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Objectives: Dravet syndrome (DS) is a rare form of refractory epilepsy that begins in the first year of life. Approximately 85% of patients have a mutation in the SCN1A gene, which encodes a voltage-gated sodium channel. The main objective of the present work was to assess the degree of knowledge of DS among Spanish primary care (PC) professionals, the communication flow between them and the pediatric neurologists (PNs), and the services available and resources offered to patients in Spain when searching for a diagnosis and adequate treatment., Methods: Two anonymized online surveys on DS diagnosis and patient management in PC were conducted with Spanish PC pediatricians (PCPs) and caregivers of DS patients in Spain., Results: Most PCPs are aware of genetic epilepsy but lack full knowledge of DS and patient advocacy groups (PAGs). Access to epilepsy treatments varies among regions, with many referrals to hospitals and pediatric neurologists. Diagnosis is often delayed, with misdiagnoses and frequent emergency room (ER) visits. Treatment involves multiple drugs, and sodium channel blockers are used, which are contraindicated in DS treatment. Improved training, resources, and communication are needed for early diagnosis., Significance: To improve the care and treatment of DS patients in Spain, early diagnosis is required and, possibly, specific efforts aimed at identifying patients in adulthood, generating socio-sanitary structures that integrate social and health services to provide comprehensive care, taking into account the different features and comorbidities of the disease., Plain Language Summary: Dravet syndrome (DS) is a form of genetic epilepsy that starts within the first year of life. We present a study showing that, while family doctors are aware of genetic epilepsies, many don't have a complete understanding of DS. Unfortunately, getting the right diagnosis can take a long time, leading to unnecessary visits to the emergency room. Patients often need several medications, and sometimes they're given drugs that aren't recommended for DS. The takeaway is that training for doctors, more resources, and improved communication could help creating better healthcare systems and therefore give easier access to the right therapies., (© 2024 The Author(s). Epilepsia Open published by Wiley Periodicals LLC on behalf of International League Against Epilepsy.)

Introduction: Lennox-Gastaut syndrome (LGS) and Dravet syndrome (DS) are rare, childhood-onset conditions associated with severe, treatment-resistant epilepsy and developmental issues, including motor and cognitive impairment. Tuberous sclerosis complex (TSC) is a rare genetic disease commonly associated with epilepsy and other neuropsychiatric disorders. This cross-sectional, interview-based study examined the qualitative impact of caring for patients with LGS, DS, and TSC-associated epilepsy on caregivers in Japan, from the perspective of both caregivers and physicians., Methods: The survey included a pre-interview worksheet to describe caregivers' emotional journeys, followed by a ≤ 60-minute one-on-one interview. Eligible participants were Japanese caregivers of patients with LGS, DS, or TSC treated for epilepsy symptoms, and Japan-residing pediatricians or neurologists treating ≥ 3 patients with LGS, DS, and/or TSC. Interview question responses were subjected to content analysis to identify the most common response tendencies and themes., Results: Twenty-six caregivers responded (mean [standard deviation (SD)] age, 45.9 [9.5] years; age range 29-68; 92 % female), caring for patients with LGS (n = 5), DS (n = 10), and TSC (n = 11); patient mean (SD) age, 13.6 (10.0) years; age range 2-44; 27 % adults; 50 % female. Nineteen physicians, treating patients with LGS (n = 9), DS (n = 7), and TSC (n = 10), participated. Caregivers and physicians generally aligned on the factors affecting caregivers' emotional states / quality of life (QoL). The most frequently reported caregiver emotions at the time of diagnosis were shock and discouragement, anxiety for the future, and relief at receiving a diagnosis. Negative emotions throughout disease progression up until the time of survey were mainly caused by worsening of seizures, burden of constant caregiving / lack of free time, and patient's developmental issues. Positive emotions were linked to effective treatment / reduced seizures; more free time owing to the use of facilities, services, or other caregiving support; and developmental progress. Physicians acknowledged that caregivers required consultation services to support their emotional needs. In terms of unmet needs, caregiver and physician responses were aligned on the insufficient availability of services/facilities, the lack of effective treatments, and the uncertainties of adult patient care., Conclusions: Caregivers of patients with LGS, DS, or TSC-associated epilepsy in Japan reported a high degree of emotional burden related to frequent seizures, developmental issues, and constant caregiving. The burden of suboptimal treatment effectiveness, limited access to support services, and uncertainties in long-term care emphasize important unmet treatment needs., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: [All authors met the International Committee of Medical Journal Editors (ICMJE) authorship criteria and had full access to relevant data. Neither honoraria nor payments were made for authorship. M. LoPresti and Y. Sonohara are employees of INTAGE Healthcare Inc., which received funding from Jazz Pharmaceuticals, Inc. to conduct the fieldwork and data analysis. A. Igarashi has no conflicts of interest. S. Bowditch is an employee of Jazz Pharmaceuticals UK Ltd., and holds stocks/stock options with Jazz Pharmaceuticals UK Ltd.]., (Copyright © 2024 Jazz Pharmaceuticals, Inc. Published by Elsevier Inc. All rights reserved.)

Background: Dravet syndrome is a rare infantile onset epilepsy syndrome encompassing treatment resistant epilepsy and neurodevelopmental difficulties. There is limited data regarding caregiver experiences of diagnosis, treatment and supports for the associated neurodevelopmental problems., Method: Semi-structured interviews were conducted with caregivers of 36/48 children (75% of total population in Sweden) with Dravet syndrome. Data was analysed using thematic analysis., Results: Regarding the diagnostic experience, themes were: Delays in diagnostic process, genetic testing not optimal, communication of Dravet syndrome diagnosis and support and information soon after diagnosis. Caregivers felt that delays in diagnosis and testing could have been avoided whilst experiences of communication of diagnosis and support after diagnosis varied. In terms of treatment for seizures, the themes were: Satisfied with treatment, emergency treatment, treatment with antiseizure medications, strategies to control seizures via temperature regulation/avoidance of infections and use of equipment and aids. Caregivers were in the main accepting that seizures in Dravet syndrome are very difficult to treat and that seizure freedom is often an unachievable goal. Many felt frustrated that they were expected to take responsibility with respect to choice of medication. They often employed strategies (e.g., avoidance of physical activity) to reduce seizures or their impact. In terms of supports for neurodevelopmental problems, the themes were: Struggled to access support, lack of integrated healthcare and satisfaction with school. Many caregivers felt that accessing necessary supports for their children and developmental and behavioural needs was a struggle and that the provision of support often lacked integration e.g., lack of collaboration between child's disability service and school. Caregivers also expressed a desire that there would be better knowledge of Dravet syndrome in emergency departments and schools, that care would be better integrated and that there would be more supports for assessment and interventions regarding the associated neurodevelopmental problems., Conclusion: The responses of caregivers of children with Dravet syndrome highlight the need for supports from diagnosis for both epilepsy and neurodevelopmental problems. Good examples of provision were identified but parents often felt they lacked support and support often came from providers who lacked knowledge of the syndrome. Collaboration between medical, disability and school services was often lacking., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Objective: The aim was to investigate the monitoring, interventions, and occurrence of critical, potentially life-threatening incidents in patients with Dravet syndrome (DS) and caregivers' knowledge about sudden unexpected death in epilepsy (SUDEP)., Methods: This multicenter, cross-sectional study of patients with DS and their caregivers in Germany consisted of a questionnaire and prospective diary querying the disease characteristics and demographic data of patients and caregivers., Results: Our analysis included 108 questionnaires and 82 diaries. Patients with DS were 49.1% male (n = 53), with a mean age of 13.5 (SD ± 10.0 years) and primary caregivers were 92.6% (n = 100) female, with a mean age of 44.7 (SD ± 10.6 years). Monitoring devices were used regularly by 75.9% (n = 82) of caregivers, and most monitored daily/nightly. Frequently used devices were pulse oximeters (64.6%), baby monitors (64.6%), thermometers (24.1%), and Epi-Care (26.8%). Younger caregiver and patient age and history of status epilepticus were associated with increased use of monitoring, and 81% of monitor users reported having avoided a critical incident with nocturnal monitoring. The need for resuscitation due to cardiac or respiratory arrest was reported by 22 caregivers (20.4%), and most cases (72.7%) were associated with a seizure. Caregivers reported frequently performing interventions at night, including oropharyngeal suction, oxygenation, personal hygiene, and change of body position. Most caregivers were well informed about SUDEP (n = 102; 94%) and monitored for a lateral or supine body position; however, only 39.8% reported receiving resuscitation training, whereas 52.8% (n = 57) knew what to do in case the child's breathing or heart activity failed., Significance: Critical incidents and the need for resuscitation are reported frequently by caregivers and may be related to high mortality and SUDEP rates in DS. Resuscitation training is welcomed by caregivers and should be continuously provided. Oxygen monitoring devices are frequently used and considered useful by caregivers., (© 2023 The Authors. Epilepsia published by Wiley Periodicals LLC on behalf of International League Against Epilepsy.)

