Search Results (405)

Schizophrenia (SZ) is a complex neuropsychiatric disorder characterized by heterogeneous symptoms, relatively poor clinical outcome, and widespread disruptions in neural connectivity and oscillatory dynamics. This article attempts to review current evidence linking genomic and proteomic alterations with aberrant neural oscillations observed in SZ, including aberrations in all oscillatory frequency bands obtained via human EEG. The numerous genes discussed are mainly involved in modulating synaptic transmission, synaptic function, interneuron excitability, and excitation/inhibition balance, thereby influencing the generation and synchronization of neural oscillations at specific frequency bands (e.g., gamma frequency band) critical for different cognitive, emotional, and perceptual processes in humans. The review highlights how polygenic influences and gene–circuit interactions underlie the neural oscillatory and connectivity abnormalities central to SZ pathophysiology, providing a framework for future research on common genetic-neural function interactions and on potential therapeutic interventions targeting local and global network-level neural dysfunction in SZ patients. As will be discussed, many of these genes affecting neural oscillations in SZ also affect other neurological disorders, ranging from autism to epilepsy. In time, it is hoped that future research will show why the same genetic anomaly leads to one illness in one person and to another illness in a different person. Full article

Background: Spectrin proteins are critical cytoskeleton components that maintain cellular structure and mediate intracellular transport. Pathogenic variants in SPTBN1, encoding βII-spectrin, have been associated with various neurodevelopmental disorders, including developmental delay, intellectual disability, autism spectrum disorder, and epilepsy. Here we report a Korean infant with infantile epileptic spasms syndrome (IESS) and an SPTBN1 mutation and provide a review of this mutation. Methods: The genomic data of the patient were analyzed by whole exome sequencing. A comprehensive literature review was conducted to identify and analyze all reported SPTBN1 variants, resulting in a dataset of 60 unique mutations associated with neurodevelopmental phenotypes. Case Presentation: A 10-month-old Korean female presented with IESS associated with a de novo heterozygous SPTBN1 mutation (c.785A>T; p.Asp262Val). The patient exhibited global developmental delay, microcephaly, hypotonia, spasticity, and MRI findings of diffuse cerebral atrophy and corpus callosum hypoplasia. Electroencephalography revealed hypsarrhythmia, confirming the diagnosis of IESS. Seizures persisted despite initial treatment with vigabatrin and steroids. Genetic analysis identified a likely pathogenic variant within the calponin homology 2 (CH2) domain of SPTBN1. Conclusions: This is the first report of an association between IESS and an SPTBN1 CH2 domain mutation in a Korean infant. This finding expands the clinical spectrum of SPTBN1-related disorders and suggests domain-specific effects may critically influence phenotypic severity. Further functional studies are warranted to elucidate the pathogenic mechanisms of domain-specific variants. Full article

Sudden Unexpected Death in Epilepsy (SUDEP) is a leading cause of mortality among individuals with epilepsy, particularly those with drug-resistant forms. This review explores the complex multisystem mechanisms underpinning SUDEP, integrating recent findings on brain, cardiac, and pulmonary dysfunctions. Background/Objectives: The main objective of this review is to elucidate how seizures disrupt critical physiological systems, especially the brainstem, heart, and lungs, contributing to SUDEP, with emphasis on respiratory control failure and autonomic instability. Methods: The literature from experimental models, clinical observations, neuroimaging studies, and genetic analyses was systematically examined. Results: SUDEP is frequently preceded by generalized tonic–clonic seizures, which trigger central and obstructive apnea, hypoventilation, and cardiac arrhythmias. Brainstem dysfunction, particularly in areas such as the pre-Bötzinger complex and nucleus tractus solitarius, plays a central role. Genetic mutations affecting ion channels (e.g., SCN1A, KCNQ1) and neurotransmitter imbalances (notably serotonin and GABA) exacerbate autonomic dysregulation. Risk is compounded by a prone sleeping position, reduced arousal capacity, and impaired ventilatory responses. Conclusions: SUDEP arises from a cascade of interrelated failures in respiratory and cardiac regulation initiated by seizure activity. The recognition of modifiable risk factors, implementation of monitoring technologies, and targeted therapies such as serotonergic agents may reduce mortality. Multidisciplinary approaches integrating neurology, cardiology, and respiratory medicine are essential for effective prevention strategies. Full article

