GWAS meta-analysis of over 29,000 people with epilepsy identifies 26 risk loci and subtype-specific genetic architecture

Epilepsy is a highly heritable disorder affecting over 50 million people worldwide, of which about one-third are resistant to current treatments. Here we report a multi-ancestry genome-wide association study including 29,944 cases, stratified into three broad categories and seven subtypes of epilepsy, and 52,538 controls. We identify 26 genome-wide significant loci, 19 of which are specific to genetic generalized epilepsy (GGE). We implicate 29 likely causal genes underlying these 26 loci. SNP-based heritability analyses show that common variants explain between 39.6% and 90% of genetic risk for GGE and its subtypes. Subtype analysis revealed markedly different genetic architectures between focal and generalized epilepsies. Gene-set analyses of GGE signals implicate synaptic processes in both excitatory and inhibitory neurons in the brain. Prioritized candidate genes overlap with monogenic epilepsy genes and with targets of current antiseizure medications. Finally, we leverage our results to identify alternate drugs with predicted efficacy if repurposed for epilepsy treatment

Diffusion magnetic resonance imaging connectome featuresare predictive of functional lateralization of semanticprocessing in the anterior temporal lobes

Assessment of regional language lateralization is crucial in many scenarios, but not allpopulations are suited for its evaluation via task-functional magnetic resonance imag-ing (fMRI). In this study, the utility of structural connectome features for the classifi-cation of language lateralization in the anterior temporal lobes (ATLs) wasinvestigated. Laterality indices for semantic processing in the ATL were computedfrom task-fMRI in 1038 subjects from the Human Connectome Project who werelabeled as stronger rightward lateralized (RL) or stronger leftward to bilaterally latera-lized (LL) in a data-driven approach. Data of unrelated subjects (n=432) were usedfor further analyses. Structural connectomes were generated from diffusion-MRItractography, and graph theoretical metrics (node degree, betweenness centrality)were computed. A neural network (NN) and a random forest (RF) classifier weretrained on these metrics to classify subjects as RL or LL. After classification, compari-sons of network measures were conducted via permutation testing. Degree-basedclassifiers produced significant above-chance predictions both during cross-validation(NN: AUC–ROC[CI]=0.68[0.64–0.73], accuracy[CI]=68.34%[63–73.2%]; RF:AUC–ROC[CI]=0.7[0.66–0.73], accuracy[CI]=64.81%[60.9–68.5]) and testing(NN: AUC–ROC[CI]=0.69[0.53–0.84], accuracy[CI]=68.09[53.2–80.9]; RF: AUC–ROC[CI]=0.68[0.53–0.84], accuracy[CI]=68.09[55.3–80.9]). Comparison of net-work metrics revealed small effects of increased node degree within the right poste-rior middle temporal gyrus (pMTG) in subjects with RL, while degree was decreasedin the right posterior cingulate cortex (PCC). Above-chance predictions of functionallanguage lateralization in the ATL are possible based on diffusion-MRI connectomesalone. Increased degree within the right pMTG as a right-sided homologue of aknown semantic hub, and decreased hubness of the right PCC may form a structuralbasis for rightward-lateralized semantic processing

Brivaracetam in the Treatment of Patients with Epilepsy—First Clinical Experiences

ObjectivesTo assess first clinical experiences with brivaracetam (BRV) in the treatment of epilepsies.MethodsData on patients treated with BRV from February to December 2016 and with at least one clinical follow-up were collected from electronic patient records. Data on safety and efficacy were evaluated retrospectively.ResultsIn total, 93 patients were analyzed; 12 (12.9%) received BRV in monotherapy. The mean duration to follow-up was 4.85 months (MD = 4 months; SD = 3.63). Fifty-seven patients had more than one seizure per month at baseline and had a follow-up of more than 4 weeks; the rate of ≥50% responders was 35.1% (n = 20) in this group, of which five (8.8%) patients were newly seizure-free. In 50.5% (47/93), patients were switched from levetiracetam (LEV) to BRV, of which 43 (46.2%) were switched immediately. Adverse events (AE) occurred in 39.8%, with 22.6% experiencing behavioral and 25.8% experiencing non-behavioral AE. LEV-related AE (LEV-AE) were significantly reduced by switching to BRV. The discontinuation of BRV was reported in 26/93 patients (28%); 10 of those were switched back to LEV with an observed reduction of AE in 70%. For clinical reasons, 12 patients received BRV in monotherapy, 75% were seizure–free, and previous LEV-AE improved in 6/9 patients. BRV-related AE occurred in 5/12 cases, and five patients discontinued BRV.ConclusionBRV seems to be a safe, easy, and effective option in the treatment of patients with epilepsy, especially in the treatment of patients who have psychiatric comorbidities and might not be good candidates for LEV treatment. BRV broadens the therapeutic spectrum and facilitates personalized treatment

Spectrum of Phenotypic, Genetic, and Functional Characteristics in Patients With Epilepsy With KCNC2 Pathogenic Variants

