A heterozygous rare variant in causes epilepsy and levetiracetam-induced drug-resistant status epilepticus.

encodes a neuronal synaptic vesicle glycoprotein essential for neurotransmitter release. Altered SV2A function leads to epilepsy in animal models, yet only two reports of human variants have linked to syndromic drug-resistant epileptic encephalopathies and epilepsy. SV2A is also the binding site for the commonly used antiseizure medication levetiracetam (LEV). However, information about how rare variants influence LEV response is lacking. Here, we report a two-year-old child with new-onset epilepsy found to have a heterozygous rare variant in (NM_014849.5:c.1978G>A;p.Gly660Arg) who developed refractory status epilepticus after escalation of LEV treatment for initial baseline seizure control. This report provides additional evidence that monoallelic pathogenic variants cause epilepsy and that genetic variation in could lead to paradoxical seizure worsening when treated with LEV.