[Magnetoencephalography in idiopathic generalized epilepsy: comparison with temporal lobe epilepsy].
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Adolescent↗
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Idiopathic generalized epilepsies recognized by the International League Against Epilepsy.
There are eight syndromes currently recognized by the International League Against Epilepsy (ILAE) that would fit the original operational definition of idiopathic generalized epilepsy (IGE) syndromes, including benign myoclonic epilepsy in infancy; generalized epilepsy with febrile seizures plus, an entity in evolution; epilepsy with myoclonic absences; epilepsy with myoclonic-astatic seizures; childhood absence epilepsy; juvenile absence epilepsy; juvenile myoclonic epilepsy; and epilepsy with generalized tonic-clonic seizures only. All of these syndromes can be easily diagnosed when distinctive features are present. In some cases, such features are not present or only appear later in the course of the disease, making it challenging to distinguish the various syndromes. Electroencephalogram (EEG) is the most helpful laboratory test and often will strongly support the diagnosis of IGE, but may not be very helpful in discriminating between several of the syndromes with overlapping features. The same applies for genetic testing, although it is expected that further research exploring the genotype-phenotype relationships will enhance our abilities to make definitive diagnoses. At the current time, clinical features are still the cornerstone of accurate classification, and accurate classification, in turn, is the best predictor of outcome.
Child↗
Generalized epilepsy with febrile seizures plus. A genetic disorder with heterogeneous clinical phenotypes.
The clinical and genetic relationships of febrile seizures and the generalized epilepsies are poorly understood. We ascertained a family with genealogical information in 2000 individuals where there was an unusual concentration of individuals with febrile seizures and generalized epilepsy in one part of the pedigree. We first clarified complex consanguineous relationships in earlier generations and then systematically studied the epilepsy phenotypes in affected individuals. In one branch (core family) 25 individuals over four generations were affected. The commonest phenotype, denoted as 'febrile seizures plus' (FS+), comprised childhood onset (median 1 year) of multiple febrile seizures, but unlike the typical febrile convulsion syndrome, attacks with fever continued beyond 6 years, or afebrile seizures occurred. Seizures usually ceased by mid childhood (median 11 years). Other phenotypes included FS+ and absences, FS+ and myoclonic seizures, FS+ and atonic seizures, and the most severely affected individual had myoclonic-astatic epilepsy (MAE). The pattern of inheritance was autosomal dominant. The large variation in generalized epilepsy phenotypes was not explained by acquired factors. Analysis of this large family and critical review of the literature led to the concept of a genetic epilepsy syndrome termed generalized epilepsy with febrile seizures plus (GEFS+). GEFS+ has a spectrum of phenotypes including febrile seizures, FS+ and the less common MAE. Recognition of GEFS+ explains the epilepsy phenotypes of previously poorly understood benign childhood generalized epilepsies. In individual patients the inherited nature of GEFS+ may be overlooked. Molecular genetic study of such large families should allow identification of genes relevant to febrile seizures and generalized epilepsies.
Adolescent↗
An Xp; Yq translocation causing a novel contiguous gene syndrome in brothers with generalized epilepsy, ichthyosis, and attention deficits.
PURPOSE: We describe two brothers with generalized epilepsy, attention deficits, congenital ichthyosis, and Leri-Weill dyschondrosteosis who harbor an unusual Xp; Yq translocation chromosome, resulting in a novel contiguous gene syndrome because of deletion of genes from the distal short arm of the X chromosome. METHODS: Physical examination, neuropsychologic testing, EEG, and neuroimaging studies were performed. Because of their unusual phenotype, karyotyping, fluorescence in situ hybridization, and further molecular analyses were carried out to refine the break points of the underlying unbalanced sex chromosome rearrangement. RESULTS: The subjects had generalized epilepsy, X-linked ichthyosis, Madelung deformities, mesomelia, normal intelligence, and attention deficits. The brothers' karyotype was unbalanced; they inherited a maternal derivative X chromosome. Deleted distal Xp genes included short-stature homeobox on the X chromosome (SHOX), aryl sulfatase E (ARSE), variably charged X-chromosome mRNA gene A (VCX-A), and steroid sulfatase (STS). The final karyotype was 46,Y,der(X)t(X; Y)(p22.3; q11.2).ish der(X) (DXZ1+, KAL+, STS-, SHOX-) mat. CONCLUSIONS: Loss of distal contiguous Xp genes resulted in a syndrome comprising bony deformities, ichthyosis, attention problems, and generalized epilepsy. Candidate epilepsy genes within the deleted segment, such as ASMT, a gene involved in the final synthesis of melatonin, are discussed. Cytogenetic analyses should be included in the clinical evaluation of patients with generalized epilepsy and complex phenotypes.
