Publications by authors named "Dorothée Ville"

52 Publications

KCNT1-related epilepsies and epileptic encephalopathies: phenotypic and mutational spectrum.

Brain 2021 Jun 11. Epub 2021 Jun 11.

Pediatric Neurology Department, Lyon University Hospital, 69500 Bron, France.

Variants in KCNT1, encoding a sodium-gated potassium channel (subfamily T member 1), have been associated with a spectrum of epilepsies and neurodevelopmental disorders. These range from familial autosomal dominant or sporadic sleep-related hypermotor epilepsy ((AD)SHE) to epilepsy of infancy with migrating focal seizures (EIMFS) and include developmental and epileptic encephalopathies (DEE). This study aims to provide a comprehensive overview of the phenotypic and genotypic spectrum of KCNT1 mutation-related epileptic disorders in 248 individuals, including 66 unpreviously published and 182 published cases, the largest cohort reported so far. Four phenotypic groups emerged from our analysis: i) EIMFS (152 individuals, 33 previously unpublished); ii) DEE other than EIMFS (non-EIMFS DEE) (37 individuals, 17 unpublished); iii) (AD)SHE (53 patients, 14 unpublished); iv) other phenotypes (6 individuals, 2 unpublished). In our cohort of 66 new cases, the most common phenotypic features were: a) in EIMFS, heterogeneity of seizure types, including epileptic spasms, epilepsy improvement over time, no epilepsy-related deaths; b) in non-EIMFS DEE, possible onset with West syndrome, occurrence of atypical absences, possible evolution to DEE with SHE features; one case of sudden unexplained death in epilepsy (SUDEP); c) in (AD)SHE, we observed a high prevalence of drug-resistance, although seizure frequency improved with age in some individuals, appearance of cognitive regression after seizure onset in all patients, no reported severe psychiatric disorders, although behavioural/psychiatric comorbidities were reported in about 50% of the patients, SUDEP in one individual; d) other phenotypes in individuals with mutation of KCNT1 included temporal lobe epilepsy, and epilepsy with tonic-clonic seizures and cognitive regression. Genotypic analysis of the whole cohort of 248 individuals showed only missense mutations and one inframe deletion in KCNT1. Although the KCNT1 mutations in affected individuals were seen to be distributed among the different domains of the KCNT1 protein, genotype-phenotype considerations showed many of the (AD)SHE-associated mutations to be clustered around the RCK2 domain in the C-terminus, distal to the NADP domain. Mutations associated with EIMFS/non-EIMFS DEE did not show a particular pattern of distribution in the KCNT1 protein. Recurrent KCNT1 mutations were seen to be associated with both severe and less severe phenotypes. Our study further defines and broadens the phenotypic and genotypic spectrums of KCNT1-related epileptic conditions and emphasizes the increasingly important role of this gene in the pathogenesis of early onset DEEs as well as in focal epilepsies, namely (AD)SHE.
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http://dx.doi.org/10.1093/brain/awab219DOI Listing
June 2021

The phenotypic spectrum of X-linked, infantile onset ALG13-related developmental and epileptic encephalopathy.

Epilepsia 2021 02 7;62(2):325-334. Epub 2021 Jan 7.

Institute of Human Genetics, University of Leipzig Medical Center, Leipzig, Germany.

Objective: Asparagine-linked glycosylation 13 (ALG13) deficiencies have been repeatedly described in the literature with the clinical phenotype of a developmental and epileptic encephalopathy (DEE). Most cases were females carrying the recurrent ALG13 de novo variant, p.(Asn107Ser), with normal transferrin electrophoresis.

Methods: We delineate the phenotypic spectrum of 38 individuals, 37 girls and one boy, 16 of them novel and 22 published, with the most common pathogenic ALG13 variant p.(Asn107Ser) and additionally report the phenotype of three individuals carrying other likely pathogenic ALG13 variants.

Results: The phenotypic spectrum often comprised pharmacoresistant epilepsy with epileptic spasms, mostly with onset within the first 6 months of life and with spasm persistence in one-half of the cases. Tonic seizures were the most prevalent additional seizure type. Electroencephalography showed hypsarrhythmia and at a later stage of the disease in one-third of all cases paroxysms of fast activity with electrodecrement. ALG13-related DEE was usually associated with severe to profound developmental delay; ambulation was acquired by one-third of the cases, whereas purposeful hand use was sparse or completely absent. Hand stereotypies and dyskinetic movements including dystonia or choreoathetosis were relatively frequent. Verbal communication skills were absent or poor, and eye contact and pursuit were often impaired.

Significance: X-linked ALG13-related DEE usually manifests as West syndrome with severe to profound developmental delay. It is predominantly caused by the recurrent de novo missense variant p.(Asn107Ser). Comprehensive functional studies will be able to prove or disprove an association with congenital disorder of glycosylation.
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http://dx.doi.org/10.1111/epi.16761DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7898319PMC
February 2021

Slow Titration of Cannabidiol Add-On in Drug-Resistant Epilepsies Can Improve Safety With Maintained Efficacy in an Open-Label Study.

Front Neurol 2020 12;11:829. Epub 2020 Aug 12.

Department of Pediatric Neurology, Reference Centre for Rare Epilepsies, Hôpital Necker-Enfants Malades, APHP, Paris, France.

To assess adverse events (AEs) and efficacy of add-on cannabidiol (CBD) with a slower titration protocol in pediatric clinical practice. We conducted a prospective, open-label, multicenter study in seven French reference centers for rare epilepsies. Patients had slow titration to reach a target dose of 10 mg/kg/day within at least 1 month and then gradually increased to a maximum dose of 20 mg/kg/day. We analyzed AEs and efficacy at M1 (month 1), M2, and M6, comparing two sets of subgroups: Dravet syndrome (DS) vs. Lennox-Gastaut (LGS) and patients with clobazam (CLB+) vs. patients without (CLB-). One hundred and twenty-five patients were enrolled (62 LGS, 48 DS, 5 Tuberous sclerosis, and 10 other etiologies). Median concomitant antiepileptic drugs (AEDs) was three (25th percentile: 3, 75th percentile: 4). Patients received a dose of 10 (10-12), 14 (10-20), and 15.5 mg/kg/day (10-20) at M1, M2, and M6, respectively. Twenty-six patients discontinued CBD, 19 due to lack of efficacy, 2 due to AEs, 4 for both, and 1 had a sudden unexpected death in epilepsy. AEs were reported in 61 patients (48.8%), mainly somnolence ( = 26), asthenia ( = 20), and behavior disorders ( = 16). Abnormal transaminases (≥3 times) were reported in 11 patients receiving both valproate and clobazam. AEs were significantly higher at M2 ( = 0.03) and increased with the number of AEDs ( = 0.03). At M6, total seizure frequency change from baseline was -41% ± 37.5% (mean ± standard deviation), and 28 patients (37.8%) had a reduction ≥50%. AE and efficacy did not differ between DS vs. LGS and CLB+ vs. CLB- patients. A slower titration of CBD dose delivered better tolerance with comparable efficacy to previous trials. Concomitant CLB did not increase efficacy rates but in a few cases increased AEs. This slow titration scheme should help guide clinicians prescribing CBD and allow patients to benefit from its potential efficacy.
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http://dx.doi.org/10.3389/fneur.2020.00829DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7434926PMC
August 2020

Early-onset epileptic encephalopathy with migrating focal seizures associated with a FARS2 homozygous nonsense variant.

