Gene therapy for Lafora disease in the Epm2a-/- mouse model.

Lafora disease is a rare and fatal form of progressive myoclonic epilepsy typically occurring early in adolescence. The disease results from mutations in the EPM2A gene, encoding laforin, or the EPM2B gene, encoding malin. Laforin and malin work together in a complex to control glycogen synthesis and prevent the toxicity produced by misfolded proteins via the ubiquitin-proteasome system. Disruptions in either protein cause alterations in this complex, leading to the formation of Lafora bodies containing abnormal, insoluble, and hyperphosphorylated forms of glycogen. We used the Epm2a-/- knockout mouse model of Lafora disease to apply gene therapy by administering intracerebroventricular injections of a recombinant adeno-associated virus carrying the human EPM2A gene. We evaluated the effects of this treatment through neuropathological studies, behavioral tests, video-electroencephalography, electrophysiological recordings, and proteomic/phosphoproteomic analysis. Gene therapy ameliorated neurological and histopathological alterations, reduced epileptic activity and neuronal hyperexcitability, and decreased the formation of Lafora bodies. Moreover, differential quantitative proteomics and phosphoproteomics revealed beneficial changes in various molecular pathways altered in Lafora disease. Our results represent proof of principle for gene therapy with the coding region of the human EPM2A gene as a treatment for EPM2A-related Lafora disease.

Epm2aR240X knock-in mice present earlier cognitive decline and more epileptic activity than Epm2a-/- mice.

Lafora disease is a rare recessive form of progressive myoclonic epilepsy, usually diagnosed during adolescence. Patients present with myoclonus, neurological deterioration, and generalized tonic-clonic, myoclonic, or absence seizures. Symptoms worsen until death, usually within the first ten years of clinical onset. The primary histopathological hallmark is the formation of aberrant polyglucosan aggregates called Lafora bodies in the brain and other tissues. Lafora disease is caused by mutations in either the EPM2A gene, encoding laforin, or the EPM2B gene, coding for malin. The most frequent EPM2A mutation is R241X, which is also the most prevalent in Spain. The Epm2a-/- and Epm2b-/- mouse models of Lafora disease show neuropathological and behavioral abnormalities similar to those seen in patients, although with a milder phenotype. To obtain a more accurate animal model, we generated the Epm2aR240X knock-in mouse line with the R240X mutation in the Epm2a gene, using genetic engineering based on CRISPR-Cas9 technology. Epm2aR240X mice exhibit most of the alterations reported in patients, including the presence of LBs, neurodegeneration, neuroinflammation, interictal spikes, neuronal hyperexcitability, and cognitive decline, despite the absence of motor impairments. The Epm2aR240X knock-in mouse displays some symptoms that are more severe that those observed in the Epm2a-/- knock-out, including earlier and more pronounced memory loss, increased levels of neuroinflammation, more interictal spikes and increased neuronal hyperexcitability, symptoms that more precisely resemble those observed in patients. This new mouse model can therefore be specifically used to evaluate how new therapies affects these features with greater precision.

Familial adult myoclonus epilepsy: Clinical findings, disease course, and comorbidities.

Familial adult myoclonus epilepsy (FAME) is an autosomal dominant condition characterized by the association of myoclonic tremor and epilepsy mainly with onset in adulthood. The clinical course is non-progressive or slowly progressive, as epilepsy is commonly controlled with appropriate antiseizure medication and individuals have a normal life expectancy. However, the myoclonus severity increases with age and leads to some degree of disability in the elderly. Because the non-coding repeat expansions responsible for FAME are not detected by routine genetic tests being used at this time, a clinical diagnosis accompanied by neurophysiological testing remains essential to guide the geneticist on the selection of the specific genetic technique.

Number needed to treat and associated cost analysis of cenobamate versus third-generation anti-seizure medications for the treatment of focal-onset seizures in patients with drug-resistant epilepsy in Spain.

