What is Rett Syndrome?

Rett syndrome is a rare but serious neurological disorder that affects about 1 in 9,000 girls. Even more rarely, boys may be affected.


In 1999, it was discovered that Rett syndrome is commonly associated with a mutation in the MECP2 gene. The clinical diagnosis has often been uncertain in early childhood as the symptoms may be confused with those occurring in other disorders such as autism, cerebral palsy and non-specific global developmental delay. However, since the discovery of the association with abnormalities in the MECP2 gene the clinical diagnosis is now often confirmed by genetic testing.


  • In most cases, early development is normal.
  • However, some time in the first 6 to 18 months of life, the normal pattern of childhood development does not progress.
  • In most cases there is a loss of communication and hand skills and the development of unusual hand movements, such as wringing, clapping and mouthing.
  • During this time the child may display autistic features and appear agitated and distressed.
  • In the long term, most children are no longer able to talk and many find it difficult or are unable to walk.
  • Other clinical features include poor growth, seizures, spinal curvature, altered breathing patterns, low bone density, gastrointestinal and sleeping problems.
  • Therefore, Rett syndrome is usually associated with severe disability and sometimes with considerable health problems. However, despite this many parents find that over time, their daughter may appear to improve in her social awareness and communication skills, and may learn more gross motor skills.