Epileptic Disord 2020 Jun;22(3):327-335

Paediatric Clinical Epileptology and Functional Neurology Department, Reference Center of rare epilepsies, Member of the ERN EpiCARE, University Hospitals of Lyon (HCL), Lyon, France.

Epilepsy of infancy with migrating focal seizures (EIMFS) is now a well-recognized early-onset syndrome included in the ILAE classification of the epilepsies. KCNT1 gain-of-function variants are identified in about half of patients. In the remaining cases, the underlying genetic component is far more heterogeneous with sporadic mutations occasionally reported in SCN1A, SCN2A, SLC12A5, TBC1D24, PLCB1, SLC25A22, and KCNQ2. Here, we report, for the first time, a homozygous deleterious variant in the FARS2 gene, identified using a 115-gene panel for monogenic epilepsies, in a patient with EIMFS. This boy was the second child born to healthy consanguineous parents. The first seizures occurred at six weeks of age. The patient rapidly developed severe epilepsy with focal discharges on EEG, migrating from one brain region to another, highly suggestive of EIMFS. At five months of age, he had daily multifocal clonic seizures and erratic myoclonic fits, which were not consistently related to spikes or spike-and-wave discharges. Neurological status was severely abnormal from onset and the patient died at 10 months of age from respiratory distress. Using the gene panel, a homozygous missense variant of FARS2 was identified, at Chr6 (GRCh37):g.5404829C>T, c.667C>T (NM_001318872.1), inherited from both parents, leading to an arginine-to-cysteine substitution, p.(Arg223Cys). FARS2 is a member of the mitochondrial aminoacyl tRNA transferase (ARS) enzymes. ARS variants are increasingly recognized causes of early-onset epileptic and neurodevelopmental encephalopathies, however, the associated epileptic phenotype is not completely described. This case shows that FARS2-related seizures can mimic EIMFS in the early stage of the disease. Furthermore, in the setting of migrating focal seizures of infancy, FARS2 should be considered as a further candidate gene, and increased lactate level and occurrence of refractory myoclonic seizures are possible key features to suspect FARS deficiency.
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http://dx.doi.org/10.1684/epd.2020.1168DOI Listing
June 2020

Phenotypic and Imaging Spectrum Associated With WDR45.

Pediatr Neurol 2020 08 11;109:56-62. Epub 2020 Mar 11.

Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.

Background: Mutations in the X-linked gene WDR45 cause neurodegeneration with brain iron accumulation type 5. Global developmental delay occurs at an early age with slow progression to dystonia, parkinsonism, and dementia due to progressive iron accumulation in the brain.

Methods: We present 17 new cases and reviewed 106 reported cases of neurodegeneration with brain iron accumulation type 5. Detailed information related to developmental history and key time to event measures was collected.

Results: Within this cohort, there were 19 males. Most individuals were molecularly diagnosed by whole-exome testing. Overall 10 novel variants were identified across 11 subjects. All individuals were affected by developmental delay, most prominently in verbal skills. Most individuals experienced a decline in motor and cognitive skills. Although most individuals were affected by seizures, the spectrum ranged from provoked seizures to intractable epilepsy. The imaging findings varied as well, often evolving over time. The classic iron accumulation in the globus pallidus and substantia nigra was noted in half of our cohort and was associated with older age of image acquisition, whereas myelination abnormalities were associated with younger age.

Conclusions: WDR45 mutations lead to a progressive and evolving disorder whose diagnosis is often delayed. Developmental delay and seizures predominate in early childhood, followed by a progressive decline of neurological function. There is variable expressivity in the clinical phenotypes of individuals with WDR45 mutations, suggesting that this gene should be considered in the diagnostic evaluation of children with myelination abnormalities, iron deposition, developmental delay, and epilepsy depending on the age at evaluation.
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http://dx.doi.org/10.1016/j.pediatrneurol.2020.03.005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7387198PMC
August 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

Chromatin remodeling dysfunction extends the etiological spectrum of schizophrenia: a case report.

BMC Med Genet 2020 01 8;21(1):10. Epub 2020 Jan 8.

Institut Neuromyogène, métabolisme énergétique et développement durable, CNRS UMR 5310, INSERM U1217, Université de Lyon, Université Claude Bernard Lyon 1, Lyon, France.

Background: The role of deleterious copy number variations in schizophrenia is well established while data regarding pathogenic variations remain scarce. We report for the first time a case of schizophrenia in a child with a pathogenic mutation of the chromodomain helicase DNA binding protein 2 (CHD2) gene.

Case Presentation: The proband was the second child of unrelated parents. Anxiety and sleep disorders appeared at the age of 10 months. He presented febrile seizures and, at the age of 8, two generalized tonic-clonic seizures. At the age of 10, emotional withdrawal emerged, along with a flat affect, disorganization and paranoid ideation, without seizures. He began to talk and giggle with self. Eventually, the patient presented daily auditory and visual hallucinations. The diagnosis of childhood onset schizophrenia (DSM V) was then evoked. Brain imaging was unremarkable. Wakefulness electroencephalography showed a normal background and some bilateral spike-wave discharges that did not explain the psychosis features. A comparative genomic hybridization array (180 K, Agilent, Santa Clara, CA, USA) revealed an 867-kb 16p13.3 duplication, interpreted as a variant of unknown significance confirmed by a quantitative PCR that also showed its maternal inheritance. Risperidone (1,5 mg per day), led to clinical improvement. At the age of 11, an explosive relapse of epilepsy occurred with daily seizures of various types. The sequencing of a panel for monogenic epileptic disorders and Sanger sequencing revealed a de novo pathogenic heterozygous transition in CHD2 (NM_001271.3: c.4003G > T).

