Epilepsia最新文献

We studied the distribution of germline and somatic variants in epilepsy surgery patients with (suspected) malformations of cortical development (MCD) who underwent surgery between 2015 and 2020 at University Medical Center Utrecht (the Netherlands) and pooled our data with four previously published cohort studies. Tissue analysis yielded a pathogenic variant in 203 of 663 (31%) combined cases. In 126 of 379 (33%) focal cortical dysplasia (FCD) type II cases and 23 of 37 (62%) hemimegalencephaly cases, a pathogenic variant was identified, mostly involving the mTOR signaling pathway. Pathogenic variants in 10 focal epilepsy genes were found in 48 of 178 (27%) FCDI/mild MCD/mMCD with oligodendroglial hyperplasia and epilepsy cases; 36 of these (75%) were SLC35A2 variants. Six of 69 (9%) patients without a histopathological lesion had a pathogenic variant in SLC35A2 (n = 5) or DEPDC5 (n = 1). A germline variant in blood DNA was confirmed in all cases with a pathogenic variant in tissue, with a variant allele frequency (VAF) of ~50%. In seven of 114 patients (6%) with a somatic variant in tissue, mosaicism in blood was detected. More than half of pathogenic somatic variants had a VAF < 5%. Further analysis of the correlation between genetic variants and surgical outcomes will improve patient counseling and may guide postoperative treatment decisions.

Objective: Brain somatic variants in SLC35A2 were recently identified as a genetic marker for mild malformations of cortical development with oligodendroglial hyperplasia in epilepsy (MOGHE). The role of SLC35A2 in cortical development and the contributions of abnormal neurons and oligodendrocytes to seizure activity in MOGHE remain largely unexplored.

Methods: Here, we generated a novel Slc35a2 floxed allele, which we used to develop two Slc35a2 conditional knockout mouse lines targeting (1) the Emx1 dorsal telencephalic lineage (excitatory neurons and glia) and (2) the Olig2 lineage (oligodendrocytes). We examined brain structure, behavior, and seizure activity.

Results: Knockout of Slc35a2 from the Emx1 lineage, which targets both cortical neurons and oligodendrocytes, resulted in early lethality and caused abnormal cortical development, increased oligodendroglial cell density, early onset seizures, and developmental delays akin to what is observed in patients with MOGHE. By tracing neuronal development with 5-Ethynyl-2'-deoxyuridine (EdU) birthdating experiments, we found that Slc35a2 deficiency disrupts corticogenesis by delaying radial migration of neurons from the subventricular zone. To discern the contributions of oligodendrocytes to these phenotypes, we knocked out Slc35a2 from the Olig2 lineage. This recapitulated the increased oligodendroglial cell density and resulted in abnormal electroencephalographic activity, but without a clear seizure phenotype, suggesting Slc35a2 deficiency in neurons is required for epileptogenesis.

Significance: This study presents two novel Slc35a2 conditional knockout mouse models and characterizes the effects on brain development, behavior, and epileptogenesis. Together, these results demonstrate a direct causal role for SLC35A2 in MOGHE-like phenotypes, including a critical role in neuronal migration during brain development, and identify neurons as key contributors to SLC35A2-related epileptogenesis.

Objective: Recently, we developed a first artificial intelligence (AI)-based digital pathology classifier for focal cortical dysplasia (FCD) as defined by the ILAE classification. Herein, we tested the usefulness of the classifier in a retrospective histopathology workup scenario.

Methods: Eighty-six new cases with histopathologically confirmed FCD ILAE type Ia (FCDIa), FCDIIa, FCDIIb, mild malformation of cortical development with oligodendroglial hyperplasia in epilepsy (MOGHE), or mild malformations of cortical development were selected, 20 of which had confirmed gene mosaicism.

