Genetic mutations associated with status epilepticus

Rates of Status Epilepticus and Sudden Unexplained Death in Epilepsy in People With Genetic Developmental and Epileptic Encephalopathies

BACKGROUND AND OBJECTIVES

The genetic developmental and epileptic encephalopathies (DEEs) comprise a large group of severe epilepsy syndromes, with a wide phenotypic spectrum. Currently, the rates of convulsive status epilepticus (CSE), nonconvulsive status epilepticus (NCSE), and sudden unexplained death in epilepsy (SUDEP) in these diseases are not well understood. We aimed to describe the proportions of patients with frequently observed genetic DEEs who developed CSE, NCSE, mortality, and SUDEP. Understanding the risks of these serious presentations in each genetic DEE will enable earlier diagnosis and appropriate management.

METHODS

In this retrospective analysis of patients with a genetic DEE, we estimated the proportions with CSE, NCSE, and SUDEP and the overall and SUDEP-specific mortality rates for each genetic diagnosis. We included patients with a pathogenic variant in the genes SCN1A, SCN2A, SCN8A, SYNGAP1, NEXMIF, CHD2, PCDH19, STXBP1, GRIN2A, KCNT1, and KCNQ2 and with Angelman syndrome (AS).

RESULTS

The cohort comprised 510 individuals with a genetic DEE, in whom we observed CSE in 47% and NCSE in 19%. The highest proportion of CSE occurred in patients with SCN1A-associated DEEs, including 181/203 (89%; 95% CI 84-93) patients with Dravet syndrome and 8/15 (53%; 95% CI 27-79) non-Dravet SCN1A-DEEs. CSE was also notable in patients with pathogenic variants in KCNT1 (6/10; 60%; 95% CI 26-88) and SCN2A (8/15; 53%; 95% CI 27-79). NCSE was common in patients with non-Dravet SCN1A-DEEs (8/15; 53%; 95% CI 27-79) and was notable in patients with CHD2-DEEs (6/14; 43%; 95% CI 18-71) and AS (6/19; 32%; 95% CI 13-57). There were 42/510 (8%) deaths among the cohort, producing a mortality rate of 6.1 per 1,000 person-years (95% CI 4.4-8.3). Cases of SUDEP accounted for 19/42 (48%) deaths. Four genes were associated with SUDEP: SCN1A, SCN2A, SCN8A, and STXBP1. The estimated SUDEP rate was 2.8 per 1,000 person-years (95% CI 1.6-4.3).

DISCUSSION

We showed that proportions of patients with CSE, NCSE, and SUDEP differ for commonly encountered genetic DEEs. The estimates for each genetic DEE studied will inform early diagnosis and management of status epilepticus and SUDEP and inform disease-specific counseling for patients and families in this high-risk group of conditions.

Investigating the genetic contribution in febrile infection-related epilepsy syndrome and refractory status epilepticus

Introduction

Febrile infection-related epilepsy syndrome (FIRES) is a severe childhood epilepsy with refractory status epilepticus after a typically mild febrile infection. The etiology of FIRES is largely unknown, and outcomes in most individuals with FIRES are poor.

Methods

Here, we reviewed the current state-of-the art genetic testing strategies in individuals with FIRES. We performed a systematic computational analysis to identify individuals with FIRES and characterize the clinical landscape using the Electronic Medical Records (EMR). Among 25 individuals with a confirmed FIRES diagnosis over the last decade, we performed a comprehensive review of genetic testing and other diagnostic testing.

Results

Management included use of steroids and intravenous immunoglobulin (IVIG) in most individuals, with an increased use of immunomodulatory agents, including IVIG, plasma exchange (PLEX) and immunosuppressants such as cytokine inhibitors, and the ketogenic diet after 2014. Genetic testing was performed on a clinical basis in almost all individuals and was non-diagnostic in all patients. We compared FIRES with both status epilepticus (SE) and refractory status epilepticus (RSE) as a broader comparison cohort and identified genetic causes in 36% of patients with RSE. The difference in genetic signatures between FIRES and RSE suggest distinct underlying etiologies. In summary, despite the absence of any identifiable etiologies in FIRES, we performed an unbiased analysis of the clinical landscape, identifying a heterogeneous range of treatment strategies and characterized real-world clinical practice.

