The clinical outcome and neuroimaging of acute encephalopathy after status epilepticus in Dravet syndrome

Pharmacological management of prolonged seizures in Dravet syndrome including intravenous phenytoin

Dravet syndrome (DS) is an infantile onset developmental and epileptic encephalopathy. Sodium channel blockers are known to exacerbate seizures in this syndrome. Due to its high incidence, the management of prolonged seizures is crucial for DS patients. There is still ambiguity regarding the use of intravenous phenytoin for prolonged seizure in DS patients mainly due to the lack of data, raising concern about the safety of it use. We conducted a retrospective study (from January 2009 to January 2020) aiming to assess the management of prolonged seizures in DS with a focus on the use of intravenous phenytoin. Data were collected for patients admitted to our hospital for seizures lasting >5 min. Among 52 identified patients in our database, 23 experienced 59 prolonged seizures managed in our hospital. Only four seizures ceased without rescue medication. Notably, the use of intravenous phenytoin was not associated with discernible adverse effects and was effective in stopping status epilepticus in 71% of cases. This study suggests the safety and efficacy of intravenous phenytoin for prolonged seizure in DS. There is a need for broader investigations of emergency treatments for evidence-based recommendations for the emergency plan of each patient.

Underlying Disorders in Children With Infection-Related Acute Encephalopathy

BACKGROUND

Various factors contribute to the development of infection-related acute encephalopathy (AE) in children, such as infectious agents and chronic underlying disorders. We studied underlying disorders in children with AE to identify predisposing factors of AE.

METHODS

We investigated underlying disorders or past histories in patients with two types of AE from the database in the Tokai area of Japan between 2009 and 2022: 204 patients with AE with reduced subcortical diffusion (AED) and 137 with clinically mild encephalopathy with a reversible splenial lesion (MERS). We compared them with 89 patients with acute disseminated encephalomyelitis (ADEM) to clarify the specific disorders in the two AE types.

RESULTS

The prevalence of underlying disorders in AED (34%, 70 patients) was significantly higher than that in ADEM (12%, 11 patients) (P < 0.01). The prevalence of underlying disorders in MERS was 23% (32 patients). The underlying disorders included seizure disorders, premature birth, genetic/congenital disorders, and endocrine/renal diseases. In patients with seizure disorders in AED, five patients (18%) had Dravet syndrome and four (15%) had West syndrome, whereas none with MERS had these syndromes. Twenty-five (12%) of 204 patients with AED, three (2%) with MERS, and one (1%) with ADEM were preterm or low birth weight.

CONCLUSIONS

The high prevalence of seizure disorders suggests that seizure susceptibility is an important predisposing factor in AED. Premature birth also has an impact on the development of AED. Caution is required regarding the development of AE in patients with chronic seizure disorders or premature birth.

Cerebral hemiatrophy and hemiparesis following hemiclonic status epilepticus in Dravet syndrome

Dravet syndrome is currently considered as an developmental and epileptic encephalopathy and, recently, mandatory, alert, and exclusionary criteria have been proposed. Here, we describe three patients with Dravet syndrome with the typical early presentation including febrile and afebrile alternating hemiclonic seizures due to loss-of-function SCN1A variants. Subsequently, they developed episodes of febrile focal status epilepticus (SE) associated with hemiparesis and cerebral hemiatrophy with posterior focal seizures, as a consequence of Dravet syndrome. This sequence of events has been previously published in patients with Dravet syndrome and does not contradict the recent classification by the International League Against Epilepsy (ILAE). The ILAE guidance identifies "Focal neurological findings" as alert criteria and "MRI showing a causal focal lesion" as exclusionary criteria for making an initial diagnosis of Dravet syndrome at presentation. Our three patients would correspond to a severe phenotype, similar to the well-known presentation of generalized atrophy following prolonged status epilepticus. Common genetic findings in cases of diffuse and unilateral brain involvement may help explain these clinical presentations. Further genotype-phenotype studies may provide additional insights into this electroclinical behavior.

