Publications by authors named "Helle Hjalgrim"

71 Publications

Risk factors of paradoxical reactions to anti-seizure medication in genetic generalized epilepsy.

Epilepsy Res 2021 Feb 4;170:106547. Epub 2021 Jan 4.

Department of Neurology, Odense University Hospital, Denmark; Department of Clinical Research, University of Southern Denmark, Denmark; OPEN, Open Patient Data Explorative Network, Odense University Hospital, Denmark. Electronic address:

This study aimed at providing valid estimates for the risk of clinically relevant seizure aggravation by recommended anti-seizure medications in patients with Genetic Generalized Epilepsy (GGE). To this aim, treatment response, side effects and paradoxical reactions to anti-seizure treatment were retrospectively assessed in a near-population based cohort comprising 471 adult GGE patients. A total of 1046 treatment attempts were analyzed (lamotrigine: 351, valproic acid: 295, levetiracetam: 249, primidone/phenobarbital: 94, zonisamide: 57). Under lamotrigine, seizure aggravation was observed in 15 patients (two patients during levetiracetam, one patient during zonisamide, none during phenobarbital and valproic acid). All but two patients with paradoxical reactions to lamotrigine were diagnosed with juvenile myoclonic epilepsy (JME), otherwise, the clinical and electroencephalographic characteristics of patients with paradoxical reactions did not differ. At treatment start, the estimated risk of a paradoxical reaction to lamotrigine was 7.9 % in JME patients (n = 190). For all GGE patients (incl. JME), the estimated risk of clinically relevant seizure aggravation under treatment with lamotrigine was 3.7 % (1.8 % for zonisamide and 0.8 % for levetiracetam). In conclusion, clinical significant aggravation of seizure frequency is common in lamotrigine-treated JME patients but rare in patients with other GGE subsyndromes or under treatment with other recommended anti-seizure medication.
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http://dx.doi.org/10.1016/j.eplepsyres.2020.106547DOI Listing
February 2021

A Survey on Cannabinoid Treatment of Pediatric Epilepsy Among Neuropediatricians in Scandinavia and Germany.

Front Pediatr 2020 24;8:416. Epub 2020 Jul 24.

Department of Child Neurology and Rehabilitation (HABU-A), Sørlandet Hospital, Arendal, Norway.

There is an increasing interest in cannabinoid-based products for the treatment of refractory pediatric epilepsy. However, a licensed cannabidiol (CBD) product was first approved for use by the European regulatory authorities in 2019. We aimed to obtain knowledge about clinical experience and attitudes toward cannabinoid use for epilepsy treatment among neuropediatricians in Scandinavia and Germany in the era before a CBD-product was commercially licensed and available. An internet-based questionnaire (Survey Monkey) was distributed by email to members of neuropediatric societies in Sweden, Germany, Denmark, and Norway between February and April 2018. One reminder email was sent. Eighty-six responded. Only 10 of 86 (12%) respondents had personal experience with off-label prescription of cannabinoid-based products, mainly for severe refractory pediatric epilepsies like Dravet syndrome and Lennox-Gastaut syndrome. However, 49 respondents (57%) had been exposed to relatives of patients that had requested or wanted to discuss cannabinoid therapy, and 32 (37%) respondents knew about cannabinoid self-medication. The knowledge regarding cannabinoid-based therapy among the respondents was overall limited. Main reasons for not prescribing cannabinoid-based therapy were concerns about law regulations and lack of an available product. Off-label cannabinoid-based therapy for pediatric epilepsy was not widely prescribed by neuropediatricians in Scandinavia and Germany in 2018.
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http://dx.doi.org/10.3389/fped.2020.00416DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7396558PMC
July 2020

Patterns and prognostic markers for treatment response in generalized epilepsies.

Neurology 2020 11 14;95(18):e2519-e2528. Epub 2020 Aug 14.

From the Department of Neurology (J.G., C.P.B.) and Open Patient Data Explorative Network (C.P.B.), Odense University Hospital; Department of Clinical Research (J.G., C.P.B.), University of Southern Denmark, Odense; Epilepsy Hospital Filadelfia (H.H.), Dianalund; Amplexa Genetics A/S (H.H., G.R.), Odense; and University of Copenhagen (G.R.), Denmark.

Objective: To determine the pattern of treatment response in patients with idiopathic generalized epilepsy (IGE) and whether routinely assessed clinical and neurophysiological parameters allow predicting response to lamotrigine, levetiracetam, or valproic acid.

Methods: In 328 adult patients with IGE, demographic data, imaging, EEG data, current and prior antiepileptic treatment, treatment outcome, and side effects were analyzed from the patients' medical files and patient interviews.

