Dopa-responsive dystonia and early-onset Parkinson's disease in a patient with GTP cyclohydrolase I deficiency?



We describe a patient with a combination of dystonic and parkinsonian signs. Paraclinical studies revealed a mutation in the GTP cyclohydrolase I gene (GCH1) and a decrease in [123I]-N-ω-fluoropropyl-2β-carbomethoxy-3β-(4-iodophenyl) nortropane (123I-FP-CIT) binding ratios indicative of Parkinson's disease. We conclude that the patient probably suffers from a variant of dopa-responsive dystonia (DRD) or two separate movement disorders, normally considered to be differential diagnoses, DRD and early-onset Parkinson's disease with resulting difficulties concerning treatment and prognosis. © 2005 Movement Disorder Society