PET analysis of a case of cerebrotendinous xanthomatosis presenting hemiparkinsonism

We describe a 34-year-old Japanese woman presenting gait difficulty and Achilles tendon swelling. The patient was diagnosed as having cerebrotendinous xanthomatosis (CTX) based on the high serum cholestanol level and diminished enzymatic activity of 27-hydroxylase of fibroblasts from her skin. Her clinical presentation was atypical regarding the presence of hemiparkinsonism and absence of apparent cataract, dementia, and cerebellar ataxia. Although MRI studies could not detect any abnormality in the basal ganglia or midbrain, PET analysis using [18F]-6-fluoro-L-dopa revealed reduced uptake of dopamine into the putamen, suggesting the impairment of presynaptic dopaminergic neurons.