A possible role of Apolipoprotein E in Idiopathic Generalized Epilepsy

Idiopathic generalized epilepsy (IGE) represents a heterogeneous group of syndromes covering roughly 15 %-20 % of all epilepsies. It is believed to be a complex and polygenic disorder with numerous worldwide identified rare variants in several genes. Previously identified variants failed to fully explain the etiology and phenotypic heterogeneity. ApoE gene polymorphisms have been largely investigated in focal epilepsies but rarely in IGEs. Our objective is to investigate the frequency and role of ApoE polymorphisms in IGE syndromes. We enrolled a cohort of patients with confirmed IGE syndromes, followed in the neurology department of RAZI University hospital in Tunisia, and performed ApoE genotyping using a PCR-RFLP technique. A total of 120 patients were selected for the molecular study. E3/E3, E3/E4 and E2/E3 genotype frequencies were 79.2 %, 10.8 % and 10 % respectively. E3/E4 genotype carriers developed the disease 3 years earlier than E3/E3 carriers (p = 0.034). Additionally, a significant association was found between the E3/E4 genotype and female patients (p = 0.02). Psychiatric symptoms were more frequent in patients with Generalized Tonic-Clonic Seizures Alone and Juvenile Myoclonic Epilepsy (JME) compared to those with absence epilepsy (p = 0.01). Our findings, also, highlighted the significant association between ApoE E4 allele and earlier age of onset of IGE. These results underscore the importance of accurate diagnosis and management strategies for patients with IGE syndromes and their at-risk relatives with a particular attention for female patients.