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Mutations in the EFHC1 gene have been reported in six juvenile myoclonic epilepsy (JME) families from Mexico and Belize. In this study, we screened 27 unrelated JME Italian families for mutations in the EFHC1 gene.Twenty-seven families (86 affected individuals, 52 women) with at least two affected members with JME were selected. DNA was isolated from peripheral blood lymphocytes by standard methods and each exon of the EFHC1 gene was amplified and sequenced using intronic primers.Two heterozygous mutations were identified in three unrelated families. One (R353 W) was a novel missense mutation, while the F229 L mutation was previously described (say which on of the two occurred in two families). Both mutations cosegregated with the disease. In a fourth family, the variant 545G-->A (resulting in the amino acid substitution R182 H) cosegregated with JME.The results of our study extend the distribution of EFHC1 mutations to the white population and confirm the high level of genetic heterogeneity associated with JME.

OBJECTIVES: Mutations in the EFHC1 gene have been reported in six juvenile myoclonic epilepsy (JME) families from Mexico and Belize. In this study, we screened 27 unrelated JME Italian families for mutations in the EFHC1 gene. MATERIALS AND METHODS: Twenty-seven families (86 affected individuals, 52 women) with at least two affected members with JME were selected. DNA was isolated from peripheral blood lymphocytes by standard methods and each exon of the EFHC1 gene was amplified and sequenced using intronic primers. RESULTS: Two heterozygous mutations were identified in three unrelated families. One (R353 W) was a novel missense mutation, while the F229 L mutation was previously described (say which on of the two occurred in two families). Both mutations cosegregated with the disease. In a fourth family, the variant 545G-->A (resulting in the amino acid substitution R182 H) cosegregated with JME. CONCLUSIONS: The results of our study extend the distribution of EFHC1 mutations to the white population and confirm the high level of genetic heterogeneity associated with JME.

Background: Dysfunction of γ-aminobutyric acid (GABA) (B) receptors has been implicated in the pathogenesis of temporal lobe epilepsy (TLE).Objective: To evaluate the genetic contribution of cloned human GABA(B) receptors to TLE.Methods: The authors genotyped 141 patients (78 women and 63 men; mean age = 49.1 ± 18.0 years) with nonlesional TLE and 372 age- and sex-matched normal individuals for the known polymorphism G1465A in the human GABA(B) receptor 1 [GABA(B[1])] gene.Results: There was a highly significant overrepresentation of the G1465A heterozygote in patients with TLE compared with controls. The A/G genotype was found in 17% of the 141 patients with TLE and in only 0.5% of the 372 controls (p < 0.0001). The authors also found that patients carrying the A allele had a significantly higher risk (p = 0.003, OR = 6.47, 95% CI = 2.02 to 20.76) of developing drug-resistant TLE. Furthermore, the age at onset of seizures tended to be lower in patients with A/G genotype, but the difference was not significant.Conclusions: The results of this study indicate that the GABA(B[1]) polymorphism (G1465A) confers a highly increased susceptibility to TLE. Moreover, it seems to influence the severity of this common epileptic disorder.