Dravet syndrome (DS) is a genetic rare disease, which is usually caused by a mutation in the SCN1A gene. DS is characterised by a drug-resistant epilepsy and by cognitive and behavioural disturbances. Thus, DS patients require both pharmacological and non-pharmacological treatments. However, there is a paucity of studies on non-pharmacological therapies and their potential benefits. The main aim of this study was to describe the non-pharmacological therapy modalities received by DS patients and their socio-economic impact on the family. Thus, we designed an online survey addressed to caregivers of DS patients. Our results indicated that up to 91.9% of the surveyed patients required non-pharmacological therapies, which were mainly directed to treat cognitive, sensory and motor impairments. In many cases, the economic costs of these therapies were borne entirely by the families. Nevertheless, patients required a deployment of resources not only at a health care level, but also at an educational level., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: [JAA is president of the Dravet Syndrome Foundation Spain (DSF). He and/or the DSF have received grants and/or financial support from GW Pharma, Zogenix, Ovid Therapeutics, Encoded Therapeutics, Biocodex, Praxis, Stoke, Takeda, UCB, Epygenix, Jazz Pharmaceuticals and StrideBio to help carry out some of the DSF's foundational activities or provide consulting services. JAA honoraria have always been donated directly or indirectly to the DSF. CBS, AM, SG, EC, ET and FP have no conflicts of interest.]., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Dravet syndrome (DS), also known as severe myoclonic epilepsy of infancy, is a rare and drug-resistant form of developmental and epileptic encephalopathies, which is both debilitating and challenging to manage, typically arising during the first year of life, with seizures often triggered by fever, infections, or vaccinations. It is characterized by frequent and prolonged seizures, developmental delays, and various other neurological and behavioral impairments. Most cases result from pathogenic mutations in the sodium voltage-gated channel alpha subunit 1 ( SCN1A ) gene, which encodes a critical voltage-gated sodium channel subunit involved in neuronal excitability. Precision medicine offers significant potential for improving DS diagnosis and treatment. Early genetic testing enables timely and accurate diagnosis. Advances in our understanding of DS's underlying genetic mechanisms and neurobiology have enabled the development of targeted therapies, such as gene therapy, offering more effective and less invasive treatment options for patients with DS. Targeted and gene therapies provide hope for more effective and personalized treatments. However, research into novel approaches remains in its early stages, and their clinical application remains to be seen. This review addresses the current understanding of clinical DS features, genetic involvement in DS development, and outcomes of novel DS therapies.

Dravet syndrome is a rare form of severe genetic epilepsy characterized by recurrent and long-lasting seizures. It appears around the first year of life, with a quick evolution toward an increase in the frequency of the seizures, accompanied by a delay in motor and cognitive development, and does not respond well to antiepileptic medication. Most patients carry a mutation in the gene SCN1A encoding the α subunit of the voltage-gated sodium channel Nav1.1, resulting in hyperexcitability of neural circuits and seizure onset. In this work, we applied transcranial static magnetic stimulation (tSMS), a non-invasive, safe, easy-to-use and affordable neuromodulatory tool that reduces neural excitability in a mouse model of Dravet syndrome. We demonstrate that tSMS dramatically reduced the number of crises. Furthermore, crises recorded in the presence of the tSMS were shorter and less intense than in the sham condition. Since tSMS has demonstrated its efficacy at reducing cortical excitability in humans without showing unwanted side effects, in an attempt to anticipate a possible use of tSMS for Dravet Syndrome patients, we performed a numerical simulation in which the magnetic field generated by the magnet was modeled to estimate the magnetic field intensity reached in the cerebral cortex, which could help to design stimulation strategies in these patients. Our results provide a proof of concept for nonpharmacological treatment of Dravet syndrome, which opens the door to the design of new protocols for treatment., Competing Interests: Declaration of Competing Interest The authors declare that they have no competing financial interests., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

The SCN1A gene encodes the alpha subunit of a voltage-gated sodium channel (Na v 1.1), which is essential for the function of inhibitory neurons in the brain. Mutations in this gene cause severe encephalopathies such as Dravet syndrome (DS). Upregulation of SCN1A expression by different approaches has demonstrated promising therapeutic effects in preclinical models of DS. Limiting the effect to inhibitory neurons may contribute to the restoration of brain homeostasis, increasing the safety and efficacy of the treatment. In this work, we have evaluated different approaches to obtain preferential expression of the full SCN1A cDNA (6 Kb) in GABAergic neurons, using high-capacity adenoviral vectors (HC-AdV). In order to favour infection of these cells, we considered ErbB4 as a surface target. Incorporation of the EGF-like domain from neuregulin 1 alpha (NRG1α) in the fiber of adenovirus capsid allowed preferential infection in cells lines expressing ErbB4. However, it had no impact on the infectivity of the vector in primary cultures or in vivo. For transcriptional control of transgene expression, we developed a regulatory sequence (DP3V) based on the Distal-less homolog enhancer (Dlx), the vesicular GABA transporter (VGAT) promoter, and a portion of the SCN1A gene. The hybrid DP3V promoter allowed preferential expression of transgenes in GABAergic neurons both in vitro and in vivo. A new HC-AdV expressing SCN1A under the control of this promoter showed improved survival and amelioration of the epileptic phenotype in a DS mouse model. These results increase the repertoire of gene therapy vectors for the treatment of DS and indicate a new avenue for the refinement of gene supplementation in this disease. KEY MESSAGES: Adenoviral vectors can deliver the SCN1A cDNA and are amenable for targeting. An adenoviral vector displaying an ErbB4 ligand in the capsid does not target GABAergic neurons. A hybrid promoter allows preferential expression of transgenes in GABAergic neurons. Preferential expression of SCN1A in GABAergic cells is therapeutic in a Dravet syndrome model., (© 2023. The Author(s).)

Patients with Dravet syndrome (DS) and their caregivers must navigate a complex process upon transitioning from pediatric to adult healthcare settings. Our study examines the state of care transfer of patients with DS in the U.S. A 34-question e-survey evaluating patient demographics, clinical features, and details of the transfer process was sent to caregivers of adults with DS (≥18 years old) residing in the U.S. through the Dravet Syndrome Foundation. Forty-six responses were included in the analysis. Twenty-nine patients (n = 29/46) did not undergo transfer of care - mostly because they were still followed by pediatric neurologists/epileptologists (71%), whereas 17 (n = 17/46) underwent transfer of care. Adult neurology/epilepsy teams providing care never/rarely included a multidisciplinary team (71%), addressed patients' self-advocacy capabilities (53%), or legal guardianship/end-of-life decision-making (59%). Adult neurology/epilepsy teams were considered very much attentive/available (63%), attentive and accommodating to patients with behavioral/cognitive issues (50%), and knowledgeable about caring for patients with intellectual disability/behavioral issues (63%), collaborating with caregivers (75%), and DS - especially in adults (50%). Most caregivers (62.5%) rated the transfer process as good, very good, or excellent. Patients with DS and their caregivers would benefit from more accessible transition programs, which would be ideally equipped to deliver care tailored to these patients' needs., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have seemed to influence the work reported in this paper., (Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.)

Dravet syndrome (DS), an intractable childhood epileptic encephalopathy with a high fatality rate, is typically caused by loss-of-function mutations in one allele of SCN1A, which encodes NaV1.1, a 250-kDa voltage-gated sodium channel. In contrast to other epilepsies, pharmaceutical treatment for DS is limited. Here, we demonstrate that viral vector-mediated delivery of a codon-modified SCN1A open reading frame into the brain improves DS comorbidities in juvenile and adolescent DS mice (Scn1aA1783V/WT). Notably, bilateral vector injections into the hippocampus and/or the thalamus of DS mice increased survival, reduced the occurrence of epileptic spikes, provided protection from thermally induced seizures, corrected background electrocorticographic activity and behavioral deficits, and restored hippocampal inhibition. Together, our results provide a proof of concept for the potential of SCN1A delivery as a therapeutic approach for infants and adolescents with DS-associated comorbidities.

For more than 10 years, research has been conducted on gene therapies for the most severe forms of epilepsy, which until now have proven resistant to treatment. First gene therapies are now in clinical trials for pharmacoresistant focal epilepsies and Dravet syndrome. In this article, we describe how these and many more gene therapies work and what they target., Competing Interests: Die Autorinnen/Autoren geben an, dass kein Interessenkonflikt besteht., (Thieme. All rights reserved.)

Mutations in the SCN1A gene can cause a variety of phenotypes, ranging from mild forms, such as febrile seizures and generalized epilepsy with febrile seizures plus, to severe, such as Dravet and non-Dravet developmental epileptic encephalopathies. Until now, more than two thousand pathogenic variants of the SCN1A gene have been identified and different pathogenic mechanisms (loss vs. gain of function) described, but the precise molecular mechanisms responsible for the deficits exhibited by patients are not fully elucidated. Additionally, the phenotypic variability proves the involvement of other genetic factors in its final expression. This is the reason why animal models and cell line models used to explore the molecular pathology of SCN1A -related disorders are only of limited use. The results of studies based on such models cannot be directly translated to affected individuals because they do not address each patient's unique genetic background. The generation of functional neurons and glia for patient-derived iPSCs, together with the generation of isogenic controls using CRISPR/Cas technology, and finally, the 3D brain organoid models, seem to be a good way to solve this problem. Here, we review SCN1A -related encephalopathies, as well as the stem cell models used to explore their molecular basis.

