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

Authors

  • Andrew H. Evans FRACP,

    1. Reta Lila Weston Institute of Neurological Studies, University College London
    2. The National Hospital for Neurology and Neurosurgery, Queen Square, London, United Kingdom
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  • Durval C. Costa MD, PhD, FRCR,

    1. Director Clinico, HPP Medicina Molecular, SA, Porto Portugal
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  • Sveto Gacinovic MD,

    1. Institute of Nuclear Medicine, UCL Medical School, Middlesex Hospital, London
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  • Regina Katzenschlager MD,

    1. Reta Lila Weston Institute of Neurological Studies, University College London
    2. The National Hospital for Neurology and Neurosurgery, Queen Square, London, United Kingdom
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  • John D. O'Sullivan MD,

    1. Department of Neurology, Royal Brisbane Hospital, Herston, Queensland, Australia
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  • Simon Heales PhD, FRCPath,

    1. Neurometabolic Unit, The National Hospital for Neurology and Neurosurgery, Queen Square, London, United Kingdom
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  • Phillip Lee,

    1. Charles Dent Metabolic Unit, The National Hospital for Neurology and Neurosurgery, Queen Square, London, United Kingdom
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  • Andrew J. Lees MD, FRCP

    Corresponding author
    1. Reta Lila Weston Institute of Neurological Studies, University College London
    2. The National Hospital for Neurology and Neurosurgery, Queen Square, London, United Kingdom
    • Reta Lila Weston Institute of Neurological Studies, Windeyer Building, 46 Cleveland Street, London W1T 4JF
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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-carbomethoxy-3beta-(-4-iodophenyl)-N-(3-fluoropropyl)-nortropane) 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 postsynaptic D2 receptors in the context of intact presynaptic dopamine nerve terminal density. © 2004 Movement Disorder Society

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