Publications by authors named "Marina Nikanorova"

33 Publications

The impact of severe pediatric epilepsy on experienced stress and psychopathology in parents.

Epilepsy Behav 2020 12 22;113:107538. Epub 2020 Nov 22.

Department of Epilepsy Genetics and Personalized Medicine, Danish Epilepsy Center, Filadelfia, Dianalund, Denmark. Electronic address:

Objectives: To assess the prevalence of psychopathology and the level of stress in parents of children with severe epilepsy to gain a better understanding of parental support needs.

Methods: Questionnaires were completed by parents of children with severe epilepsy during the hospitalization of their child at the Danish Epilepsy Center. The questions targeted symptoms of post-traumatic stress disorder (PTSD), complex PTSD (CPTSD), depression, and anxiety, and the level of perceived stress.

Results: A total of 162 caregivers of 140 children with epilepsy participated in the survey. Mothers were more often unemployed than fathers (38% vs. 11%, p < 0.01), and nearly half of the children (47%) attended special needs classes. Psychopathology symptoms were found in 43.5% of parents, fulfilling criteria for one or more diagnoses, and an additional 11% showed symptoms of sub-clinical PTSD. Parent-rated child difficulties were significantly associated with PTSD (M = 5.51, p = 0.001), depression (M = 4.50, p < 0.000), and anxiety (M = 4.61, p = 0.01), and with higher levels of perceived stress (p < 0.001).

Conclusion: Caring for a child with severe epilepsy has a significant psychopathological impact on caregivers. Caregivers' resources and the degree of behavioral difficulties in the child, rather than epilepsy-related factors, are highly correlated with distress and psychopathological symptoms in caregivers.
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http://dx.doi.org/10.1016/j.yebeh.2020.107538DOI Listing
December 2020

REM-sleep related hypermotor seizures: Video documentation and ictal source imaging.

Brain Dev 2020 Aug 25;42(7):503-507. Epub 2020 Apr 25.

Department of Clinical Neurophysiology, Danish Epilepsy Centre, Dianalund, Denmark; Department of Clinical Neurophysiology, Aarhus University Hospital and Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.

Introduction: Rapid eye movement (REM) sleep has an inhibitory effect on epileptiform EEG discharges, and seizures occur extremely rarely in REM sleep.

Case Study: We present the case and video recordings of a 10-year-old boy, with sleep-related hypermotor seizures starting from REM sleep, identified from videoEEG recordings. The semiology comprised intense fear, tachycardia, tachypnea, followed by hypermotor manifestations. Further investigations included brain MRI and source localization of the EEG signals. Multiple antiepileptic drugs were tried, the patient obtaining a good control of the seizures in the last 2.5 years with eslicarbazepine.

Discussion And Conclusion: The ictal EEG source imaging showed seizure onset in the anterior part of the right insula, with propagation to the orbitofrontal area, confirmed by the semiological sequence. Although rare, focal seizures can be triggered by REM sleep and our findings suggest that deficient maturation of brain areas involved in sleep modulation might induce insufficient desynchronization during REM sleep, thus allowing seizure emergence.
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http://dx.doi.org/10.1016/j.braindev.2020.04.003DOI Listing
August 2020

Pharmacoresponse in genetic generalized epilepsy: a genome-wide association study.

Pharmacogenomics 2020 04 20;21(5):325-335. Epub 2020 Apr 20.

Dr Margarete Fischer-Bosch Institute of Clinical Pharmacology, 70376 Stuttgart, Germany.

Pharmacoresistance is a major burden in epilepsy treatment. We aimed to identify genetic biomarkers in response to specific antiepileptic drugs (AEDs) in genetic generalized epilepsies (GGE). We conducted a genome-wide association study (GWAS) of 3.3 million autosomal SNPs in 893 European subjects with GGE - responsive or nonresponsive to lamotrigine, levetiracetam and valproic acid. Our GWAS of AED response revealed suggestive evidence for association at 29 genomic loci (p <10) but no significant association reflecting its limited power. The suggestive associations highlight candidate genes that are implicated in epileptogenesis and neurodevelopment. This first GWAS of AED response in GGE provides a comprehensive reference of SNP associations for hypothesis-driven candidate gene analyses in upcoming pharmacogenetic studies.
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http://dx.doi.org/10.2217/pgs-2019-0179DOI Listing
April 2020

Testing association of rare genetic variants with resistance to three common antiseizure medications.

Epilepsia 2020 04 6;61(4):657-666. Epub 2020 Mar 6.

Department of Applied Sciences, University of Quebec in Chicoutimi, Saguenay, Canada.

Objective: Drug resistance is a major concern in the treatment of individuals with epilepsy. No genetic markers for resistance to individual antiseizure medication (ASM) have yet been identified. We aimed to identify the role of rare genetic variants in drug resistance for three common ASMs: levetiracetam (LEV), lamotrigine (LTG), and valproic acid (VPA).

Methods: A cohort of 1622 individuals of European descent with epilepsy was deeply phenotyped and underwent whole exome sequencing (WES), comprising 575 taking LEV, 826 LTG, and 782 VPA. We performed gene- and gene set-based collapsing analyses comparing responders and nonresponders to the three drugs to determine the burden of different categories of rare genetic variants.

Results: We observed a marginally significant enrichment of rare missense, truncating, and splice region variants in individuals who were resistant to VPA compared to VPA responders for genes involved in VPA pharmacokinetics. We also found a borderline significant enrichment of truncating and splice region variants in the synaptic vesicle glycoprotein (SV2) gene family in nonresponders compared to responders to LEV. We did not see any significant enrichment using a gene-based approach.

Significance: In our pharmacogenetic study, we identified a slightly increased burden of damaging variants in gene groups related to drug kinetics or targeting in individuals presenting with drug resistance to VPA or LEV. Such variants could thus determine a genetic contribution to drug resistance.
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http://dx.doi.org/10.1111/epi.16467DOI Listing
April 2020

Fenfluramine hydrochloride for the treatment of seizures in Dravet syndrome: a randomised, double-blind, placebo-controlled trial.

Lancet 2019 12 17;394(10216):2243-2254. Epub 2019 Dec 17.

Department of Paediatric Neurology, University of Antwerp, Edegem, Belgium.

Background: Dravet syndrome is a rare, treatment-resistant developmental epileptic encephalopathy characterised by multiple types of frequent, disabling seizures. Fenfluramine has been reported to have antiseizure activity in observational studies of photosensitive epilepsy and Dravet syndrome. The aim of the present study was to assess the efficacy and safety of fenfluramine in patients with Dravet syndrome.

Methods: In this randomised, double-blind, placebo-controlled clinical trial, we enrolled children and young adults with Dravet syndrome. After a 6-week observation period to establish baseline monthly convulsive seizure frequency (MCSF; convulsive seizures were defined as hemiclonic, tonic, clonic, tonic-atonic, generalised tonic-clonic, and focal with clearly observable motor signs), patients were randomly assigned through an interactive web response system in a 1:1:1 ratio to placebo, fenfluramine 0·2 mg/kg per day, or fenfluramine 0·7 mg/kg per day, added to existing antiepileptic agents for 14 weeks. The primary outcome was the change in mean monthly frequency of convulsive seizures during the treatment period compared with baseline in the 0·7 mg/kg per day group versus placebo; 0·2 mg/kg per day versus placebo was assessed as a key secondary outcome. Analysis was by modified intention to treat. Safety analyses included all participants who received at least one dose of study medication. This trial is registered with ClinicalTrials.gov with two identical protocols NCT02682927 and NCT02826863.

