Clustered de novo start-loss variants in GLUL result in a developmental and epileptic encephalopathy via stabilization of glutamine synthetase.

Glutamine synthetase (GS), encoded by GLUL, catalyzes the conversion of glutamate to glutamine. GS is pivotal for the generation of the neurotransmitters glutamate and gamma-aminobutyric acid and is the primary mechanism of ammonia detoxification in the brain. GS levels are regulated post-translationally by an N-terminal degron that enables the ubiquitin-mediated degradation of GS in a glutamine-induced manner. GS deficiency in humans is known to lead to neurological defects and death in infancy, yet how dysregulation of the degron-mediated control of GS levels might affect neurodevelopment is unknown. We ascertained nine individuals with severe developmental delay, seizures, and white matter abnormalities but normal plasma and cerebrospinal fluid biochemistry with de novo variants in GLUL. Seven out of nine were start-loss variants and two out of nine disrupted 5' UTR splicing resulting in splice exclusion of the initiation codon. Using transfection-based expression systems and mass spectrometry, these variants were shown to lead to translation initiation of GS from methionine 18, downstream of the N-terminal degron motif, resulting in a protein that is stable and enzymatically competent but insensitive to negative feedback by glutamine. Analysis of human single-cell transcriptomes demonstrated that GLUL is widely expressed in neuro- and glial-progenitor cells and mature astrocytes but not in post-mitotic neurons. One individual with a start-loss GLUL variant demonstrated periventricular nodular heterotopia, a neuronal migration disorder, yet overexpression of stabilized GS in mice using in utero electroporation demonstrated no migratory deficits. These findings underline the importance of tight regulation of glutamine metabolism during neurodevelopment in humans.

Ethosuximide lowers lamotrigine serum concentrations: Evidence for a clinically relevant interaction.

We investigated the effect of comedication with ethosuximide (ESM) on lamotrigine (LTG) blood levels. Based on observations from clinical practice, we hypothesized that ESM reduces the LTG serum concentration. We additionally evaluated this effect in the presence of concomitant valproic acid (VPA). We retrospectively analyzed samples of inpatients from our department who had been treated with a combination of ESM and LTG between 2017 and 2021. We additionally used data on LTG serum concentrations from a previously published cohort from our center. Generalized estimation equations (GEEs) were used for statistical analyses. We included 523 samples from 209 patients. GEE analyses showed that LTG trough serum concentrations were significantly lower in samples with ESM comedication and significantly higher in samples with concomitant VPA. The effect of ESM was moderated by patients' age; in children and adolescents, LTG serum concentrations were 37% lower than in samples without ESM, whereas in adults, LTG serum concentrations were 14% lower. The effect we found in our data is relevant to daily clinical practice, if patients are not seizure-free despite typical daily LTG dosage, or if they develop side effects during ESM withdrawal. It should be considered especially in children and adolescents.

Heterozygous loss-of-function variants in DOCK4 cause neurodevelopmental delay and microcephaly.

Neurons form the basic anatomical and functional structure of the nervous system, and defects in neuronal differentiation or formation of neurites are associated with various psychiatric and neurodevelopmental disorders. Dynamic changes in the cytoskeleton are essential for this process, which is, inter alia, controlled by the dedicator of cytokinesis 4 (DOCK4) through the activation of RAC1. Here, we clinically describe 7 individuals (6 males and one female) with variants in DOCK4 and overlapping phenotype of mild to severe global developmental delay. Additional symptoms include coordination or gait abnormalities, microcephaly, nonspecific brain malformations, hypotonia and seizures. Four individuals carry missense variants (three of them detected de novo) and three individuals carry null variants (two of them maternally inherited). Molecular modeling of the heterozygous missense variants suggests that the majority of them affect the globular structure of DOCK4. In vitro functional expression studies in transfected Neuro-2A cells showed that all missense variants impaired neurite outgrowth. Furthermore, Dock4 knockout Neuro-2A cells also exhibited defects in promoting neurite outgrowth. Our results, including clinical, molecular and functional data, suggest that loss-of-function variants in DOCK4 probable cause a variable spectrum of a novel neurodevelopmental disorder with microcephaly.

Critical incidents, nocturnal supervision, and caregiver knowledge on SUDEP in patients with Dravet syndrome: A prospective multicenter study in Germany.

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

GABRA1-Related Disorders: From Genetic to Functional Pathways.

