Minimum effective sodium valproate dose in genetic generalized epilepsies.

INTRODUCTION: Sodium valproate (VPA) is the most effective antiseizure medication (ASM) in genetic generalized epilepsies (GGEs). However, the frequent adverse effects and the high risk inflicted on the exposed offspring make it imperative to search for the lowest daily VPA dose able to control seizures for most patients. In the current published series, the VPA value of <1000 mg was the most adopted. OBJECTIVE: This study aims to provide a cutoff VPA value below which a given daily dose can be considered a low dose in patients with GGEs. METHODS: This retrospective, observational cohort study included patients with clinical and electroencephalographic diagnoses of GGEs based on the ILAE criteria. Patients were followed up for at least two years using VPA in mono- or polytherapy. Clinical data, VPA dose, and associated ASMs were analyzed. Adverse effects were also evaluated. We related seizure control to VPA doses through uni- and multivariate statistical analyses. RESULTS: From 225 patients, 169 (75%) had good seizure control, with most (60%) receiving monotherapy. The cutoff daily VPA dose capable of distinguishing these patients from those without seizure control was up to 1000 mg (p = 0.006) in univariate analyses and up to 700 mg in multivariate analyses. For patients in polytherapy, the cutoff was up to 1750 mg and 1800 mg in uni- and multivariate analyses, respectively. CONCLUSIONS: The lowest daily VPA dose in monotherapy able to control seizures for most GGE patients was up to 700 mg, a value that can be used as a low dose criterion in studies assessing the therapeutic VPA ranges. Patients using higher VPA doses or in polytherapy present a lower probability of seizure control.

Revisiting the clinical impact of variants in EFHC1 in patients with different phenotypes of genetic generalized epilepsy.

The most common form of genetic generalized epilepsy (GGE) is juvenile myoclonic epilepsy (JME), which accounts for 5 to 10% of all epilepsy cases. The gene EFHC1 has been implicated as a putative cause of JME. However, it remains debatable whether testing for EFHC1 mutations should be included in the diagnostic epilepsy gene panels. To investigate the clinical utility of EFHC1 testing, we studied 125 individuals: 100 with JME and 25 with other GGEs. We amplified and sequenced all EFHC1 coding exons. Then, we predicted the pathogenicity or benign impact of the variants using the analyses proposed by the American College of Medical Genetics and Genomics (ACMG)/Association for Molecular Pathology (AMP). Mutation screening revealed 11 missense variants in 44 probands with JME (44%) and one of the seven individuals with generalized tonic-clonic seizures on awakening (14%). Six of the 11 variants (54%) were classified as 'benign,' and the remaining variants were considered variants of uncertain significance (VUS). There is currently a limitation to test for genes that predispose an individual to complex, nonmonogenic phenotypes. Thus, we show suggestive evidence that EFHC1 testing lacks a scientific foundation based on the disputed nature of the gene-disease relationship and should be currently limited to research purposes.

Sleepwalking and Sleep Paralysis: Prevalence in Colombian Families With Genetic Generalized Epilepsy.

BACKGROUND: Sleep deprivation commonly increases seizure frequency in patients with genetic generalized epilepsy, though it is unknown whether there is an increased prevalence of sleepwalking or sleep paralysis in genetic generalized epilepsy patients. Establishing this could provide insights into the bio-mechanisms or genetic architecture of both disorders. The aim of this study was to determine the prevalence of sleepwalking and sleep paralysis in a cohort of patients with genetic generalized epilepsy and their relatives in extended families. METHODS: A structured interview based on International League Against Epilepsy (ILAE) and International Classification of Sleep Disorders (ICSD-3) criteria was applied to 67 index cases and their relatives to determine genetic generalized epilepsy subtypes and assess the occurrence of sleepwalking or sleep paralysis. Bivariate analysis was performed using chi-square and Fisher exact tests. RESULTS: The prevalence of sleepwalking and sleep paralysis was 15.3% (95% confidence interval 12.1-18.9) and 11.7% (95% confidence interval 8.7-15.3), respectively. Unusually, no sleepwalkers were found among individuals displaying epilepsy with generalized tonic-clonic seizures. Approximately a quarter of the patients had either parasomnia or genetic generalized epilepsy. Over half the genetic generalized epilepsy families had at least 1 individual with sleepwalking, and more than 40% of the families had one individual with sleep paralysis. CONCLUSION: The prevalence of sleepwalking or sleep paralysis is reported for individuals with genetic generalized epilepsy and their relatives. The co-existence of either parasomnia in the genetic generalized epilepsy patients and the co-aggregation within their families let suggest that shared heritability and pathophysiological mechanisms exist between these disorders. We hypothesize that sleepwalking/sleep paralysis and genetic generalized epilepsy could be variable expression of genes in shared pathways.

