Probable Multiple System Atrophy Research Articles

Clinically Probable Multiple System Atrophy Presenting Ptosis as an Early Manifestation

Many ocular features were found in patients with multiple system atrophy (MSA), which include dry eye, blepharospasm, eye movement problems, and blink reflex dysfunction. Some of these symptoms are associated with autonomic dysfunctions seen in MSA. We report a young clinically-probable MSA patient with bilateral ptosis at an early disease stage. Although there is no clear evidence that ptosis, in this case, was caused by abnormalities in the sympathetic cholinergic system, the selective impairment of sudomotor function implied an injured sympathetic cholinergic system secondary to MSA pathology. Ocular manifestations need more attention in clinical examinations of patients with MSA.

Sleep disturbances in probable multiple system atrophy

BackgroundMultiple system atrophy (MSA) is a fatal alpha-synucleinopathy characterized by variable combinations of parkinsonism, autonomic and cerebellar dysfunction. Sleep in MSA is highly compromised due to various sleep disturbances. Disrupted sleep-wake cycles in MSA contribute to poor health-related quality of life and are negative prognostic factors. ObjectivesWe aimed to study the various sleep disturbances; the effect of parkinsonian and cerebellar phenotypes on sleep; and the correlation of sleep parameters with disease severity in an Asian-Indian cohort of probable MSA patients. MethodsWe recruited 60 probable MSA patients (MSA-P = 19; MSA-C = 41). Disease severity was assessed using UPDRS-III, UMSARS-I and UMSARS-II. Detailed history and relevant sleep questionnaires were applied to evaluate the sleep disturbances. ResultsSleep disturbances were universally observed in probable MSA patients in this cohort. These include REM behavior disorder (RBD)-95 %; poor sleep quality-80 %; secondary insomnia and intermittent awakenings-100 %; excessive daytime sleepiness-26 %; risk for obstructive sleep apnea-51.7 % and snoring-85 %. MSA patients reported 38.2 ± 22.9 percentage improvement in sleep with the medications. There was no significant difference between probable MSA-P and MSA-C patients in any of the sleep parameters. Sleep quality was poor in patients with pre-motor RBD than post-motor RBD (p < 0.01). Poor sleep quality had a moderate positive correlation with RBD duration. Disease severity positively correlated with RBD duration and poor sleep quality. ConclusionsSleep disturbances, the negative prognostic factors, were universally observed in this Asian Indian MSA cohort. This study provides supporting evidence that RBD might play a possible role in MSA disease severity, progression, and sleep quality.

Imaging Markers of Multiple System Atrophy and Their Association With Disease Severity: A Cross-Sectional Study.

Background Multiple system atrophy (MSA) is a rare, adult-onset neurodegenerative disorder marked by autonomic failure, parkinsonism, and cerebellar ataxia, with subtypes classified as parkinsonian (MSA-P), cerebellar (MSA-C), and autonomic (MSA-A). This study aims to identify MRI biomarkers for MSA and their correlation with disease severity. Methodology A total of 30 patients with probable MSA (20 MSA-C, 10 MSA-P) aged 45-65 years were studied. Motor and non-motor symptoms were assessed using the Unified Multiple System Atrophy Rating Scale (UMSARS), and all patients underwent 3T MRI brain imaging. Data analysis was performed using SPSS version 22 (IBM Corp., Armonk, NY, USA) with Spearman's correlation for clinical-imaging correlations. Results The mean age of the study population was 54.43 years, with a male predominance (56.7%). The most common symptoms included gait ataxia (43.3%) and urinary dysfunction (96.7%), with orthostatic symptoms in 33.3%. Moderate disease severity was observed, with mean UMSARS scores of 15.9 (Part 1) and 16 (Part 2), showing no significant subtype differences. MRI revealed abnormalities in all patients, predominantly cerebellar atrophy (90%). The "hot cross bun" (HCB) sign was seen in 75% of MSA-C patients, but none of MSA-P patients showed the same. The HCB sign was significantly correlated with severity in MSA-C (USMSARS-4). Putaminal signs were less frequent and slightly more prevalent in MSA-P, without significant clinical-imaging correlation. Conclusions This study reinforces the critical role of MRI biomarkers in the diagnosis of MSA patients. Notably, the HCB sign exhibited a significant association with clinical severity in MSA-C patients, while such correlation was absent in MSA-P cases.