Discussion

FIRES remains one of the most enigmatic conditions in child neurology without any known etiologies to date despite significant efforts in the field, suggesting a clear need for further studies and novel diagnostic and treatment approaches.

2022 Overview of Metabolic Epilepsies

Understanding the genetic architecture of metabolic epilepsies is of paramount importance, both to current clinical practice and for the identification of further research directions. The main goals of our study were to identify the scope of metabolic epilepsies and to investigate their clinical presentation, diagnostic approaches and treatments. The International Classification of Inherited Metabolic Disorders and IEMbase were used as a basis for the identification and classification of metabolic epilepsies. Six hundred metabolic epilepsies have been identified, accounting for as much as 37% of all currently described inherited metabolic diseases (IMD). Epilepsy is a particularly common symptom in disorders of energy metabolism, congenital disorders of glycosylation, neurotransmitter disorders, disorders of the synaptic vesicle cycle and some other IMDs. Seizures in metabolic epilepsies may present variably, and most of these disorders are complex and multisystem. Abnormalities in routine laboratory tests and/or metabolic testing may be identified in 70% of all metabolic epilepsies, but in many cases they are non-specific. In total, 111 metabolic epilepsies (18% of all) have specific treatments that may significantly change health outcomes if diagnosed in time. Although metabolic epilepsies comprise an important and significant group of disorders, their real scope and frequency may have been underestimated.

Multidisciplinary Care of Patients with Inherited Metabolic Diseases and Epilepsy: Current Perspectives

More than 650 inherited metabolic diseases may present with epilepsy or seizures. These diseases are often multisystem, life-long and induce complex needs of patients and families. Multidisciplinary care involves all stages of disease management: diagnostics, specific or symptomatic, acute and chronic treatments, and integrated care that takes into account not only medical, but also manifold psychosocial, educational, vocational and other needs of patients and their caregivers. Care coordination is indispensable to ensure smooth transitions of care across life and disease stages, including management of emergencies, transition from pediatric to adult services and palliative care. Care pathways are highly diverse and have to find the right balance between highly specialized and locally provided services. While multidisciplinary teams consist of many professionals, a named supervising physician in a highly specialized healthcare setting and a care coordinator are highly important. As the greatest burden of care always falls onto the shoulders of patients and/or families, patient empowerment should be a part of every care pathway and include provision of required information, involvement into common decision-making, patient’s and family’s education, support for self-management, liaison with peer support groups and emotional/ psychological support. Due to the rarity and complexity of these diseases, sufficient expertise may not be available in a national healthcare system and cross-border services (virtual or physical) in the recently developed European Reference Networks should be ensured through the proper organization of referral systems in each EU and EEA country. Finally, digital technologies are particularly important in the provision of services for patients with rare diseases and can significantly increase the availability of highly specialized services and expertise.

Refractory and Super-refractory Status Epilepticus

Context

Refractory status epilepticus (RSE) and super-refractory status epilepticus (SRSE) are neurological emergencies with considerable mortality and morbidity. In this paper, we provide an overview of causes, evaluation, treatment, and consequences of RSE and SRSE, reflecting the lack of high-quality evidence to inform therapeutic approach.

Sources

This is a narrative review based on personal practice and experience. Nevertheless, we searched MEDLINE (using PubMed and OvidSP vendors) and Cochrane central register of controlled trials, using appropriate keywords to incorporate recent evidence.

Results

Refractory status epilepticus is commonly defined as an acute convulsive seizure that fails to respond to two or more anti-seizure medications including at least one nonbenzodiazepine drug. Super-refractory status epilepticus is a status epilepticus that continues for ≥24 hours despite anesthetic treatment, or recurs on an attempted wean of the anesthetic regimen. Both can occur in patients known to have epilepsy or de novo, with increasing recognition of autoimmune and genetic causes. Electroencephalography monitoring is essential to monitor treatment response in refractory/super-refractory status epilepticus, and to diagnose non-convulsive status epilepticus. The mainstay of treatment for these disorders includes anesthetic infusions, primarily midazolam, ketamine, and pentobarbital. Dietary, immunological, and surgical treatments are viable in selected patients. Management is challenging due to multiple acute complications and long-term adverse consequences.

