[Rett syndrome. A report of fifteen cases].

In its typical form, Rett syndrome is characterized by the development, towards the end of the first year of life, of neurologic abnormalities in a formerly healthy girl. Our analysis of 13 observations of "classical" Rett syndrome shows that the most common findings include cognitive regression, autistic behavior, hypotonia, apraxia, and very suggestive stereotyped movements. Two other cases emphasize the problems raised by mild, atypical or incomplete forms. At present, there is no biological or morphological marker for this syndrome whose pathophysiology is unknown. Increased levels of beta-endorphins in the cerebrospinal fluid may prove to be a marker and suggests therapeutic possibilities.