Increased prime edit rates in KCNQ2 and SCN1A via single nicking all-in-one plasmids

BACKGROUND

Prime editing (PE) is the most recent gene editing technology able to introduce targeted alterations to the genome, including single base pair changes, small insertions, and deletions. Several improvements to the PE machinery have been made in the past few years, and these have been tested in a range of model systems including immortalized cell lines, stem cells, and animal models. While double nicking RNA (dncRNA) PE systems PE3 and PE5 currently show the highest editing rates, they come with reduced accuracy as undesired indels or SNVs arise at edited loci. Here, we aimed to improve single ncRNA (sncRNA) systems PE2 and PE4max by generating novel all-in-one (pAIO) plasmids driven by an EF-1α promoter, which is especially suitable for human-induced pluripotent stem cell (hiPSC) models.

RESULTS

pAIO-EF1α-PE2 and pAIO-EF1α-PE4max were used to edit the voltage gated potassium channel gene KCNQ2 and voltage gated sodium channel gene SCN1A. Two clinically relevant mutations were corrected using pAIO-EF1α-PE2 including the homozygous truncating SCN1A R612* variant in HEK293T cells and the heterozygous gain-of-function KCNQ2 R201C variant in patient-derived hiPSC. We show that sncRNA PE yielded detectable editing rates in hiPSC ranging between 6.4% and 9.8%, which was further increased to 41% after a GFP-based fluorescence-activated cell sorting (FACS) cell sorting step. Furthermore, we show that selecting the high GFP expressing population improved editing efficiencies up to 3.2-fold compared to the low GFP expressing population, demonstrating that not only delivery but also the number of copies of the PE enzyme and/or pegRNA per cell are important for efficient editing. Edit rates were not improved when an additional silent protospacer-adjacent motif (PAM)-removing alteration was introduced in hiPSC at the target locus. Finally, there were no genome-wide off-target effects using pAIO-EF1α-PE2 and no off-target editing activity near the edit locus highlighting the accuracy of snc prime editors.

CONCLUSION

Taken together, our study shows an improved efficacy of EF-1α driven sncRNA pAIO-PE plasmids in hiPSC reaching high editing rates, especially after FACS sorting. Optimizing these sncRNA PE systems is of high value when considering future therapeutic in vivo use, where accuracy will be extremely important.

Precision or narrative medicine? Child neurology needs both!

Precision medicine aims to understand the mechanisms of diseases and to find treatments adapted to each individual or group of patients, on the basis of biological characteristics and environment. It uses new tools based on digital technologies. Narrative medicine was theorized, in the 2000s, as a reaction to the increasing technicality and the notion of a lack of human relations in care: It focuses on recognizing the essential place of the patient's experience of illness and life history in the diagnosis and management of diseases as well as in the training of caregivers. These two opposite currents are rarely considered together. In fact, they have in common the basic principle that each patient is unique, and both are often more closely intertwined than we think, especially in the field of child neurology. Five case histories and discussions presented here aim to demonstrate that combining the precision approach with the narrative approach can improve the diagnosis, treatment, classification, and understanding of neurological conditions, as well as enhance the dialog with families and make teaching more meaningful. Not only rare diseases but common problems, such as paroxysmal events, pain, epilepsy, intellectual disability, and autism spectrum disorder, are addressed from both perspectives.

