title: 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 (123)I-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.
authors.affiliation: Reta Lila Weston Institute of Neurological Studies, University College London, United Kingdom.
authors.forename: Andrew H
authors.initials: AH
authors.lastname: Evans
authors.forename: Durval C
authors.initials: DC
authors.lastname: Costa
authors.forename: Sveto
authors.initials: S
authors.lastname: Gacinovic
authors.forename: Regina
authors.initials: R
authors.lastname: Katzenschlager
authors.forename: John D
authors.initials: JD
authors.lastname: O'sullivan
authors.forename: Simon
authors.initials: S
authors.lastname: Heales
authors.forename: Phillip
authors.initials: P
authors.lastname: Lee
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Lees
mesh_terms: D000328:Adult; D000978:Antiparkinson Agents / Q000627:therapeutic use; D001549:Benzamides; D001921:Brain / Q000098:blood supply / Q000000981:diagnostic imaging; D050483:Dopamine Plasma Membrane Transport Proteins; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes; D007980:Levodopa / Q000627:therapeutic use; D008562:Membrane Glycoproteins / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D010300:Parkinson Disease / Q000150:complications* / Q000188:drug therapy / Q000378:metabolism*; D010661:Phenylketonurias / Q000150:complications*; D011759:Pyrrolidines; D019275:Radiopharmaceuticals; D017448:Receptors, Dopamine D2 / Q000378:metabolism*; D015899:Tomography, Emission-Computed, Single-Photon; D014326:Tropanes
chemical_list: D000978:Antiparkinson Agents; D001549:Benzamides; D050483:Dopamine Plasma Membrane Transport Proteins; D007457:Iodine Radioisotopes; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D011759:Pyrrolidines; D019275:Radiopharmaceuticals; D017448:Receptors, Dopamine D2; D014326:Tropanes; C087552:2-carbomethoxy-8-(3-fluoropropyl)-3-(4-iodophenyl)tropane; D007980:Levodopa; C055743:3-iodo-2-hydroxy-6-methoxy-N-((1-ethyl-2-pyrrolidinyl)methyl)benzamide