Of the 158 persons studied, 30 had the double-cortex syndrome (also called subcortical band heterotopia), 20 had polymicrogyria with megalencephaly, 61 had periventricular nodular heterotopia ...

usually in the deep cerebral white matter or lining the walls of the lateral ventricles (periventricular nodular heterotopia). This condition is on the spectrum of neuronal migration disorders.

By studying four generations of this family, the speaker, Peter Huttenlocher, had found that girls inherited the disorder, called periventricular nodular heterotopia (PVNH), from their mothers.