Frequency of epilepsies in family members of patients with different epileptic syndromes.

Aim: To determine the frequency of epilepsies in the family members of epileptic patients. Methods: The records of 4,851 patients with epilepsy were reviewed. The frequency and patterns of different epilepsies and epileptic syndromes in the patients, number of affected relatives and consanguinity were studied. Results: A total of 1,753 patients were excluded due to various reasons. Of the remaining patients, 296 (9.5% of 3,098) had first-or second-degree relatives affected with seizures. The incidence of family history in the localization-related cryptogenic epilepsies group was significantly higher than all other groups (246 patients). Juvenile myoclonic epilepsy was the most frequent epileptic syndrome (34 patients). Consanguinity was detected in 56 patients, and 33 (58.9%) of these subjects were in the localization-related cryptogenic epilepsies group. Of all subjects, 59 (19.9%) had more than 1 epileptic family member. The ratio of affected first-to second-degree relatives was 202/94. Conclusions: A considerable number of the relatives of epileptic patients have seizures. The risk of relatives being affected depends on their relationship with the proband. Genetic factors may play an almost equal role in the predisposition of relatives to epilepsy in families of probands with cryptogenic and idiopathic epileptic syndromes. Copyright (C) 2010 S. Karger AG, Basel