Conclusions

We have provided a synopsis of best practices for diagnosis and management of refractory/superrefractory status epilepticus and highlighted the lack of sufficient high-quality evidence to drive decision making, ending with a brief foray into avenues for future research.

Absence of RNA-binding protein FXR2P prevents prolonged phase of kainate-induced seizures

Status epilepticus (SE) is a condition in which seizures are not self-terminating and thereby pose a serious threat to the patient's life. The molecular mechanisms underlying SE are likely heterogeneous and not well understood. Here, we reveal a role for the RNA-binding protein Fragile X-Related Protein 2 (FXR2P) in SE. Fxr2 KO mice display reduced sensitivity specifically to kainic acid-induced SE. Immunoprecipitation of FXR2P coupled to next-generation sequencing of associated mRNAs shows that FXR2P targets are enriched in genes that encode glutamatergic post-synaptic components. Of note, the FXR2P target transcriptome has a significant overlap with epilepsy and SE risk genes. In addition, Fxr2 KO mice fail to show sustained ERK1/2 phosphorylation induced by KA and present reduced burst activity in the hippocampus. Taken together, our findings show that the absence of FXR2P decreases the expression of glutamatergic proteins, and this decrease might prevent self-sustained seizures.

High genetic burden in 163 Chinese children with status epilepticus

PURPOSE

This study aimed to investigate the genetic aetiology in Chinese children diagnosed with status epilepticus (SE).

METHODS

Next-generation sequencing, copy number variation (CNV) analysis, and other genetic testing methods were conducted for children with SE lacking an identifiable non-genetic aetiology. Furthermore, the phenotype and molecular data of patients with SE were retrospectively analysed.

RESULTS

Among children with SE lacking an identifiable non-genetic aetiology, 73 out of 163 children (44.8 %) were found to have causative variants associated with SE including 66 monogenic mutations in 22 genes and 7 CNVs. Based on the American College of Medical Genetics and Genomics scoring system, the monogenic variants included 64 pathogenic/likely pathogenic and 2 uncertain significance variants. SCN1A gene mutations (n = 32) were the most common cause, followed by TSC2 (n = 5), CACNA1A (n = 5), SCN2A (n = 4), SCN9A (n = 2) and DEPDC5 (n = 2) gene mutations. Sixteen mutations were identified in single genes. Furthermore, 51 (77.3 %) monogenic mutations were de novo. Age at SE onset < 1 year (odds ratio [OR] = 2.70, 95 % confidence interval [CI]: 1.25-5.83, p = 0.012) and co-morbidity of intellectual disability (OR = 3.36, 95 %CI: 1.61-6.99, p = 0.001) were independently associated with pathogenic genetic variants.

CONCLUSION

This study identified genetic aetiology in 44.8 % of patients with SE, which indicates a high burden of genetic aetiology among children with SE in China. Our findings highlight the importance for genetic testing of children with SE that lacks an identifiable non-genetic aetiology.

Familial aggregation of status epilepticus in generalized and focal epilepsies

OBJECTIVE

To determine whether familial aggregation of status epilepticus (SE) occurs in a large cohort of familial common epilepsies.

METHODS

We used the Epilepsy Phenome/Genome Project dataset, which consisted of 2,197 participants in 1,043 family units with ≥2 members having a common generalized or nonacquired focal epilepsy (NAFE). We identified participants with a history of traditionally defined SE (TSE) (seizures ≥30 minutes) and operationally defined SE (OSE) (seizures ≥10 minutes) by chart review. We assessed familial aggregation of TSE and OSE using χ² analysis and generalized estimating equations (GEE).

RESULTS

One hundred fifty-five (7%) participants in 1,043 families had ≥1 episodes of TSE. Two hundred fifty (11%) had ≥1 episodes of OSE. In a χ² analysis, the number of family units with ≥2 members having TSE (odds ratio [OR] 4.79, 95% confidence interval [CI] 2.56-8.97) or OSE (OR 4.23, 95% CI 2.67-6.70) was greater than expected by chance. In GEE models adjusted for sex, broad epilepsy class (GE or NAFE), age at onset, and duration of epilepsy, TSE in a proband predicted TSE in a first-degree relative (OR 2.79, 95% CI 1.24-6.22), and OSE in a proband predicted OSE in a first-degree relative (OR 2.91, 95% CI 1.65-5.15). The results remained significant in models addressing epilepsy severity by incorporating the number of antiseizure medications used or epilepsy surgery.

