Aetiology of idiopathic generalised epilepsies

The idiopathic epilepsies are:

• generalised tonic-clonic epilepsy
• juvenile myoclonic epilepsy
• childhood absence epilepsy
• juvenile absence epilepsy

These idiopathic generalised epilepsy syndromes are common, accounting for 60% of all cases of epilepsy.

They are complex genetic diseases with a multi-gene mode of inheritance.

The genetic contribution to the idiopathic generalised epilepsies can be understood from the following statistics:

• the prevelence of idiopathic generalised epilepsy in the community is 0.4%
• the risk of epilepsy in the first degree relative of a patient with one of these syndromes is 8%
• the concordance for dizygotic twins is 24%
• the concordance for monozygotic twins is 65%

To date no genes for idiopathic generalised epilepsy have been identified.