Recurrent acute necrotizing encephalopathy in a boy with RANBP2 mutation and thermolabile CPT2 variant: The first case of ANE1 in Japan

Clinical and genetic characteristics of RANBP2 mutations in children with acute necrotizing encephalopathy

BACKGROUND

This study investigated RANBP2 mutations in children with acute necrotizing encephalopathy (ANE) and conducted a systematic review of the differences in clinical characteristics between with or without RANBP2 mutations.

METHODS

Whole-exome sequencing was performed on 19 pediatric ANE patients at Beijing Children's Hospital affiliated to Capital Medical University between 2017 and 2020. A systematic literature review was also conducted on the clinical characteristics and spectrum analysis of RANBP2 mutations.

RESULTS

Besides the common mutation site c.1754 C > T, new mutation sites were identified, including c.7454G > T, c.7474 A > G, c.7807 C > T, c.7918 C > A, and c.872 A > G. These sites are highly conserved. Twenty-four publications describing 38 ANE children were reviewed, of which 22 cases had the RANBP2 mutations. When combined with our study, the data included 54 ANE children aged from 3 months to 120 months, and divided into RANBP2 mutation group (n = 26) and non-mutation group (n = 28). No significant differences were observed in initial presentations, neuroimaging, treatment, or outcomes between these two groups. However, children with RANBP2 mutations had slightly elevated blood ammonia levels and a broader etiological spectrum, especially involving non-influenza pathogens.

CONCLUSION

This study highlights novel RANBP2 mutation sites in ANE children and associates these mutations with higher blood ammonia levels and diverse etiologies.

Identification of Genetic Variants in Status Epilepticus Associated With Fever

PURPOSE

Status epilepticus associated with fever (SEF) is often encountered in pediatric emergency departments, and some patients develop neurological emergencies, such as acute encephalopathy (AE). Although numerous genetic variants of developmental and epileptic encephalopathy (DEE) have been reported, the frequency of these disease-associated variants of SEF is unknown. The first aim of this study was to investigate the associated genetic variants of SEF. The second aim was to compare the variations in genes between SEF and DEE.

METHOD

This retrospective, clinical observational study included patients with SEF or DEE who visited Kobe University Hospital or Kobe University affiliated hospitals and provided consent for a genetic diagnosis of SEF or DEE between January 1, 2021, and December 31, 2022.

FINDING

Fifteen patients with SEF and 27 patients with DEE consented to a genetic diagnosis and were included in the study. The detection rate of genetic variants was lower in patients with SEF (26.7%) than in those with DEE (63.0%), although there is no statistically significant difference (p = 0.05, Fisher's exact test). Analysis of patients with DEE revealed a wide variety of causative genes for DEE (16 different genes), whereas in SEF cases, only SCN1A variants were detected.

CONCLUSION

Our study is the first to clarify the detection rates of different genetic variants in SEF. Patients with SEF may have less genetic involvement in the onset of epileptic seizures, compared to those with DEE.

Acute necrotizing encephalopathy in an infant: A case report

Acute necrotizing encephalopathy is a rare, severe neurological condition, characterized by symmetrical necrotic brain lesions affecting the thalamus, cerebral white matter, brain stem, and cerebellum. Diagnosis relies on characteristic clinical and radiological features. We describe a 10-month-old female infant presenting with multiple seizures following a brief febrile upper respiratory illness. MRI of the brain showed bilateral symmetrical abnormal signal intensities involving both thalami and caudate nucleus, consistent with ANE. Management of ANE is symptom-related but high-dose steroids and IVIG have been used. This case highlights the importance of recognizing ANE beyond its usual geographic distribution. Early recognition and prompt management help improve outcomes.

Clinical prognostication in acute necrotizing encephalopathy of childhood: the role of magnetic resonance imaging severity assessment

BACKGROUND

Acute necrotizing encephalopathy of childhood is a unique entity with bilateral gray and white matter involvement.

OBJECTIVE

The aim of this study is to explore whether the severity of findings on imaging scans is indicative of the prognosis and clinical outcomes for pediatric patients with acute necrotizing encephalopathy.