Findings: Between Jan 15, 2016, and Aug 14, 2017, we assessed 173 patients, of whom 119 patients (mean age 9·0 years, 64 [54%] male) were randomly assigned to receive either fenfluramine 0·2 mg/kg per day (39), fenfluramine 0·7 mg/kg per day (40) or placebo (40). During treatment, the median reduction in seizure frequency was 74·9% in the fenfluramine 0·7 mg/kg group (from median 20·7 seizures per 28 days to 4·7 seizures per 28 days), 42·3% in the fenfluramine 0·2 mg/kg group (from median 17·5 seizures per 28 days to 12·6 per 28 days), and 19·2% in the placebo group (from median 27·3 per 28 days to 22·0 per 28 days). The study met its primary efficacy endpoint, with fenfluramine 0·7 mg/kg per day showing a 62·3% greater reduction in mean MCSF compared with placebo (95% CI 47·7-72·8, p<0·0001); fenfluramine 0·2 mg/kg per day showed a 32·4% reduction in mean MCSF compared with placebo (95% CI 6·2-52·3, p=0·0209). The most common adverse events (occurring in at least 10% of patients and more frequently in the fenfluramine groups) were decreased appetite, diarrhoea, fatigue, lethargy, somnolence, and decreased weight. Echocardiographic examinations revealed valve function within the normal physiological range in all patients during the trial and no signs of pulmonary arterial hypertension.

Interpretation: In Dravet syndrome, fenfluramine provided significantly greater reduction in convulsive seizure frequency compared with placebo and was generally well tolerated, with no observed valvular heart disease or pulmonary arterial hypertension. Fenfluramine could be an important new treatment option for patients with Dravet syndrome.

Funding: Zogenix.
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http://dx.doi.org/10.1016/S0140-6736(19)32500-0DOI Listing
December 2019

Encephalopathy with continuous spike-waves during slow-wave sleep: evolution and prognosis.

Epileptic Disord 2019 Jun;21(S1):15-21

Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Harvard Medical School, Boston Children's Hospital, Boston, USA.

Encephalopathy with continuous spike-waves during slow-wave sleep (CSWS) evolves over time, and three stages can be recognized: before the onset of CSWS, during CSWS, and after the CSWS period. Clinical seizures tend to remit spontaneously around puberty. This pattern is independent of the etiological lesion. The CSWS also disappears in all cases. Focal abnormalities instead, may persist for some time after the disappearance of CSWS. The disappearance of the clinical seizures and CSWS may be simultaneous or seizures may disappear before or after disappearance of the CSWS pattern on the EEG. Electroclinical parameters in the pre-CSWS period that have been proposed to predict a poor outcome are early-onset seizures, appearance of new seizures, and a significant increase in seizure frequency. From the electrical point of view, an increase in the frequency of the interictal EEG paroxysms while awake and during sleep and bilateral spike-and-wave paroxysms may also be predictive of a poor evolution in CSWS. When CSWS disappears, neurocognitive and behavioral status improve, but in most patients, residual moderate to severe neurocognitive impairments remain. In non-lesional epilepsy, cognitive recovery after cessation of the CSWS depends on the severity and duration of the initial regression. The duration of the CSWS seems to be the most important predictor of cognitive outcome. Early recognition and effective therapy to reduce the seizures and resolve the CSWS may be crucial to improve long-term prognosis. Cognitive recovery is observed in patients who respond well to AED treatment and outcome depends on the etiology.
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http://dx.doi.org/10.1684/epd.2019.1052DOI Listing
June 2019

Idiopathic encephalopathy related to status epilepticus during slow sleep (ESES) as a "pure" model of epileptic encephalopathy. An electroclinical, genetic, and follow-up study.

Epilepsy Behav 2019 08 26;97:244-252. Epub 2019 Jun 26.

Danish Epilepsy Centre - Filadelfia, Dianalund, Denmark; Department of Regional Health Research, University of Southern Denmark, Odense, Denmark.

Objective: The objective of the study was to investigate electroclinical and neuropsychological features, genetic background, and evolution of children with idiopathic encephalopathy with status epilepticus during slow sleep (ESES), including Landau-Kleffner syndrome (LKS).

Material And Methods: All children diagnosed with idiopathic ESES at the Danish Epilepsy Centre between March 2003 and December 2014 were retrospectively reviewed. Repeated 24-hour electroencephalography (24-h EEG) recordings, neuropsychological assessments, and clinical-neurological evaluation were performed throughout the follow-up in all patients. In 13 children, genetic investigations were performed.

Results: We collected 24 children (14 males and 10 females). Mean age at ESES diagnosis was 6 years, and mean ESES duration was 2 years and 7 months. Twenty-one children had epileptic seizures. Three children had LKS. Topography of sleep-related EEG epileptic abnormalities was diffuse in 3 subjects, hemispheric in 6, multifocal in 9, and focal in 6. During the active phase of ESES, all children presented with a heterogeneous combination of behavioral and cognitive disturbances. In 14 children, a parallel between severity of the clinical picture and spike-wave index (SWI) was observed. We could not find a strict correlation between the type and severity of neurobehavioral impairment and the side/topography of sleep-related EEG discharges during the active phase of ESES. At the last follow-up, 21 children were in remission from ESES. Complete recovery from neurobehavioral disorders was observed in 5 children. Genetic assessment, performed in 13 children, showed GRIN2A variant in two (15.4%).

Significance: Our patients with idiopathic ESES showed a heterogeneous pattern of epileptic seizures, neurobehavioral disorders, and sleep EEG features. Only one-fourth of children completely recovered from the neuropsychological disturbances after ESES remission. Lack of correlation between severity/type of cognitive derangement and SWI and/or topography of sleep EEG epileptic abnormalities may suggest the contribution of additional factors (including impaired sleep homeostasis due to epileptic activity) in the neurobehavioral derangement that characterize ESES.
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http://dx.doi.org/10.1016/j.yebeh.2019.05.030DOI Listing
August 2019

Current treatment options for Encephalopathy related to Status Epilepticus during slow Sleep.

Epileptic Disord 2019 Jun;21(S1):76-81

HUS Medical Imaging Center, Clinical Neurophysiology, University of Helsinki, Helsinki University Hospital and University of Helsinki, Finland.

The major goal of therapy in patients with Encephalopathy related to Status Epilepticus during slow Sleep (ESES) is to prevent or reduce associated cognitive deficits. Whether or not the EEG pattern of ESES should be completely suppressed to improve cognition is unknown. In clinical practice, there are two major challenges: to establish the optimal treatment strategy in patients with ESES, and to identify the patients who will benefit most from therapy, including atypical cases. Here, we provide a comprehensive overview of the current literature on treatment efficacy in patients with ESES.
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http://dx.doi.org/10.1684/epd.2019.1061DOI Listing
June 2019

Pharmacokinetic Variability and Clinical Use of Lacosamide in Children and Adolescents in Denmark and Norway.

