An international group of scientists, led by a team at the Columbia University Medical Centre, has found the first gene linked to the most common type of childhood epilepsy, rolandic epilepsy (RE).

RE develops between the ages of 3 and 12 years. Seizures originate from the rolandic area of the brain, which controls body movement, and usually start in the morning just after the child wakes up. There is typically tingling and loss of movement on one side of the face and speech is often affected. The seizures stop of their own accord after several minutes, and most children grow out of the disorder by adolescence.

The researchers (above) examined the genes of 38 families, in which one or more members were affected by RE. Using advanced analysis techniques, they found a region on a specific chromosome that was linked to RE. The team then compared this region in people with RE, to a control group who didn't have the condition (255 people in total). In this way they managed to pinpoint the culprit gene, which is known as ELP4.

When the team's Canadian members repeated the experiment with a different set of families and controls, they got the same results.

The findings now need to be replicated by researchers who are not in the international team described (to exclude bias); however these two independent experiments provide strong evidence that ELP4 is linked to RE.

ELP4 has never been linked to a human disease before, but is related to a group of genes that have recently been associated with other common forms of epilepsy. These genes appear to influence the organization of brain circuits.

The discovery of genes such as ELP4 has changed the way in which epilepsy is viewed. Whereas it was previously thought be caused by a fault in the brain's ion channels, it is now believed to stem from neuronal connections made during development.

Children with other conditions, such as attention deficit and hyperactivity disorder (ADHD), have a similar pattern of brain activity as those with RE. It is therefore possible that ELP4 is the faulty gene in all these disorders, which might explain why children with epilepsy often have learning and behavioural problems.

These findings are very exciting, not only for the understanding of epilepsy, but of several other neurological conditions. The next step is to find out precisely how the ELP4 gene affects brainwave activity. Once this has been established, interventions that treat a spectrum of disorders could potentially be developed.

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