Rett syndrome: a longitudinal developmental case report.

Rett syndrome is a recently described progressive neurological disorder of unknown etiology occurring only in females, causing severe to profound mental retardation and characterized by loss of purposeful hand use and stereotypic hand movements. The present study examined development in five areas: gross motor skills, fine motor skills, self-help skills, communication, and cognition. Results indicated a general stagnation in all developmental areas beginning at approximately 15 months. No skills progressed beyond the 2-year level; this, despite several years of intensive, interdisciplinary intervention. Cognitive and communication skills regressed, then stabilized for several years, and subsequently began further regression. Gross motor and self-help skills appear to be areas of relative strength.