Autistic traits in the Rett syndrome.

Reactions to acoustic, visual, tactile and gustatory stimuli and to social contact were recorded in a group of girls with the Rett syndrome and in two groups of girls fulfilling the criteria for the infantile autistic syndrome. The autistic syndrome was not found in several subjects in all the Rett syndrome age groups and, when it was found, it was not of the same form as in the other subject groups. It was concluded that the behavioral syndrome of autism is of little value for differential diagnosis between the Rett syndrome and primary infantile autism.