Dravet Syndrome is a genetic epileptic syndrome characterized by severe and intractable seizures associated with cognitive, motor, and behavioral impairments. The disease is also linked with increased mortality mainly due to sudden unexpected death in epilepsy. Over 80% of cases are due to a de novo mutation in one allele of the SCN1A gene, which encodes the α-subunit of the voltage-gated ion channel Na V 1.1. Dravet Syndrome is usually refractory to antiepileptic drugs, which only alleviate seizures to a small extent. Viral, non-viral genetic therapy, and gene editing tools are rapidly enhancing and providing new platforms for more effective, alternative medicinal treatments for Dravet syndrome. These strategies include gene supplementation, CRISPR-mediated transcriptional activation, and the use of antisense oligonucleotides. In this review, we summarize our current knowledge of novel genetic therapies that are currently under development for Dravet syndrome., (Copyright © 2022 The Author(s). Published by Elsevier Inc. All rights reserved.)

Objective: This study was undertaken to gain consensus from experienced physicians and caregivers regarding optimal diagnosis and management of Dravet syndrome (DS), in the context of recently approved, DS-specific therapies and emerging disease-modifying treatments., Methods: A core working group was convened consisting of six physicians with recognized expertise in DS and two representatives of the Dravet Syndrome Foundation. This core group summarized the current literature (focused on clinical presentation, comorbidities, maintenance and rescue therapies, and evolving disease-modifying therapies) and nominated the 31-member expert panel (ensuring international representation), which participated in two rounds of a Delphi process to gain consensus on diagnosis and management of DS., Results: There was strong consensus that infants 2-15 months old, presenting with either a first prolonged hemiclonic seizure or first convulsive status epilepticus with fever or following vaccination, in the absence of another cause, should undergo genetic testing for DS. Panelists agreed on evolution of specific comorbidities with time, but less agreement was achieved on optimal management. There was also agreement on appropriate first- to third-line maintenance therapies, which included the newly approved agents. Whereas there was agreement for recommendation of disease-modifying therapies, if they are proven safe and efficacious for seizures and/or reduction of comorbidities, there was less consensus for when these should be started, with caregivers being more conservative than physicians., Significance: This International DS Consensus, informed by both experienced global caregiver and physician voices, provides a strong overview of the impact of DS, therapeutic goals and optimal management strategies incorporating the recent therapeutic advances in DS, and evolving disease-modifying therapies., (© 2022 The Authors. Epilepsia published by Wiley Periodicals LLC on behalf of International League Against Epilepsy.)

Dravet syndrome (DS) is a developmental and epileptic encephalopathy caused by monoallelic loss-of-function variants in the SCN1A gene. SCN1A encodes for the alpha subunit of the voltage-gated type I sodium channel (Na V 1.1), the primary voltage-gated sodium channel responsible for generation of action potentials in GABAergic inhibitory interneurons. In these studies, we tested the efficacy of an adeno-associated virus serotype 9 (AAV9) SCN1A gene regulation therapy, AAV9-RE GABA -eTF SCN1A , designed to target transgene expression to GABAergic inhibitory neurons and reduce off-target expression within excitatory cells, in the Scn1a +/- mouse model of DS. Biodistribution and preliminary safety were evaluated in nonhuman primates (NHPs). AAV9-RE GABA -eTF SCN1A was engineered to upregulate SCN1A expression levels within GABAergic inhibitory interneurons to correct the underlying haploinsufficiency and circuit dysfunction. A single bilateral intracerebroventricular (ICV) injection of AAV9-RE GABA -eTF SCN1A in Scn1a +/- postnatal day 1 mice led to increased SCN1A mRNA transcripts, specifically within GABAergic inhibitory interneurons, and Na V 1.1 protein levels in the brain. This was associated with a significant decrease in the occurrence of spontaneous and hyperthermia-induced seizures, and prolonged survival for over a year. In NHPs, delivery of AAV9-RE GABA -eTF SCN1A by unilateral ICV injection led to widespread vector biodistribution and transgene expression throughout the brain, including key structures involved in epilepsy and cognitive behaviors, such as hippocampus and cortex. AAV9-RE GABA -eTF SCN1A was well tolerated, with no adverse events during administration, no detectable changes in clinical observations, no adverse findings in histopathology, and no dorsal root ganglion-related toxicity. Our results support the clinical development of AAV9-RE GABA -eTF SCN1A (ETX101) as an effective and targeted disease-modifying approach to SCN1A + DS.

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 V 1.1 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"., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Dravet syndrome (DS) is a developmental and epileptic encephalopathy with evolving disease course as individuals age. In recent years, the treatment landscape of DS has changed considerably, and a comprehensive systematic review of the contemporary literature is lacking. Here we synthesized published evidence on the occurrence of clinical impacts by age, the economic and humanistic (health-related quality-of-life [HRQoL]) burden, and health state utility. We provide an evidence-based, contemporary visualization of the clinical manifestations, highlighting that DS is not limited to seizures; non-seizure manifestations appear early in life and increase over time, contributing significantly to the economic and humanistic burden of disease. The primary drivers of HRQoL in DS include seizure severity, cognition, and motor and behavioral problems; in turn, these directly affect caregivers through the extent of assistance required and consequent impact on activities of daily living. Unsurprisingly, costs are driven by seizure-related events, hospitalizations, and in-home medical care visits. This systematic review highlights a paucity of longitudinal data; most studies meeting inclusion criteria were cross-sectional or had short follow-up. Nonetheless, available data illustrate the substantial impact on individuals, their families, and healthcare systems and establish the need for novel therapies to address the complex spectrum of DS manifestations., Competing Interests: Conflict of Interest MCV, BM, JSG, ESJ, and SR are employees of Encoded Therapeutics. SMS and AMD are employees of Broadstreet HEOR, which received funds from Encoded for the conduct of this study. JS and SMZ received consulting fees related to this work., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Dravet syndrome (DS) is a severe, rare, and complex developmental and epileptic encephalopathy affecting 1 in 16 000 live births and characterized by a drug-resistant epilepsy, cognitive, psychomotor, and language impairment, and behavioral disorders. Evidence suggests that optimal treatment of seizures in DS may improve outcomes, even though neurodevelopmental impairments are the likely result of both the underlying genetic variant and the epilepsy. We present an updated guideline for DS diagnosis and treatment, taking into consideration care of the adult patient and nonpharmaceutical therapeutic options for this disease. This up-to-date guideline, which is based on an extensive review of the literature and culminates with a new treatment algorithm for DS, is a European consensus developed through a survey involving 29 European clinical experts in DS. This guideline will serve professionals in their clinical practice and, as a consequence, will benefit DS patients and their families., (© 2021 The Authors. Epilepsia Open published by Wiley Periodicals LLC on behalf of International League Against Epilepsy.)

Background: Dravet Syndrome is a severe childhood pharmaco-resistant epileptic disorder mainly caused by mutations in the SCN1A gene, which encodes for the α1 subunit of the type I voltage-gated sodium channel (Na V 1.1), that causes imbalance between excitation and inhibition in the brain. We recently found that eEF2K knock out mice displayed enhanced GABAergic transmission and tonic inhibition and were less susceptible to epileptic seizures. Thus, we investigated the effect of inhibition of eEF2K on the epileptic and behavioral phenotype of Scn1a ± mice, a murine model of Dravet Syndrome., Methods: To elucidate the role of eEF2K pathway in the etiopathology of Dravet syndrome we generated a new mouse model deleting the eEF2K gene in Scn1a ± mice. By crossing Scn1a ± mice with eEF2K-/- mice we obtained the three main genotypes needed for our studies, Scn1a+/+ eEF2K+/+ (WT mice), Scn1a ± eEF2K+/+ mice (Scn1a ± mice) and Scn1a ± eEF2K-/- mice, that were fully characterized for EEG and behavioral phenotype. Furthermore, we tested the ability of a pharmacological inhibitor of eEF2K in rescuing EEG alterations of the Scn1a ± mice., Results: We showed that the activity of eEF2K/eEF2 pathway was enhanced in Scn1a ± mice. Then, we demonstrated that both genetic deletion and pharmacological inhibition of eEF2K were sufficient to ameliorate the epileptic phenotype of Scn1a ± mice. Interestingly we also found that motor coordination defect, memory impairments, and stereotyped behavior of the Scn1a ± mice were reverted by eEF2K deletion. The analysis of spontaneous inhibitory postsynaptic currents (sIPSCs) suggested that the rescue of the pathological phenotype was driven by the potentiation of GABAergic synapses., Limitations: Even if we found that eEF2K deletion was able to increase inhibitory synapses function, the molecular mechanism underlining the inhibition of eEF2K/eEF2 pathway in rescuing epileptic and behavioral alterations in the Scn1a ± needs further investigations., Conclusions: Our data indicate that pharmacological inhibition of eEF2K could represent a novel therapeutic intervention for treating epilepsy and related comorbidities in the Dravet syndrome., (© 2021. The Author(s).)