INTRODUCTION: Epilepsy is a serious neurological disease, ranking high in the top causes of disability. The main goal of its treatment is to achieve seizure freedom without intolerable adverse effects. However, approximately 40% of patients suffer from Drug-Resistant Epilepsy (DRE) despite the availability of the latest options called third-generation Anti-Seizure Medications(ASMs). Cenobamate is the first ASM approved in Spain for the adjunctive treatment of Focal-Onset Seizures (FOS) in adult patients with DRE. The introduction of a new drug increases the number of therapeutic options available, making it important to compare it with existing alternatives in terms of clinical benefit and efficiency. PURPOSE: This study aimed to compare the clinical benefit, in terms of the Number Needed to Treat (NNT), and the efficiency, in terms of Cost per NNT (CNT), associated with cenobamate versus third-generation ASMs used in Spain for the adjunctive treatment of FOS in patients with DRE. METHODS: The Number Needed to Treat data was calculated based on the ≥50% responder rate and seizure freedom endpoints (defined as the percentage of patients achieving 50% and 100% reduction in seizure frequency, respectively), obtained from pivotal clinical trials performed with cenobamate, brivaracetam, perampanel, lacosamide, and eslicarbazepine acetate. The NNT was established as the inverse of the treatment responder rate minus the placebo responder rate and was calculated based on the minimum, mid-range Daily Defined Dose (DDD), and maximum doses studied in the pivotal clinical trials of each ASM. CNT was calculated by multiplying the annual treatment cost by NNT values for each treatment option. RESULTS: In terms of NNT, cenobamate was the ASM associated with the lowest values at all doses for both ≥50% responder rate and seizure freedom compared with the alternatives. In terms of CNT, for ≥50% responder rate, cenobamate was the ASM associated with the lowest CNT values at DDD and lacosamide and eslicarbazepine acetate at the minimum and maximum dose, respectively. For seizure freedom, cenobamate was associated with the lowest CNT value at DDD and the maximum dose and lacosamide at the minimum dose. CONCLUSIONS: Cenobamate could represent the most effective ASM in all doses studied compared to the third-generation ASMs and the most efficient option at DDD for both ≥50% responder rate and seizure freedom. This study could represent an important contribution towards informed decision-making regarding the selection of the most appropriate therapy for FOS in adult patients with DRE from a clinical and economical perspective in Spain.

Initial monotherapy with eslicarbazepine acetate for the management of adult patients with focal epilepsy in clinical practice: a meta-analysis of observational studies.

AIM OF THE STUDY: To assess the effectiveness, overall tolerability of eslicarbazepine acetate (ESL) as an initial or early monotherapy treatment of adult patients with focal epilepsy under real-world practice conditions. MATERIALS AND METHODS: We focused on real-world longitudinal studies that included or separately reported the results of at least one of the efficacy outcomes of interest. A DerSimonian-Laird random effects model was used with the presentation of the 95% confidence intervals of the estimate. RESULTS: 5 studies met our selection criteria and were included in the quantitative synthesis. All studies were observational and uncontrolled studies, and all but one were retrospective studies. The pooled proportion of patients who were seizure-free for the entire study period was 64.6% (95% CI, 45.7 to 79.8) at month 6 and 56.6% (95% CI, 50.2 to 62.8) at month 12. Pooled retention rates were 95.0% (95% CI, 90.3 to 97.5) at 6 months and 83.6% (95% CI, 73.9 to 90.1) at 12 months. The pooled proportion of patients who reported at least one adverse event was 27.2% (95% CI, 21.7 to 33.6), and the pooled proportion of patients who discontinued ESL due to adverse events was 8.9% (95% CI 6.2 to 12.6). CONCLUSIONS: Our results suggest that initial or early monotherapy with ESL is effective and well-tolerated for the management of adult patients with focal epilepsy in clinical practice, with results that are at least similar to those reported in the pivotal randomized clinical trial of ESL monotherapy. No new safety signals with ESL have been identified in this systematic review.

Onset of efficacy and adverse events during Cenobamate titration period.

