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Alpha-synuclein plays a key role in the pathology of synucleinopathies including Parkinson's disease (PD) and multiple system atrophy (MSA). However, whether alpha-synuclein level in cerebrospinal fluid (CSF) could distinguish synucleinopathies from progressive supranuclear palsy (PSP) is still a contentious issue. A comprehensive literature search yielded nine eligible studies. We expressed the between-group difference of the concentration of alpha-synuclein in CSF as the standardized mean difference. The proportion of variation attributable to heterogeneity was computed and expressed as I2. Nine studies involved 537 controls, 843 PD, 130 MSA, and 98 PSP patients. The overall effect of PD on alpha-synuclein in CSF was significantly different from normal control or disease control (standardized mean difference = -0.67, P < 0.00001). These studies were heterogeneous (I2 = 40%). Alpha-synuclein in CSF in MSA was significantly reduced relative to controls with heterogeneous studies (standardized mean difference = -0.75, P < 0.0001; I2 = 62%). In contrast, no significant difference of alpha-synuclein in CSF was observed between PSP and controls with heterogeneous studies (standardized mean difference = -0.28, P = 0.13; I2 = 53%). Alpha-synuclein in CSF was significantly reduced in synucleinopathies compared with PSP ('PD vs. PSP': standardized mean difference = -0.38, P = 0.001; 'MSA vs. PSP': standardized mean difference = -0.66, P < 0.00001). The included studies were homogeneous (I2 = 0%). Our study showed that alpha-synuclein levels in CSF in synucleinopathies was significantly lower than in PSP. This finding provides insights into the pathophysiological difference between synucleinopathies and PSP as well as possibility of development of a tool for differential diagnosis between MSA and PSP using enzyme-linked immunosorbent assay (ELISA) and similar methods. © 2014 International Parkinson and Movement Disorder Society [ABSTRACT FROM AUTHOR]

Background: Parkinson's disease (PD) involves the degeneration of dopaminergic neurons in substantia nigra (SN) compacta. However, it is still a contentious issue whether magnetic resonance imaging (MRI) can detect the nigral volume loss in PD patients. Objective: We synthesized the results of published research on SN volumetry using a meta-analysis method in order to clarify this issue. Methods: A comprehensive literature search yielded 8 eligible studies. Nigral size was expressed as the standardized mean difference (SMD) between normal controls and PD patients. In addition, subgroup analysis was performed in order to identify the best condition for nigral volumetry. The proportion of variation due to heterogeneity was computed and expressed as I2. Results: Eight studies involved 172 normal control and 193 PD patients. The overall effect indicated that nigral volume in PD was significantly smaller than normal controls with homogeneous studies (SMD = -0.65, P < 0.0001; I2 = 47%). Maximum of subgroup effect was observed in 'volumetry' among three approaches ('thickness': SMD = -0.35, P = 0.18, I2 = not available; 'area': SMD = -0.39, P = 0.14, I2 = 0%; 'volumetry': SMD = -0.82, P = 0.0006, I2 = 56%). The approach including T1-weighted images (T1WI) showed larger effect ('with T1WI': SMD = -1.11, P < 0.00001, I2 = 36%; 'without T1WI': SMD = -0.32, P = 0.04, I2 = 0%). Conclusions: These findings suggest that volumetry based on T1WI could be the most sensitive option to identify nigral volume loss in PD patients. [ABSTRACT FROM AUTHOR]

Amyotrophic lateral sclerosis (ALS) is a devastating progressive motor neuron disease that affects people of all ethnicities. Approximately 90% of ALS cases are sporadic and thought to have multifactorial pathogenesis. To understand the genetics of sporadic ALS, we conducted a genome-wide association study using 1,173 sporadic ALS cases and 8,925 controls in a Japanese population. A combined meta-analysis of our Japanese cohort with individuals of European ancestry revealed a significant association at the ACSL5 locus (top SNP p = 2.97 × 10−8). We validated the association with ACSL5 in a replication study with a Chinese population and an independent Japanese population (1941 ALS cases, 3821 controls; top SNP p = 1.82 × 10−4). In the combined meta-analysis, the intronic ACSL5 SNP rs3736947 showed the strongest association (p = 7.81 × 10−11). Using a gene-based analysis of the full multi-ethnic dataset, we uncovered additional genes significantly associated with ALS: ERGIC1, RAPGEF5, FNBP1, and ATXN3. These results advance our understanding of the genetic basis of sporadic ALS. Gen Sobue, Masao Nagasaki and colleagues report a genome-wide association study for amyotrophic lateral sclerosis (ALS) in a large, multi-ethnic cohort comprising Japanese, Chinese, and European ancestry populations. They find a significant association to variants within the ACSL5 gene and identify novel associations with 4 additional genes using a gene-based approach. [ABSTRACT FROM AUTHOR]

