Normal dopamine transporter binding in dopa responsive dystonia

Abstract

We report the clinical manifestations of dopa responsive dystonia (DRD) in 2 patients from the same family. The brain magnetic resonance images (MRI) were normal. The dopamine transporter (DAT) imaging with (99m)Tc-TRODAT-1 was performed in the 2 probands, 8 patients with young onset Parkinson disease (YOPD) and 16 normal controls. The ratios of (99m)Tc-TRODAT-1 brain SPECT in the striatum were 2.40 +/- 0.12 (right) and 2.30 +/- 0.17 (left) in these 2 DRD patients as compared with 1.38 +/- 0.18 (right), 1.41 +/- 0.20 (left) in YOPD patients, and 2.15 +/- 0.35 (right), 2.14 +/- 0.32 (left) in normal controls respectively. A normal DAT uptake was found in DRD suggesting a normal presynaptic nigrostriatal dopaminergic terminal. We conclude that a normal DAT in parkinsonian patients can differentiate DRD from YOPD. In addition, DAT with (99m)Tc-TRODAT-1 is a reliable and convenient tool to study the function of the presynaptic dopaminergic axonal terminals.

Clinical and [^99mTc]TRODAT-1/[¹²³I]IBZM SPECT Imaging Findings in Dopa-Responsive Dystonia

“…Our findings and previous reports have all shown that DRD can be clearly differentiated from EOIP by using an [ 18 F]dopa PET [7, 8, 9]or DAT SPECT scan [3, 4, 5, 6]. Striatal binding of [ 18 F]dopa by using PET is normal or only mildly reduced, and that of DAT ligands labeled with [ 123 I] or [ 99m Tc] by using SPECT are normal in DRD but reduced in EOIP; however, the expense and limited availability of PET preclude its widespread clinical application.…”

“…Both dopamine transporter (DAT) single-photon emission computed tomography (SPECT) using [ 123 I]-based or [ 99m Tc]-based ligands and [ 18 F]dopa positron emission tomography (PET) have shown normal or only mildly reduced striatal uptake in DRD and clearly differentiate DRD from EOIP [3, 4, 5, 6, 7, 8, 9]. Dopamine D2 receptor densities are reported to be normal or elevated in DRD patients [10, 11], while [ 123 I]IBZM SPECT or [ 11 C]raclopride PET have shown initial upregulation of striatal dopamine D2 receptors in the contralateral putamen of early-stage idiopathic parkinsonism [12, 13], and normal [12]or reduced [14, 15, 16]D2 receptor densities in fluctuating idiopathic parkinsonism.…”

High frequency of multiexonic deletion of the GCH1 gene in a Taiwanese cohort of dopa‐response dystonia

“…99m Tc]TRODAT scan was normal in one patient reported previously [Huang et al, 2002]. The intact dopamine neuron might explain the extremely benign parkinsonian symptoms which were mild and progressed very slowly (20 and 14 years of duration in two patients).…”

“…There are limited reports about clinical phenotypes and genotypes of DRD among those with Chinese ethnicity from Taiwan and China [Huang et al, 2002;Wu et al, 2008]. The search for large exonic deletions was not mentioned in a recent report [Wu et al, 2008].…”

Diffuse White Matter Lesions in Carbon Disulfide Intoxication: Microangiopathy or Demyelination

“…Brain 99m Tc-TRODAT-1 SPECT was performed as previously described [15, 16, 17]. The brain 99m Tc-TRODAT-1 SPECT study showed normal DAT functioning at the dopaminergic pathway in the brain parenchyma.…”