Results: Seizure freedom with acceptable side effects at the first attempt was achieved in 61 (18.6%) patients. One hundred four (31.7%) patients tried ≥3 antiepileptic drugs before achieving seizure control at the last follow-up. Lamotrigine, levetiracetam, and valproic acid showed differential response rates (39.8% vs 47.5% vs 71.1%) that were most pronounced in patients with juvenile myoclonic epilepsy. The risk of having side effects was higher with valproic acid (23.7%) than with lamotrigine (10.4%) or levetiracetam (20.4%) treatment, contributing to the low retention rate of valproic acid (53.7%). Treatment resistance was associated with established risk factors. Multivariate analyses aiming at identifying clinical indicators for response to specific drugs did not reveal putative biomarkers when corrected for drug resistance.

Conclusion: Despite a high rate of seizure control, the chance of achieving seizure control and acceptable side effects at first attempt was low due to an inverse association of effectiveness and side effects of the 3 most commonly used drugs. Routinely assessed clinical parameters were not indicative for response to specific drugs.

Classification Of Evidence: This study provides Class II evidence that for patients with IGE, various clinical factors do not predict a response to specific antiepileptic drugs.
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http://dx.doi.org/10.1212/WNL.0000000000010644DOI Listing
November 2020

The clinical spectrum of familial and sporadic idiopathic generalized epilepsy.

Epilepsy Res 2020 09 1;165:106374. Epub 2020 Jun 1.

Department of Neurology, Odense University Hospital, Sdr. Boulevard 29, 5000 Odense, Denmark; Department of Clinical Research, University of Southern Denmark, Winsløwparken 19, 5000 Odense, Denmark; OPEN, Open Patient Data Explorative Network, Odense University Hospital, Sdr. Boulevard 29, 5000 Odense, Denmark. Electronic address:

Objective: Although the genetic origin of Idiopathic/Genetic Generalized Epilepsy (IGE) is hardly disputed, only a minority of patients show Mendelian inheritance. We here questioned if clinical characteristics like long-term outcome and treatment response differ between patients with sporadic and familial IGE.

Methods: In a near-population based cohort of IGE patients, clinical characteristics, treatment response and family history of 443 IGE patients were analyzed. In patients reporting at least one close relative (max. 3rd grade) with suspected IGE, we designed pedigrees and estimated possible inheritance.

Results: We found 121 patients (27.3%) with a positive family history of IGE, 322 (72.7%) patients had sporadic IGE. Pedigrees suggesting possible autosomal-dominant pattern of inheritance were found in 52 (11.7%) patients. Clinical characteristics, seizure frequency, surrogate markers for social outcome, psychiatric and somatic comorbidity, seizure type, EEG features, treatment response to lamotrigine, levetiracetam or valproic acid and risk of treatment resistance were similar in all groups.

Conclusion: Familial and sporadic IGE patients do not differ in terms of clinical phenotype and treatment response.
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http://dx.doi.org/10.1016/j.eplepsyres.2020.106374DOI Listing
September 2020

Defining and expanding the phenotype of -associated developmental epileptic encephalopathy.

Neurol Genet 2019 Dec 10;5(6):e373. Epub 2019 Dec 10.

Department of Epilepsy Genetics and Precision Medicine (K.J.M., E.G., G.R., R.S.M.), The Danish Epilepsy Centre Filadelfia, Dianalund, Denmark; Institute for Regional Health Services (K.J.M., E.G., R.S.M.), University of Southern Denmark, Odense; Institute of Human Genetics (D.M., R. Jamra, A.F., J.R.L.), University of Leipzig Medical Center, Germany; Institute of Structural Biology (R. Janowski, D.N.), Helmholtz Zentrum München - German Research Center for Environmental Health, Neuherberg, Germany; Department of Paediatric Radiology (C.R.), University of Leipzig Medical Center, Germany; Department of Epilepsy, Sleep and Pediatric Neurophysiology (J.T.), Lyon University Hospital, France; Neuropediatric Unit (A.-L.P., D.M.V., G.L.), Lyon University Hospital, France; Department of Medical Genetics (N.C., G.L.), Lyon University Hospital, France; GenDev Team (N.C.), CNRS UMR 5292, INSERM U1028, CNRL and University of Lyon, France; Department of Genetics (E.B.), University Medical Center Utrecht, The Netherlands; Department of Child Neurology (K.G.), Brain Center Rudolf Magnus, University Medical Center Utrecht, The Netherlands; Department of Paediatrics (A.P.B.), Copenhagen University Hospital Rigshospitalet, Denmark; Baylor College of Medicine (S.M., K.N.), Children's Hospital of San Antonio; Undiagnosed Diseases Program (G.B., C.P.), Genetic Services of Western Australia, Department of Health, Government of Western Australia, Perth; Western Australian Register of Developmental Anomalies (G.B., D.G.), Australia; Telethon Kids Institute and the School of Paediatrics and Child Health (G.B.), University of Western Australia, Perth; Linear Clinical Research (L.D.), WA, Australia; Center of Human Genetics (S.S), Jena University Hospital, Germany; Department of Neuropediatrics (A.D.), Jena University Hospital, Germany; Division of Neurology (K.L.H.), Children's Hospital of Philadelphia, PA; Division of Neuropediatrics (A.M.), University of Leipzig Medical Center, Germany; Amplexa Genetics (H.H.), Odense, Denmark; Clinic for Children (H.H.), Værløse, Denmark; Center for Integrative Brain Research (G.M.), Seattle Children's Research Institute, WA; Department of Pediatrics (G.M.), University of Washington, Seattle; Medical Genetics Unit (F.B.), Department of Life, Health and Environmental Sciences, University of L'Aquila, Italy; Istituto Dermopatico dell'Immacolata (F.B.), IDI-IRCCS, Rome, Italy; Institute of Human Genetics (T.B., M.H.), University Medical Center Hamburg-Eppendorf, Germany; Childrens Hospital (J.D.), University Medical Center Hamburg-Eppendorf, Germany; University of Copenhagen (G.R.), Denmark; Institute for Human Genetics (P.M.), University Hospital Magdeburg, Germany; Children's Hospital A. Meyer (R.G., A.V.), University of Florence, Italy; and Institute of Pharmaceutical Biotechnology (D.N.), Ulm University, Germany.