OBJECTIVE: Variants in GABRA1 have been associated with a broad epilepsy spectrum, ranging from genetic generalized epilepsies to developmental and epileptic encephalopathies. However, our understanding of what determines the phenotype severity and best treatment options remains inadequate. We therefore aimed to analyze the electroclinical features and the functional effects of GABRA1 variants to establish genotype-phenotype correlations. METHODS: Genetic and electroclinical data of 27 individuals (22 unrelated and 2 families) harboring 20 different GABRA1 variants were collected and accompanied by functional analysis of 19 variants. RESULTS: Individuals in this cohort could be assigned into different clinical subgroups based on the functional effect of their variant and its structural position within the GABRA1 subunit. A homogenous phenotype with mild cognitive impairment and infantile onset epilepsy (focal seizures, fever sensitivity, and electroencephalographic posterior epileptiform discharges) was described for variants in the extracellular domain and the small transmembrane loops. These variants displayed loss-of-function (LoF) effects, and the patients generally had a favorable outcome. A more severe phenotype was associated with variants in the pore-forming transmembrane helices. These variants displayed either gain-of-function (GoF) or LoF effects. GoF variants were associated with severe early onset neurodevelopmental disorders, including early infantile developmental and epileptic encephalopathy. INTERPRETATION: Our data expand the genetic and phenotypic spectrum of GABRA1 epilepsies and permit delineation of specific subphenotypes for LoF and GoF variants, through the heterogeneity of phenotypes and variants. Generally, variants in the transmembrane helices cause more severe phenotypes, in particular GoF variants. These findings establish the basis for a better understanding of the pathomechanism and a precision medicine approach in GABRA1-related disorders. Further studies in larger populations are needed to provide a conclusive genotype-phenotype correlation. ANN NEUROL 2023.

Fenfluramine in the treatment of Dravet syndrome: Results of a third randomized, placebo-controlled clinical trial.

OBJECTIVE: This study was undertaken to assess the safety and efficacy of fenfluramine in the treatment of convulsive seizures in patients with Dravet syndrome. METHODS: This multicenter, randomized, double-blind, placebo-controlled, parallel-group, phase 3 clinical trial enrolled patients with Dravet syndrome, aged 2-18 years with poorly controlled convulsive seizures, provided they were not also receiving stiripentol. Eligible patients who had ≥6 convulsive seizures during the 6-week baseline period were randomized to placebo, fenfluramine .2 mg/kg/day, or fenfluramine .7 mg/kg/day (1:1:1 ratio) administered orally (maximum dose = 26 mg/day). Doses were titrated over 2 weeks and maintained for an additional 12 weeks. The primary endpoint was a comparison of the monthly convulsive seizure frequency (MCSF) during baseline and during the combined titration-maintenance period in patients given fenfluramine .7 mg/kg/day versus patients given placebo. RESULTS: A total of 169 patients were screened, and 143 were randomized to treatment. Mean age was 9.3 ± 4.7 years (±SD), 51% were male, and median baseline MCSF in the three groups ranged 12.7-18.0 per 28 days. Patients treated with fenfluramine .7 mg/kg/day demonstrated a 64.8% (95% confidence interval = 51.8%-74.2%) greater reduction in MCSF compared with placebo (p < .0001). Following fenfluramine .7 mg/kg/day, 72.9% of patients had a ≥50% reduction in MCSF compared with 6.3% in the placebo group (p < .0001). The median longest seizure-free interval was 30 days in the fenfluramine .7 mg/kg/day group compared with 10 days in the placebo group (p < .0001). The most common adverse events (>15% in any group) were decreased appetite, somnolence, pyrexia, and decreased blood glucose. All occurred in higher frequency in fenfluramine groups than placebo. No evidence of valvular heart disease or pulmonary artery hypertension was detected. SIGNIFICANCE: The results of this third phase 3 clinical trial provide further evidence of the magnitude and durability of the antiseizure response of fenfluramine in children with Dravet syndrome.

Hemispherotomy in children: A retrospective analysis of 152 surgeries at a single center and predictors for long-term seizure outcome.

