A systematic review and meta-analysis of factors related to first line drugs refractoriness in patients with juvenile myoclonic epilepsy (JME).

INTRODUCTION: Juvenile Myoclonic Epilepsy (JME) is a prevalent form of epileptic disorder, specifically categorized within the realm of Genetic Generalized Epilepsy (GGE). Its hallmark features encompass unprovoked bilateral myoclonus and tonic-clonic seizures that manifest during adolescence. While most JME patients respond favorably to anti-seizure medication (ASM), a subset experiences refractory JME, a condition where seizures persist despite rigorous ASM treatment, often termed "Drug-Resistant Epilepsy" (DRE). This systematic review and meta-analysis aims to determine the prevalence of refractory JME, and further to identify socio-demographic, electrophysiological and clinical risk factors associated with its occurrence. Pinpointing these factors is crucial as it offers the potential to predict ASM responsiveness, enabling early interventions and tailored care strategies for patients. MATERIAL AND METHODS: The systematic review and meta-analysis followed the Cochrane Handbook and adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The study evaluated outcomes post ASM treatment in JME cohorts by searching papers published up to September 2023 in PubMed/MEDLINE, Scopus, and Google Scholar databases. Predefined inclusion criteria were met by 25 eligible studies, forming the basis for analysis. RESULTS: A total of 22 potential risk factors for refractory JME were documented. Notably, robust risk factors for treatment resistance included Psychiatric Disorder (Odds Ratio (OR), 3.42 [2.54, 4.61] (95% Confidence Inverval (Cl)), Febrile Seizures (OR, 1.83 [1.14, 2.96] (95% Cl)), Alcohol Consumption (OR, 16.86 [1.94, 146.88] (95%Cl)), Aura (OR, 2.15 [1.04, 4.47] (95%Cl)), childhood absence epilepsy (CAE) evolving into JME (OR, 4.54 [1.61, 12.78] (95%CI)), occurrence of three seizure types (OR, 2.96 [1.96, 4.46] (95%CI)), and Focal EEG abnormalities (OR, 1.85 [1.13, 3.01] (95%Cl)). In addition, there were some non-significant risk factors for DRE because of noticeable heterogeneity. CONCLUSION: In aggregate, over 36% of JME patients demonstrated drug resistance, with seven significant risk factors closely linked to this refractoriness. The interplay between these factors and whether they denote treatment non-response or heightened disease burden remains an open question and more studies would be required to fully examine their influence.

Structural insights of novel mutational frames in Bromodomain Containing-2 gene (BRD2) in juvenile myoclonic epilepsy: bed, bench, and laptop profiles.

PURPOSE: Juvenile myoclonic epilepsy (JME) is an adolescent onset type of idiopathic generalized epilepsies. Bromodomain containing protein-2 gene (BRD2), a transcriptional regulatory protein, has a susceptible role in the expression of JME. Considering the polymorphic variations observed in exon 3 of the BRD2 gene, we evaluated the molecular interactions with anti-seizure medication in individuals diagnosed with JME. METHODS: The genomic DNA was extracted from 5 mL of peripheral venous blood of JME participants (n = 55) and healthy control subjects (n = 55). Detailed anti-seizure medication and outcomes were noted during the study period. Identified novel mutations at nucleotide and protein sequences, compared by multiple sequence alignment. Wild-type (WT) and mutated-type (MT) structures were investigated for molecular docking and interactions with anti-seizure drugs. RESULTS: A common variant at c.1707G>A was found among 23 participants, while a single variant at c.1663ins C was found in one participant. The deletion positions were observed at c.1890delA, c.1892A>T, c.1895A>T, c.1896G>T, c.1897T>C, c.1898T>C, c.1899C>T, c.1900G>T, c.1901C>T and c.1902A>T exhibiting stop codon after p.111Pro>stop; these variants resulted in a truncated protein. In silico analysis was conducted to validate changes; docking analysis showed that novel variant has a significant role in the interactions with anti-seizure drugs. SIGNIFICANCE: Besides clinical and genetic outcomes, ∼5.45% unique genetical variations were observed in the participants. Significant mimicked at the binding site position (92-111) of human BRD2 ranges ∼8.2%, ∼16.4%, and ∼10.6%. Further, research is needed to identify the importance of polymorphism alterations at the binding site and their molecular interactions with anti-seizure drugs, which might be confirmed in a diverse population with JME.