CONCLUSIONS

TSE and OSE showed robust familial aggregation in a cohort of familial epilepsy independently of epilepsy severity or class, suggesting that genetic factors contribute to SE independently of the genetic cause of these epilepsies.

CLINICALTRIALSGOV IDENTIFIER

NCT00552045.

Status epilepticus - time is brain and treatment considerations

PURPOSE OF REVIEW

Status epilepticus is a neurological emergency associated with high morbidity and mortality. There is a lack of robust data to guide the management of this neurological emergency beyond the initial treatment. This review examines recent literature on treatment considerations including the choice of continuous anesthetics or adjunctive anticonvulsant, the cause of the status epilepticus, and use of nonpharmacologic therapies.

RECENT FINDINGS

Status epilepticus remains undertreated and mortality persists to be unchanged over the past 30 years. New anticonvulsant choices, such as levetiracetam and lacosamide have been explored as alternative emergent therapies. Anecdotal reports on the use of other generation anticonvulsants and nonpharmacologic therapies for the treatment of refractory and super-refractory status epilepticus have been described.Finally, recent evidence has examined etiology-guided management of status epilepticus in certain patient populations, such as immune-mediated, paraneoplastic or infectious encephalitis and anoxic brain injury.

SUMMARY

Randomized clinical trials are needed to determine the role for newer generation anticonvulsants and nonpharmacologic modalities for the treatment of epilepticus remains and evaluate the long-term outcomes associated with continuous anesthetics.

Translational Genomics in Neurocritical Care: a Review

Translational genomics represents a broad field of study that combines genome and transcriptome-wide studies in humans and model systems to refine our understanding of human biology and ultimately identify new ways to treat and prevent disease. The approaches to translational genomics can be broadly grouped into two methodologies, forward and reverse genomic translation. Traditional (forward) genomic translation begins with model systems and aims at using unbiased genetic associations in these models to derive insight into biological mechanisms that may also be relevant in human disease. Reverse genomic translation begins with observations made through human genomic studies and refines these observations through follow-up studies using model systems. The ultimate goal of these approaches is to clarify intervenable processes as targets for therapeutic development. In this review, we describe some of the approaches being taken to apply translational genomics to the study of diseases commonly encountered in the neurocritical care setting, including hemorrhagic and ischemic stroke, traumatic brain injury, subarachnoid hemorrhage, and status epilepticus, utilizing both forward and reverse genomic translational techniques. Further, we highlight approaches in the field that could be applied in neurocritical care to improve our ability to identify new treatment modalities as well as to provide important information to patients about risk and prognosis.

New-Onset Refractory Status Epilepticus in Children: Etiologies, Treatments, and Outcomes

OBJECTIVES

To elucidate etiologies, treatment, functional and neurocognitive outcomes of children with new-onset refractory status epilepticus.

DESIGN

A single-center retrospective study.

SETTING

A tertiary care children's hospital.

PATIENTS

All patients between 1 month and 21 years old admitted with new-onset refractory status epilepticus between January 2004 and July 2017.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Clinical presentation, laboratory data, imaging studies, and treatments were collected during hospitalization. Outcomes were assessed at hospital discharge and follow-up in the outpatient neurology clinic based on functional and neurocognitive outcomes as well as development of epilepsy. A total of 674 unique patients presented with status epilepticus of which 40 had new-onset refractory status epilepticus. Patients were classified into either refractory status epilepticus or super-refractory status epilepticus. The etiology of most children with new-onset refractory status epilepticus remained cryptogenic. The most common identified etiology was viral (20%). None of the patients had a contributory positive neuronal antibody test. Several treatments were tried including immunotherapy which was used in half of the patients. Five patients died (12.5%) during the acute phase of their disease, with four lost to follow-up. Twenty out of the remaining 31 patients (65%) developed epilepsy and 18 (58%) had persistent neurocognitive impairment. There was no statistical significant difference in various outcome measures and various etiologies, patients' characteristics, and treatments.

