Genetic factors in childhood epilepsy with focal sharp waves. II. EEG findings in patients and siblings.

Electroencephalographical investigations were performed in 203 epileptic children exhibiting focal sharp waves in the EEG and in 312 siblings. As controls served 685 brain-healthy children (Gerken 1971) as well as 252 children with spike wave absences and their 242 siblings (Doose et al. 1973). According to the EEG findings in probands so-called "centrencephalic" EEG-criteria (theta rhythms, spikes and waves, photosensitivity) as a symptom of a genetically determined seizure susceptibility can be expected in at least 60% of the probands. 18% of the siblings showed at least once one definite "centrencephalic" EEG pattern. These results must be regarded as minimal values, since in siblings only one electro-encephalographic study could be performed. The results make it evident, that in the pathogenesis of epilepsy with focal sharp waves a genetically determined seizure susceptibility plays a very important role. After comparison with the results of genetic investigations in patients with spike wave absences (Doose et al. 1973) the difference as for the genetic basis between "centrencephalic" and focal epilepsies apparently is only due to a different gene density.