Relevance of genetic testing in the gene-targeted trial era: the Rostock Parkinson's disease study.

Estimates of the spectrum and frequency of pathogenic variants in Parkinson's disease (PD) in different populations are currently limited and biased. Furthermore, although therapeutic modification of several genetic targets has reached the clinical trial stage, a major obstacle in conducting these trials is that PD patients are largely unaware of their genetic status and, therefore, cannot be recruited. Expanding the number of investigated PD-related genes and including genes related to disorders with overlapping clinical features in large, well-phenotyped PD patient groups is a prerequisite for capturing the full variant spectrum underlying PD and for stratifying and prioritizing patients for gene-targeted clinical trials. The Rostock Parkinson's disease (ROPAD) study is an observational clinical study aiming to determine the frequency and spectrum of genetic variants contributing to PD in a large international cohort. We investigated variants in 50 genes with either an established relevance for PD or possible phenotypic overlap in a group of 12 580 PD patients from 16 countries [62.3% male; 92.0% White; 27.0% positive family history (FH+), median age at onset (AAO) 59 years] using a next-generation sequencing panel. Altogether, in 1864 (14.8%) ROPAD participants (58.1% male; 91.0% White, 35.5% FH+, median AAO 55 years), a PD-relevant genetic test (PDGT) was positive based on GBA1 risk variants (10.4%) or pathogenic/likely pathogenic variants in LRRK2 (2.9%), PRKN (0.9%), SNCA (0.2%) or PINK1 (0.1%) or a combination of two genetic findings in two genes (∼0.2%). Of note, the adjusted positive PDGT fraction, i.e. the fraction of positive PDGTs per country weighted by the fraction of the population of the world that they represent, was 14.5%. Positive PDGTs were identified in 19.9% of patients with an AAO ≤ 50 years, in 19.5% of patients with FH+ and in 26.9% with an AAO ≤ 50 years and FH+. In comparison to the idiopathic PD group (6846 patients with benign variants), the positive PDGT group had a significantly lower AAO (4 years, P = 9 × 10-34). The probability of a positive PDGT decreased by 3% with every additional AAO year (P = 1 × 10-35). Female patients were 22% more likely to have a positive PDGT (P = 3 × 10-4), and for individuals with FH+ this likelihood was 55% higher (P = 1 × 10-14). About 0.8% of the ROPAD participants had positive genetic testing findings in parkinsonism-, dystonia/dyskinesia- or dementia-related genes. In the emerging era of gene-targeted PD clinical trials, our finding that ∼15% of patients harbour potentially actionable genetic variants offers an important prospect to affected individuals and their families and underlines the need for genetic testing in PD patients. Thus, the insights from the ROPAD study allow for data-driven, differential genetic counselling across the spectrum of different AAOs and family histories and promote a possible policy change in the application of genetic testing as a routine part of patient evaluation and care in PD.

Team Science Approaches to Unravel Monogenic Parkinson's Disease on a Global Scale.

BACKGROUND: Until recently, about three-quarters of all monogenic Parkinson's disease (PD) studies were performed in European/White ancestry, thereby severely limiting our insights into genotype-phenotype relationships at a global scale. OBJECTIVE: To identify the multi-ancestry spectrum of monogenic PD. METHODS: The first systematic approach to embrace monogenic PD worldwide, The Michael J. Fox Foundation Global Monogenic PD Project, contacted authors of publications reporting individuals carrying pathogenic variants in known PD-causing genes. In contrast, the Global Parkinson's Genetics Program's Monogenic Network took a different approach by targeting PD centers underrepresented or not yet represented in the medical literature. RESULTS: In this article, we describe combining both efforts in a merger project resulting in a global monogenic PD cohort with the buildup of a sustainable infrastructure to identify the multi-ancestry spectrum of monogenic PD and enable studies of factors modifying penetrance and expressivity of monogenic PD. CONCLUSIONS: This effort demonstrates the value of future research based on team science approaches to generate comprehensive and globally relevant results. © 2024 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Genetic Risk Factors in Isolated Dystonia Escape Genome-Wide Association Studies.

