B.06: Two definite sudden unexpected deaths in epilepsy in a family with a DEPDC5 mutation

Abstract

Background:DEPDC5 gene, mapped to 22q12.2-q12.3, has been associated with a variety of familial epilepsies, including FFEVF, autosomal dominant nocturnal frontal lobe epilepsy, and familial TLE. Notably, DEPDC5 has never been linked to increased risk of sudden unexpected death in epilepsy (SUDEP). Methods: Cases review. Results: We studied a three-generation, non-consanguineous, French-Canadian family with nine clinically affected individuals. The index case is a 39-year-old man who started having seizures (as 2rily GTCS) at the age of 13 years. EEGs showed interictal discharges over the right anterior-temporal region. Brain MRI was unremarkable. Two individuals in this family suffered definite autopsy-confirmed SUDEP, at the ages of 58 and 50 years, respectively. Overall, seizure-history in this family can be summarized by an onset before reaching adulthood followed by subsequent progressive decrease in seizure frequency. Seizures were predominantly nocturnal 2rily GTC. Genetic analysis revealed a pathogenic heterozygous variant in the DEDPC5 gene (p.Gln216, c.646C>T), which results in a premature stop codon, in all affected family members plus on heatlhy relative. Importantly, all the subjects were cognitively intact, and there was no history of cardiac symptomatology/cardiovascular risk factor. Conclusions: The finding in this family suggests that DEPDC5 mutations may be a risk factor for SUDEP.