Objective: The study is aimed at widening the clinical and genetic spectrum and at assessing genotype-phenotype associations in encephalopathy.

Methods: Through diagnostic gene panel screening in an epilepsy cohort, and recruiting through GeneMatcher and our international network, we collected 10 patients with biallelic variants. In addition, we collected data on 12 patients described in the literature to further delineate the associated phenotype in a total cohort of 22 patients. Computer modeling was used to assess changes on protein folding.

Results: Biallelic pathogenic variants in cause a triad of progressive microcephaly, moderate to severe developmental delay, and early-onset epilepsy. Microcephaly was present at birth in 65%, and in all patients at follow-up. Moderate (14%) or severe (73%) developmental delay was characteristic, with no achievement of sitting (85%), walking (86%), or talking (90%). Additional features included irritability (91%), hypertonia/spasticity (75%), hypotonia (83%), stereotypic movements (75%), and short stature (56%). Seventy-nine percent had pharmacoresistant epilepsy with mainly neonatal onset. Characteristic cranial MRI findings include early-onset progressive atrophy of cerebral cortex (89%) and cerebellum (61%), enlargement of ventricles (95%), and age-dependent delayed myelination (88%). A small subset of patients displayed a less severe phenotype.

Conclusions: These data revealed first genotype-phenotype associations and may serve for improved interpretation of new variants and well-founded genetic counseling.
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http://dx.doi.org/10.1212/NXG.0000000000000373DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6927360PMC
December 2019

Estimating the effect size of the 15Q11.2 BP1-BP2 deletion and its contribution to neurodevelopmental symptoms: recommendations for practice.

J Med Genet 2019 10 26;56(10):701-710. Epub 2019 Aug 26.

Department of Pediatrics, University of Montreal, Montreal, Québec, Canada

Background: The 15q11.2 deletion is frequently identified in the neurodevelopmental clinic. Case-control studies have associated the 15q11.2 deletion with neurodevelopmental disorders, and clinical case series have attempted to delineate a microdeletion syndrome with considerable phenotypic variability. The literature on this deletion is extensive and confusing, which is a challenge for genetic counselling. The aim of this study was to estimate the effect size of the 15q11.2 deletion and quantify its contribution to neurodevelopmental disorders.

Methods: We performed meta-analyses on new and previously published case-control studies and used statistical models trained in unselected populations with cognitive assessments. We used new (n=241) and previously published (n=150) data from a clinically referred group of deletion carriers. 15q11.2 duplications (new n=179 and previously published n=35) were used as a neutral control variant.

Results: The deletion decreases IQ by 4.3 points. The estimated ORs and respective frequencies in deletion carriers for intellectual disabilities, schizophrenia and epilepsy are 1.7 (3.4%), 1.5 (2%) and 3.1 (2.1%), respectively. There is no increased risk for heart malformations and autism. In the clinically referred group, the frequency and nature of symptoms in deletions are not different from those observed in carriers of the 15q11.2 duplication suggesting that most of the reported symptoms are due to ascertainment bias.

Conclusions: We recommend that the deletion should be classified as 'pathogenic of mild effect size'. Since it explains only a small proportion of the phenotypic variance in carriers, it is not worth discussing in the developmental clinic or in a prenatal setting.
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http://dx.doi.org/10.1136/jmedgenet-2018-105879DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6817694PMC
October 2019

Update on the genetics of the epilepsy-aphasia spectrum and role of GRIN2A mutations.

Epileptic Disord 2019 Jun;21(S1):41-47

Aix-Marseille University, INSERM UMR1249, INMED, Marseille, France.