OBJECTIVES: Cenobamate is an antiseizure medication (ASM) approved in Europe as adjunctive therapy for adults with inadequately controlled focal seizures. This post hoc analysis reports onset of efficacy and characterizes time to onset, duration, and severity of the most common treatment-emergent adverse events (TEAEs) during cenobamate titration. MATERIALS & METHODS: Adult patients with uncontrolled focal seizures taking 1 to 3 concomitant ASMs were randomized to receive adjunctive cenobamate or placebo (double-blind studies C013 and C017) or cenobamate (open-label study C021). Outcome assessments included efficacy (median percentage change in seizure frequency and onset [studies C013 and C017]) and safety (onset, duration, and severity of TEAEs [all studies]). RESULTS: Onset of efficacy was observed by Weeks 1 to 4 of titration in studies C013 and C017 which used a faster titration schedule than study CO21. In study C013, the median percentage seizure frequency reduction was 36.7% in patients receiving cenobamate versus 16.3% in those taking placebo (p = .002); in study C017, significant differences in seizure frequency emerged in Week 1 and continued throughout titration between all cenobamate groups and placebo (p < .001). The most commonly reported TEAEs were somnolence, dizziness, fatigue, and headache, with first onset of each reported as early as Week 1; however, the majority resolved. CONCLUSIONS: Reductions in seizure frequency occurred during titration with initial efficacy observed prior to reaching the target dose. These reductions were regarded as clinically meaningful because they may indicate early efficacy at lower doses than previously expected and had a considerable impact on patient quality of life. Long-term treatment with adjunctive cenobamate was generally safe and well-tolerated.

Variant Intestinal-Cell Kinase in Juvenile Myoclonic Epilepsy.

BACKGROUND: In juvenile myoclonic epilepsy, data are limited on the genetic basis of networks promoting convulsions with diffuse polyspikes on electroencephalography (EEG) and the subtle microscopic brain dysplasia called microdysgenesis. METHODS: Using Sanger sequencing, we sequenced the exomes of six members of a large family affected with juvenile myoclonic epilepsy and confirmed cosegregation in all 37 family members. We screened an additional 310 patients with this disorder for variants on DNA melting-curve analysis and targeted real-time DNA sequencing of the gene encoding intestinal-cell kinase ( ICK). We calculated Bayesian logarithm of the odds (LOD) scores for cosegregating variants, odds ratios in case-control associations, and allele frequencies in the Genome Aggregation Database. We performed functional tests of the effects of variants on mitosis, apoptosis, and radial neuroblast migration in vitro and conducted video-EEG studies in mice lacking a copy of Ick. RESULTS: A variant, K305T (c.914A→C), cosegregated with epilepsy or polyspikes on EEG in 12 members of the family affected with juvenile myoclonic epilepsy. We identified 21 pathogenic ICK variants in 22 of 310 additional patients (7%). Four strongly linked variants (K220E, K305T, A615T, and R632X) impaired mitosis, cell-cycle exit, and radial neuroblast migration while promoting apoptosis. Tonic-clonic convulsions and polyspikes on EEG resembling seizures in human juvenile myoclonic epilepsy occurred more often in knockout heterozygous mice than in wild-type mice (P=0.02) during light sleep with isoflurane anesthesia. CONCLUSIONS: Our data provide evidence that heterozygous variants in ICK caused juvenile myoclonic epilepsy in 7% of the patients included in our analysis. Variant ICK affects cell processes that help explain microdysgenesis and polyspike networks observed on EEG in juvenile myoclonic epilepsy. (Funded by the National Institutes of Health and others.).

Practical guidance for the management of adults receiving adjunctive cenobamate for the treatment of focal epilepsy-expert opinion.

Clinical trial results have demonstrated that adjunctive cenobamate (CNB) substantially decreases seizure frequency in adults with uncontrolled focal onset seizures with an acceptable and well-identified safety profile. This manuscript summarizes an expert panel's recommendations regarding optimized CNB treatment of epilepsies with focal onset seizures. Cenobamate, when slowly titrated to the target maintenance dose, represents an effective new antiseizure medication (ASM) with a comparatively high rate of seizure freedom relative to existing treatment options. This paper reviews selection of suitable CNB treatment candidates, realistic treatment expectations and goals, appropriate CNB target doses, and methods to mitigate or avoid potential adverse events. Cenobamate can be a promising therapeutic choice for adult people with epilepsy with focal onset seizures who do not reach adequate seizure control despite treatment with conventional ASMs.

Identifying key unmet needs and value drivers in the treatment of focal-onset seizures (FOS) in patients with drug-resistant epilepsy (DRE) in Spain through Multi-Criteria Decision Analysis (MCDA).