Prevalence and impact of sleep-related breathing disorder in multiple system atrophy patients: a cross-sectional study and meta-analysis.

Sleep-related breathing disorder (SRBD) is a prevalent non-motor symptom in multiple system atrophy (MSA). However, the reported prevalence of SRBD in MSA from different studies has shown inconsistency. Additionally, only one study has examined the impact of SRBD on both motor and non-motor symptoms in MSA. Cross-sectional study of 66 patients with probable MSA from China. SRBD was ascertained with polysomnography (PSG). All the MSA individuals were assessed using the Epworth Sleepiness Scale (ESS), Unified Multiple-System Atrophy Rating Scale (UMSARS), Hamilton Depression Scale (HAMD), Hamilton Anxiety Scale (HAMA), the Mini-mental State Examination (MMSE), Non-Motor Symptoms Scale (NMSS), and Pittsburgh Sleep Quality Index (PSQI). Moreover, a meta-analysis was conducted by searching studies related to MSA and SRBD in PubMed, Web of Science, Embase, and Cochrane databases. Data were pooled as necessary to calculate prevalence of SBRD with 95% confidence intervals (CI). Our study included 66 patients with MSA, 52 of whom had a diagnosis of SRBD (78.8%). There were no significant differences between the MSA with SRBD and without SRBD groups on the age, sex, disease onset, disease duration, UMSARS I, II, and IV, the NMSS, the HAMA, HAMD, the ESS the FSS, the MMSE, and the PSQI scales. However, MSA patients with SRBD having a significant higher obstructive apnea index and percentage of snoring during sleep than MSA patients without SRBD [10.0 (4.1-10.6) vs. 0.1 (0-0.3), and 8.3 (5.1-12.2) vs. 4.2 (0-7.5)]. Also, between the two groups, the mean and minimum oxygen concentrations during sleep were lower in MSA patients with SRBD than in those without SRBD [93.7 (93-95) vs. 95.5 (95.8-97), p = 0.001] and [83.9 (81.2-89.0) vs. 90.3 (89.8-93.3), p = 0.000]. The primary search strategy identified 701 articles, with 10 meeting the inclusion criteria. The overall prevalence of SRBD in a combined sample of 295 MSA patients was found to be 60.5% (95% CI, 43.2-76.5%). Further analysis revealed that the prevalence of SRBD in MSA patients in Asia was 79.2% (95% CI, 54.7-96.3%), which was higher than that in Europe (41.6, 95% CI, 32-51.5%). The study found a prevalence of 78.8% of SRBD in MSA patients, with a notably higher prevalence in Asia compared to Europe. The majority of SRBD cases in MSA were attributed to obstructive apnea. Furthermore, the presence of SRBD did not show a significant impact on the motor and non-motor symptoms of MSA patients.

Early-onset dysphagia predicts short survival in multiple system atrophy.

The prognostic impact of dysphagia in multiple system atrophy (MSA) remains controversial. This study aimed to investigate the relationship between dysphagia severity and survival in MSA and to elucidate whether this impact differs between MSA-cerebellar ataxia (MSA-C) and MSA-parkinsonism (MSA-P). This retrospective study included 297 patients with MSA: 251 met criteria for clinically established MSA and 46 for clinically probable MSA. Among them, 171 had MSA-C and 126 had MSA-P. We evaluated symptomatic dysphagia within 3years of onset and quantified dysphagia severity using the Hyodo score (0 to 12) through fibreoptic endoscopic evaluation of swallowing (FEES) and clinical features, including autonomic dysfunction and vocal cord paralysis. Patients were followed up until death or tracheostomy, and survival factors were analysed using the log-rank test and multivariate Cox proportional hazards model. Ninety patients developed symptomatic dysphagia within 3years of onset, and 75 were evaluated for dysphagia severity using FEES. Survival from onset was shorter in patients with dysphagia within 3years compared to those without (median: 4.2years vs. 7.3years; p < 0.001). Symptomatic dysphagia within 3years of onset was an independent predictor of shorter survival in the multivariate Cox analysis. While the Hyodo score was higher in MSA-P than in MSA-C patients (p = 0.048), the Hyodo score was associated with survival in both MSA-C and MSA-P patients (log-rank p < 0.001 and p = 0.046, respectively). Symptomatic dysphagia within 3years of onset predicts shorter survival in MSA-C and MSA-P patients.