OBJECTIVE: Completeness as a predictor of seizure freedom is broadly accepted in epilepsy surgery. We focused on the requirements for a complete hemispherotomy and hypothesized that the disconnection of the insula contributes to a favorable postoperative seizure outcome. We analyzed surgical and nonsurgical predictors influencing long-term seizure outcome before and after a modification of our hemispherotomy technique. METHODS: We retrospectively studied surgical procedures, electroclinical parameters, magnetic resonance imaging (MRI) results, and follow-up data in all children who had undergone hemispherotomy between 2001 and 2018 at our institution. We used logistic regression models to analyze the influence of different factors on seizure outcome. RESULTS: A total of 152 patients were eligible for seizure outcome analysis only. Of these, 140 cases had complete follow-up data for ≥24 months and provide the basis for the following results. The median age at surgery was 4.3 years (range = .3-17.9 years). Complete disconnection (including the insular tissue) was achieved in 63.6% (89/140). At 2-year follow-up, seizure freedom (Engel class IA) was observed in 34.8% (8/23) with incomplete insular disconnection, whereas this was achieved in 88.8% (79/89) with complete surgical disconnection (p < .001, odds ratio [OR] = 10.41). In the latter group (n = 89), a potentially epileptogenic contralateral MRI lesion was the strongest predictor for postoperative seizure recurrence (OR = 22.20). SIGNIFICANCE: Complete surgical disconnection is the most important predictor of seizure freedom following hemispherotomy and requires disconnection of the insular tissue at the basal ganglia level. Even if the hemispherotomy is performed surgically completely, a potentially epileptogenic contralateral lesion on preoperative MRI significantly reduces the chances of postoperative seizure freedom.

Sleep quality, anxiety, symptoms of depression, and caregiver burden among those caring for patients with Dravet syndrome: a prospective multicenter study in Germany.

BACKGROUND: This study measured sleep quality among caregivers of patients with Dravet syndrome (DS) and assessed the impacts of mental health problems and caregiver burden on sleep quality. METHODS: This multicenter, cross-sectional study of patients with DS and their caregivers throughout Germany consisted of a questionnaire and a prospective 4-week diary querying disease characteristics, demographic data, living conditions, nocturnal supervision, and caregivers' work situations. Sleep quality was assessed using the Pittsburgh Sleeping Quality Index (PSQI). The Hospital Anxiety and Depression Scale (HADS) and the Burden Scale for Family Caregivers (BSFC) were used to measure anxiety, symptoms of depression, and caregiver burden. RESULTS: Our analysis included 108 questionnaires and 82 four-week diaries. Patients with DS were 49.1% male (n = 53), with a mean age of 13.5 ± 10.0 years. Caregivers were 92.6% (n = 100) female, with a mean age of 44.7 ± 10.6 years. The overall mean PSQI score was 8.7 ± 3.5, with 76.9% of participants (n = 83) scoring 6 or higher, indicating abnormal sleep quality. The HADS for anxiety and depression had overall mean scores of 9.3 ± 4.3 and 7.9 ± 3.7, respectively; 61.8% and 50.9% of participants scored above the cutoff value of 8 for anxiety and depression, respectively. Statistical analyses revealed caregiver anxiety levels and patients' sleep disturbances as major factors influencing PSQI scores. The overall mean BSFC score of 41.7 ± 11.7 indicates a moderate burden, with 45.3% of caregivers scoring 42 or higher. CONCLUSIONS: Sleep quality is severely affected among caregivers of patients with DS, correlating with anxiety, comorbidities, and patients' sleep disturbances. A holistic therapeutic approach should be implemented for patients with DS and their caregivers, focusing on the sleep quality and mental health of caregivers. TRIAL REGISTRATION: German Clinical Trials Register (DRKS), DRKS00016967. Registered 27 May 2019, http://www.drks.de/DRKS00016967.

Biophysical characterization and modelling of SCN1A gain-of-function predicts interneuron hyperexcitability and a predisposition to network instability through homeostatic plasticity.

