The borderland of autism and Rett syndrome: five case histories to highlight diagnostic difficulties.

Four girls and one boy with pervasive developmental disorders are described. They all met DSM-III-R criteria for autistic disorder and all also showed many if not all the symptoms currently considered essential for a diagnosis of Rett syndrome. It is concluded that there is considerable overlap between the two disorders and that the symptomatic similarities might mirror common pathophysiological abnormalities at the brainstem level.