Novel ANKRD11 gene mutation in an individual with a mild phenotype of KBG syndrome associated to a GEFS+ phenotypic spectrum: a case report.

BACKGROUND: KBG syndrome is a very rare autosomal dominant disorder, characterized by macrodontia, distinctive craniofacial findings, skeletal findings, post-natal short stature, and developmental delays, sometimes associated with seizures and EEG abnormalities. So far, there have been over 100 cases of KBG syndrome reported. CASE PRESENTATION: Here, we describe two sisters of a non-consanguineous family, both presenting generalized epilepsy with febrile seizures (GEFS+), and one with a more complex phenotype associated with mild intellectual disability, skeletal and dental anomalies. Whole exome sequencing (WES) analysis in all the family members revealed a heterozygous SCN9A mutation, p.(Lys655Arg), shared among the father and the two probands, and a novel de novo loss of function mutation in the ANKRD11 gene, p.(Tyr1715*), in the proband with the more complex phenotype. The reassessment of the phenotypic features confirmed that the patient fulfilled the proposed diagnostic criteria for KBG syndrome, although complicated by early-onset isolated febrile seizures. EEG abnormalities with or without seizures have been reported previously in some KBG cases. The shared variant, occurring in SCN9A, has been previously found in several individuals with GEFS+ and Dravet syndrome. CONCLUSIONS: This report describe a novel de novo variant in ANKRD11 causing a mild phenotype of KGB syndrome and further supports the association of monogenic pattern of SCN9A mutations with GEFS+. Our data expand the allelic spectrum of ANKRD11 mutations, providing the first Brazilian case of KBG syndrome. Furthermore, this study offers an example of how WES has been instrumental allowing us to better dissect the clinical phenotype under study, which is a multilocus variation aggregating in one proband, rather than a phenotypic expansion associated with a single genomic locus, underscoring the role of multiple rare variants at different loci in the etiology of clinical phenotypes making problematic the diagnostic path. The successful identification of the causal variant in a gene may not be sufficient, making it necessary to identify other variants that fully explain the clinical picture. The prevalence of blended phenotypes from multiple monogenic disorders is currently unknown and will require a systematic re-analysis of large WES datasets for proper diagnosis in daily practice.

Heterogeneous contribution of microdeletions in the development of common generalised and focal epilepsies.

BACKGROUND: Microdeletions are known to confer risk to epilepsy, particularly at genomic rearrangement 'hotspot' loci. However, microdeletion burden not overlapping these regions or within different epilepsy subtypes has not been ascertained. OBJECTIVE: To decipher the role of microdeletions outside hotspots loci and risk assessment by epilepsy subtype. METHODS: We assessed the burden, frequency and genomic content of rare, large microdeletions found in a previously published cohort of 1366 patients with genetic generalised epilepsy (GGE) in addition to two sets of additional unpublished genome-wide microdeletions found in 281 patients with rolandic epilepsy (RE) and 807 patients with adult focal epilepsy (AFE), totalling 2454 cases. Microdeletions were assessed in a combined and subtype-specific approaches against 6746 controls. RESULTS: When hotspots are considered, we detected an enrichment of microdeletions in the combined epilepsy analysis (adjusted p=1.06×10-6,OR 1.89, 95% CI 1.51 to 2.35). Epilepsy subtype-specific analyses showed that hotspot microdeletions in the GGE subgroup contribute most of the overall signal (adjusted p=9.79×10-12, OR 7.45, 95% CI 4.20-13.5). Outside hotspots , microdeletions were enriched in the GGE cohort for neurodevelopmental genes (adjusted p=9.13×10-3,OR 2.85, 95% CI 1.62-4.94). No additional signal was observed for RE and AFE. Still, gene-content analysis identified known (NRXN1, RBFOX1 and PCDH7) and novel (LOC102723362) candidate genes across epilepsy subtypes that were not deleted in controls. CONCLUSIONS: Our results show a heterogeneous effect of recurrent and non-recurrent microdeletions as part of the genetic architecture of GGE and a minor contribution in the aetiology of RE and AFE.