Ther Drug Monit 2019 06;41(3):340-347

Department of Pharmacology, Oslo University Hospital, Oslo, Norway.

Background: The indication for the antiepileptic drug lacosamide (LCM) was recently extended to include children from the age of 4 years. Real-life data on the use and serum concentrations of LCM in children and adolescents are limited. The purpose of this study was to investigate the use of LCM in this patient group in relation to age, comedication, dose, serum concentrations and duration of treatment, and to examine pharmacokinetic variability.

Methods: Children and adolescents (<18 years) who had serum concentrations of LCM measured from January 2012 to June 2018 were retrospectively identified from the therapeutic drug monitoring databases at 2 national epilepsy centers in Norway and Denmark. Clinical data were collected from request forms and medical records.

Results: Data from 124 patients were included, 61 girls/63 boys. Weight was available for 76 patients. Median age was 15 years (range 2-17 years), dose of LCM 300 mg/d (76-600 mg/d), and serum concentration 18 µmol/L (5-138 µmol/L) [4.5 mg/L (1.3-34.5 mg/L)]. Pharmacokinetic variability was demonstrated as the concentration/(dose/kg) ratio ranged from 1.3 to 9.4 (µmol/L)/(mg/kg) and was affected by age. Polytherapy with 1-3 other antiepileptic drugs was noted in 107 patients (86%). Treatment was continued beyond 1 year in 71% (n = 45) of the 63 patients where such information was available, and all of these 45 patients had serum concentrations within the defined reference range. The 1-year retention rate was higher in patients not concomitantly using other sodium channel-blocking drugs (82% versus 56%).

Conclusions: The study demonstrates pharmacokinetic variability in and between age groups, which indicates usefulness of therapeutic drug monitoring. More than two-thirds of patients continued treatment beyond 1 year, suggesting reasonable effectiveness.
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http://dx.doi.org/10.1097/FTD.0000000000000599DOI Listing
June 2019

Rare coding variants in genes encoding GABA receptors in genetic generalised epilepsies: an exome-based case-control study.

Lancet Neurol 2018 08 17;17(8):699-708. Epub 2018 Jul 17.

Background: Genetic generalised epilepsy is the most common type of inherited epilepsy. Despite a high concordance rate of 80% in monozygotic twins, the genetic background is still poorly understood. We aimed to investigate the burden of rare genetic variants in genetic generalised epilepsy.

Methods: For this exome-based case-control study, we used three different genetic generalised epilepsy case cohorts and three independent control cohorts, all of European descent. Cases included in the study were clinically evaluated for genetic generalised epilepsy. Whole-exome sequencing was done for the discovery case cohort, a validation case cohort, and two independent control cohorts. The replication case cohort underwent targeted next-generation sequencing of the 19 known genes encoding subunits of GABA receptors and was compared to the respective GABA receptor variants of a third independent control cohort. Functional investigations were done with automated two-microelectrode voltage clamping in Xenopus laevis oocytes.

Findings: Statistical comparison of 152 familial index cases with genetic generalised epilepsy in the discovery cohort to 549 ethnically matched controls suggested an enrichment of rare missense (Nonsyn) variants in the ensemble of 19 genes encoding GABA receptors in cases (odds ratio [OR] 2·40 [95% CI 1·41-4·10]; p=0·0014, adjusted p=0·019). Enrichment for these genes was validated in a whole-exome sequencing cohort of 357 sporadic and familial genetic generalised epilepsy cases and 1485 independent controls (OR 1·46 [95% CI 1·05-2·03]; p=0·0081, adjusted p=0·016). Comparison of genes encoding GABA receptors in the independent replication cohort of 583 familial and sporadic genetic generalised epilepsy index cases, based on candidate-gene panel sequencing, with a third independent control cohort of 635 controls confirmed the overall enrichment of rare missense variants for 15 GABA receptor genes in cases compared with controls (OR 1·46 [95% CI 1·02-2·08]; p=0·013, adjusted p=0·027). Functional studies for two selected genes (GABRB2 and GABRA5) showed significant loss-of-function effects with reduced current amplitudes in four of seven tested variants compared with wild-type receptors.

Interpretation: Functionally relevant variants in genes encoding GABA receptor subunits constitute a significant risk factor for genetic generalised epilepsy. Examination of the role of specific gene groups and pathways can disentangle the complex genetic architecture of genetic generalised epilepsy.

Funding: EuroEPINOMICS (European Science Foundation through national funding organisations), Epicure and EpiPGX (Sixth Framework Programme and Seventh Framework Programme of the European Commission), Research Unit FOR2715 (German Research Foundation and Luxembourg National Research Fund).
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http://dx.doi.org/10.1016/S1474-4422(18)30215-1DOI Listing
August 2018

Specific Patient Features Affect Antiepileptic Drug Therapy Decisions: Focus on Gender, Age, and Psychiatric Comorbidities.

Curr Pharm Des 2017 ;23(37):5639-5648

Department of Clinical and Experimental Medicine, University of Messina, Italy.

Background: Patient features, apart from the type of seizures/epilepsy, affect markedly antiepileptic drug (AED) choice and dosage. The present review focuses on gender, age and psychiatric comorbidities which play a leading role in influencing antiepileptic treatment.

Methods: Reviews with large population of patients, controlled clinical trials, observational investigations, experimental studies and experimental reviews of experimental data, where appropriated, were analysed and illustrated to produce the most homogeneous indications possible. Different and also contradictory observations have been highlighted to stimulate a critical approach to specific aspects.

Results: Women of childbearing age should avoid valproic (VPA), acid, since this drug doubles the risk of major malformations and causes in the exposed offspring reduced intellectual development and disorders of autistic spectrum. The drug is also associated with hormonal disorders, polycystic ovary and reduced fertility. Children treated with valproic acid or phenobarbital can exhibit hyperactivity, nervousness and attention disorders. As a consequence of increased drug elimination, younger children require higher doses as compared to adults and older patients. Elderly patients treated with phenobarbital may face the risk of cognitive disorders and/or falls resulting in bone fractures. Fractures are also facilitated by carbamazepine-induced osteoporosis. Psychiatric disorders are frequently associated with epilepsy and evidence has been gained that common pathological steps underlie these conditions. Depressed patients should avoid drugs like phenobarbital, topiramate, levetiracetam, zonisamide and perampanel since these drugs can induce mood disorders. Although not conclusive, literature data indicate that topiramate and levetiracetam and also tiagabine and vigabatrin, are associated with suicidal thought/behaviour. Conversely, lamotrigine, carbamazepine, VPA and oxcarbazepine exert beneficial effects on mood. Bupropion, clomipramine, amoxapine and maprotyline among antidepressants, and clozapine, olanzapine and quietapine among antipsychotics have been observed to lower seizure threshold. Serum AED concentration monitoring is of help in dosage adjustments, especially in very young children, in patients with cognitive decline and in patients with psychiatric comorbidities.