SCN1A gain-of-function variants are associated with early onset developmental and epileptic encephalopathies (DEEs) that possess distinct clinical features compared to Dravet syndrome caused by SCN1A loss-of-function. However, it is unclear how SCN1A gain-of-function may predispose to cortical hyper-excitability and seizures. Here, we first report the clinical features of a patient carrying a de novo SCN1A variant (T162I) associated with neonatal-onset DEE, and then characterize the biophysical properties of T162I and three other SCN1A variants associated with neonatal-onset DEE (I236V) and early infantile DEE (P1345S, R1636Q). In voltage clamp experiments, three variants (T162I, P1345S and R1636Q) exhibited changes in activation and inactivation properties that enhanced window current, consistent with gain-of-function. Dynamic action potential clamp experiments utilising model neurons incorporating Nav1.1. channels supported a gain-of-function mechanism for all four variants. Here, the T162I, I236V, P1345S, and R1636Q variants exhibited higher peak firing rates relative to wild type and the T162I and R1636Q variants produced a hyperpolarized threshold and reduced neuronal rheobase. To explore the impact of these variants upon cortical excitability, we used a spiking network model containing an excitatory pyramidal cell (PC) and parvalbumin positive (PV) interneuron population. SCN1A gain-of-function was modelled by enhancing the excitability of PV interneurons and then incorporating three simple forms of homeostatic plasticity that restored pyramidal cell firing rates. We found that homeostatic plasticity mechanisms exerted differential impact upon network function, with changes to PV-to-PC and PC-to-PC synaptic strength predisposing to network instability. Overall, our findings support a role for SCN1A gain-of-function and inhibitory interneuron hyperexcitability in early onset DEE. We propose a mechanism through which homeostatic plasticity pathways can predispose to pathological excitatory activity and contribute to phenotypic variability in SCN1A disorders.

Clinical Features, Neuropathology, and Surgical Outcome in Patients With Refractory Epilepsy and Brain Somatic Variants in the SLC35A2 Gene.

BACKGROUND AND OBJECTIVES: The SLC35A2 gene, located at chromosome Xp11.23, encodes for a uridine diphosphate-galactose transporter. We describe clinical, genetic, neuroimaging, EEG, and histopathologic findings and assess possible predictors of postoperative seizure and cognitive outcome in 47 patients with refractory epilepsy and brain somatic SLC35A2 gene variants. METHODS: This is a retrospective multicenter study where we performed a descriptive analysis and classical hypothesis testing. We included the variables of interest significantly associated with the outcomes in the generalized linear models. RESULTS: Two main phenotypes were associated with brain somatic SLC35A2 variants: (1) early epileptic encephalopathy (EE, 39 patients) with epileptic spasms as the predominant seizure type and moderate to severe intellectual disability and (2) drug-resistant focal epilepsy (DR-FE, 8 patients) associated with normal/borderline cognitive function and specific neuropsychological deficits. Brain MRI was abnormal in all patients with EE and in 50% of those with DR-FE. Histopathology review identified mild malformation of cortical development with oligodendroglial hyperplasia in epilepsy in 44/47 patients and was inconclusive in 3. The 47 patients harbored 42 distinct mosaic SLC35A2 variants, including 14 (33.3%) missense, 13 (30.9%) frameshift, 10 (23.8%) nonsense, 4 (9.5%) in-frame deletions/duplications, and 1 (2.4%) splicing variant. Variant allele frequencies (VAFs) ranged from 1.4% to 52.6% (mean VAF: 17.3 ± 13.5). At last follow-up (35.5 ± 21.5 months), 30 patients (63.8%) were in Engel Class I, of which 26 (55.3%) were in Class IA. Cognitive performances remained unchanged in most patients after surgery. Regression analyses showed that the probability of achieving both Engel Class IA and Class I outcomes, adjusted by age at seizure onset, was lower when the duration of epilepsy increased and higher when postoperative EEG was normal or improved. Lower brain VAF was associated with improved postoperative cognitive outcome in the analysis of associations, but this finding was not confirmed in regression analyses. DISCUSSION: Brain somatic SLC35A2 gene variants are associated with 2 main clinical phenotypes, EE and DR-FE, and a histopathologic diagnosis of MOGHE. Additional studies will be needed to delineate any possible correlation between specific genetic variants, mutational load in the epileptogenic tissue, and surgical outcomes.

An examination of the efficacy and safety of fenfluramine in adults, children, and adolescents with Dravet syndrome in a real-world practice setting: A report from the Fenfluramine European Early Access Program.