Formerly idiopathic, focal epilepsies (IFE) are self-limiting, "age-related" diseases that mainly occur during critical developmental periods. Childhood epilepsy with centrotemporal spikes, or Rolandic epilepsy (RE), is the most frequent form of IFE. Together with the Landau-Kleffner syndrome and the epileptic Encephalopathy related to Status Epilepticus during slow Sleep syndrome (ESES), RE is part of a single and continuous spectrum of childhood epilepsies and epileptic encephalopathies with acquired cognitive, behavioral and speech and/or language impairment, known as the epilepsy-aphasia spectrum (EAS). The pathophysiology has long been attributed to an elusive and complex interplay between brain development and maturation processes on the one hand, and susceptibility genes on the other hand. Studies based on the variable combination of molecular cytogenetics, Sanger and next-generation sequencing tools, and functional assays have led to the identification and validation of genetic mutations in the GRIN2A gene that can directly cause various types of EAS disorders. The recent identification of GRIN2A defects in EAS represents a first and major break-through in our understanding of the underlying pathophysiological mechanisms. In this review, we describe the current knowledge on the genetic architecture of IFE.
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http://dx.doi.org/10.1684/epd.2019.1056DOI Listing
June 2019

PIGT-CDG, a disorder of the glycosylphosphatidylinositol anchor: description of 13 novel patients and expansion of the clinical characteristics.

Genet Med 2019 10 12;21(10):2216-2223. Epub 2019 Apr 12.

Danish Epilepsy Centre, Dianalund, Denmark.

Purpose: To provide a detailed electroclinical description and expand the phenotype of PIGT-CDG, to perform genotype-phenotype correlation, and to investigate the onset and severity of the epilepsy associated with the different genetic subtypes of this rare disorder. Furthermore, to use computer-assisted facial gestalt analysis in PIGT-CDG and to the compare findings with other glycosylphosphatidylinositol (GPI) anchor deficiencies.

Methods: We evaluated 13 children from eight unrelated families with homozygous or compound heterozygous pathogenic variants in PIGT.

Results: All patients had hypotonia, severe developmental delay, and epilepsy. Epilepsy onset ranged from first day of life to two years of age. Severity of the seizure disorder varied from treatable seizures to severe neonatal onset epileptic encephalopathies. The facial gestalt of patients resembled that of previously published PIGT patients as they were closest to the center of the PIGT cluster in the clinical face phenotype space and were distinguishable from other gene-specific phenotypes.

Conclusion: We expand our knowledge of PIGT. Our cases reaffirm that the use of genetic testing is essential for diagnosis in this group of disorders. Finally, we show that computer-assisted facial gestalt analysis accurately assigned PIGT cases to the multiple congenital anomalies-hypotonia-seizures syndrome phenotypic series advocating the additional use of next-generation phenotyping technology.
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http://dx.doi.org/10.1038/s41436-019-0512-3DOI Listing
October 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

Analysis of shared heritability in common disorders of the brain.

Science 2018 06;360(6395)

Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA.

Disorders of the brain can exhibit considerable epidemiological comorbidity and often share symptoms, provoking debate about their etiologic overlap. We quantified the genetic sharing of 25 brain disorders from genome-wide association studies of 265,218 patients and 784,643 control participants and assessed their relationship to 17 phenotypes from 1,191,588 individuals. Psychiatric disorders share common variant risk, whereas neurological disorders appear more distinct from one another and from the psychiatric disorders. We also identified significant sharing between disorders and a number of brain phenotypes, including cognitive measures. Further, we conducted simulations to explore how statistical power, diagnostic misclassification, and phenotypic heterogeneity affect genetic correlations. These results highlight the importance of common genetic variation as a risk factor for brain disorders and the value of heritability-based methods in understanding their etiology.
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http://dx.doi.org/10.1126/science.aap8757DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6097237PMC
June 2018

Introduction: The European Association of Epilepsy Centers (EAEC).

Epilepsy Behav 2017 11 5;76S:S3. Epub 2017 Sep 5.

Danish Epilepsy Center, Filadelfia, Dianalund, Denmark.

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http://dx.doi.org/10.1016/j.yebeh.2017.07.019DOI Listing
November 2017

The European Association of Epilepsy Centers (EAEC): Just Old Europe or a modern model?

Epilepsy Behav 2017 11 4;76S:S1-S2. Epub 2017 Sep 4.

Dianalund Epilepsy Center, Dianalund, Denmark.

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http://dx.doi.org/10.1016/j.yebeh.2017.07.018DOI Listing
November 2017

[Dietary treatment of medically refractory epilepsy in children and adolescents].

Ugeskr Laeger 2017 Apr;179(14)

Ketogenic diet (KD) is used worldwide in the treatment of medically refractory epilepsy. Since the introduction of KD in the early 1900s, new approaches such as medium-chain triglyceride ketogenic diet, modified Atkins diet and low glycaemic index treatment have been suggested as alternative treatments. Several studies have documented significant seizure reduction from all four diets. The aim of this article is to give an overview of the effect of dietary treatment and to discuss advantages in initiating dietary treatment as an early treatment instead of as a last option.
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April 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

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

Phenotypic spectrum of GABRA1: From generalized epilepsies to severe epileptic encephalopathies.

