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© 2014 Umeh et al.Background: Sex differences in Parkinson disease clinical features have been reported, but few studies have examined sex influences on use of dopaminergic medication in early Parkinson disease. The objective of this study was to test if t

Background: Sequence variants in coding and noncoding regions of THAP1 have been associated with primary dystonia.Methods: In this study, 1,446 Caucasian subjects with mainly adult-onset primary dystonia and 1,520 controls were genotyped for a variant located in the 5'-untranslated region of THAP1 (c.-237_236GA>TT).Results: Minor allele frequencies were 62/2892 (2.14%) and 55/3040 (1.81%) in subjects with dystonia and controls, respectively (P=0.202). Subgroup analyses by gender and anatomical distribution also failed to attain statistical significance. In addition, there was no effect of the TT variant on expression levels of THAP1 transcript or protein.Discussion: Our findings indicate that the c.-237_236GA>TT THAP1 sequence variant does not increase risk for adult-onset primary dystonia in Caucasians. [ABSTRACT FROM AUTHOR]

Background: Levodopa-induced dyskinesia (LID) is a common adverse effect of levodopa, one of the main therapeutics used to treat the motor symptoms of Parkinson's disease (PD). Previous evidence suggests a connection between LID and a disruption of the dopaminergic system as well as genes implicated in PD, including GBA1 and LRRK2., Objectives: Our goal was to investigate the effects of genetic variants on risk and time to LID., Methods: We performed a genome-wide association study (GWAS) and analyses focused on GBA1 and LRRK2 variants. We also calculated polygenic risk scores (PRS) including risk variants for PD and variants in genes involved in the dopaminergic transmission pathway. To test the influence of genetics on LID risk we used logistic regression, and to examine its impact on time to LID we performed Cox regression including 1612 PD patients with and 3175 without LID., Results: We found that GBA1 variants were associated with LID risk (odds ratio [OR] = 1.65; 95% confidence interval [CI], 1.21-2.26; P = 0.0017) and LRRK2 variants with reduced time to LID onset (hazard ratio [HR] = 1.42; 95% CI, 1.09-1.84; P = 0.0098). The fourth quartile of the PD PRS was associated with increased LID risk (OR fourth_quartile  = 1.27; 95% CI, 1.03-1.56; P = 0.0210). The third and fourth dopamine pathway PRS quartiles were associated with a reduced time to development of LID (HR third_quartile = 1.38; 95% CI, 1.07-1.79; P = 0.0128; HR fourth_quartile = 1.38; 95% CI = 1.06-1.78; P = 0.0147)., Conclusions: This study suggests that variants implicated in PD and in the dopaminergic transmission pathway play a role in the risk/time to develop LID. Further studies will be necessary to examine how these findings can inform clinical care. © 2024 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society., (© 2024 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.)

In 2011, the UK medical research charity Cure Parkinson's set up the international Linked Clinical Trials (iLCT) committee to help expedite the clinical testing of potentially disease modifying therapies for Parkinson's disease (PD). The first committee meeting was held at the Van Andel Institute in Grand Rapids, Michigan in 2012. This group of PD experts has subsequently met annually to assess and prioritize agents that may slow the progression of this neurodegenerative condition, using a systematic approach based on preclinical, epidemiological and, where possible, clinical data. Over the last 12 years, 171 unique agents have been evaluated by the iLCT committee, and there have been 21 completed clinical studies and 20 ongoing trials associated with the initiative. In this review, we briefly outline the iLCT process as well as the clinical development and outcomes of some of the top prioritized agents. We also discuss a few of the lessons that have been learnt, and we conclude with a perspective on what the next decade may bring, including the introduction of multi-arm, multi-stage clinical trial platforms and the possibility of combination therapies for PD.

Background: Vacuolar protein sorting 13 homolog A (VPS13A) disease, historically known as chorea-acanthocytosis, is a rare neurodegenerative disorder caused by biallelic mutations in VPS13A, usually resulting in reduced or absent levels of its protein product, VPS13A. VPS13A localizes to contact sites between subcellular organelles, consistent with its recently identified role in lipid transfer between membranes. Mutations are associated with neuronal loss in the striatum, most prominently in the caudate nucleus, and associated marked astrogliosis. There are no other known disease-specific cellular changes (eg, protein aggregation), but autopsy reports to date have been limited, often lacking genetic or biochemical diagnostic confirmation., Objective: The goal of this study was to characterize neuropathological findings in the brains of seven patients with VPS13A disease (chorea-acanthocytosis)., Methods: In this study, we collected brain tissues and clinical data from seven cases of VPS13A for neuropathological analysis. The clinical diagnosis was confirmed by the presence of VPS13A mutations and/or immunoblot showing the loss or reduction of VPS13A protein. Tissues underwent routine, special, and immunohistochemical staining focused on neurodegeneration. Electron microscopy was performed in one case., Results: Gross examination showed severe striatal atrophy. Microscopically, there was neuronal loss and astrogliosis in affected regions. Luxol fast blue staining showed variable lipid accumulation with diverse morphology, which was further characterized by electron microscopy. In some cases, rare degenerating p62- and ubiquitin-positive cells were present in affected regions. Calcifications were present in four cases, being extensive in one., Conclusions: We present the largest autopsy series of biochemically and genetically confirmed VPS13A disease and identify novel histopathological findings implicating abnormal lipid accumulation. © 2023 International Parkinson and Movement Disorder Society., (© 2023 International Parkinson and Movement Disorder Society.)

Mutations in SNCA, the gene encoding α-synuclein (αSyn), cause familial Parkinson's disease (PD) and aberrant αSyn is a key pathological hallmark of idiopathic PD. This α-synucleinopathy leads to mitochondrial dysfunction, which may drive dopaminergic neurodegeneration. PARKIN and PINK1, mutated in autosomal recessive PD, regulate the preferential autophagic clearance of dysfunctional mitochondria ("mitophagy") by inducing ubiquitylation of mitochondrial proteins, a process counteracted by deubiquitylation via USP30. Here we show that loss of USP30 in Usp30 knockout mice protects against behavioral deficits and leads to increased mitophagy, decreased phospho-S129 αSyn, and attenuation of SN dopaminergic neuronal loss induced by αSyn. These observations were recapitulated with a potent, selective, brain-penetrant USP30 inhibitor, MTX115325, with good drug-like properties. These data strongly support further study of USP30 inhibition as a potential disease-modifying therapy for PD., (© 2023. The Author(s).)

