The Relation of Focal to Diffuse Epileptiform EEG Discharges in Genetic Epilepsy

Abstract

A CROSS-SECTIONAL, controlled study of 40 families, one member each of which presented with focal "temporal lobe" epilepsy, has been described.¹The type of EEG abnormality present in the probands was also seen in a close relative in 30% of these families. Similar electroencephalographic abnormalities were seen in 36% of siblings and children of probands (compared to 2% in the control group) and in 19% of parents of probands (compared to 2% in the control group). Analysis of the genetic characteristics of this electroclinical trait suggests that the disorder is transmitted by one or more autosomal dominant genes (ie, either it is caused by a single dominant gene with variable penetrance, or it is a polygenic trait).²Gene penetrance of this trait (as measured by the electroencephalogram) is low in early childhood (14% between birth and five years of age), reaches a peak in middle childhood (56% between