Two Perspectives on Dravet Syndrome: Viewpoints from the Clinician and the Caregiver

Dravet syndrome (DS) is a severe genetic epilepsy characterized by early-life onset, seizures, and neurodevelopmental delays that have major impacts on affected children. DS is an incurable condition that requires a lifelong multidisciplinary approach involving both clinical and caregiver support. A better understanding of the multiple perspectives involved in the care of patients is necessary for supporting the diagnosis, management, and treatment of DS. Here we describe the personal experiences of a caregiver and a clinician facing the challenges of diagnosing and treating a patient throughout the three phases of DS. During the initial phase, the main goals include establishing an accurate diagnosis, coordination of care, and communication between clinicians and caregivers. After a diagnosis is established, frequent seizures and developmental delays are a major concern in the second phase, which is very taxing on children and their caregivers, so caregivers require support and resources to advocate for safe and effective care. Seizures may improve in the third phase, but developmental, communication, and behavioral symptoms persist as caregivers navigate the eventual transition from pediatric to adult care. Optimal care for patients is provided when clinicians are well educated on the syndrome and collaboration is established between members of the medical team and family.

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.

Complications of Influenza A or B Virus Infection in Individuals With SCN1A-Positive Dravet Syndrome

BACKGROUND AND OBJECTIVES

To determine the frequency and spectrum of complications of influenza infection in individuals with SCN1A-positive Dravet syndrome (SCN1A-DS).

METHODS

Individuals with SCN1A-DS were identified in neurologists' care at 2 hospitals in Melbourne, Australia, with additional searches of EEG databases, the Victorian PAEDS FluCan influenza database, and the University of Melbourne Epilepsy Genetics Research Program database. Medical records were searched and families questioned to identify individuals who had an influenza infection; reported infections were confirmed by pathology report. For these individuals, we obtained baseline clinical characteristics and clinical details of the influenza infection.

RESULTS

Twenty-one of 82 individuals (26%) had 24 documented influenza infections (17 influenza A and 7 influenza B) at age 0.5-25 years (median 4 years). All presented to hospital, 18/24 (75%) for status epilepticus or seizure exacerbations. Recovery was prompt in 18/24 (75%) infections, delayed but complete in 1/24 (4%) and incomplete in 5/24 (21%). One child died from influenza pneumonia, and long-term neurologic sequelae were seen with 4 infections. These individuals were poorly responsive after termination of status epilepticus. Brain imaging in 2 showed cerebral edema and 1 also having imaging features of laminar necrosis. All have ongoing neurologic deficits compared with their baseline, 1 having profound global impairment.

DISCUSSION

Our data show that patients with SCN1A-DS are highly susceptible to neurologic complications during and severe sequelae after influenza infection, including moderate to severe persistent neurologic impairments and death. Safe administration of the seasonal influenza vaccine should be prioritized for this population.

Phenotypic expansion of KCNH1-associated disorders to include isolated epilepsy and its associations with genotypes and molecular sub-regional locations

PURPOSE

Genotype-phenotypic correlation of KCNH1 variant remains elusive. This study aimed to expand the phenotypic spectrum of KCNH1 and explore the correlations between epilepsy and molecular sub-regional locations.

METHODS

We performed whole-exome sequencing in a cohort of 98 patients with familiar febrile seizure (FS) or epilepsy with unexplained etiologies. The damaging effects of variants were predicted by protein modeling and multiple in silico tools. All reported patients with KCNH1 pathogenic variants with detailed neurological phenotypes were analyzed to evaluate the genotype-phenotype correlation.

RESULTS

Two novel KCNH1 variants were identified in three cases, including two patients with FS with inherited variant (p.Ile113Thr) and one boy with epilepsy with de novo variant (p.Arg357Trp). Variant Ile113Thr was located within the eag domain, and variant p.Arg357Trp was located in transmembrane domain 4 of KCNH1, respectively. Two patients experienced refractory status epilepticus (SE), of which one patient died of acute encephalopathy induced by SE. Further analysis of 30 variants in 51 patients demonstrated that de novo variants were associated with epileptic encephalopathy, while mosaic/somatic or germline variants cause isolated epilepsy/FS. All hotspot variants associated with epileptic encephalopathy clustered in transmembrane domain (S4 and S6), while those with isolated epilepsy/seizures or TBS/ZLS without epilepsy were scattered in the KCNH1.

