Rett syndrome: clinical peculiarities, diagnostic approach, and possible cause.

The presentation and diagnosis of Rett syndrome at various ages and stages are reviewed. In addition to the "classic" form of this disorder, variability of phenotype exemplified by atypical patients is also examined. Characteristic peculiar manifestations of the condition are compiled from the author's personal experiences over a 28 year period. Speculations and ideas are presented on possible alternative causative mechanisms in an attempt to explain the origin of this disorder.