OBJECTIVE: To examine the efficacy and safety of fenfluramine in patients with Dravet syndrome (DS) in three age groups: <6, 6-17, and ≥18 years old, treated in a real-world setting. METHODS: Patients with DS were treated with fenfluramine in the European Union Early Access Program (EAP). Following a 28-day baseline period to establish the pretreatment monthly convulsive seizure frequency (MCSF), fenfluramine was started at a dose chosen by the treating physician and gradually titrated based on efficacy and tolerability up to a maximum of 0.7 mg/kg/day. Seizure incidence was recorded in a written diary, and adverse events (AEs) were reported at each patient visit. Cardiovascular safety was assessed by transthoracic echocardiography before treatment started and at least every 6 months thereafter. RESULTS: A total of 149 patients have enrolled in the EAP and 63 were <6 years old, 62 were 6-17 years old, and 24 were ≥18 years old. After 3 months of treatment 62%, 53%, and 50% of patients demonstrated ≥75% reduction in MCSF in the <6, 6-17, and ≥18-year-old groups, respectively. This pattern of response was sustained through 12 months of treatment with 55%, 46%, and 80% of the <6, 6-17, and ≥18-year-old groups, respectively, experiencing a ≥75% reduction in MCSF. Most common AEs were loss of appetite (21%) and somnolence (16%). No valvular heart disease or pulmonary artery hypertension was observed. SIGNIFICANCE: The magnitude, consistency, and durability of the response to add-on fenfluramine is consistent across age groups in patients with Dravet syndrome.

Exploring the relationships between composite scores of disease severity, seizure-freedom and quality of life in Dravet syndrome.

BACKGROUND: In Dravet syndrome (DS), a rare epileptic and developmental encephalopathy, the effectiveness of a new treatment is predominantly measured in terms of seizure frequency. However, this may not fully capture the impact of a treatment on the broader aspects of the syndrome and patients' health-related quality of life (HRQoL). Using a previously published survey which collected data from DS patients and their carers on the broader manifestations of their syndrome, their HRQoL, and their experience of seizures, this study created composite measures of symptom severity to offer new perspectives on the multifaceted aspects of this rare condition. METHODS: Survey responses on the severity of physical and psychosocial symptoms were combined with independent assessments of disability and care need, to generate three composite symptom scores assessing the manifestations of DS (physical, psychosocial and care requirements). Variation in HRQoL was investigated in multiple regression analyses to assess the strength of association between each of these composite measures and three forms of seizure measures (seizure frequency, days with no seizures and longest interval without seizures), as experienced over a 4- and 12-week period. RESULTS: Composite scores were calculated for a cohort of 75 primarily paediatric patients who were enrolled in the study. Strong associations were found between each of the three composite symptom scores and each of the three seizure measures, with the regression coefficient on symptom score highly significant (p ≤ 0.001) in all nine comparisons. Separate regressions using predictors of HRQoL (Kiddy KINDL and Kid KINDL) as the dependent variable were inconclusive, identifying only behavioural/attention problems and status epilepticus as significant predictors of HRQoL. CONCLUSIONS: These results allow the development of a composite score that may be useful in developing a clinical understanding of the severity of DS for an individual patient and establishing their treatment goals. Where measurement of long-term sequalae of disease is not feasible, such as clinical trials, correlation of the composite score with experience of seizures and seizure-free periods may allow a better contextualisation of the results of short-term assessments. TRIAL REGISTRATION: German Clinical Trials Register (DRKS), DRKS00011894. Registered 16 March 2017, http://www.drks.de/ DRKS00011894.

DNA methylation-based classification of malformations of cortical development in the human brain.

Malformations of cortical development (MCD) comprise a broad spectrum of structural brain lesions frequently associated with epilepsy. Disease definition and diagnosis remain challenging and are often prone to arbitrary judgment. Molecular classification of histopathological entities may help rationalize the diagnostic process. We present a retrospective, multi-center analysis of genome-wide DNA methylation from human brain specimens obtained from epilepsy surgery using EPIC 850 K BeadChip arrays. A total of 308 samples were included in the study. In the reference cohort, 239 formalin-fixed and paraffin-embedded (FFPE) tissue samples were histopathologically classified as MCD, including 12 major subtype pathologies. They were compared to 15 FFPE samples from surgical non-MCD cortices and 11 FFPE samples from post-mortem non-epilepsy controls. We applied three different statistical approaches to decipher the DNA methylation pattern of histopathological MCD entities, i.e., pairwise comparison, machine learning, and deep learning algorithms. Our deep learning model, which represented a shallow neuronal network, achieved the highest level of accuracy. A test cohort of 43 independent surgical samples from different epilepsy centers was used to test the precision of our DNA methylation-based MCD classifier. All samples from the test cohort were accurately assigned to their disease classes by the algorithm. These data demonstrate DNA methylation-based MCD classification suitability across major histopathological entities amenable to epilepsy surgery and age groups and will help establish an integrated diagnostic classification scheme for epilepsy-associated MCD.