CONCLUSIONS

We found two novel missense variants of KCNH1 in three individuals with isolated FS/epilepsy. Variants in the KCNH1 cause a spectrum of epileptic disorders ranging from a benign form of genetic isolated epilepsy/FS to intractable form of epileptic encephalopathy. The genotypes and variant locations help explaining the phenotypic variation of patients with KCNH1 variant.

Genetics and gene therapy in Dravet syndrome

Dravet syndrome is a well-established electro-clinical condition first described in 1978. A main genetic cause was identified with the discovery of a loss-of-function SCN1A variant in 2001. Mechanisms underlying the phenotypic variations have subsequently been a main topic of research. Various genetic modifiers of clinical severities have been elucidated through many rigorous studies on genotype-phenotype correlations and the recent advances in next generation sequencing technology. Furthermore, a deeper understanding of the regulation of gene expression and remarkable progress on genome-editing technology using the CRISPR-Cas9 system provide significant opportunities to overcome hurdles of gene therapy, such as enhancing Na_V1.1 expression. This article reviews the current understanding of genetic pathology and the status of research toward the development of gene therapy for Dravet syndrome. This article is part of the Special Issue "Severe Infantile Epilepsies".

The effectiveness of intravenous benzodiazepine for status epilepticus in Dravet syndrome

PURPOSE

We aimed to evaluate choice and efficacy of intravenous antiepileptic drugs (AEDs) for status epilepticus (SE) in Dravet syndrome and to find predictable clinical features demonstrating the effectiveness of benzodiazepine (BZD) for SE.

METHODS

We retrospectively investigated the medical records in patients with Dravet syndrome and evaluated the effectiveness rate of intravenous AEDs and the rate of adverse effects. To find the clinical features of BZD-effective SE, we divided the SE episodes into the following two groups: BZD effective group and BZD non-effective group. The choice of treatment was dependent on physicians' discretion according to the protocol for SE in our institution.

RESULTS

Sixty-eight SE episodes in 10 patients were assessed. The median age at SE was 31 months. Of 68 episodes, 42 episodes (61.8%) were in the BZD effective group and 26 (38.2%) in the BZD non-effective group. There were no significant differences in clinical features. In the BZD non-effective group, the effective rates of continuous midazolam, phenobarbital, phenytoin/fosphenytoin were 9/9 episodes (100%), 14/17 (82.4%), and 2/5 (40.0%), respectively. Adverse effects were identified in 19/68 episodes (27.9%), including 11/42 episodes in the BZD effective group and 8/26 in the BZD non-effective group, which was no statistical difference between the two groups. Respiratory suppression was found in all 19 episodes and the incidence of endotracheal intubation in the BZD non-effective group (15.4%) was higher than that in the BZD effective group (2.4%) (p = 0.046).

CONCLUSION

BZD may be used as first choice, and phenobarbital prior to continuous midazolam as second choice for SE with Dravet syndrome. There might be no predictable clinical features showing that BZD will be effective.

Genotype-phenotype correlation of CACNA1A variants in children with epilepsy

AIM

To explore the genotypes and phenotypes of CACNA1A variants in children with epilepsy.

METHOD

Eighteen children (six males, 12 females) with CACNA1A variants were identified using next-generation sequencing.

RESULTS

There were 14 missense variants, two nonsense variants, one frameshift variant, and one splice site variant. Sixteen variants were de novo. Age at seizure onset ranged from 1 day to 8 years; median age was 8 months. Multiple seizure types were observed, including focal, generalized tonic-clonic, myoclonic, and absence seizures, as well as epileptic spasms and tonic seizures. Focal motor status epilepticus occurred in 10 individuals and generalized motor status epilepticus occurred in two individuals. All 18 children showed developmental delay. Focal motor status epilepticus resulted in cerebral atrophy in five individuals, mainly on the contralateral side. Interictal electroencephalogram showed focal discharges in 12 individuals, whereas five individuals had generalized discharges. Three individuals were seizure-free, whereas 15 still had seizures and five had recurrent status epilepticus at last follow-up.

