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Rett syndrome is a genetic disorder that affects approximately 1 in 12,000 females (it is rarely seen in boys). It causes severe physical and mental disability that begins in early childhood.
Rett syndrome usually goes unnoticed for the first few months of the child's life, although parents often realise with hindsight that their child did show some features of the condition quite early on.
Parents tend to first become aware of the condition when their child fails to develop normally and begins to show some of the signs mentioned below.
Experts generally describe four stages of the disease, although symptoms will overlap between each stage. The main features of each stage are described below.
Stage one describes the changes that typically appear in the first 6-18 months of the infant's life. These include:
Stage two, or the 'rapid destructive stage', usually begins between the ages of one and four and may last for weeks or months.
Your child will gradually or suddenly start to develop severe problems with communication, language, learning, co-ordination and other brain functions.
Signs at this stage include:
Stage three of the disease usually begins between ages 2 and 10 and can last for years.
At this stage, girls are considered to have emerged from the period of regression in stage two.
Prominent symptoms during this stage may be:
Also, about 70% of infants will develop epilepsy, usually after the age of two. Many develop irregular breathing patterns (for example, holding their breath or shallow breathing followed by rapid, deep breathing) and some may develop heart rhythm abnormalities.
During this stage a girl with Rett syndrome may show:
Many girls remain in this stage for most of their life.
Stage four can last for years or even decades. The main symptoms at this stage are:
However, the repetitive hand movements may decrease and eye gaze usually improves.
The seizures usually become less of a problem in adolescence and early adult life, although they will normally be a lifelong problem to manage.
Almost all cases of Rett syndrome are caused by a mutation (change in the DNA) in the MECP2 gene, which is found on the X chromosome (one of the sex chromosomes).
This gene contains instructions to make a particular protein (MeCP2) that is vital for brain development. The gene abnormality prevents nerve cells in the brain from working properly.
Almost all people with Rett syndrome have no history of the disorder in their family, and the mutation has happened spontaneously.
Each person normally has one pair of sex chromosomes in each cell – females have two X chromosomes and males have one X and one Y.
Rett syndrome results when half the cells in the child's brain and spinal cord are normal and half are abnormal (the child survives, but has a severe disability). This happens when the child has one X chromosome with the severe MECP2 abnormality and one X chromosome with the normal version of the gene. The child is almost always female as males don't have a second X chromosome.
Rare exceptions of Rett syndrome in males occur when, for example, the male is born with an extra X chromosome so he has three sex chromosomes (XXY; known as Klinefelter's syndrome), or when the change is found in only some of the boy's cells (known as mosaicism).
Males who carry the abnormal MECP2 gene on their only X chromosome will usually develop a serious condition known as infantile encephalopathy and will not often survive beyond two years.
Males with less severe changes in their MECP2 gene can live a long life and are affected with learning difficulties but usually less severely than in Rett syndrome. Females who carry such (milder) changes on one of their two X chromosomes will often be perfectly healthy.
If Rett syndrome is suspected from your child's symptoms, a blood test can be carried out to look for the genetic abnormality that has caused it.
However, the change in MECP2 is not found in every child with the condition – so finding the gene can confirm the diagnosis, but failing to find it does not rule out the condition.
There is no cure for Rett syndrome and the symptoms can be very difficult to manage. You are likely to need help from a wide range of different health professionals.
Your child may benefit from some of the following treatments and aids:
Therapeutic horseriding, swimming, hydrotherapy and music therapy have been reported to be beneficial. Ask your healthcare team where you can access these therapies.
Girls with Rett syndrome will be dependent on 24-hour care throughout their lives. Their lifespan is shortened but many live into adulthood.
As a parent carer, it's important that you look after your own health and wellbeing too. The box on this page provides links to further information that may help you.
Important: Our website provides useful information but is not a substitute for medical advice. You should always seek the advice of your doctor when making decisions about your health.