Clinical features of the early stage of the Rett syndrome.

Our previous reports have pointed out that the Rett syndrome (RS) starts from early infancy with autistic behavior and muscle hypotonia, and we have raised the hypothesis in regard to the pathophysiology that RS can be an early developmental disorder of the monoaminergic and indolamine systems. This paper presents the reanalysis of early motor and behavioral features performed on 16 patients. The most frequent complaint was developmental delay, but 2 cases were presented with autistic behaviors. Development showed delay even from head control. Crawling was particularly difficult. Muscle hypotonia was present in all cases. Early autistic behaviors were seen in high degree and the most frequent was the pervasive lack of social association. Autistic behaviors characterizing older autism were seen in various degrees. These findings reconfirm our previous reports and hypothesis. Furthermore, it can be suggested that the onset may even be in the fetal stage and that lesions of specific neuronal systems occurring in early ontogeny could result in specific abnormality in the higher system which manifest later in development, after these structures reach certain levels of maturation.