Rett syndrome: a significant proportion of girls affected by autistic behavior.

The main clinical features of 20 girls affected by the Rett syndrome are described and for 3 of them more detailed case reports are given. Fifteen of these girls were observed for the first time between October 1983 and February 1985. In the same period 25 other girls with the complete features of infantile autism were also seen for the first time. The marked loneliness with gaze and hearing avoidance and the speech abnormality of girls with the Rett syndrome are also discussed.