Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0036572 (seizures)
 80,221 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The neurochemical basis of absence seizures and the mechanism of their suppression by valproate (VPA) are uncertain. We used positron emission tomography (PET) to determine whether an abnormality of [11C]flumazenil binding to benzodiazepine (BZD)-GABAA receptors exists in patients with childhood and juvenile absence epilepsy and to examine the effects of VPA on [11C]flumazenil binding. The regional cerebral volume of distribution (Vd) of [11C]flumazenil in patients not treated with VPA was not different from that in normal controls; Vd was lower in patients treated with VPA, and the number of receptors available for binding was significantly reduced in such patients as compared with normal controls. There was no evidence of a primary abnormality of the BZD-GABAA receptor in childhood and juvenile absence epilepsy (CAE/JAE), but the data suggest that treatment with VPA is associated with a reduction in [11C]flumazenil binding that may be relevant to its mode of action in CAE/JAE.
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PMID:Benzodiazepine-GABAA receptors in idiopathic generalized epilepsy measured with [11C]flumazenil and positron emission tomography. 782 Dec 67

To assess prognostic factors for absence epilepsy (AE), we analyzed data from 80 patients treated for childhood AE (CAE; n = 53) or juvenile AE (JAE; n = 27) in our epilepsy clinic between 1985 and 1992. All patients were classified according to the International Classification of Epileptic Syndromes which was proposed by the International League against Epilepsy in 1989. Patients were separated into two groups based on the course of disease under adequate treatment: Complete response group (CRG): disappearance of absence seizures (AS) or generalized tonic-clonic seizures (GTCS). Poor response group (PRG): persistence of AS and/or GTCS. Approximately 40% of both CAE and JAE patients had poor response. One parameter was associated with poor prognosis in CAE patients, the presence of polyspikes or polyspikes and waves during sleep. No statistical correlation was made for JAE patients. GTCS were frequent in JAE and GTCS occurrence in CAE patients was associated significantly with age at onset after 8 (p < 0.05). The fact that social and educational performance was poorer in the PRG of both types of AE underlines the importance of therapeutic response in patient rehabilitation.
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PMID:Prognostic factors for childhood and juvenile absence epilepsies. 913 27

Mutations in the gene encoding the alpha1A-calcium channel subunit play a causative role in the epileptogenesis of absence seizures in tottering mutant mice. The present family-based association and non-parametric linkage study tested the hypothesis that allelic variants of the homologous human gene (CACN1A4) confer susceptibility to common subtypes of idiopathic generalized epilepsy (IGE). An expressed polymorphic CAG trinucleotide repeat in the 3' end of the CACN1A4 gene was assessed in 70 families ascertained through members with either childhood (CAE) and juvenile absence epilepsy (JAE), or juvenile myoclonic epilepsy (JME). Our association analysis using the haplotype-based haplotype relative risk statistic provided no evidence for an allelic association of the CAG repeat polymorphism with either IGE, or CAE and JAE, or JME. We found no relation between the CAG repeat length and susceptibility neither to IGE, nor to CAE and JAE, nor to JME. Non-parametric linkage analysis revealed no evidence for linkage of IGE traits with the CACN1A4 locus in 42 families of patients with either CAE or JAE. A weak trend towards an excess of allele sharing (identity by descent) among family members affected by an IGE was obtained in 26 families of JME patients (Z[NPL] = 1.25 at theta = 0.000, p = 0.057). Taken together, we found no statistically significant evidence that genetic variants of the CACN1A4 gene play a causative role in the pathogenesis of common subtypes of IGE in humans.
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PMID:The gene encoding the alpha1A-voltage-dependent calcium channel (CACN1A4) is not a candidate for causing common subtypes of idiopathic generalized epilepsy. 947 43

