US researchers have unveiled a new study - the Epilepsy Phenome/Genome Project (EPGP) - to try and pinpoint the genetic and environmental factors that contribute to epilepsy and explain why some people respond differently to epilepsy medicine. The study, both the first and the largest of its kind, is being funded by the National Institutes of Neurological Disorders and Stroke, who are partnering with clinicians, affected families and epilepsy advocates around the country for this five-year study.
Approximately 50 million people worldwide experience regular seizures, making epilepsy one of the most common neurological disorders, according to World Health Organisation figures. Epilepsy can be triggered a brain injury or disease, but in approximately 60 per cent of cases the cause of the epilepsy is unknown. In some cases the condition runs in families, suggesting that genes may play a part.
Epilepsy is caused by a sudden burst of excess electrical activity in the brain, disrupting the normal electrical messages passing between brain cells and triggering a seizure. There are a wide variety of different epileptic syndromes, characterised by the age of onset, the type of seizure (e.g. localised to one part of the brain or throughout), the presence or absence of detectable brain disease and genetic background. However, very little is known about the genetic and environmental components that underlie these different types.
Furthermore, although 70 per cent of epilepsy cases can be successfully treated with anti-epileptic drugs (AEDs), most individuals suffer from unwanted side-effects, ranging from weight-gain, sleepiness and disorientation, to lowered efficacy of the contraceptive pill and harm to an unborn baby. A further three in ten epileptics cannot become seizure-free with current treatments.
In the hunt for genes linked to epilepsy, the EPGP hopes to compare the genomes of 3750 people who have epilepsy and also have a sibling with the condition, to 3000 healthy controls. Detailed clinical information will also be collected in order to try and uncover any environmental contributors. The researchers hope that the study will lead to better diagnosis of epilepsy and, new and more targeted treatments for people living with seizures.