Conclusions: This case underlines that schizophrenia may be, sometimes, underpinned by a Mendelian disease. It addresses the question of systematic genetic investigations in the presence of warning signs such as a childhood onset of the schizophrenia or a resistant epilepsy. It points that, in the absence of pathogenic copy number variation, the investigations should also include a search for pathogenic variations, which means that some of the patients with schizophrenia should benefit from Next Generation Sequencing tools. Last but not least, CHD2 encodes a member of the chromodomain helicase DNA-binding (CHD) family involved in chromatin remodeling. This observation adds schizophrenia to the phenotypic spectrum of chromodomain remodeling disorders, which may lead to innovative therapeutic approaches.
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http://dx.doi.org/10.1186/s12881-019-0946-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6950831PMC
January 2020

Infantile-Onset Paroxysmal Movement Disorder and Episodic Ataxia Associated with a TBC1D24 Mutation.

Neuropediatrics 2019 10 21;50(5):308-312. Epub 2019 Jun 21.

Pediatric Neurology, Child and Adolescent Department, University Hospitals, Geneva, Switzerland.

Mutations that disrupt the presynaptic protein have been implicated in various neurological disorders including epilepsy, chronic encephalopathy, DOORS (deafness, onychodystrophy, osteodystrophy, mental retardation, and seizures) syndrome, nonsyndromic hearing loss, and myoclonus. We present the case of a 22-month-old male with infantile-onset paroxysmal episodes of facial and limb myoclonus. The episodes were linked to biallelic variants in exon 2 of the gene that lead to amino acid changes (c.304C >T/p.Pro102Ser and c.410T > C/p.Val137Ala), each variant being inherited from a parent. Follow-up imaging in adolescence revealed widened right cerebellar sulci. We discuss the evolving landscape of associated phenotypes; this case adds to a growing body of evidence linking this gene to movement disorders in children.
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http://dx.doi.org/10.1055/s-0039-1688410DOI Listing
October 2019

Experience of follow-up, quality of life, and transition from pediatric to adult healthcare of patients with tuberous sclerosis complex.

Epilepsy Behav 2019 07 9;96:23-27. Epub 2019 May 9.

Department of Pediatric Neurology, Reference Centre for Rare Epilepsies, Necker-Enfants Malades, AP-HP, Paris, France; Laboratory of Translational Research for Neurological Disorders, INSERM UMR 1163, Imagine Institute, Paris, France; Université Paris Descartes -Sorbonne Paris Cité, Imagine Institute, Paris, France. Electronic address:

Introduction: Tuberous sclerosis complex (TSC) is a multisystemic genetic disease with high clinical variability and age-related manifestations. These characteristics add to the complexity of transition to adulthood. This study aimed to explore the perception of medical follow-up and transition experience in a large group of patients with TSC who presented epilepsy in childhood.

Method: This multicenter French study included patients with TSC aged 18 years or older who developed epilepsy before the age of 16 years. A questionnaire specifically designed for the study explored patients' opinion through 270 questions covering different aspects of their social, familial, professional, and medical courses.

Results: The questionnaire was sent to 72 patients, and 60 patients were included in the study (83% response rate) with a mean age of 32 years (18-55 years). Cognitive impairment was present in 80% of patients, and half of questionnaires were completed by the family. Pediatric care was coordinated by the child neurologist and was more regular and multidisciplinary than adult care. Epilepsy had the best follow-up followed by renal issues. Unmet needs were identified for psychiatric and behavioral disorders, both in children and adults. Respondents considered the help in achieving autonomy better in adult care. Only 50% of patients with a normal intellectual development had clear knowledge about their disease and the need for a regular monitoring. Two-thirds of respondents estimated that they had a transition experience between 16.5 and 21-year-old, considered as good in 60% of them. Seventy percent felt continuity between pediatric and adult care, and only 3% of respondents felt that their care would have been better if they were still followed in pediatric healthcare system. The change of care structure and/or caregivers was the most stressful factor during transition and transfer.

Conclusion: This study highlights persistent issues in the regularity and coordination of the follow-up of patients with TSC despite established international guidelines. Although most patients had a positive transition experience, there is still an urgent need to optimize transition programs. This would be essential to maintain care continuity between pediatric and adult health systems, especially for patients with TSC with epilepsy and high rate of cognitive and psychiatric impairments.
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http://dx.doi.org/10.1016/j.yebeh.2019.04.027DOI Listing
July 2019

Loss of the sphingolipid desaturase DEGS1 causes hypomyelinating leukodystrophy.

J Clin Invest 2019 03 11;129(3):1240-1256. Epub 2019 Feb 11.

Department of Clinical Genomics and.

Sphingolipid imbalance is the culprit in a variety of neurological diseases, some affecting the myelin sheath. We have used whole-exome sequencing in patients with undetermined leukoencephalopathies to uncover the endoplasmic reticulum lipid desaturase DEGS1 as the causative gene in 19 patients from 13 unrelated families. Shared features among the cases include severe motor arrest, early nystagmus, dystonia, spasticity, and profound failure to thrive. MRI showed hypomyelination, thinning of the corpus callosum, and progressive thalamic and cerebellar atrophy, suggesting a critical role of DEGS1 in myelin development and maintenance. This enzyme converts dihydroceramide (DhCer) into ceramide (Cer) in the final step of the de novo biosynthesis pathway. We detected a marked increase of the substrate DhCer and DhCer/Cer ratios in patients' fibroblasts and muscle. Further, we used a knockdown approach for disease modeling in Danio rerio, followed by a preclinical test with the first-line treatment for multiple sclerosis, fingolimod (FTY720, Gilenya). The enzymatic inhibition of Cer synthase by fingolimod, 1 step prior to DEGS1 in the pathway, reduced the critical DhCer/Cer imbalance and the severe locomotor disability, increasing the number of myelinating oligodendrocytes in a zebrafish model. These proof-of-concept results pave the way to clinical translation.
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http://dx.doi.org/10.1172/JCI123959DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6391109PMC
March 2019

Exome sequencing in congenital ataxia identifies two new candidate genes and highlights a pathophysiological link between some congenital ataxias and early infantile epileptic encephalopathies.

Genet Med 2019 03 12;21(3):553-563. Epub 2018 Jul 12.

Centre de Référence Maladies Rares "Malformations et Maladies Congénitales du Cervelet", Paris-Lyon-Lille, France.

Purpose: To investigate the genetic basis of congenital ataxias (CAs), a unique group of cerebellar ataxias with a nonprogressive course, in 20 patients from consanguineous families, and to identify new CA genes.

Methods: Singleton -exome sequencing on these 20 well-clinically characterized CA patients. We first checked for rare homozygous pathogenic variants, then, for variants from a list of genes known to be associated with CA or very early-onset ataxia, regardless of their mode of inheritance. Our replication cohort of 180 CA patients was used to validate the new CA genes.

Results: We identified a causal gene in 16/20 families: six known CA genes (7 patients); four genes previously implicated in another neurological phenotype (7 patients); two new candidate genes (2 patients). Despite the consanguinity, 4/20 patients harbored a heterozygous de novo pathogenic variant.