Background/Objectives: Wolf–Hirschhorn syndrome (WHS; OMIM #194190) is a rare neurodevelopmental disorder, caused by deletions in the distal short arm of chromosome 4. It is characterized by developmental delay, epilepsy, intellectual disability, and distinctive facial dysmorphism. Clinical presentation varies widely, complicating prognosis and individualized care. Methods: We assembled a cohort of 140 individuals with genetically confirmed WHS from Spain and Latin-America, and developed and validated a multidimensional, Clinician-Reported Outcome Assessment (ClinRO) based on the Global Functional Assessment of the Patient (GFAP), derived from standardized clinical questionnaires and weighted by HPO (Human Phenotype Ontology) term frequencies. The GFAP score quantitatively captures key functional domains in WHS, including neurodevelopment, epilepsy, comorbidities, and age-corrected developmental milestones (selected based on clinical experience and disease burden). Results: Higher GFAP scores are associated with worse clinical outcomes. GFAP showed strong correlations with deletion size, presence of additional genomic rearrangements, sex, and epilepsy severity. Ward’s clustering and discriminant analyses confirmed GFAP’s discriminative power, classifying over 90% of patients into clinically meaningful groups with different prognoses. Conclusions: Our findings support GFAP as a robust, WHS-specific ClinRO that may aid in stratification, prognosis, and clinical management. This tool may also serve future interventional studies as a standardized outcome measure. Beyond its clinical utility, GFAP also revealed substantial social implications. This underscores the broader socioeconomic burden of WHS and the potential value of GFAP in identifying high-support families that may benefit from targeted resources and services. Full article

Objectives: The primary objective of this study was to determine whether motor disorders are significantly more prevalent in children with Autism Spectrum Disorder (ASD) without co-occurring genetic or neurological conditions compared to neurotypical children. Another aim was to explore the applicability of the MABC-2 test for assessing motor skills in a Polish cohort of children with ASD. Additionally, this study sought to develop a basic framework for motor skill assessment in children with autism. Methods: This study included 166 Caucasian children, both sexes, aged 5–12 years, without intellectual disability (IQ ≥ 70), without concomitant genetic or neurological disorders, particularly epilepsy or cerebral palsy. The study group consisted of children with ASD (n = 71), and the control group consisted of neurotypical children (n = 95). The participants were assessed with the Movement Assessment Battery for Children–second edition (MABC-2), MABC-2 checklist and the Developmental Coordination Disorder Questionnaire (DCDQ), used as a reference point. Results: The children with ASD obtained significantly lower MABC-2 test results in all subtests in comparison with the control group. The children with suspected or diagnosed coordination disorders were characterized by a significantly greater number of co-occurring non-motor factors than the other participants of this study. MABC-2 test showed greater consistency with DCDQ than with the MABC-2 questionnaire. Conclusions: Children with ASD present a lower level of manual dexterity and balance and greater difficulties in performing tasks, including throwing and catching, in comparison with neurotypical children. The MABC-2 test with the MABC-2 checklist and DCDQ questionnaire constitute a complementary diagnostic tool. Full article

Background: Developmental delay and intellectual disability (DD/ID) are frequently accompanied by epilepsy, and growing evidence implicates variants in voltage-gated calcium channel genes in their pathogenesis. This study aimed to investigate the association of polymorphisms in CACNA1A, CACNA1C, and CACNA1H with DD/ID and epilepsy comorbidity in Korean children. Methods: We retrospectively analyzed 141 pediatric patients diagnosed with DD/ID who underwent whole-exome sequencing (WES) and were not found to have pathogenic monogenic variants. Nine single-nucleotide polymorphisms (SNPs) across CACNA1A, CACNA1C, and CACNA1H were selected based on functional annotation scores and prior literature. Genotype data were extracted from WES variant files, and allele and genotype frequencies were compared with control data from the gnomAD East Asian population and the Korean Reference Genome Database (KRGDB). Subgroup analyses were performed according to epilepsy comorbidity. Results: The CACNA1A rs16023 variant showed a significantly higher B allele frequency in DD/ID patients than in both control datasets and was also associated with epilepsy comorbidity. Genotype distribution analysis revealed that the BB genotype of rs16023 was more frequent in patients with epilepsy. Conclusions: The CACNA1A rs16023 variant may contribute to genetic susceptibility to DD/ID and epilepsy in Korean children, potentially through regulatory mechanisms. These findings support the relevance of calcium channel genes in neurodevelopmental disorders and highlight the importance of integrating functional annotation in variant prioritization. Full article

