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Parkinson's disease (PD) is an incurable, progressive and common movement disorder that is increasing in incidence globally because of population aging. We hypothesized that the landscape of rare, protein-altering variants could provide further insights into disease pathogenesis. Here we performed whole-exome sequencing followed by gene-based tests on 4,298 PD cases and 5,512 controls of Asian ancestry. We showed that GBA1 and SMPD1 were significantly associated with PD risk, with replication in a further 5,585 PD cases and 5,642 controls. We further refined variant classification using in vitro assays and showed that SMPD1 variants with reduced enzymatic activity display the strongest association (<44% activity, odds ratio (OR) = 2.24, P = 1.25 × 10 -15 ) with PD risk. Moreover, 80.5% of SMPD1 carriers harbored the Asian-specific p.Pro332Arg variant (OR = 2.16; P = 4.47 × 10 -8 ). Our findings highlight the utility of performing exome sequencing in diverse ancestry groups to identify rare protein-altering variants in genes previously unassociated with disease., Competing Interests: Competing interests: Z.G.-O. received consultancy fees from Lysosomal Therapeutics, Idorsia, Prevail Therapeutics, Ono Therapeutics, Denali, Handl Therapeutics, Neuron23, Bial Biotech, Bial, UCB, Capsida, Vanqua Bio, Congruence Therapeutics, Takeda, Jazz Pharmaceuticals, Guidepoint, Lighthouse and Deerfield. R.N.A. received consultation fees from Biogen, Biohaven, Capsida, Gain Therapeutics, Genzyme/Sanofi, Janssen, Servier, SK Biopharmaceuticals, Takeda and Vanqua Bio. Y.X. holds a stock option in NeoCytogen Therapeutics where she is scientific co-founder and Chief Scientific Officer. M.A.N.’s participation in this project was part of a competitive contract awarded to DataTecnica, LLC by the National Institutes of Health to support open science research. M.A.N. also owns stock in Character Bio, Inc. and Neuron23, Inc. The other authors declare no competing interests., (© 2024. The Author(s).)

Cognitive impairment is a common but poorly understood non-motor aspect of Parkinson's disease, negatively affecting patient's functional capacity and quality of life. The mechanisms underlying cognitive impairment in Parkinson's disease are still elusive, limiting treatment and prevention strategies. This study investigates the molecular and cellular basis of cognitive impairment associated with heterozygous mutations in GBA1, the strongest risk gene for Parkinson's disease that encodes glucocerebrosidase (GCase), a lysosome enzyme that degrades the glycosphingolipid glucosylceramide into glucose and ceramide. Using a Gba1L444P/+ mouse model, we provide evidence that L444P heterozygous Gba1 mutation (L444P/+) causes hippocampus-dependent spatial and reference memory deficits independently of α-synuclein (αSyn) accumulation, GCase lipid substrate accumulation, dopaminergic dysfunction and motor deficits. The mutation disrupts hippocampal synaptic plasticity and basal synaptic transmission by reducing the density of hippocampal CA3-CA1 synapses, a mechanism that is dissociated from αSyn-mediated presynaptic neurotransmitter release. Using a well-characterized Thy1-αSyn pre-manifest Parkinson's disease mouse model overexpressing wild type human αSyn, we find that the L444P/+ mutation exacerbates hippocampal synaptic αSyn accumulation, synaptic and cognitive impairment in young Gba1L444P/+:Thy1-αSyn double mutant animals. With age, Thy1-αSyn mice manifest motor symptoms, and the double mutant mice exhibit more exacerbated synaptic and motor impairment than the Thy1-αSyn mice. Taken together, our results suggest that heterozygous L444P GBA1 mutation alone perturbs hippocampal synaptic structure and function, imposing a subclinical pathological burden for cognitive impairment. When co-existing αSyn overexpression is present, heterozygous L444P GBA1 mutation interacts with αSyn pathology to accelerate Parkinson's disease-related cognitive impairment and motor symptoms., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Purpose: Respiratory-swallow coordination (RSC) frequently changes in people with Parkinson's disease (PwPD). Little is known about how these changes relate to impairments in swallowing safety (penetration and aspiration) and efficiency (pharyngeal residue). Therefore, the aims of this study were to assess the relationships between RSC, pharyngeal residue, penetration, and aspiration in PwPD., Method: Twenty-four PwPD were recruited to undergo simultaneous assessment of RSC, swallowing safety, and swallowing efficiency. RSC was assessed using respiratory inductive plethysmography and nasal airflow and included measurements of respiratory pause duration, respiratory phase patterning, and lung volume during swallowing. Swallowing safety and efficiency were assessed using flexible endoscopic evaluation of swallowing, analyzed using the Visual Analysis of Swallowing Efficiency and Safety, and included measurements of pharyngeal residue, penetration, and aspiration. All data were blindly analyzed, with 20% of the data repeated for interrater reliability assessment. Multilevel statistical models were used to examine the relationships between RSC and swallowing., Results: A total of 812 swallows were analyzed from 24 participants. Only 33.4% of swallows exhibited the typical exhale-swallow-exhale pattern. Additionally, 95% of participants exhibited abnormal swallow function. More severe hypopharyngeal residue ratings were associated with inhaling before the swallow compared to exhaling before the swallow. Additionally, more severe events of penetration and aspiration were associated with (a) inhaling before the swallow compared to exhaling before the swallow, (b) inhaling after the swallow compared to exhaling after the swallow, and (c) longer swallow-related respiratory pause durations. Inhaling after the swallow exhibited the strongest relationship with impairments in swallowing safety when compared to all other RSC variables., Conclusions: RSC exhibited significant relationships with pharyngeal residue, penetration, and aspiration in these PwPD. Clinicians should attend to RSC when assessing swallowing in PwPD. Future research is needed to examine if training an exhale-swallow-exhale pattern can be used to improve disordered swallowing in PwPD., Open Science Form: https://doi.org/10.23641/asha.27211770.

Background: Patients with type 1 Gaucher disease (GD1) have a significantly increased risk of developing Parkinson's disease (PD)., Objective: The objective of this study was to evaluate skin α-synuclein (αSyn) seeding activity as a biomarker for GD1-related PD (GD1-PD)., Methods: This single-center study administered motor and cognitive examinations and questionnaires of nonmotor symptoms to adult patients with GD1. Optional skin biopsy was performed for skin αSyn seed amplification assay (αSyn SAA) using real-time quaking-induced conversion assay., Results: Forty-nine patients were enrolled, and 36 underwent skin biopsy. Two study participants had PD. Ten participants were αSyn SAA positive (27.8%), 7 (19.4%) were intermediate, and 19 (52.8%) were negative. Positive αSyn seeding activity was observed in the single GD1-PD case who consented to biopsy. αSyn SAA positivity was associated with older age (p = 0.043), although αSyn SAA positivity was more prevalent in patients with GD1 than historic controls., Conclusions: Longitudinal follow-up is required to determine whether skin αSyn seeding activity can be an early biomarker for GD1-PD. © 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.)

Previous studies have established that rare biallelic SYNJ1 mutations cause autosomal recessive parkinsonism and Parkinson's disease (PD). We analyzed 8165 PD cases, 818 early-onset-PD (EOPD, < 50 years) and 70,363 controls. Burden meta-analysis revealed an association between rare nonsynonymous variants and variants with high Combined Annotation-Dependent Depletion score (> 20) in the Sac1 SYNJ1 domain and PD (Pfdr = 0.040). A meta-analysis of EOPD patients demonstrated an association between all rare heterozygous SYNJ1 variants and PD (Pfdr = 0.029)., (© 2024. The Author(s).)

Genetic testing for Parkinson's disease (PD) is infrequently performed due to perceptions of low utility. We investigated the personal utility in PD GENEration and how results lead to enrollment in additional research studies. Participants (n = 972) underwent genetic testing, results disclosure, genetic counseling, and completed a survey examining the perceived personal utility of their results and interest in participating in additional studies. Most participants found their genetic test results useful, including satisfying curiosity (81%), feeling good about helping the medical community (80%), and having information to share with family (77%). There were no significant differences in responses based on result type. Forty-five percent of participants expressed interest in participating in research studies; whereas 16% of participants confirmed enrollment. Our results suggest that participants find personal utility in genetic testing regardless of results. Although participants may be interested in enrolling in additional research, they may need support and resources., (© 2024. The Author(s).)

Human microglia play a pivotal role in neurological diseases, but we still have an incomplete understanding of microglial heterogeneity, which limits the development of targeted therapies directly modulating their state or function. Here, we use single-cell RNA sequencing to profile 215,680 live human microglia from 74 donors across diverse neurological diseases and CNS regions. We observe a central divide between oxidative and heterocyclic metabolism and identify microglial subsets associated with antigen presentation, motility and proliferation. Specific subsets are enriched in susceptibility genes for neurodegenerative diseases or the disease-associated microglial signature. We validate subtypes in situ with an RNAscope-immunofluorescence pipeline and high-dimensional MERFISH. We also leverage our dataset as a classification resource, finding that induced pluripotent stem cell model systems capture substantial in vivo heterogeneity. Finally, we identify and validate compounds that recapitulate certain subtypes in vitro, including camptothecin, which downregulates the signature of disease-enriched subtypes and upregulates a signature previously associated with Alzheimer's disease., (© 2024. The Author(s), under exclusive licence to Springer Nature America, Inc.)

Background: Advanced Parkinson's disease (PD) can be treated with Levodopa-Carbidopa Intestinal Gel (LCIG)., Objective: To compare descriptive data of LCIG treatment in GBA1-PD and LRRK2-PD., Methods: This multicenter retrospective study compared clinical data obtained from electronic medical records of PD patients treated with LCIG. Patients were grouped based on their genetic status., Results: Fifty-two iPD, 15 LRRK2-PD and 23 GBA1-PD were included in this study. No difference in daily dose of LCIG or levodopa equivalent daily dose were detected. GBA1-PD had significantly shorter disease duration at LCIG initiation (p = 0.01) and experienced more hallucinations (p = 0.03) compared with LRRK2-PD and iPD. LRRK2-PD and iPD had significantly longer duration of LCIG treatment compared with GBA1-PD (p < 0.01)., Conclusion: Overall, LCIG treatment was well tolerated in LRRK2-PD and GBA1-PD. GBA1-PD required LCIG earlier in their course of their disease and had higher frequencies of hallucinations during treatment, attesting to a more severe disease course., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

GBA1 variants and decreased glucocerebrosidase (GCase) activity are implicated in Parkinson's disease (PD). We investigated the hypothesis that increased levels of glucosylceramide (GlcCer), one of GCase main substrates, are involved in PD pathogenesis. Using multiple genetic methods, we show that ATP10D, not GBA1 , is the main regulator of plasma GlcCer levels, yet it is not involved in PD pathogenesis. Plasma GlcCer levels were associated with PD, but not in a causative manner, and are not predictive of disease status. These results argue against targeting GlcCer in GBA1 -PD and underscore the need to explore alternative mechanisms and biomarkers for PD., Competing Interests: Potential Conflicts of Interest A.J., C.B., R.S., G.B., K.K.K., M.I.I., and P.B are current or previous employees of CENTOGENE GmbH, which is investigating the role of GlcCer in PD for investigational therapy development. H.I. and M.T.’s participation in this project was part of a competitive contract awarded to Data Tecnica LLC by the National Institutes of Health to support open science research. Z.G.O received consultancy fees from Lysosomal Therapeutics Inc. (LTI), Idorsia, Prevail Therapeutics, Ono Therapeutics, Denali, Handl Therapeutics, Neuron23, Bial Biotech, Bial, UCB, Capsida, Vanqua bio, Congruence Therapeutics, Takeda, Jazz Guidepoint, Lighthouse and Deerfield for development of GBA1-related therapeutics.