Efficacy and safety of a video-EEG protocol for genetic generalized epilepsies.

INTRODUCTION: Video-EEG has been used to characterize genetic generalized epilepsies (GGE). For best performance, sleep recording, photic stimulation, hyperventilation, and neuropsychological protocols are added to the monitoring. However, risks and benefits of these video-EEG protocols are not well established. The aim of this study was to analyze the efficacy and safety of a video-EEG neuropsychological protocol (VNPP) tailored for GGE and compare its value with that of routine EEG (R-EEG). METHODS: We reviewed the VNPP and R-EEG of patients with GGE. We considered confirmation of the clinical suspicion of a GGE syndrome and characterization of reflex traits as benefits; and falls, injuries, psychiatric and behavioral changes, generalized tonic-clonic (GTC) seizures, and status epilepticus (SE) as the main risks of the VNPP. RESULTS: The VNPPs of 113 patients were analyzed. The most common epileptic syndrome was juvenile myoclonic epilepsy (85.8%). The protocol confirmed a GGE syndrome in 97 patients and 62 had seizures. Sleep recording had a provocative effect in 51.2% of patients. The second task that showed highest efficacy was praxis (39.3%) followed by hyperventilation (31.3%). Among the risks, 1.8% had GTC seizures and another 1.8%, SE. Eighteen percent of patients had persistently normal R-EEG, 72.2% of them had discharges during VNPP. Generalized tonic-clonic seizures, myoclonic status epilepticus, and repeated seizures were the main risks of VNPP present in 6 (5.31%) patients while there were no complications during R-EEG. CONCLUSIONS: The VNPP in GGE is a useful tool in diagnosis and characterization of reflex traits, and is a safe procedure. Its use might preclude multiple R-EEG exams.

Gen SCN1A, Epilepsias Genéticas (Sindrome de DRAVET), Correlato Genotipo / Fenotipo / The SCN1A gene, congenital epilepsies (Dravet syndrome), genotype/phenotype correlations

Las mutaciones del Gen SCN1A están asociadas a varios síndromes epilépticos con presentaciones clínicas superpuestas y de variable severidad a saber: Epilepsia Severa Mioclonica de la Infancia o Síndrome de Dravet,Epilepsia Generalizada con Convulsiones Febriles Plus, formas más leves de Sindrome de Dravet, la Epilepsia Intratable con Convulsiones Generalizadas Tonico-Clonicas y raros casos de Migraña familiar. Todas estas formas clínicas representan el 90% de los casos de mutación del gen SCN1A; recientemente se han incluido la Epilepsia Focal y Generalizada Criptogenética, la Mioclónica–Astática, formas del Síndrome de Lennox-Gastaut y la forma severa de Epilepsia Multifocal Infantil (Epilepsia Migratoria o Multifocal Severa de la Infancia). El objetivo de la presentación de estos tres casos de Epilepsia Refractaria Precoz es enfatizar los Fenotipos variables en la evolución de la semiología convulsiva, y del compromiso cognitivo, asociado a genotipos variables (compromiso de alelos diferentes en el mismo Gen). Se debe sospechar compromiso del Gen SCN1A en toda Encefalopatía Epiléptica con convulsiones febriles de comienzo en el 1er año de vida repetidas, en muchas ocasiones, prolongadas o en ramilletes, refractarias al tratamiento médico, con neuroimagenes y EEG normales en el inicio del trastorno convulsivo aunque la regresión psicomotora ocurra años después o las mioclonias estén ausentes y en quienes la vulnerabilidad a la fiebre o a los estados infecciosos leves precipitan convulsiones

Mutations in the SCN1A gene are associated with different epi-lepsy syndromes with overlapping clinical presentations and of variable severity, such as severe myoclonic epilepsy in infancy or Dravet syndrome, generalized epilepsy with febrile seizures plus, milder forms of Dravet syndrome, refractory epilepsy with generalized tonic-clonic seizures, and rare cases of familial migraine. In 90% of all these clinical presentations SCN1A mutations are found. More recently, cryptogenic focal and ge-neralized epilepsy, myoclonic–astatic epilepsy, different types of Lennox-Gastaut syndrome, and the severe form of infantile multifocal epilepsy (migrating partial seizures or severe infanti-le multifocal epilepsy) have also been included. The aim of the presentation of these three cases of early refractory epilepsy was to emphasize the variable phenotypes in the evolution of seizure semiology and the cognitive involvement associated with variable genotypes (involvement of different alleles of the same gene). SCN1A-gene involvement should be suspected in the face of all epileptic encephalopathies...

