Aicardi syndrome

This is a very rare genetic syndrome which occurs in about 1 in 100,000 to 1 in 150,000 newborn babies.

It nearly always happens in girls; it only very rarely affects boys. This is because it is thought the syndrome causes a male unborn baby to be lost in pregnancy as a miscarriage. Girls who are affected by Aicardi syndrome have developmental delay and seizures. They also have structural brain abnormalities, including a partially or completely absent corpus callosum (the structure that links the two halves, or ‘hemispheres’ of the brain together).

Girls with Aicardi syndrome have very typical eye abnormalities, which often help to make the diagnosis. The abnormalities, seen in the retina at the back of the eye, are called ‘choroidal lacunae’. They appear as very clear, round footprints or circle-shaped yellow-white lesions (marks). There may also be gaps or holes called ‘coloboma’ in the optic nerve. All of these abnormalities are visible with a special piece of equipment called an ophthalmoscope.

As well as an absent corpus callosum, some babies may have brain cysts or other brain abnormalities. These can be seen with a magnetic resonance imaging (MRI) brain scan. Other features of Aicardi syndrome include cleft lip and palate, asymmetry of the face (lopsided, uneven), microcephaly (a small head), microphthalmia (one or two small eyes) and abnormally formed bones in the spine and scoliosis (curvature of the back).

Although Aicardi syndrome is a probable genetic disorder, it does not appear to run in families and therefore is not ‘passed on’. It is thought to be caused by a spontaneous mutation (random change) in a gene that lies on one of the female (X) chromosomes. It is thought this mutation occurs at conception. The precise mutation is not known.


Seizures often happen before 3 months of age. The usual seizure type is infantile spasms. The combination of infantile spasms and an EEG pattern called ‘hypsarrhythmia’ is known as West syndrome. Less commonly, babies have other seizure types, including focal (partial) motor seizures, and focal seizures that affect their awareness. Rarely the EEG test may show abnormal discharges, or spikes and waves alternating with periods of flatness, coming independently from each side of the brain. This pattern is called ‘suppression-burst’ or ‘burst-suppression’.

The seizures may occur very frequently, including many times a day. The seizures may not respond to epilepsy medicines.


The diagnosis may not be made until seizures develop, and investigations such as an MRI (magnetic resonance imaging) brain scan and a special eye examination are carried out.


The choice of epilepsy medicine is difficult, because the seizures are often resistant to treatment. Depending on the type of seizures, medicines that may be effective include vigabatrin (Sabril), sodium valproate (Epilim) and a short course of corticosteroids (called prednisolone). However, other medicines may also be useful, including clobazam (Frisium), levetiracetam (Keppra) and topiramate (Topamax).

The ketogenic diet is a treatment that might be very helpful. This is a special diet and its use will need to be supervised very carefully particularly in children aged less than 3 years.

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

There may be research studies open that your child might be able to take part in. Your child’s paediatric neurologist will be able to discuss this with you.

Your child is very likely to have prolonged or repeated seizures as part of Aicardi syndrome. This may include status epilepticus. 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 severity of Aicardi syndrome varies. Generally, the younger the age at diagnosis, the more severe the epilepsy and learning difficulties will be. Most girls with Aicardi syndrome will have moderate or severe learning disabilities. There are reports of children who are less severely disabled, but most will remain dependent on others for all of their life. This is particularly true for the very few boys who have this syndrome. All children with Aicardi syndrome may have problems with feeding, and may develop stiffness (spasticity) in their arms and legs. They may also have difficulties with their vision and be registered as being ‘partially-sighted’ or ‘blind’. Rarely some girls may learn to walk and develop some limited speech. They frequently have complications such as chest infections, which may shorten their life.


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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 electroencephalogram (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.

  • Updated December 2019
    To be reviewed December 2022

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