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.

Genome Sequencing for Diagnosing Rare Diseases.

BACKGROUND: Genetic variants that cause rare disorders may remain elusive even after expansive testing, such as exome sequencing. The diagnostic yield of genome sequencing, particularly after a negative evaluation, remains poorly defined. METHODS: We sequenced and analyzed the genomes of families with diverse phenotypes who were suspected to have a rare monogenic disease and for whom genetic testing had not revealed a diagnosis, as well as the genomes of a replication cohort at an independent clinical center. RESULTS: We sequenced the genomes of 822 families (744 in the initial cohort and 78 in the replication cohort) and made a molecular diagnosis in 218 of 744 families (29.3%). Of the 218 families, 61 (28.0%) - 8.2% of families in the initial cohort - had variants that required genome sequencing for identification, including coding variants, intronic variants, small structural variants, copy-neutral inversions, complex rearrangements, and tandem repeat expansions. Most families in which a molecular diagnosis was made after previous nondiagnostic exome sequencing (63.5%) had variants that could be detected by reanalysis of the exome-sequence data (53.4%) or by additional analytic methods, such as copy-number variant calling, to exome-sequence data (10.8%). We obtained similar results in the replication cohort: in 33% of the families in which a molecular diagnosis was made, or 8% of the cohort, genome sequencing was required, which showed the applicability of these findings to both research and clinical environments. CONCLUSIONS: The diagnostic yield of genome sequencing in a large, diverse research cohort and in a small clinical cohort of persons who had previously undergone genetic testing was approximately 8% and included several types of pathogenic variation that had not previously been detected by means of exome sequencing or other techniques. (Funded by the National Human Genome Research Institute and others.).

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.

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.

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.

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.

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.

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.

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.

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.

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.

Variants in GNAI1 cause a syndrome associated with variable features including developmental delay, seizures, and hypotonia.

PURPOSE: Neurodevelopmental disorders (NDDs) encompass a spectrum of genetically heterogeneous disorders with features that commonly include developmental delay, intellectual disability, and autism spectrum disorders. We sought to delineate the molecular and phenotypic spectrum of a novel neurodevelopmental disorder caused by variants in the GNAI1 gene. METHODS: Through large cohort trio-based exome sequencing and international data-sharing, we identified 24 unrelated individuals with NDD phenotypes and a variant in GNAI1, which encodes the inhibitory Gαi1 subunit of heterotrimeric G-proteins. We collected detailed genotype and phenotype information for each affected individual. RESULTS: We identified 16 unique variants in GNAI1 in 24 affected individuals; 23 occurred de novo and 1 was inherited from a mosaic parent. Most affected individuals have a severe neurodevelopmental disorder. Core features include global developmental delay, intellectual disability, hypotonia, and epilepsy. CONCLUSION: This collaboration establishes GNAI1 variants as a cause of NDDs. GNAI1-related NDD is most often characterized by severe to profound delays, hypotonia, epilepsy that ranges from self-limiting to intractable, behavior problems, and variable mild dysmorphic features.

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.

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.

Hyperkinetic Seizures with Ictal Fear as Localizing Ictal Signs in MRI-Negative Medial Frontal Lobe Epilepsy.

PURPOSE: Hyperkinetic seizures are described as seizure onset in the frontal or temporal lobe. Additional localizing information is important for diagnostic workup and surgical therapy. We describe diagnostic workup and surgical outcomes in three patients with pharmacoresistant focal emotional seizures with hyperkinetic elements. METHODS/RESULTS: High-resolution 3 Tesla (T) magnetic resonance imaging (MRI) did not reveal clear-cut lesions. Invasive video-electroencephalography (EEG) with depth electrodes along the cingulate sulcus (bilateral; patients 1 and 3), right; patient 2 provided congruent results for a circumscribed seizure onset zone within the medial frontal lobe (right: patients 1 and 2; left: patient 3). Topectomies were performed in all patients. Histopathology revealed a small focal cortical dysplasia in the three cases (focal cortical dysplasia [FCD] IIA: patient 1; FCD IIB: patients 2 and 3). All patients remained completely seizure-free since surgery (Engel 1A; follow-up: 9-28 months). CONCLUSION: Ictal fear associated with hyperkinetic semiology points to a seizure-onset zone within the anteromedial frontal lobe (anterior cingulate gyrus). Ictal semiology is crucial for the placement of depth electrodes, especially in MRI-negative cases. These cases illustrate a clinical advantage to the new International League against Epilepsy (ILAE) seizure classification, emphasizing initial clinical symptoms.

