Purpose: To describe a family in whom two sisters with epilepsy, mental retardation, and microcephaly had different malformations of cortical development detected by magnetic resonance imaging (MRI).
Methods: Clinical investigation of the patients and their family. High-resolution MRI, cognitive testing, and repeated EEG recording in both patients.
Results: In one patient, the malformation was bilateral and diffuse but much more pronounced in the parietal and occipital regions, with MRI characteristics indicating pachygyria-polymicrogyria. In the other patient, the abnormality 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 microcephaly, 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 this family indicate that unilateral malformations of cortical development detected during investigations after seizure onset may be genetically based, suggesting that a single genetic abnormality could be responsible for bilateral or unilateral malformations.