CONCLUSIONS

In this single-center cohort, more than half of the children with new-onset refractory status epilepticus did not have an identifiable etiology. Unlike adult patients, the presence of positive neuronal antibody syndrome was rare. There was no difference in outcome between those with or without an identifiable etiology. As expected, patients with super-refractory status epilepticus had worse functional and neurocognitive outcomes. More standardized diagnostic and treatment algorithms are needed along with prospective multicenter studies.

What is the role of next generation sequencing in status epilepticus?

Status epilepticus is a life-threatening medical condition which requires immediate diagnosis and treatment. In children, it may be a recurrent manifestation in the context of heterogeneous severe developmental genetic encephalopathies, as well as the first neurological manifestation. Mutations in several genes have been consistently associated with status epilepticus despite none of them can be considered as 'pure' Mendelian status epilepticus gene. Most genetic conditions featuring status epilepticus can be assigned to specific phenotypic subgroups, including cortical dysplasias, inborn errors of metabolism, mitochondrial diseases, or epileptic encephalopathies and childhood syndromes. Next generation sequencing (NGS) has increased the number of genes associated with, and improved the turnaround time for molecular diagnosis of, status epilepticus, allowing more timely and rationale management choices for specific conditions. Next generation sequencing might become part of the standard of care in the near future for a large subset of patients with status epilepticus, especially in early life. At present, trios whole exome sequencing, with a first analysis of point and copy number variants of an in silico panel containing 'status epilepticus' genes might represent best choice as it would allow a rapid screening. This article is part of the Special Issue "Proceedings of the 7th London-Innsbruck Colloquium on Status Epilepticus and Acute Seizures".

De novo Absence Status Epilepticus in a pediatric cohort: Electroclinical pattern in a multicenter Italian patients cohort

PURPOSE

Absence Status epilepticus (AS) is a form of Non Convulsive Status Epilepticus defined as a prolonged, generalized and non-convulsive seizure, with an altered content of consciousness. We aim to describe a group of healthy children, who presented recurrent and unprovoked de novo AS as the only manifestation of their epilepsy, with an excellent response to antiepileptic drugs.

METHOD

We retrospectively reviewed the electroclinical and genetic features of 13 pediatric patients, referring to our epilepsy centers from 2005 to 2019, on the following criteria: (1) regular psychomotor development, (2) one or more unprovoked AS as the only epileptic manifestation, (3) normal blood testing, (4) normal neuroimaging, (5) EEG recording, (6) available follow-up (1-14 years).

RESULTS

Patients are 7 females and 6 males, aged 7-22, with a mean age at AS onset of 9,3 years. All of them started an antiepileptic therapy, with an excellent response to Valproic Acid (VPA) or Ethosuximide (ETS). 5 patients did not start the therapy immediately after the first AS and they presented recurrent AS (from 2 to 4 episodes). 10 of them performed aCGH, karyotype, NGS panel or Whole Exome Sequencing.

CONCLUSIONS

We suggest that de novo AS may be a well-defined age-related and self-limited epilepsy syndrome, with a good prognosis and excellent response to therapy, but it comes with a high risk of relapsing if not adequately treated with antiepileptic drugs.

Mitochondrial diseases and status epilepticus

This narrative review focuses on the pathophysiology, diagnosis, and management of status epilepticus in the context of primary mitochondrial disease. Epilepsy is common in mitochondrial disease, reported in >20% of adult cases and 40%-60% of pediatric cohorts. Status epilepticus is less frequently reported and appears to be associated with particular subgroups of mitochondrial disorders, namely defects of the mitochondrial DNA and its maintenance, and disorders of mitochondrial translation and dynamics. Mechanisms underlying mitochondrial status epilepticus are incompletely understood, and may include bioenergetic failure, oxidative stress, immune dysfunction, and impaired mitochondrial dynamics. Treatments tried in mitochondrial status epilepticus include antiepileptic drugs, anesthetic agents, magnesium, high-dose steroids, immune globulins, vagus nerve stimulation, and surgical procedures, all with variable success. The outcome of mitochondrial status epilepticus is extremely poor, and effective therapeutic options have not been reported. Improved understanding of the mechanisms underpinning mitochondrial status epilepticus is needed in order to develop more effective treatments.