Glucocerebrosidase (GBA1) variants constitute numerically the most common known genetic risk factor for Parkinson's disease (PD) and are distributed worldwide. Access to GBA1 genotyping varies across the world and even regionally within countries. Guidelines for GBA1 variant counseling are evolving. We review the current knowledge of the link between GBA1 and PD, and discuss the practicalities of GBA1 testing. Lastly, we provide a consensus for an approach to counseling people with GBA1 variants, notably the communication of PD risk. © 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.)

Background and Objectives: It is widely cited that dementia occurs in up to 80% of patients with Parkinson disease (PD), but studies reporting such high rates were published over two decades ago, had relatively small samples, and had other limitations. We aimed to determine long-term dementia risk in PD using data from two large, ongoing, prospective, observational studies., Methods: Participants from the Parkinson's Progression Markers Initiative (PPMI), a multisite international study, and a long-standing PD research cohort at the University of Pennsylvania (Penn), a single site study at a tertiary movement disorders center, were recruited. PPMI enrolled de novo, untreated PD participants and Penn a convenience cohort from a large clinical center. For PPMI, a cognitive battery is administered annually, and a site investigator makes a cognitive diagnosis. At Penn, a comprehensive cognitive battery is administered either annually or biennially, and a cognitive diagnosis is made by expert consensus. Interval-censored survival curves were fit for time from PD diagnosis to stable dementia diagnosis for each cohort, using cognitive diagnosis of dementia as the primary end point and Montreal Cognitive Assessment (MoCA) score <21 and Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) Part I cognition score ≥3 as secondary end points for PPMI. In addition, estimated dementia probability by PD disease duration was tabulated for each study and end point., Results: For the PPMI cohort, 417 participants with PD (mean age 61.6 years, 65% male) were followed, with an estimated probability of dementia at year 10 disease duration of 9% (site investigator diagnosis), 15% (MoCA), or 12% (MDS-UPDRS Part I cognition). For the Penn cohort, 389 participants with PD (mean age 69.3 years, 67% male) were followed, with 184 participants (47% of cohort) eventually diagnosed with dementia. The interval-censored curve for the Penn cohort had a median time to dementia of 15 years (95% CI 13-15); the estimated probability of dementia was 27% at 10 years of disease duration, 50% at 15 years, and 74% at 20 years., Discussion: Results from two large, prospective studies suggest that dementia in PD occurs less frequently, or later in the disease course, than previous research studies have reported.

Alpha-synuclein (aSyn) aggregates in the central nervous system are the main pathological hallmark of Parkinson's disease (PD). ASyn aggregates have also been detected in many peripheral tissues, including the skin, thus providing a novel and accessible target tissue for the detection of PD pathology. Still, a well-established validated quantitative biomarker for early diagnosis of PD that also allows for tracking of disease progression remains lacking. The main goal of this research was to characterize aSyn aggregates in skin biopsies as a comparative and quantitative measure for PD pathology. Using direct stochastic optical reconstruction microscopy ( d STORM) and computational tools, we imaged total and phosphorylated-aSyn at the single molecule level in sweat glands and nerve bundles of skin biopsies from healthy controls (HCs) and PD patients. We developed a user-friendly analysis platform that offers a comprehensive toolkit for researchers that combines analysis algorithms and applies a series of cluster analysis algorithms (i.e., DBSCAN and FOCAL) onto d STORM images. Using this platform, we found a significant decrease in the ratio of the numbers of neuronal marker molecules to phosphorylated-aSyn molecules, suggesting the existence of damaged nerve cells in fibers highly enriched with phosphorylated-aSyn molecules. Furthermore, our analysis found a higher number of aSyn aggregates in PD subjects than in HC subjects, with differences in aggregate size, density, and number of molecules per aggregate. On average, aSyn aggregate radii ranged between 40 and 200 nm and presented an average density of 0.001-0.1 molecules/nm 2 . Our d STORM analysis thus highlights the potential of our platform for identifying quantitative characteristics of aSyn distribution in skin biopsies not previously described for PD patients while offering valuable insight into PD pathology by elucidating patient aSyn aggregation status., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2024 Sade, Fischel, Barak-Broner, Halevi, Gottfried, Bar-On, Sachs, Mirelman, Thaler, Gour, Kestenbaum, Gana Weisz, Anis, Soto, Roitman, Shahar, Doppler, Sauer, Giladi, Lev, Alcalay, Hassin-Baer, and Ashery.)

Background: Glucocerebrosidase 1 (GBA1) mutations are associated with reduced survival in Parkinson's disease but their effect on survival in dementia with Lewy bodies (DLB) is unclear., Objective: To assess the impact of GBA1 mutations on survival among Ashkenazi Jews with DLB, while controlling for APOE status., Methods: One hundred and forty participants from Tel Aviv Medical Center, Israel were genotyped for GBA1 mutations and APOE polymorphisms. Survival rates and follow-up cognitive screening scores were analyzed., Results: GBA1 mutation carriers had a two-fold increased risk of death (HR = 1.999), while APOE status did not independently affect survival. In a subset of patients with available clinical data (N = 63), carriers of the APOE ε4 allele showed faster cognitive deterioration, while GBA1 mutation carriers also declined more rapidly albeit not significantly., Conclusion: Understanding the genetic effects on survival and progression is crucial for patient counseling and inclusion in clinical trials. © 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.)

Variants in seven genes (LRRK2, GBA1, PRKN, SNCA, PINK1, PARK7 and VPS35) have been formally adjudicated as causal contributors to Parkinson's disease; however, individuals with Parkinson's disease are often unaware of their genetic status since clinical testing is infrequently offered. As a result, genetic information is not incorporated into clinical care, and variant-targeted precision medicine trials struggle to enrol people with Parkinson's disease. Understanding the yield of genetic testing using an established gene panel in a large, geographically diverse North American population would help patients, clinicians, clinical researchers, laboratories and insurers better understand the importance of genetics in approaching Parkinson's disease. PD GENEration is an ongoing multi-centre, observational study (NCT04057794, NCT04994015) offering genetic testing with results disclosure and genetic counselling to those in the US (including Puerto Rico), Canada and the Dominican Republic, through local clinical sites or remotely through self-enrolment. DNA samples are analysed by next-generation sequencing including deletion/duplication analysis (Fulgent Genetics) with targeted testing of seven major Parkinson's disease-related genes. Variants classified as pathogenic/likely pathogenic/risk variants are disclosed to all tested participants by either neurologists or genetic counsellors. Demographic and clinical features are collected at baseline visits. Between September 2019 and June 2023, the study enrolled 10 510 participants across >85 centres, with 8301 having received results. Participants were: 59% male; 86% White, 2% Asian, 4% Black/African American, 9% Hispanic/Latino; mean age 67.4 ± 10.8 years. Reportable genetic variants were observed in 13% of all participants, including 18% of participants with one or more 'high risk factors' for a genetic aetiology: early onset (<50 years), high-risk ancestry (Ashkenazi Jewish/Basque/North African Berber), an affected first-degree relative; and, importantly, in 9.1% of people with none of these risk factors. Reportable variants in GBA1 were identified in 7.7% of all participants; 2.4% in LRRK2; 2.1% in PRKN; 0.1% in SNCA; and 0.2% in PINK1, PARK7 or VPS35 combined. Variants in more than one of the seven genes were identified in 0.4% of participants. Approximately 13% of study participants had a reportable genetic variant, with a 9% yield in people with no high-risk factors. This supports the promotion of universal access to genetic testing for Parkinson's disease, as well as therapeutic trials for GBA1 and LRRK2-related Parkinson's disease., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Guarantors of Brain.)

Background: Among LRRK2-associated parkinsonism cases with nigral degeneration, over two-thirds demonstrate evidence of pathologic alpha-synuclein, but many do not. Understanding the clinical phenotype and underlying biology in such individuals is critical for therapeutic development. Our objective was to compare clinical and biomarker features, and rate of progression over 4 years follow-up, among LRRK2-associated parkinsonism cases with and without in vivo evidence of alpha-synuclein aggregates., Methods: Data were from the Parkinson's Progression Markers Initiative, a multicenter prospective cohort study. The sample included individuals diagnosed with Parkinson disease with pathogenic variants in LRRK2. Presence of CSF alpha-synuclein aggregation was assessed with seed amplification assay. A range of clinician- and patient- reported outcome assessments were administered. Biomarkers included dopamine transporter SPECT scan, CSF amyloid-beta 1-42 , total tau, phospho-tau 181 , urine bis(monoacylglycerol)phosphate levels, and serum neurofilament light chain. Linear mixed effects models examined differences in trajectory in CSF negative and positive groups., Results: 148 LRRK2-parkinsonism cases (86% with G2019S variant), 46 negative and 102 positive for CSF alpha-synuclein seed amplification assay were included. At baseline, the negative group were older than the positive group (median [interquartile range] 69.1 [65.2-72.3] vs 61.5 [55.6-66.9] years, p<0.001) and a greater proportion were female (28 (61%) vs 43 (42%), p=0.035). Despite being older, the negative group had similar duration since diagnosis, and similar motor rating scale (16 [11-23] vs 16 [10-22], p=0.480) though lower levodopa equivalents. Only 13 (29%) of the negative group were hyposmic, compared to 75 (77%) of the positive group. Lowest putamen dopamine transporter binding expected for age and sex was greater in the negative vs positive groups (0.36 [0.29-0.45] vs 0.26 [0.22-0.37], p<0.001). Serum neurofilament light chain was higher in the negative group compared to the positive group (17.10 [13.60-22.10] vs 10.50 [8.43-14.70]; age-adjusted p-value=0.013). In terms of longitudinal change, the negative group remained stable in functional rating scale score in contrast to the positive group who had a significant increase (worsening) of 0.729 per year (p=0.037), but no other differences in trajectory were found., Conclusion: Among individuals diagnosed with Parkinson disease with pathogenic variants in the LRRK2 gene, we found clinical and biomarker differences in cases without versus with in vivo evidence of CSF alpha-synuclein aggregates. LRRK2 parkinsonism cases without evidence of alpha-synuclein aggregates as a group exhibit less severe motor manifestations and decline may have more significant cognitive dysfunction. The underlying biology in LRRK2-parkinsonism cases without evidence of alpha-synuclein aggregates requires further investigation., Competing Interests: Competing interests The authors report no competing interests.