INTRODUCTION: Epilepsy is a serious neurological disease, ranking high in the top causes of disability. Approximately 40% of patients with epilepsy are pharmacoresistant after their seizures failed at least two antiseizure medications (ASMs). Adult patients experiencing focal-onset seizures (FOS) account for approximately 60% of all patients with epilepsy and they are more likely to become drug-resistant epilepsy (DRE) than those with generalized onset. Drug-resistant epilepsy is associated with mortality, morbidity, and reduced quality of life. The information available on the clinical management, health outcomes, and unmet needs of the disease within the Spanish healthcare environment is very limited. Multi-Criteria Decision Analysis (MCDA) allows determination of what represents value in a given indication considering all relevant criteria for healthcare decision-making in a transparent and systematic manner and from the perspective of relevant stakeholders. PURPOSE: The aim of this study was to identify the burden of DRE (clinical, quality of life, and economic) and the unmet needs in Spain and to determine what represents value in the treatment of FOS in DRE patients from the perspective of Spanish epileptologists. METHODS: The steps taken to carry out the MCDA were based on previously published good methodological practices. A systematic literature review (combining biomedical databases and gray literature sources) was performed between March and April 2020. Results were reviewed and validated with three epileptologists in June 2020 and used to develop a MCDA value framework, adapted for FOS in DRE, composed of 12 quantitative criteria and 3 contextual criteria. A group of six Spanish epileptologists from four Spanish regions were trained in MCDA methodology before individually validating value criteria (and their definitions based on literature review findings) and assigned relative weights using an ordinal 6-points scale. Results were analyzed and discussed in a group meeting through reflective MCDA discussion methodology. RESULTS: Drug-resistant epilepsy is considered a very severe health problem with important unmet needs affecting a considerably sized population. While safety and impact on quality of life of available ASMs are considered adequate, efficacy remains insufficient for patients to achieve seizure freedom and maintain it over time. Hence, the therapeutic benefit of pharmacological treatments currently used is regarded as suboptimal. Drug-resistant epilepsy management is associated with moderate pharmacological, relevant direct medical and high indirect costs. Quality of evidence available for current treatments is moderate. It is considered that DRE does not currently stand as a key priority for the Spanish healthcare system. CONCLUSIONS: Drug-resistant epilepsy is considered a very severe health problem associated with relevant unmet needs. These include the lack of availability of specific treatment protocols, the need to improve early diagnosis by increasing the number of referrals to specialized epilepsy units and the availability of specific ASMs with improved efficacy and safety profiles, allowing to reach treatment objectives. Reflective MCDA provided a standardized, transparent approach to evaluate multiple criteria ascertaining what represents value from a holistic point of view and from the perspective of clinical experts, facilitating decision-making.

Beneficial Effects of Metformin on the Central Nervous System, with a Focus on Epilepsy and Lafora Disease.

Metformin is a drug in the family of biguanide compounds that is widely used in the treatment of type 2 diabetes (T2D). Interestingly, the therapeutic potential of metformin expands its prescribed use as an anti-diabetic drug. In this sense, it has been described that metformin administration has beneficial effects on different neurological conditions. In this work, we review the beneficial effects of this drug as a neuroprotective agent in different neurological diseases, with a special focus on epileptic disorders and Lafora disease, a particular type of progressive myoclonus epilepsy. In addition, we review the different proposed mechanisms of action of metformin to understand its function at the neurological level.

Neuroinflammation and progressive myoclonus epilepsies: from basic science to therapeutic opportunities.

Progressive myoclonus epilepsies (PMEs) are a group of genetic neurological disorders characterised by the occurrence of epileptic seizures, myoclonus and progressive neurological deterioration including cerebellar involvement and dementia. The primary cause of PMEs is variable and alterations in the corresponding mutated genes determine the progression and severity of the disease. In most cases, they lead to the death of the patient after a period of prolonged disability. PMEs also share poor information on the pathophysiological bases and the lack of a specific treatment. Recent reports suggest that neuroinflammation is a common trait under all these conditions. Here, we review similarities and differences in neuroinflammatory response in several PMEs and discuss the window of opportunity of using anti-inflammatory drugs in the treatment of several of these conditions.