An update on multiple system atrophy.

Multiple system atrophy (MSA) is a rapidly progressive synucleinopathy characterized by autonomic failure, parkinsonism, and cerebellar ataxia. Here, we provide an update on α-synuclein's role in MSA pathophysiology and review the new Movement Disorders Society (MDS) diagnostic criteria and the utility of α-synuclein-based biomarkers. We also highlight ongoing efforts toward clinical trial readiness and review potential disease-modifying therapies undergoing clinical trials. A role of urinary tract infections in triggering α-synuclein aggregation and contribution of genes implicated in oligodendroglial development have been suggested in the MSA pathophysiology. The clinically probable MSA category of the new diagnostic criteria shows improved accuracy in early disease stages. Predictors of phenoconversion from pure autonomic failure to MSA are now better defined. Alpha-synuclein strains in CSF and serum, phosphorylated α-synuclein deposits in the skin, and brain α-synuclein pathology visualized using PET ligand [18F]ACI-12589 are emerging as valuable diagnostic tools. Clinical trials in MSA investigate drugs targeting α-synuclein aggregation or preventing α-synuclein expression, along with stem cell and gene therapies to halt disease progression. New MSA diagnostic criteria and α-synuclein-based biomarkers may enhance diagnostic accuracy while promising therapies are in development to address disease progression.

Severity of sleep apnea as a prognostic factor for mortality in patients with multiple system atrophy

BackgroundWe determined whether the severity of sleep apnea increases the risk of mortality in patients with multiple system atrophy (MSA) with and without stridor.MethodsThis retrospective study included patients who underwent polysomnography within one year after diagnosis of probable MSA. Stridor, sleep apnea, and arousal from sleep were determined using full-night polysomnography. Disease severity was measured using the Unified MSA Rating Scale (UMSARS). Survival data were collected and analyzed using Cox regression analysis. ResultsSixty-four patients with MSA were included. During a median follow-up of 34.5 months, 49 (76.6 %) patients died. Stridor was present in 56.3 % of patients. Patients with stridor had more severe sleep apnea and shorter sleep time than those without, but the hazard ratio (HR) for death did not differ between patients with and without stridor. Among patients without stridor, apnea-hypopnea index ≥30/h (HR, 6.850; 95 % confidence interval [CI], 1.983–23.664; p = 0.002) and a score of UMSARS I + II (HR, 1.080; 95 % CI, 1.040–1.121; p < 0.001) were independently associated with death. In contrast, among patients with stridor, frequent arousals from sleep (HR, 0.254; 95 % CI, 0.089–0.729; p = 0.011) were a significant factor associated with longer survival, while MSA-cerebellar type tended to be associated with poor survival (HR, 2.195; 95 % CI, 0.941–5.120; p = 0.069). ConclusionThe severity of sleep apnea might be a significant predictor of shorter survival in MSA patients without stridor, whereas frequent arousals from sleep might be a significant predictor for longer survival in MSA patients with stridor.

Clinical and Autonomic Features Suggest Phenoconversion from Sporadic Adult-onset Ataxia to Clinically Probable Multiple System Atrophy (P6-3.019)

Clinical and Autonomic Features Suggest Phenoconversion from Sporadic Adult-onset Ataxia to Clinically Probable Multiple System Atrophy (P6-3.019)

Monash-Alfred protocol for assessment of atypical parkinsonian syndromes (MAP-APS)

IntroductionAtypical parkinsonian syndromes (APS) are rare neurodegenerative syndromes for which parkinsonism is one significant feature. APS includes progressive supranuclear palsy (PSP), multiple system atrophy (MSA) and corticobasal syndrome (CBS). The...