Previous studies have reported the usefulness of superior cerebellar peduncle (SCP) abnormalities in diagnosing progressive supranuclear palsy. However, the results of these studies were heterogeneous. In the present meta-analysis, we aimed to establish more robust evidence of SCP abnormalities in progressive supranuclear palsy, and to determine the cause of the previously reported heterogeneity. We identified six studies on SCP size and three studies on apparent diffusion coefficient. Key features of each study were extracted and standardized differences in size and apparent diffusion coefficient values were calculated. There was some heterogeneity in terms of the reduction in SCP size in patients with progressive supranuclear palsy compared to those with Parkinson's disease. Moreover, age and Hoehn-Yahr stage negatively correlated with standardized mean difference in SCP size between patients with progressive supranuclear palsy and Parkinson's disease. There was homogenous agreement that the SCP was smaller in patients with progressive supranuclear palsy compared to those with multiple system atrophy. Finally, in terms of apparent diffusion coefficient, there was no significant difference between patients with progressive supranuclear palsy, Parkinson's disease, or multiple system atrophy. Together, these findings suggest that SCP size, when corrected for age and disease severity, could be a diagnostic tool for progressive supranuclear palsy. [ABSTRACT FROM AUTHOR]

The measurement of middle cerebellar peduncle (MCP) width allows for differential diagnosis between Parkinson's disease (PD) and multiple system atrophy with predominant parkinsonian features (MSA-P). However, it remains controversial whether apparent diffusion coefficient (ADC) value in the MCP of MSA-P is elevated or not. In the present study, we aimed to assess the usefulness of ADC value in the MCP for differential diagnosis between PD and MSA-P. An on-line literature search yielded 5 eligible studies. We expressed between-group difference of ADC value as the standardized mean difference (SMD). The proportion of variation due to heterogeneity was computed and expressed as I 2 . ADC in the MCP of MSA-P was significantly increased compared with PD with heterogeneous studies ( P = 0.0007, I 2 = 81%). A meta-regression analysis of MSA-P was conducted for “UPDRS III”, and revealed a significant correlation between UPDRS III and SMD ( P = 0.01). Our meta-regression analysis has clarified the contribution of severity of MSA-P to heterogeneity of the included studies for ADC in the MCP. This finding raised the possibility that ADC in the MCP depended on severity of MSA-P, and less severe patients with MSA-P should be mainly enrolled in future study to assess the ability for differential diagnostic tool. [ABSTRACT FROM AUTHOR]

A reliable test that facilitates the accurate diagnosis of Parkinson's and disorders will help with both, clinical management and therapeutic research. In this context, neurofilament light chain (NFL) is candidate for a biomarker in cerebrospinal fluid (CSF). A comprehensive literature search yielded 4 eligible studies. We expressed between-group difference of NFL concentration in CSF as the standardized mean difference. Four studies involved 166 Parkinson's disease (PD), 116 multiple system atrophy (MSA) and 73 progressive supranuclear palsy (PSP) patients. Patients with MSA showed higher concentration of NFL concentration in CSF than those with PD (standardized mean difference = 1.60, P < 0.0001). These studies were homogeneous ( P = 0.17). NFL in CSF in PSP was significantly elevated relative to PD with homogeneous studies (standardized mean difference = 2.04, P < 0.0001; P = 0.99). The present meta-analysis suggested that NFL concentration in CSF in MSA and PSP was significantly increased relative to PD, and that this could help us to separate PD from atypical parkinsonian syndromes. [ABSTRACT FROM AUTHOR]

Abstract: UCHL1 plays an important role in the ubiquitin-proteasome system and is a biologically plausible candidate gene for Parkinson’s disease (PD). However, results from genetic association studies of the UCHL1 S18Y polymorphism have been equivocal. Meta-analyses indicate that the polymorphism’s risk effect might be restricted to Asian populations and early-onset disease. To further explore the role of UCHL1 in PD, we genotyped S18Y in 605 PD patients and 1620 controls of Japanese ancestry. We did not find evidence of an association in the overall sample (SY vs. SS: adjusted OR=1.11, P =0.37; YY vs. SS: adjusted OR=1.01, P =0.94). In the early-onset stratum, however, we observed a trend toward a reduction in risk for those with the Y allele (SY vs. SS, adjusted OR, 0.75; 95% CI, 0.47–1.20; YY vs. SS, OR, 0.64; 95% CI, 0.36–1.14; trend test, P =0.12). These results indicate that, if involved in PD, the S18Y variant is not a major determinant of risk and its effect might be restricted to early-onset disease. [Copyright &y& Elsevier]