International Rett Syndrome Foundation

Rett syndrome is a rare genetic neurological disorder that leads to severe impairments, affecting nearly every aspect of life. Rett particularly affects speech, purposeful hand use, and coordination, leaving individuals understanding more than they can communicate. Caused by a gene mutation, Rett is first recognized in infancy and occurs primarily in girls and more rarely in boys. Rett syndrome occurs almost exclusively in girls and leads to severe impairments, affecting nearly every aspect of the child’s life: their ability to speak, walk, eat, and even breathe easily. The hallmark of Rett syndrome is near constant repetitive hand movements. Rett syndrome is usually recognized in children between 6 to 18 months as they begin to miss developmental milestones or lose abilities they had gained. Rett syndrome is caused by mutations on the X chromosome on a gene called MECP2. There are more than 900 different mutations found on the MECP2 gene. Most of these mutations are found in eight different “hot spots.” Rett syndrome is not a degenerative disorder with individuals living to middle age or beyond. Rett syndrome occurs worldwide in 1 of every 10,000 female births, and is even rarer in boys. Rett syndrome can present with a wide range of disability ranging from mild to severe. The course and severity of Rett syndrome is determined by the location, type and severity of the mutation and X-inactivation.