Multiple system atrophy (MSA) is an adult-onset, sporadic synucleinopathy characterized by parkinsonism, cerebellar ataxia, and dysautonomia. The genetic architecture of MSA is poorly understood, and treatments are limited to supportive measures. Here, we performed a comprehensive analysis of whole genome sequence data from 888 European-ancestry MSA cases and 7,128 controls to systematically investigate the genetic underpinnings of this understudied neurodegenerative disease. We identified four significantly associated risk loci using a genome-wide association study approach. Transcriptome-wide association analyses prioritized USP38-DT, KCTD7, and lnc-KCTD7-2 as novel susceptibility genes for MSA within these loci, and single-nucleus RNA sequence analysis found that the associated variants acted as cis-expression quantitative trait loci for multiple genes across neuronal and glial cell types. In conclusion, this study highlights the role of genetic determinants in the pathogenesis of MSA, and the publicly available data from this study represent a valuable resource for investigating synucleinopathies., Competing Interests: Declaration of interests T.G.B. is a consultant for Aprinoia Therapeutics, Vivid Genomics, and Avid Radiopharmaceutical and is a scientific advisory board member for Vivid Genomics. J.A.H., H.R.M., B.J.T., and H.R.M. hold US, EU, and Canadian patents on the clinical testing and therapeutic intervention for the hexanucleotide repeat expansion of C9orf72. B.J.T. and S.W.S. receive research support from Cerevel Therapeutics. B.J.T. is an editorial and advisory board member for Brain, eClinicalMedicine, Journal of Neurology, Neurosurgery, and Psychiatry, and Neurobiology of Aging. H.R.M. reports paid consultancy from Biogen, Biohaven, Lundbeck, UCB, and Denali as well as lecture fees and honoraria from the Wellcome Trust and the Movement Disorders Society. H.R.M. received research grants from Parkinson’s UK, Cure Parkinson’s Trust, PSP Association, CBD Solutions, the Drake Foundation, and the Medical Research Council. H.K. is editor-in-chief of Clinical Autonomic Research, serves as principal investigator (PI) of a clinical trial sponsored by Biogen MA Inc. (TRACK MSA, S19-01846), and received consultancy fees from Lilly USA LLC, Biohaven Pharmaceuticals Inc., Takeda Pharmaceutical Company Ltd., Ono Pharma UK Ltd., Lundbeck LLC, and Theravance Biopharma US Inc. A.F. reports royalties from Springer Verlag; speaker fees and honoraria from Theravance Biopharma, GE Health Care, Broadview Ventures, Austrian Autonomic Society, Stopp-HSP, and Elsevier; and research grants from the FWF-Austrian Science Fund, Medical University of Innsbruck, US MSA Coalition, Dr. Johannes and Hertha Tuba Foundation, and Austrian Exchange Program, outside of the present work. J.-A.P. is an editorial board member of Movement Disorders, Parkinsonism & Related Disorders, BMC Neurology, and Clinical Autonomic Research. I.B. received consultancy fees from Theravance Biopharma US Inc., Amenal Pharmaceutics, Regeneron Pharmaceuticals, Takeda Pharmaceuticals, and Neurawell Therapeutics. S.W.S. serves on the scientific advisory board of the Lewy Body Dementia Association and the Multiple System Atrophy Coalition. S.W.S. is an editorial board member for the Journal of Parkinson’s Disease and JAMA Neurology. A.P. serves on the board of directors for CurePSP, has received research grants from the National Institutes of Health and the Michael J. Fox Foundation, and has received consultancy fees from AbbVie Inc., Biogen Inc., SciNeuro Pharmaceuticals, Ono Pharma, and Ferrer Internacional, S.A. A.T. serves on the scientific advisory board for Vivid Genomics. R.H.R. is currently employed by CoSyne Therapeutics; all work performed for this publication was performed on her own time and not as a part of her duties as an employee. Z.K.W. is partially supported by the NIH/NIA and NIH/NINDS (1U19AG063911, FAIN: U19AG063911), the Mayo Clinic Center for Regenerative Medicine, the gifts from the Donald G. and Jodi P. Heeringa Family, the Haworth Family Professorship in Neurodegenerative Diseases fund, and the Albertson Parkinson's Research Foundation. He serves as PI or co-PI on Biohaven Pharmaceuticals Inc. (BHV4157-206) and Vigil Neuroscience Inc. (VGL101-01.002, VGL101-01.201, PET tracer development protocol, Csf1r biomarker and repository project, and ultra-high field MRI in the diagnosis and management of CSF1R-related adult-onset leukoencephalopathy with axonal spheroids and pigmented glia) projects/grants. He serves as co-PI of the Mayo Clinic APDA Center for Advanced Research, as an external advisory board member for Vigil Neuroscience Inc., and as a consultant on neurodegenerative medical research for Eli Lilli & Company. F.K. received personal fees from Institut de Recherches Internationales Servier, Takeda Pharmaceuticals, Sanofi, Teva, Vial, and the Austrian Society of Neurology in the past 12 months, and he has ongoing grant support from the Austrian Science Fund (FWF) and the National Institutes of Health outside of the submitted work. W.G.M. has received fees for editorial activities with Elsevier and has served as an advisor for Lundbeck, Biohaven, Roche, Alterity, Servier, Inhibikase, Takeda, and Teva., (Published by Elsevier Inc.)

One of the most common genetic risk factors for Parkinson's disease (PD) are variants in GBA1 , which encodes the lysosomal enzyme glucocerebrosidase (GCase). GCase deficiency has been associated with an increased PD risk, but not all individuals with low GCase activity are carriers of GBA1 mutations, suggesting other factors may be acting as modifiers. We aimed to discover common variants associated with GCase activity, as well as replicate previously reported associations, by performing a genome-wide association study using two independent cohorts: a Columbia University cohort consisting of 697 PD cases and 347 controls and the Parkinson's Progression Markers Initiative (PPMI) cohort consisting of 357 PD cases and 163 controls. As expected, GBA1 variants have the strongest association with decreased activity, led by p.N370S (beta = -4.36, se = 0.32, p = 5.05e-43). We also identify a novel association in the GAA locus (encoding for acid alpha-glucosidase, beta = -0.96, se = 0.17, p = 5.23e-09) that may be the result of an interaction between GCase and acid alpha-glucosidase based on various interaction analyses. Lastly, we show that several PD-risk loci are potentially associated with GCase activity. Further research will be needed to replicate and validate our findings and to uncover the functional connection between acid alpha-glucosidase and GCase., Competing Interests: 5.2Z.G.O received consultancy fees from Lysosomal Therapeutics Inc. (LTI), Idorsia, Prevail Therapeutics, Ono Therapeutics, Denali, Handl Therapeutics, Neuron23, Bial Biotech, Bial, UCB, Capsida, Vanqua bio, Congruence Therapeutics, Takeda, Jazz Guidepoint, Lighthouse and Deerfield.

Previous studies have suggested that rare biallelic SYNJ1 mutations may cause autosomal recessive parkinsonism and Parkinson's disease (PD). Our study explored the impact of rare SYNJ1 variants in non-familial settings, including 8,165 PD cases, 818 early-onset PD (EOPD, <50 years) and 70,363 controls. Burden meta-analysis using optimized sequence Kernel association test (SKAT-O) revealed an association between rare nonsynonymous variants in the Sac1 SYNJ1 domain and PD (P fdr =0.040). Additionally, a meta-analysis focusing on patients with EOPD demonstrated an association between all rare SYNJ1 variants and PD (P fdr =0.029). Rare SYNJ1 variants may be associated with sporadic PD, and more specifically with EOPD., Competing Interests: Competing interests ZGO received consultancy fees from Lysosomal Therapeutics Inc. (LTI), Idorsia, Prevail Therapeutics, Ono Therapeutics, Denali, Handl Therapeutics, Neuron23, Bial Biotech, Bial, UCB, Capsida, Vanqua bio, Congruence Therapeutics, Takeda, Jazz Pharmaceuticals, Guidepoint, Lighthouse and Deerfield.

Background: Mild cognitive impairment (MCI) is common in Parkinson's disease (PD). We aimed to assess the incidence of MCI among patients with PD, carriers of mutations in LRRK2 and GBA1 genes, based on the movement disorder society (MDS) criteria for the diagnosis of MCI in early-stage PD., Methods: Patients with PD were included if they scored ≤2 on the Hoehn and Yahr and ≤6 years since motor symptom onset. A group of age and gender matched healthy adults served as controls. A neuropsychological cognitive battery was used covering five cognitive domains (executive functions, working memory, memory, visuospatial and language). MCI was explored while applying two methods (level I and II). Frequency of MCI was assessed in comparison between groups., Results: 70 patients with idiopathic PD (iPD) (68 % males), 42 patients with LRRK2-PD (61 % males), 83 patients with GBA1-PD (63 % males) and 132 age and gender matched controls (61 % males), participated in this study. PD groups were similar in clinical characteristics. Level I criteria were positive in 57.5 % of iPD, 43 % of LRRK2-PD and 63.4 % of the GBA1-PD (p = 0.071). Level II criteria was met by 39 % of iPD, 14 % LRRK2-PD and 41 % of GBA1-PD (p < 0.001), when using a 2 standard-deviation (SD) threshold. GBA1-PD and iPD showed impairments on multiple domains even in the more conservative 2 SD, reflecting MCI., Conclusions: The majority of our PD cohort was classified as MCI when assessed with strict criteria. GBA1-PD and iPD showed a more widespread pattern of MCI compared with LRRK2-PD., Competing Interests: Declaration of competing interest AT – Receiving research grants from MJFF, honoraria from AbbVie and consulting fees from Capsida. VL – nothing to report. ER – nothing to report. NO – nothing to report. AS – nothing to report. BC – nothing to report. NG – Received research grant support from The Michael J Fox Foundation, The National Parkinson Foundation, The European Union and The Israel Science Foundation, Biogen and Ionis. Receives support from The Sieratzki Family Foundation and The Aufzien Academic Center in Tel-Aviv University. Serves as a consultant to Sionara, NeuroDerm and Pharma2B. JCS – Employee of Biogen and holds company stocks. JMC – Reports having equity positions in VanquaBio and Immunobrain Checkpoint. MGW – nothing to report. OG – nothing to report. AO – Research support from the Michael J Fox Foundation and Biogen. RNA – Received research grant support from the MJFF, the Parkisnon's Foundation and the Silverstein Foundation. Received consultation fees from Sanofi, Takeda, Capsida, and Gain Therapeutics. RNA institution (TLVMC) has received research funds from Biogen. AM – Received research grant support from MJFF, The department of defense (DOD), JPND and the Israeli Ministry of Health. Received honoraria from Abbvie and Biogen., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

There is an urgent need to identify drug targets for disease modification in Parkinson's Disease (PD). In this mini-review we highlight the reasons genetically-defined drug targets show great promise. Specifically, clinical trials targeting the glucocerebrosidase-1 (GBA1) and leucine-rich repeat kinase 2 (LRRK2) genes are underway. Two key knowledge gaps are 1. How should we modify the GBA1 and LRRK2 pathways? and 2. Which patient populations are most likely to benefit? The exact mechanisms by which mutations in these genes cause PD are not fully understood. Most drugs targeting the GBA1 pathway in clinical trials aim at increasing glucocerebrosidase enzymatic (GCase) activity and targeting the LRRK2 pathway, at reducing its kinase activity. Carriers of mutations in these genes are natural candidates for such interventions; however, there are some biomarker data, specifically for GBA1, to support studying such interventions in non-carriers, i.e., sporadic PD. In summary, we anticipate significant progress in our path towards precision medicine in PD in the coming years., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: ROY ALCALAY reports a relationship with Biogen Inc that includes: consulting or advisory. ROY ALCALAY reports a relationship with Sanofi that includes: consulting or advisory. ROY ALCALAY reports a relationship with Takeda Pharmaceutical Company Limited that includes: consulting or advisory. ROY ALCALAY reports a relationship with Biohaven Ltd that includes: consulting or advisory. ROY ALCALAY reports a relationship with Servier Monde that includes: consulting or advisory. ROY ALCALAY reports a relationship with Gain Therapeutics, Inc. that includes: consulting or advisory. ROY ALCALAY reports a relationship with Capsida Biotherapeutics that includes: consulting or advisory. GADI MAAYAN ESHED reports a relationship with Bionaut Labs that includes: consulting or advisory. ROY ALCALAY received consultation fees from Vanqua Bio., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Mounting data suggest an important role for the immune system in Parkinson's disease (PD). Previous evidence of increased natural killer (NK) cell populations in PD suggests a potential role of NK cells in the pathogenesis of the disease. Previous studies have analyzed NK cell populations using aggregation by variable expression of CD56 and CD16. It remains unknown what differences may exist between NK cell subpopulations when stratified using more nuanced classification. Here, we profile NK cell subpopulations and elucidate the expressions of activating, NKG2D, inhibitory, NKG2A, and homing, CX3CR1, receptors on NK cell subpopulations in PD and healthy controls (HC). We analyzed cryopreserved PMBC samples using a 10-color flow cytometry panel to evaluate NK cell subpopulations in 31 individuals with sporadic PD and 27 HC participants. Here we identified significant differences in the CD56 dim NK subset that changes with disease severity in PD. Furthermore, the expressions of NKG2D in all three NK cell subsets were significantly elevated in PD patients compared to HC. Notably, NKG2A expression in the CD56 bright NK subset increased in PD patients with longer disease duration but there were no changes in CX3CR1. In summary, our data suggests that changes in NK cells may be influenced by the clinical severity and duration of PD., (© 2024. The Author(s).)