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.

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.

Improved everyday executive functioning following profound reduction in seizure frequency with fenfluramine: Analysis from a phase 3 long-term extension study in children/young adults with Dravet syndrome.

OBJECTIVE: Individuals with Dravet syndrome (DS) experience frequent pharmacoresistant seizures beginning in infancy. Most exhibit poor neurodevelopmental outcomes including motor function difficulties, behavior problems, and cognitive impairment. Cognitive deficits in children with DS have been associated with seizure frequency and antiseizure medication (ASM) use. Recent research in children and young adults with DS has begun to examine the role of executive functions (EFs), as these include higher-order cognitive functions and may mediate the relationship between risk factors and cognitive impairment. Current conceptualizations, however, of EFs involve the broader self-regulation of cognitive, behavioral, and emotional domains. We explored relationships between reduction in convulsive seizure frequency and everyday EFs in a subset of children and young adults with DS treated with adjunctive fenfluramine for 1 year. METHODS: This is a post-hoc analysis of data from children and young adults with Dravet syndrome aged 5-18 years who participated in a phase 3 randomized, placebo-controlled clinical trial (core study) followed by completion of at least 1 year of fenfluramine treatment in an open-label extension (OLE) study. Eligible children and young adults started the OLE study at 0.2 mg/kg/day fenfluramine and were titrated to optimal seizure control and tolerability (maximum daily dose: 26 mg/day). Parents/caregivers documented convulsive seizure frequency per 28 days (i.e., monthly convulsive seizure frequency [MCSF]) by electronic diary. A parent/caregiver for each child also completed the Behavior Rating Inventory of Executive Function (BRIEF®) parent form, a questionnaire capturing parents'/caregivers' perceptions of everyday EF that was included as a safety measure to assess treatment-related adverse effects on EF during the trial. Ratings on BRIEF® were mapped to the current edition, the BRIEF®2 parent form, and were used to calculate T-scores for the Behavior Regulation Index (BRI), Emotion Regulation Index (ERI), Cognitive Regulation Index (CRI), and Global Executive Composite (GEC). Change in BRIEF®2 T-scores from baseline in the core study to Year 1 of the OLE study was calculated. Spearman's rho correlation coefficients assessed associations between change in BRIEF®2 indexes/composite T-scores and percentage change in MCSF. Children and young adults were divided into 2 groups based on percentage of MCSF reduction achieved from pre-randomization baseline in the core study to Year 1 of the OLE study: <50% and ≥50% MCSF reduction. Changes in the distribution of BRIEF®2 indexes/composite T-scores were compared between MCSF reduction groups using Mann-Whitney U tests. The proportions of children and young adults in these groups who showed clinically meaningful improvement in everyday EF, defined as Reliable Change Index (RCI) values ≥95% certainty relative to a reference population of neurotypically developing healthy volunteers, were then assessed by cross-tabulations and Somers' D tests (p ≤ 0.05). When there was a significant meaningful improvement in an index score, post-hoc analyses using the same statistical methods were conducted to evaluate the individual BRIEF®2 scales composing that index. Supplemental analyses examined the proportions of patients in MCSF reduction groups <25% and ≥75% who achieved clinically meaningful improvement or worsening in everyday EF using RCI values ≥95% certainty and ≥80% certainty, respectively, relative to the reference population. RESULTS: At the time of analysis, 58 children and young adults (mean age: 11 ±â€¯4 years) had reached OLE Year 1 of fenfluramine treatment with a 75% median percentage reduction in seizure frequency from pre-randomization baseline. Overall, there was a significant correlation between change in MCSF and change in BRIEF®2 T-scores for ERI (p = 0.008), but not for BRI, CRI, or GEC (p > 0.05). At OLE Year 1, 78% (n = 45) of total children/young adults had ≥50% MCSF reduction (50% [n = 29] achieved ≥75% MCSF reduction) and 22% (n = 13) of total children/young adults had <50% MCSF reduction (12% [n = 7] showed <25% MCSF reduction). The ≥50% MCSF reduction group was significantly more likely to achieve clinically meaningful improvement (RCI ≥ 95% certainty) in ERI (p = 0.002) and in CRI (p = 0.001) than the <50% MCSF reduction group. There were no significant differences in the proportions of children and young adults in the 2 MCSF reduction groups showing clinically meaningful worsening (RCI ≥ 80% certainty) on the BRIEF®2 indexes/composite. SIGNIFICANCE: In children and young adults with DS, the magnitude of reduction in MCSF after long-term treatment with adjunctive fenfluramine was associated with clinically meaningful levels of improvement in everyday EF. Seventy-eight percent (78%) of children and young adults treated with adjunctive fenfluramine for 1 year in the OLE study achieved ≥50% reduction in MCSF, for a magnitude of efficacy associated with a significantly greater likelihood of experiencing clinically meaningful improvement in emotion regulation and cognitive regulation.