Two patients of immunotherapy-responsive autoimmune cerebellar ataxia fulfilled with criteria of multiple system atrophy

We report two patients with autoimmune cerebellar ataxia who fulfilled the diagnostic criteria of multiple system atrophy (MSA) and responded to immunotherapies. Patient 1 was a 72-year-old man who was diagnosed with clinically probable MSA according to Movement Disorder Society criteria. Patient 2 was a 68-year-old man who was diagnosed with clinically established MSA according to Movement Disorder Society criteria. Both patients showed cerebellar ataxia, autonomic dysfunction, and pyramidal tract signs; however, they also had atypical clinical features. Patient 1 exhibited self-‍limiting mild improvement of clinical symptoms and had inflammatory findings in his cerebrospinal fluid. Patient 2 showed a rapidly progressive clinical course. We therefore examined anti-neuronal antibodies using tissue-based immunohistochemical assays with frozen rat cerebellum sections. We detected autoantibodies that mainly reacted with the cytoplasm of Purkinje cells. The two patients then underwent immunotherapies, which led to substantial improvements in their clinical symptoms. Our findings indicate that some patients with autoimmune cerebella ataxia have clinical features that resemble MSA, and respond well to immunotherapies.

Validation Study of the MDS Criteria for the Diagnosis of Multiple System Atrophy in the Mayo Clinic Brain Bank.

The second consensus criteria in 2008 have been used in diagnosing multiple system atrophy (MSA). The International Parkinson and Movement Disorder Society (MDS) proposed new diagnostic criteria for MSA in 2022. This study aimed to compare the diagnostic accuracy between these 2 criteria and validate the clinical utility of the newly proposed criteria for MSA. We conducted a retrospective autopsy cohort study of consecutive patients with a clinical or pathologic diagnosis of MSA from the Mayo Clinic brain bank between 1998 and 2021. We studied 352 patients (250 pathologically diagnosed MSA and 102 non-MSA); MDS criteria and the second consensus criteria were applied. The sensitivity, specificity, and area under the curve (AUC) of receiver operating characteristic curves were compared between these criteria. Comparison was conducted between clinical subtypes and among clinically challenging cases (those with different clinical diagnoses or those with suspected but undiagnosed MSA before death). We also used machine learning algorithm, eXtreme Gradient Boosting, to identify clinical features contributing diagnostic performance. The sensitivity and specificity of clinically established and probable MSA by the MDS criteria were 16% and 99% and 64% and 74%, respectively. The sensitivity and specificity of probable MSA and possible MSA by the second consensus criteria were 72% and 52% and 93% and 21%, respectively. The AUC of MDS clinically probable MSA was the highest (0.69). The diagnostic performance did not differ between clinical subtypes. In clinically challenging cases, MDS clinically established MSA maintained high specificity and MDS clinically probable MSA demonstrated the highest AUC (0.62). MRI findings contributed to high specificity. In addition, combining core clinical features with 2 or more from any of the 13 supporting features and the absence of exclusion criteria also yielded high specificity. Among supporting features, rapid progression was most important for predicting MSA pathology. The MDS criteria showed high specificity with clinically established MSA and moderate sensitivity and specificity with clinically probable MSA. The observation that high specificity could be achieved with clinical features alone suggests that MSA diagnosis with high specificity is possible even in areas where MRI is not readily available.

Serum lipid levels are associated with orthostatic hypotension in multiple system atrophy patients

ObjectivesOrthostatic hypotension (OH) is one of the most important autonomic features of multiple system atrophy (MSA). This study was established to confirm the correlation between lipid levels and OH in MSA. MethodsA total of 580 patients with probable or possible MSA from neurological wards in six hospitals in Tianjin, Beijing, Hebei Province, and Henan Province, China, were included in this study. The tilt test or stand test was used to assess the severity of OH. Lipid contents, including total cholesterol, low-density-lipoprotein cholesterol (LDL-C), high-density-lipoprotein cholesterol (HDL-C), and triglyceride were evaluated. ResultsSerum levels of total cholesterol, LDL-C, and triglyceride in MSA-OH patients were significantly lower than those in MSA without OH. The risks of OH were significantly higher in the lowest quartiles of triglyceride and LDL-C than in the highest quartiles, after adjusting for confounders (OR = 2.17, 95% CI: 1.23–3.82, P = 0.008 and OR = 2.02, 95% CI: 1.16–3.47, P = 0.012). The risk of severe OH was significantly higher in the lowest quartile and the second quartile of triglyceride than in the highest quartile after adjusting for confounders (OR = 2.16, 95% CI: 1.20–3.87, P = 0.010 and OR = 2.25, 95% CI: 1.24–4.07, P = 0.007). Moreover, the risk of OH was significantly higher in the lowest quartile, and the third quartile of TC than in the highest quartile after adjusting for confounders (OR = 2.04, 95% CI: 1.18–3.52, P = 0.010 and OR = 2.06, 95% CI: 1.19–3.56, P = 0.010). ConclusionLow levels of TC, LDL-C, and triglyceride increased the risk of OH in MSA. A low level of triglyceride predicted severe OH in MSA.