Parkinson´s disease (PD) is a common neurodegenerative movement disorder and leucine-rich repeat kinase 2 (LRRK2) is a promising therapeutic target for disease intervention. However, the ability to stratify patients who will benefit from such treatment modalities based on shared etiology is critical for the success of disease-modifying therapies. Ciliary and centrosomal alterations are commonly associated with pathogenic LRRK2 kinase activity and can be detected in many cell types. We previously found centrosomal deficits in immortalized lymphocytes from G2019S-LRRK2 PD patients. Here, to investigate whether such deficits may serve as a potential blood biomarker for PD which is susceptible to LRKK2 inhibitor treatment, we characterized patient-derived cells from distinct PD cohorts. We report centrosomal alterations in peripheral cells from a subset of early-stage idiopathic PD patients which is mitigated by LRRK2 kinase inhibition, supporting a role for aberrant LRRK2 activity in idiopathic PD. Centrosomal defects are detected in R1441G-LRRK2 and G2019S-LRRK2 PD patients and in non-manifesting LRRK2 mutation carriers, indicating that they accumulate prior to a clinical PD diagnosis. They are present in immortalized cells as well as in primary lymphocytes from peripheral blood. These findings indicate that analysis of centrosomal defects as a blood-based patient stratification biomarker may help nominate idiopathic PD patients who will benefit from LRRK2-related therapeutics., (© 2024. The Author(s).)

Pregnancy in women with early-onset Parkinson's disease (PD) is likely to have a higher frequency given the trend toward increasing maternal age, thus resulting in a greater overlap time between childbearing age and PD risk. Deep brain stimulation (DBS) therapy is nowadays offered to PD patients at earlier stage of the disease, when women can still be pre-menopausal. However, few data are available about DBS safety during pregnancy. From a review of the available literature, only one article was published on this topic so far. Therefore, we have developed a clinical consensus on the safety of DBS during pregnancy in PD patients.

Introduction : MAPT locus is associated with Parkinson's disease (PD), which is located within a large inversion region of high linkage disequilibrium (LD). We aimed to determine whether the H2-haplotype protective effect and its effect size depends on the GBA1 or LRRK2 risk allele carrier status, and to further characterize genetic alterations that might contribute to its effect. Methods : LD analysis was performed using whole-genome sequencing data of 202 unrelated Ashkenazi Jewish (AJ) PDs. A haplotype-divergent variant was genotyped in a cohort of 1200 consecutively recruited AJ-PDs. The odd ratios were calculated using AJ-non-neuro cases from the gnomAD database as the controls in an un-stratified and a stratified manner according to the mutation carrier status, and the effect on the Age at Motor Symptom Onset (AMSO) was examined. Expression and splicing quantitative trait locus (eQTL and sQTL) analyses were carried out using brain tissues from a database. Results : The H2 haplotype exhibited significant association with PD protection, with a similar effect size in GBA1 carriers, LRRK2 -G2019S carriers, and non-carriers (OR = 0.77, 0.69, and 0.82, respectively), and there was no effect on AMSO. The LD interval was narrowed to approximately 1.2 Mb. The H2 haplotype carried potential variants in candidate genes ( MAPT and SPPL2C ); structural deletions and segmental duplication ( KANSL1 ); and variants affecting gene expression and intron excision ratio in brain tissues ( LRRC37A/2 ). Conclusions : Our results demonstrate that H2 is associated with PD and its protective effect is not influenced by the GBA1/LRRK2 risk allele carrier status. This effect may be genetically complex, resulting from different levels of variations such as missense mutations in relevant genes, structural variations, epigenetic modifications, and RNA expression changes, which may operate independently or in synergy.

We report here a retrospective case series of 3 MG patients suffering from difficulty opening eyes that appeared together with a diagnosis of MG. All are male patients with late-onset MG who are seropositive for anti-acetylcholine receptor antibodies. The phenomenon was characterized by difficulty opening the eyes after forced closure or reflex eye closure, improving with the ice pack test and with repeated forced eye closure but worsening with pyridostigmine treatment. We provide a detailed clinical, serological, imaging and electrophysiological examination of these patients. Electromyography evaluation did not show spontaneous muscle activity or myotonia at rest in the orbital part of the orbicularis oculi muscle. However, there was sustained muscle activity lasting several seconds in the pre-tarsal and pre-septal parts of this muscle. Videos of those reported symptoms were produced and provided. We discuss the possible neurological pathophysiology of this disorder and suggest to name this rare ocular disorder "myotonia-like disorder of the pre-tarsal and pre-septal parts of the orbicularis oculi". This study expands our knowledge of this rare clinical feature of MG and highlights the need for increased awareness of it and further investigation of this ocular manifestation., Competing Interests: Declaration of Competing Interest None., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Parkinson's disease (PD) is the fastest-growing neurodegenerative disorder, currently affecting ~7 million people worldwide. PD is clinically and genetically heterogeneous, with at least 10% of all cases explained by a monogenic cause or strong genetic risk factor. However, the vast majority of our present data on monogenic PD is based on the investigation of patients of European White ancestry, leaving a large knowledge gap on monogenic PD in underrepresented populations. Gene-targeted therapies are being developed at a fast pace and have started entering clinical trials. In light of these developments, building a global network of centers working on monogenic PD, fostering collaborative research, and establishing a clinical trial-ready cohort is imperative. Based on a systematic review of the English literature on monogenic PD and a successful team science approach, we have built up a network of 59 sites worldwide and have collected information on the availability of data, biomaterials, and facilities. To enable access to this resource and to foster collaboration across centers, as well as between academia and industry, we have developed an interactive map and online tool allowing for a quick overview of available resources, along with an option to filter for specific items of interest. This initiative is currently being merged with the Global Parkinson's Genetics Program (GP2), which will attract additional centers with a focus on underrepresented sites. This growing resource and tool will facilitate collaborative research and impact the development and testing of new therapies for monogenic and potentially for idiopathic PD patients., Competing Interests: I have read the journal’s policy and the authors of this manuscript have the following competing interests: Roy N. Alcalay received consulting fees from Avrobio, Caraway, Ono Therapeutics, GSK, Merck, Sanofi, Janssen and grants from the Michael J. Fox Foundation, DOD, the Parkinson’s Disease Foundation, and the NIH. Melinda Barkhuizen received a PhD scholarship from the National Research Foundation of South Africa (grant numbers 89230 and 98217) and internal funding from the research center where the study was conducted (DST/NWU Preclinical Drug Development Platform, North-West University, South Africa); Ampath Pathology laboratories in South Africa donated services in the form of drawing participant blood for DNA extractions, Several neurologists in South Africa assisted the authors with identifying patients with Parkinson`s disease and referring them to the genotyping study; the North-West University, South Africa provided Ethical oversight and approval of the genotyping project. Vincenzo Bonifati received grants from Stichting Parkinson Fonds (Netherlands) and Alzheimer Nederland, he received honoraria from the International Parkinson and Movement Disorder Society (MDS), for lectures and as Chair of the International Congress Scientific Program Committee (2020-2021), and from Elsevier Ltd. as co-Editor in Chief of the journal Parkinsonism & Related Disorders (2018-current); he is unpaid member of the Stichting Parkinson Fonds (Netherlands). Kathrin Brockmann received grants from the German Federal Ministry of Education and Research (BMBF; PDStrat; FKZ 031L0137B) and from the German Center for Neurodegenerative Diseases (DZNE), consulting fees from Abbvie, Lundbeck, UCB, Zambon, Roche, and honoraria from Abbvie and UCB. Jordi Clarimon is full-time employee at Lundbeck A/S (Denmark). Mario Cornejo-Olivas has subcontracts with Cleveland Clinic and San Marcos Foundation for recruiting participants for the LARGE PD study in Peru. Jean-Christophe Corvol received grants from Sanofi and the Michael J. Fox Foundation, consulting fees from Biogen, UCB, Denali, Idorsia, Prevail therapeutics, Theranexus, and honoraria from Biogen. Joana Damásio received honoraria from Zambon Pharmaceuticals. Anna De Rosa received grants for ROPAD – the Rostock International Parkinson’s Disease Study, sponsored by Centogene and grants from Zambon and AIFA (Italian Agency of Drug), and she is member of the advisory board at BIAL. Joaquim Ferreira received grants from Fundação MSD (Portugal), Novartis, Medtronic, and Abbvie, and lecture fees from Lundbeck, Abbvie, BIAL, Biogen, Sunovion Pharmaceuticals, ONO, Affiris, and Zambon, payment for expert testimony from Novartis, and he participates in advisory boards of Lundbeck, Abbvie, BIAL, Affiris, Sunovion Pharmaceuticals, and Zambon; he is employed by CNS (Campus Néurologico Sénior) and the Medical Faculty of Lisbon. Emilia Gatto received consulting fees from Bago Argentina, honoraria from Bago Argentina,UCB, IPMDS, and Europharm, and participates in advisory boards of Bago Argentina and UCB. Nir Giladi received grants from the Michael J Fox Foundation, The National Parkinson Foundation, The European Union, The Israel Science Foundation Teva, NNE program, Biogen, Ionis, Sieratzki Family Foundation, and The Aufzien Academic Center in Tel-Aviv University; he holds royalties or licenses at Lysosomal Therapeutics (LTI); he received consulting fees from Sionara, NeuroDerm, Pharma2B, Denali, Neuron23, Sanofi-Genzyme, Biogen, and Abbvie; he received honoraria from Abbvie, Sanofi-Genzyme, and the Movement Disorder Society. Nobutaka Hattori received grants from the Japan Society for the Promotion of Science (JSPS; 18H04043, 21H04820, 19K22603), the Japan Agency for Medical Research and Development (AMED; JP20dm0307101, JP20dm0207070, JP20ek0109358, JP19ek0109393, JP19gm0710011, JP19km0405206), Health Labour Sciences Research Grant (20FC1049, H29-FC1-062, H29-FC1-033), and the Japan Science and Technology Agency (JPMJMS2024-5); he participates in advisory boards at Dai-Nippon Sumitomo Pharma, Takeda Pharmaceutical, Kyowa Kirin, TEIJIN PHARMA LIMITED, Novartis Pharma, Ono Pharmaceutical, Biogen Idec Japan, and Kissei Pharmaceutical; he receives consulting fees from Hisamitsu Pharma; he received honoraria from Dai-Nippon Sumitomo Pharma, Takeda Pharmaceutical, Kyowa Kirin, AbbVie GK, Nippon Boehringer Ingelheim, Otsuka Pharmaceutical, Novartis Pharma, Bristol-Myers Squibb, Ono Pharmaceutical, FP Pharmaceutical, Eisai, Kissei Pharmaceutical, Nihon Medi-physics, and Daiichi Sankyo; he received payment for expert testimony from Mitsubishi Tanabe Pharma; he received support for attending meeting from Takeda Pharmaceutical, and Kyowa Kirin; he has 17 patents planned or pending and 5 issued; he is Team Leader at the Neurodegenerative Disorders Collaborative Laboratory, RIKEN Center for Brain Science; he holds equity stock (8%) of PARKINSON Laboratories Co. Ltd., unrelated to the submitted work. Silvia Jesús has received grants from “Consejería de Salud y Familias” PI-0459-2018, “acción B Clínicos-Investigdores” B-0007-2019 and from the “instituto de Salud Carlos III” PI-18/01898; she received honoraria from Abbvie, Bial, Merz, UCB, Italfarmaco, Zambon and Server. Valtteri Kaasinen received grants from Turku University Foundation, Päivikki and Sakari Sohlberg Foundation, and the Finnish Cultural Foundation; he received consulting fees from Nordic Infucare, Abbvie, and Adamant Health; he received honoraria from Nordic Infucare and Abbvie; he received Support for attending meetings and/or travel from Nordic Infucare; he participates on a Data Safety Monitoring Board or Advisory Board at Nordic Infucare and Abbvie; he is board member of the Finnish Neurological Society. Christine Klein received royalties from Oxford University Press; she received consulting fees from Centogene and Retromer Therapeutics; she received payment or honoraria from Desitin Pharma; she received support to attend meetings from the Movement Disorder Society; she participates on a Data Safety Monitoring Board or Advisory Board at the Else Kroener Fresenius Foundation. Peter Klivenyi received honoraria from Abbvie and Medtronic. Vladimir Kostic received Grant 17590 from the Ministry of Education, Science and Technological Development of Serbia; he received honoraria from Novartis and Boehringer Ingelheim. Shen-Yang Lim received the following grants, (i) Stipend - Global Parkinson’s Genetics Program (GP2) Working Group Co-Lead Award, from the Michael J. Fox Foundation, (ii) Michael J. Fox Foundation (Grant 18305: "Identifying leucocyte and urine biomarkers in PD patients with LRRK2 G2385R variant"). George Mellick received grants from the National Health and Medical Research Foundation, Australia (APP1151854, APP1084560). Lukasz Milanowski received grants from the Polish National Agency for Academic Exchange Iwanowska’s Fellowship PPN/IWA/2018/1/00006/U/00001/01, the APDA, the Foundation for Polish Science (FNP) and the Haworth Family Professorship in Neurodegenerative Diseases Fund. Pablo mir received grants from the Spanish Ministry of Science and Innovation (RTC2019-007150-1), the Instituto de Salud Carlos III-Fondo Europeo de Desarrollo Regional (ISCIII-FEDER, PI19/01576), and the Consejería de Salud y Bienestar Social de la Junta de Andalucía (PE-0210-2018); he received payment or honoraria for lectures from Abbvie, Abbott, and Zambon; he received Support for attending meetings and travel from Abbvie. Shalini Padmanabhan is employed by the Michael J. Fox Foundation. Andreas Puschmann received grants from Region Skåne, Sweden, Skåne University Hospital, Sweden, The Swedish Parkinson Academy, The Swedish Parkinson Foundation (Parkinsonfonden), MultiPark – a strategic research environment at Lund University, and Bundy Academy, Sweden; he received honoraria from Elsevier (Associate editor for Parkinsonism and Related Disorders), from the International Parkinson and Movement Disorder Society (MDS), and from the International Association of Parkinsonism and Related Disorders; he received support for travels from the International Association of Parkinsonism and Related Disorders; he is board member of the International Association of Parkinsonism and Related Disorders. Mariana Spitz received funding from Centogene for the ROPAD study; she received support for travels from Roche. Justin Solle is employed by the Michel J. Fox Foundation. Oksana Suchowersky received grants from Roche and WaveLifeSciences; she holds royalties or licenses at UpToDate; she received consulting fees from Abbvie and Sunovion; she received honoraria from the World Parkinson Conference; she participates in advisory boards at Alexion; she is board member of the Parkinson Society Alberta. Pichet Termsarasab received book royalties from Elsevier and Springer Nature Switzerland; he received honoraria for manuscript writing from MedLink Neurology and for lectures from Viatris. Bart van de Warrenburg received grants from Radboudumc, ZonMW, Hersenstichting, Gossweiler Foundation, and the Michael J Fox Foundation; he holds royalties or licenses at BSL Springer Nature; he received consulting fees from uniQure; he received honoraria from UKM Medical Center Kuala Lumpur; he participates in Medical advisory board of patient organizations (unpaid); he is unpaid member of Steering committees or executive boards of various research consortia; he received a wearable sensor set by Brugling Fund/Hersenstichting. Caroline H. Williams-Gray collaborates with Astra-Zeneca on the microbiome in Parkinson’s disease; she received consultancy fees from Modus Outcomes and Evidera, Inc./GlaxoSmithKline; she received honoraria from Profile Pharma Limited. Eva-Juliane Vollstedt, Harutyun Madoev, Anna Aasly, Azlina Ahmad-Annuar, Bashayer Al-Mubarak, Victoria Alvarez, Ignacio Amorin, Grazia Annesi, David Arkadir, Soraya Bardien, Roger A. Barker, A. Nazli Basak, Agnita Boon, Laura Brighina, Andrea Carmine Belin, Jonathan Carr, Leonor Correia Guedes, David Crosiers, Parimal Das, Patricia de Carvalho Aguiar, Jolanta Dorszewska, Sibel Ertan, Rosangela Ferese, Gençer Genç, Pilar Gómez-Garre, Hasmet Hanagasi, Faycal Hentati, Dorota Hoffman-Zacharska, Sergey N. Illarioshkin, Joseph Jankovic, Anneke Kievit, Dariusz Koziorowski, Andrea A. Kühn, Anthony E. Lang, Chin-Hsien Lin, Katja Lohmann, Vladana Markovic, Mika Henrik Martikainen, Marcelo Merello, Özgür Öztop-Çakmak, Márcia Mattos Gonçalves Pimentel, Teeratorn Pulkes, Ekaterina Rogaeva, Esther M. Sammler, Maria Skaalum Petersen, Matej Skorvanek, Ai Huey Tan, Avner Thaler, Vitor Tumas, Enza Maria Valente, Ruey-Mei Wu, Baorong Zhang, and Alexander Zimprich report no conflict of interest. This does not alter our adherence to PLOS ONE policies on sharing data and materials., (Copyright: © 2023 Vollstedt et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Background: Several lysosomal genes are associated with Parkinson's disease (PD), yet the association between PD and ARSA remains unclear., Objectives: To study rare ARSA variants in PD., Methods: To study rare ARSA variants (minor allele frequency < 0.01) in PD, we performed burden analyses in six independent cohorts with 5801 PD patients and 20,475 controls, followed by a meta-analysis., Results: We found evidence for associations between functional ARSA variants and PD in four cohorts (P ≤ 0.05 in each) and in the meta-analysis (P = 0.042). We also found an association between loss-of-function variants and PD in the United Kingdom Biobank cohort (P = 0.005) and in the meta-analysis (P = 0.049). These results should be interpreted with caution as no association survived multiple comparisons correction. Additionally, we describe two families with potential co-segregation of ARSA p.E382K and PD., Conclusions: Rare functional and loss-of-function ARSA variants may be associated with PD. Further replications in large case-control/familial cohorts are required. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society., (© 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.)