Background/Objectives: This study aimed to characterize the pharmacokinetic profiles of clobazam (CLB) and its active metabolite, N-desmethylclobazam (N-CLB), by establishing a population pharmacokinetic (PPK) model in Chinese children with epilepsy to propose individualized dosing regimens that achieve better clinical outcomes. Methods: This study examined plasma samples collected from 103 pediatric patients with refractory epilepsy undergoing CLB treatment. The plasma concentrations of CLB and its active metabolite N-CLB were measured. The developmental characteristics, CYP2C19 genotype, concomitant medications, and liver and kidney function indicators of the children with epilepsy were considered potential factors affecting the pharmacokinetic characteristics of CLB and N-CLB and analyzed using a PPK modeling approach. Results: A total of 156 samples were attained for PPK model development. The pharmacokinetic profiles of CLB and N-CLB were described using a tandem one-compartment model with first-order elimination. Body weight and CYP2C19 genotype showed statistical significance for CLB and/or N-CLB clearance. The N-CLB/CLB metabolic ratios of AUC_24h, C_min, and C_max in a steady state were as follows: normal metabolizers (NMs) < intermediated metabolizers (IMs) < poor metabolizers (PMs). The final model achieved good prediction performance and stability. Monte Carlo simulations demonstrated that the trough concentrations of CLB and N-CLB in children with epilepsy could reach satisfactory target values under varying dose regimens in CYP2C19 NMs and IMs, whereas there was a failure to achieve the desired trough concentrations of CLB and N-CLB simultaneously in CYP2C19 PMs due to the accumulation of N-CLB. Conclusions: Body weight and CYP2C19 genotype had an impact on CLB and/or N-CLB clearance in children with epilepsy. To ensure safe treatment, it is recommended to use the concentration of N-CLB as the target indicator for therapeutic drug monitoring and dose adjustments in CYP2C19 PMs. These results provide evidence for guiding the precise use of CLB. Full article

Epilepsy is one of the most common neurological disorders. Disease etiology and pathogenesis are still not well understood. Genetic mutations are associated with 70% of epilepsies, while 30% are still enigmatic. Attempting to close the knowledge gap, we performed genetic analysis of a cohort of patients from the Middle East and North Africa, both understudied and highly consanguineous populations. Whole exome sequencing (WES) was carried out on 81 patients and their family members at a tertiary center in Qatar. We found damaging mutations in half of the patients: 15 in known epilepsy genes, and 19 in contested or unknown genes. The mutations include single nucleotide polymorphisms (SNVs), frameshifts, copy number variations (CNVs), and loss of homozygosity (LOH). Fifteen of the SNVs are novel, and seventeen are homozygous, reflective of the characteristics of the cohort. In addition, we used the WES data to type HLA alleles for 13 class I and II genes. We show that DRB3*01:01:02G is negatively associated with epilepsy, in contrast to DRB4*01:01:01G, which may be a risk allele. In addition to expanding the knowledge base of genes involved in epilepsy, our findings show that genetic predisposition, inclusive of immune genes, suggests a complex etiology. Full article

Disorders of vesicular trafficking and genetic defects in autophagy play a critical role in the development of metabolic and neurometabolic diseases. These processes govern intracellular transport and lysosomal degradation, thereby maintaining cellular homeostasis. In this article, we present two siblings with a novel homozygous variant in VPS51 (Vacuolar protein sorting 51) gene (c.1511C>T; p.Thr504Met), exhibiting developmental delay, a thin corpus callosum, severe intellectual disability, epilepsy, microcephaly, hearing loss, and dysphagia. This study aimed to investigate the effects of the novel VPS51 gene variation at the RNA and protein level in fibroblasts derived from patients. A comparative proteomic analysis, which has not been previously elucidated, was performed to identify uncharacterized proteins associated with vesicular trafficking. Furthermore, the impact of disrupted pathways on mitochondria–lysosome contact sites was assessed, offering a thorough pathophysiological evaluation of GARP/EARP (Golgi Associated Retrograde Protein / Endosome Associated Retrograde Protein) complex dysfunction. An analysis of mRNA expression indicated decreased levels of the VPS51 gene, alongside modifications in the expression of autophagy-related genes (LC3B, p62, RAB7A, TBC1D15). Western blotting demonstrated a reduction in VPS51 and autophagy-related protein levels. Proteomic profiling revealed 585 differentially expressed proteins, indicating disruptions in vesicular trafficking, lysosomal function, and mitochondrial metabolism. Proteins involved in mitochondrial β-oxidation and oxidative phosphorylation exhibited downregulation, whereas pathways related to glycolysis and lipid synthesis showed upregulation. Live-cell confocal microscopy revealed a notable increase in mitochondria–lysosome contact sites in patient fibroblasts, suggesting that VPS51 protein dysfunction contributes to impaired organelle communication. The findings indicate that the novel VPS51 gene variation influences intracellular transport, autophagy, and metabolic pathways, offering new insights into its involvement in neurometabolic disorders. Full article