Parkinson's Disease (PD) is characterized by the progressive loss of dopaminergic neurons in the substantia nigra (SN), leading to motor and non-motor symptoms. While the exact mechanisms remain complex and multifaceted, several molecular pathways have been implicated in PD pathology, including accumulation of misfolded proteins, impaired mitochondrial function, oxidative stress, inflammation, elevated iron levels, etc. Overall, PD's molecular mechanisms involve a complex interplay between genetic, environmental, and cellular factors that disrupt cellular homeostasis, and ultimately lead to the degeneration of dopaminergic neurons. Recently, emerging evidence highlights ferroptosis, an iron-dependent non-apoptotic cell death process, as a pivotal player in the advancement of PD. Notably, oligomeric α-synuclein (α-syn) generates reactive oxygen species (ROS) and lipid peroxides within cellular membranes, potentially triggering ferroptosis. The loss of dopamine, a hallmark of PD, could predispose neurons to ferroptotic vulnerability. This unique form of cell demise unveils fresh insights into PD pathogenesis, necessitating an exploration of the molecular intricacies connecting ferroptosis and PD progression. In this review, the molecular and regulatory mechanisms of ferroptosis and their connection with the pathological processes of PD have been systematically summarized. Furthermore, the features of ferroptosis in PD animal models and clinical trials targeting ferroptosis as a therapeutic approach in PD patients' management are scrutinized., Competing Interests: Declaration of Competing Interest The authors declare that they have no competing interests., (Copyright © 2023. Published by Elsevier B.V.)

Background: Chorea-acanthocytosis (ChAc) is associated with mutations of VPS13A, which encodes for chorein, a protein implicated in lipid transport at intracellular membrane contact sites., Objectives: The goal of this study was to establish the lipidomic profile of patients with ChAc., Methods: We analyzed 593 lipid species in the caudate nucleus (CN), putamen, and dorsolateral prefrontal cortex (DLPFC) from postmortem tissues of four patients with ChAc and six patients without ChAc., Results: We found increased levels of bis(monoacylglycerol)phosphate, sulfatide, lysophosphatidylserine, and phosphatidylcholine ether in the CN and putamen, but not in the DLPFC, of patients with ChAc. Phosphatidylserine and monoacylglycerol were increased in the CN and N-acyl phosphatidylserine in the putamen. N-acyl serine was decreased in the CN and DLPFC, whereas lysophosphatidylinositol was decreased in the DLPFC., Conclusions: We present the first evidence of altered sphingolipid and phospholipid levels in the brains of patients with ChAc. Our observations are congruent with recent findings in cellular and animal models, and implicate defects of lipid processing in VPS13A disease pathophysiology. © 2023 International Parkinson and Movement Disorder Society. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA., (© 2023 International Parkinson and Movement Disorder Society. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.)

Background: Aggregated α-synuclein plays an important role in Parkinson's disease pathogenesis. Cinpanemab, a human-derived monoclonal antibody that binds to α-synuclein, is being evaluated as a disease-modifying treatment for Parkinson's disease., Methods: In a 52-week, multicenter, double-blind, phase 2 trial, we randomly assigned, in a 2:1:2:2 ratio, participants with early Parkinson's disease to receive intravenous infusions of placebo (control) or cinpanemab at a dose of 250 mg, 1250 mg, or 3500 mg every 4 weeks, followed by an active-treatment dose-blinded extension period for up to 112 weeks. The primary end points were the changes from baseline in the Movement Disorder Society-sponsored revision of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS) total score (range, 0 to 236, with higher scores indicating worse performance) at weeks 52 and 72. Secondary end points included MDS-UPDRS subscale scores and striatal binding as assessed on dopamine transporter single-photon-emission computed tomography (DaT-SPECT)., Results: Of the 357 enrolled participants, 100 were assigned to the control group, 55 to the 250-mg cinpanemab group, 102 to the 1250-mg group, and 100 to the 3500-mg group. The trial was stopped after the week 72 interim analysis owing to lack of efficacy. The change to week 52 in the MDS-UPDRS score was 10.8 points in the control group, 10.5 points in the 250-mg group, 11.3 points in the 1250-mg group, and 10.9 points in the 3500-mg group (adjusted mean difference vs. control, -0.3 points [95% confidence interval {CI}, -4.9 to 4.3], P = 0.90; 0.5 points [95% CI, -3.3 to 4.3], P = 0.80; and 0.1 point [95% CI, -3.8 to 4.0], P = 0.97, respectively). The adjusted mean difference at 72 weeks between participants who received cinpanemab through 72 weeks and the pooled group of those who started cinpanemab at 52 weeks was -0.9 points (95% CI, -5.6 to 3.8) for the 250-mg dose, 0.6 points (95% CI, -3.3 to 4.4) for the 1250-mg dose, and -0.8 points (95% CI, -4.6 to 3.0) for the 3500-mg dose. Results for secondary end points were similar to those for the primary end points. DaT-SPECT imaging at week 52 showed no differences between the control group and any cinpanemab group. The most common adverse events with cinpanemab were headache, nasopharyngitis, and falls., Conclusions: In participants with early Parkinson's disease, the effects of cinpanemab on clinical measures of disease progression and changes in DaT-SPECT imaging did not differ from those of placebo over a 52-week period. (Funded by Biogen; SPARK ClinicalTrials.gov number, NCT03318523.)., (Copyright © 2022 Massachusetts Medical Society.)