Purpose: To evaluate the feasibility and impact of offering genetic testing and counseling to patients with Parkinson's disease (PD), with the potential to enroll in gene-targeted clinical trials and improve clinical care., Methods: A multicenter, exploratory pilot study at 7 academic hospital sites in the United States tracked enrollment and randomized participants to receive results and genetic counseling at local sites or by genetic counselors, remotely. Follow-up surveys measured participant/provider satisfaction, knowledge, and psychological impact., Results: From September 5, 2019 to January 4, 2021, 620 participants were enrolled and 387 completed outcome surveys. There were no significant differences in outcomes between local and remote sites, with both arms reporting high knowledge and satisfaction scores (>80%). Notably, 16% of those tested had reportable PD gene variants (pathogenic/likely pathogenic/risk allele)., Conclusion: Local clinicians, as well as genetic counselors, with educational support as needed, can effectively return genetic results for PD as we observed favorable outcome measures in both groups. Increasing access to PD genetic testing and counseling is urgent; this can inform future efforts to integrate genetic testing and counseling into clinical care for all those with PD., Competing Interests: Conflict of Interest Lola Cook received partial funding of salaries from the Michael J. Fox Foundation (MJFF) and Parkinson’s Foundation; Jennifer Verbrugge received partial funding of salaries from the Michael J. Fox Foundation (MJFF) and Parkinson’s Foundation and received travel funding for Movement Disorders Society International Congress, Madrid, Spain September 2022, abstract and poster presentation PD GENEration Clinical Phase: Genetic Diagnostic Yield and Clinical Characteristics by the Parkinson’s Foundation and paid to Indiana University School of Medicine; Tae-Hwi Schwantes-An, no disclosures; Jeanine Schulze received partial funding of salaries from the MJFF and Parkinson’s Foundation; James C. Beck is employed by the Parkinson’s Foundation, and receives funding for grants through their institution from NIH; Anna Naito is employed by the Parkinson’s Foundation; Anne Hall is a research advocate and received funding of grants from Parkinson’s Foundation for acting as a Steering Committee Member; Amanda K. Chan, no disclosures; Cynthia J. Casaceli, no disclosures; Karen Marder received funding of grants from Parkinson’s Foundation for acting as a Steering Committee Member, receives funding of grants from NIH, MJ FOX, CHDI, HSG, HDSA, Prilenia, Novartis, Roche, Springer, receives consulting fees from Novartis, and receives funding for leadership on Enroll HD Oversight Committee (CHDI) and HSG steering committee; Martha Nance received funding of grants from Parkinson’s Foundation for acting as a Steering Committee Member, received payment for presentation at Parkinson’s Foundation and Parkinson Study Group conferences, received support for attending Parkinson Study Group conference, and is the Chair of Genetics and Environment Working Group for Parkinson Study Group; Michael A. Schwarzschild received funding of grants from Parkinson’s Foundation for acting as a Steering Committee Member, receives funding of grants or conference support from NIH, MJFF, Farmer Family Foundation, Sergey Brin Family Foundation, American Parkinson’s Disease Association, Cure Parkinson’s, Parkinson’s Foundation, Harvard School of Public Health (NIH, DoD), GSK, GE Healthcare, receives consulting fees through Parkinson Study Group for PSG advisory services (including to Bial, Biogen [LUMA/LIGHTHOUSE trials global SC], UCB [ORHCESTRA trial PSG SC]) and through Sutter Health (NIA), Northwestern Univ (NINDS), Cure Parkinson’s for Steering Committee services (for TOPAZ and SPARX3), International Linked Clinical Trial Committee (CP), participates on an Alzheimer’s drug trial Data Monitoring Committee services for Eli Lilly & Co., and is Chair, Exec. Committee for Parkinson Study Group; Tanya Simuni received funding of grants from Parkinson’s Foundation for acting as a Steering Committee Member, receives funding of manuscript by MJFF for Parkinson’s Research, receives funding of grants by Amneal, Biogen, Roche, Neuroderm, Sanofi, Prevail and UCB, is an investigator for NINDS, MJFF, Parkinson’s Foundation studies, receives consulting fees from 4D Pharma, Acadia, AcureX, AskBio, Amneal, Blue Rock Therapeutics, Caraway Therapeutics, Critical Path for Parkinson's Consortium (CPP), Denali, MJFF, Neuroderm, Sanofi, Sinopia, Sunovion, Roche, Takeda, UCB, Vanqua Bio and Voyager, and is on the advisory board for Acadia, AcureX, AskBio, Amneal, Denali, Sunovion, Roche, and on the Scientific Advisory Board for 4D Pharma, Neuroderm, Sanofi and UCB; Anne-Marie Wills received funding of grants from Parkinson’s Foundation for acting as a Steering Committee Member, and receives funding of grants by NIA/NIH, Roche/Genentech, Biogen, and their institution participates on Data Safety Monitoring Board or Advisory Board for Ono Pharmaceuticals and Amylyx Pharmaceuticals; Roy N. Alcalay received funding of grants from Parkinson’s Foundation for acting as a Steering Committee Member, receives funding from NIH, Department of Defense, MJFF, the Silverstein Foundation for GBA/PD and received consulting fees from Sanofi, Ono Therapeutics, Avrobio, Takeda, Gain Therapeutics, Merck, GSK, Caraway., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Parkinson's disease (PD) is the most common neurodegenerative movement disorder, and neuroprotective or disease-modifying interventions remain elusive. High-throughput markers aimed at stratifying patients on the basis of shared etiology are required to ensure the success of disease-modifying therapies in clinical trials. Mitochondrial dysfunction plays a prominent role in the pathogenesis of PD. Previously, we found brain region-specific accumulation of mitochondrial DNA (mtDNA) damage in PD neuronal culture and animal models, as well as in human PD postmortem brain tissue. To investigate mtDNA damage as a potential blood-based marker for PD, we describe herein a PCR-based assay (Mito DNA DX ) that allows for the accurate real-time quantification of mtDNA damage in a scalable platform. We found that mtDNA damage was increased in peripheral blood mononuclear cells derived from patients with idiopathic PD and those harboring the PD-associated leucine-rich repeat kinase 2 ( LRRK2 ) G2019S mutation in comparison with age-matched controls. In addition, mtDNA damage was elevated in non-disease-manifesting LRRK2 mutation carriers, demonstrating that mtDNA damage can occur irrespective of a PD diagnosis. We further established that Lrrk2 G2019S knock-in mice displayed increased mtDNA damage, whereas Lrrk2 knockout mice showed fewer mtDNA lesions in the ventral midbrain, compared with wild-type control mice. Furthermore, a small-molecule kinase inhibitor of LRRK2 mitigated mtDNA damage in a rotenone PD rat midbrain neuron model and in idiopathic PD patient-derived lymphoblastoid cell lines. Quantifying mtDNA damage using the Mito DNA DX assay may have utility as a candidate marker of PD and for measuring the pharmacodynamic response to LRRK2 kinase inhibitors.

