Cerebellar vermis hypoplasia in a case of cri-du-chat syndrome.

We describe a 6-year-old child who presented the phenotype of cri-du-chat disease. The study of her caryotype confirmed an interstitial deletion of the short arm of chromosome 5. The neurological examination showed mental retardation, behavioral disturbances and features of cerebellar and cortico-spinal impairment. The MRI scan of the brain showed hypoplasia of the vermis associated with dysgenesia of the corpus callosum. This is the first report of vermian hypoplasia in cri-du-chat disease. We suggest that the most likely pathogenesis of this malformation is a midline dysraphia.