Familial epilepsy with unilateral and bilateral malformations of cortical development

Purpose: To describe a family in whom two sisters with epilepsy, mental ret ardation, and microcephaly had different malformations of cortical developm ent detected by magnetic resonance imaging (MRI). Methods: Clinical investigation of the patients and their family. High-reso lution MRI, cognitive testing, and repeated EEG recording in both patients. Results: In one patient, the malformation was bilateral and diffuse but muc h more pronounced in the parietal and occipital regions, with MRI character istics indicating pachygyria-polymicrogyria. In the other patient, the abno rmality involved the right hemisphere, predominating around the perisylvian region, with MRI more clearly indicative of polymicrogyria. A brother also had severe epilepsy, diffuse EEG abnormalities, mental retardation, and mi crocephaly, but could not be studied neuroradiologically. Conclusions: Lack of MRI studies in the parents and brother does not allow a precise hypothesis on the mode of transmission. However, findings from th is family indicate that unilateral malformations of cortical development de tected during investigations after seizure onset may be genetically based, suggesting that a single genetic abnormality could be responsible for bilat eral or unilateral malformations.