Diagnostic utility of movement disorder society criteria for multiple system atrophy.

The 2008 criteria for the diagnosis of multiple system atrophy (MSA) has been widely used for more than 10 years, but the sensitivity is low, particularly for patients in the early stage. Recently, a new MSA diagnostic criteria was developed. The objective of the study was to assess and compare the diagnostic utility of the new movement disorder society (MDS) MSA criteria with the 2008 MSA criteria. This study included patients diagnosed with MSA between January 2016 and October 2021. All patients underwent regular face-to-face or telephonic follow-ups every year until October 2022. A total of 587 patients (309 males and 278 females) were retrospectively reviewed to compare the diagnostic accuracy of the MDS MSA criteria to that of the 2008 MSA criteria (determined by the proportion of patients categorized as established or probable MSA). Autopsy is the gold standard diagnosis of MSA, which is not available in clinical practice. Thus, we applied the 2008 MSA criteria at the last review as the reference standard. The sensitivity of the MDS MSA criteria (93.2%, 95% CI = 90.5-95.2%) was significantly higher than that of the 2008 MSA criteria (83.5%, 95% CI = 79.8-86.6%) (P < 0.001). Additionally, the sensitivity of the MDS MSA criteria was maintained robustly across different subgroups, defined by diagnostic subtype, disease duration, and the type of symptom[s] at onset. Importantly, the specificities were not significantly different between the MDS MSA criteria and the 2008 MSA criteria (P > 0.05). The present study demonstrated that the MDS MSA criteria exhibited good diagnostic utility for MSA. The new MDS MSA criteria should be considered as a useful diagnostic tool for clinical practice and future therapeutic trials.

Constipation in multiple system atrophy: a pilot study in Chinese patients.

This study aimed to investigate the prevalence and clinical characteristics of subjective constipation in Chinese patients with multiple system atrophy (MSA), as well as the timing of constipation onset relative to the occurrence of motor symptoms. A total of 200 patients who were consecutively admitted to two large Chinese hospitals from February 2016 to June 2021 and subsequently diagnosed with probable MSA were enrolled in this cross-sectional study. Demographic and constipation-related clinical data were collected, and motor and non-motor symptoms were assessed using various scales and questionnaires. Subjective constipation was defined using ROME III criteria. The frequency of constipation was 53.5, 59.7, and 39.3% in MSA, MSA with predominately parkinsonism (MSA-P), and MSA with predominately cerebellar ataxia (MSA-C), respectively. MSA-P subtype and high total UMSARS scores were associated with constipation in MSA. Similarly, the high total UMSARS scores were associated with constipation in MSA-P and MSA-C patients. Among the 107 patients with constipation, 59.8% began experiencing it before the onset of motor symptoms, and the interval between constipation and occurrence of motor symptoms was significantly longer in these patients than in those who experienced constipation after onset of motor symptoms. Constipation is a highly prevalent non-motor symptom in MSA and more often occurs before the onset of motor symptoms. The results of this study may help guide future research into MSA pathogenesis in its earliest stages.

Freezing of gait in Chinese patients with multiple system atrophy: prevalence and risk factors.

