Brain glucose metabolism was measured in two children with early-onset Huntington's disease, using positron emission tomography with fluorodeoxyglucose (FDG) as the tracer. A marked (48%) hypometabolism was found at the level of the caudate nuclei, but other areas of the brain, particularly the cerebral cortex, were not significantly affected. Despite its different clinical presentation, Huntington's disease in children is characterized by brain metabolic alterations similar to those found in adult patients.