Emergency implementation of telemedicine for epilepsy in Spain: Results of a survey during SARS-CoV-2 pandemic.

Teleneurology in Spain had not been implemented so far in clinical practice, except in urgent patients with stroke. Telemedicine was hardly used in epilepsy, and patients and neurologists usually preferred onsite visits. Our goal was to study impressions of adult and pediatric epileptologists about the use of telemedicine after emergent implementation during the new coronavirus 2019 (COVID-19) pandemic. METHODS: An online survey was sent to the members of the Spanish Epilepsy Society and the members of the Epilepsy Study Group of the Catalan Neurological Society, inquiring about different aspects of telemedicine in epilepsy during the pandemic lockdown. RESULTS: A total of 66 neurologists responded, mostly adult neurologists (80.3%), the majority with a monographic epilepsy clinic (4 out of 5). Of all respondents, 59.1% reported to attend more than 20 patients with epilepsy (PWE) a week. During the pandemic, respondents handled their epilepsy clinics mainly with telephone calls (88%); only 4.5% used videoconference. Changes in antiseizure medications were performed less frequently than during onsite visits by 66.6% of the epileptologists. Scales were not administered during these visits, and certain types of information such as sudden expected unrelated death in epilepsy (SUDEP) were felt to be more appropriate to discuss in person. More than 4 out of 5 of the neurologists (84.8%) stated that they would be open to perform some telematic visits in the future. CONCLUSIONS: In Spain, emergent implantation of teleneurology has shown to be appropriate for the care of many PWE. Technical improvements, extended use of videoconference and patient selection may improve results and patient and physician satisfaction.

The 5th International Lafora Epilepsy Workshop: Basic science elucidating therapeutic options and preparing for therapies in the clinic.

Lafora disease (LD) is both a fatal childhood epilepsy and a glycogen storage disease caused by recessive mutations in either the Epilepsy progressive myoclonus 2A (EPM2A) or EPM2B genes. Hallmarks of LD are aberrant, cytoplasmic carbohydrate aggregates called Lafora bodies (LBs) that are a disease driver. The 5th International Lafora Epilepsy Workshop was recently held in Alcala de Henares, Spain. The workshop brought together nearly 100 clinicians, academic and industry scientists, trainees, National Institutes of Health (NIH) representation, and friends and family members of patients with LD. The workshop covered aspects of LD ranging from defining basic scientific mechanisms to elucidating a LD therapy or cure and a recently launched LD natural history study.

Structural and Functional Brain Abnormalities in Mouse Models of Lafora Disease.

Mutations in the EPM2A and EPM2B genes, encoding laforin and malin proteins respectively, are responsible for Lafora disease, a fatal form of progressive myoclonus epilepsy with autosomal recessive inheritance. Neuroimaging studies of patients with Lafora disease have shown different degrees of brain atrophy, decreased glucose brain uptake and alterations on different brain metabolites mainly in the frontal cortex, basal ganglia and cerebellum. Mice deficient for laforin and malin present many features similar to those observed in patients, including cognitive, motor, histological and epileptic hallmarks. We describe the neuroimaging features found in two mouse models of Lafora disease. We found altered volumetric values in the cerebral cortex, hippocampus, basal ganglia and cerebellum using magnetic resonance imaging (MRI). Positron emission tomography (PET) of the cerebral cortex, hippocampus and cerebellum of Epm2a-/- mice revealed abnormal glucose uptake, although no alterations in Epm2b-/- mice were observed. Magnetic resonance spectroscopy (MRS) revealed significant changes in the concentration of several brain metabolites, including N-acetylaspartate (NAA), in agreement with previously described findings in patients. These data may provide new insights into disease mechanisms that may be of value for developing new biomarkers for diagnosis, prevention and treatment of Lafora disease using animal models.

Lafora disease offers a unique window into neuronal glycogen metabolism.

Lafora disease (LD) is a fatal, autosomal recessive, glycogen-storage disorder that manifests as severe epilepsy. LD results from mutations in the gene encoding either the glycogen phosphatase laforin or the E3 ubiquitin ligase malin. Individuals with LD develop cytoplasmic, aberrant glycogen inclusions in nearly all tissues that more closely resemble plant starch than human glycogen. This Minireview discusses the unique window into glycogen metabolism that LD research offers. It also highlights recent discoveries, including that glycogen contains covalently bound phosphate and that neurons synthesize glycogen and express both glycogen synthase and glycogen phosphorylase.