Conclusion: Singleton exome sequencing in 20 consanguineous CA families led to molecular diagnosis in 80% of cases. This study confirms the genetic heterogeneity of CA and identifies two new candidate genes (PIGS and SKOR2). Our work illustrates the diversity of the pathophysiological pathways in CA, and highlights the pathogenic link between some CA and early infantile epileptic encephalopathies related to the same genes (STXBP1, BRAT1, CACNA1A and CACNA2D2).
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http://dx.doi.org/10.1038/s41436-018-0089-2DOI Listing
March 2019

Early-onset encephalopathy with paroxysmal movement disorders and epileptic seizures without hemiplegic attacks: About three children with novel ATP1A3 mutations.

Brain Dev 2018 Oct 31;40(9):768-774. Epub 2018 May 31.

Centre de Référence Déficience Intellectuelle de Causes Rares, Paris, France; APHP, Service de Neurologie Pédiatrique, Hôpital Armand Trousseau, Paris, France; APHP, Centre de Référence des Mouvements Anormaux de l'Enfant, Hôpital Armand Trousseau, Paris, France; Sorbonne Université, GRC n°19, Pathologies Congénitales du Cervelet-LeucoDystrophies, AP-HP, Hôpital Armand Trousseau, F-75012 Paris, France. Electronic address:

Objective: Heterozygous mutations in the ATP1A3 gene are responsible for various neurological disorders, ranging from early-onset alternating hemiplegia of childhood to adult-onset dystonia-parkinsonism. Next generation sequencing allowed the description of other phenotypes, including early-onset epileptic encephalopathy in two patients. We report on three more patients carrying ATP1A3 mutations with a close phenotype and discuss the relationship of this phenotype to alternating hemiplegia of childhood.

Methods: The patients' DNA underwent next generation sequencing. A retrospective analysis of clinical case records is reported.

Results: Each of the three patients had an unreported heterozygous de novo sequence variant in ATP1A3. These patients shared a similar phenotype characterized by early-onset attacks of movement disorders, some of which proved to be epileptic, and severe developmental delay. (Hemi)plegic attacks had not been considered before genetic testing.

Significance: Together with the two previously reported cases, our patients confirm that ATP1A3 mutations are associated with a phenotype combining features of early-onset encephalopathy, epilepsy and dystonic fits, as in the most severe forms of alternating hemiplegia of childhood, but in which (hemi)plegic attacks are absent or only suspected retrospectively.
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http://dx.doi.org/10.1016/j.braindev.2018.05.008DOI Listing
October 2018

Outcome of isolated agenesis of the corpus callosum: A population-based prospective study.

Eur J Paediatr Neurol 2018 Jan 5;22(1):82-92. Epub 2017 Sep 5.

Université de Lyon, F-69008 Lyon, France; Radiologie pédiatrique et médecine fœtale, Hôpital Femme Mère Enfant, F-69677 Bron, France.

Objectives: Neurodevelopmental outcome of apparently isolated agenesis of the corpus callosum (ACC) remains a major concern with uncertain prognosis. Despite "normal" IQ reported in a majority of patients, the rates of learning disabilities and severe outcome (ranging from 0% to 20%) are not clearly established.

Methods: A large population-based series was investigated based on a longitudinal follow-up until school age, using Wechsler Intelligence scales at 3, 5, and 7 years.

Results: Fifty women were referred to a tertiary referral unit for an "apparently" isolated ACC confirmed by ultrasound, foetal MRI, and karyotyping or array CGH. Twelve pregnancies were terminated, one foetus died in utero, one pregnancy outcome was unknown, and 36 babies were born. Two were lost to follow-up. Thirty-four children could be classified into three groups. Group 1 comprised two children (6%) with severe intellectual disability (one Mowat-Wilson syndrome and one ASD). Group 2 comprised 10 children (29%) who had learning disabilities and borderline intellectual functioning (VIQ and/or PIQ scores >70 and <85); three patients had hypopituitarism with additional MRI anomalies revealed after birth. Group 3 comprised 22 children (65%) who had both VIQ and PIQ >85 (-1 SD) with a normal school level. Longitudinal follow-up revealed weaker PIQ in younger children which improved with age.

Conclusion: Our data indicate that intellectual ability is normal (IQ > 85) in approximately two thirds and borderline in just over a quarter of patients. However, a low risk of severe cognitive impairment exists, and this information should be shared with couples during prenatal counselling.
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http://dx.doi.org/10.1016/j.ejpn.2017.08.003DOI Listing
January 2018

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

Copy Number Variations Found in Patients with a Corpus Callosum Abnormality and Intellectual Disability.

J Pediatr 2017 06 8;185:160-166.e1. Epub 2017 Mar 8.

APHP, GH Pitié Salpêtrière, Department of genetics, unit of medical genetics, reference center for intellectual disabilities of rare causes, Paris, France; GRC Intellectual Disability and Autism, UPMC, Paris, France; Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, Inserm U 1127, CNRS UMR 7225, ICM, Paris, France; APHP, Hôpital Armand-Trousseau, Department of genetics, Division of clinical genetics, Paris, France.

Objective: To evaluate the role that chromosomal micro-rearrangements play in patients with both corpus callosum abnormality and intellectual disability, we analyzed copy number variations (CNVs) in patients with corpus callosum abnormality/intellectual disability STUDY DESIGN: We screened 149 patients with corpus callosum abnormality/intellectual disability using Illumina SNP arrays.

Results: In 20 patients (13%), we have identified at least 1 CNV that likely contributes to corpus callosum abnormality/intellectual disability phenotype. We confirmed that the most common rearrangement in corpus callosum abnormality/intellectual disability is inverted duplication with terminal deletion of the 8p chromosome (3.2%). In addition to the identification of known recurrent CNVs, such as deletions 6qter, 18q21 (including TCF4), 1q43q44, 17p13.3, 14q12, 3q13, 3p26, and 3q26 (including SOX2), our analysis allowed us to refine the 2 known critical regions associated with 8q21.1 deletion and 19p13.1 duplication relevant for corpus callosum abnormality; report a novel 10p12 deletion including ZEB1 recently implicated in corpus callosum abnormality with corneal dystrophy; and) report a novel pathogenic 7q36 duplication encompassing SHH. In addition, 66 variants of unknown significance were identified in 57 patients encompassed candidate genes.

Conclusions: Our results confirm the relevance of using microarray analysis as first line test in patients with corpus callosum abnormality/intellectual disability.
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http://dx.doi.org/10.1016/j.jpeds.2017.02.023DOI Listing
June 2017

Efficacy of a ketogenic diet in resistant myoclono-astatic epilepsy: A French multicenter retrospective study.

Epilepsy Res 2017 03 20;131:64-69. Epub 2017 Feb 20.