Results: The classifier always recognized the correct histopathology diagnosis in four or more 1000 × 1000-μm digital tiles in all cases. Furthermore, the final diagnosis overlapped with the largest batch of tiles assigned by the algorithm to one diagnostic entity in 80.2% of all cases. However, 86.2% of all cases revealed more than one diagnostic category. As an example, FCDIIb was identified in all of the 23 patients with histopathologically assigned FCDIIb, whereas the classifier correctly recognized FCDIIa tiles in 19 of these cases (83%), that is, dysmorphic neurons but no balloon cells. In contrast, the classifier misdiagnosed FCDIIb tiles in seven of 23 cases histopathologically assigned to FCDIIa (33%). This mandates a second look by the signing histopathologist to either confirm balloon cells or differentiate from reactive astrocytes. The algorithm also recognized coexisting architectural dysplasia, for example, vertically oriented microcolumns as in FCDIa, in 22% of cases classified as FCDII and in 62% of cases with MOGHE. Microscopic review confirmed microcolumns in the majority of tiles, suggesting that vertically oriented architectural abnormalities are more common than previously anticipated.

Significance: An AI-based diagnostic classifier will become a helpful tool in our future histopathology laboratory, in particular when large anatomical resections from epilepsy surgery require extensive resources. We also provide an open access web application allowing the histopathologist to virtually review digital tiles obtained from epilepsy surgery to corroborate their final diagnosis.

Objective: Determining the pathogenicity of missense variants in clinical genetic tests for individuals with epilepsy is crucial for guiding personalized treatment. However, achieving a definitive pathogenic classification remains challenging, with most missense variants still classified as variants of uncertain significance (VUS) and with the availability of many computational tools which may provide conflicting predictions. Here, we aim to evaluate the performance of state-of-the-art computational tools in pathogenicity prediction of missense variants in epilepsy-associated genes. This will assist in selecting the most appropriate tool and critically assess their use in clinical setting.

Methods: We assessed the performance of nine in silico pathogenicity prediction tools for missense variants in epilepsy-associated genes on three carefully curated data sets. The first two data sets comprise missense variants in epilepsy associated genes that have been uploaded to ClinVar in the last year and were, therefore, not part of the training set of any of the nine considered tools. These two data sets are based on two different lists of epilepsy-associated genes and comprise ~700 and ~ 250 missense variants, respectively. The third data set includes ~400 missense variants within epilepsy-associated genes for which the functional effects have been determined experimentally and are therefore used here to infer pathogenicity. These three data sets represent the best available approximation to blind and independent test sets.

Results: Among the nine assessed tools, AlphaMissense (area under the curve [AUC]: .93, .88, and .95) and REVEL (AUC: .93, .88, and .93) showed the best classification performance, also outperforming other tools in the number of classified variants.

Significance: We show which recently developed prediction tools achieve higher performance in epilepsy-associated genes and should be integrated, therefore, into the American College of Medical Genetics and Genomics/Association of Molecular Pathology (AGMC/AMP) variant classification process. Periodic reevaluation of genetic test results with newly developed or updated tools should be incorporated into standard clinical practice to improve diagnostic yield and better inform precision medicine.

Individuals with epilepsy are at risk of developing preictal, ictal, postictal and interictal psychoses. Antipsychotic drugs (APDs) are the main class of drugs used to treat psychosis and schizophrenia. The efficacy and safety of APDs as a treatment for epileptic psychosis is not well understood. This systematic review aimed to assess the effectiveness and adverse effects of APDs for treating psychosis in people with epilepsy. We adhered to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. We searched MEDLINE, Embase, PsycInfo, and AMED (Allied and Complementary Medicine) from database inception to June 20, 2023. We contacted experts in the field and performed citation searches to identify additional records. Title, abstract, full-text review, and data analysis were conducted in duplicate, with conflicts resolved by discussion among authors. Given the considerable heterogeneity of study designs, meta-analysis was not deemed appropriate; instead, the results were tabulated in a narrative synthesis. The Joanna Briggs Institute Risk of Bias tool and GRADE (Grading of Recommendations Assessment, Development, and Evaluation) framework were used to assess study quality. We identified 13 studies with a total of 1180 participants. In the four case series included, the psychotic symptoms of 25 of 28 patients treated with APDs partially improved or fully resolved. Three of the four cohort studies reported an association between antipsychotic use and longer duration of psychotic episodes, two found similar results in both APD and non-APD groups, and two did not report control psychosis outcomes. When reported, seizure frequency was observed to remain unchanged or decrease following APD treatment. The evidence on the effectiveness of antipsychotics in the treatment of psychosis in epilepsy is inconclusive and may reflect confounding by indication. However, most studies suggest that antipsychotics were not associated with a marked worsening in seizure frequency. It remains unclear whether antipsychotics should be used in epilepsy, and well-controlled cohort studies and randomized controlled trials are necessary to draw definitive conclusions.