MATERIALS AND METHODS

A retrospective cross-sectional study was conducted on 42 patients diagnosed with acute necrotizing encephalopathy. A severity score based on MR imaging was computed for each patient, utilizing a point system determined by the existence of factors such as hemorrhage, cavitation, enhancement, diffusion restriction, and lesion location. The scoring was categorized into mild, moderate, and severe. Clinical outcomes were determined at the time of discharge and at follow-ups as mild disability, moderate disability, severe disability, and death according to the modified Rankin Scale. Associations were determined by Fisher's exact test, chi-square test, and one-way ANOVA.

RESULTS

The study included 21 boys and 21 girls with a mean age of 71.5 months. A statistically significant connection (P=0.027) was found between the severity score from MR imaging and the clinical outcome. A statistically significant relationship was also observed between diffusion restriction (P=0.008), cerebellar involvement (P=0.048), and an unfavorable clinical outcome. Additionally, individuals who experienced shock exhibited a correlation with adverse outcomes (P=0.01).

CONCLUSION

In predicting the outcome of acute necrotizing encephalopathy, cerebellar involvement and presence of diffusion restriction were associated with worse clinical outcomes in our study. Developing a comprehensive MR-based severity score is crucial for improving diagnostic accuracy and patient outcomes. Our findings underscore the importance of including diffusion restriction and cerebellar involvement in the scoring system.

Viral entry and translation in brain endothelia provoke influenza-associated encephalopathy

Influenza-associated encephalopathy (IAE) is extremely acute in onset, with high lethality and morbidity within a few days, while the direct pathogenesis by influenza virus in this acute phase in the brain is largely unknown. Here we show that influenza virus enters into the cerebral endothelium and thereby induces IAE. Three-weeks-old young mice were inoculated with influenza A virus (IAV). Physical and neurological scores were recorded and temporal-spatial analyses of histopathology and viral studies were performed up to 72 h post inoculation. Histopathological examinations were also performed using IAE human autopsy brains. Viral infection, proliferation and pathogenesis were analyzed in cell lines of endothelium and astrocyte. The effects of anti-influenza viral drugs were tested in the cell lines and animal models. Upon intravenous inoculation of IAV in mice, the mice developed encephalopathy with brain edema and pathological lesions represented by micro bleeding and injured astrocytic process (clasmatodendrosis) within 72 h. Histologically, massive deposits of viral nucleoprotein were observed as early as 24 h post infection in the brain endothelial cells of mouse models and the IAE patients. IAV inoculated endothelial cell lines showed deposition of viral proteins and provoked cell death, while IAV scarcely amplified. Inhibition of viral transcription and translation suppressed the endothelial cell death and the lethality of mouse models. These data suggest that the onset of encephalopathy should be induced by cerebral endothelial infection with IAV. Thus, IAV entry into the endothelium, and transcription and/or translation of viral RNA, but not viral proliferation, should be the key pathogenesis of IAE.

Clinical characteristics and prognostic analysis of acute necrotizing encephalopathy of childhood: a retrospective study at a single center in China over 3 years

Objective

Acute Necrotizing Encephalopathy of Childhood (ANEC) is a rare, fulminant neurological disease in children with unknown mechanisms and etiology. This study summarized the clinical characteristics, treatment, and prognosis of ANEC through a retrospective analysis, providing insights into the ANEC early diagnosis and prognosis assessment.

Methods

Clinical data of children diagnosed with ANEC at the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University from July 1, 2020, to June 30, 2023, were retrospectively analyzed.

Results

There were 25 cases, 14 males and 11 females, with a median age of 3 years. Hospital admissions were mainly in the winter (14/25, 56%) and spring (9/25, 36%). All patients presented with varying degrees of fever and altered consciousness, with 92% (23/25) experiencing high body temperatures (>39.1°C) and 88% (22/25) having a Glasgow coma scale (GCS) score of ≤8. Seizures were observed in 88% (22/25) of patients. Laboratory findings indicated 100% B lymphocyte activation (14/14), and 78% (14/18) of patients showed cytokine storm (interleukin (IL)-6, IL-8, IL-10, interferon (IFN)-α). Neuroimaging showed symmetrical thalamus involvement, commonly involving basal ganglia and brainstem regions. Viral infection (23/24, 96%) was the predominant etiological finding, with 42% (10/24) of cases due to SARS-CoV-2 infection and 42% (10/24) to influenza A virus infection. Multi-organ dysfunction occurred in 68% (17/25) of patients, and 52% (13/25) died. Correlation analysis revealed the death group exhibited higher proportion of male, lower GCS scores, higher IL-6 level and a greater likelihood of associated brainstem impairment (p < 0.05).