Differential diagnosis of familial adult myoclonic epilepsy.

OBJECTIVE: Familial adult myoclonic epilepsy (FAME) is an under-recognized disorder characterized by cortical myoclonus, generalized tonic-clonic seizures, and additional clinical symptoms, which vary depending on the FAME subtype. FAME is caused by pentanucleotide repeat expansions of intronic TTTCA/TTTTA in different genes. FAME should be distinguished from a range of differential diagnoses. METHODS: The differential diagnoses and frequent presentations leading to misdiagnosis of FAME were investigated from the available literature and reported based on an expert opinion survey. RESULTS: The phenotypic features of FAME, including generalized tonic-clonic and myoclonic seizures, are also seen in other epilepsy syndromes, such as juvenile myoclonic epilepsy, with a resultant risk of misdiagnosis and lack of identification of the underlying cause. Cortical myoclonus may mimic essential tremor or drug-induced tremor. In younger individuals, the differential diagnosis includes progressive myoclonus epilepsies (PMEs), such as Unverricht-Lundborg disease, whereas, in adulthood, late-onset variants of PMEs, such as sialidoses, myoclonus epilepsy, and ataxia due to potassium channel pathogenic variants should be considered. PMEs may also be suggested by cognitive impairment, cerebellar signs, or psychiatric disorders. Electroencephalography (EEG) may show similarities to other idiopathic generalized epilepsies or PMEs, with generalized spike-wave activity. Signs of cortical hyperexcitability may be seen, such as an increased amplitude of somatosensory evoked potentials or enhanced cortical reflex to sensory stimuli, together with the neurophysiological pattern of the movement disorder. SIGNIFICANCE: Recognition of FAME will inform prognostic and genetic counseling and diagnosis of the insidious progression, which may occur in older individuals who show mild cognitive deterioration. Distinguishing FAME from other disorders in individuals or families with this constellation of symptoms is essential to allow the identification of underlying etiology.

Leu226Trp CACNA1A variant associated with juvenile myoclonic epilepsy with and without intellectual disability.

OBJECTIVE: Epilepsy is a disease of Central Nervous System (CNS) characterized by abnormal brain activity and recurrent seizures and is considered a clinically and genetically heterogeneous disease. Here, we investigated pathogenic genetic alteration and described the clinical characteristics of three Iranian family members affected by Idiopathic Generalized Epilepsy (IGE) with and without intellectual disability. METHODS: A non-consanguineous Iranian family with juvenile myoclonic epilepsy was enrolled in the study. The comprehensive neurological evaluation included motor and sensory skills, vision, hearing, speech, coordination, and mood. Whole-exome Sequencing (WES) was performed on the proband to detect probable pathogenic variant, and after the filtering process, probable variants were evaluated with familial segregation analysis using Sanger sequencing. RESULTS: Using WES, we identified a heterozygous missense substitution (NM_023035.3:c.T677G:p.Leu226Trp) in CACNA1A gene in the studied family with juvenile myoclonic epilepsy with and without intellectual disability and psychiatric phenotype. Considering the patients' clinical synopsis, familial segregation analysis, and literature review, we postulated this variant to be causative of the disease. Indeed, the resulting missense mutation of Leu226Trp affects a highly conserved residue supporting our hypothesis that this mutation is potentially pathogenic. CONCLUSION: To the best of our knowledge, this is the first report of juvenile myoclonic epilepsy related to CACNA1A gene. Our results provide evidence for expanding the clinical and molecular findings related to the CACNA1A gene.

Mutational Analysis of Myoclonin1 Gene in Pakistani Juvenile Myoclonic Epilepsy Patients.

Juvenile myoclonic epilepsy (JME) is the most prevalent and genetically heterogeneous form of epilepsy and accounts for 10-30% of all the cases worldwide. Ef-hand domain- (c-terminal-) containing protein 1 (EFHC1) encodes for a nonion channel protein and mutations in this gene have been extensively reported in different populations to play a causative role in JME. Linkage between JME and 6p11-12 locus has already been confirmed in Mexican and Dutch families. A case-control study was conducted on Pakistani JME patients for the first time, aimed at finding out EFHC1 mutations that have been reported in different populations. For this purpose, 66 clinically diagnosed JME patients and 108 control subjects were included in the study. Blood samples were collected from all the participants, and DNA was isolated from the lymphocytes by the modified organic method. Total 3 exons of EFHC1, harboring extensively reported mutations, were selected for genotypic analysis. We identified three heterozygous variants, R159W, V460A, P436P, and one insertion in the current study. V460A, an uncommon variant identified herein, has recently been reported in public databases in an unphenotyped American individual. This missense variant was found in 3 Pakistani JME patients from 2 unrelated families. However, in silico analysis showed that V460A may possibly be a neutral variant. While the absence of a majority of previously reported mutations in our population suggests that most of the mutations of EFHC1 are confined to particular ethnicities and are not evenly distributed across the world. However, to imply the causation, the whole gene and larger number of JME patients should be screened in this understudied population.