Conclusions: A careful evaluation of the patient variables analysed in the present review is useful to personalize and optimize AED therapy.
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http://dx.doi.org/10.2174/1381612823666170926103631DOI Listing
July 2019

Real-world data on rufinamide treatment in patients with Lennox-Gastaut syndrome: Results from a European noninterventional registry study.

Epilepsy Behav 2017 11 15;76:63-70. Epub 2017 Sep 15.

Eisai Europe Ltd, European Knowledge Centre, Mosquito Way, Hatfield, Hertfordshire AL10 9SN, UK.

Introduction: Rufinamide is approved for the adjunctive treatment of seizures associated with Lennox-Gastaut syndrome (LGS) in patients aged ≥4years. The objective of this study was to provide real-world, long-term data on patients with LGS initiating rufinamide as add-on therapy and patients with LGS receiving other antiepileptic drugs (AEDs).

Methods: A Phase IV, noninterventional, multicenter registry study was conducted in patients with LGS aged ≥4years requiring modification to any AED treatment, including initiation of add-on rufinamide therapy. Safety/tolerability was assessed by evaluating treatment-emergent adverse events (TEAEs), and efficacy was assessed using a generic seizure frequency scale.

Results: A total of 111 patients from 64 sites in 8 European countries were included, of whom 64 initiated rufinamide ("rufinamide" group) and 21 did not receive rufinamide at any time during the study ("no-rufinamide" group). Mean ages were 16.1years (rufinamide) and 15.0years (no rufinamide). The median duration of follow-up was >2years (range: 1.3-46.4months). Antiepileptic drug-related TEAEs were reported for 40.6% (rufinamide) and 33.3% (no rufinamide) of patients and led to discontinuation of 7.8% and 4.8%, respectively. The most frequently reported rufinamide-related TEAEs (≥5% patients) were somnolence (7.8%) and decreased appetite (6.3%). There were no unexpected safety/tolerability findings. At month 12, the proportion of patients with improvement in all seizures ("much improved" or "very much improved") was 28.6% (12/42) for the rufinamide group and 14.3% (2/14) for the no-rufinamide group.

Conclusion: The study provided valuable information on LGS and its management, and evidence that rufinamide has a consistent and generally favorable safety/tolerability profile when used in routine clinical practice. CLINICALTRIALS.

Gov Identifier: NCT01991041.
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http://dx.doi.org/10.1016/j.yebeh.2017.08.026DOI Listing
November 2017

Alternating hemiplegia of childhood and a pathogenic variant of ATP1A3: a case report and pathophysiological considerations.

Epileptic Disord 2017 Jun;19(2):226-230

Danish Epilepsy Centre - Epilepsihospitalet Filadelfia / University of Copenhagen, Dianalund, Denmark, IRCCS Institute of Neurological Sciences, Bellaria Hospital, Bologna, Italy.

We describe a case of a child suffering from alternating hemiplegia with a heterozygous p. E815K pathogenic variant of ATP1A3. The patient started to present abnormal eye movements in the first days of life, followed by the appearance at 2 months of dystonic episodes, and later on, by recurrent episodes of alternating hemiplegia more often on the right side. A severe epilepsy started at the age of 2 years with episodes of status epilepticus since the onset which frequently recurred, requiring admission to the intensive care unit. MRI showed bilateral mesial temporal sclerosis and a left-sided ischaemic lesion. Interictal EEG showed bilateral abnormalities, whereas postictal EEG after status epilepticus showed overt slowing on the left side, suggesting a predominant involvement of ictal activity of the left hemisphere. We hypothesize that in our patient, the left hemisphere might have been more prominently affected by the pathogenetic abnormalities underlying alternating hemiplegia of childhood, rendering it more prone to early ischaemic lesions and recurrent unilateral status epilepticus. We speculate whether alternating hemiplegia of childhood shares some common pathophysiological mechanisms with familial hemiplegic migraine that may be associated with a pathogenic variant of ATP1A2.
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http://dx.doi.org/10.1684/epd.2017.0913DOI Listing
June 2017

Genetic and phenotypic heterogeneity suggest therapeutic implications in SCN2A-related disorders.

Brain 2017 May;140(5):1316-1336

CeGaT - Center for Genomics and Transcriptomics, Tübingen, Germany.

Mutations in SCN2A, a gene encoding the voltage-gated sodium channel Nav1.2, have been associated with a spectrum of epilepsies and neurodevelopmental disorders. Here, we report the phenotypes of 71 patients and review 130 previously reported patients. We found that (i) encephalopathies with infantile/childhood onset epilepsies (≥3 months of age) occur almost as often as those with an early infantile onset (<3 months), and are thus more frequent than previously reported; (ii) distinct phenotypes can be seen within the late onset group, including myoclonic-atonic epilepsy (two patients), Lennox-Gastaut not emerging from West syndrome (two patients), and focal epilepsies with an electrical status epilepticus during slow sleep-like EEG pattern (six patients); and (iii) West syndrome constitutes a common phenotype with a major recurring mutation (p.Arg853Gln: two new and four previously reported children). Other known phenotypes include Ohtahara syndrome, epilepsy of infancy with migrating focal seizures, and intellectual disability or autism without epilepsy. To assess the response to antiepileptic therapy, we retrospectively reviewed the treatment regimen and the course of the epilepsy in 66 patients for which well-documented medical information was available. We find that the use of sodium channel blockers was often associated with clinically relevant seizure reduction or seizure freedom in children with early infantile epilepsies (<3 months), whereas other antiepileptic drugs were less effective. In contrast, sodium channel blockers were rarely effective in epilepsies with later onset (≥3 months) and sometimes induced seizure worsening. Regarding the genetic findings, truncating mutations were exclusively seen in patients with late onset epilepsies and lack of response to sodium channel blockers. Functional characterization of four selected missense mutations using whole cell patch-clamping in tsA201 cells-together with data from the literature-suggest that mutations associated with early infantile epilepsy result in increased sodium channel activity with gain-of-function, characterized by slowing of fast inactivation, acceleration of its recovery or increased persistent sodium current. Further, a good response to sodium channel blockers clinically was found to be associated with a relatively small gain-of-function. In contrast, mutations in patients with late-onset forms and an insufficient response to sodium channel blockers were associated with loss-of-function effects, including a depolarizing shift of voltage-dependent activation or a hyperpolarizing shift of channel availability (steady-state inactivation). Our clinical and experimental data suggest a correlation between age at disease onset, response to sodium channel blockers and the functional properties of mutations in children with SCN2A-related epilepsy.
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http://dx.doi.org/10.1093/brain/awx054DOI Listing
May 2017

Mutations in GABRB3: From febrile seizures to epileptic encephalopathies.

Neurology 2017 01 4;88(5):483-492. Epub 2017 Jan 4.