Conclusion

ANEC is more prevalent in the winter and spring, and its etiology may be associated with B lymphocyte activation and cytokine storm following viral infections. Clinical manifestations lack specific features, with fever, consciousness disturbances, and seizures being the main presentations, particularly in cases of high fever and hyperpyrexia. ANEC progresses rapidly and has a high mortality rate. The child's gender, GCS score, IL-6 levels, and the presence of brainstem involvement can serve as important risk factors for assessing the risk of mortality.

Acute necrotizing encephalopathy associated with RANBP2 mutation: value of MRI findings for diagnosis and intervention

INTRODUCTION

Acute necrotizing encephalopathy (ANEC) is a rare entity characterized by encephalopathy following a febrile illness. Most patients are sporadic; however, recurrent and familial cases have been associated with RAN-binding protein 2 (RANBP2) mutation. Well-defined MRI findings can even be life-saving with early diagnosis and treatment.

METHODS

In this article, nine pediatric cases diagnosed with ANEC1 both clinically and radiologically, and with least one variation in the RANBP2 gene, are presented.

RESULTS

All patients were previously healthy and presented with encephalopathy after an acute febrile infection. The patients of 44% had a similar attack history in their family. Influenza A/B was detected in 7 patients (78%). One patient was admitted at age 32 years old. The first clinical findings of patients were encephalopathy (100%), seizure (44%), vision problems (33%), ataxia (11%), and monoplegia (11%). Recurrent attacks were seen in two (22%) patients. Brain MRI findings including bilateral thalamus, external capsules, and brainstem involvements were highly suggestive for RANBP2 mutation. Based on MRI findings, genetic analyses were quickly performed and confirmed. All of the patients were treated with empirical encephalitis treatment, oseltamivir, intravenous immunoglobulin (IVIG), high-dose steroid and, if necessary, plasmapheresis, but three (33%) patients died despite treatment.

CONCLUSION

ANEC associated with RANBP2 mutation may occur early or late-onset and can be recurrent and fatal. Therefore, early diagnosis and treatment have the potential to modify the severity of this encephalopathy. Well-defined MRI findings are highly instructive for early diagnosis.

Dravet syndrome and hemorrhagic shock and encephalopathy syndrome associated with an intronic deletion of SCN1A

OBJECTIVE

Hemorrhagic shock and encephalopathy syndrome (HSES) is a serious condition that requires intensive care and is associated with a high mortality rate. However, its pathogenesis remains unclear. In the present study, a genetic analysis was performed to determine the genetic background of patients with clinically suspected Dravet syndrome (DS) who developed HSES.

METHODS

Whole exome sequencing was performed, followed by minigene analysis of the intron variant detected by whole exome sequencing to confirm its effect on splicing.

RESULTS

Whole exome sequencing revealed a novel 21-bp deletion in intron 3 of SCN1A NM_001165963.4 (NC_000002.11:g.166073675_166073695del). This deletion was not found in the patient's parents and was proven to be de novo. Minigene analysis revealed an aberrant mRNA lacking 40 and 106 bp from the 5' end of exon 4 of SCN1A. Therefore, we diagnosed this case as DS due to the deletion in intron 3 of SCN1A.

CONCLUSIONS

We report a case of DS with HSES caused by a 21-bp deletion in the intron of SCN1A that was confirmed by minigene analysis. The present case met Levin's criteria for HSES and the splicing analysis of SCN1A is an important finding. This study has important implications for understanding HSES pathogenesis.

Genetic and environmental risk factors of acute infection-triggered encephalopathy

Acute encephalopathy is a constellation of syndromes in which immune response, metabolism and neuronal excitation are affected in a variable fashion. Most of the syndromes are complex disorders, caused or aggravated by multiple, genetic and environmental risk factors. Environmental factors include pathogenic microorganisms of the antecedent infection such as influenza virus, human herpesvirus-6 and enterohemorrhagic Escherichia coli, and drugs such as non-steroidal anti-inflammatory drugs, valproate and theophylline. Genetic factors include mutations such as rare variants of the SCN1A and RANBP2 genes, and polymorphisms such as thermolabile CPT2 variants and HLA genotypes. By altering immune response, metabolism or neuronal excitation, these factors complicate the pathologic process. On the other hand, some of them could provide promising targets to prevent or treat acute encephalopathy.