Electroencephalographic findings in asymptomatic relatives of patients with juvenile myoclonic epilepsy: relationship with the degree of kinship.

INTRODUCTION: A prevalence of 1 to 71% of electroencephalogram (EEG) abnormalities has been reported in asymptomatic relatives of patients with juvenile myoclonic epilepsy (JME). OBJECTIVE: To determine the frequency of EEG abnormalities in asymptomatic relatives of patients with JME according to the degree of kinship. METHODS: Prospective, analytical study. First-, second, and third-degree relatives of patients with JME who agreed to participate and signed informed consent were included. The analysis was descriptive, bivariate. RESULTS: 209 asymptomatic relatives were included, out of which 115 (55%) were females and 94 (45%) were males, with a mean age of 35.9 ± 16.9 (range between 6 and 73 years). Forty-four (21.1%) relatives had abnormal EEGs. First-degree relatives (12%) had abnormalities more frequently in comparison with second- and third-degree relatives (p = 0.007). CONCLUSIONS: EEG abnormalities were observed in one third of asymptomatic relatives. It is important to highlight that there were more alterations among first-degree relatives. In the future, these findings might enable for the risk of clinically developing the disease to be estimated and for genetic counseling to be provided.

INTRODUCCIÓN: Se ha reportado de 1 a 71 % de prevalencia de anormalidades en el electroencefalograma (EEG) de familiares asintomáticos de pacientes con epilepsia mioclónica juvenil (EMJ). OBJETIVO: Determinar la frecuencia de anormalidades en el EEG en familiares asintomáticos de pacientes con EMJ de acuerdo con el grado de parentesco. MÉTODOS: Estudio prospectivo y analítico. Se incluyeron familiares de primer, segundo y tercer grado de pacientes con EMJ, quienes aceptaron participar y firmaron el consentimiento informado. El análisis fue descriptivo bivariado. RESULTADOS: Se incluyeron 209 familiares asintomáticos, 115 (55 %) mujeres y 94 (45 %) hombres, con edad media de 35.9 ± 16.9 (rango entre seis y 73 años); 44 familiares (21.1 %) tuvieron EEG anormal. Los familiares de primer grado (12 %) cursaron con mayor frecuencia con anormalidades en comparación con los de segundo y tercer grado (p = 0.007). CONCLUSIONES: Se observaron anormalidades en el EEG de una tercera parte de los familiares asintomáticos. Es importante resaltar que existieron más alteraciones entre los familiares de primer grado. En un futuro, estos hallazgos permitirán estimar el riesgo de desarrollar la enfermedad clínicamente y brindar consejo genético.

Persistent treatment resistance in genetic generalized epilepsy: A long-term outcome study in a tertiary epilepsy center.

OBJECTIVE: To assess prognostic patterns and investigate clinical and electroencephalography (EEG) variables associated with persistent treatment resistance in a population of genetic generalized epilepsy (GGE) patients with a long-term follow-up. METHODS: Data from GGE patients followed from 1975 to 2019 were reviewed retrospectively. Subjects with a follow-up >10 years, starting from epilepsy diagnosis, were included. Persistent treatment resistance was defined as the absence of any period of remission ≥1 year despite treatment with two appropriate and adequate antiepileptic drugs (AEDs). RESULTS: One hundred ninety-nine patients were included. The median age was 39.5 years (interquartile range [IQR] 30-49) and the median follow-up was 27 years (IQR 18-35). The most common syndrome was juvenile myoclonic epilepsy (JME), diagnosed in 44.2% of patients. During follow-up, 163 subjects (81.9%) experienced 3-year remission from any seizure type, whereas 5- and 10-year remission occurred in 141 (70.8%) and 92 (46.2%) cases, respectively. The most common prognostic pattern was a relapsing-remitting course, observed in 80 patients (40.2%), whereas 29 (14.6%) displayed persistent treatment resistance. According to multivariable logistic regression analysis, febrile seizures (FS), specific EEG patterns (namely generalized paroxysmal fast activity, GPFA) and valproate (VPA) resistance were the only variables significantly associated with persistent treatment resistance. JME was the only epilepsy syndrome statistically associated with persistent treatment resistance in univariable logistic regression analysis. SIGNIFICANCE: Persistent treatment resistance was observed in almost 15% of GGE patients followed in a tertiary epilepsy center. A worse outcome was associated with specific clinical variables (JME, FS) and EEG patterns (GPFA).