Objective: To assess for TDP-43 deposits in brains with and without a LRRK2 G2019S mutation., Background: LRRK2 G2019S mutations have been associated with parkinsonism and a wide range of pathological findings. There are no systematic studies examining the frequency and extent of TDP-43 deposits in neuropathological samples from LRRK2 G2019S carriers., Methods: Twelve brains with LRRK2 G2019S mutations were available for study from the New York Brain Bank at Columbia University; 11 of them had samples available for TDP-43 immunostaining. Clinical, demographic, and pathological data are reported for 11 brains with a LRRK2 G2019S mutation and compared to 11 brains without GBA1 or LRRK2 G2019S mutations with a pathologic diagnosis of Parkinson's disease (PD) or diffuse Lewy body disease. They were frequency matched by age, gender, parkinsonism age of onset, and disease duration., Results: TDP-43 aggregates were present in 73% (n = 8) of brains with a LRRK2 mutation and 18% (n = 2) of brains without a LRRK2 mutation (P = 0.03). In one brain with a LRRK2 mutation, TDP-43 proteinopathy was the primary neuropathological change., Conclusions: Extranuclear TDP-43 aggregates are observed with greater frequency in LRRK2 G2019S autopsies compared to PD cases without a LRRK2 G2019S mutation. The association between LRRK2 and TDP-43 should be further explored. © 2023 International Parkinson and Movement Disorder Society., (© 2023 International Parkinson and Movement Disorder Society.)

Background: Variants in the GBA1 gene, which encodes lysosomal acid glucocerebrosidase, are among the most common genetic risk factors for Parkinson's disease and are associated with faster disease progression. The mechanisms involved are unresolved but might include accumulation of glucosylceramide. Venglustat is a brain-penetrant glucosylceramide synthase inhibitor that, in previous studies, reduced amounts of the glycosphingolipid. We aimed to assess the safety, efficacy, and target engagement of venglustat in people with early-stage Parkinson's disease carrying pathogenic GBA1 variants., Methods: MOVES-PD part 2 was a randomised, double-blinded, placebo-controlled phase 2 study done at 52 centres (academic sites, specialty clinics, and general neurology centres) in 16 countries. Eligible adults aged 18-80 years with Parkinson's disease (Hoehn and Yahr stage ≤2) and one or more GBA1 variants were randomly assigned using an interactive voice-response system (1:1) to 52 weeks of treatment with oral venglustat (15 mg/day) or matching placebo. Investigators, site personnel, participants, and their caregivers were masked to treatment allocation. The primary outcome measure was the change from baseline to 52 weeks in the Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) parts II and III combined score (a higher score indicates greater impairment), and it was analysed in a modified intention-to-treat population (ie, all randomly assigned participants with a baseline and at least one post-baseline measurement during the treatment period). This study was registered with ClinicalTrials.gov (NCT02906020) and is closed to recruitment., Findings: Between Dec 15, 2016, and May 27, 2021, 221 participants were randomly assigned to venglustat (n=110) or placebo (n=111). The least squares mean change in MDS-UPDRS parts II and III combined score was 7·29 (SE 1·36) for venglustat (n=96) and 4·71 (SE 1·27) for placebo (n=105); the absolute difference between groups was 2·58 (95% CI -1·10 to 6·27; p=0·17). The most common treatment-emergent adverse events (TEAEs) were constipation and nausea (both were reported by 23 [21%] of 110 participants in the venglustat group and eight [7%] of 111 participants in the placebo group). Serious TEAEs were reported for 12 (11%) participants in each group. There was one death in the venglustat group owing to an unrelated cardiopulmonary arrest and there were no deaths in the placebo group., Interpretation: In people with GBA1-associated Parkinson's disease in our study, venglustat had a satisfactory safety profile but showed no beneficial treatment effect compared with placebo. These findings indicate that glucosylceramide synthase inhibition with venglustat might not be a viable therapeutic approach for GBA1-associated Parkinson's disease., Funding: Sanofi., Competing Interests: Declaration of interests AHVS declares research support from the UK Medical Research Council, Michael J Fox Foundation (MJFF), Aligning Science Across Parkinson's, and Cure Parkinson's; consulting fees from AvroBio, Auxilius, Coave, Destin, Enterin, Escape Bio, Genilac, and Sanofi; and speaking fees from the Prada Foundation. CRS declares research support from American Parkinson's Disease Foundation, MJFF, US National Institutes of Health (NIH), and US Department of Defense; consulting fees from Sanofi; a patent pending for sphingolipid biomarkers with Brigham and Women's Hospital and Sanofi; scientific advisory board participation for American Parkinson's Disease Foundation; other financial interests from Lysosomal Therapies, MJFF, NIH, Opko, Pfizer, Proteome Sciences, Sanofi, and US Department of Defense; and non-financial interests from Google. GC is an employee of Pythagoras; and declares compensation for consulting and advisory board participation from Alexion, Antisense Therapeutics, Biodelivery Sciences International, Biogen, Clinical Trial Solutions, Genentech, GW Pharmaceuticals, Immunic, Klein Buendel, MedImmune–Viela Bio, MedDay, Merck Serono, NeuroGenesis, Osmotica Pharmaceuticals, Perception Neurosciences, Reckover Pharmaceuticals, Recursion-CereXis Pharmaceuticals, Regeneron, Roche, SAb Biotherapeutics, Sanofi, and TG Therapeutics; data safety monitoring board participation for AI Therapeutics, AMO Pharmaceuticals, Applied Therapeutics, AstraZeneca, AveXis Pharmaceuticals, BioLineRx, BrainStorm Cell Therapeutics, Bristol Myers Squibb-Celgene, CSL Behring, Galmed Pharmaceuticals, Green Valley Pharma, Mapi Pharma, Merck–Pfizer, Mitsubishi Tanabe Pharma, Neurim, Novartis, Ophazyme, Opko Biologics, Reata Pharmaceuticals, Sanofi, Teva Pharmaceuticals, and VielaBio; and protocol review committee participation for the US National Heart, Lung, and Blood Institute. GUH declares compensation for consulting and advisory board participation from AbbVie, Alzprotect, Asceneuron, Biogen, Biohaven, Lundbeck, Novartis, Retrotope, Roche, Sanofi, UCB, and Weston Brain Institute; speaker honoraria from AbbVie, Biogen, Roche, Teva, UCB, and Zambon; data safety monitoring or advisory board participation for Alzprotect and Kainos Medicine; and is a patent holder for treatment of synucleinopathies (US patent number US 10,918,628 B2: EP 17 787 904.6–1109). KM declares consulting fees from Calico, Coave Therapeutics, Invicro, Lundbeck, Lysosomal Therapeutics, MJFF, NeuroDerm, Neuron23, OrbiMed, Roche, Takeda, and UBC. MJP, PM, and SPS are employees of Sanofi and might hold shares, stock options, or both, in the company. NG declares research support from Biogen, EU, Ionis, Israel Science Foundation, MJFF, and US National Parkinson Foundation; consulting fees from AbbVie, Biogen, BOL, Denali Therapeutics, NeuroDerm, Sanofi, and Sionara; speaker honoraria from AbbVie, Movement Disorders Society, and Sanofi; advisory board participation for Biogen, Denali Therapeutics, NeuroDerm, Sanofi, and Sionara; and stock ownership for BOL Pharma, GaitBetter, Lysosomal Therapeutics, and Vibrant. RNA declares research support from NIH, MJFF, Parkinson's Foundation, and US Department of Defense; and consulting fees from AVROBIO, Caraway, Gain Therapeutics, GlaxoSmithKline, Janssen, Merck, Ono Therapeutics, Sanofi, and Takeda. TGa declares research support from the EU, German Research Foundation, German Federal Ministry of Education and Research, Helmholtz Association, and MJFF; speaker honoraria from Bayer, BlueRock Therapeutics, and Coave Therapeutics; compensation for consulting and advisory board participation for MedUpdate, Novartis, Teva, and UCB; and advisory board participation for the EU. TGu declares grants from International Movement Disorders Society; consulting fees from AbbVie, NeuroDerm, Medison, Teva, and TrueMed; honoraria from AbbVie, Medison, and Teva; travel support from AbbVie, Boston Scientific, Medison, and Medtronic; unpaid advisory role or membership for Ezra Le’Marpeh Parkinson's rehabilitation programme, Israeli Huntington Disease Association, Israeli Movement Disorders Society, and Tikvah for Parkinson; stock options for Cytora; previous medical writing assistance from AbbVie and Teva; and planned patents for automated speech analysis and vocal Parkinson's disease biomarkers. TS declares research support from Biogen, MJFF, NeuroDerm, US National Institute of Neurological Disorders and Stroke, Parkinson's Foundation, and Roche; and consulting fees from Acadia, Anavex, Allergan, NeroDerm, MJFF, PhotoPharmics, Revance, Sanofi, Sunovion, Voyager, and US WorldMeds. CP declares no competing interests., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Genetic testing for persons with Parkinson's disease is becoming increasingly common. Significant gains have been made regarding genetic testing methods, and testing is becoming more readily available in clinical, research, and direct-to-consumer settings. Although the potential utility of clinical testing is expanding, there are currently no proven gene-targeted therapies, but clinical trials are underway. Furthermore, genetic testing practices vary widely, as do knowledge and attitudes of relevant stakeholders. The specter of testing mandates financial, ethical, and physician engagement, and there is a need for guidelines to help navigate the myriad of challenges. However, to develop guidelines, gaps and controversies need to be clearly identified and analyzed. To this end, we first reviewed recent literature and subsequently identified gaps and controversies, some of which were partially addressed in the literature, but many of which are not well delineated or researched. Key gaps and controversies include: (1) Is genetic testing appropriate in symptomatic and asymptomatic individuals without medical actionability? (2) How, if at all, should testing vary based on ethnicity? (3) What are the long-term outcomes of consumer- and research-based genetic testing in presymptomatic PD? (4) What resources are needed for clinical genetic testing, and how is this impacted by models of care and cost-benefit considerations? Addressing these issues will help facilitate the development of consensus and guidelines regarding the approach and access to genetic testing and counseling. This is also needed to guide a multidisciplinary approach that accounts for cultural, geographic, and socioeconomic factors in developing testing guidelines. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society., (© 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.)