The most investigated ABCB1 single-nucleotide polymorphisms (SNPs) related to antiseizure medication resistance are rs1045642 (c.3435C>T, p.Ile1145=), rs2032582 (c.2677G>T/A, p.Ala893Ser/Thr), and rs1128503 (c.1236C>T, p.Gly412=). We conducted a literature review to evaluate the genotype frequencies of rs1045642, rs2032582, and rs1128503 SNPs in different ancestries among the drug-resistant and drug-responsive epilepsy groups. Furthermore, we performed effect size and study power analyses and determined the expected sample size to reach a study power of 0.8 for each conducted research. High and very high statistical power for the rs1045642, rs2032582, and rs1128503 polymorphisms was achieved in 58.0, 60.7, and 31.8% of the studies, respectively. The effect sizes (ES) of rs1045642, rs2032582, and rs1128503 ranged from 0.03–1.04, 0.06–0.92, and 0.04–0.64, respectively. The required sample sizes for rs1045642, rs2032582, and rs1128503 ranged from 9–13,000, 12–2600, and 24–5700 participants, respectively. None of the polymorphisms showed a statistically significant association with antiseizure medication resistance in the forest plots. Our analysis provides valuable guidance for future genetic association studies in the field of drug-resistant epilepsy. Full article

A part of autosomal dominant sleep-related hypermotor epilepsy (ADSHE) is caused by mutant CHRNA4. The pathomechanisms underlying motor seizures followingly brief/sudden awakening (paroxysmal arousal) in ADSHE seizures remain to be clarified. This study determined extracellular levels of ACh and L-glutamate in the pedunculopontine nucleus (PPN) and its projection regions, including the thalamus and basal ganglia, during wakefulness, slow-wave sleep (SWS) and paroxysmal arousal of transgenic rats bearing rat S286L-mutant Chrna4 (S286L-TG), corresponding to human S284L-mutant CHRNA4, using microdialysis. The expression of connexin43 and pannexin1 in the plasma membrane of the PPN was determined using capillary immunoblotting. The expressions of connexin43 and pannexin1 in the PPN plasma membrane of S286L-TG were larger than the wild type. The extracellular L-glutamate levels in the PPN and projection regions of S286L-TG consistently increased during both wakefulness and SWS compared to the wild type. The extracellular levels of ACh and L-glutamate in the PPN and projection regions decreased accompaning SWS in the wild type. In S286L-TG, this decreasing extracellular ACh level was observed, whereas decreasing L-glutamate level was impaired. Both extracellular levels of ACh and L-glutamate in the PPN and projection regions drastically increased during paroxysmal arousal. Hemichannel inhibitors suppressed the increasing releases of ACh and L-glutamate induced by paroxysmal arousal but decreased and did not affect extracellular levels of L-glutamate and ACh during wakefulness and SWS, respectively. In particular, under hemichannels inhibition, decreasing L-glutamate release accompanying SWS was observed in S286L-TG. This study elucidated that enhanced hemichannels are predominantly involved in the dysfunction of glutamatergic transmission compared to AChergic transmission during the interictal stage in S286L-TG, whereas the hyperactivation of hemichannels contributes to the generation of paroxysmal arousal. Therefore, the hyperactivated excitatory tripartite synaptic transmission associated with hemichannels in the PPN and projection regions plays important roles in epileptogenesis/ictogenesis in S286L-TG. Full article

Background: Hippocampal sclerosis (HS) is a hallmark of mesial temporal lobe epilepsy (MTLE). However, genetic studies on MTLE patients with HS (MTLE-HS) remain limited, especially in East Asian populations. This study aimed to identify genetic variants associated with MTLE-HS and elucidate their biological relevance through integrative genomic and transcriptomic analyses. Methods: We conducted a genome-wide association study (GWAS) on 157 Korean epilepsy patients, including 52 MTLE-HS subjects and 105 non-acquired focal epilepsy individuals without HS as controls. The splicing and expression quantitative trait locus (sQTL and eQTL, respectively) effects of significant variants were analyzed using GTEx datasets. Transcriptomic data from the hippocampi of MTLE-HS subjects and an epilepsy mouse model were examined to assess TMEM14A expression. Gene correlation enrichment analysis was performed to investigate potential associations with epilepsy-related phenotypes. Results: The GWAS identified rs6924849, located downstream of TMEM14A, as significantly associated with MTLE-HS. The sQTL analysis revealed that rs6924849 induces abnormal TMEM14A splicing in hippocampal tissue. Transcriptomic analyses showed reduced TMEM14A expression in MTLE-HS hippocampi, while mice with pilocarpine-induced epilepsy exhibited a transient increase in TMEM14A expression during the acute phase post-status epilepticus. Gene correlation enrichment analyses linked TMEM14A to seizure-related phenotypes in both humans and mice. Conclusions: This study identifies rs6924849 as a novel genetic variant associated with MTLE-HS in an East Asian population. The dysfunctional splicing and altered expression of TMEM14A may contribute to the neuronal loss characteristic of HS, as TMEM14A regulates apoptosis. These findings emphasize the potential role of TMEM14A in MTLE-HS pathogenesis from genomic and transcriptomic perspectives. Full article

