Familial neuronal migration disorder: subcortical laminar heterotopia in a mother and pachygyria in the son.

We describe clinical manifestations and magnetic resonance imaging (MRI) findings in a man and his mother who were diagnosed as having a neuronal migration disorder. The son had severe psychomotor retardation and the mother had intractable seizures and mild psychomotor retardation. MRI demonstrated moderate pachygyria in the son and subcortical heterotopia in the mother. In both patients, the frontal parts of the brain were characteristically more affected than any other areas. A dominant pattern of inheritance in the family suggests a genetic role in the underlying cause of the migration disorder. The difference in severity between the two patients also suggests an X-linked dominant inheritance. Our family fits the condition of X-linked lissencephaly.