Familial occurrence of seizure disorders across MRI defined structural focal epilepsy etiology.

BACKGROUND: Previous studies have established familial occurrence of epilepsy and seizure disorders and early age of epilepsy onset as predictors of genetic epilepsy, but have not evaluated the rate of their occurrence in patients with different epilepsy etiology. Our study determines the distribution of familial occurrence and age of epilepsy onset across structural focal epilepsy (FE) etiology in a large FE cohort.

METHODS: Records of 1354 consecutive patients evaluated for epilepsy and seizure disorders in The Neurology Clinic, University Clinical Center of Serbia from 2008 to 2019 were screened for FE. Structural etiology, lobar diagnosis, familial occurrence, and age at epilepsy onset were determined. Patients with a. nonlesional focal epilepsy (NLFE), b. hippocampal sclerosis (HS) and c. congenital or perinatal etiology (CPE) were classified as NAFE, while patients with an identified acquired focal epilepsy (AFE) constituted the control group.

RESULTS: We identified 965 patients with FE, 329 (34.1 %) with NLFE, 213 (22.1 %) with HS, 174 (18.0 %) with CPE and 249 (25.8 %) with AFE. Familial occurrence was identified in 160 (16.6 %), 19.1 % of patients with NAFE and 9.2 % of AFE (p = 0.003). Patients with NAFE had a younger age of epilepsy onset (13 vs. 18 years, p < 0.001). The highest proportion of familial occurrence was found in patients with NLFE (23.7 %), while the youngest median age of epilepsy onset was identified in patients with HS (12 years) and CPE (11 years).

CONCLUSION: Patients with NAFE frequently have familial occurrence of epilepsy and have an earlier age of epilepsy onset than patients with AFE.