Background/Objectives: Hyperexcitable neuronal activity associated with seizures may disrupt brain homeostasis resulting in abnormal glucose and nutrient management and metabolism. Specialized ependymal cells known as tanycytes line the third ventricle wall bridging communication between the brain, CSF, and blood. Despite their positional importance, whether tanycytes are impacted by epilepsy is unknown. Here, known protein markers of tanycytes were assessed in the Kcna1-null mouse model of genetic epilepsy with spontaneous recurrent seizures (SRS mice). Further, whether an anti-seizure metabolic ketogenic diet (KD), previously proven effective in SRS mice, restored protein levels was determined. Methods: Known tanycyte proteins, including glucose transporter 1 (GLUT1), glial fibrillary acidic protein (GFAP), and doublecortin (DCX, to determine potential neurogenic differences) were examined throughout the anterior–posterior axis of the third ventricle using immunofluorescent histochemistry. Results: Decreased GLUT1 immunoreactivity and elevated GFAP levels were found in the SRS cohorts. The number of neurogenic DCX-expressing cells did not differ. Two weeks of KD treatment reduced GFAP to WT levels. GLUT1 remained low in KD-treated SRS mice. Conclusions: These data suggest that the expression of proteins important for the structure and function of tanycytes is altered in preclinical epilepsy and is differentially restored with KD treatment. Whether tanycytes actively participate in the pathophysiology of epilepsy or associated comorbidities is an intriguing possibility given their integral role in brain homeostasis. Full article

The use of animal models of idiopathic generalized epilepsy (IGE) is of great importance in the field of epilepsy research, with IGE affecting more than 20 million people worldwide. IGEs are characterized by a high degree of genetic heterogeneity, which makes it difficult to understand the underlying mechanisms leading to seizures. The development of animal models, whether spontaneous or resulting from genetic manipulation, has significantly contributed to our understanding of the pathological processes underlying certain IGEs, notably absence epilepsy. Research suggests that the concept of generalized epilepsy covering the whole brain should be replaced by a model in which the thalamus and its various nuclei are integrated into thalamo-cortical loops. These then assume distinct roles in the generation and generalization of seizures, which may differ across the spectrum of IGE disorders. The study of epileptogenesis is also essential: this area of research, grounded in systematic developmental neuroscience, examines the intermediate stages of neuronal activity to determine when, and how, functional development diverges between healthy and pathological states. Understanding nervous system development requires a comprehensive view of how anatomic, molecular, and genetics factors relate to neuronal activity. The emerging use of optogenetic methods and human assembloids will greatly aid our understanding of the mechanisms underlying these processes. Full article

Objective: Epilepsy, a common neurological disorder marked by recurrent seizures often starting in childhood, has a complex etiology. Advances in high-throughput sequencing now confirm that 70–80% of cases have a genetic basis. Accordingly, this study aims to evaluate the clinical relevance of genetic variations detected through epilepsy panels and whole exome sequencing (WES) in pediatric-onset epilepsy patients. Methods: For this study, we enrolled a cohort of pediatric patients involving 205 subjects with a preliminary diagnosis of epilepsy. Targeted next-generation sequencing panels for epilepsy and whole exome sequencing was performed using the NextSeq 500 platform. The results were analyzed with the QIAGEN Clinical Insight bioinformatic platform and were further confirmed and approved by the Human Genome Mutation Database and ClinVar databases. Results: In this study, an epilepsy panel was conducted in 138 patients, and whole exome sequencing was performed in 67 patients. No clinically relevant variants were identified in 29 (21.0%) patients who underwent the epilepsy panel and 27 (40.3%) patients who underwent WES. Variants were detected in 128 different genes in the epilepsy panel group and in 54 different genes in the WES group, with the frequency of these variants limited to one or two patients. Significance: In both the epilepsy panel and WES groups, variants in sodium channel proteins, specifically in the SCN1A, SCN8A, and SCN9A genes, were found to have a high frequency. Collectively, these findings suggest that sodium channel proteins may play an important role in epilepsy. Full article