title: Dopamine transporter gene polymorphism, spect imaging, and levodopa response in patients with Parkinson disease.
abstract: OBJECTIVE
  To assess the potential association between dopamine transporter (DAT) genotype, single photon emission CT (SPECT) measures using [123I]-N-omega-fluoropropyl-2beta-carbomethoxy-3beta-(4-iodophenyl)nortropane ([123I]-FP-CIT) of striatal dopaminergic function, and oral levodopa response pattern in a cohort of patients with Parkinson disease.
  
  
  METHODS
  Thirty-six patients at different disease stages enrolled in the study. Each patient was examined by [123I]-FP-CIT SPECT and a standardized oral levodopa test on 2 separate days in a randomized order within 3 weeks. The main outcome variables were the specific-to-nonspecific tracer uptake ratio in the contralateral putamen for SPECT analysis; latency, duration, and magnitude of the motor effect; and presence of dyskinesias for the levodopa test. The variable number of tandem repeat (VNTR) polymorphisms of the gene coding for DAT were detected for each patient by standard methods.
  
  
  RESULTS
  Contralateral putamen [123I]-FP-CIT uptake ratios were similar in the patients carrying the 9-copy allele (n=20) of the DAT VNTR compared with 10-repeat homozygotes (n=16). No significant difference was found in levodopa main outcome variables and dyskinesia incidence between the two groups of patients stratified by DAT VNTR polymorphism.
  
  
  CONCLUSIONS
  The study did not identify clinically relevant in vivo DAT neurochemical function phenotypes or levodopa response patterns associated with the DAT polymorphism.
authors.affiliation: Neurology Clinic, Department of Neurological Sciences, University of Bologna, Italy. contin@neuro.unibo.it
authors.forename: Manuela
authors.initials: M
authors.lastname: Contin
authors.forename: Paolo
authors.initials: P
authors.lastname: Martinelli
authors.forename: Mirella
authors.initials: M
authors.lastname: Mochi
authors.forename: Fiorenzo
authors.initials: F
authors.lastname: Albani
authors.forename: Roberto
authors.initials: R
authors.lastname: Riva
authors.forename: Cesa
authors.initials: C
authors.lastname: Scaglione
authors.forename: Maurizio
authors.initials: M
authors.lastname: Dondi
authors.forename: Stefano
authors.initials: S
authors.lastname: Fanti
authors.forename: Cinzia
authors.initials: C
authors.lastname: Pettinato
authors.forename: Agostino
authors.initials: A
authors.lastname: Baruzzi
mesh_terms: D000368:Aged; D000978:Antiparkinson Agents / Q000627:therapeutic use*; D050483:Dopamine Plasma Membrane Transport Proteins; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D007457:Iodine Radioisotopes; D007980:Levodopa / Q000627:therapeutic use*; D008297:Male; D008562:Membrane Glycoproteins / Q000235:genetics*; D026901:Membrane Transport Proteins / Q000235:genetics*; D008875:Middle Aged; D009043:Motor Activity / Q000187:drug effects; D009419:Nerve Tissue Proteins / Q000235:genetics*; D010300:Parkinson Disease / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000235:genetics; D011110:Polymorphism, Genetic; D011699:Putamen / Q000000981:diagnostic imaging; D011930:Reaction Time / Q000187:drug effects; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods; D014326:Tropanes
chemical_list: D000978:Antiparkinson Agents; D050483:Dopamine Plasma Membrane Transport Proteins; D007457:Iodine Radioisotopes; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; C493214:SLC6A3 protein, human; D014326:Tropanes; C087552:2-carbomethoxy-8-(3-fluoropropyl)-3-(4-iodophenyl)tropane; D007980:Levodopa