Objective: Deep brain stimulation, particularly low-frequency stimulation (LFS) targeting fiber tracts, has emerged as a potential therapy for drug-resistant epilepsy (DRE) and for generalized epilepsy, both of which pose significant treatment challenges. LFS diffusely suppresses seizures in the cortex when applied to fiber tracts like the corpus callosum (CC). Nevertheless, the specific processes responsible for suppressing epileptic activity in the cortex induced by LFS remain unclear. This study investigates the mechanisms underlying the antiepileptic effect in the cortex of LFS of the CC in coronal rodent brain slices.

Methods: An in vitro 4-aminopyridine (4-AP) seizure model of cortical seizures was generated. LFS stimulation parameters were optimized to provide the largest antiepileptic effect in the cortex when applied to the CC. Changes to tissue excitability and percent time spent seizing were measured due to LFS in artificial cerebrospinal fluid, 4-AP, and in the presence of various specific and nonspecific γ-aminobutyric acid type B (GABA_B) and slow afterhyperpolarization (sAHP) antagonists.

Results: LFS significantly suppressed seizure activity in the cortex, with an optimal frequency of 5 Hz (76.5%). Tissue excitability during LFS reduces across a wide range of interstimulus intervals, with a maximum reduction at 200 ms. Notably, the tissue excitability remains depressed at 1000 ms. LFS, in the presence of GABA_B antagonists, had diminished seizure reduction (<15%) and failed to reduce tissue excitability in the 50-400-ms range. Tissue excitability measured with paired pulses in the 600-1000-ms range was depressed in the presence of GABA_B antagonists, suggesting a different antiepileptic mechanism was active. Upon administering sAHP antagonists, seizure reduction was once again diminished (<15%). Upon administration of both sAHP and GABA_B antagonists, LFS failed to provide any meaningful seizure reduction (<5%).

Significance: LFS of the CC provides an antiepileptic effect in the cortex with well-understood mechanisms and could be an alternative to surgical intervention for patients suffering from DRE.

Time is critical in executing acute seizure treatment, and efforts to minimize operational delays with medication preparation confer potential logistical and practical advantages. Multiple studies have demonstrated the safety and tolerability of intravenous (IV) undiluted levetiracetam (LEV) in adults; however, published pediatric data are limited. This study aims to evaluate the safety and tolerability of IV undiluted LEV in pediatrics. This was a retrospective, dual-center, observational cohort study evaluating concentration-related adverse drug events with IV undiluted (100 mg/mL) LEV in pediatrics over a 3-year 3-month timespan. A total of 60 undiluted administrations in 52 patients were included in the study. The median age was 4 years; 58.3% of patients were younger than 5 years of age. All doses were administered via a peripheral IV line. The most common IV anatomic site and peripheral IV gauge (G) was the antecubital (66.6%) and 22G catheter (63.3%). There were no documented concentration-related adverse drug events. Regardless of IV anatomic site, IV gauge, and administered dose there were no documented concentration-related adverse effects with IV undiluted LEV in a pediatric population. IV undiluted LEV may be considered safe and tolerable in pediatrics. Prospective pediatric studies should assess the safety and tolerability of IV undiluted LEV.