Leu, Costin

Abstract Epilepsy affects more than 50 million individuals globally and has a substantial genetic component that remains to be completely understood. Traditional studies have focused on severe, early onset cases enrolled through clinical or research settings. Recent biobank‐based approaches, leveraging large‐scale population datasets, offer opportunities to explore genetic associations in broader epilepsy phenotypes, including milder, later onset forms. We analyzed data from more than 750 000 individuals across the UK Biobank, All of Us, and Massachusetts General Brigham Biobank, including 20 026 individuals with epilepsy. Rare coding variant burden testing revealed a significant association with LGI1 , a known epilepsy gene. Among the other top 10 associated genes, seven had prior evidence linking them to epilepsy ( GABRG2 , ATP1A3 ), neurological disorders with comorbid seizures ( HTRA2 , KRIT1 , STAG1 ), possible involvement in seizure phenotypes ( ADAM23 ), or roles in neuronal function ( PDCD4 ). Thus, we provide the first statistical evidence for ADAM23 as a candidate gene for epilepsy, based on the suggestive association signal combined with prior biological evidence from both animal (canine and murine) and one recent human epilepsy case study, potentially contributing to human epilepsy through its direct interaction with LGI1 . Phenome‐wide analyses highlighted the pleiotropic effects of epilepsy genes, with LGI1 and ADAM23 predominantly associated with epilepsy, whereas other genes such as KRIT1 , TSC1 , and TSC2 exhibited broader systemic involvement. Our study shows the potential of population‐scale genomic data and suggests that integrating these datasets with deep phenotyping will uncover more novel insights into epilepsy genetics in the future.

Abstract Rationale Neurodevelopmental disorders (NDDs) are characterised by significant challenges in communication, social interaction, and adaptive function, often impacting quality of life. Previous studies support genetic influences on the communication abilities of individuals with NDD, but were either limited to single genetic conditions or to small cohorts with a limited selection of communication measures. Methods We analysed caregiver-reported communication abilities in 79,518 individuals with NDD from the Simons Searchlight and SPARK registries: 4,439 with a CNV-based or monogenic NDD and 75,079 with autism spectrum disorder (ASD) without a known genetic cause (idiopathic ASD) as controls. For analysis, we a priori selected 10 communication-related measures based on their availability in the study cohorts, coverage of distinct communication aspects, and their frequent use in neurodevelopmental phenotyping, yielding 177,328 data points across all study cohorts. The individuals in the Searchlight registry were divided into a Discovery cohort (the 15 most prevalent genetic NDD conditions) and a Confirmation cohort (all other genetic NDD conditions). A second Confirmation cohort was generated using all individuals with genetic ASD forms from the SPARK registry. We then tested each of the three case cohorts and each genetic condition represented in the Discovery cohort against the ASD control cohort. Developmental trajectories were assessed through testing of participants grouped by age at evaluation. Results Measure-level analyses demonstrated significant associations between genetic status and communication abilities, differences in communication abilities between classes of genetic variants (monogenic vs. CNV-based NDDs), and variability between specific genetic NDD conditions. CNV-based NDDs showed milder communication impairment, outperforming idiopathic ASD controls in 9/10 communication measures, whereas monogenic NDD conditions had more pervasive impairments, especially in verbal communication. Although impaired in verbal communication, five monogenic NDD conditions showed at least suggestive strengths in nonverbal and social communication relative to idiopathic ASD controls ( CSNK2A1 , CTNNB1 , SETBP1 , MED13L , and PPP2R5D ), specifically in using gestures. Developmental trajectory analyses revealed STXBP1 as the gene group at highest risk of developmental stagnation in communication abilities. Conclusions These findings underscore the potential of precision speech-language pathology (SLP) approaches tailored to the specific verbal and nonverbal communication strengths and weaknesses of genetic groups. We also provide evidence for measurable improvements and declines in communication abilities with age at the group level, highlighting the need for developmentally informed care. By integrating genetic insights into clinical practice, precision SLP approaches may enhance communication outcomes and developmental progress and improve quality of life for individuals with genetic NDDs.

Abstract Aim To assess the long‐term efficacy of vagus nerve stimulation (VNS) in Dravet syndrome and identify key factors influencing treatment response. Method We conducted a two‐center, retrospective cohort study of 15 patients (six females, nine males; median age at seizure onset 4 months [range 2–12 months]) with Dravet syndrome who underwent VNS implantation. Seizure frequency was evaluated over 12 months and up to 10 years after implantation. Linear mixed‐effects regression was used to analyze the impact of antiseizure medications (ASMs) and VNS parameters on seizure outcomes. Results A 50% or greater reduction in seizure frequency was observed in 93.3% (14 of 15) of patients at 12 months and 86.7% (13 of 15) of patients across the 10‐year follow‐up. This seizure reduction was independent of ASM use; the VNS duty cycle was a significant predictor of seizure reduction. Two individuals (13.3%) experienced minor adverse events. Interpretation VNS provides durable seizure reduction in Dravet syndrome, independent of ASM adjustments. These findings highlight the importance of early VNS initiation and parameter optimization in managing genetically defined epilepsy syndromes.

Abstract Aims The causes of distinct patterns of reduced cortical thickness in the common human epilepsies, detectable on neuroimaging and with important clinical consequences, are unknown. We investigated the underlying mechanisms of cortical thinning using a systems‐level analysis. Methods Imaging‐based cortical structural maps from a large‐scale epilepsy neuroimaging study were overlaid with highly spatially resolved human brain gene expression data from the Allen Human Brain Atlas. Cell‐type deconvolution, differential expression analysis and cell‐type enrichment analyses were used to identify differences in cell‐type distribution. These differences were followed up in post‐mortem brain tissue from humans with epilepsy using Iba1 immunolabelling. Furthermore, to investigate a causal effect in cortical thinning, cell‐type‐specific depletion was used in a murine model of acquired epilepsy. Results We identified elevated fractions of microglia and endothelial cells in regions of reduced cortical thickness. Differentially expressed genes showed enrichment for microglial markers and, in particular, activated microglial states. Analysis of post‐mortem brain tissue from humans with epilepsy confirmed excess activated microglia. In the murine model, transient depletion of activated microglia during the early phase of the disease development prevented cortical thinning and neuronal cell loss in the temporal cortex. Although the development of chronic seizures was unaffected, the epileptic mice with early depletion of activated microglia did not develop deficits in a non‐spatial memory test seen in epileptic mice not depleted of microglia. Conclusions These convergent data strongly implicate activated microglia in cortical thinning, representing a new dimension for concern and disease modification in the epilepsies, potentially distinct from seizure control.