Background and Objectives KCNC2 encodes Kv3.2, a member of the Shaw-related (Kv3) voltage-gated potassium channel subfamily, which is important for sustained high-frequency firing and optimized energy efficiency of action potentials in the brain. The objective of this study was to analyze the clinical phenotype, genetic background, and biophysical function of disease-associated Kv3.2 variants. Methods Individuals with KCNC2 variants detected by exome sequencing were selected for clinical, further genetic, and functional analysis. Cases were referred through clinical and research collaborations. Selected de novo variants were examined electrophysiologically in Xenopus laevis oocytes. Results We identified novel KCNC2 variants in 18 patients with various forms of epilepsy, including genetic generalized epilepsy (GGE), developmental and epileptic encephalopathy (DEE) including early-onset absence epilepsy, focal epilepsy, and myoclonic-atonic epilepsy. Of the 18 variants, 10 were de novo and 8 were classified as modifying variants. Eight drug-responsive patients became seizure-free using valproic acid as monotherapy or in combination, including severe DEE cases. Functional analysis of 4 variants demonstrated gain of function in 3 severely affected DEE cases and loss of function in 1 case with a milder phenotype (GGE) as the underlying pathomechanisms. Discussion These findings implicate KCNC2 as a novel causative gene for epilepsy and emphasize the critical role of K(V)3.2 in the regulation of brain excitability

Heterozygous variants in KCNC2 cause a broad spectrum of epilepsy phenotypes associated with characteristic functional alterations 2021.05.21.21257099

Background KCNC2 encodes a member of the shaw-related voltage-gated potassium channel family (KV3.2), which are important for sustained high-frequency firing and optimized energy efficiency of action potentials in the brain.Methods Individuals with KCNC2 variants detected by exome sequencing were selected for clinical, further genetic and functional analysis. The cases were referred through clinical and research collaborations in our study. Four de novo variants were examined electrophysiologically in Xenopus laevis oocytes.Results We identified novel KCNC2 variants in 27 patients with various forms of epilepsy. Functional analysis demonstrated gain-of-function in severe and loss-of-function in milder phenotypes as the underlying pathomechanisms with specific response to valproic acid.Conclusion These findings implicate KCNC2 as a novel causative gene for epilepsy emphasizing the critical role of KV3.2 in the regulation of brain excitability with an interesting genotype-phenotype correlation and a potential concept for precision medicine

Spectrum of Phenotypic, Genetic, and Functional Characteristics in Epilepsy Patients With KCNC2 Pathogenic Variants 10.1212/WNL.0000000000200660

Background: KCNC2 encodes Kv3.2, a member of the Shaw-related (Kv3) voltage-gated potassium channel subfamily, which is important for sustained high-frequency firing and optimized energy efficiency of action potentials in the brain. The objective of this study was to analyse the clinical phenotype, genetic background, and biophysical function of disease-associated Kv3.2 variants.Methods: Individuals with KCNC2 variants detected by exome sequencing were selected for clinical, further genetic, and functional analysis. Cases were referred through clinical and research collaborations. Selected de novo variants were examined electrophysiologically in Xenopus laevis oocytes.Results: We identified novel KCNC2 variants in 18 patients with various forms of epilepsy including genetic generalized epilepsy (GGE), developmental and epileptic encephalopathy (DEE) including early-onset absence epilepsy (EOAE), focal epilepsy (FE), and myoclonic-atonic epilepsy (MAE). 10/18 variants were de novo and 8/18 variants were classified as modifying variants. 8 drug responsive cases became seizure-free using valproic acid as monotherapy or in combination including severe DEE cases. Functional analysis of four variants demonstrated gain-of-function in three severely affected DEE cases and loss-of-function in one case with a milder phenotype (GGE) as the underlying pathomechanisms.Conclusion: These findings implicate KCNC2 as a novel causative gene for epilepsy and emphasize the critical role of KV3.2 in the regulation of brain excitability

Spectrum of Phenotypic, Genetic, and Functional Characteristics in Epilepsy Patients With KCNC2 Pathogenic Variants

Background: KCNC2 encodes Kv3.2, a member of the Shaw-related (Kv3) voltage-gated potassium channel subfamily, which is important for sustained high-frequency firing and optimized energy efficiency of action potentials in the brain. The objective of this study was to analyse the clinical phenotype, genetic background, and biophysical function of disease-associated Kv3.2 variants. Methods: Individuals with KCNC2 variants detected by exome sequencing were selected for clinical, further genetic, and functional analysis. Cases were referred through clinical and research collaborations. Selected de novo variants were examined electrophysiologically in Xenopus laevis oocytes. Results: We identified novel KCNC2 variants in 18 patients with various forms of epilepsy including genetic generalized epilepsy (GGE), developmental and epileptic encephalopathy (DEE) including early-onset absence epilepsy (EOAE), focal epilepsy (FE), and myoclonic-atonic epilepsy (MAE). 10/18 variants were de novo and 8/18 variants were classified as modifying variants. 8 drug responsive cases became seizure-free using valproic acid as monotherapy or in combination including severe DEE cases. Functional analysis of four variants demonstrated gain-of-function in three severely affected DEE cases and loss-of-function in one case with a milder phenotype (GGE) as the underlying pathomechanisms. Conclusion: These findings implicate KCNC2 as a novel causative gene for epilepsy and emphasize the critical role of KV3.2 in the regulation of brain excitability