Epilepsias generalizadas idiopáticas / Idiopathic generalized epilepsies

Resumen Las epilepsias generalizadas idiopáticas (EGI) son un grupo de epilepsias generalizadas edad de pendientes, subgrupo de las Epilepsias genéticas generalizadas(EGG), con hallazgos electro-clínicos característicos y herencia poligénica. Las EGI inclu yen las cuatro epilepsias generalizadas clásicas más comunes de las EGG: la epilepsia de ausencias de la infancia (EAI), epilepsia de ausencias juveniles (EAJ), epilepsia mioclónica juvenil (EMJ) y la epilepsia con crisis tónico clónicas generalizadas. Clínicamente caracterizadas por la presencia de una o una com binación de crisis de ausencias, mioclonías, tónica-clónicas omioclónica-tónica-clónicas con patrón elec troencefalográfico de punta onda lenta de 2.5 a 6cps y activación con la hiperventilación y fotoestimula ción, Sobresalen de las EGG por compartir atributos particulares como el buen pronóstico con control frecuente de las crisis, la no evolución a encefalopa tías epilépticas, frecuente superposición clínica entre las tres primeras, pudiendo evolucionar entre ellas; la probabilidad y edad de remisión varía en cada una.Más del 80% se controlan adecuadamente con medicamentos anticrisis de amplio espectro como el ácido valproico y pueden empeorar con bloqueadores de sodio o gabaérgicos. Si bien los pacientes son previamente sanos con neurodesarrollo normal, frecuentemente se asocian con trastornos del ánimo, déficit de atención e hiperactividad (TDAH) y problemas del aprendizaje pero no presentan déficit cognitivo. El reconocimiento de este grupo de EGI es importan te para el uso adecuado del recurso, evitando estudios innecesarios, adecuada orientación del pronóstico y un tratamiento óptimo.

Abstract Idiopathic generalized epilepsies (IGE) is a group of epilepsies age-dependent, a subgroup of EGG genetic generalized epilepsies, with electro-clinical features and polygenic inheritance. Four syndromes comprising the IGEs: childhood absence epilepsy (CAD), juvenile absence epilepsy (JAE), juvenile myoclonic epilepsy (JME), and generalized tonic-clonic seizures epilepsy. Clinically characterized by the presence of one or a combination of absence seizures, myoclonus, tonic-clonic, or myoclonic-tonic-clonic with common electroencephalographic pat terns of 2.5-5.5 Hz generalized spike-wave and activated by hyperventilation or photic stimulation. They generally have a good prognosis for seizure control, not evolve to an epileptic encephalopathy. Frequent clinical overlap between the first three, being able to evolve between them; the probability and age of remission varies in each one. About 80% responding to broad-spectrum anti-seizure drugs such as valproic acid, may worsen with sodium or GABAergic blockers. Development is typically normal; however, they are frequently associated with mood disorders, attention-deficit/hyperactivity disorder (ADHD), and learning dis abilities, but do not have cognitive deficits. The recognition of this group of EGI is important for the adequate use of the resources, avoiding unnecessary studies, adequate orientation of the prognosis and an optimal treatment.

Genetic progress of childhood absence epilepsy / 上海交通大学学报（医学版）

Childhood absence epilepsy (CAE) is an important kind of epileptic syndrome of genetic generalized epilepsies (GGEs) with prevalence of 5.8/100 000-7.1/100 000.The genetic mechanism of CAE is always the hotspot of research.Susceptibility genes including calcium channel and γ-aminobutyric acid receptor as well as copy number variations (CNVs) have been found.However,those mechanisms cannot explain all the situations since the genetic content of CAE is rather complicated.Nowadays,with new susceptibility genes and genetic mechanisms coming to light,researchers are supposed to study this problem from the point of associated epileptic syndromes.In this review,the genetic features,probable mechanisms of CAE and therapeutic drugs were summarized.

