Outcome of bilateral periventricular nodular heterotopia in monozygotic twins with megalencephaly

Abstract

Bilateral periventricular nodular heterotopia (BPNH) is a neuronal migration disorder, characterized by grey‐matter cellular rests in the periventricular regions. Patients frequently present with seizures during childhood or later in life. Monozygotic twin sisters were found to have enlarged head circumferences (>95th centile) during a routine medical visit at 6 months of age. A brain CT scan revealed grey‐matter cellular rests in the subependymal regions extending to the subcortical white matter. In some areas these cell aggregates had nodular margins, consistent with the diagnosis of BPNH. At 6 years of age they are cognitively and neurologically normal. They have not had any seizures and their heads continue to grow along the 95th centile.