From Genetic Testing to Precision Medicine in Epilepsy.

Epilepsy includes a number of medical conditions with recurrent seizures as common denominator. The large number of different syndromes and seizure types as well as the highly variable inter-individual response to the therapies makes management of this condition often challenging. In the last two decades, a genetic etiology has been revealed in more than half of all epilepsies and single gene defects in ion channels or neurotransmitter receptors have been associated with most inherited forms of epilepsy, including some focal and lesional forms as well as specific epileptic developmental encephalopathies. Several genetic tests are now available, including targeted assays up to revolutionary tools that have made sequencing of all coding (whole exome) and non-coding (whole genome) regions of the human genome possible. These recent technological advances have also driven genetic discovery in epilepsy and increased our understanding of the molecular mechanisms of many epileptic disorders, eventually providing targets for precision medicine in some syndromes, such as Dravet syndrome, pyroxidine-dependent epilepsy, and glucose transporter 1 deficiency. However, these examples represent a relatively small subset of all types of epilepsy, and to date, precision medicine in epilepsy has primarily focused on seizure control, and other clinical aspects, such as neurodevelopmental and neuropsychiatric comorbidities, have yet been possible to address. We herein summarize the most recent advances in genetic testing and provide up-to-date approaches for the choice of the correct test for some epileptic disorders and tailored treatments that are already applicable in some monogenic epilepsies. In the next years, the most probably scenario is that epilepsy treatment will be very different from the currently almost empirical approach, eventually with a "precision medicine" approach applicable on a large scale.