed the clinical characteristics of pediatric monogenic lupus and developed a predictive model for early identification by clinicians. Clinicians should exercise high vigilance for monogenic lupus when the score exceeds - 9.032299.

The prototypical interferonopathy: Aicardi-Goutières syndrome from bedside to bench

Aicardi-Goutières syndrome (AGS) is a progressive genetic encephalopathy caused by pathogenic mutations in genes controlling cellular anti-viral responses and nucleic acid metabolism. The mutations initiate autoinflammatory processes in the brain and systemically that are triggered by chronic overproduction of type I interferon (IFN), including IFN-alpha. Emerging disease-directed therapies aim to dampen autoinflammation and block cellular responses to IFN production, creating an urgent and unmet need to understand better which cells, compartments, and mechanisms underlying disease pathogenesis. In this review, we highlight existing pre-clinical models of AGS and our current understanding of how causative genetic mutations promote disease in AGS, to promote new model development and a continued focus on improving and directing future therapies.

Novel insights into double-stranded RNA-mediated immunopathology

Recent progress in human and mouse genetics has transformed our understanding of the molecular mechanisms by which recognition of self double-stranded RNA (self-dsRNA) causes immunopathology. Novel mouse models recapitulate loss-of-function mutations in the RNA editing enzyme ADAR1 that are found in patients with Aicardi-Goutières syndrome (AGS) - a monogenic inflammatory disease associated with increased levels of type I interferon. Extensive analyses of the genotype-phenotype relationships in these mice have now firmly established a causal relationship between increased intracellular concentrations of endogenous immunostimulatory dsRNA and type I interferon-driven immunopathology. Activation of the dsRNA-specific immune sensor MDA5 perpetuates the overproduction of type I interferons, and chronic engagement of the interferon-inducible innate immune receptors PKR and ZBP1 by dsRNA drives immunopathology by activating an integrated stress response or by inducing excessive cell death. Biochemical and genetic data support a role for the p150 isoform of ADAR1 in the cytosol in suppressing the spontaneous, pathological response to self-dsRNA.

Tocilizumab reduces the unmanageable inflammatory reaction of a patient with Aicardi-Goutières syndrome type 7 during treatment with ruxolitinib

BACKGROUND

Aicardi-Goutières syndrome (AGS) is a rare hereditary early-onset encephalopathy characterized by upregulation of the type I interferon pathway, poorly responsive to conventional immunosuppression.

CASE PRESENTATION

We describe a 7-year-old Chinese boy who developed symptoms at the age of 6 months. He presented with a chilblain-like rash, leukopenia, neutropenia, elevated liver enzymesgrowth retardation, microcephaly, elevated acute phase reactants, intracranial calcification and leukodystrophy. At the age of 3 years old, whole-exome sequencing confirmed a de novo heterozygous gain-of-function mutation, c.1016 C > A (p.Ala339Asp), in the IFIH1 gene, and he was diagnosed with AGS7. He was treated with ruxolitinib accompanied by steroids and thalidomide for about four years. The rash, hematological manifestations, and the liver function were all improved, but the erythrocyte sedimentation rate remained consistently elevated until the addition of tocilizumab, a monoclonal antibody against interleukin 6.

CONCLUSIONS

Ruxolitinib was not successful in suppressing the inflammatory process, and tocilizumab produced highly encouraging results in reducing the inflammatory reaction of AGS. The study makes a significant contribution to the literature because we may found a potential alternative therapeutic option for AGS.

Aicardi-Goutières syndrome: A monogenic type I interferonopathy

Aicardi-Goutières syndrome (AGS) is a rare monogenic autoimmune disease that primarily affects the brains of children patients. Its main clinical features include encephalatrophy, basal ganglia calcification, leukoencephalopathy, lymphocytosis and increased interferon-α (IFN-α) levels in the patient's cerebrospinal fluid (CSF) and serum. AGS may be caused by mutations in any one of nine genes (TREX1, RNASEH2A, RNASEH2B, RNASEH2C, SAMHD1, ADAR1, IFIH1, LSM11 and RNU7-1) that result in accumulation of self-nucleic acids in the cytoplasm or aberrant sensing of self-nucleic acids. This triggers overproduction of type I interferons (IFNs) and subsequently causes AGS, the prototype of type I interferonopathies. This review describes the discovery history of AGS with various genotypes and provides the latest knowledge of clinical manifestations and causative genes of AGS. The relationship between AGS and type I interferonopathy and potential therapeutic methods for AGS are also discussed in this review.

Clinical spectrum and currently available treatment of type I interferonopathy Aicardi-Goutières syndrome

BACKGROUND

Aicardi-Goutières syndrome (AGS) is a genetically determined disorder with a variable phenotype. Since the original description of AGS, advances in gene sequencing techniques have resulted in a significant broadening of the phenotypic spectrum associated with AGS genes, and new clinical pictures have emerged beyond the classic presentation. The aim of this review is to provide a comprehensive analysis of the clinical spectrum of AGS and report currently available treatments and new immunosuppressive strategies.

DATA SOURCES

Literature reviews and original research articles were collected from databases, including PubMed and ClinicalTrials.gov. Relevant articles about AGS were included.

RESULTS

The involvement of the nervous system certainly represents the major cause of mortality and morbidity in AGS patients. However, other clinical manifestations, such as chilblains, hepatosplenomegaly, and hematological disturbances, may lead to the diagnosis and considerably impact the prognosis and overall quality of life of these patients. Therapeutic approaches of AGS are limited to interventions aimed at specific symptoms and the management of multiple comorbidities. However, advances in understanding the pathogenesis of AGS could open new and more effective therapies.

CONCLUSIONS

The over-activation of innate immunity due to upregulated interferon production plays a critical role in AGS, leading to multi-organ damage with the main involvement of the central nervous system. To date, there is no specific and effective treatment for AGS. New drugs specifically targeting the interferon pathway may bring new hope to AGS patients.

Type I Interferonopathies in Childhood

Type 1 interferonopathy is a novel context reflecting a group of inborn disorders sharing common pathway disturbances. This group of diseases is characterized by autoimmunity and autoinflammation caused by an upregulation of type 1 interferons (IFN)s due to certain genetic mutations. Several features are common in most of the diseases in this group, such as vasculitic skin changes, including chilblains, panniculitis, interstitial lung disease, basal ganglion calcifications, neuromotor impairments, epilepsy, stroke, and recurrent fever. Family history and consanguineous marriage are also common. IFN signature is a useful diagnostic tool and is positive in almost all patients with type 1 interferonopathies. Although IFN signature is a sensitive test, its specificity is relatively low. It can also be positive in viral infections and several connective tissue diseases. Therefore, next-generation sequence methods, whole exome sequencing (WES) in particular, are required for the ultimate diagnosis. The optimal treatment regime is still under debate due to a lack of clinical trials. Although high-dose steroids, anti-IL-1 and anti-IL-6 treatments, and reverse transcriptase inhibitors are used, JAK inhibitors are highly promising. Additionally, monoclonal antibodies against IFN-alpha and interferon-α receptor (IFNAR) are currently underway.