Gen SCN1A, Epilepsias Genéticas (Sindrome de DRAVET), Correlato Genotipo / Fenotipo / The SCN1A gene, congenital epilepsies (Dravet syndrome), genotype/phenotype correlations

Las mutaciones del Gen SCN1A están asociadas a varios síndromes epilépticos con presentaciones clínicas superpuestas y de variable severidad a saber: Epilepsia Severa Mioclonica de la Infancia o Síndrome de Dravet,Epilepsia Generalizada con Convulsiones Febriles Plus, formas más leves de Sindrome de Dravet, la Epilepsia Intratable con Convulsiones Generalizadas Tonico-Clonicas y raros casos de Migraña familiar. Todas estas formas clínicas representan el 90% de los casos de mutación del gen SCN1A; recientemente se han incluido la Epilepsia Focal y Generalizada Criptogenética, la MioclónicaûAstática, formas del Síndrome de Lennox-Gastaut y la forma severa de Epilepsia Multifocal Infantil (Epilepsia Migratoria o Multifocal Severa de la Infancia). El objetivo de la presentación de estos tres casos de Epilepsia Refractaria Precoz es enfatizar los Fenotipos variables en la evolución de la semiología convulsiva, y del compromiso cognitivo, asociado a genotipos variables (compromiso de alelos diferentes en el mismo Gen). Se debe sospechar compromiso del Gen SCN1A en toda Encefalopatía Epiléptica con convulsiones febriles de comienzo en el 1er año de vida repetidas, en muchas ocasiones, prolongadas o en ramilletes, refractarias al tratamiento médico, con neuroimagenes y EEG normales en el inicio del trastorno convulsivo aunque la regresión psicomotora ocurra años después o las mioclonias estén ausentes y en quienes la vulnerabilidad a la fiebre o a los estados infecciosos leves precipitan convulsiones

[Simple febrile seizure, complex seizure, generalized epilepsy with febrile seizure plus, FIRES and new syndromes]. / Crisis febriles simples y complejas, epilepsia generalizada con crisis febriles plus, FIRES y nuevos síndromes.

Febrile seizures are the most common seizures in childhood. They have been observed in 2-5% of children before the age of 5, but in some populations this figure may increase to 15%. It is a common cause of pediatric hospital admissions and cause of anxiety for parents. Febrile seizures could be the first manifestation of epilepsy. About 13% of epileptic patients have a history of febrile seizure, and 30% have had recurrent febrile seizures. Their phenotypic characteristics allow, in the majority of cases, a classification of the seizure, an elaboration of a prognosis and to assume a specific therapeutic attitude. It is possible to describe a spectrum according to their severity, from the benign simple seizure to the more complex, febrile seizure plus, Dravet'syndrome, and FIRES. During the past decade, molecular genetic studies have contributed to the identification of genetic factors involved in febrile seizure and related disorders, making the necessity of a careful follow up of these patients in order to detect risk factors earlier. We have reviewed the medical literature to update current knowledge of febrile seizures, their prognosis and their relation to new epileptic syndromes.

Segregation of a haplotype encompassing FEB1 with genetic epilepsy with febrile seizures plus in a Colombian family.

Febrile seizures and epilepsy are believed to be linked and some forms of epilepsy are associated with a history of febrile seizures (FS). Linkage analysis to seven known loci for FS and/or genetic epilepsy with febrile seizures plus (GEFS plus) was performed in a small Colombian family. Short tandem repeat (STR) markers were genotyped and two-point linkage analysis and haplotype reconstruction were conducted. A maximum LOD score of 0.75 at marker D8S533 for FEB1 at a recombination fraction (θ) of 0 and a segregating haplotype were identified. FEB1 was the first locus to be associated with FS and this is the second report to describe this association. Two genes in this region, CRH and DEPDC2, are good putative candidate genes that may play a role in FS and/or GEFS plus.

Crisis febriles simples y complejas, epilepsia generalizada con crisis febriles plus, FIRES y nuevos síndromes. / [Simple febrile seizure, complex seizure, generalized epilepsy with febrile seizure plus, FIRES and new syndromes].