The presenting symptoms of Lafora Disease: An electroclinical and genetic study in five Apulian (Southern Italy) families.

PURPOSE: To elucidate the presenting symptoms of Lafora Disease (LD) to differentiate it from Juvenile Myoclonic Epilepsy (JME). METHODS: We collected and evaluated the early electroclinical data of 5 unrelated Apulian (Southern Italy) LD families, 30 LD patients selected from the literature, and 30 Apulian JME patients. RESULTS: The Apulian LD patients presented with generalised tonic-clonic and focal visual seizures, followed by myoclonic seizures and action-postural myoclonus. In these patients, EEG background slowing and occipital epileptiform abnormalities were significantly more evident than in the other groups. Genetic analysis revealed the presence of mutations in the EPM2A gene in 4 families, and in the NHLRC1 gene in the remaining family. In detail, we identified 2 different point mutations in EPM2A and only 1 in NHLRC1, and expanded the molecular spectrum of the EPM2A gene mutations reporting for the first time a patient carrier of the c.243_246del genetic variant. In the previously reported LD cases, generalised tonic-clonic and focal visual seizures and myoclonus were the most frequent symptoms, as confirmed by the first EEGs showing occipital or diffuse epileptiform abnormalities with photosensitivity in the background activity slowing. In the Apulian JME patients, myoclonus appeared earlier, usually at awakening, with diffuse epileptiform abnormalities during sleep and photosensitivity in the normal background activity. The diagnosis of JME was established much earlier than the LD one. During evolution, unlike JME patients, LD patients showed a significant resistance to drugs. CONCLUSIONS: Tonic-clonic and focal visual seizures followed by myoclonic seizures and action-postural myoclonus together with EEG background slowing with diffuse and occipital epileptiform abnormalities suggest a diagnosis of LD. An early molecular confirmation allows a better diagnosis, counselling and management of affected patients and their families, and it may be useful to improve the patients' quality of life using, when possible, emerging personalized treatments that may slow the evolution of the disease.

Revisiting the clinical impact of variants in EFHC1 in patients with different phenotypes of genetic generalized epilepsy.

The most common form of genetic generalized epilepsy (GGE) is juvenile myoclonic epilepsy (JME), which accounts for 5 to 10% of all epilepsy cases. The gene EFHC1 has been implicated as a putative cause of JME. However, it remains debatable whether testing for EFHC1 mutations should be included in the diagnostic epilepsy gene panels. To investigate the clinical utility of EFHC1 testing, we studied 125 individuals: 100 with JME and 25 with other GGEs. We amplified and sequenced all EFHC1 coding exons. Then, we predicted the pathogenicity or benign impact of the variants using the analyses proposed by the American College of Medical Genetics and Genomics (ACMG)/Association for Molecular Pathology (AMP). Mutation screening revealed 11 missense variants in 44 probands with JME (44%) and one of the seven individuals with generalized tonic-clonic seizures on awakening (14%). Six of the 11 variants (54%) were classified as 'benign,' and the remaining variants were considered variants of uncertain significance (VUS). There is currently a limitation to test for genes that predispose an individual to complex, nonmonogenic phenotypes. Thus, we show suggestive evidence that EFHC1 testing lacks a scientific foundation based on the disputed nature of the gene-disease relationship and should be currently limited to research purposes.

Network characteristics of genetic generalized epilepsy: Are the syndromes distinct?

