Possible association between childhood absence epilepsy and the gene encoding GABRB3

Background: Childhood Absence Epilepsy (CAE) is considered to have a predominantly, perhaps exclusively, genetic background. To date, genes responsible for susceptibility to CAE have not been identified. The object of the present study was to test association between CAE and the genes encoding the γ-aminobutyric acid (GABA) type-A receptor subunits α5 (GABRA5) and β3 (GABRB3) located on the long arm of chromosome 15 (15q11–q13). Methods: A family-based candidate gene approach was applied: 50 Austrian nuclear families ascertained for the presence of an affected child were investigated. GABRA5 and GABRB3 subunit genes were genotyped using DNA gained from peripheral blood samples by Polymerase Chain Reactions (PCR). Genetic association was tested using a Monte Carlo Version of the multi-allele Transmission-Disequilibrium Test (TDT). Results: The TDT displayed significant overall association with GABRB3 (p = .0118). Conclusions: The present data suggest that the tested polymorphism may be either directly involved in the etiology of CAE or in linkage disequilibrium with disease-predisposing sites.