From the Danish Epilepsy Centre (R.S.M., K.M.J., M.N.), Dianalund; Institute for Regional Health Services (R.S.M., K.M.J., M.N.), University of Southern Denmark, Odense; Department of Neurology and Epileptology (T.V.W., S.V., H.L., S.M.), Hertie Institute for Clinical Brain Research, and Department of Neurosurgery (T.V.W.), University of Tübingen; Department of Neuropediatrics (I.H., M.P., S.v.S., H.M.), University Medical Center Schleswig-Holstein, Kiel, Germany; Division of Neurology (I.H., S.H., H.D.), The Children's Hospital of Philadelphia, PA; Neuroscience Department (C.M., R.G.), Children's Hospital Anna Meyer-University of Florence, Italy; Department of Genetics (E.H.B., M.S., K.L.v.G.), University Medical Center Utrecht, the Netherlands; Department of Neurology and Neurorehabilitation (U.V., I.T., T.T.), Children's Clinic of Tartu University Hospital, Estonia; Department of Pediatric Neurology and Epilepsy Center (I.B.), LMU Munich, Germany; Department of Pediatrics (I.T., T.T.), University of Tartu; Tallinn Children's Hospital (I.T.), Tallinn, Estonia; Clinic for Neuropediatrics and Neurorehabilitation (G.K., C.B., H.H.), Epilepsy Center for Children and Adolescents, Schön Klinik Vogtareuth, Germany; Paracelsus Medical Private University (G.K.), Salzburg, Austria; Neuropeadiatric Department (L.L.F.), Hospices Civils de Lyon; Department of Genetics (G.L., N.C.), Lyon University Hospitals; Claude Bernard Lyon I University (G.L., N.C.); Lyon Neuroscience Research Centre (G.L., N.C.), CNRS UMR5292, INSERM U1028; Epilepsy, Sleep and Pediatric Neurophysiology Department (J.d.B.), Lyon University Hospitals, France; Clinic for Pediatric Neurology (S.B.), Pediatric Department, University Hospital, Herlev, Denmark; Kleinwachau (N.H.), Sächsisches Epilepsiezentrum Radeberg, Dresden; Department of Neuropediatrics/Epilepsy Center (J.J.), University Medical Center Freiburg; Department of General Paediatrics (S.S.), Division of Child Neurology and Inherited Metabolic Diseases, Centre for Paediatrics and Adolescent Medicine, University Hospital Heidelberg; Department of Women and Child Health (S.S.), Hospital for Children and Adolescents, University of Leipzig Hospitals and Clinics, Germany; Department of Pediatrics (C.T.M., H.C.M.), Division of Genetic Medicine, University of Washington, Seattle; Amplexa Genetics (L.H.G.L., H.A.D.), Odense, Denmark; Northern German Epilepsy Center for Children and Adolescents (S.v.S.), Schwentinental-Raisdorf, Germany; Wilhelm Johannsen Centre for Functional Genome Research (Y.M., N.T.), Department of Cellular and Molecular Medicine, University of Copenhagen; Danish Epilepsy Center (G.R.), Filadelfia/University of Copenhagen, Denmark; Department of Diagnostics (J.R.L.), Institute of Human Genetics, University of Leipzig; and Svt. Luka's Institute of Child Neurology and Epilepsy (K.M.), Moscow, Russia. Dr Maljevic is currently at the Florey Institute of Neuroscience and Mental Health, Melbourne, Australia.

Objective: To examine the role of mutations in GABRB3 encoding the β subunit of the GABA receptor in individual patients with epilepsy with regard to causality, the spectrum of genetic variants, their pathophysiology, and associated phenotypes.

Methods: We performed massive parallel sequencing of GABRB3 in 416 patients with a range of epileptic encephalopathies and childhood-onset epilepsies and recruited additional patients with epilepsy with GABRB3 mutations from other research and diagnostic programs.

Results: We identified 22 patients with heterozygous mutations in GABRB3, including 3 probands from multiplex families. The phenotypic spectrum of the mutation carriers ranged from simple febrile seizures, genetic epilepsies with febrile seizures plus, and epilepsy with myoclonic-atonic seizures to West syndrome and other types of severe, early-onset epileptic encephalopathies. Electrophysiologic analysis of 7 mutations in Xenopus laevis oocytes, using coexpression of wild-type or mutant β, together with α and γ subunits and an automated 2-microelectrode voltage-clamp system, revealed reduced GABA-induced current amplitudes or GABA sensitivity for 5 of 7 mutations.

Conclusions: Our results indicate that GABRB3 mutations are associated with a broad phenotypic spectrum of epilepsies and that reduced receptor function causing GABAergic disinhibition represents the relevant disease mechanism.
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http://dx.doi.org/10.1212/WNL.0000000000003565DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5278942PMC
January 2017

Gene Panel Testing in Epileptic Encephalopathies and Familial Epilepsies.

Mol Syndromol 2016 Sep 20;7(4):210-219. Epub 2016 Aug 20.

Danish Epilepsy Centre, Filadelfia, Dianalund, Denmark.

In recent years, several genes have been causally associated with epilepsy. However, making a genetic diagnosis in a patient can still be difficult, since extensive phenotypic and genetic heterogeneity has been observed in many monogenic epilepsies. This study aimed to analyze the genetic basis of a wide spectrum of epilepsies with age of onset spanning from the neonatal period to adulthood. A gene panel targeting 46 epilepsy genes was used on a cohort of 216 patients consecutively referred for panel testing. The patients had a range of different epilepsies from benign neonatal seizures to epileptic encephalopathies (EEs). Potentially causative variants were evaluated by literature and database searches, submitted to bioinformatic prediction algorithms, and validated by Sanger sequencing. If possible, parents were included for segregation analysis. We identified a presumed disease-causing variant in 49 (23%) of the 216 patients. The variants were found in 19 different genes including and . Patients with neonatal-onset epilepsies had the highest rate of positive findings (57%). The overall yield for patients with EEs was 32%, compared to 17% among patients with generalized epilepsies and 16% in patients with focal or multifocal epilepsies. By the use of a gene panel consisting of 46 epilepsy genes, we were able to find a disease-causing genetic variation in 23% of the analyzed patients. The highest yield was found among patients with neonatal-onset epilepsies and EEs.
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http://dx.doi.org/10.1159/000448369DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5073625PMC
September 2016

Review of clinical studies of perampanel in adolescent patients.

Brain Behav 2016 Sep 28;6(9):e00505. Epub 2016 Jun 28.

Eisai Pharmaceuticals India Pvt., Ltd. Mumbai India.

Aim: To assess the clinical trial and real-world data for adjunctive perampanel in adolescents and develop consensus recommendations to guide the use of perampanel in this population in clinical practice.

Methods: In May 2015, 15 epilepsy experts attended a Consensus Development Meeting to assess the clinical trial data for perampanel, specific to the adolescent age group (12-17 years) and develop consensus treatment recommendations.

Results And Discussion: Analysis of the adolescent subgroup data of three pivotal placebo-controlled, double-blind, phase 3 trials investigating perampanel in patients with ongoing focal epileptic seizures despite receiving one to three antiepileptic drugs found that perampanel 4-12 mg was superior to placebo. The tolerability profile of perampanel was generally acceptable. Adolescent patients receiving long-term treatment with perampanel in an open-label extension study maintained improvements in seizure control compared with baseline, with a favorable risk-benefit profile. A phase 2 study showed that perampanel had no clinically important effects on cognitive function, growth, and development.