Neurology 2016 09 12;87(11):1140-51. Epub 2016 Aug 12.

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

Objective: To delineate phenotypic heterogeneity, we describe the clinical features of a cohort of patients with GABRA1 gene mutations.

Methods: Patients with GABRA1 mutations were ascertained through an international collaboration. Clinical, EEG, and genetic data were collected. Functional analysis of 4 selected mutations was performed using the Xenopus laevis oocyte expression system.

Results: The study included 16 novel probands and 3 additional family members with a disease-causing mutation in the GABRA1 gene. The phenotypic spectrum varied from unspecified epilepsy (1), juvenile myoclonic epilepsy (2), photosensitive idiopathic generalized epilepsy (1), and generalized epilepsy with febrile seizures plus (1) to severe epileptic encephalopathies (11). In the epileptic encephalopathy group, the patients had seizures beginning between the first day of life and 15 months, with a mean of 7 months. Predominant seizure types in all patients were tonic-clonic in 9 participants (56%) and myoclonic seizures in 5 (31%). EEG showed a generalized photoparoxysmal response in 6 patients (37%). Four selected mutations studied functionally revealed a loss of function, without a clear genotype-phenotype correlation.

Conclusions: GABRA1 mutations make a significant contribution to the genetic etiology of both benign and severe epilepsy syndromes. Myoclonic and tonic-clonic seizures with pathologic response to photic stimulation are common and shared features in both mild and severe phenotypes.
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http://dx.doi.org/10.1212/WNL.0000000000003087DOI Listing
September 2016

Pitfalls in genetic testing: the story of missed SCN1A mutations.

Mol Genet Genomic Med 2016 Jul 14;4(4):457-64. Epub 2016 Apr 14.

Department of Neuropediatrics University Medical Center Schleswig-Holstein Kiel Germany.

Background: Sanger sequencing, still the standard technique for genetic testing in most diagnostic laboratories and until recently widely used in research, is gradually being complemented by next-generation sequencing (NGS). No single mutation detection technique is however perfect in identifying all mutations. Therefore, we wondered to what extent inconsistencies between Sanger sequencing and NGS affect the molecular diagnosis of patients. Since mutations in SCN1A, the major gene implicated in epilepsy, are found in the majority of Dravet syndrome (DS) patients, we focused on missed SCN1A mutations.

Methods: We sent out a survey to 16 genetic centers performing SCN1A testing.

Results: We collected data on 28 mutations initially missed using Sanger sequencing. All patients were falsely reported as SCN1A mutation-negative, both due to technical limitations and human errors.

Conclusion: We illustrate the pitfalls of Sanger sequencing and most importantly provide evidence that SCN1A mutations are an even more frequent cause of DS than already anticipated.
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http://dx.doi.org/10.1002/mgg3.217DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4947864PMC
July 2016

Delineating the GRIN1 phenotypic spectrum: A distinct genetic NMDA receptor encephalopathy.

Neurology 2016 06 6;86(23):2171-8. Epub 2016 May 6.

Objective: To determine the phenotypic spectrum caused by mutations in GRIN1 encoding the NMDA receptor subunit GluN1 and to investigate their underlying functional pathophysiology.

Methods: We collected molecular and clinical data from several diagnostic and research cohorts. Functional consequences of GRIN1 mutations were investigated in Xenopus laevis oocytes.

Results: We identified heterozygous de novo GRIN1 mutations in 14 individuals and reviewed the phenotypes of all 9 previously reported patients. These 23 individuals presented with a distinct phenotype of profound developmental delay, severe intellectual disability with absent speech, muscular hypotonia, hyperkinetic movement disorder, oculogyric crises, cortical blindness, generalized cerebral atrophy, and epilepsy. Mutations cluster within transmembrane segments and result in loss of channel function of varying severity with a dominant-negative effect. In addition, we describe 2 homozygous GRIN1 mutations (1 missense, 1 truncation), each segregating with severe neurodevelopmental phenotypes in consanguineous families.

Conclusions: De novo GRIN1 mutations are associated with severe intellectual disability with cortical visual impairment as well as oculomotor and movement disorders being discriminating phenotypic features. Loss of NMDA receptor function appears to be the underlying disease mechanism. The identification of both heterozygous and homozygous mutations blurs the borders of dominant and recessive inheritance of GRIN1-associated disorders.
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http://dx.doi.org/10.1212/WNL.0000000000002740DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4898312PMC
June 2016

Reply.

Ann Neurol 2016 07 10;80(1):168-9. Epub 2016 May 10.

Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany.

