Search Results (70)

Dravet Syndrome (DS) is a severe genetic epileptic encephalopathy caused by mutations in the SCN1A gene that encodes the voltage-gated sodium channel (Na_V1.1) subunit alpha. DS is characterized by intractable seizures, progressive developmental delay, cognitive impairment, and high mortality due to sudden unexpected death in epilepsy (SUDEP). SUDEP is mediated by respiratory dysfunction, but the exact molecular underpinnings are unclear. Though hippocampal metabolic alterations have been reported in DS mice, such changes in brain regions controlling breathing have not been studied. We used Scn1a^A1783V/WT DS mice to study temporal alterations in the brain metabolome, including analysis of brainstem and forebrain regions. Glycolytic and pentose phosphate pathway intermediates were significantly elevated in the brainstem of DS mice during the period of enhanced susceptibility to mortality (post-natal days P20–30). In older P40–P50 mice, mitochondrial aconitate and the antioxidant glutathione were significantly elevated in the brainstem. Single-nuclei RNA sequencing (snRNA seq) and proteomic analyses revealed alterations in genes associated with neurotransmission, cellular respiration, and protein translation, as well as reorganization of protein kinase-mediated pathways that are specific to the brainstem. These findings suggest that there are widespread metabolic changes in the brainstem of DS mice. Full article

Mutations in the transcriptional co-factor HCFC1 cause methylmalonic aciduria and homocystinemia, cblX type (cblX) (MIM#309541), non-syndromic X-linked intellectual disability (XLID), and focal epilepsy. Zebrafish studies have revealed increased activation of the Akt/mTor signaling pathway after mutation of hcfc1a, one ortholog of HCFC1. mTOR hyperactivation is linked to seizures, and its inhibition alleviates epilepsy in other preclinical models. We hypothesized that mTor overactivity in hcfc1a mutant zebrafish increases seizure susceptibility and/or severity. We employed a two-concentration model of the seizure-inducing agent, pentylenetetrazol (PTZ), with or without pretreatment of the mTor inhibitor, torin1. Mutation of hcfc1a did not alter the response to PTZ at sub-optimal concentrations, and the pharmaceutical inhibition of mTor using the compound Torin1 reduced response to 1 µM PTZ, but only in a dose-dependent manner. Higher doses of mTor inhibition did not reduce the seizure response in mutant larvae but were effective in wildtype siblings. These data suggest that inhibition of mTor in an hcfc1a-deficient background leads to a reaction that differs from the traditional response observed in wildtype siblings. Collectively, we present a model that can be used to test dose–response and the development of combinatorial treatment approaches in a high-throughput manner. Full article

Microcephaly with early-onset, intractable seizures, and developmental delay (MCSZ) is a rare inherited neurological disorder caused by biallelic loss-of-function variants in the polynucleotide kinase/phosphatase (PNKP) gene, which encodes an enzyme critical for DNA repair. Here, we describe the clinical history of two novel patients presenting with microcephaly, epilepsy, growth deficiency, language impairment, and severe intellectual disability. Brain MRI in both cases revealed complex cerebral malformations, including lissencephaly, ventriculomegaly, dysmorphic hippocampi, and cerebellar atrophy. Next-generation sequencing (NGS) analyses identified compound heterozygous PNKP variants in both patients. In case #1, we detected the missense variant p.Gln50Glu (c.148C>G) in exon 2 (rs756746191) and a novel nonsense variant, p.Gln248Ter (c.742C>T), leading to a premature stop codon in exon 7. In case #2, we identified the frameshift variant p.Thr424GlyfsTer49, caused by a 17-nucleotide duplication (c.1253_1269dupGGGTCGCCATCGACAAC) in exon 14 (rs587784365), along with a 15-nucleotide deletion (c.1386+49_1387-33delCCTCCTCCCCTGACCCC) in intron 15 (rs752902474). Over long-term follow-up (20 and 36 years for case #1 and case #2, respectively), seizures persisted in the first patient, while full control was achieved in the second case with combined therapy of valproate and clobazam. Along with a review of the literature, these two novel cases confirm the broad phenotypic spectrum of PNKP-associated disorders and underscore the importance of including PNKP in the genetic screening of patients presenting with developmental and epileptic encephalopathy (DEE) and microcephaly. Full article