OBJECTIVES: This study evaluated the structural and functional connectivity of patients with genetic generalized epilepsy (GGE) compared to healthy subjects. We also investigated whether there are differences in structural and functional connectivity among different GGE syndromes. METHODS: We enrolled 100 patients with a clinical diagnosis of GGE. The patients were classified into different syndrome groups(12 cases of childhood absence epilepsy, 13 cases of juvenile absence epilepsy, 56 cases of juvenile myoclonic epilepsy, and 19 cases of epilepsy with GTC alone). We applied graph theoretical analysis to structural brain volumes and EEG to evaluate structural and functional connectivity in the GGE patients. RESULTS: The global network measures showed significant differences in the structural and functional connectivity between the patients with GGE and the healthy controls, and the local network measures revealed hub reorganization in the GGE patients. The global efficiency, local efficiency, and clustering coefficients of the structural connectivity were significantly decreased, whereas the characteristic path length and small-worldness index were increased in the GGE patients. The global efficiency and local efficiency were increased and the small-worldness index decreased in the functional connectivity. The patients with juvenile myoclonic epilepsy had the most extensive changes in structural and functional connectivity compared to the healthy subjects. SIGNIFICANCE: This study's main finding is that structural and functional connectivity in patients with GGE is significantly different from that in healthy controls. We find that the different GGE syndromes show distinct structural and functional connectivity, which can lead further understanding of the pathogenesis of GGE syndromes.

Trait impulsivity correlates with active myoclonic seizures in genetic generalized epilepsy.

BACKGROUND: Juvenile myoclonic epilepsy (JME) is a common subtype of genetic generalized epilepsy (GGE) arising in adolescence and is often associated with executive function (EF) deficits. Some EF components like response inhibition have been extensively evaluated in JME, but few studies have focused upon trait impulsivity or compared between GGE subtypes. The aim of the present study was to compare the association of trait impulsivity in JME with other GGE subtypes. METHODS: Patients with GGE aged between 14 and 40 years (n = 137) were divided into those with JME (n = 92) and those with other GGEs (n = 45: 8 childhood absence epilepsy (CAE), 22 juvenile absence epilepsy (JAE), and 15 epilepsy with generalized tonic-clonic seizures only (EGTCS)). The study participants were recruited through medical records of the general population of Buskerud County and the neighboring municipalities, covering 477,000 people or 9.1% of Norway's total population. All participants underwent a clinical interview including the Barratt Impulsiveness Scale (BIS), an established measure of trait impulsivity. We controlled for other potential predictors of BIS score using analysis of covariance (ANCOVA). RESULTS: There were no differences between JME and other types of GGE for BIS scores, but the presence of myoclonic seizures within the last year, irrespective of GGE subtype, was independently associated with significantly increased behavioral impulsivity. CONCLUSIONS: This study demonstrates that trait impulsivity in GGE is most strongly related to the recent occurrence of myoclonic seizures rather than GGE subtype.

A familial t(4;8) translocation segregates with epilepsy and migraine with aura.

Three relatives carrying a t(4;8)(p15.2;p23.2) translocation had juvenile myoclonic epilepsy, self-limited photosensitive occipital epilepsy and migraine with aura. The t(4;8) translocation interrupted the coding sequence of CSMD1 gene and occurred immediately to the 3'UTR of STIM2 gene. STIM2 was overexpressed in the patient carrying the unbalanced translocation, and all three individuals had a single functional copy of CSMD1. Array CGH study disclosed that these three individuals also carried a deletion at 5q12.3 that involves the RGS7BP gene. The overall results favor the view that CSMD1, STIM2, and RGS7BP genes could contribute to epilepsy and migraine phenotypes in our family.

Functional Alterations in Ciliogenesis-Associated Kinase 1 (CILK1) that Result from Mutations Linked to Juvenile Myoclonic Epilepsy.

Ciliopathies are a group of human genetic disorders associated with mutations that give rise to the dysfunction of primary cilia. Ciliogenesis-associated kinase 1 (CILK1), formerly known as intestinal cell kinase (ICK), is a conserved serine and threonine kinase that restricts primary (non-motile) cilia formation and length. Mutations in CILK1 are associated with ciliopathies and are also linked to juvenile myoclonic epilepsy (JME). However, the effects of the JME-related mutations in CILK1 on kinase activity and CILK1 function are unknown. Here, we report that JME pathogenic mutations in the CILK1 N-terminal kinase domain abolish kinase activity, evidenced by the loss of phosphorylation of kinesin family member 3A (KIF3A) at Thr672, while JME mutations in the C-terminal non-catalytic domain (CTD) have little effect on KIF3A phosphorylation. Although CILK1 variants in the CTD retain catalytic activity, they nonetheless lose the ability to restrict cilia length and also gain function in promoting ciliogenesis. We show that wild type CILK1 predominantly localizes to the base of the primary cilium; in contrast, JME variants of CILK1 are distributed along the entire axoneme of the primary cilium. These results demonstrate that JME pathogenic mutations perturb CILK1 function and intracellular localization. These CILK1 variants affect the primary cilium, independent of CILK1 phosphorylation of KIF3A. Our findings suggest that CILK1 mutations linked to JME result in alterations of primary cilia formation and homeostasis.