Hôpital Universitaire de Strasbourg, Centre de Référence des Epilepsies Rares, France. Electronic address:

Objective: Recent studies have suggested that the early introduction of a ketogenic diet (KD) could improve seizure control in myoclono-astatic epilepsy (MAE). This multicenter study sought to identify the benefits of KD use on seizure control and epilepsy and on developmental outcomes in children with resistant MAE.

Methods: Fifty children who were diagnosed with severe MAE in the French network of Reference Centers for Rare Epilepsies and who were treated with KD between 2000 and 2013 were included in this study. The seizure frequency and EEG recordings were assessed two weeks before KD introduction, 2 and 6 months after, and during the last follow-up, which also included an assessment of developmental outcome.

Results: Patients had a median follow up of 52 months (range 13-136) and received 4.3 antiepileptic drugs [2-9] before KD introduction. Fifty-four percent (54%) of our patients were seizure-free after 6 months of KD or more, and 86% experienced more than a 70% seizure reduction after 2 months of KD. Forty-four percent (44%) of them had a clear benefit of early KD treatment (after four AEDs failed). Early KD treatment did not result in a greater seizure reduction (p=0.055), but significantly resulted in remission (p<0.028). Fifty percent of patients with resistant MAE had normal development outcomes. Earlier KD treatment, after three AEDs failed, was correlated with a better cognitive outcome (p<0.01).

Significance: Early introduction of KD treatment in resistant MAE has a strong, persistent anticonvulsant effect with long-term remission and better cognitive outcomes.
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http://dx.doi.org/10.1016/j.eplepsyres.2017.02.005DOI Listing
March 2017

Novel homozygous missense variant of GRIN1 in two sibs with intellectual disability and autistic features without epilepsy.

Eur J Hum Genet 2017 02 4;25(3):376-380. Epub 2017 Jan 4.

Department of Genetics, Lyon University Hospitals, Lyon, France.

We report on two consanguineous sibs affected with severe intellectual disability and autistic features due to a homozygous missense variant of GRIN1. Massive parallel sequencing was performed using a gene panel including 450 genes related to intellectual disability and autism spectrum disorders. We found a homozygous missense variation of GRIN1 (c.679G>C; p.(Asp227His)) in the two affected sibs, which was inherited from both unaffected heterozygous parents. Heterozygous variants of GRIN1, encoding the GluN1 subunit of the NMDA receptor, have been reported in patients with neurodevelopmental disorders including epileptic encephalopathy, severe intellectual disability, and movement disorders. The p.(Asp227His) variant is located in the same aminoterminal protein domain as the recently published p.(Arg217Trp), which was found at the homozygous state in two patients with a similar phenotype of severe intellectual disability and autistic features but without epilepsy. In silico predictions were consistent with a deleterious effect. The present findings further expand the clinical spectrum of GRIN1 variants and support the existence of hypomorphic variants causing severe neurodevelopmental impairment with autosomal recessive inheritance.
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http://dx.doi.org/10.1038/ejhg.2016.163DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5315503PMC
February 2017

Autosomal-Recessive Mutations in AP3B2, Adaptor-Related Protein Complex 3 Beta 2 Subunit, Cause an Early-Onset Epileptic Encephalopathy with Optic Atrophy.

Am J Hum Genet 2016 Dec 23;99(6):1368-1376. Epub 2016 Nov 23.

Department of Paediatrics, Faculty of Medicine, Jordan University, Amman 11942, Jordan.

Early-onset epileptic encephalopathy (EOEE) represents a heterogeneous group of severe disorders characterized by seizures, interictal epileptiform activity with a disorganized electroencephalography background, developmental regression or retardation, and onset before 1 year of age. Among a cohort of 57 individuals with epileptic encephalopathy, we ascertained two unrelated affected individuals with EOEE associated with developmental impairment and autosomal-recessive variants in AP3B2 by means of whole-exome sequencing. The targeted sequencing of AP3B2 in 86 unrelated individuals with EOEE led to the identification of an additional family. We gathered five additional families with eight affected individuals through the Matchmaker Exchange initiative by matching autosomal-recessive mutations in AP3B2. Reverse phenotyping of 12 affected individuals from eight families revealed a homogeneous EOEE phenotype characterized by severe developmental delay, poor visual contact with optic atrophy, and postnatal microcephaly. No spasticity, albinism, or hematological symptoms were reported. AP3B2 encodes the neuron-specific subunit of the AP-3 complex. Autosomal-recessive variations of AP3B1, the ubiquitous isoform, cause Hermansky-Pudlak syndrome type 2. The only isoform for the δ subunit of the AP-3 complex is encoded by AP3D1. Autosomal-recessive mutations in AP3D1 cause a severe disorder cumulating the symptoms of the AP3B1 and AP3B2 defects.
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http://dx.doi.org/10.1016/j.ajhg.2016.10.009DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5142104PMC
December 2016

TBC1D24 genotype-phenotype correlation: Epilepsies and other neurologic features.

Neurology 2016 07 8;87(1):77-85. Epub 2016 Jun 8.

Objective: To evaluate the phenotypic spectrum associated with mutations in TBC1D24.

Methods: We acquired new clinical, EEG, and neuroimaging data of 11 previously unreported and 37 published patients. TBC1D24 mutations, identified through various sequencing methods, can be found online (http://lovd.nl/TBC1D24).

Results: Forty-eight patients were included (28 men, 20 women, average age 21 years) from 30 independent families. Eighteen patients (38%) had myoclonic epilepsies. The other patients carried diagnoses of focal (25%), multifocal (2%), generalized (4%), and unclassified epilepsy (6%), and early-onset epileptic encephalopathy (25%). Most patients had drug-resistant epilepsy. We detail EEG, neuroimaging, developmental, and cognitive features, treatment responsiveness, and physical examination. In silico evaluation revealed 7 different highly conserved motifs, with the most common pathogenic mutation located in the first. Neuronal outgrowth assays showed that some TBC1D24 mutations, associated with the most severe TBC1D24-associated disorders, are not necessarily the most disruptive to this gene function.

Conclusions: TBC1D24-related epilepsy syndromes show marked phenotypic pleiotropy, with multisystem involvement and severity spectrum ranging from isolated deafness (not studied here), benign myoclonic epilepsy restricted to childhood with complete seizure control and normal intellect, to early-onset epileptic encephalopathy with severe developmental delay and early death. There is no distinct correlation with mutation type or location yet, but patterns are emerging. Given the phenotypic breadth observed, TBC1D24 mutation screening is indicated in a wide variety of epilepsies. A TBC1D24 consortium was formed to develop further research on this gene and its associated phenotypes.
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http://dx.doi.org/10.1212/WNL.0000000000002807DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4932231PMC
July 2016

Genetic and neurodevelopmental spectrum of SYNGAP1-associated intellectual disability and epilepsy.

