Breaking Epilepsy’s Genetic Code

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Genetic tests could improve diagnosis and treatment in patients with unexplained epilepsy.
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Most cases of epilepsy are believed to be the result of a variety of genetic alterations combined with environmental factors.

Our bodies depend on electricity. Electrical signals are crucial for your heart to beat, and the electrical activity in your brain enables you to read and understand this sentence. When the electrical signaling goes awry, major health issues can arise.

Epilepsy is a neurological disorder characterized by recurrent surges of abnormal electrical activity in the brain that produce seizures. The cause of the surges is not well understood; however, researchers have shown that it can involve genetics, head trauma, developmental disorders, prenatal brain damage and infections.

Accurately diagnosing the cause of seizures is necessary for prescribing the best treatments. Despite this, in almost half of those affected by epilepsy, the cause of seizures is unknown.

Krembil Clinician Investigator Dr. Danielle Andrade recently examined the utility of a genetic test to help determine the cause of unexplained epilepsy in adults with intellectual disability (ID). The test detects a type of genetic alteration known as copy number variation (CNV), which has been linked to other diseases.

Dr. Andrade and her colleagues performed the genetic test on 143 adults and interpreted the results in the context of each patient’s clinical features. They found that a high proportion (16%) of these patients carried rare CNVs that contributed to their epilepsy. Of the CNVs identified, eight were found to affect genes previously implicated in ID, autism and/or epilepsy. Moreover, the researchers pinpointed five altered genes that most likely contributed to patients’ clinical features.

"This study shows that genetic testing could provide clinicians with important information that may improve the diagnosis and treatment of epilepsy. Adults with epilepsy of unknown cause should be re-investigated with the modern DNA technologies available today”, says Dr. Andrade.

This work was supported by the Ontario Brain Institute, the Government of Ontario and the Toronto General & Western Hospital Foundation. A Bassett holds a Tier 1 Canada Research Chair in Schizophrenia Genetics and Genomic Disorders.

Borlot F, Regan BM, Bassett AS, Stavropoulos DJ, Andrade DM. Prevalence of Pathogenic Copy Number Variation in Adults With Pediatric-Onset Epilepsy and Intellectual Disability. JAMA Neurol. 2017 August 28. doi:10.1001/jamaneurol.2017.1775