Definition of Rett Syndrome

Definition of Rett Syndrome: Characteristics

Children with Rett syndrome typically develop normally during at least the first five months and then experience deterioration in motor skills, social interactions and coordination. The disorder was first identified in 1965 when Austrian physician Andreas Rett described the progressive loss of skills.

Rett syndrome almost exclusively affects girls because it appears to be caused by a genetic mutation on the X chromosome. Boys who inherit the gene usually die before birth. The definition of Rett syndrome includes typical early development followed by deceleration in head circumference, loss of purposeful hand skills and development of stereotypic hand movements, regression in communication, cognitive and gross motor skills. Typical gait abnormalities include toe-walking, unsteadiness and wide-based, stiff-legged walk. In addition, muscle rigidity, spasticity and contractures and/or scoliosis may develop over time. Symptoms of a seizure disorder, sleep problems, teeth grinding, feeding/eating difficulties, hyperventilation (while awake) and poor circulation also support the Rett syndrome diagnosis, although they may not necessarily occur.

Making a Diagnosis

A neurologist, clinical geneticist or developmental pediatrician may make a diagnosis by observing early symptoms and noting skill regression as symptoms begin to manifest. A genetic test may be given to see if there is the characteristic mutation on the X chromosome.

During diagnosis the healthcare professional will also try to determine whether symptoms may be due to other disorders. For example, children who are male, who have abnormally small heads at birth, an identifiable metabolic disorder or brain damage due to infection or head trauma shortly after birth can be excluded from having a Rett syndrome diagnosis.

Definition of Rett Syndrome: Four Stages of Regression

Rett syndrome regression is described as following four stages.

During stage one– development and growth appear to stagnate and the child begins to show decreased interest and interaction with the environment.

During stage two – (typically between two and five years of age) loss of purposeful hand movements is replaced by stereotypic hand wringing and the child may be misdiagnosed with autism because he or she is not developing typical language and cognitive skills.

During stage three – physical disorders such as apraxia and ataxia become more severe (typically after five years of age).

During stage four – further physical and cognitive deterioration such as muscle wasting and decreased mobility.

Impact of Rett Syndrome on Communication

Children with Retts syndrome have cognitive impairments that interfere with understanding and speaking words. Muscle atrophy, breathing abnormalities and decreased coordination of the oral motor (mouth) muscles also impact abilities to speak as well as control chewing and swallowing food. However, some girls with Rett syndrome can learn to use picture communication boards by touching or pointing to requests. In addition, eye gaze technologies that involve tracking eye movements using cameras and reflected infrared light might enable children to identify pictures and engage in other cognitive processes. Therapeutic strategies such as these can contribute to quality of life despite the expected loss of skills.


Richard, G. and Hoge, D.; The Source for Syndromes; East Moline, Illinois: Linguisystems; 1999.

Smith, J, Allen, A and O'Brien, J. ; Occupational Therapy for Children; Boston, Massachusetts: Mosby; 2009.

Rett Syndrome Fact Sheet