Infection and inflammation: radiological insights into patterns of pediatric immune-mediated CNS injury

The central nervous system (CNS) undergoes constant immune surveillance enabled via regionally specialized mechanisms. These include selectively permissive barriers and modifications to interlinked innate and adaptive immune systems that detect and remove an inciting trigger. The end-points of brain injury and edema from these triggers are varied but often follow recognizable patterns due to shared underlying immune drivers. Imaging provides insights to understanding these patterns that often arise from unique interplays of infection, inflammation and genetics. We review the current updates in our understanding of these intersections and through examples of cases from our practice, highlight that infection and inflammation follow diverse yet convergent mechanisms that can challenge the CNS in children.

Pathogenesis and Preventive Tactics of Immune-Mediated Non-Pulmonary COVID-19 in Children and Beyond

The COVID-19 pandemic has evolved to immune escape and threatened small children and the elderly with a higher severity and fatality of non-pulmonary diseases. These life-threatening non-pulmonary COVID-19 diseases such as acute necrotizing encephalopathies (ANE) and multisystem inflammatory syndrome in children (MIS-C) are more prevalent in children. However, the mortality of multisystem inflammatory syndrome in adults (MIS-A) is much higher than that of MIS-C although the incidence of MIS-A is lower. Clarification of immunopathogenesis and genetic susceptibility of inflammatory non-pulmonary COVID-19 diseases would provide an appropriate guide for the crisis management and prevention of morbidity and fatality in the ongoing pandemic. This review article described three inflammatory non-pulmonary COVID-19 diseases including (1) meningoencephalitis (ME), (2) acute necrotizing encephalopathies (ANE), and (3) post-infectious multisystem inflammatory syndrome in children (MIS-C) and in adults (MIS-A). To prevent these life-threatening non-pulmonary COVID-19 diseases, hosts carrying susceptible genetic variants should receive prophylactic vaccines, avoid febrile respiratory tract infection, and institute immunomodulators and mitochondrial cocktails as early as possible.

Early therapeutic plasma exchange may lead to complete neurological recovery in moderate to severe influenza-associated acute necrotizing encephalopathy

BACKGROUND

Acute necrotizing encephalopathy (ANE) is a pediatric neurological disease, presumably caused by cytokine storms, with a poor prognosis. Immunomodulatory therapy, including therapeutic plasma exchange (TPE), could be an effective treatment.

CASES

Two patients with influenza-associated ANE were treated. The ANE severity scores were 3 and 8 in case 1 (a 3-y-old boy) and case 2 (a 7-y-old boy), respectively. In case 1, intravenous methylprednisolone and TPE were initiated at 8 and 16 h, respectively, after the onset of impaired consciousness. In case 2, multiple organ failure and septic shock persisted even after infusion of fluids and inotropic agents. Intravenous methylprednisolone and TPE were started at 5 and 9 h, respectively, after the onset of impaired consciousness, which improved the inotrope-refractory septic shock. Patient 1 and 2 achieved complete neurological recovery within 4 weeks and after 3 months, respectively. In both patients, cytokine levels were serially measured. There were increased serum interleukin (IL)-6 and IL-10 levels in both patients; patient 1 showed increased IL-6 levels in the initial cerebrospinal fluid sample. There was a post-treatment decrease in serum IL-6 levels in both cases.

DISCUSSION

Early intensive immunomodulatory therapy with TPE may improve neurological outcomes in pediatric influenza-associated ANE. Further studies are required to establish the efficacy of TPE for ANE.

Clinical features and imaging manifestations of acute necrotizing encephalopathy in children

PURPOSE

We summarized the clinical features of acute necrotizing encephalopathy (ANE) in children.

METHODS

Clinical data of 14 children with ANE at one center from January 2017 to January 2020 were retrospectively analyzed. ANE severity score (ANE-ss) was used to assess ANE severity, and the Glasgow Outcome Scale-Extended was used to assess functional outcomes.