Objective: Ten-year retrospective study to assess burden of illness in patients with probable Dravet syndrome (DS) identified from German healthcare data., Methods: In the absence of an International Classification of Diseases code, patients with probable DS were identified using a selection algorithm considering diagnoses and drug prescriptions. Primary analyses were prevalence and demographics; secondary analyses included healthcare costs, annual hospitalization rate (AHR) and length of stay (LOS), medication use, and mortality., Results: In the final study year, 64 patients with probable DS (mean [range] age: 33.2 [3-82] years; male: 48%) were identified. Prevalence: 4.7 per 100,000 people. During the study, 160 patients with probable DS were identified and followed up for 1,261 patient-years. Mean cost of healthcare was €11,048 per patient-year (PPY), mostly attributable to inpatient care (47%), medication (26%), and services and devices (19%). Annual healthcare costs were significantly greater for those with prescribed rescue medication (15% of patient-years) vs. without (€16,123 vs. €10,125 PPY, p < 0.001). Mean (standard deviation [SD]) AHR and LOS were 1.1 (1.7) and 17.5 (33.5) days PPY. AHR was significantly greater in patients with prescribed rescue medication vs. without (1.6 [2.0] vs. 1.0 [1.6] PPY, p < 0.001). Mean (SD) number of antiseizure medications prescribed was 2.6 (1.2) PPY and 5.0 (2.5) over the entire observable time for each patient. Mortality rate was significantly higher for probable DS vs. matched controls (11.88% [19 events] vs. 1.19% [172 events], p < 0.001)., Conclusion: Probable DS is associated with substantial healthcare costs in Germany., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: SSB reports personal fees from UCB, Eisai, Desitin Pharma, Zogenix, and GW Pharmaceuticals companies. LK reports support for attending meetings and/or travel from Eisai and UCB Pharma. ASi is an employee of Vilua Healthcare GmbH. GW and RH are employees of GW Pharma Ltd. FR reports personal fees from Arvelle Therapeutics, Eisai, and GW Pharmaceuticals companies; personal fees and travel expenses from UCB; and grants from the Detlev-Wrobel Fonds for Epilepsy Research, BMBF – ERA PerMed Programme, Hessisches Ministerium für Wissenschaft und Kunst (LOEWE-Programme), and the European Union. ASt reports personal fees and grants from Arvelle Therapeutics, Desitin Arzneimittel, Eisai, GW Pharmaceuticals companies, Marinus Pharma, Medtronic, UCB, and Zogenix., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Introduction: Dravet syndrome (DS) is still seen as a "pediatric disease", where patients receive excellent care in pediatric centers, but care is less than optimal in adult health care systems (HCS). This creates a barrier when young adults need to leave the family-centered pediatric system and enter the adult, patient-centered HCS. Here we create a guide to help with the transition from pediatric to adult for patients with DS., Methods: Experts in Dravet syndrome flagged the main barriers in caring for adults with DS and created a 2-page transition summary guide based on their expertise and a literature review., Results: The 2-page guide addresses: DS diagnosis in children and adults; clinical manifestations, including the differences in seizures types and frequencies between children and adults with DS; the natural history of intellectual disability, behavior, gait, motor disorders and dysautonomia; a review of optimal treatments (including medications not commonly used in adult epilepsy settings such as stiripentol and fenfluramine), as well as emergency seizure management; avoidance of triggers, preventive measures, and vaccine administration in adults with DS., Conclusion: Several young adults with DS are still followed by their child neurologist. This 2-page transition guide should help facilitate the transition of patients with DS to the adult HCS and should be given to families as well as adult health care providers that may not be familiar with DS., (Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.)

Dravet syndrome (DS) is an intractable developmental and epileptic encephalopathy significantly impacting affected children and their families. A novel, one-time, adeno-associated virus (AAV)-mediated gene regulation therapy was designed to treat the underlying cause of DS, potentially improving the full spectrum of DS manifestations. To ensure the first-in-human clinical trial addresses meaningful outcomes for patients and families, we examined their perspectives, priorities, goals, and desired outcomes in the design phase through a mixed methods approach (quantitative and qualitative). We conducted a non-identifiable parent caregiver survey, shared through a patient advocacy organization (n = 36 parents; children age ≤6 years). Parents were also engaged via three group discussions (n = 10; children age 2-20 years) and optional follow-up in-depth individual interviews (n = 6). Qualitative data analysis followed an inductive interpretive process, and qualitative researchers conducted a thematic analysis with a narrative approach. Survey results revealed most children (94%) were diagnosed by age 1, with onset of seizures at mean age 6.2 months and other DS manifestations before 2 years. The most desired disease aspects to address with potential new disease-modifying therapies were severe seizures (ranked by 92% of caregivers) and communication issues (development, expressive, receptive; 72-83%). Qualitative results showed the need for trial outcomes that recognize the impact of DS on the whole family. Parents eventually hope for trials including children of all ages and were both excited about the potential positive impact of a one-time disease-modifying therapy and mindful of potential long-term implications. Participants reflected on the details and risks of a clinical trial design (e.g., sham procedures) and described the different factors that relate to their decision to participate in a trial. Their main aspirations were to stop neurodevelopmental stagnation, to reduce seizures, and to reduce the impact on their families' wellbeing. To our knowledge, this is the first study within a patient-oriented research framework that specifically explored parents' needs and perceptions regarding clinical trials of a potential disease-modifying therapy for children with a severe, developmental disease, such as DS., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Dravet syndrome (DS) is a severe developmental and epileptic encephalopathy that is mainly associated with variants in SCN1A. While drug-resistant epilepsy is the most notable feature of this syndrome, numerous symptoms are present that have significant impact on patients' quality of life. In spite of novel, third-generation anti-seizure treatment options becoming available over the last several years, seizure freedom is often not attained and non-seizure symptoms remain. Precision medicine now offers realistic hope for seizure freedom in DS patients, with several approaches demonstrating preclinical success. Therapeutic approaches such as antisense oligonucleotides (ASO) and adeno-associated virus (AAV)-delivered gene modulation have expanded the potential treatment options for DS, with some of these approaches now transitioning to clinical trials. Several of these treatments may risk the exacerbation of gain-of-function variants and may not be reversible, therefore emphasizing the need for functional testing of new pathogenic variants. The current absence of treatments that address the overall disease, in addition to seizures, exposes the urgent need for reliable, valid measures of the entire complement of symptoms as outcome measures to truly know the impact of treatments on DS. Additionally, with so many treatment options on the horizon, there will be a need to understand how to select appropriate patients for each treatment, whether treatments are complementary or adverse to each other, and long-term risks of the treatment. Nevertheless, precision therapeutics hold tremendous potential to provide long-lasting seizure freedom and even complete cures for this devastating disease., (© 2021. The American Society for Experimental NeuroTherapeutics, Inc.)

Objectives: To understand the risks, impact and outcome of COVID-19 in people affected by Dravet Syndrome (DS)., Materials and Methods: An anonymous cross-sectional online survey was conducted between June 17 and July 13, 2020, addressed to families of people with DS., Results: A total of 116 responses were collected, from families of children (n = 86; 74%) and adults (30; 26%) with DS. The majority (106; 91%) were shielded at the family home during lockdown. Symptoms compatible with COVID-19 were reported in 22 (19%) individuals. Only four individuals with symptoms had a PCR swab test, none of which was positive. Only one symptomatic person had antibody testing (but not swab testing), which was positive. One person had repeatedly positive swab tests whilst in hospital for renal failure, but had no typical symptoms of COVID-19. In 50% of people with DS who developed possible or probable COVID-19 symptoms, seizure worsening was reported, in terms of increased seizure frequency or duration or both. Medical attention was required in 9/22 (41%), all of whom were children., Conclusions: In this cohort of people with DS, we observed an infection rate, determined by compatible symptoms, of 19%, with no deaths and benign outcome in most cases despite the underlying complex epilepsy although children often required medical attention. Early adoption of preventative measures, including testing of symptomatic individuals, regular surveillance for people living in residential care facilities, and shielding of individuals with comorbidities increasing the risk of severe outcome, may limit the impact of COVID-19., (© 2021 The Authors. Acta Neurologica Scandinavica published by John Wiley & Sons Ltd.)

