Exclusion of linkage between idiopathic generalized epilepsies and the GABAA receptor ?1 and ?2 subunit gene cluster on chromosome 5

Hereditary factors play a major role in the etiology of idiopathic generalized epilepsies (IGEs). The pivotal function of ionotropic ?-aminobutyric acid type A receptors (GABRs) in inhibitory neurotransmission in the mammalian central nervous system suggests that they may be involved in epileptogenesis and genetic predisposition to IGEs. Dinucleotide repeat polymorphisms associated with the human {GABAA} receptor ?1 (GABRA1) and ?2 subunit (GABRG2) gene cluster on chromosome 5q32-q35 offer the opportunity to test whether these candidate genes confer susceptibility to IGEs. Our linkage analyses in 63 families ascertained through {IGE} patients with either juvenile myoclonic epilepsy, juvenile absence epilepsy or childhood absence epilepsy do not support the hypothesis that variants within the {GABRA1} and {GABRG2} gene cluster contribute a frequent major gene effect to the expression of the common familial IGEs