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http://dx.doi.org/10.1002/ana.24669DOI Listing
July 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

From unwitnessed fatality to witnessed rescue: Nonpharmacologic interventions in sudden unexpected death in epilepsy.

Epilepsia 2016 Jan;57 Suppl 1:26-34

Department of Neurology, Columbia University, New York, New York, U.S.A.

Sudden unexpected death in epilepsy (SUDEP) risk reduction remains a critical aim in epilepsy care. To date, only aggressive medical and surgical efforts to control seizures have been demonstrated to be of benefit. Incomplete understanding of SUDEP mechanisms limits the development of more specific interventions. Periictal cardiorespiratory dysfunction is implicated in SUDEP; postictal electroencephalography (EEG) suppression, coma, and immobility may also play a role. Nocturnal supervision is protective against SUDEP, presumably by permitting intervention in the case of a life-threatening event. Resuscitative efforts were implemented promptly in near-SUDEP cases but delayed in SUDEP deaths in the Mortality in Epilepsy Monitoring Unit Study (MORTEMUS) study. Nursing interventions--including repositioning, oral suctioning, and oxygen administration--reduce seizure duration, respiratory dysfunction, and EEG suppression in the epilepsy monitoring unit (EMU), but have not been studied in outpatients. Cardiac pacemakers or cardioverter-defibrillator devices may be of benefit in a few select individuals. A role for implantable neurostimulators has not yet been established. Seizure detection devices, including those that monitor generalized tonic-clonic seizure-associated movements or cardiorespiratory parameters, may provide a means to permit timely periictal intervention. However, these and other devices, such as antisuffocation pillows, have not been adequately investigated with respect to SUDEP prevention.
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http://dx.doi.org/10.1111/epi.13231DOI Listing
January 2016

Benign infantile seizures and paroxysmal dyskinesia caused by an SCN8A mutation.

Ann Neurol 2016 Mar 13;79(3):428-36. Epub 2016 Feb 13.

Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany.

Objective: Benign familial infantile seizures (BFIS), paroxysmal kinesigenic dyskinesia (PKD), and their combination-known as infantile convulsions and paroxysmal choreoathetosis (ICCA)-are related autosomal dominant diseases. PRRT2 (proline-rich transmembrane protein 2 gene) has been identified as the major gene in all 3 conditions, found to be mutated in 80 to 90% of familial and 30 to 35% of sporadic cases.

Methods: We searched for the genetic defect in PRRT2-negative, unrelated families with BFIS or ICCA using whole exome or targeted gene panel sequencing, and performed a detailed cliniconeurophysiological workup.

Results: In 3 families with a total of 16 affected members, we identified the same, cosegregating heterozygous missense mutation (c.4447G>A; p.E1483K) in SCN8A, encoding a voltage-gated sodium channel. A founder effect was excluded by linkage analysis. All individuals except 1 had normal cognitive and motor milestones, neuroimaging, and interictal neurological status. Fifteen affected members presented with afebrile focal or generalized tonic-clonic seizures during the first to second year of life; 5 of them experienced single unprovoked seizures later on. One patient had seizures only at school age. All patients stayed otherwise seizure-free, most without medication. Interictal electroencephalogram (EEG) was normal in all cases but 2. Five of 16 patients developed additional brief paroxysmal episodes in puberty, either dystonic/dyskinetic or "shivering" attacks, triggered by stretching, motor initiation, or emotional stimuli. In 1 case, we recorded typical PKD spells by video-EEG-polygraphy, documenting a cortical involvement.

Interpretation: Our study establishes SCN8A as a novel gene in which a recurrent mutation causes BFIS/ICCA, expanding the clinical-genetic spectrum of combined epileptic and dyskinetic syndromes.
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http://dx.doi.org/10.1002/ana.24580DOI Listing
March 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

Burden analysis of rare microdeletions suggests a strong impact of neurodevelopmental genes in genetic generalised epilepsies.

PLoS Genet 2015 May 7;11(5):e1005226. Epub 2015 May 7.

EPICURE Consortium; Neurogenetics Group, VIB Department of Molecular Genetics, University of Antwerp, Antwerp, Belgium; Laboratory of Neurogenetics, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium.

