Familial mesial temporal lobe epilepsy is a common focal epilepsy syndrome that typically begins in adolescence or adulthood. Affected individuals have focal aware seizures with mesial temporal lobe features, especially prominent déjà vu. Most patients have a normal MRI, and seizures respond to treatment. A subgroup is recognised that have antecedent febrile seizures, hippocampal atrophy, and drug resistant seizures. Direct questioning of relatives may be required to identify this familial epilepsy syndrome, as many individuals consider their déjà vu experiences as mild and they may not have been diagnosed as seizures.
Age at seizure onset ranges from 3 and 63 years, but usually is in adolescence or adulthood.A female predominance has been reported. Antecedent birth, development and cognition are typically normal. Antecedent febrile seizures may be found in a subgroup of individuals. Neurological examination is normal. Seizures may be mild phenomena and do not always require treatment..