Hidden in plain sight: Non-convulsive status epilepticus-Recognition and management

Non-convulsive status epilepticus (NCSE) is an electroclinical state associated with an altered level of consciousness but lacking convulsive motor activity. It can present in a multitude of ways, but classification based on the clinical presentation and electroencephalographic appearances assists in determining prognosis and planning treatment. The aggressiveness of treatment should be based on the likely prognosis and the underlying cause of the NCSE.

The Clinical Characteristics and Prognostic Analysis of Status Epilepticus in Northeast China

OBJECTIVE

Status epilepticus (SE) is a neurological emergency that may cause severe neurological deficiency and even death. The aim of this study was to analyze the clinical characteristics and prognosis of SE in northeast China. Additionally, the etiology and classification are discussed.

MATERIALS AND METHODS

We retrospectively collected the clinical profiles of patients diagnosed with SE in the Epilepsy Center of Jilin University between January 2011 and May 2015. The causes and clinical courses were investigated. The individuals were followed up by visit or telephone, and the prognoses were analyzed.

RESULTS

A total of 223 patients with SE were enrolled, including 134 cases with non-refractory SE (NRSE) and 89 cases with refractory or super-refractory SE (RSE/SRSE). Fifteen patients died during hospitalization, yielding a mortality of 6.73%; 11 of them succumbed to multiple organ dysfunction syndrome (MODS). Statistical analysis showed significant differences in age, family history of epilepsy, and the incidence of non-convulsive SE (NCSE) between the NRSE group and RSE/SRSE group (p < 0.05). We found no significant differences in the causes of SE (central nervous system infection, autoimmune encephalitis, and epilepsy) between these 2 groups.

CONCLUSION

In northeast China, SE is associated with relatively lower mortality, and MODS is the major cause of death. Older age and NCSE are risk factors predicting potential progression to RSE. Central nervous system infection, autoimmune encephalitis, and epilepsy were common causes of SE, but there was no significant association between any of these causes and the occurrence of RSE.

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Zusammenfassung. Der Status epilepticus, vor allem der konvulsive tonisch-klonische (Grand mal) Status epilepticus, ist ein Notfall, der zu einer sofortigen Behandlung führen muss. Die frühe Behandlung ist effektiver als der spätere Beginn, ebenso wie der Einsatz standardisierter Therapieprotokolle. Nach der Gabe von Benzodiazepinen muss die Aufdosierung eines Antikonvulsivums (Levetiracetam, Valproat oder Phenytoin) erfolgen, um das Wiederauftreten von Anfällen zu verhindern. Beim refraktären Status epilepticus werden die Anästhetika Propofol oder Midazolam (oder Thiopental) vorzugsweise unter EEG-Ableitung mit einem Burst-Suppressions-Muster eingesetzt. Neben der raschen Therapie sollte die Diagnostik nach der Ursache des Status epilepticus nicht vergessen werden. Insbesondere bei Persistenz sollte immer auch die Überprüfung der Diagnose erfolgen, um das Vorliegen eines Pseudostatus nicht-epileptischer Anfälle nicht zu übersehen.

DisGeNET: a comprehensive platform integrating information on human disease-associated genes and variants

The information about the genetic basis of human diseases lies at the heart of precision medicine and drug discovery. However, to realize its full potential to support these goals, several problems, such as fragmentation, heterogeneity, availability and different conceptualization of the data must be overcome. To provide the community with a resource free of these hurdles, we have developed DisGeNET (http://www.disgenet.org), one of the largest available collections of genes and variants involved in human diseases. DisGeNET integrates data from expert curated repositories, GWAS catalogues, animal models and the scientific literature. DisGeNET data are homogeneously annotated with controlled vocabularies and community-driven ontologies. Additionally, several original metrics are provided to assist the prioritization of genotype-phenotype relationships. The information is accessible through a web interface, a Cytoscape App, an RDF SPARQL endpoint, scripts in several programming languages and an R package. DisGeNET is a versatile platform that can be used for different research purposes including the investigation of the molecular underpinnings of specific human diseases and their comorbidities, the analysis of the properties of disease genes, the generation of hypothesis on drug therapeutic action and drug adverse effects, the validation of computationally predicted disease genes and the evaluation of text-mining methods performance.