Introduction: Despite evidence of the benefits of exercise, people with Parkinson's disease (PD) often exercise less than recommended. We sought to identify exercise class-related factors associated with the amount of exercise in PD communities., Methods: We used Parkinson's Outcome Project (POP) data from 3146 people with PD at 19 participating Centers of Excellence (COEs). POP data included self-reported moderate-vigorous exercise (MVE) hours, light physical activity (PA) hours, demographic and disease severity variables. We also collected information about weekly exercise class availability, intensity, cost, and distance from class location to the COE. We examined differences between COE-based and community-based exercise classes using the Akritas test for paired and unpaired samples. We tested associations between class characteristics and exercise hours based on a two-part model: logistic regression on whether a participant does MVE or light PA and linear regression for log-transformed time of exercise., Results: Community-based exercise classes had a significantly higher weekly availability than COE-based classes (class hours per week: 47.5 ± 25.6 vs 6.5 ± 8.6, p < 0.001), a higher percentage of vigorous-intensity classes (24.2 ± 17.8 vs 11 ± 14.7, p < 0.001), and a broader geographic distribution (miles to COE: 12.8 ± 4.6 vs 6.2 ± 5.7, p < 0.001). Greater weekly hours of availability, intensity, and distance to COE were associated with increased MVE and light PA hours among participants who exercised (p < 0.01). Of these, higher weekly class availability explained the most variability in reported exercise hours., Conclusion: Parkinson's COEs may be able to increase exercise by facilitating a high weekly availability of exercise classes with higher intensity levels and broader geographical distribution., (© 2022 The Authors.)

Importance: Urate elevation, despite associations with crystallopathic, cardiovascular, and metabolic disorders, has been pursued as a potential disease-modifying strategy for Parkinson disease (PD) based on convergent biological, epidemiological, and clinical data., Objective: To determine whether sustained urate-elevating treatment with the urate precursor inosine slows early PD progression., Design, Participants, and Setting: Randomized, double-blind, placebo-controlled, phase 3 trial of oral inosine treatment in early PD. A total of 587 individuals consented, and 298 with PD not yet requiring dopaminergic medication, striatal dopamine transporter deficiency, and serum urate below the population median concentration (<5.8 mg/dL) were randomized between August 2016 and December 2017 at 58 US sites, and were followed up through June 2019., Interventions: Inosine, dosed by blinded titration to increase serum urate concentrations to 7.1-8.0 mg/dL (n = 149) or matching placebo (n = 149) for up to 2 years., Main Outcomes and Measures: The primary outcome was rate of change in the Movement Disorder Society Unified Parkinson Disease Rating Scale (MDS-UPDRS; parts I-III) total score (range, 0-236; higher scores indicate greater disability; minimum clinically important difference of 6.3 points) prior to dopaminergic drug therapy initiation. Secondary outcomes included serum urate to measure target engagement, adverse events to measure safety, and 29 efficacy measures of disability, quality of life, cognition, mood, autonomic function, and striatal dopamine transporter binding as a biomarker of neuronal integrity., Results: Based on a prespecified interim futility analysis, the study closed early, with 273 (92%) of the randomized participants (49% women; mean age, 63 years) completing the study. Clinical progression rates were not significantly different between participants randomized to inosine (MDS-UPDRS score, 11.1 [95% CI, 9.7-12.6] points per year) and placebo (MDS-UPDRS score, 9.9 [95% CI, 8.4-11.3] points per year; difference, 1.26 [95% CI, -0.59 to 3.11] points per year; P = .18). Sustained elevation of serum urate by 2.03 mg/dL (from a baseline level of 4.6 mg/dL; 44% increase) occurred in the inosine group vs a 0.01-mg/dL change in serum urate in the placebo group (difference, 2.02 mg/dL [95% CI, 1.85-2.19 mg/dL]; P<.001). There were no significant differences for secondary efficacy outcomes including dopamine transporter binding loss. Participants randomized to inosine, compared with placebo, experienced fewer serious adverse events (7.4 vs 13.1 per 100 patient-years) but more kidney stones (7.0 vs 1.4 stones per 100 patient-years)., Conclusions and Relevance: Among patients recently diagnosed as having PD, treatment with inosine, compared with placebo, did not result in a significant difference in the rate of clinical disease progression. The findings do not support the use of inosine as a treatment for early PD., Trial Registration: ClinicalTrials.gov Identifier: NCT02642393.

Importance: There is a critical need for careful and independent validation of reported symptomatic efficacy and dopaminergic biomarker changes induced by nilotinib in Parkinson disease (PD)., Objectives: To assess safety and tolerability of nilotinib in participants with moderately advanced PD. Secondary and exploratory objectives were to assess its affect on PD disability, pharmacokinetics, cerebrospinal fluid (CSF) penetration, and biomarkers., Design, Setting, and Participants: This was a 6-month, multicenter, randomized parallel-group, double-blind, placebo-controlled trial. Recruitment was from November 20, 2017, to December 28, 2018, and follow-up ended on September 9, 2019. The study was conducted at 25 US sites. The study approached 173 patients, of whom 48 declined, 125 were screened, and 76 who received a stable regimen of PD medications were enrolled (39% screen failure)., Interventions: Participants were randomized 1:1:1 to placebo, 150-mg nilotinib, or 300-mg nilotinib once daily orally for 6 months, followed by 2-month off-drug evaluation., Main Outcomes and Measures: The primary outcomes were safety and tolerability. The tolerability end point was defined as the ability to complete the study while receiving the assigned dose. An active arm was considered tolerable if the percentage of participants meeting the tolerability end point for that group was not significantly lower than the percentage observed in the placebo group. Secondary outcomes included change in PD disability (Movement Disorder Society Unified Parkinson's Disease Rating Scale [MDS-UPDRS], Part II OFF/ON). Exploratory outcomes included serum and CSF pharmacokinetic profile, and CSF dopaminergic biomarkers., Results: At baseline, mean (SD) participants' age was 64.6 (7.5) years, 52 were male (68%), mean (SD) disease duration was 9.9 years (4.7), MDS-UPDRS Part 1-3 OFF score was 66.4 (19.3), ON score was 48.4 (16.2), and Montreal Cognitive Assessment score was 27.1 (2.2). The number of participants who completed the study receiving the assigned dose were 21 (84%), 19 (76%), and 20 (77%) in the placebo, 150-mg, and 300-mg arms, respectively. Both active doses had acceptable safety profile. The most common reasons for drug suspension were asymptomatic, dose-dependent elevations of amylase, and/or lipase. Nilotinib, 150 mg and 300 mg, exhibited worse MDS-UPDRS-3 ON scores compared with placebo, achieving significance for nilotinib, 300 mg, at month 1 (P < .01). There was no difference in the change of MDS-UPDRS-3 OFF from baseline to 6 months between groups (P = .17). Cerebrospinal fluid/serum ratio of nilotinib concentration was 0.2% to 0.3%. There was no evidence of treatment-related alteration of dopamine metabolites in the CSF., Conclusions and Relevance: While we demonstrated acceptable safety and tolerability of nilotinib in our cohort, the low CSF exposure and lack of biomarkers effect combined with the efficacy data trending in the negative direction indicate that nilotinib should not be further tested in PD., Trial Registration: ClinicalTrials.gov Identifier: NCT03205488.