Conclusion: Perampanel is a welcome addition to the armamentarium of existing antiepileptic drugs as it represents a new approach in the management of epilepsy, with a novel mechanism of action, and the potential to have a considerable impact on the treatment of adolescents with epilepsy.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5036429PMC
http://dx.doi.org/10.1002/brb3.505DOI Listing
September 2016

STXBP1 encephalopathy: A neurodevelopmental disorder including epilepsy.

Neurology 2016 Mar 10;86(10):954-62. Epub 2016 Feb 10.

Authors' affiliations are listed at the end of the article.

Objective: To give a comprehensive overview of the phenotypic and genetic spectrum of STXBP1 encephalopathy (STXBP1-E) by systematically reviewing newly diagnosed and previously reported patients.

Methods: We recruited newly diagnosed patients with STXBP1 mutations through an international network of clinicians and geneticists. Furthermore, we performed a systematic literature search to review the phenotypes of all previously reported patients.

Results: We describe the phenotypic features of 147 patients with STXBP1-E including 45 previously unreported patients with 33 novel STXBP1 mutations. All patients have intellectual disability (ID), which is mostly severe to profound (88%). Ninety-five percent of patients have epilepsy. While one-third of patients presented with Ohtahara syndrome (21%) or West syndrome (9.5%), the majority has a nonsyndromic early-onset epilepsy and encephalopathy (53%) with epileptic spasms or tonic seizures as main seizure type. We found no correlation between severity of seizures and severity of ID or between mutation type and seizure characteristics or cognitive outcome. Neurologic comorbidities including autistic features and movement disorders are frequent. We also report 2 previously unreported adult patients with prominent extrapyramidal features.

Conclusion: De novo STXBP1 mutations are among the most frequent causes of epilepsy and encephalopathy. Most patients have severe to profound ID with little correlation among seizure onset, seizure severity, and the degree of ID. Accordingly, we hypothesize that seizure severity and ID present 2 independent dimensions of the STXBP1-E phenotype. STXBP1-E may be conceptualized as a complex neurodevelopmental disorder rather than a primary epileptic encephalopathy.
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http://dx.doi.org/10.1212/WNL.0000000000002457DOI Listing
March 2016

Effectiveness of antiepileptic therapy in patients with PCDH19 mutations.

Seizure 2016 Feb 6;35:106-10. Epub 2016 Jan 6.

Kinderklinik, Stauferklinik, Schwäbisch Gmünd, Germany.

Purpose: PCDH19 mutations cause epilepsy and mental retardation limited to females (EFMR) or Dravet-like syndromes. Especially in the first years of life, epilepsy is known to be highly pharmacoresistant. The aim of our study was to evaluate the effectiveness of antiepileptic therapy in patients with PCDH19 mutations.

Methods: We report a retrospective multicenter study of antiepileptic therapy in 58 female patients with PCDH19 mutations and epilepsy aged 2-27 years (mean age 10.6 years).

Results: The most effective drugs after 3 months were clobazam and bromide, with a responder rate of 68% and 67%, respectively, where response was defined as seizure reduction of at least 50%. Defining long-term response as the proportion of responders after 12 months of treatment with a given drug in relation to the number of patients treated for at least 3 months, the most effective drugs after 12 months were again bromide and clobazam, with a long-term response of 50% and 43%, respectively. Seventy-four percent of the patients became seizure-free for at least 3 months, 47% for at least one year.

Significance: The most effective drugs in patients with PCDH19 mutations were bromide and clobazam. Although epilepsy in PCDH19 mutations is often pharmacoresistant, three quarters of the patients became seizure-free for at least for 3 months and half of them for at least one year. However, assessing the effectiveness of the drugs is difficult because a possible age-dependent spontaneous seizure remission must be considered.
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http://dx.doi.org/10.1016/j.seizure.2016.01.006DOI Listing
February 2016

The role of SLC2A1 mutations in myoclonic astatic epilepsy and absence epilepsy, and the estimated frequency of GLUT1 deficiency syndrome.

Epilepsia 2015 Dec 5;56(12):e203-8. Epub 2015 Nov 5.

Danish Epilepsy Center, Dianalund, Denmark.

The first mutations identified in SLC2A1, encoding the glucose transporter type 1 (GLUT1) protein of the blood-brain barrier, were associated with severe epileptic encephalopathy. Recently, dominant SLC2A1 mutations were found in rare autosomal dominant families with various forms of epilepsy including early onset absence epilepsy (EOAE), myoclonic astatic epilepsy (MAE), and genetic generalized epilepsy (GGE). Our study aimed to investigate the possible role of SLC2A1 in various forms of epilepsy including MAE and absence epilepsy with early onset. We also aimed to estimate the frequency of GLUT1 deficiency syndrome in the Danish population. One hundred twenty patients with MAE, 50 patients with absence epilepsy, and 37 patients with unselected epilepsies, intellectual disability (ID), and/or various movement disorders were screened for mutations in SLC2A1. Mutations in SLC2A1 were detected in 5 (10%) of 50 patients with absence epilepsy, and in one (2.7%) of 37 patient with unselected epilepsies, ID, and/or various movement disorders. None of the 120 MAE patients harbored SLC2A1 mutations. We estimated the frequency of SLC2A1 mutations in the Danish population to be approximately 1:83,000. Our study confirmed the role of SLC2A1 mutations in absence epilepsy with early onset. However, our study failed to support the notion that SLC2A1 aberrations are a cause of MAE without associated features such as movement disorders.
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http://dx.doi.org/10.1111/epi.13222DOI Listing
December 2015

Encephalopathy with status epilepticus during sleep (ESES) induced by oxcarbazepine in idiopathic focal epilepsy in childhood.

Funct Neurol 2015 Apr-Jun;30(2):139-41

Encephalopathy with status epilepticus during sleep (ESES) is an age-related disorder characterized by neuropsychological regression, epilepsy and a typical EEG pattern of continuous epileptiform activity (> 85%) during NREM sleep. Cases of worsening or induction of ESES with phenytoin, carbamazepine and phenobarbital have been reported. We describe a child with benign epilepsy with centrotemporal spikes (BECTS) in whom treatment with oxcarbazepine (OXC) induced ESES. The patient was studied through repeated clinical-neuropsychological evaluations and 24-hour EEG recordings. He was treated with OXC two months after epilepsy onset. One month after starting OXC, he developed an abrupt and severe cognitive deterioration. A 24-hour EEG and neuropsychological tests showed an electroclinical picture compatible with ESES. Withdrawal of OXC and introduction of other drugs were followed by a prompt improvement. Five months after ESES onset, a 24-hour EEG was normal. Our report indicates that OXC can induce ESES in BECTS.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4610762PMC
http://dx.doi.org/10.11138/fneur/2015.30.2.139DOI Listing
June 2016

Mutations in KCNT1 cause a spectrum of focal epilepsies.

Epilepsia 2015 Sep 30;56(9):e114-20. Epub 2015 Jun 30.

Department of Pediatrics, Aarhus University Hospital, Aarhus, Denmark.