Whole exome sequencing identifies a novel SCN1A mutation in genetic (idiopathic) generalized epilepsy and juvenile myoclonic epilepsy subtypes.

INTRODUCTION: Genetic (idiopathic) generalized epilepsy (GGE) is a common form of epilepsy characterized by unknown aetiology and a presence of genetic component in its predisposition. METHODS: To understand the genetic factor in a family with GGE, we performed whole exome sequencing (WES) on a trio of a juvenile myoclonic epilepsy/febrile seizure (JME/FS) proband with JME/FS mother and healthy father. Sanger sequencing was carried out for validation of WES results and variant detection in other family members. RESULTS: Predictably damaging variant found in affected proband and mother but absent in healthy father in SCN1A gene was found to be associated with generalized epilepsy and febrile seizure. The novel non-synonymous substitution (c.5753C>T, p.S1918F) in SCN1A was found in all family members with GGE, of which 4/8 were JME subtypes, and/or febrile seizure, while 3 healthy family member controls did not have the mutation. This mutation was also absent in 41 GGE patients and 414 healthy Malaysian Chinese controls. CONCLUSION: The mutation is likely to affect interaction between the sodium channel and calmodulin and subsequently interrupt calmodulin-dependent modulation of the channel.

Levetiracetam in genetic generalized epilepsy: A prospective unblinded active-controlled trial.

PURPOSE: To compare the efficacy and tolerability of levetiracetam (LEV) versus valproate (VPA) monotherapy in adults with genetic generalized tonic-clonic seizures alone (GTCS) and juvenile myoclonic epilepsy (JME). METHODS: This study was an open-label, active-controlled trial with a two-parallel-group design. Outcome measures including withdrawal rate and seizure freedom rate at 26th weeks and time to withdrawal, and time to first seizure were compared between LEV and VPA groups. Furthermore, tolerability and development of adverse events (AEs) were investigated and analyzed. RESULTS: One hundred and three patients enrolled the study. 71.1% of patients in LEV group and 29.3% in VPA group were female. By the end of 26th week, seizure freedom rate and withdrawal rate were 88.9% and 8.9% in LEV group and 86.2% and 10.3% in VPA group with no significant difference. Time to first seizure was longer in VPA group (p = 0.32) and time to withdrawal favored LEV (p = 0.51). At least one AE was reported in 37.7% of patients in LEV group and 55.1% in VPA group. The most common AEs were psychiatric symptoms and dizziness in those on LEV and weight gain and dyspepsia in VPA group. CONCLUSION: LEV has similar efficacy and acceptable safety in comparison to VPA in short-term treatment of patients with genetic GTCS and JME, and it could be considered as an alternative to VPA particularly in women of reproductive age.

Cortical activation in generalized seizures.

OBJECTIVE: Patients with generalized epilepsy exhibit different epileptiform events including asymptomatic interictal spikes (IS), absence seizures with spike-wave discharges (SWDs), and myoclonic seizures (MS). Our objective was to determine the spatiotemporal patterns of cortical activation in SWDs, IS, and MS in the Gabra1+/A322D juvenile myoclonic epilepsy mouse. METHODS: We fabricated affordable, flexible high-density electroencephalography (HdEEG) arrays and recorded spontaneous SWD, IS, and MS with video/HdEEG. We determined differences among the events in amplitude spectral density (ASD) in the δ/θ/α/ß/γ frequency bands at baseline (3.5-4.0 seconds before the first spike time, t0 ) and the prespike period (0.1-0.5 seconds before t0 ), and we elucidated the spatiotemporal activation during the t0 spike. RESULTS: All three events had an increase in ASD between baseline and prespike in at least one frequency band. During prespike, MS had the largest δ-band ASD, but SWD had the greatest α/ß/γ band ASD. For all three events, the ASD was largest in the anterior regions. The t0 spike voltage was also greatest in the anterior regions for all three events and IS and MS had larger voltages than SWD. From 7.5 to 17.5 msec after t0 , MS had greater voltage than IS and SWD, and maximal voltage was in the posterior parietal region. SIGNIFICANCE: Changes in spectral density from baseline to prespike indicate that none of these generalized events are instantaneous or entirely unpredictable. Prominent engagement of anterior cortical regions during prespike and at t0 suggest that common anterior neural circuits participate in each event. Differences in prespike ASD signify that although the events may engage similar brain regions, they may arise from distinct proictal states with different neuronal activity or connectivity. Prolonged activation of the posterior parietal area in MS suggests that posterior circuits contribute to the myoclonic jerk. Together, these findings identify brain regions and processes that could be specifically targeted for further recording and modulation.