Genetic generalised epilepsy (GGE) is the most common form of genetic epilepsy, accounting for 20% of all epilepsies. Genomic copy number variations (CNVs) constitute important genetic risk factors of common GGE syndromes. In our present genome-wide burden analysis, large (≥ 400 kb) and rare (< 1%) autosomal microdeletions with high calling confidence (≥ 200 markers) were assessed by the Affymetrix SNP 6.0 array in European case-control cohorts of 1,366 GGE patients and 5,234 ancestry-matched controls. We aimed to: 1) assess the microdeletion burden in common GGE syndromes, 2) estimate the relative contribution of recurrent microdeletions at genomic rearrangement hotspots and non-recurrent microdeletions, and 3) identify potential candidate genes for GGE. We found a significant excess of microdeletions in 7.3% of GGE patients compared to 4.0% in controls (P = 1.8 x 10-7; OR = 1.9). Recurrent microdeletions at seven known genomic hotspots accounted for 36.9% of all microdeletions identified in the GGE cohort and showed a 7.5-fold increased burden (P = 2.6 x 10-17) relative to controls. Microdeletions affecting either a gene previously implicated in neurodevelopmental disorders (P = 8.0 x 10-18, OR = 4.6) or an evolutionarily conserved brain-expressed gene related to autism spectrum disorder (P = 1.3 x 10-12, OR = 4.1) were significantly enriched in the GGE patients. Microdeletions found only in GGE patients harboured a high proportion of genes previously associated with epilepsy and neuropsychiatric disorders (NRXN1, RBFOX1, PCDH7, KCNA2, EPM2A, RORB, PLCB1). Our results demonstrate that the significantly increased burden of large and rare microdeletions in GGE patients is largely confined to recurrent hotspot microdeletions and microdeletions affecting neurodevelopmental genes, suggesting a strong impact of fundamental neurodevelopmental processes in the pathogenesis of common GGE syndromes.
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http://dx.doi.org/10.1371/journal.pgen.1005226DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4423931PMC
May 2015

Dysregulation of FOXG1 by ring chromosome 14.

Mol Cytogenet 2015 9;8:24. Epub 2015 Apr 9.

Department of Cellular and Molecular Medicine, Wilhelm Johannsen Centre for Functional Genome Research, University of Copenhagen, Copenhagen, Denmark.

In this study we performed molecular characterization of a patient with an extra ring chromosome derived from chromosome 14, with severe intellectual disability, epilepsy, cerebral paresis, tetraplegia, osteoporosis and severe thoraco-lumbal scoliosis. Array CGH analysis did not show any genomic imbalance but conventional karyotyping and FISH analysis revealed the presence of an interstitial 14q12q24.3 deletion and an extra ring chromosome derived from the deleted material. The deletion and ring chromosome breakpoints were identified at base-pair level by mate-pair and Sanger sequencing. Both breakpoints disrupted putative long non-coding RNA genes (TCONS00022561;RP11-148E17.1) of unknown function. However, the proximal breakpoint was 225 kb downstream of the forkhead box G1 gene (FOXG1), within the known regulatory landscape of FOXG1. The patient represents the first case of a r(14) arising from an interstitial excision where the phenotype is compatible with dysregulation of FOXG1. In turn, the phenotypic overlap between the present case, the FOXG1 syndrome and the r(14) syndrome supports that dysregulation of FOXG1 may contribute to the classical r(14)-syndrome, likely mediated by dynamic mosaicism.
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http://dx.doi.org/10.1186/s13039-015-0129-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4404611PMC
April 2015

The incidence of SCN1A-related Dravet syndrome in Denmark is 1:22,000: a population-based study from 2004 to 2009.

Epilepsia 2015 Apr 16;56(4):e36-9. Epub 2015 Mar 16.

Department of Clinical Genetics, Copenhagen University Hospital, Copenhagen, Denmark.

Dravet syndrome is a severe infantile-onset epileptic encephalopathy associated with mutations in the sodium channel alpha-1 subunit gene SCN1A. We aimed to describe the incidence of Dravet syndrome in the Danish population. Based on a 6-year birth cohort from 2004 to 2009, we propose an incidence of 1:22,000, which is higher than what has been established earlier. We identified 17 cases with SCN1A mutation-positive Dravet syndrome. Fifteen patients were found, by conventional Sanger sequencing. Two additional patients with clinical Dravet syndrome, but without a detectable SCN1A mutation by Sanger sequencing, were diagnosed with a SCN1A mutation after using a targeted next-generation sequencing gene panel.
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http://dx.doi.org/10.1111/epi.12927DOI Listing
April 2015

The phenotypic spectrum of SCN8A encephalopathy.

Neurology 2015 Feb 7;84(5):480-9. Epub 2015 Jan 7.

Objective: SCN8A encodes the sodium channel voltage-gated α8-subunit (Nav1.6). SCN8A mutations have recently been associated with epilepsy and neurodevelopmental disorders. We aimed to delineate the phenotype associated with SCN8A mutations.

Methods: We used high-throughput sequence analysis of the SCN8A gene in 683 patients with a range of epileptic encephalopathies. In addition, we ascertained cases with SCN8A mutations from other centers. A detailed clinical history was obtained together with a review of EEG and imaging data.

Results: Seventeen patients with de novo heterozygous mutations of SCN8A were studied. Seizure onset occurred at a mean age of 5 months (range: 1 day to 18 months); in general, seizures were not triggered by fever. Fifteen of 17 patients had multiple seizure types including focal, tonic, clonic, myoclonic and absence seizures, and epileptic spasms; seizures were refractory to antiepileptic therapy. Development was normal in 12 patients and slowed after seizure onset, often with regression; 5 patients had delayed development from birth. All patients developed intellectual disability, ranging from mild to severe. Motor manifestations were prominent including hypotonia, dystonia, hyperreflexia, and ataxia. EEG findings comprised moderate to severe background slowing with focal or multifocal epileptiform discharges.