Adolescent↗
Generalized epilepsy with febrile seizures plus and severe myoclonic epilepsy in infancy: a case report of two Italian families.
"Generalized epilepsy with febrile seizures plus" (GEFS+) syndrome has been recently described. This term defines a heterogeneous group of generalized epilepsies observed in several members of large pedigree studies. The syndrome spectrum has been widened by including others forms of generalized epilepsy. We report two Italian families in which the fathers showed febrile seizure plus (FS+), and two sons had severe myoclonic epilepsy of infancy (SMEI). The clinical setting of each epileptic member of the family will be discussed, focusing on the relationship with the GEFS+ group, confirming its wide clinical spectrum. In fact, GEFS+ is different from most other epilepsy syndromes as it is defined not by a set of associated symptoms but by the genetic transmission of a predisposition to febrile convulsions and other seizures, with a variable expression in several members of the same pedigree, perhaps due to ionic channel dysfunction. SMEI could represent the most severe end of the spectrum.
Adult↗
Association of GABRG2 polymorphisms with idiopathic generalized epilepsy.
Missense mutations in the gamma2 subunit of gamma-aminobutyric acid (GABA) receptor gene have recently been described in families with idiopathic generalized epilepsies. This study aimed to evaluate whether polymorphisms of the gamma2 subunit of the GABA receptor gene are associated with idiopathic generalized epilepsies. A total of 77 children with idiopathic generalized epilepsies and 83 normal control subjects were included in the study. Polymerase chain reaction was used to identify the C/T and A/G polymorphisms of the gamma2 subunit of the GABA receptor gene on chromosome 5q33. Genotypes and allelic frequencies in both groups were compared. The gamma2 subunit of the GABA receptor (nucleotide position 3145 in intron G-> A) gene in both groups was not significantly different. In contrast, the gamma2 subunit of GABA receptor (SNP211037)-C allele frequency in patients with idiopathic generalized epilepsies was significantly higher than that in healthy control subjects (P = 0.002). The odds ratio for developing idiopathic generalized epilepsies in individuals with the gamma2 subunit of the GABA receptor (SNP211037)-C/C genotype was 3.61 compared with individuals with the gamma2 subunit of the GABA receptor (SNP211037)-T/T genotype. These data suggest that the gamma2 subunit of the GABA receptor gene might be one of the susceptibility factors for idiopathic generalized epilepsies.
Adolescent↗
Localization of idiopathic generalized epilepsy on chromosome 6p in families of juvenile myoclonic epilepsy patients.
Juvenile myoclonic epilepsy (JME) is a distinct subform of idiopathic generalized epilepsy of adolescence. Linkage studies with Bf and serologic HLA markers in families of JME patients have shown a tight linkage on chromosome 6. We present a linkage analysis with HLA-DQ restriction fragment length polymorphisms on more extended families, paying particular attention to the epilepsy type of the affected family members. We studied 21 families of JME patients with a total of 143 family members and obtained a highest logarithm of the odds (lod) score of 3.9 (theta m = 0.01, theta f = 0.01) assuming a dominant mode of inheritance and 70% penetrance when family members with JME, absence epilepsy, or epilepsy with generalized tonic-clonic seizures (GTCS) were considered as affected. When we also classified clinically normal family members with generalized spike-wave discharges in the EEG as "affected," the maximum lod score was 4.1 (theta m = 0.01, theta f = 0.3) under a dominant mode of inheritance and 90% penetrance. These findings support the conclusion that a gene locus for a group of idiopathic generalized epilepsies (JME, epilepsy with absences, and epilepsy with GTCS) maps to chromosome 6p.
Chromosomes, Human, Pair 6↗
Epilepsy in offspring of whom both parents have idiopathic generalized epilepsy: biparental inheritance.
