[Electroencephalographic studies of family members of patients with juvenile myoclonic epilepsy].

Juvenile myoclonic epilepsy (JME) is a common idiopathic generalized epilepsy (IGE); it has a clinical and probably a strong genetic relation to the other IGE forms. Generalized spike/polyspike-wave discharges (SW/PSW) are typical of all IGEs. The aim of our study was to determine the incidence of epilepsy and SW/PSW in EEG of family members of 12 JME patients. 35 first degree relatives aged over 15 years were examined. 40 min EEG with 5 min HV were recorded. IGE was diagnosed in 3 (8.6%) persons: JME in 2 and childhood absence epilepsy (CAE) in 1 person. Six more relatives (17.1%) had typical SW/PSW traits in EEG. Thus the IGE features were found in 9 (25.7%) individuals--members of 7 out of 12 families (58%). EEG of 7 other relatives (20%) revealed non-specific episodic diffuse or focal abnormalities. The above results reveal higher incidence of different kinds of ICEs and typical EEG traits in families of JME patients. This findings confirm familial susceptibility to IGE and may be helpful in genetical counselling.