Conclusion: SCN8A encephalopathy presents in infancy with multiple seizure types including focal seizures and spasms in some cases. Outcome is often poor and includes hypotonia and movement disorders. The majority of mutations arise de novo, although we observed a single case of somatic mosaicism in an unaffected parent.
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http://dx.doi.org/10.1212/WNL.0000000000001211DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4336074PMC
February 2015

Automated differentiation between epileptic and nonepileptic convulsive seizures.

Ann Neurol 2015 Feb 17;77(2):348-51. Epub 2015 Jan 17.

Department of Clinical Neurophysiology, Danish Epilepsy Center, Dianalund, Denmark; Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark.

Our objective was the clinical validation of an automated algorithm based on surface electromyography (EMG) for differentiation between convulsive epileptic and psychogenic nonepileptic seizures (PNESs). Forty-four consecutive episodes with convulsive events were automatically analyzed with the algorithm: 25 generalized tonic-clonic seizures (GTCSs) from 11 patients, and 19 episodes of convulsive PNES from 13 patients. The gold standard was the interpretation of the video-electroencephalographic recordings by experts blinded to the EMG results. The algorithm correctly classified 24 GTCSs (96%) and 18 PNESs (95%). The overall diagnostic accuracy was 95%. This algorithm is useful for distinguishing between epileptic and psychogenic convulsive seizures.
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http://dx.doi.org/10.1002/ana.24338DOI Listing
February 2015

Mutations in STX1B, encoding a presynaptic protein, cause fever-associated epilepsy syndromes.

Nat Genet 2014 Dec 2;46(12):1327-32. Epub 2014 Nov 2.

Section of Complex Genetics, Department of Medical Genetics, University Medical Center Utrecht, Utrecht, the Netherlands.

Febrile seizures affect 2-4% of all children and have a strong genetic component. Recurrent mutations in three main genes (SCN1A, SCN1B and GABRG2) have been identified that cause febrile seizures with or without epilepsy. Here we report the identification of mutations in STX1B, encoding syntaxin-1B, that are associated with both febrile seizures and epilepsy. Whole-exome sequencing in independent large pedigrees identified cosegregating STX1B mutations predicted to cause an early truncation or an in-frame insertion or deletion. Three additional nonsense or missense mutations and a de novo microdeletion encompassing STX1B were then identified in 449 familial or sporadic cases. Video and local field potential analyses of zebrafish larvae with antisense knockdown of stx1b showed seizure-like behavior and epileptiform discharges that were highly sensitive to increased temperature. Wild-type human syntaxin-1B but not a mutated protein rescued the effects of stx1b knockdown in zebrafish. Our results thus implicate STX1B and the presynaptic release machinery in fever-associated epilepsy syndromes.
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http://dx.doi.org/10.1038/ng.3130DOI Listing
December 2014

Reduced ceramide synthase 2 activity causes progressive myoclonic epilepsy.

Ann Clin Transl Neurol 2014 Feb 13;1(2):88-98. Epub 2014 Jan 13.

Department of Biochemistry and Molecular Biology, University of Southern Denmark Odense M, DK-5230, Denmark.

Objective: Ceramides are precursors of complex sphingolipids (SLs), which are important for normal functioning of both the developing and mature brain. Altered SL levels have been associated with many neurodegenerative disorders, including epilepsy, although few direct links have been identified between genes involved in SL metabolism and epilepsy.

Methods: We used quantitative real-time PCR, Western blotting, and enzymatic assays to determine the mRNA, protein, and activity levels of ceramide synthase 2 (CERS2) in fiibroblasts isolated from parental control subjects and from a patient diagnosed with progressive myoclonic epilepsy (PME). Mass spectrometry and fluorescence microscopy were used to examine the effects of reduced CERS2 activity on cellular lipid composition and plasma membrane functions.

Results: We identify a novel 27 kb heterozygous deletion including the CERS2 gene in a proband diagnosed with PME. Compared to parental controls, levels of CERS2 mRNA, protein, and activity were reduced by ˜50% in fibroblasts isolated from this proband, resulting in significantly reduced levels of ceramides and sphingomyelins containing the very long-chain fatty acids C24:0 and C26:0. The change in SL composition was also reflected in a reduction in cholera toxin B immunofluorescence, indicating that membrane composition and function are altered.

Interpretation: We propose that reduced levels of CERS2, and consequently diminished levels of ceramides and SLs containing very long-chain fatty acids, lead to development of PME.
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http://dx.doi.org/10.1002/acn3.28DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4212479PMC
February 2014
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