The objective of this study was to estimate the direct cost before and after diagnosis assessment in patients with Dravet's syndrome (DS). The basis of the economic study was to calculate the costs of health care before and after diagnosis of DS. We retrospectively evaluated all SCN1A positive patients with phenotype of DS treated in our hospital. Statistical analyses were performed by IBM SPSS Statistics 24.0 software. After the diagnosis of DS, there was a significant decline of health care costs (-85.6%) an average of €29.4 ± 26.1 monthly per patient. We estimated the monthly costs at €204.5 ± 167 (median: €193.9, range: €35.5-534.4) per patient before DS diagnosis. The major cost was for hospitalization in neurological department: €43.3 ± 52 (median: €21.9, range: €9.5-179.4) per patient. Minimal cost per patient per months before DS diagnosis was cost of psychological testing/care and complementary rehabilitation (0.13 and 0.6% of total cost). After DS diagnosis, the major cost was focused on nonhospitalization care of patients (64.8%), minimal (€0) for genetic testing and major for outpatient care (18%, mean: €5.3, median: €7). DS results in essential health care utilization and high financial burden before diagnosis elucidation caused by repeated hospitalization and extensive diagnostics tests of "epileptic encephalopathy of unknown etiology." The results of this study point out that early assessment of the diagnosis leads to significant decrease of the financial costs because of adequate therapeutic management and exclusion of redundant diagnostic testing after elucidation of correct diagnosis., Competing Interests: Dr. Aulicka has received research support from the project “Junior research program.”, (Thieme. All rights reserved.)

Objective: Clinical care of rare and complex epilepsies is challenging, because evidence-based treatment guidelines are scarce, the experience of many physicians is limited, and interdisciplinary treatment of comorbidities is required. The pathomechanisms of rare epilepsies are, however, increasingly understood, which potentially fosters novel targeted therapies. The objectives of our survey were to obtain an overview of the clinical practice in European tertiary epilepsy centers treating patients with 5 arbitrarily selected rare epilepsies and to get an estimate of potentially available patients for future studies., Methods: Members of the European Reference Network for rare and complex epilepsies ( EpiCARE) were invited to participate in a web-based survey on clinical practice of patients with Dravet syndrome, tuberous sclerosis complex (TSC), autoimmune encephalitis, and progressive myoclonic epilepsies including Unverricht Lundborg and Unverricht-like diseases. A consensus-based questionnaire was generated for each disease., Results: Twenty-six of 30 invited epilepsy centers participated. Cohorts were present in most responding centers for TSC (87%), Dravet syndrome (85%), and autoimmune encephalitis (71%). Patients with TSC and Dravet syndrome represented the largest cohorts in these centers. The antiseizure drug treatments were rather consistent across the centers especially with regard to Dravet syndrome, infantile spasms in TSC, and Unverricht Lundborg / Unverricht-like disease. Available, widely used targeted therapies included everolimus in TSC and immunosuppressive therapies in autoimmune encephalitis. Screening for comorbidities was routinely done, but specific treatment protocols were lacking in most centers., Significance: The survey summarizes the current clinical practice for selected rare epilepsies in tertiary European epilepsy centers and demonstrates consistency as well as heterogeneity in the treatment, underscoring the need for controlled trials and recommendations. The survey also provides estimates for potential participants of clinical trials recruited via EpiCARE, emphasizing the great potential of Reference Networks for future studies to evaluate new targeted therapies and to identify novel biomarkers., Competing Interests: Sameer M Zuberi has conducted randomized controlled trials for GW Pharma and Zogenix Ltd in patients with Dravet syndrome. He has participated in advisory boards for Zogenix, GW Pharma, Biocodex, and Encoded Genomics. Katarzyna Kotulska was supported by the 7th Framework Programme of European Commission within the Large‐scale Integrating Project EPISTOP (Proposal No: 602 391‐2; Proposal title: “Long term, prospective study evaluating clinical and molecular biomarkers of epileptogenesis in a genetic model of epilepsy – tuberous sclerosis complex”; www.EPISTOP.eu) and the Polish Ministerial funds for science (years 2014‐2018) for the implementation of international co‐financed project and the grant EPIMARKER of the Polish National Center for Research and Development No STRATEGMED3/306306/4/2016. All other authors have no conflict of interest related to this survey to disclose. We confirm that we have read the Journal's position on issues involved in ethical publication and affirm that this report is consistent with those guidelines., (© 2020 The Authors. Epilepsia Open published by Wiley Periodicals LLC on behalf of International League Against Epilepsy.)

Objective: Epilepsy with myoclonic-atonic seizures (EMAS) is a rare childhood onset epileptic encephalopathy. There is no clear consensus for recommended treatments, and pharmacoresistance is common. To better assess the clinical phenotype, most effective treatment, and determinants of cognitive and seizure outcomes, three major pediatric epilepsy centers combined data, creating the largest cohort of patients with EMAS ever studied to date., Methods: Authors performed a retrospective chart review of patients with EMAS who received care at the authors' institutions., Results: A total of 166 children were identified. Global developmental delay (>1 domain) was present in 2% of children at onset and 49% during the course of the disease. Afebrile seizures occurred after the age of 2 years in 88%, generalized tonic-clonic seizures in 60%, and drop attack or myoclonic seizures in 30%. At onset, electroencephalography (EEG) found 28% normal, background slowing in 20%, and epileptiform discharges or seizures in 69%. Subsequent EEG found slowing in 62% and discharges or seizures in 90%. Response (>50% seizure reduction) to the first three antiseizure drugs (ASDs) was 26% (levetiracetam, 17%; valproic acid, 31%; other ASDs combined, 26%). Diet therapy was used as a second or third therapy in 19% and ultimately used in 57%; response was 79%, significantly greater than the first three ASDs (P = .005, χ 2 ). Seizure freedom occurred in 57% and was less likely in the case of persistent global developmental delays (P < .001), seizure recorded on subsequent EEGs (P = .027), and failure to respond to diet therapy (P = .005). Development was normal in 47%, and 12% had delays in one domain, which was less likely in the case of global developmental delay after epilepsy onset (P < .001) and failure to achieve seizure freedom (P < .001)., Significance: This large cohort of children with EMAS clarifies areas of variability in practice. Diet therapy is by far the most effective treatment; failure to respond was associated with failure to attain seizure freedom. This therapy should be used early in the treatment in EMAS. This study also identified a bidirectional link between cognitive and seizure outcomes., (© 2020 International League Against Epilepsy.)

Introduction: Dravet syndrome (DS), a prototypic developmental and genetic epileptic encephalopathy (DEE), is characterized by an early onset of treatment-refractory seizures, together with impairments in motor control, behavior, and cognition. Even with multiple conventional anti-epileptic drugs, seizures remain poorly controlled, and there has been a considerable unmet need for effective and tolerable treatments., Areas Covered: This targeted literature review aims to highlight recent changes to the therapeutic landscape for DS by summarizing the most up-to-date, evidence-based research, including pivotal data from the clinical development of stiripentol, cannabidiol, and fenfluramine, which are important milestones for DS treatment, together with the latest findings of other pharmacotherapies in development. In phase III, double-blind, placebo-controlled randomized controlled trials stiripentol, cannabidiol, and fenfluramine have shown clinically relevant reductions in convulsive seizure frequency, and are generally well tolerated. Stiripentol was associated with responder rates (greater than 50% reduction in convulsive seizure frequency) of 67%-71%, when added to valproic acid and clobazam; cannabidiol was associated with responder rates of 43%-49% (48%-63% in conjunction with clobazam), and fenfluramine of 54%-68% across studies. Therapies in development include soticlestat, ataluren, verapamil, and clemizole, with strategies to treat the underlying cause of DS, including gene therapy and antisense oligonucleotides beginning to emerge from preclinical studies., Expert Opinion: Despite the challenges of drug development in rare diseases, this is an exciting time for the treatment of DS, with the promise of new efficacious and well-tolerated therapies, which may pave the way for treatment advances in other DEEs.

Caregivers of individuals with intellectual and developmental disabilities and epilepsy such as Dravet syndrome (DS) must navigate a complex web of state and community services through the transition from child-centered to adult-oriented healthcare. This study examined barriers to successful transition from the caregivers' perspective. Primary caregivers of teenagers or adults with DS who had contemplated or completed transition to adult care were eligible. A three-week, asynchronous, web-based focus group was conducted on Facebook. Data were analyzed in an iterative process based on a Grounded Theory approach. Participants reviewed findings for accuracy. Transition success was defined by how well it ensured adequate care for the child when caregivers became unable to provide it. Existing transition programs were described as "not for our kids." All caregivers reported that transition programs began too late. Challenges to identifying suitable providers were formidable, with 71% of adult patients still being seen by pediatric neurologists. Many adult physicians lacked a general knowledge of DS, yet caregivers perceived that adult physicians were unwilling to listen to caregivers, and few were comfortable accommodating patients with intellectual disabilities and challenging behaviors. Community programs often excluded patients with DS, and rural healthcare disparities created additional barriers. Analysis produced recommendations for improving the transition process including the creation of a certified Transition Navigator position in the clinical setting. The limitations of this focus group analysis include possible selection bias, but our study identified key issues and pathways to improve the transition process for patients with DS and their caregivers., Competing Interests: Declaration of competing interest Danielle Boyce has no current financial conflicts of interest but previously worked as a consultant for Lundbeck Pharmaceuticals and Eton Pharmaceuticals. She currently serves as an unpaid scientific advisor and data analyst to the Gould Syndrome Foundation and COPD Foundation. Orrin Devinsky has financial interests (stock options, investment, advisory board positions, and/or consulting arrangements) with the following business entities: Privateer Holdings, Tilray, Inc., Empatica, Tevard, Engage, Receptor Life Sciences, Egg Rock/Papa & Barkley, RETTCO, PAIRNOMIX, Greenwich Biosciences, and Zogenix. He is a noncompensated scientific advisory board member of the following groups: Sudden Unexplained Death in Children Foundation, KBG Foundation, Tuberous Sclerosis Alliance, Dup15 Alliance, Epilepsy Foundation SUDEP Institute, CDKL5 Program of Excellence, KCNQ2 Cure Alliance, CURE DHPS, HNRNPU Foundation, KBG Foundation, and Finding A Cure for Epilepsy and Seizures. Mary Anne Meskis is a founding member and Executive Director of the Dravet Syndrome Foundation., (Copyright © 2020 The Author(s). Published by Elsevier Inc. All rights reserved.)

