Study Discovered New Genes Causing Childhood Epilepsy | Children's & Teens Health articles | Family Health center

A group of seizure disorders called epileptic encephalopathies, affect the developing brains of babies and children. They are devastating disorders as, in addition to causing severe disruptive seizures, they lead to retarded development in terms of intellectual ability and behaviour, and sometimes to death. It is thought that the seizures damage the child’s developing brain, affecting development.

New research, published this year has made discoveries that might make it easier to diagnose and design targeted treatments for these particular disorders.

What are epileptic encephalopathies?

There are over 40 different types of epilepsy and the one which featured in the new research is a particularly devastating one. It is thought that the development of the child’s brain is the trigger for the seizures seen in this type of epilepsy, which means that the characteristics of the seizures change as the child becomes older and the brain matures. In fact the seizures usually stop in adolescence.

But in a cruel twist of fate, the seizures cause irreversible damage to the maturing brain, leading to mental incapacity and behavioral problems.

What was ground-breaking about this research?

A research team at University of Melbourne and the Florey Institute of Neuroscience and Mental Health, headed up by Professor Ingrid Scheffer, worked out some of the genes responsible for causing this terrible illness. They analyzed genetic material from 500 children with the disorder, using state-of-the-art techniques. These enabled them to target genes known, or suspected of being the faulty ones, which cause the condition. Previously they would have had to look through thousands of genes in a very labor-intensive and inefficient way.

What did they discover?

Of the 65 genes they analyzed from the cases of epileptic encephalopathy, 19 were known to be associated with the disorder and the other 46 were suspected of it.

In more than 10% of the cases they found that the suspect genes had mutated, leading to development of the condition. A mutation is a spontaneous change in a gene, meaning it does not function in the way that it should, leading to development of a disorder.

To use a more widely-known example, the BRCA genes associated with breast cancer normally prevent cancer by repairing damaged DNA. It is only when they become faulty through a mutation that breast cancer can develop.

Two new genes, called CHD2 and SYNGAP1, which had not previously been known about, were found to be associated with development of this particular epileptic disorder.

What difference will this discovery make?

Knowing where the disorder originates could lead to the development of targeted therapies, aimed at the faulty genes. It will also improve diagnosis of this condition.

Because there are so many different types of epilepsy and because of the difficulty in diagnosing conditions in very young children, there may have been delays in the past in giving parents a diagnosis, which can be very unsettling for them.

Read More: Epilepsy: Seizures When Sleeping

In addition until a firm diagnosis can be made, it is difficult to give parents a prognosis ie tell them what the child’s future may hold, or to give appropriate treatment.

But as a result of these discoveries, in the future children with epileptic disorders can be tested for the presence of the faulty genes, to assist in diagnosis.

The lead researcher, professor Ingrid Scheffer commented :

‘This is a very exciting breakthrough which could lead to dramatic benefits in the lives of the children who suffer this condition.’

Genetic counseling

Parents of affected children will also be able to benefit from genetic counseling as a result of these discoveries. This means that even before birth a fetus could be tested for the presence of the faulty gene so that parents would have warning that their child could have the disorder. If appropriate, those with the disorder could also receive counseling about the risk of passing it on.

Prof. Scheffer said: ‘Overall, our findings have important implications for making a diagnosis in patients, optimizing therapy and genetic counseling for families.’

What is epilepsy?

It is a brain disorder associated with seizures (fits), although not all seizures are caused by problems in the brain.

Our brain is packed with nerve cells (neurones), which transmit electrical impulses so that messages that arrive in the brain from part of our body, for example telling you that you have a pain in the sole of your foot, are passed to the relevant parts of the brain. In this case the message would activate parts of the brain associated with feeling pain but also to the part for movement (the motor cortex) which can send a message to the leg to say ‘Move the foot off that drawing pin’!

In epilepsy if these messages are either disrupted or too many sent at once, there can be a ‘storm’ of electrical activity, resulting in a seizure.

Many people think of these as consisting of very violent uncontrolled movements leading to the person collapsing and being unconscious. The fact is that there are many different types of seizure, and they vary from the violent physical fits just described, to what used to be called ‘absence seizures’ where a person (usually a child) can merely appear as if they are daydreaming and not quite ‘with it’.

What causes epilepsy?

In the case of the type of epilepsy highlighted in this article, it is caused by faulty genes. But epilepsy can also be caused by other medical conditions (when it is called ‘symptomatic’) such as brain tumors, infections, multiple sclerosis or systemic lupus erythematosus. Other times the cause is not known (when it is termed ‘idiopathic’). It most commonly occurs in children and older people and unlike the type featured in this article, does not lead to brain damage, even in children.

Can it be treated?

Yes, there are drugs which can reduce the number of seizures and sometimes suppress them all together. Alternatively, some people manage their epilepsy by working out what triggers the seizures and avoiding it e.g. food, flashing lights, lack of sleep or stress.

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