Epilepsy, which affects 0.5% of the population, is the most common serious neurological illness of children and young people. Although individuals with epilepsy may live relatively normal lives, one-third have intractable seizures with major social, psychological, physical and cognitive sequelae. Most epilepsy presenting in childhood has a direct genetic cause. Here we propose to refine the clinical characteristics of emerging types of epilepsy, identify new genetic epilepsy syndromes and find the genes causing these. We will study families with multiple individuals with epilepsy as well as children with severe types of epilepsy. All family members are interviewed to characterise their epilepsy, a family tree constructed and a DNA sample taken. New epilepsy syndromes will be identified and described. Molecular genetic techniques will be used to identify the genes. This work will directly lead to improved diagnosis, therapy, prognosis, and genetic counselling.