Clinical characteristics of patients with Parkinson's disease with reduced 123I-metaiodobenzylguanidine uptake in the major salivary glands and heart

BACKGROUND

Parkinson's disease (PD) shows cardiac sympathetic denervation (SD) in 123I-metaiodobezylguanidine (MIBG) scintigraphy. Recently, SD in the major salivary glands (MSG-SD) was introduced as a possible radiological feature of PD.

OBJECTIVE

To identify the clinical characteristics of patients with PD with reduced MSG and cardiac MIBG uptake (dual-SD) compared with those with reduced MSG or cardiac MIBG uptake only (single-SD).

METHODS

We recruited 90 patients with PD and 30 controls and evaluated their non-motor (e.g., hyposmia, autonomic dysfunction) and motor (e.g., Movement Disorder Society-Unified Parkinson's Disease Rating Scale) features. We also assessed MIBG uptake in the MSG and heart using a quantitative semi-automatic method, and compared MIBG uptakes between PD and controls. We set cut-off values for optimal sensitivity and specificity, and compared the clinical characteristics of patients with PD between dual- and single-SD groups.

RESULTS

MSG and cardiac MIBG uptakes were significantly reduced in PD. Sixty-one patients had dual-SD, 25 had single-SD, and four had non-SD. In patients with PD with normal cardiac SD, 76.5% (13/17) of whom showed abnormalities only in MSG-SD. When clinical characteristics were compared between the dual-SD and single-/non-SD groups, patients in the dual-SD group were older and had more severe hyposmia and autonomic dysfunction, except motor features. Multiple logistic regression analysis identified age as an important confounder.

CONCLUSIONS

Patients with PD with dual-SD have more severe non-motor features than other patients. Autonomic dysfunction might progress independently from dopaminergic degeneration. Furthermore, our findings indicate that aging is a crucial factor in PD progression.

Dravet syndrome with parkinsonian symptoms and intact dopaminergic neurons: A case report

INTRODUCTION

Dravet syndrome (DS) is severe myoclonic epilepsy in infancy and associated with a heterozygous mutation of the gene for the sodium channel alpha 1 subunit (SCN1A). Recently, adult patients with DS have been reported to show parkinsonism, but no corresponding neuroimaging data are available. Here, we present neuroimaging data in 2 adult patients with DS showing parkinsonian symptoms.

CASE REPORT

Case 1: A man who had intractable seizures from the age of 1 year and 2 months was diagnosed with DS at 7 with a mutation in the SCN1A gene. At 18, he had parkinsonian symptoms such as masked face and bradykinesia. At 20, he was admitted to our department. Dopamine transporter single-photon emission computed tomography (DAT SPECT) showed no decrease in striatal binding of ¹²³I-N-ω-fluoropropyl-2β-carbomethoxy-3β-(4-iodophenyl) nortropane (¹²³I-FP-CIT), and myocardial scintigraphy showed no decrease in cardiac uptake of ¹²³I-metaiodobenzylguanidine (¹²³I-MIBG). Levodopa showed no significant improvement in his symptoms. Case 2: A woman who had febrile seizures at 4 months of age and myoclonic seizures at 1 year and 5 months was diagnosed with DS at 31. She had myoclonus, resting tremor, hypertonia, antecollis, crouch gait, and bradykinesia. DAT SPECT imaging showed no decrease in striatal FP-CIT binding, and levodopa did not improve her symptoms.

DISCUSSION

The normal DAT SPECT and ¹²³I-MIBG results suggest that dopaminergic neurons projecting onto striatal neurons were not impaired in our patients, explaining the lack of response to levodopa. Thus, dopamine imaging can help to guide treatment decisions in patients with DS and parkinsonism.

PLA2G6 variants associated with the number of affected alleles in Parkinson's disease in Japan

This study aimed to evaluate genotype-phenotype correlations of Parkinson's disease (PD) patients with phospholipase A2 group V (PLA2G6) variants. We analyzed the DNA of 798 patients with PD, including 78 PD patients reported previously, and 336 in-house controls. We screened the exons and exon-intron boundaries of PLA2G6 using the Ion Torrent system and Sanger method. We identified 21 patients with 18 rare variants, such that 1, 9, and 11 patients were homozygous, heterozygous, and compound heterozygous, respectively, with respect to PLA2G6 variants. The allele frequency was approximately equal between patients with familial PD and those with sporadic PD. The PLA2G6 variants detected frequently were identified in the early-onset sporadic PD group. Patients who were homozygous for a variant showed more severe symptoms than those who were heterozygous for the variant. The most common variant was p.R635Q in our cohort, which was considered a risk variant for PD. Thus, the variants of PLA2G6 may play a role in familial PD and early-onset sporadic PD.