Freezing of gait (FOG) is common in neurodegenerative forms of atypical parkinsonism, but few studies have examined FOG in multiple system atrophy (MSA). In this study, we examined the prevalence of freezing of gait and its relationship to clinical features in a large cohort of Chinese MSA patients. This exploratory study included 202 Chinese patients with probable MSA. FOG was defined as a score ≥ 1 on item 14 of the Unified Parkinson's Disease Rating Scale. Patients with or without FOG were compared in terms of the Unified MSA Rating Scale (UMSARS) as well as cognitive and neuropsychiatric assessments. The frequency of FOG was 48.0, 52.1, and 38.7% in MSA, MSA with predominant parkinsonism (MSA-P), and MSA with predominant cerebellar ataxia (MSA-C), respectively. FOG was associated with worse subscores on parts I, II and IV of the UMSARS as well as worse total UMSARS score; greater likelihood of speech difficulties, falls, gait impairment and balance disorder; more severe symptoms of anxiety and depression; and lower activities of daily living. The binary logistic regression model indicated that higher total UMSARS scores were associated with FOG in MSA, MSA-P, and MSA-C patients. Freezing of gait may be common among Chinese MSA patients, FOG may correlate with severe motor symptoms, anxiety, depression and activities of daily living. Total UMSARS score may be an independent risk factor for FOG.

Characteristics of Mild Cognitive Impairment and Associated Factors in MSA Patients

Mild cognitive impairment (MCI) in multiple-system atrophy (MSA) patients is common but remains poorly characterized, and the related factors are unclear. This retrospective study included 200 consecutive patients with a clinical diagnosis of possible or probable MSA, 102 MSA patients with MCI (MSA-MCI), and 98 MSA patients with normal cognition (MSA-NC). Cognitive profiles were compared between MSA-MCI and MSA-NC patients using the MoCA. In addition, demographic as well as major motor and nonmotor symptom differences were compared between MSA-MCI and MSA-NC patients. The median MMSE score was 26 points. Overall, MSA-MCI was observed in 51% of patients, with predominant impairment in visuospatial, executive, and attention functions compared with MSA-NC patients. MSA-MCI patients were older (p = 0.015) and had a later onset age (p = 0.024) and a higher frequency of hypertension, motor onset, and MSA with the predominant parkinsonism (MSA-P) phenotype than MSA-NC patients. The positive rate of orthostatic hypotension (OH) in MSA-MCI patients was significantly decreased and depression/anxiety was significantly increased compared with MSA-NC patients (p = 0.004). Multivariate logistic analysis showed that motor onset was independently associated with MCI in MSA patients. MSA-MCI patients had impairment in visuospatial, executive, and attention functions. More prominent memory impairment was observed in MSA-P than in MSA-C patients. Motor onset was independently associated with MCI in MSA patients. MCI was commonly presented in MSA with more prominent memory impairment in MSA-P. Future follow-up studies are warranted to identify more factors that influence cognitive impairment in MSA.

Factors impacting quality of life in multiple system atrophy.

Multiple system atrophy (MSA) is an atypical parkinsonian disorder marked by autonomic dysfunction, parkinsonism, cerebellar dysfunction, and poor response to dopaminergic medications such as levodopa. Patient-reported quality of life is an important benchmark for clinicians and clinical trials. The Unified Multiple System Atrophy Rating Scale (UMSARS) allows healthcare providers to rate and assess MSA progression. The MSA-QoL questionnaire is a health-related quality of life scale intended to provide patient-reported outcome measures. In this article, we investigated inter-scale correlations between the MSA-QoL and UMSARS to determine factors impacting the quality of life of patients with MSA. Twenty patients at the Johns Hopkins Atypical Parkinsonism Center's Multidisciplinary Clinic with a diagnosis of clinically probable MSA and who filled out the MSA-QoL and UMSARS questionnaires within 2 weeks of each other were included. Inter-scale correlations between MSA-QoL and UMSARS responses were examined. Linear regressions were also performed to examine relationships between both scales. Significant inter-scale correlations were found between the MSA-QoL and UMSARS, both between MSA-QoL total score and UMSARS Part I subtotal scores and for individual scale items. There were no significant correlations between MSA-QoL life satisfaction rating and UMSARS subtotal scores or any specific UMSARS items. Linear regression analysis found significant associations between MSA-QoL total score and UMSARS Part I and total scores, and between MSA-QoL life satisfaction rating and UMSARS Part I, Part II, and total scores (after adjustment for age). Our study demonstrates significant inter-scale correlations between MSA-QoL and UMSARS, particularly relating to activities of daily living and hygiene. MSA-QoL total score and UMSARS Part I subtotal scores, which assess patients' functional status, were significantly correlated. The lack of significant associations between MSA-QoL life satisfaction rating and any UMSARS item suggests there may be aspects to quality of life that are not fully captured by this assessment. Larger cross-sectional and longitudinal analyses utilizing UMSARS and MSA-QoL are warranted and modification of the UMSARS should be considered.