INTERPRETATION

Most children with epilepsy and CACNA1A variants had early seizure onset and developmental delay. Focal seizure was the most common seizure type. Most patients experienced status epilepticus. Unilateral cerebral atrophy could occur after focal motor status epilepticus. Patients with CACNA1A variants located in the transmembrane region may be at high risk of status epilepticus.

RHOBTB2 gene associated epilepsy and paroxysmal movement disorder: two cases report and literature review

Background

RHOBTB2 gene is associated with developmental and epileptic encephalopathy-64(DEE-64), which is characterized by epilepsy, developmental delay, microcephaly, unspecific facial dysmorphism, and paroxysmal movement disorders. Most previous studies showed that the phenotypes of RHOBTB2 gene include developmental and epileptic encephalopathy(DEE) and DEE with paroxysmal movement disorders. Only one study showed that patient with RHOBTB2 variant had paroxysmal movement disorders with no epilepsy.

Case presentations

Two cases with RHOBTB2 variants are presented here: Case one was diagnosed as DEE, he had recurrent afebrile focal status epilepticus and paroxysmal extrapyramidal symptoms in infancy. Interictal electroencephalogram (EEG) showed focal discharges. Brain magnetic resonance imaging (MRI) showed cortical dysplasia. Epilepsy of case one was refractory. Nevertheless, case two only showed paroxysmal movement disorders alone in adolescence. Video EEG showed focal discharges during an interictal dystonic episode and he brain MRI was normal.

Conclusion

The phenotypes of RHOBTB2 gene include DEE, paroxysmal movement disorders, and DEE with paroxysmal movement disorders. RHOBTB2 can be one of the pathogenic genes of paroxysmal movement disorders.

De novo homozygous variant of the SCN1A gene in a patient with severe Dravet syndrome complicated by acute encephalopathy

Variants in the SCN1A gene have been identified in epilepsy patients with widely variable phenotypes and they are generally heterozygous. Here, we report a homozygous missense variant, NM_001165963.4: c.4319C>T (p.Ala1440Val), in the SCN1A gene which seemed to occur de novo together with a gene conversion event. It's highly possible that this variant, although located in a critical functional domain of protein Nav1.1, depending on the nature of the amino acid substitution, may not cause the complete loss of protein function. And the accumulated effect by having this variant on both alleles results in a Dravet syndrome phenotype which is more severe than average. This first report of a de novo homozygous variant in the SCN1A gene, therefore, provides a clear illustration of a complex genotype-phenotype relationship.

Managing CLN2 disease: a treatable neurodegenerative condition among other treatable early childhood epilepsies

INTRODUCTION

Neuronal ceroid lipofuscinosis type 2 (CLN2 disease) is a rare pediatric neurodegenerative condition, which is usually fatal by mid-adolescence. Seizures are one of the most common early symptoms of CLN2 disease, but patients often experience language deficits, movement disorders, and behavioral problems. Diagnosis of CLN2 disease is challenging (particularly when differentiating between early-onset developmental, metabolic, or epileptic syndromes), and diagnostic delays often overlap with rapid disease progression. An enzyme replacement therapy (cerliponase alfa) is now available, adding CLN2 disease to the list of potentially treatable disorders requiring a prompt diagnosis.

AREAS COVERED

Although advances in enzymatic activity testing and genetic testing have facilitated diagnoses of CLN2 disease, our review highlights the presenting symptoms that are vital in directing clinicians to perform appropriate tests or seek expert opinion. We also describe common diagnostic challenges and some potential misdiagnoses that may occur during differential diagnosis.

EXPERT OPINION

An awareness of CLN2 disease as a potentially treatable disorder and increased understanding of the key presenting symptoms can support selection of appropriate tests and prompt diagnosis. The available enzyme replacement therapy heralds an even greater imperative for early diagnosis, and for clinicians to direct patients to appropriate diagnostic pathways.