Young-Onset Dementia with Lewy Bodies

Young-onset (< 65 years) dementia is a challenging clinical problem. A 61-year-old man visited our clinic because of a 2-year history of mild cognitive impairment of the executive disorder type. He was initially suspected of having young-onset Alzheimer's disease due to the lack of motor signs or hippocampal atrophy by conventional brain MRI. However, he proved to have anosmia, erectile dysfunction, hypersexuality, constipation, REM sleep behavior disorder, and emotional lability; imaging findings included positive brain perfusion SPECT, nigrosome MRI, DAT scan, and MIBG myocardial scintigraphy. All these clinical imaging features led to the correct diagnosis of young-onset dementia with Lewy bodies (YOD-DLB). It is hoped that this case report will help facilitate a future prospective study to diagnose and follow YOD-DLB patients with the aim of determining appropriate management and care.

Role of (123)I-Iobenguane Myocardial Scintigraphy in Predicting Short-term Left Ventricular Functional Recovery: An Interesting Image

(123)I-iobenguane myocardial scintigraphy (MIBG) has been shown to be a predictor of sudden cardiac mortality in patients with heart failure. One patient with recent anterior myocardial infarction (MI) treated with coronary angioplasty and having left ventricular ejection fraction (LVEF) of 30% underwent early MIBG myocardial scintigraphy/tetrofosmin single-photon emission computed tomography (SPECT) in order to help evaluate his eligibility for implantable cardioverter defibrillator (ICD). The late heart/mediastinum (H/M) ratio was calculated to be 1.32% and the washout rate was 1%. At 40-day follow-up after angioplasty, LVEF proved to be 32%, New York Heart Association (NYHA) class was still II-III, and an ICD was placed in order to reduce mortality from ventricular arrhythmias. MIBG myocardial scintigraphy might be a promising method for evaluating left ventricular recovery in post-MI patients.

Utility of the combination of DAT SPECT and MIBG myocardial scintigraphy in differentiating dementia with Lewy bodies from Alzheimer's disease

Purpose

¹²³I-2β-Carbomethoxy-3β-(4-iodophenyl)-N-(3-fluoropropyl) nortropane (¹²³I-FP-CIT) dopamine transporter single photon emission computed tomography (DAT SPECT) and ¹²³I-metaiodobenzylguanidine (MIBG) myocardial scintigraphy can be used to assist in the diagnosis of patients with dementia with Lewy bodies (DLB). We compared the diagnostic value of these two methods in differentiating DLB from Alzheimer’s disease (AD). Furthermore, we evaluated whether a combination of DAT SPECT and MIBG myocardial scintigraphy would provide a more useful means of differentiating between DLB and AD.

Methods

Patients with AD (n = 57) and patients with DLB (n = 76) who underwent both DAT SPECT and MIBG myocardial scintigraphy were enrolled. The sensitivity, specificity, and accuracy of both methods as well as their combination for differentiating DLB from AD were calculated. Moreover, we examined whether symptoms of the patients with DLB were associated with the patterns of the abnormalities displayed on DAT SPECT and MIBG myocardial scintigraphy.

Results

The sensitivity and specificity of differentiating DLB from AD were 72.4 and 94.4 % by the heart to mediastinum ratio of MIBG uptake, 88.2 and 88.9 % by the specific binding ratio on DAT SPECT, and 96.1 and 90.7 % by their combination, respectively. The combined use of DAT SPECT and MIBG myocardial scintigraphy enabled more accurate differentiation between DLB and AD compared with either DAT SPECT or MIBG myocardial scintigraphy alone. There was a significantly higher frequency of parkinsonism in the abnormal DAT SPECT group than the normal DAT SPECT group. On the other hand, there was a higher frequency of the appearance of rapid eye movement (REM) sleep behavior disorder in the abnormal MIBG uptake group than the normal MIBG uptake group.

Conclusion

These results suggested that using a combination of these scintigraphic methods is a useful and practical approach to differentiate DLB from AD.