Phosphorylated α-synuclein in skin Schwann cells: a new biomarker for multiple system atrophy.

Multiple system atrophy (MSA) is characterized by accumulation of phosphorylated α-synuclein (p-syn) as glial cytoplasmic inclusions in the brain and a specific biomarker for this disorder is urgently needed. We aimed at investigating if p-syn can also be detected in skin Remak non-myelinating Schwann cells (RSCs) as Schwann cell cytoplasmic inclusions (SCCi) and may represent a reliable clinical biomarker for MSA. This cross-sectional diagnostic study evaluated skin p-syn in 96 patients: 46 with probable MSA (29 with parkinsonism type MSA and 17 with cerebellar type MSA), 34 with Parkinson's disease (PD) and 16 with dementia with Lewy bodies (DLB). We also included 50 healthy control subjects. Patients were recruited from five different medical centres. P-syn aggregates in skin sections were stained by immunofluorescence, followed by analyses with confocal microscopy and immuno-electron microscopy. All analyses were performed in a blinded fashion. Overall, p-syn aggregates were found in 78% of MSA patients and 100% of patients with PD/DLB, whereas they could not be detected in controls. As for neuronal aggregates 78% of MSA patients were positive for p-syn in somatic neurons, whereas all PD/DLB patients were positive in autonomic neurons. When analysing the presence of p-syn in RSCs, 74% of MSA patients were positive, whereas no such SCCi could be observed in PD/DLB patients. Analyses by immuno-electron microscopy confirmed that SCCi were only found in cases with MSA and thus absent in those with PD/DLB. In conclusion, our findings demonstrate that (i) fibrillar p-syn in RSCs is a pathological hallmark of MSA and may be used as a specific and sensitive disease biomarker; (ii) in Lewy body synucleinopathies (PD/DLB) only neurons contain p-syn deposits; and (iii) the cell-specific deposition of p-syn in the skin thus mirrors that of the brain in many aspects and suggests that non-myelinated glial cells are also involved in the MSA pathogenesis.

New MDS Criteria for the Diagnosis of Multiple System Atrophy: Overview and Genetic Viewpoint

A new diagnostic criteria for multiple system atrophy, "The Movement Disorder Society Criteria for the Diagnosis of Multiple System Atrophy (MSA)", has been proposed. Under the new criteria, new categories of "clinically established MSA," "clinically probable MSA," and "possible prodromal MSA" have been introduced. The new diagnostic criteria is expected to facilitate early and accurate diagnosis of MSA in clinical practice for MSA patients and clinical trials for MSA. In the diagnostic criteria, "A sporadic, progressive adult (>30 years) onset disease" is described as an "essential feature of MSA," and thus attention to familial occurrence of MSA is not included. Familial occurrence of MSA, however, was recognized first in Japan, and later in the world. We have witnessed discoveries of numerous genes underlying other neurodegenerative diseases, including Parkinson disease, and therefore application of molecular genetics research for MSA is highly expected to contribute to elucidating the molecular basis of MSA. Although the new diagnostic criteria is designed to facilitate early and accurate diagnosis of sporadic MSA, we simultaneously need to pay attention to familial occurrence of MSA and promotion of molecular genetics research of MSA.

New MDS Criteria for the Diagnosis of Multiple System Atrophy: How to Use in Clinical Practice and Clinical Trials

The newly revised diagnostic criteria for multiple system atrophy (MSA) have reduced the criteria for diagnosing orthostatic hypotension compared to the conventional diagnostic criteria, but require tests such as MRI and residual urine measurement. Under the new diagnostic criteria, cases that were previously classified as possible MSA with low diagnostic accuracy may become clinically established with higher diagnostic accuracy. However, examination of the cohort treated in our establishment showed that there were cases in which the diagnostic criteria could not be applied when the symptoms and test items necessary for diagnosis were not confirmed. In clinical trials, clinically established or clinically probable MSA are targeted for interventional studies, and possible prodromal MSA are considered to be more important for observational studies. In the future, it will be necessary to confirm the diagnostic accuracy pathologically, accumulate evidence from various clinical tests that are listed as supportive biomarkers, and to develop more useful diagnostic criteria.