Development and Validation of Prediction Models for Developmental and Intellectual Outcome Following Pediatric Epilepsy Surgery.

BACKGROUND AND OBJECTIVES: To identify predictors of postoperative intelligence and developmental quotients (IQ/DQ) and develop and validate clinically applicable IQ/DQ prediction models. METHODS: We retrospectively analyzed neuropsychological outcomes and their possible determinants for children treated in Bethel and Utrecht since 1990. We performed separate analyses for patients with IQ and those with only DQ available. We developed prediction models based on presurgical determinants to predict dichotomized levels of performance (IQ ≥85, IQ ≥70, DQ ≥50). RESULTS: IQ/DQ data before and 2 years after surgery were available for 492 patients (IQ n = 365, DQ n = 127). At a cutoff level ±10 points, the chance of improvement was considerably higher than the chance of deterioration (IQ 37.3% vs 6.6% and DQ 31.5% vs 15.0%, respectively). Presurgical IQ/DQ was the strongest predictor of postoperative cognition (IQ r = 0.85, p <0.001; DQ r = 0.57, p <0.001). Two IQ models were developed in the Bethel cohort (n = 258) and externally validated in the Utrecht cohort (n = 102). For DQ, we developed the model in the Bethel cohort and used 10-fold cross-validation. Models allowed good prediction at all 3 cutoff levels (correct classification for IQ ≥85 = 86%, IQ ≥70 = 91%, DQ ≥50 = 76%). External validation of the IQ models showed high accuracy (IQ ≥85: 0.82, confidence interval [CI] 0.75-0.91; IQ ≥70: 0.84, CI 0.77-0.92) and excellent discrimination (receiver operating characteristic curves: IQ ≥85: area under the curve [AUC] 0.90, CI 0.84-0.96; IQ ≥70: AUC 0.92, CI 0.87-0.97). DISCUSSION: After epilepsy surgery in children, the risk of cognitive deterioration is very low. Presurgical development has a strong effect on the postoperative trajectory. The presented models can improve presurgical counseling of patients and parents by reliably predicting cognitive outcomes. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that for children undergoing epilepsy surgery presurgical IQ/DQ was the strongest predictor of postoperative cognition.

Hypochondroplasia and temporal lobe epilepsy - A series of 4 cases.

Hypochondroplasia is a skeletal dysplasia syndrome with an autosomal dominant inheritance. It may be associated with temporal lobe epilepsy. We present a series of four patients (two female, two male) with hypochondroplasia who presented at our center with drug refractory epilepsy. Clinical details and EEG and MRI findings led to a diagnosis of temporal lobe epilepsy in all four cases. The MRI findings indicate the epilepsy in hypochondroplasia may be associated with bilateral temporal lobe dysgenesis.

Adjunctive everolimus therapy for tuberous sclerosis complex-associated refractory seizures: Results from the postextension phase of EXIST-3.

OBJECTIVE: Epilepsy is highly prevalent in patients with tuberous sclerosis complex (TSC). Everolimus showed higher efficacy than placebo for seizures in the primary analysis of the EXIST-3 study. Here, we present the long-term outcomes of everolimus at the end of the postextension phase (PEP; data cutoff date: October 25, 2017). METHODS: After completion of the extension phase, patients were invited to continue everolimus in the PEP with everolimus (targeted trough concentration = 5-15 ng/ml, investigator-judged). Efficacy assessments included changes in seizure status during the PEP collected at 12-week intervals as parent/caregiver-reported data through a structured questionnaire. RESULTS: Among 361 patients, 343 entered the extension phase and 249 entered the PEP. After 12 weeks in the PEP, 18.9% (46/244) of patients were seizure-free since the last visit of the extension phase and 64.8% (158/244) had a stable/improved seizure status. At 24 weeks, the corresponding percentages were 18.2% (42/231) and 64.5% (149/231). Among 244 patients, the response rate was 32.8% (80/244) during the 12-week maintenance period of the core phase and 63.9% (156/244) at the end of the extension phase. Of the 149 responders at the end of the extension phase, 70.5% were seizure-free or had stable/improved seizure status. Long-term efficacy data showed persistent responses were observed in 183 of 361 patients (50.7%); 63.9% of these patients had a response that lasted at least 48 weeks. The most frequent Grade 3-4 adverse events (≥2% incidence) reported throughout the study were pneumonia, status epilepticus, seizure, stomatitis, neutropenia, and gastroenteritis. Four patients died during the study. SIGNIFICANCE: The final analysis of EXIST-3 demonstrated the sustained efficacy of everolimus as adjunctive therapy in patients with TSC-associated treatment-refractory seizures, with a tolerable safety profile.