Safety considerations selecting antiseizure medications for the treatment of individuals with Dravet syndrome

Introduction: Management of individuals with Dravet Syndrome has evolved significantly over the past 10 years. Progress has been made in understanding the pathophysiology, the long-term outcome and possible consequences of inappropriate therapies, new drugs have been approved by the regulatory authorities and patients and families expressed their needs beyond seizures' control.Areas covered: The authors aimed at providing an overview of the main antiseizure medications used in Dravet syndrome with a particular focus on safety considerations. As the highly active phase of seizures takes place before the age of 5 years, the characteristics of antiseizure medications in infancy and childhood have also been considered due to their impact on antiseizure medication safety.Expert opinion: Recent treatments, evaluated via randomized clinical trials, are promising in terms of efficacy and safety in individuals with DS. However, the balance between expected benefits and risks taken must be accurately assessed on an individual basis. There is a lack of data to understand the needs of patients and families, a major point particularly in this population, where the evaluation of efficacy and safety beyond seizures is difficult due to cognitive delay and behavioral disorders and where this evaluation is coming almost exclusively from caregivers.

Acute encephalopathy in children with tuberous sclerosis complex

Objective

We examined the clinical manifestations of acute encephalopathy (AE) and identify risk factors for AE in children with tuberous sclerosis complex (TSC).

Methods

The clinical data of 11 children with clinically diagnosed TSC associated with AE and 109 children with clinically diagnosed TSC alone aged 4 years or older were collected from 13 hospitals.

Results

Of the 11 children with AE, 5 had histories of febrile seizures (FS), and all had histories of febrile status epilepticus (FSE). AE developed within 24 h after fever onset in all children with seizures lasting 30 min or longer. All children developed coma after seizure cessation. Head magnetic resonance imaging (MRI) revealed widespread abnormalities in the cerebral cortex, subcortical white matter, corpus callosum, basal ganglia, and thalamus. One child died; seven had severe neurological sequelae; and the other three, mild sequelae. Logistic regression analysis revealed that a history of FSE was correlated with the development of AE.

Significance

AE in children with TSC was characterized by sudden onset after fever, followed by coma, widespread brain edema evident on MRI, and poor outcomes. A history of FSE was a risk factor for the development of AE.

Etiology of Non-Traumatic Seizures in Children Admitted to PICU: An Eight-Year Retrospective Study

Purpose

Seizure is a serious neurological symptom in the pediatric intensive care unit (PICU), yet data on etiologies of non-traumatic childhood seizures in China are scarce. We aimed to investigate the etiological trends of seizures in children admitted to the PICU in our tertiary center.

Patients and Methods

We performed a retrospective analysis of all patients (aged 29 days to 14 years) with non-traumatic seizures, admitted to the PICU of Xiangya Hospital from 2010 to 2017. Etiological analysis was performed to compare data between 2010–2013 and 2014–2017.

Results

The study included 318 patients (male: female = 1.27:1) with mean age of 5.4 ± 4.0 years. The most frequent causes observed were CNS infections (109/318, 34.3%), unknown reason epilepsy (96/318, 30.2%), and immune (56/318, 17.6%). Comparison of the 2010–2013 and 2014–2017 periods revealed a significant decrease in the percentage of CNS infections [48.8% (59/121) vs 25.4% (50/197), p < 0.001] and a significant increase in the incidence of unknown reason epilepsy [(24/121, 19.8%) vs (72/197, 36.5%), p < 0.001] and immune causes [(12/121, 9.9%) vs (44/197, 22.3%), p = 0.005].

Conclusion

CNS infections were the most common cause of seizures during 2010–2013, while non-infectious diseases such as epilepsy and immune disorders represented the leading causes during 2014–2017. Continuous improvement in medical technology and understanding of disease patterns would greatly improve early diagnosis and therapeutic management of such conditions.

