Hypoplasia of the cerebellar vermis in neurogenetic syndromes.

There are conflicting reports on the relationship between cerebellar vermal lobule hypoplasia and autism. Using quantitative magnetic resonance image analysis, we measured the cerebellar vermis in 125 normal individuals with a broad age range and 102 patients with a variety of neurogenetic abnormalities. We conclude that hypoplasia of cerebellar vermal lobules VI and VII is a nonspecific finding that even occurs in several conditions with-out autistic behavior. This suggests that it is not a specific neuroanantomical marker for autism, nor is cerebellar dysgenesis likely to be solely responsible for clinical autistic behaviors.