Dopa-responsive dystonia: [18F]dopa positron emission tomography.
The syndrome of dopa-responsive dystonia comprises a minority of patients with dystonia, yet it is of considerable diagnostic importance because patients respond dramatically to L-dopa therapy. Benefits from this treatment are lasting, and the problems associated with long-term L-dopa therapy in patients with Parkinson's disease are generally absent. It has been suggested that this condition is due to a defect in the dopamine synthetic pathway, which is bypassed when patients are treated with L-dopa. We have studied [18F]dopa uptake in 6 patients with classic dopa-responsive dystonia (5 familial patients and 1 sporadic patient), aged 18 to 66 years. Data have been analyzed according to a graphic approach, calculating an influx constant for each region studied. We have also studied a seventh, clinically atypical, patient with juvenile dystonia-parkinsonism. Similar data have been calculated for a group of 10 healthy control subjects and 10 patients with Parkinson's disease. The 6 patients with typical dopa-responsive dystonia had a modest but significant reduction in the uptake of tracer into both caudate and putamen, which indicates a defect in the decarboxylation, vesicular uptake, and storage of [18F]dopa. This argues against the proposition that dopa-responsive dystonia is due to an inherited defect of tyrosine hydroxylase alone. In the atypical patient, however, we found a greater reduction of [18F]dopa uptake into both caudate and putamen, comparable with that in patients with Parkinson's disease.
Sawle
G V
GV
MRC Cyclotron Unit, Hammersmith Hospital, Villigen, Switzerland.
Leenders
K L
KL
Brooks
D J
DJ
Harwood
G
G
Lees
A J
AJ
Frackowiak
R S
RS
Marsden
C D
CD
D000293:Adolescent; D000328:Adult; D000368:Aged; D001692:Biological Transport; D002421:Caudate Nucleus / Q000000981:diagnostic imaging / Q000378:metabolism*; D003653:Decarboxylation; D004295:Dihydroxyphenylalanine / Q000493:pharmacokinetics / Q000627:therapeutic use*; D004298:Dopamine / Q000096:biosynthesis; D004421:Dystonia / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism; D005260:Female; D005462:Fluorine Radioisotopes; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000378:metabolism; D011699:Putamen / Q000000981:diagnostic imaging / Q000378:metabolism*; D014018:Tissue Distribution; D014055:Tomography, Emission-Computed; D014446:Tyrosine 3-Monooxygenase / Q000172:deficiency / Q000378:metabolism
D005462:Fluorine Radioisotopes; D004295:Dihydroxyphenylalanine; D014446:Tyrosine 3-Monooxygenase; D004298:Dopamine