Pearls & Oy-sters: Epilepsy Is a Key Feature of Pediatric-Onset Huntington Disease

Pediatric-onset Huntington disease (PoHD) presents differently from adult-onset disease. Children typically exhibit regression in school performance, psychiatric features such as inattention, and oral motor dysfunction. Unlike adult-onset HD, in which seizures occur at approximately the rate of the general public, at least half of children with HD develop epilepsy, and seizures can be a presenting feature of PoHD. Here we present the case of a 10-year-old boy with a history of language delay, motor regression, oral motor dysfunction, and tremor who presented with a first lifetime seizure. Given a family history of Huntington disease in his father, PoHD was considered, and a pathogenic allele with 88 repeats was confirmed in the child. As symptoms progressed, history alone could not differentiate abnormal movements from seizures. Continuous video electroencephalography helped to demonstrate epileptic myoclonic jerks and guide treatment.