J Med Genet 2016 08 17;53(8):511-22. Epub 2016 Mar 17.

Svt. Luka's Institute of Child Neurology and Epilepsy, Moscow, Russia.

Objective: We aimed to delineate the neurodevelopmental spectrum associated with SYNGAP1 mutations and to investigate genotype-phenotype correlations.

Methods: We sequenced the exome or screened the exons of SYNGAP1 in a total of 251 patients with neurodevelopmental disorders. Molecular and clinical data from patients with SYNGAP1 mutations from other centres were also collected, focusing on developmental aspects and the associated epilepsy phenotype. A review of SYNGAP1 mutations published in the literature was also performed.

Results: We describe 17 unrelated affected individuals carrying 13 different novel loss-of-function SYNGAP1 mutations. Developmental delay was the first manifestation of SYNGAP1-related encephalopathy; intellectual disability became progressively obvious and was associated with autistic behaviours in eight patients. Hypotonia and unstable gait were frequent associated neurological features. With the exception of one patient who experienced a single seizure, all patients had epilepsy, characterised by falls or head drops due to atonic or myoclonic seizures, (myoclonic) absences and/or eyelid myoclonia. Triggers of seizures were frequent (n=7). Seizures were pharmacoresistant in half of the patients. The severity of the epilepsy did not correlate with the presence of autistic features or with the severity of cognitive impairment. Mutations were distributed throughout the gene, but spared spliced 3' and 5' exons. Seizures in patients with mutations in exons 4-5 were more pharmacoresponsive than in patients with mutations in exons 8-15.

Conclusions: SYNGAP1 encephalopathy is characterised by early neurodevelopmental delay typically preceding the onset of a relatively recognisable epilepsy comprising generalised seizures (absences, myoclonic jerks) and frequent triggers.
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http://dx.doi.org/10.1136/jmedgenet-2015-103451DOI Listing
August 2016

Epilepsy in young Tsc1(+/-) mice exhibits age-dependent expression that mimics that of human tuberous sclerosis complex.

Epilepsia 2016 Apr 13;57(4):648-59. Epub 2016 Feb 13.

INSERM U1129 "Infantile Epilepsies and Brain Plasticity", Paris, France.

Objective: To describe the epileptic phenotype of Tsc1(+/-) mice pups in comparison with age-related seizures in human tuberous sclerosis complex (TSC).

Methods: Tsc1(+/-) and control mice underwent intracranial electroencephalography (EEG) recording at postnatal ages (P)8 to P33, with linear silicon probe implanted in the somatosensory cortex of one or both hemispheres for 8-24 h. Ictal events were classified visually by independent analyzers; distinct EEG patterns were related to age and analyzed to quantify field potential characteristics and signal dynamics between hemispheres. We collected retrospectively 20 infants with prenatally diagnosed TSC and EEG before seizure onset, and analyzed the electroclinical course of epilepsy, taking into account a first-line treatment by vigabatrin.

Results: Spontaneous seizures were disclosed in 55% of Tsc1(+/-) mice at P9-18. Three ictal patterns were identified: from P9 to P12 "spike clusters" consisted of recurring large spikes without clinical correlate; "spasm-like" discharges dominated from P13 to P16 consisting of high amplitude large field potential superimposed with or followed by fast activity repeated every 2-10 s for at least 20 s, accompanied by rhythmic limb contractions; from P14 to P18 a "tonic-clonic like" pattern comprised rhythmic spikes of increasing amplitude with tonic-clonic movements. Early onset "spike clusters" were mainly unilateral, whereas "spasm-like" and "tonic-clonic like" patterns were bilateral. Interhemispheric propagation was significantly faster for "tonic-clonic like" than for "spasm-like" events. In infants diagnosed prenatally with TSC, clusters of sharp waves or spikes preceded the first seizure, and vigabatrin prevented the development of seizures. Patients treated after seizure onset developed spasms or focal seizures that were pharmacoresistant in 66.7% of cases.

Significance: Tsc1(+/-) mice pups exhibit an age-dependent seizure pattern sequence mimicking early human TSC epilepsy features. Spike clusters before seizure onset in TSC should be considered as a first stage of epilepsy reinforcing the concept of preventive antiepileptic therapy.
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http://dx.doi.org/10.1111/epi.13325DOI Listing
April 2016

Epileptic patients with de novo STXBP1 mutations: Key clinical features based on 24 cases.

Epilepsia 2015 Dec 29;56(12):1931-40. Epub 2015 Oct 29.

Pediatric Neurology Department, Timone Children Hospital, Marseille, France.

Objective: Mutations in the syntaxin binding protein 1 gene (STXBP1) have been associated mostly with early onset epileptic encephalopathies (EOEEs) and Ohtahara syndrome, with a mutation detection rate of approximately 10%, depending on the criteria of selection of patients. The aim of this study was to retrospectively describe clinical and electroencephalography (EEG) features associated with STXBP1-related epilepsies to orient molecular screening.

Methods: We screened STXBP1 in a cohort of 284 patients with epilepsy associated with a developmental delay/intellectual disability and brain magnetic resonance imaging (MRI) without any obvious structural abnormality. We reported on patients with a mutation and a microdeletion involving STXBP1 found using array comparative genomic hybridization (CGH).

Results: We found a mutation of STXBP1 in 22 patients and included 2 additional patients with a deletion including STXBP1. In 22 of them, epilepsy onset was before 3 months of age. EEG at onset was abnormal in all patients, suppression-burst and multifocal abnormalities being the most common patterns. The rate of patients carrying a mutation ranged from 25% in Ohtahara syndrome to <5% in patients with an epilepsy beginning after 3 months of age. Epilepsy improved over time for most patients, with an evolution to West syndrome in half. Patients had moderate to severe developmental delay with normal head growth. Cerebellar syndrome with ataxic gait and/or tremor was present in 60%.

Significance: Our data confirm that STXBP1 mutations are associated with neonatal-infantile epileptic encephalopathies. The initial key features highlighted in the cohort of early epileptic patients are motor seizures either focal or generalized, abnormal initial interictal EEG, and normal head growth. In addition, we constantly found an ongoing moderate to severe developmental delay with normal head growth. Patients often had ongoing ataxic gait with trembling gestures. Altogether these features should help the clinician to consider STXBP1 molecular screening.
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http://dx.doi.org/10.1111/epi.13214DOI Listing
December 2015

A New Observation of an Atypical and Severe Variant of the Guillain-Barre Syndrome in a Child: Remaining Challenges for Diagnosis, Nosologic Classification, and Therapeutic Course.

Child Neurol Open 2015 Oct-Dec;2(4):2329048X15609053. Epub 2015 Oct 26.

