Global study finds common form of epilepsy linked to genetics

People with mesial temporal lobe epilepsy (MTLE) carry an increased number of rare mutations in specific genes, according to a new study published in Annals of Neurology.

The study, which is the result of an international collaboration involving leading centres across Australasia, Europe and North America including the Comprehensive Epilepsy Programs at Austin Health and The Royal Melbourne Hospital, investigated whether rare genetic mutations influence surgical outcomes in patients with MTLE.

The results found that compared to more than 8000 people without epilepsy who served as ‘controls’, 196 people with MTLE had a higher frequency of rare changes in specific genes, including genes involved in epilepsy.

However, these changes did not differ between people with MTLE who had a good outcome after epilepsy surgery and those who did not.

These results indicate that rare gene mutations are unlikely to play a major role in the failure of surgery for MTLE.

University of Melbourne Associate Professor Piero Perucca, a lead researcher on the study, said these findings challenge the common notion of what causes MTLE and could change the way patients are managed.

“MTLE is one of the most common forms of epilepsy and has historically been considered a ‘non-genetic’ disorder caused by brain injuries such as infections, trauma, or damage occurring around birth”.

Mesial temporal lobe epilepsy (MTLE) is characterised by seizures that often do not respond to medications.

People with seizures resistant to medication have a poor quality of life due to many factors, including adverse effects of medications, psychiatric and neuropsychological comorbidities, social and employment restrictions, and stigma. Uncontrolled seizures also carry a risk of premature death.

Focal epilepsy (characterised by seizures starting in one part of the brain) accounts for about 60 per cent of all epilepsy cases.

“We now know that rare changes in specific genes do contribute to MTLE, and we can explain this to our patients”, Professor Perucca said.

“The finding that these rare changes do not have a major influence on the outcome of surgery for MTLE should be reassuring to patients and their families, as well as their physicians when considering surgery”.