Background: Previous studies reported various symptoms of Parkinson's disease (PD) associated with sex. Some were conflicting or confirmed in only one study., Objectives: We examined sex associations to PD phenotypes cross-sectionally and longitudinally in large-scale data., Methods: We tested 40 clinical phenotypes, using longitudinal, clinic-based patient cohorts, consisting of 5946 patients, with a median follow-up of 3.1 years. For continuous outcomes, we used linear regressions at baseline to test sex-associated differences in presentation, and linear mixed-effects models to test sex-associated differences in progression. For binomial outcomes, we used logistic regression models at baseline and Cox regression models for survival analyses. We adjusted for age, disease duration, and medication use. In the secondary analyses, data from 17 719 PD patients and 7588 non-PD participants from an online-only, self-assessment PD cohort were cross-sectionally evaluated to determine whether the sex-associated differences identified in the primary analyses were consistent and unique to PD., Results: Female PD patients had a higher risk of developing dyskinesia early during the follow-up period, with a slower progression in activities of daily living difficulties, and a lower risk of developing cognitive impairments compared with male patients. The findings in the longitudinal, clinic-based cohorts were mostly consistent with the results of the online-only cohort., Conclusions: We observed sex-associated contributions to PD heterogeneity. These results highlight the necessity of future research to determine the underlying mechanisms and importance of personalized clinical management. © 2020 International Parkinson and Movement Disorder Society., (© 2020 International Parkinson and Movement Disorder Society.)

Mutations in VPS35 (PARK17), a key molecule in the retromer complex, are a rare cause of autosomal dominant Parkinson's disease (PD), the second most common neurodegenerative disorder. VPS35 exerts crucial functions within the cell in terms of regulating endosomal trafficking. However new data suggest its relevance also in the regulation of mitochondrial dynamics and homeostasis. Herein, we review the crosstalk between VPS35 and the mitochondria, highlighting the potential relevance to PD pathogenesis. VPS35 is not only a critical player in pathways connected to α-synuclein accumulation and clearance, but also plays a key role in ensuring mitochondrial stability and function. The genetic links of VPS35 to PD and the involvement of VPS35 in different PD related pathological mechanisms highlight the potential for targeting VPS35 as a neuroprotective strategy for PD., Competing Interests: Declaration of Competing Interest G.C., S.E. and D.K.S have nothing to disclose., (Copyright © 2020. Published by Elsevier Inc.)

Parkinson disease is a complex, age-related, neurodegenerative disease associated with dopamine deficiency and both motor and nonmotor deficits. Many environmental and genetic factors influence Parkinson disease risk, with different factors predominating in different patients. These factors converge on specific pathways, including mitochondrial dysfunction, oxidative stress, protein aggregation, impaired autophagy, and neuroinflammation. Ultimately, treatment of Parkinson disease may focus on targeted therapies for pathophysiologically defined subtypes of Parkinson disease patients., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Introduction: Deep brain stimulation (DBS) surgery is an efficacious, underutilized treatment for Parkinson's disease (PD). Studies of DBS post-operative outcomes are often restricted to data from a single center and consider DBS in isolation. National estimates of DBS readmission and post-operative outcomes are needed, as are comparisons to commonly performed surgeries., Methods: This study used datasets from the 2013 and 2014 Nationwide Readmissions Database (NRD). Our sample was restricted to PD patients discharged alive after hospitalization for DBS surgery. Descriptive analyses examined patient, clinical, hospital and index hospitalization characteristics. The all-cause, non-elective 30-day readmission rate after DBS was calculated, and logistic regression models were built to examine factors associated with readmission. Readmission rates for the most common surgical procedures were calculated and compared to DBS., Results: There were 6058 DBS surgeries for PD in our sample, most often involving a male aged 65 and older, who lived in a high socioeconomic status zip code. DBS patients had an average of four comorbidities. With respect to outcomes, the majority of patients were discharged home (95.3%). Non-elective readmission was rare (4.9%), and was associated with socioeconomic status, comorbidity burden, and teaching hospital status. Much higher acute, non-elective readmission rates were observed for common procedures such as upper gastrointestinal endoscopy (16.2%), colonoscopy (14.0%), and cardiac defibrillator and pacemaker procedures (11.1%)., Conclusion: Short-term hospitalization outcomes after DBS are generally favorable. Socioeconomic disparities in DBS use persist. Additional efforts may be needed to improve provider referrals for and patient access to DBS., Competing Interests: Declaration of competing interest RBS: Has no conflicts of interest relevant to this work but reports grant support from the National Institute of Neurological Disorders and Stroke, Biohaven Pharmaceuticals, CHDI Foundation, Teva Pharmaceuticals, Pfizer, Nuredis Inc., The Michael J. Fox Foundation, and the Canadian Institute of Health Research as well as financial support from the Parkinson's Foundation. JJ-S: Reports research support from Medtronic and St. Jude Medical/Abbott as well as consulting agreements with Medtronic, St. Jude Medical/Abbott, and Boston Scientific relevant to this work. Also reports research support from Teva and Lilly; consulting agreements with Bracket and Nuvelution; and grant support from the National Institute of Neurological Disorders and Stroke, the Michael J. Fox Foundation, and the Simons Foundation. DSA: Has no conflicts of interest relevant to this work but reports research support from the National Institutes of Health and financial support from the Parkinson's Foundation. DPT: None. SM: None. MF: Has no conflicts of interest relevant to this work but reports active research funding from the American Academy of Neurology, American Brain Foundation, and the Parkinson's Foundation. MAB: Has no conflicts of interest relevant to this work but reports active research funding from the Parkinson's Foundation. KLC: Has no conflicts of interest relevant to this work but reports active research funds from the National Institutes of Health and the Parkinson Study Group, consulting agreements with Sunovion Pharmaceuticals, and royalties from UpToDate and Springer. MS: Has no conflicts of interest relevant to this work but reports active research funding from Abbvie, USWorldMeds, Sanofi, Lundbeck, and Abbott. WJJ: None. P-FD: Has no conflicts of interest relevant to this work but reports service as an Officer of Neurotargeting LLC. MKY: Has no conflicts of interest relevant to this work but reports personal compensation for consultant, Steering Committee, and Data Safety Monitoring Board service from the Michael J. Fox Foundation and Boston Scientific. JCK: None. JMS: Has no conflicts of interest relevant to this work but reports research grants from Medtronic, service as a consultant for Guidant, LLC, and salary support from Blue Cross Blue Shield of Michigan. AJE: Has no conflicts of interest relevant to this work but reports grant support from the National Institutes of Health, Great Lakes Neurotechnologies, and the Michael J Fox Foundation; personal compensation as a consultant/scientific advisory board member for Abbvie, Neuroderm, TEVA, Impax, Acadia, Acorda, Cynapsus/Sunovion, Lundbeck, Osmotica Pharmaceutical, and USWorldMeds; publishing royalties from Lippincott Williams & Wilkins, Cambridge University Press, and Springer; and honoraria from Abbvie, UCB, USWorldMeds, Lundbeck, Acadia, the American Academy of Neurology, and the Movement Disorders Society. LCS: Has no conflicts of interest relevant to this work but reports employment with Biogen, Inc. DKS: Has no conflicts of interest relevant to this work but reports research funding from BioElectron Technology, Lysosomal Therapeutics, Mission Therapeutics, Voyager Therapeutics, the Weston Brain Institute, and the National Institutes of Health as well as honorarium for Steering Committee service from the Michael J. Fox Foundation and Biogen. CH: None. JAGC: Has no conflicts of interest relevant to this work but reports research support from the Northern Ontario Academic Medicine Association. AWW: Has no conflicts of interest relevant to this work but reports research funding from the National Institutes of Health and the Parkinson's Foundation., (Copyright © 2019. Published by Elsevier Ltd.)