Febrile seizures are the most common seizures in childhood. They have been observed in 2-5

of children before the age of 5, but in some populations this figure may increase to 15

. It is a common cause of pediatric hospital admissions and cause of anxiety for parents. Febrile seizures could be the first manifestation of epilepsy. About 13

of epileptic patients have a history of febrile seizure, and 30

have had recurrent febrile seizures. Their phenotypic characteristics allow, in the majority of cases, a classification of the seizure, an elaboration of a prognosis and to assume a specific therapeutic attitude. It is possible to describe a spectrum according to their severity, from the benign simple seizure to the more complex, febrile seizure plus, Dravetsyndrome, and FIRES. During the past decade, molecular genetic studies have contributed to the identification of genetic factors involved in febrile seizure and related disorders, making the necessity of a careful follow up of these patients in order to detect risk factors earlier. We have reviewed the medical literature to update current knowledge of febrile seizures, their prognosis and their relation to new epileptic syndromes.

Crisis febriles simples y complejas, epilepsia generalizada con crisis febriles plus, FIRES y nuevos síndromes / [Simple febrile seizure, complex seizure, generalized epilepsy with febrile seizure plus, FIRES and new syndromes].

Febrile seizures are the most common seizures in childhood. They have been observed in 2-5

of children before the age of 5, but in some populations this figure may increase to 15

. It is a common cause of pediatric hospital admissions and cause of anxiety for parents. Febrile seizures could be the first manifestation of epilepsy. About 13

of epileptic patients have a history of febrile seizure, and 30

have had recurrent febrile seizures. Their phenotypic characteristics allow, in the majority of cases, a classification of the seizure, an elaboration of a prognosis and to assume a specific therapeutic attitude. It is possible to describe a spectrum according to their severity, from the benign simple seizure to the more complex, febrile seizure plus, Dravet’syndrome, and FIRES. During the past decade, molecular genetic studies have contributed to the identification of genetic factors involved in febrile seizure and related disorders, making the necessity of a careful follow up of these patients in order to detect risk factors earlier. We have reviewed the medical literature to update current knowledge of febrile seizures, their prognosis and their relation to new epileptic syndromes.

Screening of GABRB3 in French-Canadian families with idiopathic generalized epilepsy.

Mutations in the GABRB3 have been recently associated with childhood absence epilepsy (CAE) in families from Honduras and Mexico. In this study, we aimed to determine the frequency of mutation in this gene in our cohort of families with CAE and other related idiopathic generalized epilepsy (IGE) syndromes. We screened the open reading frame of GABRB3 in 183 French-Canadian individuals with IGE, including 88 with CAE. A total of nine single nucleotide polymorphisms (SNPs) have been identified,five of which are novel. The previously described P11S missense mutation was found in three affected and one unaffected individuals from a French-Canadian family. However, the P11S variant was also found in one of our 190 control individuals of French-Canadian origin, suggesting that this variant is rather a rare polymorphism in this population. Further screening of other IGE cohorts from various ethnic origins would help to confirm the association between this rare functional variant and epilepsy.

The genetics of epilepsies.

OBJECTIVES: To discuss some of the clinical and molecular genetic aspects of new discoveries in the field of the genetics of the epilepsies and relate these with relevant clues for a better understanding of the mechanisms underlying some of the monogenic epilepsy syndromes. SOURCES: Many study designs have been performed over the years and these include family-based studies, genetic-epidemiology surveys. More recently, molecular genetics studies and gene discovery strategies have been used to unravel the molecular and cell mechanisms involved in several Mendelian epilepsy syndromes. SUMMARY OF THE FINDINGS: The importance of genetic factors in the epilepsies has been recognized since the time of Hippocrates. CONCLUSIONS: In the modern era, many studies have demonstrated the existence of an inherited component in the generalized and focal epilepsies and in the last 2 decades a number of families segregating different types of monogenic epilepsy have been described, leading to progresses in the characterization of the molecular defects in these families.

A genética das epilepsias: [revisão] / The genetics of epilepsies: [review]

OBJETIVO: Discutir alguns dos aspectos genéticos clínicos e moleculares de novas descobertas no campo da genética das epilepsias e relacioná-las com indicações importantes para a melhor compreensão dos mecanismos subjacentes a algumas síndromes epilépticas monogênicas. FONTES DOS DADOS: Muitos desenhos de estudo foram usados através dos anos, incluindo estudos familiares e pesquisas genético-epidemiológicas. Mais recentemente, estudos de genética molecular e estratégias de descoberta de genes foram usados para revelar os mecanismos moleculares e celulares envolvidas em diversas síndromes epilépticas mendelianas. SÍNTESE DOS DADOS: A importância dos fatores genéticos em epilepsias é reconhecida desde os tempos de Hipócrates. CONCLUSÕES: Nos tempos modernos, muitos estudos demonstraram a existência de um componente hereditário nas epilepsias generalizadas e focais. Nas últimas duas décadas, diversas famílias segregando diferentes tipos de epilepsia monogência foram descritas, o que levou ao progresso na caracterização dos defeitos moleculares nestas famílias.