Eslicarbazepine acetate as monotherapy in clinical practice: Outcomes from Euro-Esli.

OBJECTIVES: To assess the effectiveness and safety/tolerability of eslicarbazepine acetate (ESL) monotherapy in clinical practice in Europe. MATERIALS AND METHODS: Euro-Esli was a pooled analysis of 14 European clinical practice studies. Responder rate (≥50% seizure frequency reduction) and seizure freedom rate (seizure freedom at least since prior visit) were assessed after 3, 6 and 12 months of ESL treatment and at last visit. Adverse events (AEs) and AEs leading to ESL discontinuation were assessed throughout follow-up. A subanalysis was conducted to assess outcomes for patients treated initially with ESL monotherapy and for patients treated at the last visit with ESL monotherapy. RESULTS: ESL was used as monotherapy in 88/2045 (4.3%) patients initially and in 229/1340 (17.1%) patients at the last visit. At 12 months, responder and seizure freedom rates were 94.1% and 88.2%, respectively, in patients treated initially with ESL monotherapy, and 93.2% and 77.4%, respectively, in patients treated at the last visit with ESL monotherapy. Corresponding values for patients treated initially with ESL adjunctive therapy were 74.8% and 39.0%, respectively; and for patients treated at the last visit with ESL adjunctive therapy, corresponding values were 70.4% and 25.9%, respectively. Safety and tolerability were generally comparable in patients treated with ESL as monotherapy or adjunctive therapy. The most commonly reported AEs (≥5% of patients in any group) were dizziness, somnolence, instability/ataxia, and fatigue. CONCLUSIONS: These clinical practice data support the use of ESL as monotherapy, as well as adjunctive therapy, for focal-onset seizures, complementing evidence from clinical trials.

Clinical outcomes of eslicarbazepine acetate monotherapy for focal-onset seizures: A multicenter audit.

OBJECTIVE: To assess the effectiveness and tolerability of eslicarbazepine acetate (ESL) monotherapy in routine clinical practice for the treatment of focal-onset seizures. METHODS: Multicenter, retrospective, observational study conducted in patients older than 16 years treated with ESL as first-line monotherapy or converted to ESL monotherapy from polytherapy or other monotherapy. Outcomes included 1-year retention rate, seizure-free rates after 6 and 12 months of monotherapy treatment, and safety/tolerability issues. RESULTS: A total of 256 patients were included (106 first-line and 150 conversion to monotherapy; 56 patients aged >65 years). Overall, the 1-year retention rate was 79% (72.7% in the ≥65 years subgroup) and seizure-free rates at 6 and 12 months were 59.3% and 55.3% (72.2% and 67.3% in the ≥65 years subgroup), without significant differences when comparing first-line vs conversion-to-ESL monotherapy groups (P = .979). However, the conversion group was heterogeneous and included 43 (29.1%) patients that were seizure free the year prior ESL introduction. A substantially higher proportion of patients remained seizure free for the entire follow-up among those who initiated ESL due to tolerability problems compared with those treated due to inadequate seizure control (71.4% vs 37.3%). Overall, 62 of 256 (24.2%) patients reported AEs (39.3% in >65 years subgroup) and led to discontinuation in 20/256 (7.8%) patients (12.5% in >65 years subgroup). Commonly reported AEs were somnolence (6.6%), dizziness (6.3%), and headache (4.3%). Hyponatremia was recorded in five patients, the majority (4/5) of whom were older than 65 years. CONCLUSIONS: Eslicarbazepine acetate was effective and well-tolerated as first-line or conversion to monotherapy in a clinical setting in adult and elderly patients with focal-onset seizures.

Clinical spectrum and genotype-phenotype associations of KCNA2-related encephalopathies.