Background: Several reports have identified different patterns of Parkinson's disease progression in individuals carrying missense variants in GBA or LRRK2 genes. The overall contribution of genetic factors to the severity and progression of Parkinson's disease, however, has not been well studied., Objectives: To test the association between genetic variants and the clinical features of Parkinson's disease on a genomewide scale., Methods: We accumulated individual data from 12 longitudinal cohorts in a total of 4093 patients with 22,307 observations for a median of 3.81 years. Genomewide associations were evaluated for 25 cross-sectional and longitudinal phenotypes. Specific variants of interest, including 90 recently identified disease-risk variants, were also investigated post hoc for candidate associations with these phenotypes., Results: Two variants were genomewide significant. Rs382940(T>A), within the intron of SLC44A1, was associated with reaching Hoehn and Yahr stage 3 or higher faster (hazard ratio 2.04 [1.58-2.62]; P value = 3.46E-8). Rs61863020(G>A), an intergenic variant and expression quantitative trait loci for α-2A adrenergic receptor, was associated with a lower prevalence of insomnia at baseline (odds ratio 0.63 [0.52-0.75]; P value = 4.74E-8). In the targeted analysis, we found 9 associations between known Parkinson's risk variants and more severe motor/cognitive symptoms. Also, we replicated previous reports of GBA coding variants (rs2230288: p.E365K; rs75548401: p.T408M) being associated with greater motor and cognitive decline over time, and an APOE E4 tagging variant (rs429358) being associated with greater cognitive deficits in patients., Conclusions: We identified novel genetic factors associated with heterogeneity of Parkinson's disease. The results can be used for validation or hypothesis tests regarding Parkinson's disease. © 2019 International Parkinson and Movement Disorder Society., (© 2019 International Parkinson and Movement Disorder Society.)

Introduction: Improved methods are needed to detect and quantify age-related muscle change. In this study we assessed the electrical properties of muscle impacted by acquired mitochondrial DNA mutations via the PolG mouse, which exhibits typical age-associated features, and the impact of a potential therapy, nicotinamide mononucleotide (NMN)., Methods: The gastrocnemii of 24 PolG and 30 wild-type (WT) mice (8 PolG and 17 WT treated with NMN) were studied in an electrical impedance-measuring cell. Conductivity and relative permittivity were determined from the impedance data. Myofiber cross-sectional area (CSA) was quantified histologically., Results: Untreated PolG mice demonstrated alterations in several impedance features, including 50-kHz relative permittivity and center frequency. A potential effect of NMN was also observed in these parameters in PolG but not WT animals. Impedance values correlated with myofiber CSA., Discussion: Electrical impedance is sensitive to myofiber features considered characteristic of aging and to the impact of a potential therapy., (© 2019 Wiley Periodicals, Inc.)

Among the barriers to participation in clinical trials, transportation to and from study sites may be a prominent issue. Patients with Parkinson's disease have unique circumstances that add to the barriers including dementia, loss of driving ability, timing of medications, impact of reduced mobility, and bowel and bladder concerns. We sought to alleviate some of the burden of transportation by setting up pre-arranged rides through a third-party ride sharing service. This pilot project was established to assess feasibility and to explore the possibility that reducing the transportation burden may enhance participation in studies. One out of three academic sites was successful in setting up this service, and surveyed participants on the impact of this service. In general, study participants who opted into the ride-sharing service felt it made the process easier and less stressful. Most participants agreed that they are more likely to participate in another study if transportation was provided. This short-term pilot intervention suggests that participants were satisfied with a ride sharing service to help with their medical transportation needs, but larger studies that include data collection about retention are needed., (© 2019 The Authors. Published by Elsevier Inc.)