Background: The aim of this study was to understand the impact of Dravet syndrome (DS) on patients with Dravet syndrome and their families, with a focus on the social and economic impact on both mothers and fathers., Methods: A French language on-line survey was distributed (October 2014-January 2015) for completion by caregivers of patients aged <18 years with DS. The survey was hosted on the French Dravet Syndrome Alliance website, and the survey link was provided to patients and caregivers during clinics at the Necker Hospital (Paris, France)., Results: Survey responses were available for 91 patients (median age 7.6 years; 81.6% SCN1A mutation positive). Total seizure frequency was >2 per week for 16.1% of patients, 1-8 per month for 55.2% and < 1 per month for 28.7%; tonic-clonic and myoclonic were the most frequent seizure types. Patients showed various degrees of intellectual disability and DS had a high impact on concentration and school learning in 70.1% and 80.5%. In addition, patients showed appetite disorders in 73.6%, sleep disorders in 72.4% and behavior disorders in 62.1%. Most parents were married (80.5%) with higher rates than the French general population (53.5%). Educational achievement and socio-professional categories for the parents were higher than observed in the French general population, while monthly net income was similar. Preparation of medication was generally done by the mother and father (46.0% of patients) or the mother only (37.9%). Most caregivers reported very low or no difficulty with treatment preparation and low or no risk of error. Parents typically spent <30 min per day on treatment preparation and administration and around 4 h per week for attending therapy appointments. Although most patients and parents were perceived to have good general health, mothers had a worse perception of their own general health than fathers. Compared with fathers, mothers reported a greater impact of caring for a child with DS on their social life, relationships with family and friends, time and energy, and professional life., Conclusion: Families caring for a child with DS experience considerable social and economic impact, with an apparent greater burden of care on the mother than the father., Competing Interests: Disclosures of conflicts of interest All authors met the ICMJE authorship criteria. Neither honoraria nor payments were made for authorship. RN received research grants from EU (Horizons2020, FP7) and from UCB, Eisai, Livanova and GW Pharmaceuticals, has served as a consultant/advisor/lecturer for Novartis, Takeda, Zogenix, Nutricia, Advicenne, Eisai and GW Pharmaceuticals companies and as a study investigator for GW Research Ltd., Advicenne, UCB, Eisai and Zogenix. NO COI for this work. MD has no COI to declare. NC has served as a lecturer for Nutricia, Novartis, Zogenix, Advicenne, Livanova and GW Pharmaceuticals companies. NO COI for this work. TT served as a lecturer for Nutricia. NO COI for this work. FB has acted as a consultant for GW Pharmaceuticals companies. MM has acted as a consultant for GW Pharmaceuticals companies. RH is an employee of GW Pharma Ltd. NCo has no COI to declare; she is the scientific officer of the Dravet Alliance, France., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Objective: Vagus nerve stimulation (VNS) is a nonpharmacologic therapeutic option for patients who have pharmaco-resistant Dravet syndrome (DS). Plentiful efforts have been made for delivering VNS to DS patients, but its effectiveness still requires further verification. We investigated the effectiveness of the VNS treatment of DS patients using brain connectivity analysis with electroencephalography (EEG)., Approach: Twenty pharmaco-resistant DS patients were selected to undergo VNS implantation and classified into responder and non-responder groups after 24 months post-VNS. The effect of VNS between 6 months pre- and 6, 12, and 24 months post-VNS in all patients, responders, and non-responders on four different frequency categories of four brain parameters were compared using resting-state EEG., Main Results: In alpha and beta bands, all patients showed positive results for characteristic path length (CPL), global efficiency (GE), and transitivity after VNS treatment, and changes in betweenness centrality (BC) were not significant. The difference in transitivity between responders and non-responders is more pronounced than those in CPL and GE are, in both the alpha (p < 0.015) and beta (p < 0.001) bands. There was an obvious change in BC, especially in the alpha band, as the hubs tended to move from frontal lobe to parietal lobe for responders; however, there was no change for the non-responders., Significance: We investigated the alteration in brain connectivity of DS patients in alpha and beta bands during a long-term follow-up and found the responders have a decreased transitivity after the VNS treatment. Moreover, the hubs with high values in the alpha band tended to move from frontal lobe to parietal lobe for responders after VNS treatment.

Epilepsy is a common disorder in children and adults that causes significant morbidity and affects many aspects of a patient's lives. Two-thirds of patients with epilepsy are controlled with established antiseizure medications, leaving a significant number of patients searching for other options. The purpose of this review is to provide an overview of recent advancements in the management of treatment-resistant epilepsy in pediatric patients. Recent publications have shown the efficacy of new pharmaceutical options such as fenfluramine and cannabidiol, some of which have been tested specifically in patients with childhood-onset epilepsy syndromes such as Dravet's syndrome and Lennox-Gastaut's syndrome. Furthermore, recent approval by the U.S. Food and Drug Administration of stiripentol has made available a previously difficult-to-obtain option for patients with Dravet's syndrome. Finally, implanted responsive neurostimulation devices for direct cortical stimulation and deep brain stimulation have shown efficacy in adult patients and may represent a thrilling new horizon for pediatric patients., Competing Interests: Dr. Sullivan reports grants from Zogenix and personal fees from Epygenix, outside the submitted work., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

Dravet syndrome (DS), previously known as severe myoclonic epilepsy of infancy, is a severe developmental and epileptic encephalopathy caused by loss-of-function mutations in one copy of SCN1A (haploinsufficiency), located on chromosome 2q24, with decreased function of Nav1.1 sodium channels in GABAergic inhibitory interneurons. Pharmacoresistant seizures in DS start in the infancy in the form of hemiclonic febrile status epilepticus. Later, other intractable seizure types develop including myoclonic seizures. Early normal development in infancy evolves into moderate to severe intellectual impairment, motor impairment, behavioral abnormalities, and later a characteristic crouching gait. Clobazam, valproate, levetiracetam, topiramate, zonisamide, ketogenic diet, and vagus nerve stimulation had been shown to be effective, but even with polytherapy, only 10% of patients get adequate seizure control. The author provides a narrative review of the current treatment paradigm as well as recent advances in the management of DS based on a comprehensive literature review (MEDLINE using PubMed and OvidSP vendors with appropriate keywords to incorporate recent evidence), personal practice, and experience. In recent years, the treatment paradigm of DS is changing with the approval of pharmaceutical-grade cannabidiol oil and stiripentol. Another novel antiepileptic drug (AED), fenfluramine, had also shown excellent efficacy in phase 3 studies of DS. However, these AEDs primarily control seizures without addressing the underlying pathogenesis and other important common comorbidities such as cognitive impairment, autistic behavior, neuropsychiatric abnormalities, and motor impairment including crouching gait. Several agents targeted for DS are in the developmental stage: TAK935, lorcaserin, clemizole, huperzine analog, ataluren, selective sodium channel modulators and activators, antisense oligonucleotide therapy, and adenoviral vector therapy. As DS is associated with a high risk of sudden unexpected death in epilepsy, seizure detection devices can be used in this population for testing and clinical validation of these devices., Competing Interests: Debopam Samanta has no potential conflict of interest with respect to the research, authorship, and/or publication of this article., (Georg Thieme Verlag KG Stuttgart · New York.)

Dravet syndrome (DS) is a neurodevelopmental genetic disorder caused by mutations in the SCN1A gene encoding the α subunit of the NaV1.1 voltage-gated sodium channel that controls neuronal action potential firing. The high density of this mutated channel in GABAergic interneurons results in impaired inhibitory neurotransmission and subsequent excessive activation of excitatory neurons. The syndrome is associated with severe childhood epilepsy, autistic behaviors, and sudden unexpected death in epilepsy. Here, we compared the rescue effects of an adeno-associated viral (AAV) vector coding for the multifunctional β1 sodium channel auxiliary subunit (AAV-NaVβ1) with a control vector lacking a transgene. We hypothesized that overexpression of NaVβ1 would facilitate the function of residual voltage-gated channels and improve the DS phenotype in the Scn1a +/- mouse model of DS. AAV-NaVβ1 was injected into the cerebral spinal fluid of neonatal Scn1a +/- mice. In untreated control Scn1a +/- mice, females showed a higher degree of mortality than males. Compared with Scn1a +/- control mice, AAV-NaVβ1-treated Scn1a +/- mice displayed increased survival, an outcome that was more pronounced in females than males. In contrast, behavioral analysis revealed that male, but not female, Scn1a +/- mice displayed motor hyperactivity, and abnormal performance on tests of fear and anxiety and learning and memory. Male Scn1a +/- mice treated with AAV-NaVβ1 showed reduced spontaneous seizures and normalization of motor activity and performance on the elevated plus maze test. These findings demonstrate sex differences in mortality in untreated Scn1a +/- mice, an effect that may be related to a lower level of intrinsic inhibitory tone in female mice, and a normalization of aberrant behaviors in males after central nervous system administration of AAV-NaVβ1. The therapeutic efficacy of AAV-NaVβ1 in a mouse model of DS suggests a potential new long-lasting biological therapeutic avenue for the treatment of this catastrophic epilepsy.