BACKGROUND: Little is known about offspring of parents who both have idiopathic generalized epilepsy (IGE). This is of importance for understanding the complex genetic architecture of IGE. METHODS: Families in whom both parents had proven IGE were ascertained through a multiplex families database. Clinical information including EEG recordings and detailed pedigrees was obtained. RESULTS: In family I, the mother had juvenile myoclonic epilepsy (JME), and the father had IGE. One daughter had Lennox-Gastaut syndrome, and the other had unclassified epilepsy. In family II, the mother had JME, and the father had IGE. Two of three sons had an identical clinical picture of clinical picture of childhood absence epilepsy (CAE), but with fast polyspike-wave discharges on EEG. CONCLUSIONS: The clinical phenotype of affected offspring suggested that their epilepsy could be due to the combination of a putative "double dose" of genes from both sides of the family. In such families, as epilepsy genes could be inherited from both parents, a high risk of epilepsy in the offspring could be expected.
Adult↗
[Functional imaging in idiopathic generalized epilepsy].
Positron emission tomography has offered the possibility to investigate the pathophysiology of idiopathic generalized epilepsies. Absence epilepsies demonstrate normal cerebral glucose metabolism and benzodiazepine receptor density. Conversely, juvenile myoclonic epilepsies are associated with frontal hypometabolism, which aggravates during a working memory task. Typical 3 Hz spike and wave discharges lead to a diffuse hypermetabolism. The latter resembles that observed during GAERS rats absences, and clearly differs from the hypometabolism encountered in partial epilepsies associated with generalized spike and wave discharges. Overall, functional imaging data provide further evidence of syndromic specificities in idiopathic generalized epilepsies.
Animals↗
Telencephalic theory of generalized epilepsy: observations in split-brain patients.
The anatomical structures involved in the origin and spread of generalized seizures in humans have not been fully elucidated. Cortical, centrencephalic, and corticoreticular theories have been proposed to explain the clinical and electroencephalographic findings in patients with primary, generalized epilepsy or secondarily generalized seizures. Our observations in patients undergoing forebrain commissurotomy for intractable, generalized seizures lead us to propose a telencephalic theory of generalized epilepsy. This theory stresses the importance of the cerebral cortex as the site of origin of seizure discharge and the function of the forebrain commissures in the rapid propagation and bilateral synchronization of such discharge. These observations plus a review of the data generated from animal models of epilepsy are presented as evidence for such a theory. Although none of our patients had classical petit mal epilepsy, our findings suggest a secondary role of the brain stem reticular formation in generalized seizures and may be cogent to the discussion of primary, generalized epilepsy.
Adolescent↗
Visual working memory in primary generalized epilepsy: an 18FDG-PET study.
It is generally believed that patients with primary generalized epilepsy have normal cognition and neuroimaging studies. We have previously shown that patients with juvenile myoclonic epilepsy (JME) have impaired visual working memory. In this study we examined relative regional changes in 18FDG uptake during a visual working memory paradigm in patients with JME. At rest, there were regional decreases in relative glucose uptake compared to controls. Unlike control subjects, increased activity in the dorsolateral prefrontal cortex was not found during the working memory task. Other regions with increased uptake in controls, such as premotor cortex and basal frontal cortex, also showed no increases, whereas medical temporal structures appeared to play a role in JME but not in control subjects' task performance. The data suggest that JME, a type of primary generalized epilepsy, may suffer from cortical disorganization that affects both the epileptogenic potential and frontal lobe cognitive functioning.
Adult↗
Entorhinal cortex MRI assessment in temporal, extratemporal, and idiopathic generalized epilepsy.
PURPOSE: We previously showed a reduction in the volume of the entorhinal cortex (EC) ipsilateral to the seizure focus in patients with intractable temporal lobe epilepsy (TLE). The purpose of this study was to examine the specificity of EC atrophy in epilepsy. METHODS: We performed volumetric measurement of the EC on high-resolution magnetic resonance imaging (MRI) in patients with TLE (n = 70), extratemporal lobe epilepsy (ETE; n = 18), and idiopathic generalized epilepsy (IGE; n = 20). EC volumes of epilepsy patients were compared with those of 48 age- and sex-matched normal controls. Within the TLE group, 63 patients were selected prospectively with hippocampal atrophy ipsilateral to the seizure focus. The remaining seven patients were chosen retrospectively based on normal volumetric MRI of the hippocampus and amygdale, as well as normal histopathologic examination of the resected tissue. RESULTS: Compared with normal controls, EC volume was smaller ipsilateral but not contralateral to the seizure focus in patients with TLE (p < 0.001). No difference in the EC volumes ipsilateral and contralateral to the seizure focus was seen in patients with ETE and IGE compared with normal controls. The individual analysis showed that the EC was atrophic in 73% of TLE patients with hippocampal atrophy. Three of the seven TLE patients with normal volumetric MRI of the hippocampus and amygdala and normal histopathologic examination had EC atrophy ipsilateral to the seizure focus. In no patient with ETE or IGE was the EC found to be atrophic. CONCLUSIONS: EC atrophy ipsilateral to the seizure focus appears to be specific to mesial temporal lobe structural damage associated with TLE.