Lennox–Gastaut syndrome (LGS) is a severe form of childhood-onset epilepsy, often associated with pharmacoresistance. As complete seizure control is usually not achievable with the use of drug therapy, non-pharmacological treatment may be offered to intractable patients. In this review, we are going to present literature reports on various non-pharmacological treatments, including surgical and dietary methods. Surgical interventions, such as resective surgery, corpus callosotomy (CC), or neuromodulation therapies such as vagus nerve stimulation (VNS), deep brain stimulation (DBS), and responsive neurostimulation (RNS), can be offered to pharmacoresistant patients. If the epileptogenic area can be detected, resective surgery is a treatment of choice. On the contrary, if non-invasive and invasive diagnostic methods fail to detect epileptogenic lesions, CC and VNS are considered palliative surgical methods. While both CC and VNS are considered effective in seizure reduction, CC is still more popular than VNS, although VNS seems to be related to better tolerability. Although all neuromodulation therapies require multidirectional optimization, DBS appears to be particularly promising for LGS. The classic ketogenic diet (cKD) is considered an effective and well-tolerated method in LGS treatment. The modified Atkins diet (MAD) and the low glycemic index treatment (LGIT) could be used as valuable alternatives due to their lower restrictiveness and better tolerability. Moreover, combinations of several treatment methods could significantly improve LGS patients’ seizure outcomes. Full article

Cyclin-dependent kinase-like 5 (CDKL5) deficiency disorder (CDD) is a severe X-linked neurodevelopmental condition characterized by early-onset, intractable epilepsy, motor and cognitive impairment, and autistic-like features. Although constitutive Cdkl5 knockout (KO) models have established the importance of CDKL5 during early brain development, CDKL5’s role in the mature brain remains poorly defined. Here, we employed an inducible, conditional KO model in which Cdkl5 is selectively deleted from forebrain glutamatergic neurons in adult mice to investigate the postdevelopmental functions of CDKL5. Using a total of 48 adult male mice, including Cdkl5^flox/Y(Cre⁺) (n = 30) and Cdkl5^flox/Y(Cre⁻) littermate controls (n = 18), we found that tamoxifen-induced Cdkl5 deletion led to prominent behavioral impairments, including deficits in motor coordination, reduced sociability, and impaired hippocampus-dependent spatial memory, while behavioral features such as hyperactivity and stereotypic jumping, typically present in germline KOs, were absent. Sensory functions, including olfaction and pain perception, were also preserved. At the cellular level, the loss of Cdkl5 resulted in a marked reduction in excitatory synapse density in the cortex and hippocampus, accompanied by increased numbers of immature dendritic spines and decreased mature spines. Neuronal loss in the hippocampal CA1 region and selective microglial activation in the cortex were also observed. These alterations closely resemble those seen in constitutive KO models, underscoring the ongoing requirement for CDKL5 expression in excitatory neurons for maintaining synaptic integrity and neuronal homeostasis in the adult brain. This study underscores the importance of temporally controlled models for investigating the mechanisms underlying CDD pathophysiology in the adult brain. Full article

Vagal nerve stimulators (VNSs) improve seizure control in up to half of the patients who have them implanted. In non-responding patients, VNS removal may be necessary. Removal is traditionally accomplished through two incisions. We present our experience removing VNSs through a single incision. Background/Objectives: To determine if VNS removal can be safely performed through a single incision. Methods: The medical records of 73 consecutive patients who underwent VNS removal at our institution from 2012 to 2024 were reviewed. Patients were divided into single-incision and two-incision treatment groups. Operative time and surgical complications were compared between groups. Results: A total of 73 patients underwent VNS removal during the study timeframe. Forty-eight VNS removals were accomplished via a single incision, while 25 required both incisions. Time in the operating room was roughly half as long for single-incision removal vs. two-incision removal (29.4 min, range 11–84 vs. 74.2 min, range 33–203); however, single incision was initially attempted in all cases. In two of the incision cases, the neck dissection resulted in an injury to the internal jugular (IJ) vein. In one case, the IJ was repaired and the lead wire removed. In a second case, the IJ could not be repaired, and a segment of lead wire was retained. In a third case, a short length of lead wire was discovered after a single-incision removal and a second procedure was necessary for removal. There were no significant differences in the rates of transient vocal cord weakness, cough, and/or dysphagia between both treatment groups (p = 0.7368), and there were no cases of permanent nerve palsy. Conclusions: VNS removal can be safely accomplished via a single incision in most cases. Successful single-incision procedures may be shorter than the two-incision approach. Attempted VNS removal via a single incision may result in increased incidence of transient hoarseness, dysphagia, and/or cough, but may result in reduced rates of permanent injury or IJ injury. Full article