Juvenile myoclonic epilepsy phenotype in a family with Unverricht-Lundborg disease.

Unverricht-Lundborg disease (ULD), an autosomal recessive progressive myoclonus epilepsy, is due to an expansion, or less commonly a mutation, of the cystatin B (CSTB) gene. We report a clinical and molecular study of a Tunisian ULD family with five affected members presenting with a juvenile myoclonic epilepsy (JME)-like phenotype. The expansion of dodecamers was detected by a deamination/PCR assay. The expression profiles of CSTB and other candidate modifying genes, cathepsin B and cystatin C, were established by quantitative RT-PCR, and their respective transcription levels were compared with those from patients with a classic picture of ULD. Three patients had a fixed phenotype mimicking JME after 29 years of evolution. Only a discrete dysarthria was noticed in the two other patients. No correlation was observed between transcription level and severity of disease. Genetic screening should be performed in patients with a JME-like phenotype, when careful examination reveals discrete atypical signs of JME. This particular phenotype may be due to modifying genes and/or gene-environment interactions which require further clarification.

Abnormal hippocampal structure and function in juvenile myoclonic epilepsy and unaffected siblings.

Juvenile myoclonic epilepsy is the most common genetic generalized epilepsy syndrome, characterized by a complex polygenetic aetiology. Structural and functional MRI studies demonstrated mesial or lateral frontal cortical derangements and impaired fronto-cortico-subcortical connectivity in patients and their unaffected siblings. The presence of hippocampal abnormalities and associated memory deficits is controversial, and functional MRI studies in juvenile myoclonic epilepsy have not tested hippocampal activation. In this observational study, we implemented multi-modal MRI and neuropsychological data to investigate hippocampal structure and function in 37 patients with juvenile myoclonic epilepsy, 16 unaffected siblings and 20 healthy controls, comparable for age, gender, handedness and hemispheric dominance as assessed with language laterality indices. Automated hippocampal volumetry was complemented by validated qualitative and quantitative morphological criteria to detect hippocampal malrotation, assumed to represent a neurodevelopmental marker. Neuropsychological measures of verbal and visuo-spatial learning and an event-related verbal and visual memory functional MRI paradigm addressed mesiotemporal function. We detected a reduction of mean left hippocampal volume in patients and their siblings compared with controls (P < 0.01). Unilateral or bilateral hippocampal malrotation was identified in 51% of patients and 50% of siblings, against 15% of controls (P < 0.05). For bilateral hippocampi, quantitative markers of verticalization had significantly larger values in patients and siblings compared with controls (P < 0.05). In the patient subgroup, there was no relationship between structural measures and age at disease onset or degree of seizure control. No overt impairment of verbal and visual memory was identified with neuropsychological tests. Functional mapping highlighted atypical patterns of hippocampal activation, pointing to abnormal recruitment during verbal encoding in patients and their siblings [P < 0.05, familywise error (FWE)-corrected]. Subgroup analyses indicated distinct profiles of hypoactivation along the hippocampal long axis in juvenile myoclonic epilepsy patients with and without malrotation; patients with malrotation also exhibited reduced frontal recruitment for verbal memory, and more pronounced left posterior hippocampal involvement for visual memory. Linear models across the entire study cohort indicated significant associations between morphological markers of hippocampal positioning and hippocampal activation for verbal items (all P < 0.05, FWE-corrected). We demonstrate abnormalities of hippocampal volume, shape and positioning in patients with juvenile myoclonic epilepsy and their siblings, which are associated with reorganization of function and imply an underlying neurodevelopmental mechanism with expression during the prenatal stage. Co-segregation of abnormal hippocampal morphology in patients and their siblings is suggestive of a genetic imaging phenotype, independent of disease activity, and can be construed as a novel endophenotype of juvenile myoclonic epilepsy.