Gene for epilepsy paves way for genetic testing

Researchers in Australia have identified a genetic link to a common form of epilepsy, which could lead the way to genetic testing for this type of the condition.

An international team of scientists led by Professor Ingrid Scheffer at the Florey Institute of Neuroscience and Mental Health in Melbourne, Australia, found a gene mutation linked to focal epilepsy. In an interview broadcast on ABC news, Professor Scheffer said the findings were 'paradigm shifting'.

One in 100 people are affected by epilepsy. There are many different forms of epilepsy, but approximately 60 percent of those affected have focal epilepsy or partial epilepsy, where the seizures originate from one part of the brain, reports ABC news.

It is thought that this type of epilepsy is caused by neurological trauma such as a brain injury or tumours but for many people the precise cause is unknown. Professor Scheffer explains: 'Instead of saying "we don't know the cause", they can test for this gene'.

Genetic factors are known to play a role in epilepsy and around 25 genes for rarer types of epilepsy have already been identified, reports News.com.au. Professor Scheffer explains genetic screening will be beneficial in cases where everything else in the brain looks normal. 'If you have focal epilepsy and there is no cause known, then this gene should be tested to look for a mutation', she said. 'It will give you a cause. That has important implications in terms of genetic counselling and managing the risk to your own offspring'.

In total, 90 families participated in the study which used a method of exome sequencing and as a result detected a mutation in the DEPDC5 gene on chromosome 22 in 12 percent of families with familial focal epilepsies. The researchers state the findings present the mutation as the common cause of familial focal epilepsies.

'If you have this gene, you have a 60 percent to 70 percent chance of having epilepsy', Professor Scheffer explained. 'If you don't have seizures and you do have this gene, you can still pass on your risk to the child'.

The researchers suggest that the DEPDC5 gene plays a role in the way neurons in the brain receive signals from other neurons and cells. However, its biological role and influence on focal epileptic seizures is yet to be fully understood.

The results of this study may offer new opportunities in diagnosing epilepsy, potentially better targeted treatments and genetic advances. Professor Sanjay Sisodiya, head of genetics at Epilepsy Society, a UK charity, said: 'The discovery may cast light on mechanisms that might more be of more general interest'.

'[The study] is especially interesting as mutations in the same gene appear to be able to cause more than one type of familial epilepsy. The challenge now is to understand how this happens'.

The study was published in the journal Nature Genetics.