Epilepsy is widely known as a network disease. Ictal and interictal activities are generated and spread within the existing networks involving different regions of the brain. Network alterations affect both grey and white matter, deep brain nuclei, including those of the ascending reticular formation. These structures may be involved in a disorganized connectome associated with epilepsy. A growing body of neuroimaging and neuropsychological findings suggests that global and focal network aberrations are closely linked to cognitive deficits in epilepsy patients. This evidence relates equally to focal epilepsies, such as temporal lobe epilepsy or extra-temporal lobe epilepsy, as well as generalized epilepsies, such as juvenile myoclonic epilepsy. Network abnormalities have been associated with a broad range of cognitive impairments, including language, memory, and executive functions, as well as sensory and motor functions. Whole-brain structural connectome models help in the understanding of seizure generation and spread. Identifying key nodes of seizure propagation may help in planning surgical procedures in individual patients by simulating epilepsy surgery on virtual models. Functional connectomic profiles may predict seizure outcomes in patients who undergo deep brain stimulation due to intractable seizures. Therefore, individualized interventional strategies could be developed based on connectome characteristics. Full article

The ketogenic diet (KD) is a dietary intervention comprising a high-fat, low-carbohydrate, and moderate-protein intake designed to induce a metabolic state known as ketosis, whereby ketone bodies are produced as an alternative source of energy. Initially established as a treatment for intractable epilepsy, the KD has subsequently gained significant attention for its potential to manage neurodegenerative diseases, including Alzheimer’s, Parkinson’s, and Huntington’s disease. Ketone bodies, such as beta-hydroxybutyrate (BHB), have been demonstrated to possess neuroprotective properties. The increasing prevalence of neurodegenerative diseases, such as Alzheimer’s, Parkinson’s, and Huntington’s disease, poses a significant public health challenge worldwide. With neurological disorders being the second-leading cause of death globally, the need for effective therapeutic interventions has never been more urgent. Recent evidence suggests that dietary interventions, particularly the ketogenic diet, offer promising potential in mitigating the progression of these diseases by influencing metabolic processes and providing neuroprotective benefits. The ketogenic diet, characterized by high-fat and low-carbohydrate intake, induces ketosis, leading to the production of ketone bodies like beta-hydroxybutyrate, which enhance mitochondrial efficiency, reduce oxidative stress, and modulate inflammatory pathways—mechanisms critical in neurodegenerative pathophysiology. This review explores the role of the ketogenic diet in managing neurological conditions, examining its mechanisms of action, historical context, and therapeutic efficacy. The paper also discusses emerging evidence linking the ketogenic diet to improved cognitive function, reduced motor symptoms, and enhanced mitochondrial activity in patients with neurodegenerative disorders. Additionally, the review highlights the need for further research to refine the therapeutic applications of the ketogenic diet, investigate its impact on various neurodegenerative diseases, and better understand its potential long-term effects. This study underscores the importance of nutrition as a vital aspect of the treatment strategy for neurological diseases, advocating for continued exploration of dietary interventions to improve brain health and function. Full article

Background: The nuclear-encoded enzyme polymerase gamma (Pol-γ) is crucial in the replication of the mitochondrial genome (mtDNA), which in turn is vital for mitochondria and hence numerous metabolic processes and energy production in eukaryotic cells. Variants in the POLG gene, which encodes the catalytic subunit of Pol-γ, can significantly impair Pol-γ enzyme function. Pol-γ-associated disorders are referred to as POLG-spectrum disorders (POLG-SDs) and are mainly autosomal-recessively inherited. Clinical manifestations include muscle weakness and fatigue, and severe forms of the disease can lead to premature death in infancy, childhood, and early adulthood, often associated with seizures, liver failure, or intractable epilepsy. Here, we analyzed fibroblasts from a compound heterozygous patient with the established pathogenic variant c.2419C>T; p.(Arg807Cys) and a previously undescribed variant c.678G>C; p.(Gln226His) with a clinical manifestation compatible with POLG-SDs, sensory ataxic neuropathy, and infantile muscular atrophy. We conducted a battery of functional studies for Pol-γ and mitochondrial dysfunction on the patient’s fibroblasts, to test whether the novel variant c.678G>C; p.(Gln226His) may be causative in human disease. Aims/Methods: We analyzed skin-derived fibroblasts in comparison to a first-degree relative (the mother of the patient), an asymptomatic carrier harboring only the established c.2419C>T; p.(Arg807Cys) mutation. Assessments of mitochondrial function included measurements of mtDNA content, mRNA levels of mitochondrial genes, mitochondrial mass, and mitochondrial morphology. Case Presentation and Results: A 13-year-old male presented with symptoms starting at three years of age, including muscle weakness and atrophy in the lower extremities and facial muscles, which later extended to the upper limbs, voice, and back muscles, without further progression. The patient also reported fatigue and muscle pain after physical activity, with no sensory deficits. Extensive diagnostic tests such as electromyography, nerve conduction studies, muscle biopsy, and MRI were unremarkable. Exome sequencing revealed that he carried the compound heterozygous variants in POLG c.678G>C; p.(Gln226His) and c.2419C>T; p.(Arg807Cys), but no other potential genetic pathogenic causes. In comparison to a first-degree relative (his mother) who only carried the c.2419C>T; p.(Arg807Cys) pathogenic mutation, in vitro analyses revealed a significant reduction in mtDNA content (~50%) and mRNA levels of mtDNA-encoded proteins. Mitochondrial mass was reduced by approximately 20%, and mitochondrial interconnectivity within cells was impaired, as determined by fluorescence microscopy and mitochondrial staining. Conclusions: Our findings suggest that the c.678G>C; p.(Gln226His) variant, in conjunction with the c.2419C>T; p.(Arg807Cys) mutation, may compromise mtDNA replication and mitochondrial function and could result in clinically significant mitochondriopathy. As this study is based on one patient compared to a first-degree relative (but with an identical mitochondrial genome), the pathogenicity of c.678G>C; p.(Gln226His) of POLG should be confirmed in future studies, in particular, in conjunction with other POLG-variants. Full article