Reading and the visual word form area (VWFA) - Management and clinical experience at one epilepsy surgery center.

OBJECTIVE: Presurgical evaluation has no established routine to assess reading competence and to identify essential "not to resect" reading areas. Functional models describe a visual word form area (VWFA) located in the midfusiform gyrus in the dominant ventral occipito-temporal cortex (vOTC) as essential for reading. We demonstrate the relevance and feasibility of invasive VWFA-mapping. METHODS: Four patients with epilepsy received invasive VWFA-mapping via left temporo-basal strip-electrodes. Co-registration of the results and additional data from the literature led to the definition of a region of interest (ROI) for a retrospective assessment of postoperative reading deficits by a standardized telephone-interview in patients with resections in this ROI between 2004 and 2018. RESULTS: Electrical cortical stimulation disturbed whole word recognition and reading in four patients with structural epilepsy. Stimulation results showed distribution in the basal temporal lobe (dorsal mesencephalon to preoccipital notch). We identified 34 patients with resections in the ROI of the dominant hemisphere. Of these, 15 (44.1%) showed a postoperative reading deficit with a mean duration of 18.2 months (+/-32.4, 0.5-122). Six patients suffered from letter-by-letter (LBL) reading. Two patients had permanent LBL reading after resection in the ROI. SIGNIFICANCE: We present evidence on the functional relevance of the vOTC for reading by (1) extra-operative cortical stimulation of the VWFA and by (2) a retrospective case study of reading deficits in patients operated in this area. Reading assessments and data concerning essential reading structures should be included in the presurgical evaluation of patients with lesions in the left vOTC.

Treatment with fenfluramine in patients with Dravet syndrome has no long-term effects on weight and growth.

OBJECTIVE: Appetite disturbance and growth abnormalities are commonly reported in children with Dravet syndrome (DS). Fenfluramine (Fintepla) has demonstrated profound reduction in convulsive seizure frequency in DS and was recently approved for use in DS in the US and EU. Prior to its use in epilepsy, fenfluramine was approved to suppress appetite in obese adults. Here, we evaluated the impact of fenfluramine on weight and growth in patients with DS treated for ≥12 months or ≥24 months and compared the results with growth curves in normative reference populations and published historical controls among patients with DS. METHODS: Historical control data from a recent study of 68 patients with DS show decreases in height and weight Z-scores of ∼0.1 standard deviation (SD) for every 12-month increase in age (Eschbach K. Seizure. 2017;52:117-22). Anthropometric data for fenfluramine were extracted from an open-label extension (OLE) study of eligible patients with DS (2-18 y/o; fenfluramine dose: 0.2-0.7 mg/kg/day). Z-score analyses were based on the Boston Children's Hospital algorithm and assessed potential impact of fenfluramine on growth at OLE baseline, at Month 12, and at Month 24. A mixed-effect model for repeated measures (MMRM) estimated changes in height and weight over time. Height and weight Z-scores were also analyzed by dose group (0.2-<0.3 mg/kg/day, 0.3-<0.5 mg/kg/day, and 0.5-0.7 mg/kg/day), averaged over time. RESULTS: At the time of analysis, 279 patients were treated with fenfluramine for ≥12 months; 128 were treated for ≥24 months. Relative to the reference population with DS, fenfluramine treatment for ≥12 months or for ≥24 months had minimal impact on height or weight over time as assessed by Z-score analyses. No substantial dose-dependent changes from baseline were observed at Month 12 nor at Month 24. MMRM showed that patients treated with fenfluramine for ≥12 months (N = 262) had an estimated change in Z-score per year of -0.056 for height and -0.166 for weight. For patients with data from all three time points (baseline, 12 months, and 24 months; N = 110), estimated changes in Z-scores per year were -0.025 for height and -0.188 for weight. MMRM projections based on normative reference growth curves were comparable to growth data from historical control populations with DS. SIGNIFICANCE/CONCLUSION: Long-term treatment with fenfluramine had minimal impact on the growth of patients with DS as demonstrated by differences in Z-scores for height and weight at 12 months and at 24 months. Changes in Z-scores for height and weight were consistent with published reports on patients with DS.

