[Molecular defects may cause epilepsy. New discoveries can provide better possibilities for directional diagnostics...

Specific defects in neuronal ion channel proteins have recently been identified in some forms of hereditary epilepsy. A deletion of 300 amino acids from the COOH terminal of the K+ channel reduces the electrical stability of the neuron in subjects with benign familial neonatal seizures. Defects in the protein subunits of the Na+ channel may prolong neuronal depolarization in children with generalized epilepsy with febrile convulsions. A point mutation in one of the ACh receptor subunits may reduce the function of inhibitory interneurons in subjects with autosomal dominant nocturnal frontal lobe epilepsy. Finally, several different defects in the Ca2+ channel amino acid sequence have been identified in various types of epilepsy in mice in which symptoms and EEG show similarities to those in human petit mal. This remarkable progress in the precise localization of ion channel defects in epilepsy provides a novel basis for the development of more differentiated diagnosis and pharmacological therapy.