Autonomic dysfunction in Machado-Joseph disease assessed by iodine123-labeled metaiodobenzylguanidine myocardial scintigraphy.

Iodine123-labeled metaiodobenzylguanidine, a radioiodinated analogue of norepinephrine, is a tracer for evaluating sympathetic function. We used iodine123-labeled metaiodobenzylguanidine myocardial scintigraphy and sympathetic skin response to study autonomic nervous functions in 19 patients with Machado-Joseph disease (MJD) and 20 control subjects. Planar imaging of all the participants was done to evaluate myocardial scintigraphy. The ratio of average counts in the heart to average counts in the mediastinum was calculated for both early and delayed images, the latter of which reflects the cardiac neural uptake of the tracer. Single photon emission computed tomography also was done on 12 patients with MJD to examine regional tracer uptake to the heart. The mean ratio of counts in the heart to counts in the mediastinum in the delayed images was lower for the patients with MJD than for the control subjects (p <0.01). Abnormal sympathetic skin response was present in 6 patients with MJD whose mean ratio of counts in the heart to counts in the mediastinum was lower than that of patients with MJD who had normal sympathetic skin response (p <0.01). A single photon emission computed tomography study showed significantly lower accumulation of the tracer in patients with MJD than in the control subjects in the anterior lateral sectors predominantly innervated by sympathetic nerves but not in the inferior septal sectors reported to be under main innervation by parasympathetic fibers. These results show that MJD is accompanied by cardiac sympathetic dysfunction, as detected by iodine123-labeled metaiodobenzylguanidine myocardial scintigraphy, which appears to be correlated with sudomotor sympathetic dysfunction.

A single nucleotide polymorphism of dopamine transporter gene is associated with Parkinson's disease.

We identified two polymorphisms out of all coding regions of the dopamine transporter gene. One existed in exon 9 (1215A/G) and another in exon 15 (1898T/C). The 1215G was significantly less frequent among patients with Parkinson's disease than the controls. Although the polymorphism caused no amino acid substitution, we concluded that it was associated with decreasing the susceptibility to Parkinson's disease through mechanisms other than the protein function of dopamine transporter.

[Iodine-123-labeled meta-iodobenzylguanidine myocardial scintigraphy evaluation of Machado-Joseph disease].

Iodine-123-labeled meta-iodobenzylguanidine ([123I]MIBG), an analogue of guanetidine, is used as a tracer for evaluation of the function of sympathetic neurons. To investigate cardiac sympathetic function in Machado-Joseph disease (MJD), [123I] MIBG myocardial scintigraphy was performed in 12 patients with MJD and 20 controls. In planar imaging studies, the heart to the mediastinum of the average count ratio (H/M) was calculated for both early and delayed images. The mean values of H/M in delayed images of MJD was lower than those of controls (p < 0.01), but this did not correlate with duration of the illness. The mean values of H/M in MJD patients with abnormal sympathetic skin response (SSR) was lower than that with normal SSR (p < 0.05). The decrease of H/M in delayed image is more sensitive than abnormal SSR. The increase of heart rate after standing in the patients with low H/M was lower than those with normal H/M. Abnormal cardiac sympathetic function revealed by [123I]MIBG myocardial scintigraphy in MJD can be seen earlier than abnormal sudomotor system detected by SSR.

Characteristic magnetic resonance imaging findings in Machado-Joseph disease.

OBJECTIVE: To clarify the characteristic magnetic resonance imaging (MRI) findings in patients with Machado-Joseph disease (MJD) diagnosed by genetic analysis. PATIENTS AND METHODS: Using MRI, we examined 31 patients genetically diagnosed as having MJD, 20 patients with sporadic olivopontocerebellar atrophy, and 26 control subjects. RESULTS: The MRIs of patients with MJD disclosed remarkably reduced width of the superior cerebellar peduncles, atrophy in the frontal and temporal lobes, diminished transverse diameter of the globus pallidus, and decreased anteroposterior and transverse diameters of the pons, which correlated with the width of the middle cerebellar peduncle. The width of the superior cerebellar peduncles also correlated with the diameter of the dentate or red nucleus in patients with MJD, but not in controls or in patients with sporadic olivopontocerebellar atrophy. On T2- and/or proton-weighted axial MR imaging, a high signal intensity in the transverse pontine fibers was observed in 14 (45.2%) of 31 patients with MJD and in all patients with sporadic olivopontocerebellar atrophy, but not in any controls. CONCLUSION: Affected afferent and efferent cerebellar tracts and atrophy of the frontal and temporal lobes and globus pallidus are characteristics of MRI of patients with MJD.