Largest ever genetic study of epilepsy provides new insights

The largest genetic study of its kind, coordinated by the International League Against Epilepsy (ILAE), has discovered specific changes in our DNA that increase the risk of developing epilepsy. This research, published in the journal Nature Genetics, greatly advances our knowledge of why epilepsy develops and may inform the development of new treatments for the condition.

Epilepsy, a common brain disorder in which nerve cell activity in the brain is disturbed, is known to have genetic components and sometimes runs in families. In the new study, researchers compared the DNA from almost 30,000 people with epilepsy to the DNA of 52,500 people without epilepsy. The differences highlighted areas of our DNA that might be involved in the development of the disorder.

The researchers identified 26 distinct areas in our DNA that appear to be linked to epilepsy, including 19 that are specific to a particular form called ‘genetic generalised epilepsy’ (GGE). They were also able to point to 29 genes that are probably contributing to epilepsy within these DNA regions.

The scientists found that the genetic picture was quite different when comparing distinct types of epilepsy — in particular, when ‘focal’ and ‘generalised’ epilepsies were compared — providing clues as to why different epilepsy syndromes exist. The results also suggest that proteins that carry electrical impulses across the gaps between neurons in our brain make up some of the risk for generalised forms of epilepsy.

“Gaining a better understanding of the genetic underpinnings of epilepsy is key to developing new therapeutic options, and consequently a better quality of life, for the over 50 million people globally living with epilepsy,” said study co-leader Gianpiero Cavalleri, a Professor at RCSI University of Medicine and Health Sciences and Deputy Director of the SFI FutureNeuro Research Centre.

The researchers also showed that many of the current medications for epilepsy work by targeting the same epilepsy risk genes that were highlighted in this study. Based on their data, the researchers were able to propose some potentially effective alternative drugs that are normally used for other conditions, but are known to target some of the other epilepsy risk genes uncovered.

“This identification of epilepsy-associated genetic changes will allow us to improve diagnosis and classification of different epilepsy subtypes,” said co-author Professor Colin Doherty, a clinical investigator at the SFI FutureNeuro Centre. “This in turn will guide clinicians in selecting the most beneficial treatment strategies, minimising seizures.”

Over 150 researchers based across Europe, Australia, Asia, South America and North America carried out the research, working together as part of the ILAE Consortium on Complex Epilepsies. The consortium was formed by researchers in 2010, recognising that the complexity of genetic and environmental factors underlying epilepsy would require research across massive datasets, and therefore unprecedented collaboration on an international scale.

“This is a major milestone for the ILAE Consortium on Complex Epilepsies, demonstrating what can be achieved when scientists openly collaborate and share data from across the world,” said ILAE President Professor Helen Cross. The results have enabled the researchers to bookmark parts of the genome that should be the focus of future epilepsy research, and are expected to form the basis for further work looking at the molecular pathways involved in seizure generation, neuronal dysfunction and altered brain activity.

Image credit: iStock.com/Gilnature