Recently, de novo mutations in the gene KCNA2, causing either a dominant-negative loss-of-function or a gain-of-function of the voltage-gated K+ channel Kv1.2, were described to cause a new molecular entity within the epileptic encephalopathies. Here, we report a cohort of 23 patients (eight previously described) with epileptic encephalopathy carrying either novel or known KCNA2 mutations, with the aim to detail the clinical phenotype associated with each of them, to characterize the functional effects of the newly identified mutations, and to assess genotype-phenotype associations. We identified five novel and confirmed six known mutations, three of which recurred in three, five and seven patients, respectively. Ten mutations were missense and one was a truncation mutation; de novo occurrence could be shown in 20 patients. Functional studies using a Xenopus oocyte two-microelectrode voltage clamp system revealed mutations with only loss-of-function effects (mostly dominant-negative current amplitude reduction) in eight patients or only gain-of-function effects (hyperpolarizing shift of voltage-dependent activation, increased amplitude) in nine patients. In six patients, the gain-of-function was diminished by an additional loss-of-function (gain-and loss-of-function) due to a hyperpolarizing shift of voltage-dependent activation combined with either decreased amplitudes or an additional hyperpolarizing shift of the inactivation curve. These electrophysiological findings correlated with distinct phenotypic features. The main differences were (i) predominant focal (loss-of-function) versus generalized (gain-of-function) seizures and corresponding epileptic discharges with prominent sleep activation in most cases with loss-of-function mutations; (ii) more severe epilepsy, developmental problems and ataxia, and atrophy of the cerebellum or even the whole brain in about half of the patients with gain-of-function mutations; and (iii) most severe early-onset phenotypes, occasionally with neonatal onset epilepsy and developmental impairment, as well as generalized and focal seizures and EEG abnormalities for patients with gain- and loss-of-function mutations. Our study thus indicates well represented genotype-phenotype associations between three subgroups of patients with KCNA2 encephalopathy according to the electrophysiological features of the mutations.

Tau-Induced Pathology in Epilepsy and Dementia: Notions from Patients and Animal Models.

Patients with dementia present epilepsy more frequently than the general population. Seizures are more common in patients with Alzheimer's disease (AD), dementia with Lewy bodies (LBD), frontotemporal dementia (FTD) and progressive supranuclear palsy (PSP) than in other dementias. Missense mutations in the microtubule associated protein tau (MAPT) gene have been found to cause familial FTD and PSP, while the P301S mutation in MAPT has been associated with early-onset fast progressive dementia and the presence of seizures. Brains of patients with AD, LBD, FTD and PSP show hyperphosphorylated tau aggregates, amyloid-ß plaques and neuropil threads. Increasing evidence suggests the existence of overlapping mechanisms related to the generation of network hyperexcitability and cognitive decline. Neuronal overexpression of tau with various mutations found in FTD with parkinsonism-linked to chromosome 17 (FTDP-17) in mice produces epileptic activity. On the other hand, the use of certain antiepileptic drugs in animal models with AD prevents cognitive impairment. Further efforts should be made to search for plausible common targets for both conditions. Moreover, attempts should also be made to evaluate the use of drugs targeting tau and amyloid-ß as suitable pharmacological interventions in epileptic disorders. The diagnosis of dementia and epilepsy in early stages of those diseases may be helpful for the initiation of treatments that could prevent the generation of epileptic activity and cognitive deterioration.

Sodium selenate treatment improves symptoms and seizure susceptibility in a malin-deficient mouse model of Lafora disease.

OBJECTIVE: To search for new therapies aimed at ameliorating the neurologic symptoms and epilepsy developing in patients with Lafora disease. METHODS: Lafora disease is caused by loss-of-function mutations in either the EPM2A or EPM2B genes. Epm2a-/- and Epm2b-/- mice display neurologic and behavioral abnormalities similar to those found in patients. Selenium is a potent antioxidant and its deficiency has been related to the development of certain diseases, including epilepsy. In this study, we investigated whether sodium selenate treatment improved the neurologic alterations and the hyperexcitability present in the Epm2b-/- mouse model. RESULTS: Sodium selenate ameliorates some of the motor and memory deficits and the sensitivity observed with pentylenetetrazol (PTZ) treatments in Epm2b-/- mice. Neuronal degeneration and gliosis were also diminished after sodium selenate treatment. SIGNIFICANCE: Sodium selenate could be beneficial for ameliorating some symptoms that present in patients with Lafora disease.