RESULTS

Peak incidence was between 1 and 3 years of age (71%), and a large percentage of males were affected (79%). The main manifestations included fever (100%), seizure (86%), and impaired consciousness (100%). Seven patients (58%) developed status epilepticus. The etiology was identified in 10 patients (71%) and mainly included H1N1 (36%) and Epstein-Barr virus (29%).Complications included multiple organ failure (MOF), predominantly liver (36%), heart (21%) and kidney (7%) failure, gastrointestinal hemorrhage (21%), hypernatremia (7%), hematuria (7%), disseminated intravascular coagulation (7%), and shock (7%). Pleocytosis was observed in two patients, and increased cerebrospinal fluid protein was found in 11 patients. A missense mutation in RANBP2 (c.1754C>T: p.Thr585Met) was observed in one patient. Magnetic resonance imaging revealed increased T2 and T1 signal density in multifocal and symmetric brain lesions (bilateral thalami, 100%) in all patients during the acute phase. There were no deaths. Nine children retained neurological sequelae affecting movement, cognition, speech, vision, and/or seizure. Four children recovered almost completely. There was a significant correlation between risk classification and outcome by ANE-ss.

CONCLUSION

ANE is a group of clinical and imaging syndromes. Most patients have severe neurological sequelae, and ANE may have lower mortality. And ANE-ss can assess prognosis.

Roles of Nucleoporin RanBP2/Nup358 in Acute Necrotizing Encephalopathy Type 1 (ANE1) and Viral Infection

Ran Binding Protein 2 (RanBP2 or Nucleoporin358) is one of the main components of the cytoplasmic filaments of the nuclear pore complex. Mutations in the RANBP2 gene are associated with acute necrotizing encephalopathy type 1 (ANE1), a rare condition where patients experience a sharp rise in cytokine production in response to viral infection and undergo hyperinflammation, seizures, coma, and a high rate of mortality. Despite this, it remains unclear howRanBP2 and its ANE1-associated mutations contribute to pathology. Mounting evidence has shown that RanBP2 interacts with distinct viruses to regulate viral infection. In addition, RanBP2 may regulate innate immune response pathways. This review summarizes recent advances in our understanding of how mutations in RANBP2 contribute to ANE1 and discusses how RanBP2 interacts with distinct viruses and affects viral infection. Recent findings indicate that RanBP2 might be an important therapeutic target, not only in the suppression of ANE1-driven cytokine storms, but also to combat hyperinflammation in response to viral infections.

Clinical evaluation of acute necrotizing encephalopathy in children

OBJECTIVE

Acute necrotizing encephalopathy (ANE) is a rare but severe encephalopathy and is associated with a high morbidity and mortality. We aimed to analyze and compare the clinical features and predictive indicators of pediatric ANE.

MATERIALS AND METHODS

This retrospective study included children with ANE diagnosed at Guangzhou Women and Children's Medical Center between November 2018 and January 2020. Pediatric patients' information, including clinical characteristics, laboratory tests, neuroelectrophysiology and brain magnetic resonance imaging (MRI) findings, MRI score, brainstem auditory evoked potential (BAEP) grades, ANE severity scores (ANE-SS), and modified Rankin scale (mRS), were collected.

RESULTS

Twelve ANE patients were included. Among them, one patient (8.3%) died from brainstem dysfunction, one (8.3%) recovered and 10 (83.3%) experienced neurological sequelae. All patients had an initial viral infection and neurological symptoms such as acute disturbance of consciousness (ADOC) or seizure, and the interval from onset of the disease to neurological manifestations was 3 (1.25-3) days. MRI score-I ranged from 1 to 3 (1.8 ± 0.7), MRI score-II ranged from 1 to 4 (2.5 ± 1.1). ANE-SS varied from 1 to 6 (3.9 ± 1.3). The scores of mRS were from 0 to 6 (2.9 ± 1.7). Higher MRI score were associated with worse outcomes, while the BAEP grade and ANE-SS score were not significantly associated with mRS.

CONCLUSION

ANE is a severe encephalopathy syndrome with rapid progression, resulting in serious neurological sequelae. Compared with BAEP grade and ANE-SS, brain MRI shows more comprehensive advantages in predicting the prognosis of ANE patients. More in-depth research and better indicators are still needed to support the evaluation and treatment of ANE.