Background: There is growing clinical and research utilization of genetic testing in Parkinson's disease (PD), including direct-to-consumer testing., Objectives: The aim is to determine the international landscape of genetic testing in PD to inform future worldwide recommendations., Methods: A web-based survey assessing current practices, concerns, and barriers to genetic testing and counseling was administered to the International Parkinson and Movement Disorders Society membership., Results: Common hurdles across sites included cost and access to genetic testing, and counseling, as well as education on genetic counseling. Region-dependent differences in access to and availability of testing and counseling were most notable in Africa. High-income countries also demonstrated heterogeneity, with European nations more likely to have genetic testing covered through insurance than Pan-American and Asian countries., Conclusions: This survey highlights not only diversity of barriers in different regions but also the shared and highly actionable needs for improved education and access to genetic counseling and testing for PD worldwide. © 2023 International Parkinson and Movement Disorder Society., (© 2023 International Parkinson and Movement Disorder Society.)

Background: More than 200 years after James Parkinsondescribed a clinical syndrome based on his astute observations, Parkinson's disease (PD) has evolved into a complex entity, akin to the heterogeneity of other complex human syndromes of the central nervous system such as dementia, motor neuron disease, multiple sclerosis, and epilepsy. Clinicians, pathologists, and basic science researchers evolved arrange of concepts andcriteria for the clinical, genetic, mechanistic, and neuropathological characterization of what, in their best judgment, constitutes PD. However, these specialists have generated and used criteria that are not necessarily aligned between their different operational definitions, which may hinder progress in solving the riddle of the distinct forms of PD and ultimately how to treat them., Objective: This task force has identified current in consistencies between the definitions of PD and its diverse variants in different domains: clinical criteria, neuropathological classification, genetic subtyping, biomarker signatures, and mechanisms of disease. This initial effort for "defining the riddle" will lay the foundation for future attempts to better define the range of PD and its variants, as has been done and implemented for other heterogeneous neurological syndromes, such as stroke and peripheral neuropathy. We strongly advocate for a more systematic and evidence-based integration of our diverse disciplines by looking at well-defined variants of the syndrome of PD., Conclusion: Accuracy in defining endophenotypes of "typical PD" across these different but interrelated disciplines will enable better definition of variants and their stratification in therapeutic trials, a prerequisite for breakthroughs in the era of precision medicine. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society., (© 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.)

Objectives: VPS35 and VPS13 have been associated with Parkinson's disease (PD), and their shared phenotype in yeast when reduced in function is abnormal vacuolar transport. We aim to test if additional potentially deleterious variants in other genes that share this phenotype can modify the risk for PD., Methods: 77 VPS and VPS-related genes were analyzed using whole-genome-sequencing data from 202 PD patients of Ashkenazi Jewish (AJ) ancestry. Filtering was done based on quality and functionality scores. Ten variants in nine genes were further genotyped in 1200 consecutively recruited unrelated AJ-PD patients, and allele frequencies and odds ratio calculated compared to gnomAD-AJ-non-neuro database, in un-stratified (n = 1200) and stratified manner (LRRK2-G2019S-PD patients (n = 145), GBA-PD patients (n = 235), and non-carriers of these mutations (NC, n = 787))., Results: Five variants in PIK3C3, VPS11, AP1G2, HGS and VPS13D were significantly associated with PD-risk. PIK3C3-R768W showed a significant association in an un-stratified (all PDs) analysis, as well as in stratified (LRRK2, GBA, and NC) analyses (Odds ratios = 2.71, 5.32, 3.26. and 2.19 with p = 0.0015, 0.002, 0.0287, and 0.0447, respectively). AP1G2-R563W was significantly associated in LRRK2-carriers (OR = 3.69, p = 0.006) while VPS13D-D2932N was significantly associated in GBA-carriers (OR = 5.45, p = 0.0027). VPS11-C846G and HGS-S243Y were significantly associated in NC (OR = 2.48 and 2.06, with p = 0.022 and 0.0163, respectively)., Conclusions: Variants in genes involved in vesicle-mediated protein transport and recycling pathways, including autophagy and mitophagy, may differentially modify PD-risk in LRRK2-carriers, GBA carriers, or NC. Specifically, PIK3C3-R768W is a PD-risk allele, with the highest effect size in LRRK2-G2019S carriers. These results suggest oligogenic effect that may depends on the genetic background of the patient. An unbiased burden of mutations approach in these genes should be evaluated in additional PD and control groups. The mechanisms by which these novel variants interact and increase PD-risk should be researched in depth for better tailoring therapeutic intervention for PD prevention or slowing disease progression., Competing Interests: Declaration of Competing Interest OG, MGW, SB, VN, ABS, AT, TG, AM, NG, RNA, and AOU have no conflict of interest regarding this manuscript., (Copyright © 2023. Published by Elsevier Inc.)

Introduction: Recent studies found an association between Parkinson's disease (PD) and alterations in the innate immune system. However, whether the involvement of this system in two of the known genetic forms of PD, GBA-PD and LRRK2-PD, and in patients who do not carry these mutations is different, is yet to be determined. We aimed to test if genetic variations in the innate immune genes are differentially associated with PD in these subgroups., Methods: Innate immune genes were identified and classified into sub-lists according to Reactome pathways. Whole-genome-sequencing (WGS) was performed on 201 unrelated Ashkenazi-Jewish (AJ) PD patients including 104 GBA-PD, 32 LRRK2-PD, and 65 non-carriers-PD (NC-PD). To identify genes with different burden between these subgroups of PD, gene-based Sequence kernel association optimal unified test (SKAT-O) analysis was performed on innate immune pathways. Candidate variants within the significant genes were further genotyped in a cohort of 1200 unrelated, consecutively recruited, AJ-PD patients, and to evaluate their association with PD-risk their allele frequencies were compared to AJ-non-neuro cases in gnomAD database, in a stratified and un-stratified manner., Results: SKAT-O analysis showed significantly different burden for PSMB9 (GBA-PD versus NC-PD) and FGR (GBA-PD versus LRRK2-PD). Two candidate variants in PSMB9 showed an association with GBA-PD-risk and NC-PD-risk while one FGR variant showed an association with LRRK2-PD-risk., Conclusion: Our data supports differential involvement of innate immunity risk alleles in PD and emphasizes the differences between the GBA- and LRRK2-PD subgroups., Competing Interests: Declaration of competing interest The authors declare that they have no conflict of interest in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

In conclusion, baseline neuropsychological testing provides a vast amount of unique cognitive, psychiatric, behavioral, and psychosocial information that is useful to individuals with PD, care partners, and treatment team providers. As a baseline examination, it provides opportunities for comparison purposes in the future, a prediction of risk assessment and future treatment needs, and at the time of evaluation for clinical treatment to improve quality of life. Such information is not captured by genetic testing, although the ideal path moving forward would be to perform both neuropsychological testing and genetic testing at baseline., Competing Interests: Declaration of competing interest MKY: Dr. York is funded by the Michael J. Fox Foundation and the Alzheimer's Association. She received consultation fees from the Michael J. Fox Foundation, the Parkinson's Foundation, and Bluerock Therapeutics. RA: Dr. Alcalay is funded by the Michael J. Fox Foundation, the Parkinson's Foundation, and the Silverstein Foundation. His center is funded by research support from Biogen. He received consultation fees from Sanofi, Takeda and Gain Therapeutics., (Copyright © 2023. Published by Elsevier Ltd.)

Background: Mutations in the leucine-rich repeat kinase 2 (LRRK2) gene have been recognized as genetic risk factors for Parkinson's disease (PD). However, compared to cancer, fewer genetic mutations contribute to the cause of PD, propelling the search for protein biomarkers for early detection of the disease., Methods: Utilizing 138 urine samples from four groups, healthy individuals (control), healthy individuals with G2019S mutation in the LRRK2 gene (non-manifesting carrier/NMC), PD individuals without G2019S mutation (idiopathic PD/iPD), and PD individuals with G2019S mutation (LRRK2 PD), we applied a proteomics strategy to determine potential diagnostic biomarkers for PD from urinary extracellular vesicles (EVs)., Results: After efficient isolation of urinary EVs through chemical affinity followed by mass spectrometric analyses of EV peptides and enriched phosphopeptides, we identify and quantify 4476 unique proteins and 2680 unique phosphoproteins. We detect multiple proteins and phosphoproteins elevated in PD EVs that are known to be involved in important PD pathways, in particular the autophagy pathway, as well as neuronal cell death, neuroinflammation, and formation of amyloid fibrils. We establish a panel of proteins and phosphoproteins as novel candidates for disease biomarkers and substantiate the biomarkers using machine learning, ROC, clinical correlation, and in-depth network analysis. Several putative disease biomarkers are further partially validated in patients with PD using parallel reaction monitoring (PRM) and immunoassay for targeted quantitation., Conclusions: These findings demonstrate a general strategy of utilizing biofluid EV proteome/phosphoproteome as an outstanding and non-invasive source for a wide range of disease exploration., (© 2023. The Author(s).)

The association between glucocerebrosidase, encoded by GBA, and Parkinson's disease (PD) highlights the role of the lysosome in PD pathogenesis. Genome-wide association studies in PD have revealed multiple associated loci, including the GALC locus on chromosome 14. GALC encodes the lysosomal enzyme galactosylceramidase, which plays a pivotal role in the glycosphingolipid metabolism pathway. It is still unclear whether GALC is the gene driving the association in the chromosome 14 locus and, if so, by which mechanism. We first aimed to examine whether variants in the GALC locus and across the genome are associated with galactosylceramidase activity. We performed a genome-wide association study in two independent cohorts from (i) Columbia University; and (ii) the Parkinson's Progression Markers Initiative study, followed by a meta-analysis with a total of 976 PD patients and 478 controls with available data on galactosylceramidase activity. We further analysed the effects of common GALC variants on expression and galactosylceramidase activity using genomic colocalization methods. Mendelian randomization was used to study whether galactosylceramidase activity may be causal in PD. To study the role of rare GALC variants, we analysed sequencing data from 5028 PD patients and 5422 controls. Additionally, we studied the functional impact of GALC knockout on alpha-synuclein accumulation and on glucocerebrosidase activity in neuronal cell models and performed in silico structural analysis of common GALC variants associated with altered galactosylceramidase activity. The top hit in PD genome-wide association study in the GALC locus, rs979812, is associated with increased galactosylceramidase activity (b = 1.2; SE = 0.06; P = 5.10 × 10-95). No other variants outside the GALC locus were associated with galactosylceramidase activity. Colocalization analysis demonstrated that rs979812 was also associated with increased galactosylceramidase expression. Mendelian randomization suggested that increased galactosylceramidase activity may be causally associated with PD (b = 0.025, SE = 0.007, P = 0.0008). We did not find an association between rare GALC variants and PD. GALC knockout using CRISPR-Cas9 did not lead to alpha-synuclein accumulation, further supporting that increased rather than reduced galactosylceramidase levels may be associated with PD. The structural analysis demonstrated that the common variant p.I562T may lead to improper maturation of galactosylceramidase affecting its activity. Our results nominate GALC as the gene associated with PD in this locus and suggest that the association of variants in the GALC locus may be driven by their effect of increasing galactosylceramidase expression and activity. Whether altering galactosylceramidase activity could be considered as a therapeutic target should be further studied., (© The Author(s) 2022. Published by Oxford University Press on behalf of the Guarantors of Brain.)

