We present cranial magnetic resonance imaging (MRI) findings in a 6-year-old boy with Opitz syndrome. The electroencephalogram revealed epileptiform abnormalities in both frontal regions. MRI showed normal callosal development, but a rounded shape of the left hippocampus due to malrotation. The temporal horn was slightly dilated on the left side. These features were consistent with isolated hippocampal malrotation. (C) 2003 Elsevier Science Inc. All fights reserved.