Oxidative stress develops when there is an excess of oxidants leading to molecular and cellular damage. Seizure activity leads to oxidative stress and the resulting increased lipid peroxidation. Generally, antiseizure medications reduce oxidative stress, although the data on levetiracetam are ambiguous. Exogenous antioxidants (vitamin E, resveratrol, hesperidin, and curcumin) have been documented to exert an anticonvulsant effect in animal models of seizures and some recent clinical data point to curcumin as an affective adjuvant for the therapy of pediatric intractable epilepsy. Melatonin is an antioxidant with an ability to attenuate seizure activity induced by various convulsants in rodents. Its clinical effectiveness has been also confirmed in a number of clinical studies. Experimental studies point to a possibility that endogenous melatonin may possess proconvulsive activity. Moreover, some scarce clinical data seem to express this view; however, a limited number of patients were included. The anticonvulsant activity of exogenous melatonin may involve GABA-mediated inhibition, while endogenous melatonin may act as a proconvulsant due to a decrease in the brain dopaminergic transmission. Antioxidants, including melatonin, may be considered as adjuvants in the therapy of epilepsy and melatonin, in addition, in patients with epilepsy suffering from sleep disorders. Full article

Advances in genetics led to the identification of hundreds of epilepsy-related genes, some of which are treatable with etiology-specific interventions. However, the diagnostic yield of next-generation sequencing (NGS) in unexplained epilepsy is highly variable (10–50%). We sought to determine the diagnostic yield and clinical utility of NGS in children with unexplained epilepsy that is accompanied by neurodevelopmental delays and/or is medically intractable. A 5-year retrospective review was conducted at the American University of Beirut Medical Center to identify children who underwent whole exome sequencing (WES) or whole genome sequencing (WGS). Data on patient demographics, neurodevelopment, seizures, and treatments were collected. Forty-nine children underwent NGS with an overall diagnostic rate of 68.9% (27/38 for WES, and 4/7 for WGS). Most children (42) had neurodevelopmental delays with (18) or without (24) refractory epilepsy, and only three had refractory epilepsy without delays. The diagnostic yield was 77.8% in consanguineous families (18), and 61.5% in non-consanguineous families (26); consanguinity information was not available for one family. Genetic test results led to anti-seizure medication optimization or dietary therapies in six children, with subsequent improvements in seizure control and neurodevelopmental trajectories. Not only is the diagnostic rate of NGS high in children with unexplained epilepsy and neurodevelopmental delays, but also genetic testing in this population may often lead to potentially life-altering interventions. Full article

Population-based data on drug-resistant epilepsy (DRE) are lacking. This retrospective study aimed to determine the prevalence and incidence of pediatric epilepsy and DRE in South Korea using health insurance claims data from the Health Insurance Review and Assessment Service (2013–2022). Epilepsy and DRE prevalence and incidence in children <18 years old were estimated over time and by age and sex. Results showed that the age-standardized prevalence and incidence rates of epilepsy increased. The age-standardized prevalence rate of DRE increased, while the age-standardized incidence rate remained unchanged. The standardized prevalence rate of DRE was 0.26 per 1000 persons, and the average standardized incidence rate of DRE was 0.06 per 1000 persons. The prevalence rate of DRE gradually increased with age, with age 0 demonstrating the highest incidence rate. The prevalence of generalized DRE was the highest across all ages, and incidence was the highest at 0 years. Conversely, the incidence of focal DRE did not change with age. Our study revealed a stable incidence rate of DRE in Korea, despite increased prevalence. DRE incidence was the highest in the first year of life, with the generalized type being the most prevalent. Full article

