Epilepsy Is a Key Feature of Pediatric-Onset Huntington’s Disease
Abstract number :
3.416
Submission category :
18. Case Studies
Year :
2023
Submission ID :
1075
Source :
www.aesnet.org
Presentation date :
12/4/2023 12:00:00 AM
Published date :
Authors :
Presenting Author: Dawn Lammert, MD, PhD – Johns Hopkins University School of Medicine
Jee Bang, MD, MPH – Assistant Professor, Neurology, Johns Hopkins University School of Medicine; Carl Stafstrom, MD, PhD – Professor, Neurology, Johns Hopkins University School of Medicine
Rationale: Seizures can be a presenting symptom of pediatric-onset Huntington’s disease (PoHD). Epilepsy occurs in up to 50% of children with PoHD. This is in stark contrast to adult-onset HD where the frequency of seizures is similar to the general public. Epilepsy in PoHD is underappreciated by pediatric neurologists and epileptologists. We present a case report and review of the literature on epilepsy in PoHD to increase awareness and highlight important areas of future research.
Methods: Chart review and review of available literature on epilepsy in PoHD was conducted. Parent consent was obtained.
Results: A 10-year-old boy with a history of language delay, oral motor dysfunction, and developmental regression presented with a first lifetime seizure. Initial routine electroencephalogram (EEG) showed parietal-occipital spike-and-slow wave complexes. Magnetic resonance imaging demonstrated caudate atrophy. A pathogenic allele with 88 repeats, diagnostic for PoHD, was anticipated from his father’s allele with 44 repeats. The boy was started on levetiracetam, but he eventually required addition of valproic acid to control his seizures. Over time, history alone could not differentiate abnormal movements from seizures. Overnight continuous video EEG monitoring in the epilepsy monitoring unit (EMU) demonstrated epileptic myoclonic jerks, worse with awakening. His EEG also demonstrated bursts of poly-spike and wave with no clear clinical correlation. Clobazam was added nightly to target both disordered sleep and myoclonic jerks.
Conclusions: HD is caused by CAG trinucleotide expansion in exon 1 of the HTT gene, and anticipation is more likely to occur when the pathogenic allele is paternally inherited, as in our patient. Adults typically present with cognitive or functional decline followed by motor symptoms, including chorea. In contrast, children present with declining school performance, abnormal behavior, oral motor dysfunction, rigidity, gait difficulties, and seizures. As the disease progresses, the EEG and seizure types may change, and seizures can become medication refractory. However, the natural history of epilepsy in PoHD is incompletely understood, and the pathophysiology of seizures in PoHD is an area of active research. Valproate is the most common medication reported, but with newer generations of anti-seizure medications, understanding current provider practices will be helpful. As demonstrated by our case, continuous video EEG monitoring is a key tool for differentiating a movement disorder from seizure, and an EMU stay can be helpful to monitor medication tolerability, efficacy, and effects on comorbidities such as sleep, balance, and mobility. Overall, epilepsy is an underappreciated feature of PoHD but is important for epileptologists to recognize.
Funding: None.
Case Studies