Background: Biallelic pathogenic variants in GBA1 are the cause of Gaucher disease (GD) type 1 (GD1), a lysosomal storage disorder resulting from deficient glucocerebrosidase. Heterozygous GBA1 variants are also a common genetic risk factor for Parkinson's disease (PD). GD manifests with considerable clinical heterogeneity and is also associated with an increased risk for PD., Objective: The objective of this study was to investigate the contribution of PD risk variants to risk for PD in patients with GD1., Methods: We studied 225 patients with GD1, including 199 without PD and 26 with PD. All cases were genotyped, and the genetic data were imputed using common pipelines., Results: On average, patients with GD1 with PD have a significantly higher PD genetic risk score than those without PD (P = 0.021)., Conclusions: Our results indicate that variants included in the PD genetic risk score were more frequent in patients with GD1 who developed PD, suggesting that common risk variants may affect underlying biological pathways. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of 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 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of 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: Emerging evidence shows that α-synuclein seed amplification assays (SAAs) have the potential to differentiate people with Parkinson's disease from healthy controls. We used the well characterised, multicentre Parkinson's Progression Markers Initiative (PPMI) cohort to further assess the diagnostic performance of the α-synuclein SAA and to examine whether the assay identifies heterogeneity among patients and enables the early identification of at-risk groups., Methods: This cross-sectional analysis is based on assessments done at enrolment for PPMI participants (including people with sporadic Parkinson's disease from LRRK2 and GBA variants, healthy controls, prodromal individuals with either rapid eye movement sleep behaviour disorder (RBD) or hyposmia, and non-manifesting carriers of LRRK2 and GBA variants) from 33 participating academic neurology outpatient practices worldwide (in Austria, Canada, France, Germany, Greece, Israel, Italy, the Netherlands, Norway, Spain, the UK, and the USA). α-synuclein SAA analysis of CSF was performed using previously described methods. We assessed the sensitivity and specificity of the α-synuclein SAA in participants with Parkinson's disease and healthy controls, including subgroups based on genetic and clinical features. We established the frequency of positive α-synuclein SAA results in prodromal participants (RBD and hyposmia) and non-manifesting carriers of genetic variants associated with Parkinson's disease, and compared α-synuclein SAA to clinical measures and other biomarkers. We used odds ratio estimates with 95% CIs to measure the association between α-synuclein SAA status and categorical measures, and two-sample 95% CIs from the resampling method to assess differences in medians between α-synuclein SAA positive and negative participants for continuous measures. A linear regression model was used to control for potential confounders such as age and sex., Findings: This analysis included 1123 participants who were enrolled between July 7, 2010, and July 4, 2019. Of these, 545 had Parkinson's disease, 163 were healthy controls, 54 were participants with scans without evidence of dopaminergic deficit, 51 were prodromal participants, and 310 were non-manifesting carriers. Sensitivity for Parkinson's disease was 87·7% (95% CI 84·9-90·5), and specificity for healthy controls was 96·3% (93·4-99·2). The sensitivity of the α-synuclein SAA in sporadic Parkinson's disease with the typical olfactory deficit was 98·6% (96·4-99·4). The proportion of positive α-synuclein SAA was lower than this figure in subgroups including LRRK2 Parkinson's disease (67·5% [59·2-75·8]) and participants with sporadic Parkinson's disease without olfactory deficit (78·3% [69·8-86·7]). Participants with LRRK2 variant and normal olfaction had an even lower α-synuclein SAA positivity rate (34·7% [21·4-48·0]). Among prodromal and at-risk groups, 44 (86%) of 51 of participants with RBD or hyposmia had positive α-synuclein SAA (16 of 18 with hyposmia, and 28 of 33 with RBD). 25 (8%) of 310 non-manifesting carriers (14 of 159 [9%] LRRK2 and 11 of 151 [7%] GBA) were positive., Interpretation: This study represents the largest analysis so far of the α-synuclein SAA for the biochemical diagnosis of Parkinson's disease. Our results show that the assay classifies people with Parkinson's disease with high sensitivity and specificity, provides information about molecular heterogeneity, and detects prodromal individuals before diagnosis. These findings suggest a crucial role for the α-synuclein SAA in therapeutic development, both to identify pathologically defined subgroups of people with Parkinson's disease and to establish biomarker-defined at-risk cohorts., Funding: PPMI is funded by the Michael J Fox Foundation for Parkinson's Research and funding partners, including: Abbvie, AcureX, Aligning Science Across Parkinson's, Amathus Therapeutics, Avid Radiopharmaceuticals, Bial Biotech, Biohaven, Biogen, BioLegend, Bristol-Myers Squibb, Calico Labs, Celgene, Cerevel, Coave, DaCapo Brainscience, 4D Pharma, Denali, Edmond J Safra Foundation, Eli Lilly, GE Healthcare, Genentech, GlaxoSmithKline, Golub Capital, Insitro, Janssen Neuroscience, Lundbeck, Merck, Meso Scale Discovery, Neurocrine Biosciences, Prevail Therapeutics, Roche, Sanofi Genzyme, Servier, Takeda, Teva, UCB, VanquaBio, Verily, Voyager Therapeutics, and Yumanity., Competing Interests: Declaration of interests AS declares consultancy for Merck, Parkinson Study Group; and honoraria from Bial. LC-M declares employment for Amprion; stock ownership (employee stock options) for Amprion; and patent or patent applications numbers US 20210277076A1, US 20210311077A1, US 20190353669A1, and US 20210223268A1. CMF declares employment for Amprion; stock ownership (employee stock options) for Amprion; and patent or patent applications numbers US 20210277076A1 and US 20210311077A1. YM declares employment for Amprion; stock ownership (employee stock options) for Amprion; and patent or patent applications number US 20210277076A1. PAU declares employment for Amprion; and stock ownership (employee stock options) for Amprion. HN declares employment for Amprion; and stock ownership (employee stock options) for Amprion. RNA declares consultancies for Janssen, Sanofi, Ono Therapuetics, Avrobio, Takeda, Gain Therapuetics, Merck, GlaxoSmithKline, and Caraway. LMC declares honoraria (royalties) from Elsevier and Wolters Kluwel. TF declares travel grants from the Michael J Fox Foundation. KMe declares consultancies for the Michael J Fox Foundation, AcuRx, Caraway, Cerebral Therapeutics, NRG Therapeutics (scientific advisory board), Nurabio, Retromer Therapeutics (director on the board, part-time chief scientific officer), Schrodinger, Sinopia Biosciences (scientific advisory board), and Vanqua Biosciences (scientific advisory board); stock ownership for Cognition Therapeutics, Eli Lilly (retiree stock holder), Envisagenics, and Retromer Therapeutics; honoraria for the University of Utah; patents or patent applications for Retromer Therapeutics (planned patent); and travel grants from the University of Utah. BM declares consultancies from Roche, Biogen, and the Michael J Fox Foundation; honoraria for Abbvie; and travel grants for Abbvie. KLP declares consultancies for Curasen; was on a scientific advisory board for Curasen and Amprion; honoraria from invited scientific presentations to universities and professional societies not exceeding $5000 per year from California Congress of Clinical Neurology, California Neurological Society, and Johns Hopkins University; and patents or patent applications numbers 17/314,979 and 63/377,293. JS declares consultancies from Invicro, Biogen, and Abbvie; and stock ownership from RealmIDX, MNI Holdings, and LikeMinds. TSi declares consultancies for 4D Pharma, Acadia, AcureX, AskBio, Amneal, Blue Rock Therapeutics, Caraway, Critical Path for Parkinson's Consortium, Denali, Michael J Fox Foundation, Neuroderm, Roche, Sanofi, Sinopia, Sunovion, Takeda, UCB, Vanqua Bio, and Voyager. CMT declares consultancies for CNS Ratings, Australian Parkinson's Mission, Biogen, Evidera, Cadent (data safety monitoring board), Adamas (steering committee), Biogen (via the Parkinson Study Group steering committee), Kyowa Kirin (advisory board), Lundbeck (advisory board), Jazz/Cavion (steering committee), and Acorda (advisory board). DW declares receiving salary support from Michael J Fox Foundation for serving on an Executive Steering Committee for the PPMI. AV declares consultancies for CoA Therapeutics, XW Pharma, and Biogen. MF declares employment for the Michael J Fox Foundation. LMAO declares employment for the Michael J Fox Foundation. SJH declares employment for the Michael J Fox Foundation. TSh declares employment for the Michael J Fox Foundation. KMa declares consultancies for Invicro, MJFF, Roche, Calico, Coave, Neuron23, Orbimed, Neuroderm, Sanofi, Takeda, Merck, Lilly, Inhibikase, and Neuramedy. CS declares employment for Amprion; stock ownership for Amprion; honoraria (will receive royalties for the sale of seed amplification assay [SAA]) from Amprion; and patents or patent applications, awarded and amplified in conjunction with Amprion for the SAA assay., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

We quantified concentrations of three isoforms of the endolysosomal lipid, bis(monoacylglycerol) phosphate (BMP) in the urine of deeply phenotyped cohorts in the Parkinson's Progression Markers Initiative: LRRK2 G2019S PD (N = 134) and non-manifesting carriers (NMC) (G2019S+ NMC; N = 182), LRRK2 R1441G PD (N = 15) and R1441G+ NMC (N = 15), GBA1 N409S PD (N = 76) and N409S+ NMC (N = 178), sporadic PD (sPD, N = 379) and healthy controls (HC) (N = 190). The effects of each mutation and disease status were analyzed using nonparametric methods. Longitudinal changes in BMP levels were analyzed using linear mixed models. At baseline, all LRRK2 carriers had 3-7× higher BMP levels compared to HC, irrespective of the disease status. GBA1 N409S carriers also showed significant, albeit smaller, elevation (~30-40%) in BMP levels compared to HC. In LRRK2 G2019S PD, urinary BMP levels remained stable over two years. Furthermore, baseline BMP levels did not predict disease progression as measured by striatal DaT imaging, MDS-UPDRS III Off, or MoCA in any of the cohorts. These data support the utility of BMP as a target modulation biomarker in therapeutic trials of genetic and sPD but not as a prognostic or disease progression biomarker., (© 2023. The Author(s).)

Background: As gene-targeted therapies are increasingly being developed for Parkinson's disease (PD), identifying and characterizing carriers of specific genetic pathogenic variants is imperative. Only a small fraction of the estimated number of subjects with monogenic PD worldwide are currently represented in the literature and availability of clinical data and clinical trial-ready cohorts is limited., Objective: The objectives are to (1) establish an international cohort of affected and unaffected individuals with PD-linked variants; (2) provide harmonized and quality-controlled clinical characterization data for each included individual; and (3) further promote collaboration of researchers in the field of monogenic PD., Methods: We conducted a worldwide, systematic online survey to collect individual-level data on individuals with PD-linked variants in SNCA, LRRK2, VPS35, PRKN, PINK1, DJ-1, as well as selected pathogenic and risk variants in GBA and corresponding demographic, clinical, and genetic data. All registered cases underwent thorough quality checks, and pathogenicity scoring of the variants and genotype-phenotype relationships were analyzed., Results: We collected 3888 variant carriers for our analyses, reported by 92 centers (42 countries) worldwide. Of the included individuals, 3185 had a diagnosis of PD (ie, 1306 LRRK2, 115 SNCA, 23 VPS35, 429 PRKN, 75 PINK1, 13 DJ-1, and 1224 GBA) and 703 were unaffected (ie, 328 LRRK2, 32 SNCA, 3 VPS35, 1 PRKN, 1 PINK1, and 338 GBA). In total, we identified 269 different pathogenic variants; 1322 individuals in our cohort (34%) were indicated as not previously published., Conclusions: Within the MJFF Global Genetic PD Study Group, we (1) established the largest international cohort of affected and unaffected individuals carrying PD-linked variants; (2) provide harmonized and quality-controlled clinical and genetic data for each included individual; (3) promote collaboration in the field of genetic PD with a view toward clinical and genetic stratification of patients for gene-targeted clinical trials. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society., (© 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.)