Service de réanimation pédiatrique, Hôpital Femme Mère Enfant, HCL, Lyon, France.

Guillain-Barré syndrome is a rare acute polyradiculoneuropathy. Several variants and unusual presentations have been described, particularly in pediatrics. In most cases, making an early diagnosis is challenging due to the treatments that consist in the rapid administration of intravenous immunoglobulin or plasma exchange. The authors present the case of a 7-year-old boy with an atypical and severe axonal Guillain-Barré syndrome, associated with . When he was admitted, febrile respiratory failure was the main focus, and then he presented signs of acute polyneuropathy with cranial nerve palsy and brief hyperreflexia. Mechanical ventilation was required for 48 days as well as 2 cycles of intravenous immunoglobulin. The authors describe all the medical challenges that the authors encountered. This case highlights the fact that respiratory distress can be the main clinical symptom in children. This delays the establishment of a correct diagnosis, even more so when neurological manifestations are abundant and unusual.
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http://dx.doi.org/10.1177/2329048X15609053DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5417028PMC
October 2015

West syndrome caused by homozygous variant in the evolutionary conserved gene encoding the mitochondrial elongation factor GUF1.

Eur J Hum Genet 2016 07 21;24(7):1001-8. Epub 2015 Oct 21.

Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland.

West syndrome (WS), defined by the triad of infantile spasms, pathognomonic hypsarrhythmia and developmental regression, is a rare epileptic disease affecting about 1:3500 live births. To get better insights on the genetic of this pathology, we exome-sequenced the members of a consanguineous family affected with isolated WS. We identified a homozygous variant (c.1825G>T/p.(Ala609Ser)) in the GUF1 gene in the three affected siblings. GUF1 encodes a protein essential in conditions that counteract faithful protein synthesis: it is able to remobilize stuck ribosomes and transiently inhibit the elongation process to optimize protein synthesis. The variant identified in the WS family changes an alanine residue conserved in all eukaryotic organisms and positioned within the tRNA-binding moiety of this nuclear genome-encoded mitochondrial translational elongation factor. Yeast complementation assays show that the activity of GUF1(A609S) is modified in suboptimal environments. We suggest a new link between improper assembly of respiratory chain complexes and WS.
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http://dx.doi.org/10.1038/ejhg.2015.227DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5070883PMC
July 2016

The ketogenic diet can be used successfully in combination with corticosteroids for epileptic encephalopathies.

Epilepsy Behav 2015 Jul 8;48:61-5. Epub 2015 Jun 8.

INSERM U1129 "Infantile Epilepsies and Brain Plasticity", Paris, France; University Paris Descartes, PRES Sorbonne Paris Cité, CEA, Gif sur Yvette, France; Fondation Ophtalmologique Rothschild, Paris, France.

Hormonal therapy or ketogenic diet often permits overcoming the challenging periods of many epileptic encephalopathies (West and Lennox-Gastaut syndromes and encephalopathy with continuous spike-waves in slow sleep), but relapse affects over 20% of patients. We report here a monocenter pilot series of 42 consecutive patients in whom we combined oral steroids with the ketogenic diet for corticosteroid-resistant or -dependent epileptic encephalopathy. We retrospectively evaluated the effect on seizure frequency, interictal spike activity, neuropsychological course, and steroid treatment course. Twenty-three patients had West syndrome (WS), 13 had encephalopathy with continuous spike-waves in slow sleep (CSWS), and six others had miscellaneous epileptic encephalopathies. All patients succeeded to reach 0.8 to 1.6g/l ketone bodies in the urine following the usual KD regimen. For at least 6 months, 14/42 responded to the addition of the ketogenic diet: 4/23 with WS, 8/13 with CSWS, and 2/6 with miscellaneous epileptic encephalopathies. The addition of the KD allowed withdrawing steroids in all responders. Among them, 10/15 had been patients with steroid-dependent epileptic encephalopathy and 4/27 patients with steroid-resistant epileptic encephalopathy. Therefore, the ketogenic diet can be used successfully in combination with corticosteroids for epileptic encephalopathies. Patients presenting with steroid-dependent CSWS seem to be the best candidates.
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http://dx.doi.org/10.1016/j.yebeh.2015.03.003DOI Listing
July 2015

Homozygous TBC1D24 mutation in two siblings with familial infantile myoclonic epilepsy (FIME) and moderate intellectual disability.

Epilepsy Res 2015 Mar 25;111:72-7. Epub 2015 Jan 25.

Department of Medical Genetics, Hospices Civils de Lyon, Lyon, France; Université Lyon 1, Lyon, France; Neurophysiology and Epilepsy Unit, Neurological Hospital P. Wertheimer, Hospices Civils de Lyon, Lyon, France. Electronic address:

Mutations in the TBC1D24 gene were first reported in an Italian family with a unique epileptic phenotype consisting of drug-responsive, early-onset idiopathic myoclonic seizures. Patients presented with isolated bilateral or focal myoclonia, which could evolve to long-lasting attacks without loss of consciousness, with a peculiar reflex component, and were associated with generalized tonic-clonic seizures. This entity was named "familial infantile myoclonic epilepsy" (FIME). More recently, TBC1D24 mutations have been shown to cause a variable range of disorders, including epilepsy of various seizure types and severity, non-syndromic deafness, and DOORS syndrome. We report on the electro-clinical features of two brothers, born to first-cousin parents, affected with infantile-onset myoclonic epilepsy. The peculiar epileptic presentation prompted us to perform direct sequencing of the TBC1D24 gene. The patients had very early onset of focal myoclonic fits with variable topography, lasting a few minutes to several hours, without loss of consciousness, which frequently evolved to generalized myoclonus or myoclonic status. Reflex myoclonia were noticed in one patient. Neurological outcome was marked by moderate intellectual disability. Despite the high frequency of seizures, repeated EEG recordings showed normal background rhythm and rare interictal spikes and waves. We found a homozygous missense mutation, c.457G>A/p.Glu153Lys, in the two affected brothers. This observation combined with recent data from the literature, suggest that mutations in TBCD24 cause a pathological continuum, with FIME at the "benign" end and severe drug-refractory epileptic encephalopathy on the severe end. Early-onset myoclonic epilepsy with focal and generalized myoclonic seizures is a common characteristic of this continuum.
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http://dx.doi.org/10.1016/j.eplepsyres.2015.01.008DOI Listing
March 2015

Molecular characterization of a cohort of 73 patients with infantile spasms syndrome.

Eur J Med Genet 2015 Feb 11;58(2):51-8. Epub 2014 Dec 11.