Genetic progress of childhood absence epilepsy / 上海交通大学学报（医学版）

Childhood absence epilepsy (CAE) is an important kind of epileptic syndrome of genetic generalized epilepsies (GGEs) with prevalence of 5.8/100 000-7.1/100 000. The genetic mechanism of CAE is always the hotspot of research. Susceptibility genes including calcium channel and γ-aminobutyric acid receptor as well as copy number variations (CNVs) have been found. However, those mechanisms cannot explain all the situations since the genetic content of CAE is rather complicated. Nowadays, with new susceptibility genes and genetic mechanisms coming to light, researchers are supposed to study this problem from the point of associated epileptic syndromes. In this review, the genetic features, probable mechanisms of CAE and therapeutic drugs were summarized.

Single Nucleotide Polymorphisms of GABRG2 in Idiopathic Generalized Epilepsies(IGEs) / 대한소아신경학회지

PURPOSE: Mutations in gamma-aminobutyric acid(GABA) A receptor gamma2 subunit gene (GABRG2) were independently identified in families of generalized epilepsy with febrile seizures plus(GEFS+) and families of absence epilepsy and febrile seizures(FSs). The present study assessed the role of GABRG2 gene in idiopathic generalized epilepsies(IGEs) of Korean population. METHODS: Twenty-three IGEs and 94 healthy control subjects were selected through a collaborative study of Catholic Child Neurology Research Group. The SNP211037 of GABRG2 were screened by DHPLC. DNA fragments showing variant chromatograms were subsequently sequenced. Genotypes and allelic frequencies for GABRG2 gene polymorphism in three groups were compared. RESULTS: Genotypes and allelic frequencies of the gamma2 subunit of the GABA receptor gene(SNP211037) in both groups were not significantly different. The most common genotypes for GABRG2(SNP211037) gene in both groups were T/C heterozygote. The allele C and T frequencies for GABRG2(SNP211037) in the IGEs group were 45.7% and 54.3%, respectively and in healthy control group, 42.6% and 57.4%, respectively. The number of individuals with the GABRG2 (SNP211037)-C/C genotype in the IGEs group was greater compared with that in the healthy control group(21.7% versus 12.8%). The odds ratio for developing IGEs in individuals with the GABRG2 (SNP211037)-CC genotype was 1.65 compared with individuals with the GABRG2 (SNP211037)-T/T genotype, which was not significantly different. CONCLUSION: These data suggest that genomic variations of GABRG2 might not be one of the susceptibility factors for IGEs in the Korean population.

A reappraisal of secondary bilateral synchrony

A reappraisal was made with respect to a classical observation of the mode of instrumental phase reversals on inter-ictal EEG of seemingly bilateral synchronous spike-wave discharges in patients with either idiopathic generalized epilepsies (IGE) or symptomatic localization-related frontal lobe epilepsies (FLE). It was pointed out in the original observation by Tukel and Jasper that one phase reversal at midline or near the midline on the side of the parasagittal epileptogenic lesion designated as secondary bilateral synchrony (SBS) was found in patients with frontal lobe epilepsy (FLE), whereas a double phase reversal was found over the homologous frontal electrodes (F3 and F4) designated as primary bilateral synchrony (PBS) in patients with IGE. Twenty-three patients (IGE: 15, and FLE: 8) revealing bursts of seemingly bisynchronous spike-wave discharges in interictal EEGs were retrospectively studied. Discharge patterns were defined as stable phase reversal pattern if the site of phase-reversal was consistent, and as unstable pattern if the site of phase-reversal was not consistent but shifting in the same patient. Stable one phase-reversal pattern was found more frequently in FLE (50%) than in IGE patients (26.7%), and stable double phase-reversal pattern more frequently in the IGE (33.3%) than in the FLE group (12.5%). Notably, unstable pattern was found almost equally in both IGE and FLE patients (40% and 37.5%, respectively). Recognition of SBS or PBS in accordance with original observation was found not to clearly differentiate FLE from IGE in patients showing seemingly bisynchronous spike-wave complexes. The variability of instrumental phase-reversals can be accounted for by the fact that the localization of maxima of negative spike of the spike-and-wave complexes varies considerably.