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.

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

BACKGROUND: Dravet syndrome is a rare, treatment-resistant developmental epileptic encephalopathy characterised by multiple types of frequent, disabling seizures. Fenfluramine has been reported to have antiseizure activity in observational studies of photosensitive epilepsy and Dravet syndrome. The aim of the present study was to assess the efficacy and safety of fenfluramine in patients with Dravet syndrome. METHODS: In this randomised, double-blind, placebo-controlled clinical trial, we enrolled children and young adults with Dravet syndrome. After a 6-week observation period to establish baseline monthly convulsive seizure frequency (MCSF; convulsive seizures were defined as hemiclonic, tonic, clonic, tonic-atonic, generalised tonic-clonic, and focal with clearly observable motor signs), patients were randomly assigned through an interactive web response system in a 1:1:1 ratio to placebo, fenfluramine 0·2 mg/kg per day, or fenfluramine 0·7 mg/kg per day, added to existing antiepileptic agents for 14 weeks. The primary outcome was the change in mean monthly frequency of convulsive seizures during the treatment period compared with baseline in the 0·7 mg/kg per day group versus placebo; 0·2 mg/kg per day versus placebo was assessed as a key secondary outcome. Analysis was by modified intention to treat. Safety analyses included all participants who received at least one dose of study medication. This trial is registered with ClinicalTrials.gov with two identical protocols NCT02682927 and NCT02826863. FINDINGS: Between Jan 15, 2016, and Aug 14, 2017, we assessed 173 patients, of whom 119 patients (mean age 9·0 years, 64 [54%] male) were randomly assigned to receive either fenfluramine 0·2 mg/kg per day (39), fenfluramine 0·7 mg/kg per day (40) or placebo (40). During treatment, the median reduction in seizure frequency was 74·9% in the fenfluramine 0·7 mg/kg group (from median 20·7 seizures per 28 days to 4·7 seizures per 28 days), 42·3% in the fenfluramine 0·2 mg/kg group (from median 17·5 seizures per 28 days to 12·6 per 28 days), and 19·2% in the placebo group (from median 27·3 per 28 days to 22·0 per 28 days). The study met its primary efficacy endpoint, with fenfluramine 0·7 mg/kg per day showing a 62·3% greater reduction in mean MCSF compared with placebo (95% CI 47·7-72·8, p<0·0001); fenfluramine 0·2 mg/kg per day showed a 32·4% reduction in mean MCSF compared with placebo (95% CI 6·2-52·3, p=0·0209). The most common adverse events (occurring in at least 10% of patients and more frequently in the fenfluramine groups) were decreased appetite, diarrhoea, fatigue, lethargy, somnolence, and decreased weight. Echocardiographic examinations revealed valve function within the normal physiological range in all patients during the trial and no signs of pulmonary arterial hypertension. INTERPRETATION: In Dravet syndrome, fenfluramine provided significantly greater reduction in convulsive seizure frequency compared with placebo and was generally well tolerated, with no observed valvular heart disease or pulmonary arterial hypertension. Fenfluramine could be an important new treatment option for patients with Dravet syndrome. FUNDING: Zogenix.