CRNL, CNRS UMR 5292, INSERM U1028, Lyon, France; Department of Genetics, Lyon University Hospital, Lyon, France; Claude Bernard Lyon I University, Lyon, France. Electronic address:

Infantile Spasms syndrome (ISs) is a characterized by epileptic spasms occurring in clusters with an onset in the first year of life. West syndrome represents a subset of ISs that associates spasms in clusters, a hypsarrhythmia EEG pattern and a developmental arrest or regression. Aetiology of ISs is widely heterogeneous including many genetic causes. Many patients, however, remain without etiological diagnosis, which is critical for prognostic purpose and genetic counselling. In the present study, we performed genetic screening of 73 patients with different types of ISs by array-CGH and molecular analysis of 5 genes: CDKL5, STXBP1, KCNQ2, and GRIN2A, whose mutations cause different types of epileptic encephalopathies, including ISs, as well as MAGI2, which was suggested to be related to a subset of ISs. In total, we found a disease-causing mutation or CNV (Copy Number Variation) in 15% of the patients. These included 6 point mutations found in CDKL5 (n = 3) and STXBP1 (n = 3), 3 microdeletions (10 Mb in 2q24.3, 3.2 Mb in 5q14.3 including the region upstream to MEF2C, and 256 kb in 9q34 disrupting EHMT1), and 2 microduplications (671 kb in 2q24.3 encompassing SCN2A, and 11.93 Mb in Xq28). In addition, we discuss 3 CNVs as potential risk factors, including one 16p12.1 deletion, one intronic deletion of the NEDD4 gene, and one intronic deletion of CALN1 gene. The present findings highlight the efficacy of combined cytogenetic and targeted mutation screening to improve the diagnostic yield in patient with ISs.
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http://dx.doi.org/10.1016/j.ejmg.2014.11.007DOI Listing
February 2015

DEPDC5 mutations in families presenting as autosomal dominant nocturnal frontal lobe epilepsy.

Neurology 2014 Jun 9;82(23):2101-6. Epub 2014 May 9.

From the Department of Neurology (F.P.), and Service of Genetic Medicine (S.E.A.), University Hospitals of Geneva; Department of Genetic Medicine and Development (P.M.), and iGE3, Institute of Genetics and Genomics of Geneva (S.E.A.), University of Geneva, Switzerland; Institut national de la santé et de la recherche médicale (INSERM) (V.N., S.I., C.D., I.A.-G., M.V., M.B., E.L., S.B.), U1127, ICM, Paris, F-75013 Paris; Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, F-75013 Paris (V.N., S.I., C.D., I.A.-G., M.V., M.B., E.L., S.B.), Paris; CNRS (V.N., S.I., C.D., I.A.-G., M.V., M.B., E.L., S.B.), UMR7225, Hôpital de la Pitié-Salpêtrière, Paris; Epilepsy Unit (V.N., I.A.-G., M.V., M.B.), ICM, Paris, F-75013 Paris, France (V.N., S.I., C.D., I.A.-G., M.V., M.B., E.L., S.B.), and Département de Génétique et de Cytogénétique (C.D., E.L.), AP-HP Groupe hospitalier Pitié-Salpêtrière, Paris; Epilepsy, Sleep and Pediatric Neurophysiology (J.d.B.), University Hospitals of Lyon; Hospices Civils de Lyon (D.V.), HFME, centre de référence déficiences intellectuelles de causes rares et sclérose tubéreuse de Bourneville, Bron, France; Neurogenetics Group (S.W., A.S., P.D.J.), 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; Algemeen Stedelijk Ziekenhuis (E.F.), Aalst; Division of Neurology (P.D.J.), Antwerp University Hospital, Antwerp University, Belgium; Centre hospitalier général de Valence (M.V.R.); Department of Medical Genetics (G.L.), Hospices Civils de Lyon; Claude Bernard Lyon I University (G.L.); CRNL (G.L.), CNRS UMR 5292, INSERM U1028, Lyon; Centre de référence épilepsies rares et Sclérose tubéreuse de Bourneville (I.A.-G., M.B.); Genotyping and Sequencing Platform, ICM (E.M.), and DNA and Cell Bank (P.C.), Hôpital Pitié-Salpêtrière, Paris, France; Department of Surge

Objective: To study the prevalence of DEPDC5 mutations in a series of 30 small European families with a phenotype compatible with autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE).

Methods: Thirty unrelated families referred with ADNFLE were recruited in France, Italy, Germany, Belgium, and Norway. Whole-exome sequencing was performed in 10 probands and direct sequencing of the DEPDC5 coding sequence in 20 probands. Testing for nonsense-mediated messenger RNA decay (NMD) was performed in lymphoblastic cells.

Results: Exome sequencing revealed a splice acceptor mutation (c.2355-2A>G) in DEPDC5 in the proband of a German family. In addition, 3 nonsense DEPDC5 mutations (p.Arg487*, p.Arg1087*, and p.Trp1369*) were detected in the probands of 2 French and one Belgian family. The nonsense mutations p.Arg487* and p.Arg1087* were targeted by NMD, leading to the degradation of the mutated transcripts. At the clinical level, 78% of the patients with DEPDC5 mutations were drug resistant.

Conclusions: DEPDC5 loss-of-function mutations were found in 13% of the families with a presentation of ADNFLE. The rate of drug resistance was high in patients with DEPDC5 mutations. Small ADNFLE pedigrees with DEPDC5 mutations might actually represent a part of the broader familial focal epilepsy with variable foci phenotype.
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http://dx.doi.org/10.1212/WNL.0000000000000488DOI Listing
June 2014

De novo mutations in HCN1 cause early infantile epileptic encephalopathy.

Nat Genet 2014 Jun 20;46(6):640-5. Epub 2014 Apr 20.

1] Neurogenetics Group, Department of Molecular Genetics, VIB, Antwerp, Belgium. [2] Laboratory of Neurogenetics, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium.

Hyperpolarization-activated, cyclic nucleotide-gated (HCN) channels contribute to cationic Ih current in neurons and regulate the excitability of neuronal networks. Studies in rat models have shown that the Hcn1 gene has a key role in epilepsy, but clinical evidence implicating HCN1 mutations in human epilepsy is lacking. We carried out exome sequencing for parent-offspring trios with fever-sensitive, intractable epileptic encephalopathy, leading to the discovery of two de novo missense HCN1 mutations. Screening of follow-up cohorts comprising 157 cases in total identified 4 additional amino acid substitutions. Patch-clamp recordings of Ih currents in cells expressing wild-type or mutant human HCN1 channels showed that the mutations had striking but divergent effects on homomeric channels. Individuals with mutations had clinical features resembling those of Dravet syndrome with progression toward atypical absences, intellectual disability and autistic traits. These findings provide clear evidence that de novo HCN1 point mutations cause a recognizable early-onset epileptic encephalopathy in humans.
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http://dx.doi.org/10.1038/ng.2952DOI Listing
June 2014
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