Autosomal dominant mutations in the sodium-gated potassium channel subunit gene KCNT1 have been associated with two distinct seizure syndromes, nocturnal frontal lobe epilepsy (NFLE) and malignant migrating focal seizures of infancy (MMFSI). To further explore the phenotypic spectrum associated with KCNT1, we examined individuals affected with focal epilepsy or an epileptic encephalopathy for mutations in the gene. We identified KCNT1 mutations in 12 previously unreported patients with focal epilepsy, multifocal epilepsy, cardiac arrhythmia, and in a family with sudden unexpected death in epilepsy (SUDEP), in addition to patients with NFLE and MMFSI. In contrast to the 100% penetrance so far reported for KCNT1 mutations, we observed incomplete penetrance. It is notable that we report that the one KCNT1 mutation, p.Arg398Gln, can lead to either of the two distinct phenotypes, ADNFLE or MMFSI, even within the same family. This indicates that genotype-phenotype relationships for KCNT1 mutations are not straightforward. We demonstrate that KCNT1 mutations are highly pleiotropic and are associated with phenotypes other than ADNFLE and MMFSI. KCNT1 mutations are now associated with Ohtahara syndrome, MMFSI, and nocturnal focal epilepsy. They may also be associated with multifocal epilepsy and cardiac disturbances.
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http://dx.doi.org/10.1111/epi.13071DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5915334PMC
September 2015

Mutations in the GABA Transporter SLC6A1 Cause Epilepsy with Myoclonic-Atonic Seizures.

Am J Hum Genet 2015 May 9;96(5):808-15. Epub 2015 Apr 9.

Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, WA 98195, USA. Electronic address:

GAT-1, encoded by SLC6A1, is one of the major gamma-aminobutyric acid (GABA) transporters in the brain and is responsible for re-uptake of GABA from the synapse. In this study, targeted resequencing of 644 individuals with epileptic encephalopathies led to the identification of six SLC6A1 mutations in seven individuals, all of whom have epilepsy with myoclonic-atonic seizures (MAE). We describe two truncations and four missense alterations, all of which most likely lead to loss of function of GAT-1 and thus reduced GABA re-uptake from the synapse. These individuals share many of the electrophysiological properties of Gat1-deficient mice, including spontaneous spike-wave discharges. Overall, pathogenic mutations occurred in 6/160 individuals with MAE, accounting for ~4% of unsolved MAE cases.
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http://dx.doi.org/10.1016/j.ajhg.2015.02.016DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4570550PMC
May 2015

Effectiveness and tolerability of perampanel in children and adolescents with refractory epilepsies: first experiences.

Neuropediatrics 2015 Apr 2;46(2):110-6. Epub 2015 Mar 2.

Department of Pediatric Neurology and Neurological Rehabilitation, Schön Klinik Vogtareuth, Vogtareuth, Germany.

Objective: This article aims to report the first clinical experiences concerning effectiveness and tolerability of perampanel (PER) in a pediatric population with refractory epilepsies.

Patients And Methods: This nonsponsored, observational, retrospective survey was conducted through collaboration with multiple centers in Europe. The clinical course of the first pediatric patients treated in these centers with PER was documented with the help of a questionnaire completed by the treating physicians. Effectiveness and adverse effects were evaluated. The study population consisted of 58 patients (mean age, 10.5 years; range, 2-17 years), suffering from various refractory epilepsies, classified as focal epilepsy (n = 36), unclassified generalized epilepsy (n = 12), Lennox-Gastaut syndrome (n = 5), West syndrome (n = 3), and Dravet syndrome (n = 2).

Results: The response rate (≥ 50% seizure reduction) after the first 3 months of therapy was 31% (18/58 patients) in total. Complete seizure control was achieved in five patients (9% overall). Aggravation of seizures occurred in five cases (9%). The most frequently occurring adverse effects were reduced vigilance or fatigue (n = 16) and behavioral changes (n = 14).

Discussion: PER seems to be effective also in children and adolescents with pharmaco-refractory epilepsies. Tolerability was acceptable.
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http://dx.doi.org/10.1055/s-0035-1546276DOI Listing
April 2015

Current role of rufinamide in the treatment of childhood epilepsy: literature review and treatment guidelines.

Eur J Paediatr Neurol 2014 Nov 28;18(6):685-90. Epub 2014 May 28.

Department of Systems Medicine, Child Neurology and Psychiatry Unit, Tor Vergata University Hospital of Rome, Italy. Electronic address:

Purpose: The literature on the efficacy and safety of rufinamide in childhood-onset epilepsy syndromes currently includes approximately 600 paediatric patients. This paper summarizes the views of a panel of experienced European epileptologists with regard to the current role of rufinamide in the treatment of childhood epilepsies.

Results: Rufinamide is effective in decreasing the seizure frequency in the Lennox-Gastaut syndrome (LGS), especially tonic and atonic seizures. It might consequently be preferred to other drugs as a second-line treatment for LGS when drop-attacks are frequent. The mean responder rate in the published studies is 38% with seizure freedom achieved in 2.4% of patients. Rufinamide has shown some efficacy in epileptic encephalopathies other than LGS. It can be also effective as adjunctive therapy in children and adolescents with drug-resistant partial seizures. The available data suggest that rufinamide has an acceptable risk/benefit ratio with quite a low risk of aggravating seizures. Common adverse effects (somnolence, nausea and vomiting) are usually mild and self-limiting; they are more frequently observed during titration than in the maintenance phase, suggesting that low escalation rates might be associated with fewer adverse effects. Rufinamide appears to have a favourable cognitive profile compared with other antiepileptic drugs.

Conclusion: Rufinamide is only approved for adjunctive treatment of seizures associated with LGS in children 4 years of age and older. There are very few data on rufinamide treatment at the onset of LGS or early in the course of the disorder; whether early treatment will improve outcome has yet to be determined.
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http://dx.doi.org/10.1016/j.ejpn.2014.05.008DOI Listing
November 2014

GABRA1 and STXBP1: novel genetic causes of Dravet syndrome.

Neurology 2014 Apr 12;82(14):1245-53. Epub 2014 Mar 12.

From the Division of Genetic Medicine, Department of Pediatrics (G.L.C., C.H., J.C., E.G., H.C.M.), and the Department of Genome Sciences (J.S.), University of Washington, Seattle; Neurogenetics Group (S.W.), Department of Molecular Genetics, VIB, Antwerp; Laboratory of Neurogenetics (S.W., A.S., P.D.J.), Institute Born-Bunge, University of Antwerp, Belgium; Epilepsy Centre Kempenhaeghe (S.W.), Oosterhout, the Netherlands; Epilepsy Research Centre (J.M.M., S.F.B., I.E.S.), Department of Medicine, University of Melbourne, Austin Health, Australia; Department of Neuropediatrics (C.H., H.M., S.v.S., I.H.), University Medical Center, Schleswig-Holstein, Christian-Albrechts University, Kiel, Germany; Danish Epilepsy Centre (R.S.M., H.H., M.N.), Dianalund; Institute for Regional Health Services (H.H., M.N.), University of Southern Denmark, Odense, Denmark; Department of Molecular and Medical Genetics (B.J.O.), Oregon Health and Science University, Portland; Florey Institute (S.P., A.C., E.V.G., I.E.S.), Victoria; TY Nelson Department of Neurology (D.G.), The Children's Hospital at Westmead, Sydney, NSW, Australia; Department of Paediatrics (L.G.S.), School of Medicine and Health Sciences, University of Otago, Wellington, New Zealand; Epilepsy Research Program (B.L.H., L.M.D.), School of Pharmacy and Medical Sciences, University of South Australia, Adelaide; Division of Neurology (P.D.J.), Antwerp University Hospital, Belgium; and the Department of Paediatrics (I.E.S.), University of Melbourne, Royal Children's Hospital, Australia.

