A splice-site mutation in GABRG2 associated with childhood absence epilepsy and febrile convulsions

Arch Neurol. 2002 Jul;59(7):1137-41. doi: 10.1001/archneur.59.7.1137.


Context: Missense mutations in the GABRG2 gene, which encodes the gamma 2 subunit of central nervous gamma-aminobutyric acid (GABA)(A) receptors, have recently been described in 2 families with idiopathic epilepsy. In one of these families, the affected individuals predominantly exhibited childhood absence epilepsy and febrile convulsions.

Objective: To assess the role of GABRG2 in the genetic predisposition to idiopathic absence epilepsies.

Design: The GABRG2 gene was screened by single-strand conformation analysis for mutations. Furthermore, a population-based association study assessing a common exon 5 polymorphism (C588T) was carried out.

Patients: The sample was composed of 135 patients with idiopathic absence epilepsy and 154 unrelated and ethnically matched controls.

Results: A point mutation (IVS6 + 2T-->G) leading to a splice-donor site mutation in intron 6 was found. The mutation, which is predicted to lead to a nonfunctional protein, cosegregates with the disease status in a family with childhood absence epilepsy and febrile convulsions. The association study did not find any significant differences in the allele and genotype frequencies of the common exon 5 polymorphism (C588T) between patients with idiopathic absence epilepsy and controls (P>.35).

Conclusions: Our study identified a splice-donor-site mutation that was probably causing a nonfunctional GABRG2 subunit. This mutation occurred in heterozygosity in the affected members of a single nuclear family, exhibiting a phenotypic spectrum of childhood absence epilepsy and febrile convulsions. The GABRG2 gene seems to confer a rare rather than a frequent major susceptibility effect to common idiopathic absence epilepsy syndromes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Alleles
  • Epilepsy, Absence / genetics*
  • Epilepsy, Absence / metabolism
  • Exons
  • Female
  • Genotype
  • Humans
  • Male
  • Mutation, Missense*
  • Polymorphism, Genetic
  • Receptors, GABA-A / genetics*
  • Reverse Transcriptase Polymerase Chain Reaction
  • Seizures, Febrile / genetics*
  • Seizures, Febrile / metabolism


  • Receptors, GABA-A