While some epilepsies are caused by well described genetic factors, the underlying genetic component to temporal lobe epilepsy (TLE) is poorly understood. The experience of the research community to date has shown that endophenotypes are required to augment the power of genetic mapping studies in neurological disorders. Based on in-vivo quantitative magnetic resonance imaging, this programme will identify subtle structural variations in the brain which are both heritable and involved in the development of temporal lobe epilepsy (TLE). These novel endophenotypes will then be measured in a larger cohort of epilepsy patients for whom whole genome association data is already available. This combined large-scale genetics and neuroimaging dataset will be used to assist in mapping the genetic component to epilepsy.