Focal grey matter heterotopias in monozygotic twins with developmental language disorder

We describe 9-year-old monozygotic male twins with a developmental language disorder of the phonologic-syntactic type and learning difficulties. High-resolution MRI revealed bilateral parieto-temporal grey matter heterotopias in both twins, on the left more than on the right, and more pronounced in the more affected twin. This suggests a causal relationship between the heterotopias and the neuropsychological findings in this twin pair.Neuronal migration defects and ensuing focal heterotopias may be causally related to developmental language disorders.