Somatic mutations causing focal epilepsy identified using purified neuronal nuclei from stereo-EEG electrodes
Patients with epilepsy have recurrent seizures that lead to injuries, social issues, job and driving restrictions and even death. The cause of epilepsy is often unknown but recent studies have suggested that genetic changes in brain cells that are not inherited but occur during fetal development can cause epilepsy. As these genetic changes in the brain are not present in other body cells, we could previously only examine brain tissue after a patient had surgery. Epilepsy surgery can be done if patients do not become seizure free with anti-seizure drugs. In some patients, a special recording with electrodes inside the brain is needed to find out if surgery is possible. This recording also helps to decide which part of the brain can be removed during surgery. After the recording is completed, the electrodes are removed. We have developed a technique to collect cells from these electrodes and sort out only the brain cells. We then examine these cells for variants that cause epilepsy. As the electrodes are implanted in many brain regions, we can also compare abnormal and healthy brain areas. This is much better than only looking at brain tissue after surgery with no healthy areas to compare.
We look for genetic variants in brain cells in 18 patients with epilepsy using our novel technique. This will tell us more about the involved genes which will help to better understand epilepsy and develop better treatments in the future. Our innovative technique could also routinely be used in patients who have recordings from electrodes in the brain as understanding the brain regions that carry genetic variants may help to make better decisions about the surgery.
Karl Klein , University of Calgary
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