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.

The Effects of Topiramate on Epileptiform Discharges Induced by Mg(2+)- Free Medium and 4-Aminopyridine in Hippocampal Slices of Immature Rats / 대한소아신경학회지

PURPOSE: Topiramate(TPM), one of the newest antiepileptic drugs, has been prescribed not only to refractory partial seizures but to generalized tonic-clonic seizures. However, its action mechanisms are not well understood and the optimal dose of antiepileptic efficacy in animal seizure models is not determined yet. In order to elucidate the action mechanisms and the optimal concentration of TPM that suppresses epileptic discharges, we observed ictal and interictal discharges from immature rat hippocampal slices in Mg(2+)-free, and 4-aminopyridine(AP) added artificial CSF with various TPM concentrations. METHODS: We divided Sprague-Dawley rats of 19 to 23 days old into 5 groups; namely, a control group(n=12) and 4 TPM groups according to the concentration of TPM, 6 (n=11), 20(n=7), 60(n=10), and 200(n=14) micrometer. The rats were anesthetized and their brains were taken, and soaked in artificial CSF(NaCl 125 mM; KCl 2.5 mM; NaH2PO4 2 mM; MgSO4 1.25 mM; NaHCO3 25 mM; CaCl2 2 mM, Glucose 10 mM, and pH 7.3-7.4). Then the brains were cut into 400 micrometer hippocampal slices by a vibratome. The slices of the control group were soaked in 200 micrometer 4-AP added Mg(2+)-free medium for 1 hour, and then extracellular recordings were performed in the hippocampal CA1 pyramidal region. The slices of TPM groups were soaked in solutions containing 6, 20, 60, 200 micrometer TPM, and then extracellular recordings were performed. RESULTS: Interictal discharges were observed in the control group and 6, 20 micrometer groups but the frequency decreased as the concentration of TPM increased:90% in 60 micrometer group, and 35.7% in 200 micrometer group. And the amplitude of TPM groups was much smaller than that of the control group. The latency to the first interictal discharge after 4-AP addition was 52.7+/-7.5 sec in the control group, 290.2+/-78 sec in 60 micrometer group, and 568+/-113.1 sec in 200 micrometer group. Duration of the interictal discharge was 64.6+/-10.3 sec in the control group, but was prolonged to 141+/-38.1 sec in 60 micrometer group(P<0.05). Ictal discharges were observed in all of the control and 6 micrometer groups, but the frequency decreased as the concentration of TPM increased:55.6% in 60 micrometer, and 28.6% in 200 micrometer groups. The amplitude of the TPM groups was much smaller than that of the control group. The latency to ictal discharges after 4-AP addition was 141+/-15.2 sec in the control group, but increased as the concentration of TPM increased:431.8+/-57.4 sec in 60 micrometer, and 627.8+/-143.5 sec in 200 micrometer group(P<0.05). The duration of ictal discharges was 1,534.7+/-97.9 sec in the control group, but decreased as the concentration of TPM increased, the shortest in 60 micrometer group, 155.2+/-65.5 sec(P<0.05). Status epilepticus was seen in 58.3% of the control and 27.2% of 6 microM groups. CONCLUSION: TPM suppresses the frequency, latency, and duration of epileptiform discharges induced by Mg(2+)-free, and 4-AP added artificial CSF in immature rat hippocampal slices, starting from 20 micrometer and reaching the maximal effect at over 60 micrometereter. This finding is presumably due to TPM enhancing of GABA receptor currents and/or K+ channel conductance in response to TPM.

A Case of SRY Positive 46,XX Male / 대한소아내분비학회지

46,XX male is a rare abnormality of sex determination with an incidence of 1 in 20,000 male neonates. The clinical manifestations of 46,XX males are usually hypogonadism, gynecomastia, azoospermia, and hyalinations of seminiferous tubules, with altered hormonal levels at puberty. Less frequently, some sexual ambiguities are found, always with sterility owing to reduced testicular development. The origin of male phenotype in 46,XX male could be the results of at least three different mechanisms:translocations of Y sequence, including the SRY gene, to an X chromosome or to an autosome(about 90% of cases); a mutation in a yet unknown X-linked or autosomal gene in the testis-determinating pathway, and cryptic Y chromosome mosacism. We experienced a case of SRY-positive 46,XX male in a 21-year-old man with small testes. (J Korean Soc Pediatr Endocrinol 2003;8:184-188)

A Case of SRY Positive 46,XX Male / 대한소아내분비학회지

46,XX male is a rare abnormality of sex determination with an incidence of 1 in 20,000 male neonates. The clinical manifestations of 46,XX males are usually hypogonadism, gynecomastia, azoospermia, and hyalinations of seminiferous tubules, with altered hormonal levels at puberty. Less frequently, some sexual ambiguities are found, always with sterility owing to reduced testicular development. The origin of male phenotype in 46,XX male could be the results of at least three different mechanisms:translocations of Y sequence, including the SRY gene, to an X chromosome or to an autosome(about 90% of cases); a mutation in a yet unknown X-linked or autosomal gene in the testis-determinating pathway, and cryptic Y chromosome mosacism. We experienced a case of SRY-positive 46,XX male in a 21-year-old man with small testes. (J Korean Soc Pediatr Endocrinol 2003;8:184-188)