Fatal Status Epilepticus in Dravet Syndrome

Dravet Syndrome (DS) is burdened by high epilepsy-related premature mortality due to status epilepticus (SE). We surveyed centres within Europe through the Dravet Italia Onlus and EpiCARE network (European Reference Network for Rare and Complex Epilepsies). We collated responses on seven DS SCN1A+ patients who died following refractory SE (mean age 6.9 year, range 1.3–23.4 year); six were on valproate, clobazam, and stiripentol. All patients had previous SE. Fatal SE was always triggered by fever: either respiratory infection or one case of hexavalent vaccination. SE lasted between 80 min and 9 h and all patients received IV benzodiazepines. Four patients died during or within hours of SE; in three patients, SE was followed by coma with death occurring after 13–60 days. Our survey supports the hypothesis that unresponsive fever is a core characteristic feature of acute encephalopathy. We highlight the need for management protocols for prolonged seizures and SE in DS.

Case-control association study of rare nonsynonymous variants of SCN1A and KCNQ2 in acute encephalopathy with biphasic seizures and late reduced diffusion

PURPOSE

Acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) is characterized by prolonged febrile seizures at onset and subsequent damage to the cerebral cortex of infants and children. The pathogenesis is suspected to be excitotoxicity leading to neuronal death. SCN1A and KCNQ2 are causative genes of genetic epilepsy including Dravet syndrome and Ohtahara syndrome. Here we conducted a case-control rare-variant association study of the two genes in AESD.

METHODS

The coding regions of SCN1A and KCNQ2 were sequenced by the Sanger method for 175 and 111 patients, respectively, with AESD. As control subjects, we used genetic data from 3554 subjects provided by the Integrative Japanese Genome Variation Database (iJGVD). Then we performed a case-control association study of rare missense and splice region variants (minor allele frequency < 0.005) of each gene with AESD using Weighted Sum Statistics (WSS) and Sequence Kernel Association Test (SKAT).

RESULTS

SCN1A rare variants had a significant association with AESD after correction for multiple tests (WSS, permutated p value 4.00 × 10^-3: SKAT, p value 2.51 × 10^-4). The association was more significant when we focused on deleterious variants (WSS, permutated p = 9.00 × 10^-4; SKAT, p = 4.99 × 10^-5). Although KCNQ2 rare nonsynonymous variants tended to be more frequent in patients than in controls, there was no significant difference.

CONCLUSION

Our study provided statistical evidence of an association between SCN1A and AESD for the first time, and established SCN1A as one of the susceptibility genes for AESD.

Focal Status Epilepticus-Related Unilateral Brain Edema: Magnetic Resonance Imaging Study of Children in Southwest China

BACKGROUND

Unilateral brain edema is a rare peri-ictal imaging abnormality related to focal status epilepticus. We present the largest series of these patients, describe their clinical features and magnetic resonance imaging (MRI) findings, and analyze the possible underlying pathophysiology.

METHODS

We reviewed the medical records in Southwest China's largest tertiary's children's medical center from 2011 to 2017. Patients with focal status epilepticus were included if acute-phase cerebral MRI showed unilateral edematous swelling of the epileptic hemisphere.

RESULTS

Eleven children were included. The age at which the patients presented with status epilepticus ranged from seven months to 10.8 years. All patients showed prolonged clonic seizures with marked unilateral predominance followed by hemiplegia of the ipsilateral limbs. The seizure duration ranged from one to 72 hours. All patients showed hyperintensities on T2-weighted images and diffusion-weighted images involving the whole pathologic hemisphere. Three patients showed involvement of the contralateral cerebellar hemisphere and one showed hippocampal herniation. Magnetic resonance angiography of the brain was performed in seven patients, among which three showed dilation of the affected hemispheric arteries. Three patients underwent follow-up MRI, and all the examinations revealed ipsilateral cerebral hemisphere atrophy.

CONCLUSIONS

Focal status epilepticus may cause unilateral brain edema, and cytotoxic edema probably plays an important role in the pathophysiology of brain injury.