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Rett syndrome

This syndrome happens in about one in every 10,000-12,000 girls. It very rarely affects boys, but when it does, they are always affected far more severely than girls. Rett syndrome is caused by a genetic abnormality, called a ‘mutation’. This abnormality or mutation is usually found on one of the sex chromosomes – the X chromosome. The most common mutation is called the MECP2 mutation. A different and much less commonly found genetic mutation is nearly always seen in those children with Rett syndrome who have a very severe type of epilepsy. This less common mutation is called the CDKL5 mutation.


Girls with Rett syndrome may show normal development for the first 6 or, rarely, 12 months of their life. Then, usually between 6 and 30 months of age (often between 6 and 18 months of age), their development slows down. They may even lose skills that they had previously learned; this is called ‘developmental regression’. They become less interested in play, lose the ability to speak and may become irritable and scream for no obvious reason. They stop using their hands purposefully and they may, instead, begin to move their hands in a repetitive way. This often takes the form of hand-wringing or hand-washing movements.

Most children will never learn to speak. Those that do usually only have a few words and cannot speak in complete sentences.

Epilepsy eventually happens in about 9 out of 10 children. It usually begins after the age of 2 years, but may begin in the first year of life. The seizures may be of various types, including generalised convulsive (tonic-clonic), absences (where the child goes blank), myoclonic (jerks), and tonic seizures (where the child stiffens). A child may also have focal seizures (where consciousness may or may not be affected). A particular type of seizure called infantile spasms may also happen. This type of seizure particularly happens in the first year of life in girls and boys with the less common genetic mutation (the CDKL5 mutation).

Often more than one seizure type is present. Frequently, girls with Rett syndrome have periods of rapid or slow breathing. Often the breathing may stop altogether and this is called an ‘apnoea’. This may last for a number of seconds. The periods of slow breathing are sometimes associated with faints, which can be mistaken for epileptic seizures. Some girls will also have a disturbance of their heart rate and rhythm. The medical name for this is an ‘arrhythmia’.

When boys are affected, the epileptic seizures nearly always start within the first few weeks or months of life, and are usually extremely difficult to treat.


The discovery of the genetic mutation in Rett syndrome has made it much easier to diagnose the condition. However, it is obviously important for doctors to think about the condition in the first place, so that the blood test can then be done to look for the genetic mutation. This common mutation is found in about 8 out of every 10 girls with Rett syndrome. Before the genetic mutation was discovered, the diagnosis of Rett syndrome was not usually made until girls were much older - usually at 4 or as late as 6 years of age, sometimes older.

The EEG (electroencephalogram), which measures electrical activity in the brain, may show features which suggest Rett syndrome, even when epilepsy is not present. It can, therefore, be useful in diagnosis. Brain scans (MRIs) are normal in children with Rett syndrome.


Treatment of Rett syndrome can be very difficult. Epilepsy medicines that are often used, include sodium valproate (Epilim), lamotrigine (Lamictal), carbamazepine (Tegretol, Tegretol Prolonged Release) and clobazam (Frisium). Other medicines, including piracetam (Nootropil) and sulthiame (Ospolot), may help to control seizures in some cases.
The ketogenic diet might also be helpful, particularly if the child has feeding problems and has to be fed through a feeding gastrostomy tube (called a ‘PEG’ tube).

Information about treatments for children can be found on the Medicines for Children website.

There may be research studies going on in this epilepsy syndrome. Your child’s hospital doctor will be able to discuss this with you.

Your child is very likely to have prolonged or repeated seizures as part of Rett syndrome. Your child’s hospital doctor (paediatrician or paediatric neurologist) will discuss a ‘rescue’ or emergency care plan with you to treat any prolonged or repeated seizures that may happen at home. This rescue or emergency care plan is important for your child.


The seizures usually become less of a problem in adolescence and early adult life, but only occasionally will the seizures stop completely. There is usually increasing difficulty with walking, and many children or adolescents eventually are not able to walk. Older children and teenagers will need special attention to prevent scoliosis (a bending or curvature of the spine).

Feeding may also be a problem, particularly in early childhood. Some children will need to be fed through a nasogastric tube (tube inserted through the nose) or a feeding gastrostomy tube (this is a tube inserted directly into the stomach – and is known as a ‘PEG’ tube).

The lifespan of people with Rett syndrome is shortened, but most people will live into early or middle adulthood. Unfortunately, most boys with Rett Syndrome will have a very shortened lifespan. Finally, all girls with Rett syndrome need complete care throughout their lives.


Rett UK
Helpline: 01582 798 911
Email: support@rettuk.org
Website: rettuk.org

Freephone helpline (UK only): 0808 808 3555
Website: cafamily.org.uk
Email: info@cafamily.org.uk 

Together for Short Lives
Freephone helpline: 0808 8088 100
Website: togetherforshortlives.org.uk

What is a syndrome?

A syndrome is a group of signs and symptoms that, added together, suggest a particular medical condition. In epilepsy, examples of these signs and symptoms would be things like the age at which seizures begin, the type of seizures, whether the child is male or female and whether they have physical or learning disabilities, or both. The results of an EEG are also used to help identify epilepsy syndromes.

If you would like to know more about an epilepsy syndrome, please speak to your doctor. If you would like to know more about epilepsy in general, please contact Epilepsy Action.


Epilepsy Action would like to thank Dr Richard Appleton, consultant paediatric neurologist at Alder Hey Children’s Hospital, Liverpool, UK for preparing this information.

This information is exempt under the terms of The Information Standard.

  • Updated November 2016
    To be reviewed November 2019

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