Mitochondria are best known for their role in energy production, and they are the only mammalian organelles that contain their own genomes. The mitochondrial genome mutation rate is reported to be 10-17 times higher compared to nuclear genomes as a result of oxidative damage caused by reactive oxygen species during oxidative phosphorylation. Pathogenic mitochondrial DNA mutations result in mitochondrial DNA disorders, which are among the most common inherited human diseases. Interventions of mitochondrial DNA disorders involve either the transfer of viable isolated mitochondria to recipient cells or genetically modifying the mitochondrial genome to improve therapeutic outcome. This review outlines the common mitochondrial DNA disorders and the key advances in the past decade necessary to improve the current knowledge on mitochondrial disease intervention. Although it is now 31 years since the first description of patients with pathogenic mitochondrial DNA was reported, the treatment for mitochondrial disease is often inadequate and mostly palliative. Advancements in diagnostic technology improved the molecular diagnosis of previously unresolved cases, and they provide new insight into the pathogenesis and genetic changes in mitochondrial DNA diseases ., Competing Interests: The authors declare no conflicts of interest.

Dravet syndrome (DS) is a severe epileptic encephalopathy caused mainly by heterozygous loss-of-function mutations of the SCN1A gene, indicating haploinsufficiency as the pathogenic mechanism. Here we tested whether catalytically dead Cas9 (dCas9)-mediated Scn1a gene activation can rescue Scn1a haploinsufficiency in a mouse DS model and restore physiological levels of its gene product, the Na v 1.1 voltage-gated sodium channel. We screened single guide RNAs (sgRNAs) for their ability to stimulate Scn1a transcription in association with the dCas9 activation system. We identified a specific sgRNA that increases Scn1a gene expression levels in cell lines and primary neurons with high specificity. Na v 1.1 protein levels were augmented, as was the ability of wild-type immature GABAergic interneurons to fire action potentials. A similar enhancement of Scn1a transcription was achieved in mature DS interneurons, rescuing their ability to fire. To test the therapeutic potential of this approach, we delivered the Scn1a-dCas9 activation system to DS pups using adeno-associated viruses. Parvalbumin interneurons recovered their firing ability, and febrile seizures were significantly attenuated. Our results pave the way for exploiting dCas9-based gene activation as an effective and targeted approach to DS and other disorders resulting from altered gene dosage., (Copyright © 2019 The American Society of Gene and Cell Therapy. Published by Elsevier Inc. All rights reserved.)

To describe the outcome of Dravet syndrome (DS) in adolescents and adults we conducted a longitudinal retrospective study of two independent cohorts of 34 adolescents (group 1) and 50 adults (group 2). In both cohorts, we collected information about genetic mutation, and semiology of seizures at onset and during disease course. At the last evaluation, we considered the following features: epilepsy (distinguishing myoclonic/complete and nonmyoclonic/incomplete phenotype), neurologic signs, intellectual disability (ID), and behavioral disorders. Moreover, in both cohorts, we performed a correlation analysis between early characteristics of the disease and the outcome of DS with regard to seizure persistence, ID, behavioral disorder, and neurologic impairment at last evaluation. Group 1 includes 22 adolescents with complete form of DS and 12 with incomplete form; group 2 includes 35 adults with complete form and 15 with incomplete form. The seizures persisted in 73.6% of adolescents and in 80% of adults, but epilepsy severity progressively decreased through age. Seizure persistence correlated with the complete phenotype and with the occurrence of reflex seizures. At last evaluation, ID was moderate or severe in 70.5% of adolescents and in 80% of adults. The most severe cognitive and motor impairment was observed in patients with persisting seizures. The severity of cognition, language, and neurologic impairment at last evaluation correlated statistically with the complete phenotype. The study confirms that the global outcome of DS is poor in most cases, albeit epilepsy severity decreases throughout adulthood. The improvement of epilepsy throughout ages is not associated with improvement in intellectual abilities and motor skills; this confirms that the unfavorable outcome is not a pure consequence of epilepsy., (Wiley Periodicals, Inc. © 2019 International League Against Epilepsy.)

Photosensitive epilepsy is the most common subset of reflex epilepsy in humans. It is characterized by an abnormal electroencephalogram trait known as photoparoxysmal response (PPR) corresponding to ictal symptomology in response to intermittent photic stimulation. Increased exposure to photic stimulation through technological and societal advance has had a significant impact on the incidence and interest in photosensitive epilepsy. Paralleled scientific developments have deepened our understanding of the neurophysiology underlying photosensitivity, especially in the context of deep genomic sequencing and neuroimaging. Furthermore, given the relatively predictable nature of photosensitive epilepsy, there is substantial interest in translating advancements in this field to epilepsy as a whole. Herein, we comprehensively review the epidemiology, clinical features and novel insights into the mechanism behind photosensitive epilepsy with a focus on the clinical implications of new advancements., (Published by Elsevier B.V.)

Objective: To obtain and assess opinions on EMAS diagnostic criteria, recommended investigations, and therapeutic options, from a large group of physicians who care for children with EMAS., Methods: The EMAS focus group of PERC created a survey to assess the opinions of pediatric neurologists who care for children with EMAS regarding diagnosis and treatment of this condition, which was sent to members of PERC, AES, and CNS. A Likert scale was used to assess the respondents' opinions on the importance of diagnostic and exclusion criteria (five point scale), investigations (four point scale), and treatment (six point scale) of EMAS. Inclusion/exclusion criteria were then classified as critical, strong, or modest. Investigations were classified as essential, recommended, or possible. Therapies were classified as first line, beneficial, indeterminate benefit, or contraindicated., Results: Survey results from the 76 participants determined the following: EMAS inclusion criteria: history suggestive of MAS (critical), recorded or home video suggestive of MAS, generalized discharges on inter-ictal EEG, normal neuroimaging, normal development prior to seizure onset (strong). EMAS exclusionary criteria: epileptic spasms, abnormal neuroimaging, focal abnormal exam, seizure onset six years (strong)., Recommended Investigations: EEG and MRI (essential), amino acids, organic acids, fatty acid/acylcarnitine profile, microarray, genetic panel, lactate/pyruvate, CSF and serum glucose/lactate (strong)., Recommended Treatments: Valproic acid (first line), topiramate, zonisamide, levetiracetam, benzodiazepines, and dietary therapies (beneficial)., Significance: To date, no similar surveys have been published, even though early syndrome identification and initiation of effective treatment have been associated with improved outcome in EMAS. Medications that exacerbate seizures in EMAS have also been identified. This survey identified critical and preferred diagnostic electro clinical features, investigations, and treatments for EMAS. It will guide future research and is a crucial first step in defining specific diagnostic criteria, recommended evaluation, and most effective therapies for EMAS., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Dravet syndrome (DS) is a medically refractory epilepsy that onsets in the first year of life with prolonged seizures, often triggered by fever. Over time, patients develop other seizure types (myoclonic, atypical absences, drops), intellectual disability, crouch gait and other co-morbidities (sleep problems, autonomic dysfunction). Complete seizure control is generally not achievable with current therapies, and the goals of treatment are to balance reduction of seizure burden with adverse effects of therapies. Treatment of co-morbidities must also be addressed, as they have a significant impact on the quality of life of patients with DS. Seizures are typically worsened with sodium-channel agents. Accepted first-line agents include clobazam and valproic acid, although these rarely provide adequate seizure control. Benefit has also been noted with stiripentol, topiramate, levetiracetam, the ketogenic diet and vagal nerve stimulation. Several agents presently in development, specifically fenfluramine and cannabidiol, have shown efficacy in clinical trials. Status epilepticus is a recurring problem for patients with DS, particularly in their early childhood years. All patients should be prescribed a home rescue therapy (usually a benzodiazepine) but should also have a written seizure action plan that outlines when rescue should be given and further steps to take in the local hospital if the seizure persists despite home rescue therapy.

