Treating seizures in SYN1-related epilepsy: a systematic review.

INTRODUCTION

Synapsin1-related epilepsy is a rare entity, in which patients typically present reflex seizures, provoked by contact with water. Moreover, patients carrying a pathogenic variant of the synapsin 1 gene (SYN1) can present developmental delay, behavior disorders, and other types of seizures. While SYN1-related epilepsy becomes better characterized, there is still no consensus on the appropriate antiseizure medication (ASM) to use.

MATERIALS AND

METHODS

To compare ASMs efficacies in this particular syndrome, we performed a systematic literature review according to the PRISMA guidelines by using PubMed and Embase databases. All the studies reflecting the seizure outcome associated with the treatment of SYN1-related epilepsy were included in the present review, except those that were not written in English or were in the forms of poster, commentary, or conference abstract.

RESULTS

Eight studies and a total of 52 patients with well-documented treatment were retrieved from the literature. The most frequently used ASMs were valproic acid (VPA) (58 %), lamotrigine (LTG) (35 %) and carbamazepine (CBZ) (35 %). Regarding seizure-free patients, the most effective ASMs were lacosamide (LCM) (50 %), oxcarbazepine (OXC) (44 %) and CBZ (38 %). When considering seizure-freedom or significant (≥ 50 %) seizure reduction, the best treatment is LTG (63 %), followed by LCM (50 %) and CBZ (50 %). LTG, CBZ, OXC and LCM seem to be associated with a more favorable seizure outcome compared to levetiracetam (LEV) or VPA, with a statistically significant difference in terms of seizure reduction (p = 0.028) and seizure freedom for patients carrying a non-truncating variant (p = 0.047).

CONCLUSION

Based on our systematic literature review, patients with SYN1-related epilepsy show better seizure frequency reduction when treated with LCM, LTG, CBZ, or OXC, compared to VPA and LEV, despite VPA being the most prescribed anti-seizure medication for this syndrome. Hence, sodium channel blockers appear to represent the best therapeutic option for these patients.