Rett syndrome is a genetic developmental disorder. Although it almost always affects girls, it may be seen, rarely, in boys. In most cases, the syndrome is caused by mutations on the X chromosome on a gene called MECP2. However, there are children who have signs and symptoms of Rett Syndrome who do not have this genetic mutation and others who have a different genetic mutation.
Rett syndrome was identified by Dr. Andreas Rett, an Austrian doctor who first described it in an article in 1966. However, it was not until after a second article about the disorder was published in 1983 that the disorder was generally recognized.
The MECP2 gene makes a protein that is necessary for the normal development of the nervous system- especially the brain. Rett syndrome affects areas of brain function that are responsible for cognitive, movement, sensory, emotional, motor and autonomic function. These, in turn, can have an impact on learning, speech, sensory sensations, mood, breathing, cardiac function, as well as chewing, swallowing and digestion.
Most babies who has Rett syndrome appears to have typical development for the first months of life. At 6 to 18 months, development slows and many children will have a loss of previously learned skills. The first symptom is often low muscle tone (hypotonia) and diminished eye contact. Over time, girls with Rett syndrome develop problems with communication skills and intentional use of their hands and they start to make repetitive hand movements often similar to washing motions. The normal rate of head growth begins to slow. Some girls with Rett syndrome develop seizures and/or irregular breathing patterns during the waking hours. Over the long term, there is a decline in motor function including the ability to ambulate in some girls. The rare boys with Rett syndrome have a variety of clinical presentations.
Children with Rett syndrome can display a broad array of disabilities, ranging from mild to severe. The progression and severity of the disorder depends on a variety of genetic mechanisms. (See What Causes Rett Syndrome)
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Want to learn more about Rett syndrome?
National Institute of Neurological Disorders and Stroke
International Rett Syndrome Foundation