Perampanel attenuates myoclonus in a patient with neuronal ceroid lipofuscinoses type 2 disease

Neuronal ceroid lipofuscinoses type 2 disease (CLN2) is a very rare, autosomal recessive neurodegerative disease caused by deficient activity of the enzyme tripeptidyl peptidase 1 (TPP1). The seizures in CLN2 are polymorphic and resistant to antiepileptic drugs. In particular, myoclonus (epileptic and non-epileptic) predominant as the disease progresses. Herein, we present a child of CLN2 disease, who had near-continuous myoclonus, and was subsequently attenuated by administration of Perampanel. This girl had initially presented with language delay and generalized tonic clonic seizure at 3 years of age. The diagnosis of CLN2 was made via genetic study, which showed compound heterozygous mutation on TPP1 gene (c.622 C > T and partial gene deletion including at least exons 1-3). Currently, at the age of 8 years, there was near-continuous myoclonus (epileptic and non-epileptic), which worsen during acute illness. Eventually, she was given Perampanel with starting dose of 1 mg/day and slowly titrated upto 6 mg/day in 4 weeks. There was significant attenuation of myoclonus (>50% seizure reduction). To our knowledge, this is the first case in the literature describing the efficacy of perampanel in treating myoclonus in CLN2 disease.