Lamotrigine (LTG) is an anti-epileptic drug effective in partial seizures and generalized epilepsy. There is growing evidence of the usefulness of LTG in childhood (CAE) orjuvenile (JAE) absences resistant to previous treatment. In this study all patients were identified using strict diagnostic criteria and subdivided into two groups. (1) Eight patients affected by absence seizures resistant to valproic acid or ethosuximide, received LTG as an-add-on therapy, (2) seven patients affected by typical absence seizures not previously treated, received LTG monotherapy after the diagnosis. In the patients with resistant absence seizures, a full control of seizures was obtained. In five of them, after a mean period of 12.5 months, the previous anti-epileptic drugs were withdrawn leaving the patients on LTG monotherapy. In one patient, absences relapsed and valproic acid was therefore added again to LTG to regain control of the seizures. In six of the seven patients on LTG monotherapy after the diagnosis, a full control of seizures was obtained. In the seventh patient the drug was stopped due to a skin rash. In conclusion LTG appears to be effective in resistant absence seizures in combination with valproic acid. Moreover, our preliminary data suggest that lamotrigine might be used as monotherapy in typical absence seizures. The advantages and disadvantages of LTG monotherapy in this type of epilepsy are discussed.
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PMID:Lamotrigine in typical absence epilepsy. 1041 16

This study compared parent-based Child Behavior Checklist (CBCL) social competence scores of 90 children with complex partial seizures (CPS) and 62 with absence epilepsy (CAE) of average intelligence with scores of 91 healthy children. It also examined the role of seizure-related, cognitive, behavioral, linguistic, social communication, and demographic variables on these measures. When differences in cognitive, linguistic, and demographic variables were controlled for, the CPS and CAE groups had significantly lower scores in the school, but not in the social interaction and activities domains compared with the healthy control group. Among the patients, lower Full Scale IQ externalizing behaviors, disruptive disorders, minority status, and impaired social communication, but not seizure variables, predicted lower social competence scores. These findings demonstrate the importance of controlling for cognitive, behavioral, and demographic variables in social competence studies of children with CPS and CAE and the need to assess cognition and behavior when parents report school and social problems in these children.
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PMID:Social competence in pediatric epilepsy: insights into underlying mechanisms. 1571 Mar 8

The 2001 classification subcommittee of the International League Against Epilepsy (ILAE) proposed to 'group JME, juvenile absence epilepsy, and epilepsy with tonic clonic seizures only under the sole heading of idiopathic generalized epilepsies (IGE) with variable phenotype'. The implication is that juvenile myoclonic epilepsy (JME) does not exist as the sole phenotype of family members and that it should no longer be classified by itself or considered a distinct disease entity. Although recognized as a common form of epilepsy and presumed to be a lifelong trait, a long-term follow-up of JME has not been performed. To address these two issues, we studied 257 prospectively ascertained JME patients and encountered four groups: (i) classic JME (72%), (ii) CAE (childhood absence epilepsy) evolving to JME (18%), (iii) JME with adolescent absence (7%), and (iv) JME with astatic seizures (3%). We examined clinical and EEG phenotypes of family members and assessed clinical course over a mean of 11 +/- 6 years and as long as 52 years. Forty per cent of JME families had JME as their sole clinical phenotype. Amongst relatives of classic JME families, JME was most common (40%) followed by grand mal (GM) only (35%). In contrast, 66% of families with CAE evolving to JME expressed the various phenotypes of IGE in family members. Absence seizures were more common in family members of CAE evolving to JME than in those of classic JME families (P < 0.001). Female preponderance, maternal transmission and poor response to treatment further characterized CAE evolving to JME. Only 7% of those with CAE evolving to JME were seizure-free compared with 58% of those with classic JME (P < 0.001), 56% with JME plus adolescent pyknoleptic absence and 62% with JME plus astatic seizures. Long-term follow-up (1-40 years for classic JME; 5-52 years for CAE evolving to JME, 5-26 years for JME with adolescent absence and 3-18 years for JME with astatic seizures) indicates that all subsyndromes are chronic and perhaps lifelong. Seven chromosome loci, three epilepsy-causing mutations and two genes with single nucleotide polymorphisms (SNPs) associating with JME reported in literature provide further evidence for JME as a distinct group of diseases.
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PMID:Juvenile myoclonic epilepsy subsyndromes: family studies and long-term follow-up. 1652 Mar 31