Background: We investigated how two distinct mutations in SCN1A differentially affect electrophysiological properties of the patient-derived GABAergic neurons and clinical severities in two Dravet syndrome (DS) patients., Materials and Methods: We established induced pluripotent stem cells from two DS patients with different mutations in SCN1A and subsequently differentiated them into forebrain GABAergic neurons. Functionality of differentiated GABAergic neurons was examined by electrophysiological recordings., Results: DS-1 patient had a missense mutation, c.4261G > T [GenBank: NM&#95;006920.4] and DS-2 patient had a nonsense frameshift mutation, c.3576&#95;3580 del TCAAA [GenBank: NM&#95;006920.4]. Clinically, contrary to our expectations, DS-1 patient had more severe symptoms including frequency of seizure episodes and the extent of intellectual ability penetration than DS-2 patient. Electrophysiologic recordings showed significantly lower sodium current density and reduced action potential frequency at strong current injection (>60 pA) in GABAergic neurons derived from both. Intriguingly, unique genetic alterations of SCN1A differentially impacted electrophysiological impairment of the neurons, and the impairment's extent corresponded with the symptomatic severity of the donor from which the iPSCs were derived., Conclusion: Our results suggest the possibility that patient-derived iPSCs may provide a reliable in vitro system that reflects clinical severities in individuals with DS., (Copyright © 2017 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.)

Objective: The objective of this study was to explore the short-term effects of repetitive transcranial magnetic stimulation (rTMS) on action myoclonus., Methods: Nine patients with Unverricht-Lundborg (EPM1) progressive myoclonus epilepsy type underwent two series of 500 stimuli at 0.3Hz through round coil twice a day for five consecutive days. Clinical and neurophysiological examinations were performed two hours before starting the first rTMS session and two hours after the end of the last rTMS session., Results: Eight patients completed the protocol; one discontinued because of a transient increase in spontaneous jerks. The unified myoclonus rating scale indicated a 25% reduction in posttreatment myoclonus with action score associated with an increase in the cortical motor threshold and lengthening of the cortical silent period (CSP). The decrease in the myoclonus with action scores correlated with the prolongation of CSP., Conclusions: Repetitive transcranial magnetic stimulation can be safely used in patients with EPM1, improves action myoclonus, and partially restores deficient cortical inhibition., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Background: Dravet Syndrome (DS) is a rare developmental and epileptic encephalopathy characterized by multiple seizures, frequently prolonged and treatment refractory, with significant developmental disabilities and behavioral and psychiatric disorders. Patients with DS require intensive support and supervision from a caregiver, impacting significantly on both patients' and caregivers' lives. This study aimed to identify core concepts to measure the impact on both patients and caregivers in future DS clinical trials., Methods: Qualitative concept elicitation interviews were conducted with caregivers and healthcare professionals involved in caring for children with DS (aged 2-18years) in France to identify important concepts related to the global impact of DS. Interviews explored a range of concepts, including triggers, symptoms, impacts, and coping strategies, from which a conceptual model was developed. A Delphi consensus panel with eight international clinical experts aimed to identify important and relevant endpoints., Results: Seizure was the most commonly reported symptom with DS further impacting children's cognitive and behavioral functioning. Caregivers identified impact concepts not reported by healthcare professionals. Both groups described additional impacts on wider family members and home modifications. Clinical experts agreed on the inclusion of five patient- and caregiver-relevant concepts for measurement in future DS clinical trials in a composite endpoint. The five concepts for inclusion were; seizures, expressive communication of the child, receptive communication of the child, impact on daily activities, and social functioning of the caregiver., Conclusions: This study showed the wider potential impact of DS to extend beyond that of seizures, demonstrating that there is a need for additional patient- and caregiver-relevant concepts to be measured in clinical trials to fully identify the value of therapeutic interventions., (Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.)

Doose syndrome (epilepsy with myoclonic-atonic seizures) is an epilepsy syndrome with an incidence of approximately 1-2% of childhood-onset epilepsies. Although this syndrome is associated with multiple types of generalized seizures, the diagnosis is based on the presence of myoclonic-atonic seizures. Eighteen percent of patients have refractory seizures and intellectual disabilities. There have, however, been a few reports on the efficacy of surgical treatment for Doose syndrome. We describe a case of Doose syndrome in a 10-year-old boy. He developed generalized tonic-clonic seizures at 3years 8months of age and subsequently developed myoclonic-atonic, myoclonic, and tonic seizures. The frequent myoclonic seizures were refractory to multiple antiepileptic medications. His cognitive development was moderately delayed. Anterior four fifths corpus callosotomy was performed at 8years 5months of age. His seizures, especially myoclonic seizures, were markedly reduced. He was given vagus nerve stimulation therapy at 9years and 1month of age, which led to complete resolution of the myoclonic seizures. Corpus callosotomy can be a good treatment strategy in patients with Doose syndrome with medically refractory generalized seizures., (Copyright © 2017 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.)

Objective: The mutant γ-aminobutyric acid type A (GABA A ) receptor γ2(Q390X) subunit (Q351X in the mature peptide) has been associated with the epileptic encephalopathy, Dravet syndrome, and the epilepsy syndrome genetic epilepsy with febrile seizures plus (GEFS+). The mutation generates a premature stop codon that results in translation of a stable truncated and misfolded γ2 subunit that accumulates in neurons, forms intracellular aggregates, disrupts incorporation of γ2 subunits into GABA A receptors, and affects trafficking of partnering α and β subunits. Heterozygous Gabrg2 +/Q390X knock-in (KI) mice had reduced cortical inhibition, spike wave discharges on electroencephalography (EEG), a lower seizure threshold to the convulsant drug pentylenetetrazol (PTZ), and spontaneous generalized tonic-clonic seizures. In this proof-of-principal study, we attempted to rescue these deficits in KI mice using a γ2 subunit gene (GABRG2) replacement therapy., Methods: We introduced the GABRG2 allele by crossing Gabrg2 +/Q390X KI mice with bacterial artificial chromosome (BAC) transgenic mice overexpressing HA (hemagglutinin)-tagged human γ2 HA subunits, and compared GABA A receptor subunit expression by Western blot and immunohistochemical staining, seizure threshold by monitoring mouse behavior after PTZ-injection, and thalamocortical inhibition and network oscillation by slice recording., Results: Compared to KI mice, adult mice carrying both mutant allele and transgene had increased wild-type γ2 and partnering α1 and β2/3 subunits, increased miniature inhibitory postsynaptic current (mIPSC) amplitudes recorded from layer VI cortical neurons, reduced thalamocortical network oscillations, and higher PTZ seizure threshold., Significance: Based on these results we suggest that seizures in a genetic epilepsy syndrome caused by epilepsy mutant γ2(Q390X) subunits with dominant negative effects could be rescued potentially by overexpression of wild-type γ2 subunits., (Wiley Periodicals, Inc. © 2017 International League Against Epilepsy.)

Rationale: Dravet Syndrome (DS) is a severe epileptic encephalopathy of childhood involving intractable seizures, recurrent status epilepticus and cognitive decline. Because DS is a rare disease, available data is limited and evidence-based treatment guidelines are lacking. Vagus nerve stimulation (VNS) is an established neurostimulation treatment for intractable epilepsy, however little evidence is published on its efficacy in patients with DS., Methods: We performed a meta-analysis of all peer-reviewed English language studies reporting seizure outcomes of patients with DS treated with adjunctive vagus nerve stimulation. The primary and secondary outcome measures were ≥50% reduction of seizures or of the most-debilitating seizure type and seizure reduction per patient., Results: 13 studies comprising 68 patients met the inclusion criteria of which 11 were single-center retrospective case series, one was a multi-center retrospective analysis and one was a case report. 52.9% of patients experienced a ≥50% reduction of seizures and the average seizure reduction, which could only be assessed in n=28 patients was 50.8%. 7 out of 13 studies reported additional benefits of VNS, however this could not be assessed systematically., Conclusion: Vagus nerve stimulation appears to reduce seizure frequency in patients with DS. Based on this preliminary analysis, controlled trials of VNS in this rare condition using patient-centric outcome measures are indicated., (Copyright © 2017 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.)

Background: Dravet syndrome (DS) is a rare genetic epilepsy syndrome which is particularly pharmacoresistant. Vagus nerve stimulation (VNS) is commonly used in the treatment of DS as an adjunct to medical therapy. A meaningful assessment of post-surgical outcomes with VNS is difficult given the rarity of the condition., Objective: In a novel approach, we used social media to contact patients with DS to gather data on post-surgical seizure reduction and overall satisfaction with VNS., Methods: A survey consisting of 10 questions was posted to a social media webpage for a DS support group moderated by the Dravet Syndrome Foundation. The results were analyzed and percentages reported using the integrated SurveyMonkey analytical software., Results: 49 responses were received. We found that 28.5% of patients had a >50% reduction in seizure frequency after VNS placement, 55.8% felt that VNS therapy had helped to reduce seizure frequency, and 83.7% felt that seizure severity had improved. Of the respondents, 75% felt that they would undergo VNS implantation again for similar outcomes., Conclusions: We employed the novel technique of using social media to gather the largest set of self-reported outcomes of VNS therapy for Dravet syndrome. As corroborated by prior studies of VNS effectiveness in Dravet syndrome, there is significant albeit limited improvement in seizure control. Our study shows that despite this limitation, it is still considered a useful treatment adjunct from a caregiver's perspective., (Copyright © 2017 Elsevier B.V. All rights reserved.)