Rett syndrome: review and discussion of current diagnostic criteria.

Rett syndrome is a mental retardation syndrome that occurs only in females and consists of normal pre-, peri-, and neonatal growth and development. It is followed by rapid neurobehavioral deterioration in late infancy or early childhood, a developmental arrest, plateauing, and then either a course of retarded development or continued deterioration. The period of rapid neuro-behavioral deterioration manifests as a partial autistic syndrome, with loss of production and comprehension of language, hyperactivity, hyperventilation, hand-wringing, and ataxic gait. Current diagnostic criteria are discussed and suggestions for further research are presented.