A case of Joubert's syndrome with extensive cerebral malformations.

Joubert's syndrome is a relatively rare, autosomal-recessive syndrome defined by vermis hypoplasia, hypotonia, developmental delay and at least one of two additional manifestations: abnormal breathing pattern or abnormal eye movements. Detailed descriptions of the neuropathological findings in this syndrome are scarce. We present a radiological and pathological correlation of a case of Joubert's syndrome in which, apart from the classic vermis aplasia and some malformations of the brain stem and the spinal cord, extensive malformations of the cerebrum were found. The dentate nuclei were broken into islands and showed a few heterotopias within the superior cerebellar pedunculi, the inferior olives were plump and dysplastic, and an almost complete absence of the pyramidal decussation was found. In the spinal cord, the dorsal columns were located in a dorsal position within the spinal grey matter. In the cerebrum, absence of the corpus callosum was found. Many nodular heterotopias of the cerebral cortex and of the basal ganglia, the amygdala and the diencephalon were observed. The present case is compared to previous pathological descriptions of the Joubert syndrome and to other syndromes with comparable malformations of the posterior fossa.