Efficacy, tolerability, and retention of fenfluramine for the treatment of seizures in patients with Dravet syndrome: Compassionate use program in Germany.

OBJECTIVE: Dravet syndrome (DS) is a rare but severe drug-resistant epilepsy. Before the approval of fenfluramine (FFA) for the treatment of seizures in DS, patients in Germany could receive treatment under a compassionate use program (CUP). METHODS: We conducted a multicenter, retrospective, observational study to describe the efficacy, tolerability, and retention of FFA within the CUP. Patients received add-on therapy with oral FFA gradually titrated to a target dose between .13 and .7 mg/kg/day. RESULTS: Overall, 78 patients with DS (median age = 8.0 years, range = 2.1-46.0; 53% female, median concomitant antiseizure medications [ASMs] = 3) were treated with FFA for a median duration of 255.5 days (range = 31-572). Responder rates (a ≥50% reduction; n = 78) and seizure-freedom rates at 3 months were 68% and 14% for total seizures, respectively, and 67% and 23% for generalized tonic-clonic seizures. Responder rates were consistent at 6 and 12 months (n = 66 and n = 43, respectively). Median seizure days per month significantly decreased from 10.0 (range = .5-30) to 3.0 (range = 0-30) in the 3-month period before and after FFA treatment (p < .001). Significantly fewer patients reported at least one episode of status epilepticus (28% vs. 14% patients before and after FFA initiation, p = .005). During FFA treatment, 35 (45%) patients were able to discontinue a concomitant ASM. At the last follow-up date, 66 (85%) patients remained on treatment with FFA. The most common adverse events were somnolence (36%), decreased appetite (22%), and ataxia (8%). Forty-eight (62%) patients were reported as having a meaningful global clinical improvement. SIGNIFICANCE: In a large cohort of patients, FFA demonstrated efficacy across a range of outcomes including clinically significant reductions in convulsive seizures, and was well tolerated, providing valuable information for real-world practice.

Epilepsy associated with tuberous sclerosis complex in childhood: Long-term outcome in children after epilepsy surgery and children non-eligible for epilepsy surgery.

OBJECTIVE: Drug-resistant epilepsy is one of the major disease burdens in patients with tuberous sclerosis complex (TSC). Epilepsy surgery has been shown to be effective in TSC, but making a decision for surgery is often more complex than in other surgically amenable epilepsy syndromes and not all patients with TSC are eligible. We investigated long-term outcomes (after ≥one year; median, 6.4 years) with a special interest in general developmental level, health-related quality of life, parental concerns due to epilepsy, impact on family, and social adaptation in children who underwent epilepsy surgery and in children who were not eligible for surgery. METHODS: Eighty-five children (median age at intervention: 3.3 years, interquartile range [IQR]: 1.8-6.3 years) with TSC-related epilepsy had a presurgical investigation, and 34 of this group underwent epilepsy surgery. At follow-up (median age: 11.5 years, IQR: 7.8-15.5 years), we assessed seizure outcome, health-related quality of life, social adaptation, parental concerns due to epilepsy, and general developmental level based on established questionnaires and a standardized interview. Generalized linear models were performed for statistical evaluation. RESULTS: At follow-up, 53% (18/34) of the operated patients were seizure free for ≥12 months and 30% (15/50) of the patients non-eligible for epilepsy surgery (p = 0.037). In the surgical group, developmental level was significantly higher in seizure-free patients, in comparison to non-seizure-free patients (p = 0.004); this was also observed in the non-surgical group, but less marked (p = 0.089). Furthermore, developmental level was significantly (p ≤ 0.001) related to quality of life, social adaptation, impact on family, and parental concerns. In both cohorts, parental concerns were less pronounced if children became seizure free (p < 0.001 and p = 0.018, respectively). SIGNIFICANCE: In children with TSC-related epilepsy, quality of life, social adaptation, and impact on family were related to general developmental level, which in turn was significantly related to seizure freedom. Consequent epilepsy management aiming at seizure freedom, including presurgical evaluation and, if indicated, epilepsy surgery in a center specifically experienced with TSC-related epilepsy, is a worthwhile effort to improve quality of life in patients with TSC and their families.