Epilepsy is one of the most disabling neurological diseases. Despite proper pharmacotherapy and the availability of 2nd and 3rd generation antiepileptic drugs, deep brain stimulation, and surgery, up to 30–40% of epilepsy patients remain drug-resistant. Consequences of this phenomenon include not only decreased a quality of life, and cognitive, behavioral, and personal disorders, but also an increased risk of death, i.e., in the mechanism of sudden unexpected death in epilepsy patients (SUDEP). The main goals of epilepsy treatment include three basic issues: achieving the best possible seizure control, avoiding the undesired effects of treatment, and maintaining/improving the quality of patients’ lives. Therefore, numerous attempts are made to offer alternative treatments for drug-resistant seizures, an example of which is the ketogenic diet. It is a long-known but rarely used dietary therapy for intractable seizures. One of the reasons for this is the unpalatability of the classic ketogenic diet, which reduces patient compliance and adherence rates. However, its antiseizure effects are often considered to be worth the effort. Until recently, the diet was considered the last-resort treatment. Currently, it is believed that a ketogenic diet should be used much earlier in patients with well-defined indications. In correctly qualified patients, seizure activity may be reduced by over 90% or even abolished for long periods after the diet is stopped. A ketogenic diet can be used in all age groups, although most of the available literature addresses pediatric epilepsy. In this article, we focus on the mechanisms of action, effectiveness, and adverse effects of different variants of the ketogenic diet, including its classic version, a medium-chain triglyceride diet, a modified Atkins diet, and a low glycemic index treatment. Full article

In humans and animal models, temporal lobe epilepsy (TLE) is associated with reorganization of hippocampal neuronal networks, gliosis, neuroinflammation, and loss of integrity of the blood–brain barrier (BBB). More than 30% of epilepsies remain intractable, and characterization of the molecular mechanisms involved in BBB dysfunction is essential to the identification of new therapeutic strategies. In this work, we induced status epilepticus in rats through injection of the proconvulsant drug pilocarpine, which leads to TLE. Using RT-qPCR, double immunohistochemistry, and confocal imaging, we studied the regulation of reactive glia and vascular markers at different time points of epileptogenesis (latent phase—3, 7, and 14 days; chronic phase—1 and 3 months). In the hippocampus, increased expression of mRNA encoding the glial proteins GFAP and Iba1 confirmed neuroinflammatory status. We report for the first time the concomitant induction of the specific proteins CD31, PDGFRβ, and ColIV—which peak at the same time points as inflammation—in the endothelial cells, pericytes, and basement membrane of the BBB. The altered expression of these proteins occurs early in TLE, during the latent phase, suggesting that they could be associated with the early rupture and pathogenicity of the BBB that will contribute to the chronic phase of epilepsy. Full article

We report the case of a four-year-old male patient with a complex medical history born prematurely as the result of intrauterine growth restriction due to placental insufficiency. His clinical manifestations included severe neurodevelopmental deficits, global developmental delay, Pierre-Robin sequence, and intractable epilepsy with both generalized and focal features. The proband’s low levels of citrulline and lactic acidosis provoked by administration of Depakoke were evocative of a mitochondrial etiology. The proband’s genotype–phenotype correlation remained undefined in the absence of nuclear and mitochondrial pathogenic variants detected by deep sequencing of both genomes. However, live-cell mitochondrial metabolic investigations provided evidence of a deficient oxidative-phosphorylation pathway responsible for adenosine triphosphate (ATP) synthesis, leading to chronic energy crisis in the proband. In addition, our metabolic analysis revealed metabolic plasticity in favor of glycolysis for ATP synthesis. Our mitochondrial morphometric analysis by transmission electron microscopy confirmed the suspected mitochondrial etiology, as the proband’s mitochondria exhibited an immature morphology with poorly developed and rare cristae. Thus, our results support the concept that suboptimal levels of intrauterine oxygen and nutrients alter fetal mitochondrial metabolic reprogramming toward oxidative phosphorylation (OXPHOS) leading to a deficient postnatal mitochondrial energy metabolism. In conclusion, our collective studies shed light on the long-term postnatal mitochondrial pathophysiology caused by intrauterine growth restriction due to idiopathic placental insufficiency and its negative impact on the energy-demanding development of the fetal and postnatal brain. Full article