Objective: To determine if any association between previously identified alleles that confer risk for Parkinson disease and variables measuring disease progression., Methods: We evaluated the association between 31 risk variants and variables measuring disease progression. A total of 23,423 visits by 4,307 patients of European ancestry from 13 longitudinal cohorts in Europe, North America, and Australia were analyzed., Results: We confirmed the importance of GBA on phenotypes. GBA variants were associated with the development of daytime sleepiness (p.N370S: hazard ratio [HR] 3.28 [1.69-6.34]) and possible REM sleep behavior (p.T408M: odds ratio 6.48 [2.04-20.60]). We also replicated previously reported associations of GBA variants with motor/cognitive declines. The other genotype-phenotype associations include an intergenic variant near LRRK2 and the faster development of motor symptom (Hoehn and Yahr scale 3.0 HR 1.33 [1.16-1.52] for the C allele of rs76904798) and an intronic variant in PMVK and the development of wearing-off effects (HR 1.66 [1.19-2.31] for the C allele of rs114138760). Age at onset was associated with TMEM175 variant p.M393T (-0.72 [-1.21 to -0.23] in years), the C allele of rs199347 (intronic region of GPNMB , 0.70 [0.27-1.14]), and G allele of rs1106180 (intronic region of CCDC62 , 0.62 [0.21-1.03])., Conclusions: This study provides evidence that alleles associated with Parkinson disease risk, in particular GBA variants, also contribute to the heterogeneity of multiple motor and nonmotor aspects. Accounting for genetic variability will be a useful factor in understanding disease course and in minimizing heterogeneity in clinical trials.

The gold standard for a definitive diagnosis of Parkinson disease (PD) is the pathologic finding of aggregated α-synuclein into Lewy bodies and for Alzheimer disease (AD) aggregated amyloid into plaques and hyperphosphorylated tau into tangles. Implicit in this clinicopathologic-based nosology is the assumption that pathologic protein aggregation at autopsy reflects pathogenesis at disease onset. While these aggregates may in exceptional cases be on a causal pathway in humans (e.g., aggregated α-synuclein in SNCA gene multiplication or aggregated β-amyloid in APP mutations), their near universality at postmortem in sporadic PD and AD suggests they may alternatively represent common outcomes from upstream mechanisms or compensatory responses to cellular stress in order to delay cell death. These 3 conceptual frameworks of protein aggregation (pathogenic, epiphenomenon, protective) are difficult to resolve because of the inability to probe brain tissue in real time. Whereas animal models, in which neither PD nor AD occur in natural states, consistently support a pathogenic role of protein aggregation, indirect evidence from human studies does not. We hypothesize that (1) current biomarkers of protein aggregates may be relevant to common pathology but not to subgroup pathogenesis and (2) disease-modifying treatments targeting oligomers or fibrils might be futile or deleterious because these proteins are epiphenomena or protective in the human brain under molecular stress. Future precision medicine efforts for molecular targeting of neurodegenerative diseases may require analyses not anchored on current clinicopathologic criteria but instead on biological signals generated from large deeply phenotyped aging populations or from smaller but well-defined genetic-molecular cohorts., (© 2019 American Academy of Neurology.)

Doubly truncated data arise when event times are observed only if they fall within subject-specific, possibly random, intervals. While non-parametric methods for survivor function estimation using doubly truncated data have been intensively studied, only a few methods for fitting regression models have been suggested, and only for a limited number of covariates. In this article, we present a method to fit the Cox regression model to doubly truncated data with multiple discrete and continuous covariates, and describe how to implement it using existing software. The approach is used to study the association between candidate single nucleotide polymorphisms and age of onset of Parkinson's disease., (© 2017, The International Biometric Society.)

Several molecular pathways are currently being targeted in attempts to develop disease-modifying therapies to slow down neurodegeneration in Parkinson's disease. Failure of cellular energy metabolism has long been implicated in sporadic Parkinson's disease and recent research on rare inherited forms of Parkinson's disease have added further weight to the importance of energy metabolism in the disease pathogenesis. There exists a new class of anti-diabetic insulin sensitizers in development that inhibit the mitochondrial pyruvate carrier (MPC), a protein which mediates the import of pyruvate across the inner membrane of mitochondria. Pharmacological inhibition of the MPC was recently found to be strongly neuroprotective in multiple neurotoxin-based and genetic models of neurodegeneration which are relevant to Parkinson's disease. In this review, we summarize the neuroprotective effects of MPC inhibition and discuss the potential putative underlying mechanisms. These mechanisms involve augmentation of autophagy via attenuation of the activity of the mammalian target of rapamycin (mTOR) in neurons, as well as the inhibition of neuroinflammation, which is at least partly mediated by direct inhibition of MPC in glia cells. We conclude that MPC is a novel and potentially powerful therapeutic target that warrants further study in attempts to slow Parkinson's disease progression.

Objective: To explore the association between metabolic syndrome and the Unified Parkinson's Disease Rating Scale (UPDRS) scores and, secondarily, the Symbol Digit Modalities Test (SDMT)., Methods: This is a secondary analysis of data from 1,022 of 1,741 participants of the National Institute of Neurological Disorders and Stroke Exploratory Clinical Trials in Parkinson Disease Long-Term Study 1, a randomized, placebo-controlled trial of creatine. Participants were categorized as having or not having metabolic syndrome on the basis of modified criteria from the National Cholesterol Education Program Adult Treatment Panel III. Those who had the same metabolic syndrome status at consecutive annual visits were included. The change in UPDRS and SDMT scores from randomization to 3 years was compared in participants with and without metabolic syndrome., Results: Participants with metabolic syndrome (n = 396) compared to those without (n = 626) were older (mean [SD] 63.9 [8.1] vs 59.9 [9.4] years; p < 0.0001), were more likely to be male (75.3% vs 57.0%; p < 0.0001), and had a higher mean uric acid level (men 5.7 [1.3] vs 5.3 [1.1] mg/dL, women 4.9 [1.3] vs 3.9 [0.9] mg/dL, p < 0.0001). Participants with metabolic syndrome experienced an additional 0.6- (0.2) unit annual increase in total UPDRS ( p = 0.02) and 0.5- (0.2) unit increase in motor UPDRS ( p = 0.01) scores compared with participants without metabolic syndrome. There was no difference in the change in SDMT scores., Conclusions: Persons with Parkinson disease meeting modified criteria for metabolic syndrome experienced a greater increase in total UPDRS scores over time, mainly as a result of increases in motor scores, compared to those who did not. Further studies are needed to confirm this finding., Clinicaltrialsgov Identifier: NCT00449865., (© 2017 American Academy of Neurology.)