Early onset of absence seizures (<3 years) is rare and usually associated with a poor cognitive prognosis. Familial cases have not been reported to date. We observed a family in which two out of three sibs showed early-onset absences and mild mental retardation. Linkage to the ECA1 locus, where one clinical subtype of CAE is mapped, was excluded by haplotype analysis. Direct sequencing of the candidate genes CLCN2 ,GABRG2 and CHRNA4 showed no mutations. We suggest the possibility of a specific epileptic syndrome with a putative AR inheritance. Further report of affected patients might allow a better classification.
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PMID:Familial occurrence of early-onset childhood absence epilepsy. 1726 50

Early-onset absence epilepsy refers to patients with absence seizures beginning before age 4 and comprises a heterogeneous group of epilepsies. Onset of absence seizures in the first year of life is very rare. We report a boy with absence seizures with onset at age 11 months, whose seizures increased in frequency after the introduction of valproic acid (VPA) treatment and substantially improved upon cessation of treatment. The mechanism of seizure worsening did not involve VPA toxicity, encephalopathy, Glut-1 deficiency or overdosage, and the reason for absence seizure aggravation remained unclear. The patient showed complete control of absence seizures with levetiracetam treatment and the course was benign, both in terms of seizure control and neuropsychological aspects. The similar overall electroclinical picture and outcome between children with early-onset absences and those with CAE support the view that these conditions are a continuum within the wide spectrum of IGE. [Published with video sequences].
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PMID:Early-onset absence epilepsy aggravated by valproic acid: a video-EEG report. 2416 39

In the recent years, several neurological syndromes related to defects of the glucose transporter type 1 (Glut1) have been descried. They include the glucose transporter deficiency syndrome (Glut1-DS) as the most severe form, the paroxysmal exertion-induced dyskinesia (PED), a form of spastic paraparesis (CSE) as well as the childhood (CAE) and the early-onset absence epilepsy (EOAE). Glut1, encoded by the gene SLC2A1, is the most relevant glucose transporter in the brain. All Glut1 syndromes respond well to a ketogenic diet (KD) and most of the patients show a rapid seizure control. Ketogenic Diet developed to an established treatment for other forms of pharmaco-resistant epilepsies. Since we were interested in the question if those patients might have an underlying Glut1 defect, we sequenced SLC2A1 in a cohort of 28 patients with different forms of pharmaco-resistant epilepsies responding well to a KD. Unfortunately, we could not detect any mutations in SLC2A1. The exact action mechanisms of KD in pharmaco-resistant epilepsy are not well understood, but bypassing the Glut1 transporter seems not to play an important role.
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PMID:Do Glut1 (glucose transporter type 1) defects exist in epilepsy patients responding to a ketogenic diet? 2608 84

This article reviews the contribution of pharmacologically induced acute and chronic animal models to our understanding of epilepsies featuring non-convulsive generalized seizures, the typical and atypical absence seizures. Typical absences comprise about 5% of all epilepsies regardless of age and the atypical ones are even more common. Although absence epilepsy was thought to be relatively benign, children with childhood epilepsy (CAE) turn out to have a high rate of pretreatment attention deficits that persist despite seizure freedom. The phenomenon of the absence seizure has long attracted research interest because of the clear temporal relationship of the conspicuous EEG rhythm of 3 Hz generalized spike and wave discharges (GSWD) and the parallel transient "loss of consciousness" characterizing these seizures which is time-locked with the GSWD. Indeed, clinical epileptologists, basic scientists and neurophysiologists have long recognized in GSWD a unique electrographic and behavioral marker of the genetic predisposition to most types of epilepsy. Interestingly, the subject is still controversial since it has recently been proposed that both classification terms of CAE currently in use: idiopathic and primary generalized, be abandoned - a point of debate. Both issues - underlying mechanisms and focal origin of absence seizures - may be further enlightened by observations in valid animal models.
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PMID:Acute and chronic pharmacological models of generalized absence seizures. 2634 23


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