Genetic aspects of childhood epilepsy
Hermann Doose, MD
Neuropediatric Department, University of Kiel, Schwanenweg 20, D-2300 Kiel, West Germany
Wolfgang Baier, MD
SINCE ancient times, genetic factors have been known to contribute to the manifestation of epileptic seizures. Although a large number of investigators have attempted to delineate the role of genetic influence more precisely, our present understanding of the topic is still insufficient. Only a small proportion of epileptic conditions are caused by monogenic inborn errors of metabolism. The genetic background of the vast majority of the epilepsies cannot be explained by single gene theories; it requires models allowing for a polygenic disposition. Attempts to formulate more or less globally valid polygenic models have not yet been successful. All that can be said with certainty is that the pathogenesis of epilepsy is multifactorial.1
Until the present time, most studies of the genetics of epilepsy have concentrated on the obvious symptom, the epileptic seizure.2 This is still the case, although it has been known for decades that “the clinically observed phenotypes of epilepsy represent only the tip of the iceberg,”3 the basis of which is constituted by a complex and much more widespread phenomenon: the so-called convulsive liability. Instead of dealing with the “iceberg's tip,” it should be more productive for the following review to focus attention on this more fundamental phenomenon.
During recent decades, electroencephalographic (EEG) research has made important contributions to our understanding of the genetically determined convulsive liability. Already in the early days of clinical electroencephalography, it could be shown that EEG symptoms of an increased convulsibility can be detected in up to 40% of healthy relatives of epileptic. . .