Parkinson disease (PD) is a progressive neurodegenerative disorder characterized by motor and non-motor symptoms and signs. Many reports suggest that diminished heart rate variability occurs early, even prior to the cardinal signs of PD. In a longitudinal study of PD, we evaluated whether heart rate variability (HRV) obtained using a 10-second ECG tracing, and the electrocardiographic QT-interval would be associated with PD severity and progression. Subjects were derived from a longitudinal study of 1741 individuals with early, stable PD. The severity of PD was measured using the global statistical test (GST). In a subset, the heart rate corrected QT-interval (QTcB) was calculated for each electrocardiogram (ECG). The HRV was measured for each ECG and then transformed to fit a normal distribution. The baseline analysis included 653 subjects, with 256 completing the 5-year follow up study. There was an association (P<0.05) between QTcB and PD severity in individuals that were taking QT-interval affecting drugs. A longer QT-interval at baseline was associated with more advanced PD at 5years (P<0.05), and greater disease progression over 5years (P<0.05). There was an association between diminished HRV and an orthostatic decrease in standing blood pressure at baseline in individuals with PD (P<0.05). HRV was not associated with PD severity or progression. In conclusion, we were able to detect measurable associations between the QTcB interval and PD severity, PD severity 5years later, and the change in disease over time. However, routine ECG tracings appear inadequate for the evaluation of autonomic function in PD., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Background: Recognizing the factors associated with falling in Parkinson's disease (PD) would improve identification of at-risk individuals., Objective: To examine frequency of falling and baseline characteristics associated with falling in PD using the National Institute of Neurological Disorders and Stroke (NINDS) Exploratory Trials in PD Long-term Study-1 (NET-PD LS-1) dataset., Methods: The LS-1 database included 1741 early treated PD subjects (median 4year follow-up). Baseline characteristics were tested for a univariate association with post-baseline falling during the trial. Significant variables were included in a multivariable logistic regression model. A separate analysis using a negative binomial model investigated baseline factors on fall rate., Results: 728 subjects (42%) fell during the trial, including at baseline. A baseline history of falls was the factor most associated with post-baseline falling. Men had lower odds of post-baseline falling compared to women, but for men, the probability of a post-baseline fall increased with age such that after age 70, men and women had similar odds of falling. Other baseline factors associated with a post-baseline fall and increased fall rate included the Unified PD Rating Scale (UPDRS) Activities of Daily Living (ADL) score, total functional capacity (TFC), baseline ambulatory capacity score and dopamine agonist monotherapy., Conclusion: Falls are common in early treated PD. The biggest risk factor for falls in PD remains a history of falling. Measures of functional ability (UPDRS ADL, TFC) and ambulatory capacity are novel clinical risk factors needing further study. A significant age by sex interaction may help to explain why age has been an inconsistent risk factor for falls in PD., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Caffeine is neuroprotective in animal models of Parkinson's disease (PD) and caffeine intake is inversely associated with the risk of PD. This association may be influenced by the genotype of GRIN2A, which encodes an NMDA-glutamate-receptor subunit. In two placebo-controlled studies, we detected no association of caffeine intake with the rate of clinical progression of PD, except among subjects taking creatine, for whom higher caffeine intake was associated with more rapid progression. We now have analyzed data from 420 subjects for whom DNA samples and caffeine intake data were available from a placebo-controlled study of creatine in PD. The GRIN2A genotype was not associated with the rate of clinical progression of PD in the placebo group. However, there was a 4-way interaction between GRIN2A genotype, caffeine, creatine and the time since baseline. Among subjects in the creatine group with high levels of caffeine intake, but not among those with low caffeine intake, the GRIN2A T allele was associated with more rapid progression (p=0.03). These data indicate that the deleterious interaction between caffeine and creatine with respect to rate of progression of PD is influenced by GRIN2A genotype. This example of a genetic factor interacting with environmental factors illustrates the complexity of gene-environment interactions in the progression of PD., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Past clinical trials of putative neuroprotective therapies have targeted PD as a single pathogenic disease entity. From an Oslerian clinicopathological perspective, the wide complexity of PD converges into Lewy bodies and justifies a reductionist approach to PD: A single-mechanism therapy can affect most of those sharing the classic pathological hallmark. From a systems-biology perspective, PD is a group of disorders that, while related by sharing the feature of nigral dopamine-neuron degeneration, exhibit unique genetic, biological, and molecular abnormalities, which probably respond differentially to a given therapeutic approach, particularly for strategies aimed at neuroprotection. Under this model, only biomarker-defined, homogenous subtypes of PD are likely to respond optimally to therapies proven to affect the biological processes within each subtype. Therefore, we suggest that precision medicine applied to PD requires a reevaluation of the biomarker-discovery effort. This effort is currently centered on correlating biological measures to clinical features of PD and on identifying factors that predict whether various prodromal states will convert into the classical movement disorder. We suggest, instead, that subtyping of PD requires the reverse view, where abnormal biological signals (i.e., biomarkers), rather than clinical definitions, are used to define disease phenotypes. Successful development of disease-modifying strategies will depend on how relevant the specific biological processes addressed by an intervention are to the pathogenetic mechanisms in the subgroup of targeted patients. This precision-medicine approach will likely yield smaller, but well-defined, subsets of PD amenable to successful neuroprotection. © 2017 International Parkinson and Movement Disorder Society., (© 2017 International Parkinson and Movement Disorder Society.)

