How genetic testing can contribute to epilepsy management

As sequencing costs decrease and the clinical relevance of genetics increases, genomic data have now entered the everyday clinical practice of epilepsy management. Therefore, specialists should be able to interpret genetic data and use them to make treatment decisions, argued Dr Guido Rubboli (University of Copenhagen, Denmark) [1].

Applying genetics may contribute to prognosis and improve treatment. It allows for choosing treatments that correct specific metabolic defects, to avoid adverse events that can aggravate the pathogenic defect, and to select anti-epileptic drugs (AEDs) that counteract the functional disturbance caused by a gene mutation. Mutations in SCN1A, SCN1B, SCN2A, SCN3A, SCN8A, and SCN9A are responsible for a considerable proportion of drug-resistant epilepsy cases with childhood onset. Phenotypic variability can be associated with a single gene and even a single variant. Detailed (“deep”) clinical phenotyping may identify subtle or unexpected distinguishing features of specific genes that can help to identify the underlying genetic mechanisms.

Genetic testing for therapeutic decision-making is not only useful in children, but also in adults with epilepsy, as a study by Rubboli and colleagues illustrated [2]. Participants were 200 patients from 18-80 years. A genetic diagnosis could be established in 46/200 patients (23%). SCN1A, KCNT1, and STXBP1 accounted for 48% of positive findings. Consequently, gene-specific treatment changes were initiated in 11/46 patients (17%), of which 10 with SCN1A. Ten of 11 patients improved either in terms of seizure reduction and/or an increased alertness and general well-being.

Performing genetic testing allows for offering genetic counselling to patients. Genetic counselling is in fact recommended by the International League Against Epilepsy (ILEA) as standard care for all infantile seizures and epileptic encephalopathies.

1. Rubboli G. Session FW16, EAN 2020.
2. Johannesen KM, et al. Epilepsia 2020;00:1-6.

 



Posted on 9 September, 202028 October, 2020