Objective: To determine the genes underlying Dravet syndrome in patients who do not have an SCN1A mutation on routine testing.

Methods: We performed whole-exome sequencing in 13 SCN1A-negative patients with Dravet syndrome and targeted resequencing in 67 additional patients to identify new genes for this disorder.

Results: We detected disease-causing mutations in 2 novel genes for Dravet syndrome, with mutations in GABRA1 in 4 cases and STXBP1 in 3. Furthermore, we identified 3 patients with previously undetected SCN1A mutations, suggesting that SCN1A mutations occur in even more than the currently accepted ∼ 75% of cases.

Conclusions: We show that GABRA1 and STXBP1 make a significant contribution to Dravet syndrome after SCN1A abnormalities have been excluded. Our results have important implications for diagnostic testing, clinical management, and genetic counseling of patients with this devastating disorder and their families.
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http://dx.doi.org/10.1212/WNL.0000000000000291DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4001207PMC
April 2014

Efficacy of verapamil as an adjunctive treatment in children with drug-resistant epilepsy: a pilot study.

Seizure 2014 Jan 23;23(1):36-40. Epub 2013 Sep 23.

NESMOS Department, Chair of Pediatrics, Child Neurology, Faculty of Medicine and Psychology, "Sapienza" University of Rome, Italy.

Purpose: Verapamil, a voltage-gated calcium channel blocker, has been occasionally reported to have some effect on reducing seizure frequency in drug-resistant epilepsy or status epilepticus. We aimed to investigate the efficacy of verapamil as add-on treatment in children with drug-resistant epilepsy.

Methods: Seven children with drug-resistant structural-metabolic, unknown or genetic (e.g., Dravet syndrome [DS]) epilepsy received verapamil as an add-on drug to baseline antiepileptic therapy. Verapamil was slowly introduced at the dosage of 1mg/kg/day and titrated up to 1.5mg/kg/day. After completing the titration period, patients entered a 14-month maintenance period and were followed up at 3, 8, and 14 months. Heart monitoring was performed at baseline and at each follow-up. The primary outcome measure was the response of seizures to verapamil.

Results: Three subjects with genetically determined DS showed a partial (reduction of 50-99%) response for all types of seizures. A patient with DS without known mutation showed a partial control of all types of seizures in the first 13 months; then seizures worsened and verapamil was suspended. Two patients with structural epilepsy and one with Lennox-Gastaut syndrome showed no improvement. Any side effects were recorded.

Conclusions: Add-on treatment with verapamil seems to have some effect in controlling seizures in patients with genetically determined DS. Our observations justify further research on the relationship between calcium channels, calcium channel blockers, and channelopathies.
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http://dx.doi.org/10.1016/j.seizure.2013.09.009DOI Listing
January 2014

A balanced translocation disrupts SYNGAP1 in a patient with intellectual disability, speech impairment, and epilepsy with myoclonic absences (EMA).

Epilepsia 2011 Dec 2;52(12):e190-3. Epub 2011 Nov 2.

Danish Epilepsy Center, Dianalund, Denmark.

Epilepsy with myoclonic absences (EMA) is a rare form of generalized epilepsy occurring in childhood and is often difficult to treat. The underlying etiology of EMA is unknown in the majority of patients. Herein, we describe a patient with EMA and intellectual disability who carries a de novo balanced translocation: t(6;22)(p21.32;q11.21). We mapped the translocation breakpoints by fluorescence in situ hybridization (FISH), and the breakpoint at 6p21.32 was found to truncate the N-methyl-d-aspartate (NMDA)-receptor associated gene SYNGAP1. The breakpoint at 22q11.21 was within a highly variable region without known protein-coding genes. Mutations of SYNGAP1 are associated with nonsyndromal intellectual disability (NSID). Two-thirds of the patients described so far also have generalized epilepsy. This finding, together with our report, suggests that dysfunction of SYNGAP1 contributes to the development of generalized epilepsy, including EMA.
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http://dx.doi.org/10.1111/j.1528-1167.2011.03304.xDOI Listing
December 2011

Transcranial direct current stimulation in refractory continuous spikes and waves during slow sleep: a controlled study.

Epilepsy Res 2011 Nov 31;97(1-2):142-5. Epub 2011 Aug 31.

Department of Neurophysiology, Danish Epilepsy Centre, Dianalund, Denmark.

Cathodal transcranial direct current stimulation (tDCS) decreases cortical excitability. The purpose of the study was to investigate whether cathodal tDCS could interrupt the continuous epileptiform activity. Five patients with focal, refractory continuous spikes and waves during slow sleep were recruited. Cathodal tDCS and sham stimulation were applied to the epileptic focus, before sleep (1 mA; 20 min). Cathodal tDCS did not reduce the spike-index in any of the patients.
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http://dx.doi.org/10.1016/j.eplepsyres.2011.07.016DOI Listing
November 2011

A prospective study of levetiracetam efficacy in epileptic syndromes with continuous spikes-waves during slow sleep.

Seizure 2011 Oct 12;20(8):635-9. Epub 2011 Jul 12.

Danish Epilepsy Centre, Department of Neurophysiology, Kolonivej 1, 4293 Dianalund, Denmark.

Purpose: To evaluate the add-on effect of levetiracetam (LEV) treatment on the EEG and clinical status of children with continuous spikes-waves during slow sleep (CSWS).

Methods: 20 children with CSWS refractory to other conventional antiepileptic drugs (AEDs) received LEV 45-50 mg/kg/day as add-on treatment, and were prospectively followed for a minimum period of 18 months. The patient population comprised seven cryptogenic, seven symptomatic and six idiopathic cases (atypical benign partial epilepsy, aBECTs). The electrographic evaluation included 24 h EEG recordings taken every six months (minimum of three per child). Electrographically children were categorised as responders, partial responders or non-responders by comparing changes in the spike index (SI) during NREM-sleep with baseline SI before initiation of LEV. The clinical efficacy of LEV was assessed by comparing seizure frequency at the end of follow up with the baseline. The follow up duration varied from 18 to 53 months.

Results: Electrographic response was observed in 11 patients. Eight patients demonstrated a lasing response (more than 12 months): five from symptomatic, two--cryptogenic and one--idiopathic group respectively. Three children showed a partial response (6-12 months): one from symptomatic and two from idiopathic group. Eleven out of the 20 children were seizure free at baseline and during the whole follow up. The rest, six-symptomatic and three-cryptogenic patients, had seizures prior to LEV treatment initiation. Six became seizure free after add-on therapy with LEV, and in three children a significant reduction of seizure frequency was observed.

Conclusion: This study suggests that add-on therapy with LEV is more effective in children with CSWS resulting from a known underlying structural brain lesion (the symptomatic group).
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http://dx.doi.org/10.1016/j.seizure.2011.06.007DOI Listing
October 2011
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