CHILDREN WITH FOCAL SHARP WAVES - CLINICAL AND GENETIC-ASPECTS

Purpose: To investigate the spectrum of clinical manifestations in chi ldren with benign focal sharp waves in the EEG to gain further insight into the genetic background of clinical and EEG symptomatology in a f amily study. Methods: All 147 children (134 with seizures, 13 without) met the following inclusion criteria: (a) at least one EEG with focal sharp waves characteristic of benign partial epilepsies, and (b) at l east 1 sibling investigated by EEG. The families were questioned orall y or in writing regarding the occurrence of seizures. Patients' record s were evaluated by a standardized scheme. Results: The following type s of seizures occurred: febrile convulsions (FC), afebrile generalized tonic-clonic seizures (GTCS), simple and (rarely) complex partial sei zures; and rolandic seizures in the strict sense. Neonatal seizures we re overrepresented (6%); there were no indications of lesional causes. FC occurred in 38 children (26%). As compared with unselected cases o f FC, complex symptoms were overrepresented. Family data suggested a m aternal preponderance in the transmission of FC liability, Affected re latives of FC probands manifested FC more often than did relatives of probands without FC. Families of 32 patients with typical rolandic sei zures (24% of the 134 probands with seizures) showed no aggregation of rolandic epilepsy, but did show variable seizure types. In the entire sample, EEG investigations showed focal sharp waves in 11% of sibling s aged 2-10 years. No relation existed between clinical symptomatology and sharp wave findings in siblings. In 66% of probands, the EEG disc losed generalized genetic patterns. Siblings with generalized spike-wa ves (sw) and/or theta rhythm had focal sharp waves mon often than thos e without sw and/or theta rhythm. Conclusions: The phenotypic expressi on of the genetic anomaly underlying focal sharp waves shows considera ble variability. The clinical and EEG findings are in agreement with a multifactorial pathogenesis of epilepsies with ''benign'' focal epile ptiform sharp waves.