Genetic epilepsies are classified according to the mechanism of inheritance in three major groups: 1) Mendelian idiopathic epilepsies; 2) Non-Mendelian or “complex” epilepsies; and 3) Chromosomal disorders. Mendelian epilepsies include the autosomal dominant, benign familial neonatal and infantile convulsions, nocturnal frontal lobe epilepsy, and generalized epilepsy with febrile seizures. Non-Mendelian “complex” idiopathic epilepsies include juvenile myoclonic, febrile convulsions, childhood absence, juvenile absence, and benign epilepsy with centrotemporal spikes. Among symptomatic epilepsies, progressive myoclonic types account for 1% of childhood epilepsies. These are Mendelian (Unverricht-Lundborg, neuronal ceroid lipofuscinoses, and Lafora disease), and Non-Mendelian “complex” progressive myoclonic, associated with mitochondrial disorders. New classifications based on molecular genetics require identification of common DNA sequence variations between individuals. The authors predict that DNA from a buccal swab will be analyzed for common mutations in ion channel genes, and an antiepilepsy drug designed for the specific electrophysiological dysfunction. With the precise molecular diagnosis of the future, the EEG could become a redundant investigation. 
COMMENT. The epilepsies are heterogeneous in manifestations and causes. A genetic etiology may be present in more than 40% of childhood patients.