Adolescent↗
Tiagabine-induced absence status in idiopathic generalized epilepsy.
Several medications such as baclofen, amitriptyline and even antiepileptic drugs such as carbamazepine or vigabatrin are known to induce absence status epilepticus in patients with generalized epilepsies. Tiagabine (TGB) is effective in patients with focal epilepsies. However, TGB has also been reported to induce non-convulsive status epilepticus in several patients with focal epilepsies and in one patient with juvenile myoclonic epilepsy. In animal models of generalized epilepsy, TGB induces absence status with 3-5 Hz spike-wave complexes. We describe a 32-year-old patient with absence epilepsy and primary generalized tonic-clonic seizures since 11 years of age, who developed her first absence status epilepticus while treated with 45 mg of TGB daily. Administration of lorazepam and immediate reduction in TGB dosage was followed by complete clinical and electroencephalographic remission. This case demonstrates that TGB can induce typical absence status epilepticus in a patient with primary generalized epilepsy.
Adult↗
Idiopathic generalized epilepsy presenting with hemiconvulsive seizures.
PURPOSE: Unilateral seizures, or hemiconvulsive attacks, are motor seizures with tonic and/or clonic phenomena that involve only one side of the body. METHODS: We describe three adolescents who presented with hemiconvulsive seizures and were found to have 3-cps generalized spike-and-wave discharges on ictal and/or interictal EEG. All had normal neuroimaging studies. Two patients had been previously treated with carbamazepine, which led to a partial response in one patient. RESULTS: All three patients, however, are now seizure free on either sodium valproate or a combination of sodium valproate and lamotrigine. We believe the electroclinical diagnosis is that of idiopathic generalized epilepsy. CONCLUSIONS: Idiopathic generalized epilepsy presenting with hemiconvulsive seizures has not, to our knowledge, been previously described. However, the correct diagnosis of an idiopathic generalized seizure disorder, as opposed to a partial seizure disorder, has important treatment implications. The possible mechanism of hemiconvulsive seizures in idiopathic generalized epilepsy is discussed.
Adolescent↗
Seizure aggravation in idiopathic generalized epilepsies.
Seizures in the idiopathic generalized epilepsies (IGEs) usually remit completely with antiepileptic drugs (AEDs). Occasionally, however, they may be aggravated by AEDs. Before attributing exacerbation of seizures to an AED, alternative explanations need to be excluded. These include natural fluctuation of seizures, irregular compliance, maladjustment to the disease, comorbid illness, and development of tolerance. Aggravation may be due to a paradoxical reaction or drug-induced encephalopathy, sedative effects, or inappropriate use of a drug; and this need to be established, as it will guide management. An important caveat is that most data on aggravation of generalized seizures are based on anecdotal case reports or case series. Whether considering efficacy or aggravation, the interpretation of data from uncontrolled studies and case reports must be treated with caution. In practice, despite the fact that clear evidence is lacking, the possibility of seizure aggravation must be considered when treating people with IGEs. Predictive factors for seizure aggravation in a particular patient with a specific drug are yet to be fully defined. It is paramount to classify seizure type correctly in all patients. If this is not possible, a broad-spectrum AED should be used. Drugs that modulate Na+-channels and GABAergic drugs seem to be more prone to aggravating seizures, and therefore are best avoided in the initial management of IGE. Further studies are required to elucidate this phenomenon in full. It is interesting to speculate that paradoxical responses to AEDs may have pharmacogenetic value, serving as tools for a more precise and useful characterization of the epilepsies.
Acute Disease↗
[Autonomic asthenia syndrome in children with primary and secondary generalized epilepsy (clinico-encephalographic data)].
