L-dopa-responsive Parkinson's syndrome in association with phenylketonuria: In vivo dopamine transporter and D2 receptor findings

Abstract

Reports of parkinsonism in phenylketonuria are exceedingly rare. We report on a patient who had received a delayed diagnosis of phenylketonuria as an infant and subsequently developed levodopa-responsive parkinsonism at the age of 33. Single-photon emission computed tomography (SPECT) using 123I-FP-CIT ([123)I]-2 beta-carbo-methoxy-3beta-(-4-iodophenyl -N-(3-fluoropropyl)-nortro-pane) used to measure dopamine transporter levels on two occasions, 7 and 9 years after the onset of neurological symptoms, were normal. Iodine-123-iodo-lisuride SPECT (IBZM) imaging, however, showed reduced caudate over putamen binding. This combination of imaging findings indicates a possible upregulation of postsy..