FDG-PET findings and alcohol-responsive myoclonus in a patient with Unverricht-Lundborg disease

The aim of this report is to describe clinical, EEG, and neuroimaging findings in a patient with Unverricht-Lundborg disease (ULD), the most common form of progressive myoclonus epilepsy (PME). A 23-year-old male with genetically confirmed ULD had a phenotype consisting of myoclonus, generalized seizures, intellectual disability, ataxia, and dysarthria. Myoclonus and gait disturbance were strongly ameliorated by alcohol consumption. EEG revealed a posterior dominant rhythm with alpha variant, mild bilateral slowing, and anterior-predominant epileptiform abnormalities. Brain MRI showed mild cerebellar atrophy. FDG-PET revealed hypometabolism more prominent in the posterior brainstem, thalami, frontal and parietal lobes. This report confirms that alcohol may ameliorate myoclonus in a subset of patients with PME, including genetically confirmed ULD. In addition, the presence of FDG-PET hypometabolism predominant in the frontoparietal region and thalami has not been previously described in ULD, yet is consistent with previous brain morphometry studies showing motor cortex and thalamic atrophy in ULD, and brings into question the possibility of a shared metabolic pattern with other PMEs, notably Lafora disease.