OBJECTIVES: To discuss some of the clinical and molecular genetic aspects of new discoveries in the field of the genetics of the epilepsies and relate these with relevant clues for a better understanding of the mechanisms underlying some of the monogenic epilepsy syndromes. SOURCES: Many study designs have been performed over the years and these include family-based studies, genetic-epidemiology surveys. More recently, molecular genetics studies and gene discovery strategies have been used to unravel the molecular and cell mechanisms involved in several Mendelian epilepsy syndromes. SUMMARY OF THE FINDINGS: The importance of genetic factors in the epilepsies has been recognized since the time of Hippocrates. CONCLUSIONS: In the modern era, many studies have demonstrated the existence of an inherited component in the generalized and focal epilepsies and in the last 2 decades a number of families segregating different types of monogenic epilepsy have been described, leading to progresses in the characterization of the molecular defects in these families.

Dravet syndrome: a study of 53 patients.

OBJECTIVE: We analyzed the electroclinical features, treatment and evolution of patients with Dravet syndrome (DS). MATERIAL AND METHODS: We evaluated the clinical records of 53 patients that met the diagnostic criteria of DS according to the ILAE classification of 1989 seen at our center between February 1990 and December 2004. RESULTS: Thirty-four male and 19 female patients met the diagnostic criteria of DS. Mean time of follow-up was 10 years. The mean age at onset was 6 months and in all patients the seizures were associated with febrile illness. Myoclonias were found in 39 children. These seizures appeared between the ages of 1 and 5.5 years, with an average of 1 year and 5 months. The seizures were difficult to control with AEDs. All patients presented some degree of mental delay. At the age of 6 years, one of the children in our series presented kinesigenic paroxysmal dyskinesias. Twenty patients were placed on the ketogenic diet (KD). Two did not tolerate the KD and the diet was ineffective in five cases. The other 13 showed different degrees of control of seizures. CONCLUSION: The present study confirms the severity and intractability of the seizures and the difficulties to make an early diagnosis in DS. The onset of febrile seizures or seizures related to infectious disease or vaccination, focal or generalized, prolonged in time and during the first year of life, is especially suggestive of DS. The final diagnosis is usually made after 2 or 3 years when the electroclinical picture is complete, but earlier diagnosis is desirable. Myoclonias are the most representative type of non-febrile seizures in this syndrome but are not always present. Cognitive development is poor in all patients. Treatment with the KD should be considered early. A ion-channel disorder could explain the association between DS and paroxysmal diskinesias, as seen in one of our patients.

Central nervous system hyperexcitability associated with glutamate dehydrogenase gain of function mutations.

OBJECTIVE: To describe seizure phenotypes associated with the hyperinsulinism/hyperammonemia syndrome (HI/HA), which is caused by gain of function mutations in the enzyme glutamate dehydrogenase (GDH). STUDY DESIGN: A retrospective review of records of 14 patients with HI/HA. RESULTS: Nine patients had seizures as the first symptom of HI/HA, and six had seizures in the absence of hypoglycemia. No electroencephalogram (EEG) background abnormalities were identified. In four patients, EEG recordings during seizures in the setting of normal blood glucose contained generalized epileptiform discharges. EEGs of three of these patients showed 0.5- to 2-second generalized irregular spike-and-wave discharge at 3 to 6 Hz corresponding to eye blinks, eye rolling, or staring. The EEG of the fourth patient consisted of 20 seconds of generalized regular spike-and-wave discharge at 3 Hz in the clinical context of staring and unresponsiveness. In two patients, seizure control worsened with carbamezapine or oxcarbezapine treatment. CONCLUSIONS: In patients with HI/HA, generalized seizures are common and can occur in the absence of hypoglycemia. The drugs carbamazepine and oxcarbazepine should be used with caution for treatment. Pathogenesis of epilepsy in these patients may be related to effects of GDH mutations in the brain, perhaps in combination with effects of recurrent hypoglycemia and chronic hyperammonemia.