Clinical and physiological correlations were carried out on the basis of an analysis of clinical studies of vegetative dystonia (VD) and the general initial vegetative tone with determination of the mean percentage of the dominant activity, the dystonia ratio and the index of vegetative deviation devised for the first time and on the basis of studying interrelations between the synchronizing and desynchronizing systems according to the EEG readings. There were 107 children suffering from primary and secondary generalized epilepsy and 30 normal children of the same age. The patients with primary generalized epilepsy demonstrated the predominance of the activating influences of the reticular formation on brain bioelectric activity as compared to patients with secondary generalized epilepsy. This correlates with the data on the general initial vegetative tone and the clinical manifestations of VD. According to these data, the sympathetico-tonic manifestations were predominant in patients with primary generalized epilepsy, whereas the parasympathetic ones in those suffering from secondary generalized epilepsy.
Autonomic Nervous System↗
Primary (idiopathic) generalized epilepsy and underlying mechanisms.
Primary Generalized Epilepsy (PGE) has been more hotly debated over the past decades than other forms of epileptic seizure disorder. The sudden synchronous appearance of bilateral spikes and spike-waves (mainly with myoclonus resp. absence) used to perplex the earliest generation of electroencephalographers, and the enigmatic genesis of these discharges (and seizures) has not ceased to fascinate the investigators of this phenomenon. A "centrencephalic" concept with paroxysmal discharges arising from thalamic structures and "projecting" to the cortex was championed for many years and eventually laid aside. More recently, the role of the thalamic level has been re-emphasized, mainly on the basis of experimental work. In this article, the bulk of experimental work is critically reviewed: the simian model (Papio papio), the feline, and the rodent models (Wistar rat, tottering mouse). Stress is being laid on fundamental differences between all of these models and human PGE. EEG evidence indicates a superior frontal origin of bilateral-synchronous spikes and spike-waves; depth EEG recordings in patients have failed to demonstrate primary thalamic spike generation. The heart of the matter in PGE appears to be the mechanism underlying paroxysmal discharges; above all the role of arousal. It is not awakening from sleep but the ensuing period that is critical in its epileptogenic thrust caused by alternating periods of return to drowsiness and arousing stimuli. This biphasic process gradually escalates EEG bursts to myoclonus (or absences) and possibly to a generalized tonic-clonic convulsion. Most conducive to this crescendo is the state of tiredness following a night of poor sleep. Bilateral synchrony is not precise and small time differences exist. The line between primary and secondary bilateral synchrony (with a primary cortical focus) can become blurred. Genetic predisposition to generalized paroxysms must always be considered, even in the face of a primary focus with secondary bilateral synchrony. Photosensitivity is a second paroxysm-inducing mechanism in PGE; it is much less common than the abnormal arousal ("dyshormia"); both mechanisms can be present in the same patient. Therapy and prevention of seizures in PGE are finally discussed. The concept of abnormal arousal mechanisms can be put into practice in order to prevent seizures: avoidance of sleepless nights, not always an easy task in adolescents and young adults.
Animals↗
Familial clustering of seizure types within the idiopathic generalized epilepsies.
OBJECTIVE: To examine the genetic relationships among epilepsies with different seizure types--myoclonic, absence, and generalized tonic-clonic--within the idiopathic generalized epilepsies (IGEs). BACKGROUND: Careful phenotype definition in the epilepsies may allow division into groups that share susceptibility genes. Examination of seizure type, a phenotypic characteristic less complex than IGE syndrome, may help to define more homogeneous subgroups. METHODS: Using the approach that found evidence of distinct genetic effects on myoclonic vs absence seizures in families from the Epilepsy Family Study of Columbia University, the authors examined an independent sample of families from Australia and Israel. They also examined the familial clustering of generalized tonic-clonic seizures (GTCs) within the IGEs in two combined data sets. Families were defined as concordant if all affected members had the same type of seizure or IGE syndrome, as appropriate for the analysis performed. RESULTS: The proportion of families concordant for myoclonic vs absence seizures was greater than expected by chance in the Australian families. In addition, GTCs clustered in families with IGEs to a degree greater than expected by chance. CONCLUSIONS: These results provide additional evidence for distinct genetic effects on myoclonic vs absence seizures in an independent set of families and suggest that there is a genetic influence on the occurrence of generalized tonic-clonic seizures within the idiopathic generalized epilepsies.
Australia↗