Background/aims: The clinical diagnosis of degenerative forms of parkinsonism is imperfect, with past studies reporting a high rate of misdiagnosis by neurologists and movement disorder specialists, particularly early in the disease course. 123I-ioflupane SPECT (DaTscan) is a diagnostic neuroimaging tool used to distinguish essential tremor from tremor due to degenerative parkinsonisms. The present study expands upon prior studies of the clinical impact of DaTscan imaging in movement disorder centers by assessing quantitative estimates of diagnostic certainty, the impact on subsequent clinical decisions, and the degree to which the asymmetry in the results corresponds to laterality by clinical history and examination., Methods: In a prospective, observational study of the impact of DaTscan imaging in a movement disorder center over the course of 18 months, 4 specialists completed a questionnaire at the time they ordered imaging and again within 1 month after imaging., Results: Twenty-seven patients underwent DaTscan imaging; the result was normal in 4 cases (14.8%), abnormal in 22 cases (81.4%), and equivocal in 1 case (3.7%). In all cases of a normal result, the post-scan-predicted chance of degenerative parkinsonism decreased compared to the pre-scan prediction (p < 0.05), and in all cases of abnormal scan, the post-scan chance of degenerative parkinsonism increased or remained high (p < 0.0001). Clinical impacts were observed following imaging in a total of 24 patients (88.9%), including changes in medications for 18 patients and psychological impacts for 11 patients. Asymmetric clinical symptoms were corroborated based on the expected asymmetry of dopamine uptake deficits in 57.1% of the cases, were not present in 23.8%, and were opposite of expectations in 19.0% of the scans., Conclusion: DaTscan imaging results have an impact on physician's confidence in the diagnosis of parkinsonism and may also have a psychological impact on patients. DaTscan imaging may be a useful adjunct to clinical history and examination in selected patients., (© 2016 S. Karger AG, Basel.)

Objective: To assess whether multifocal, high-frequency repetitive transcranial magnetic stimulation (rTMS) of motor and prefrontal cortex benefits motor and mood symptoms in patients with Parkinson disease (PD)., Methods: Patients with PD and depression were enrolled in this multicenter, double-blind, sham-controlled, parallel-group study of real or realistic (electric) sham rTMS. Patients were randomized to 1 of 4 groups: bilateral M1 ( + sham dorsolateral prefrontal cortex [DLPFC]), DLPFC ( + sham M1), M1 + DLPFC, or double sham. The TMS course consisted of 10 daily sessions of 2,000 stimuli for the left DLPFC and 1,000 stimuli for each M1 (50 × 4-second trains of 40 stimuli at 10 Hz). Patients were evaluated at baseline, at 1 week, and at 1, 3, and 6 months after treatment. Primary endpoints were changes in motor function assessed with the Unified Parkinson's Disease Rating Scale-III and in mood with the Hamilton Depression Rating Scale at 1 month., Results: Of the 160 patients planned for recruitment, 85 were screened, 61 were randomized, and 50 completed all study visits. Real M1 rTMS resulted in greater improvement in motor function than sham at the primary endpoint (p < 0.05). There was no improvement in mood in the DLPFC group compared to the double-sham group, as well as no benefit to combining M1 and DLPFC stimulation for either motor or mood symptoms., Conclusions: In patients with PD with depression, M1 rTMS is an effective treatment of motor symptoms, while mood benefit after 2 weeks of DLPFC rTMS is not better than sham. Targeting both M1 and DLPFC in each rTMS session showed no evidence of synergistic effects., Clinicaltrialsgov Identifier: NCT01080794., Classification of Evidence: This study provides Class I evidence that in patients with PD with depression, M1 rTMS leads to improvement in motor function while DLPFC rTMS does not lead to improvement in depression compared to sham rTMS., (© 2016 American Academy of Neurology.)

Objective: An investigator-initiated, multicenter, randomized, placebo-controlled, double-blind clinical trial to determine whether coenzyme Q10 (CoQ10) is safe, well tolerated, and effective in slowing functional decline in progressive supranuclear palsy (PSP)., Methods: Sixty-one participants received CoQ10 (2,400 mg/d) or placebo for up to 12 months. Progressive Supranuclear Palsy Rating Scale (PSPRS), Unified Parkinson's Disease Rating Scale, activities of daily living, Mini-Mental State Examination, the 39-item Parkinson's Disease Questionnaire, and 36-item Short Form Health Survey were monitored at baseline and months 3, 6, 9, and 12. The safety profile of CoQ10 was determined by adverse events, vital signs, and clinical laboratory values. Primary outcome measures were changes in PSPRS and Unified Parkinson's Disease Rating Scale scores from baseline to month 12., Results: CoQ10 was well tolerated. No statistically significant differences were noted between CoQ10 and placebo groups in primary or secondary outcome measures. A nonsignificant difference toward slower clinical decline in the CoQ10 group was observed in total PSPRS among those participants who completed the trial. Before the final study visit at 12 months, 41% of participants withdrew because of travel distance, lack of perceived benefit, comorbidities, or caregiver issues., Conclusions: High doses of CoQ10 did not significantly improve PSP symptoms or disease progression. The high withdrawal rate emphasizes the difficulty of conducting clinical trials in patients with PSP., Clinicaltrialsgov Identifier: NCT00382824., Classification of Evidence: This study provides Class II evidence that CoQ10 does not significantly slow functional decline in PSP. The study lacks the precision to exclude a moderate benefit of CoQ10.

Introduction: The literature on the effect of head injuries on the risk of PD is inconclusive. Some researchers have hypothesized that studies that have seen an effect are simply capturing injury related to pre-clinical PD. However in animal models brain inflammation, which can be initiated by head trauma, has been shown to produce PD-like effects. Furthermore, animal studies have found that early life inflammation in particular is of relevance for PD pathology., Methods: We conducted an unmatched case-control study of 379 neurologist confirmed PD patients and 230 controls from the greater Boston, Massachusetts area with questionnaire data on history of head injury and other covariates. We used multivariable logistic regression to estimate adjusted odds ratios (OR) and their corresponding 95% confidence intervals (CI) for PD., Results: When we excluded injuries that occurred less than 10 years prior to the diagnosis of PD (in order to avoid reverse causation), we found an increased risk of PD associated with a head injury that resulted in a loss of consciousness, but it did not reach statistical significance (OR = 1.57; 95% CI = 0.89-2.80). We found a significant (p = 0.04) effect of age at first head injury. For every 5 year earlier age at first head injury with loss of consciousness the OR for PD was 1.37 (95% CI: 1.01-1.86)., Conclusion: Our results suggest that head injury in early life increases the risk of PD., (Copyright © 2015. Published by Elsevier Ltd.)