Biochemical and fluorodopa positron emission tomographic findings in an asymptomatic carrier of the gene for dopa-responsive dystonia.

We report cerebrospinal fluid monoamine metabolite analyses and 6-[18F]fluoro-1-dopa positron emission tomography (FD-PET) from an asymptomatic carrier of the gene for dopa-responsive dystonia. Cerebrospinal fluid homovanillic acid, tetrahydrobiopterin, and neopterin concentrations were reduced in this man and in his affected children. His FD-PET was normal, as we have previously found in dopa-responsive dystonia. Neurological function and FD-PET may be normal despite marked abnormality in dopamine metabolism.