Rett Syndrome

14th May 2020

Rett Syndrome is a genetic syndrome that is estimated to affect just 1 in every 10,000 to 12,000 girls. It is extremely uncommon for males to be affected by Rett Syndrome, however, on the rare occasion that it does it’s always far more severe than it is in females. 

Rett Syndrome is caused by a genetic abnormality, or ‘mutation’. Rett Syndrome can refer to a number of mutations, which are usually found on the X chromosome, which is a sex chromosome and explains why females are affected more commonly than males. The most common of these mutations is known as the MECP2 mutation. The less common and more severe mutation is called the CDKL5, it’s this version that has the potential to affect both males and females. 


Children with Rett syndrome will often start life showing normal development for at least 6 months, and in some rarer cases for up to 12 months. However, between 6 and 30 months their development will start to noticeably slow. In some cases, children with Rett syndrome will even begin to regress and lose skills that they had previously learned.     

Heart rate and rhythm can also be disturbed, medically this is known as an arrythmia, which can be one of the telltale signs of Rett syndrome and as well as being a symptom will also likely be part of the diagnosis process. An abnormal breathing pattern is also a common symptom of Rett syndrome and may include periods of hyperventilation, which means rapid breathing that lasts between 10 and 60 seconds and sometimes longer. This can be followed by periods of low, shallow breathing known as hypoventilation. 

Seizures will occur at around age 2 in the vast majority of children with Rett syndrome (approximately 9 out of 10). Seizures can present in various types, including tonic-clonic, absence, myoclonic and tonic. Focal seizures where the child appears to lose some awareness may also happen. 

For more information on seizures and the different types, please click here. 


Since the mutations that cause Rett Syndrome have been discovered it has become much easier to test for the syndrome once a doctor suspects it may be present. Blood tests can be used to test for the MECP2 and CDKL5 mutations, the former of which is found in 8 out of 10 girls with Rett Syndrome. Before this discovery was made, a diagnosis would not be made until the child was much older, at around ages 6 or 7. 

An EEG (electroencephalogram) test can be used to monitor electrical brain activity for patterns which may suggest Rett syndrome. These can show even before epilepsy is present. Brain scans, such as a magnetic resonance imaging (MRI) scan can also be useful in making a diagnosis of Rett syndrome. 


Unfortunately, treatment for Rett syndrome can become extremely complex. Finding the optimum anti-epileptic medication (AED) or combination of AEDs can be difficult. The medications that are often used with this syndrome include sodium valproate, lamotrigine, levetiracetam, carbamazepine and clobazam.

In some cases, the ketogenic diet can help to control seizures and may be particularly helpful if the child is fed using a PEG tube. 


Seizures will often begin to reduce in terms of frequency and severity during adolescence, however, it’s very rare that they will stop altogether. Difficulty walking is common and for many children with Rett syndrome their ability to walk will deteriorate over time. 

Feeding can be problematic for children with Rett syndrome, particularly during childhood. This can result in the child needing to be fed via a PEG tube. 

Those with Rett syndrome will have a shortened lifespan, but most will live into early/middle adulthood. Unfortunately though, boys who develop Rett syndrome will most likely have a more dramatically reduced lifespan. 

Most people with Rett syndrome will require lifelong care and be unable to live independently.

National Epilepsy Training can help…

For more information on Rett Syndrome, please call us on 01706 373075 or email