Sudden death in Unverricht-Lundborg patients: is serotonin the key?

Sudden unexpected death in epilepsy (SUDEP) has an incidence of 1–2.5 per 1,000 patient-years and accounts for up 30% of deaths in people with epilepsy [1, 2]. Although knowledge about mechanisms for SUDEP still remains largely unknown, it is well known that risk factors for SUDEP include drug-resistant seizures, symptomatic epilepsy, young age, male gender, long duration of epilepsy, and poor compliance with antiepileptic treatment [1, 2]. Khiari and colleagues [3] recently reported an unusual elevated rate of unexpected deaths in a series of patients with Unverricht–Lundborg disease (EPM1), the most common form of progressive myoclonus epilepsy, associated with mutations in the Cystatin B (CSTB) gene. In particular, 6 out of 19 (31.5%) EPM1 subjects died from SUDEP, independent of seizure control and antiepileptic treatment. However, no specific explanation for this association was provided.