So it is possible that a defect in Purkinje cell development could impede the function of the cerebellum in ways we do not now understand. We now believe that autism represents a severe developmental disturbance of the brain that most likely occurs at the late or end stages of brain development, during which the final connections between brain cells are established that will define the communication network of the mature brain. We believe that these developmental disturbances giving rise to infantile autism are the result of genetic mutations, occur during the end stages of brain differentiation, and take place in circuits affecting the limbic structures, the temporal cortex and possibly the cerebellum that are responsible for language and information processing, and the emotional coloration that accompanies it. Like any hypothesis, this one must be verified experimentally. These recent advances in an anatomic understanding of autism have also tied it more closely to another severe developmental disorder, schizophrenia.
Schizophrenia is also a disorder of brain development which affects children and adolescents.
Schizophrenia is more common than autism, affecting around 1 percent of the population. Like autism, schizophrenia is a highly heritable disorder. For many years, researchers believed autism and schizophrenia were different variants of the same disorder, but epidemiological research showed that the two disorders did not occur more frequently in the same families than would be predicted by chance, so since about 1971, we have taught that they are distinct. However, more recent research suggests they may be related. Irvine all implicates maldevelopment of centers in the medial temporal cortex and limbic structures in the pathogenesis of schizophrenia.