Striatal glucose hypometabolism in preadolescent-onset dentatorubral-pallidoluysian atrophy

Dentatorubral-pallidoluysian atrophy (DRPLA) is hereditary spinocerebellar degeneration presenting various symptoms in association with expansion of the CAG repeat in Atrophin-1 gene. The functional neuroimaging of DRPLA has been poorly investigated. The purpose of this study was to examine 18F-fluorodeoxyglucose-positron emission tomography (18F-FDG-PET) findings of DRPLA. We retrospectively investigated the cases of 14 consecutive genetically confirmed DRPLA patients at our institute. Four juvenile-onset patients underwent 18F-FDG-PET because of intractable seizures. Their 18F-FDG-PET images, clinical profiles and MRI findings were evaluated. For quantitative comparison, 3 healthy volunteers also underwent 18F-FDG-PET as controls. All four patients presented progressive myoclonus epilepsy without MRI abnormalities. Both the visual and quantitative assessments of their 18F-FDG-PET findings demonstrated bistriatal hypometabolism in only the two preadolescent-onset patients with larger CAG repeat size, whereas the two other later-onset patients showed no hypometabolism in the striatum. Bistriatal glucose hypometabolism in preadolescent-onset DRPLA patients might reflect more severe degeneration. This finding could contribute to a better understanding of DRPLA.