Abstracts

Rationale: This study assessed predictors of uptake of genetic testing in families with multiple individuals with epilepsy in an effort to inform appropriate patient-centered approaches to genetic testing in the epilepsies. Methods: Eighty-six individuals (55 with epilepsy and 31 without epilepsy) who were eligible for genetic testing for LGI1, from 21 families with symptoms consistent with autosomal dominant epilepsy with auditory features (ADEAF), completed a self-administered survey and were offered genetic testing. Predictors of uptake were assessed,  including demographic variables (age, sex, employment, and education level), questions regarding total number of lifetime seizures and time since last seizure, testing interest, number of family members with epilepsy, perceived role of genetics in causing epilepsy in their family, and perceived chance of having an epilepsy-related mutation. To assess associations of possible predictors with completion of the testing protocol, we computed prevalence ratios (PRs) using Poisson regression models with generalized estimating equations. Each step of the testing protocol was examined to identify when participants decided not to pursue testing or obtain test results. Results: Among 86 eligible individuals, only 40 (47%) completed testing and received the results. Dropout from the testing protocol largely resulted from failure to return the consent form for pre-test counseling (48%, or 22/46 individuals who dropped out). Interest in testing under a scenario with clinical utility of the test significantly predicted testing uptake (p = 0.002, PR = 7.6), yet only about half (54%) of those who stated they would “definitely or probably” want testing competed the testing protocol. Excluding “don’t know” responses, participants reporting a “high” chance of having an epilepsy-related mutation were significantly more likely than others to complete testing (p = 0.002, PR = 2.2). Among participants with epilepsy, those who had seizures within the last year were more likely to complete testing when total lifetime seizures were included in the model (p = 0.001, PR = 2.0). Uptake of testing did not differ between individuals with and without epilepsy, and while none of the demographic variables significantly predicted uptake; younger individuals were more likely to complete testing (< 40 (57%), 40-59 (49)%, ≥60 (36%), p=0.31). Conclusions: Findings from this study of families containing multiple individuals with epilepsy suggest that testing interest, perceived mutation status, and recent seizure occurrence significantly predicted uptake for LGI1 testing. However, uptake of testing was considerably lower than stated interest.  Genetic counselors and other health care professionals should be mindful of these findings when taking a patient-centered approach to genetic testing and assisting in decision-making. Funding: This research was supported by R01 NS078419.