BACKGROUND: Despite considerable heritability, previous smaller genome-wide association studies (GWASs) have not identified any robust genetic risk factors for isolated dystonia. OBJECTIVE: The objective of this study was to perform a large-scale GWAS in a well-characterized, multicenter sample of >6000 individuals to identify genetic risk factors for isolated dystonia. METHODS: Array-based GWASs were performed on autosomes for 4303 dystonia participants and 2362 healthy control subjects of European ancestry with subgroup analysis based on age at onset, affected body regions, and a newly developed clinical score. Another 736 individuals were used for validation. RESULTS: This GWAS identified no common genome-wide significant loci that could be replicated despite sufficient power to detect meaningful effects. Power analyses imply that the effects of individual variants are likely very small. CONCLUSIONS: Moderate single-nucleotide polymorphism-based heritability indicates that common variants do not contribute to isolated dystonia in this cohort. Sequence-based GWASs (eg, by whole-genome sequencing) might help to better understand the genetic basis. © 2024 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Embracing Monogenic Parkinson's Disease: The MJFF Global Genetic PD Cohort.

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.

Protocol of the Luebeck longitudinal investigation of SARS-CoV-2 infection (ELISA) study - a prospective population-based cohort study.

BACKGROUND: Considering the insufficiently controlled spread of new SARS-CoV-2 variants, partially low vaccination rates, and increased risk of a post-COVID syndrome, well-functioning, targeted intervention measures at local and national levels are urgently needed to contain the SARS-CoV-2 pandemic. Surveillance concepts (cross-sectional, cohorts, clusters) need to be carefully selected to monitor and assess incidence and prevalence at the population level. A critical methodological gap for identifying specific risks/dynamics for SARS-Cov-2 transmission and post-COVID-19-syndrome includes repetitive testing for past or present infection of a defined cohort with simultaneous assessment of symptoms, behavior, risk, and protective factors, as well as quality of life. METHODS: The ELISA-Study is a longitudinal, prospective surveillance study with a cohort approach launched in Luebeck in April 2020. The first part comprised regular PCR testing, antibody measurements, and a recurrent App-based questionnaire for a population-based cohort of 3000 inhabitants of Luebeck. The follow-up study protocol includes self-testing for antibodies and PCR testing for a subset of the participants, focusing on studying immunity after vaccination and/or infection and post-COVID-19 symptoms. DISCUSSION: The ELISA cohort and our follow-up study protocol will enable us to study the effects of a sharp increase of SARS-CoV-2 infections on seroprevalence of Anti-SARS-CoV-2 antibodies, post-COVID-19-symptoms, and possible medical, occupational, and behavioral risk factors. We will be able to monitor the pandemic continuously and discover potential sequelae of an infection long-term. Further examinations can be readily set up on an ad-hoc basis in the future. Our study protocol can be adapted to other regions and settings and is transferable to other infectious diseases. TRIAL REGISTRATION: DRKS.de, German Clinical Trials Register (DRKS), Identifier: DRKS00023418 , Registered on 28 October 2020.

Genotype-Phenotype Relations for the Atypical Parkinsonism Genes: MDSGene Systematic Review.

This Movement Disorder Society Genetic mutation database Systematic Review focuses on monogenic atypical parkinsonism with mutations in the ATP13A2, DCTN1, DNAJC6, FBXO7, SYNJ1, and VPS13C genes. We screened 673 citations and extracted genotypic and phenotypic data for 140 patients (73 families) from 77 publications. In an exploratory fashion, we applied an automated classification procedure via an ensemble of bootstrap-aggregated ("bagged") decision trees to distinguish these 6 forms of monogenic atypical parkinsonism and found a high accuracy of 86.5% (95%CI, 86.3%-86.7%) based on the following 10 clinical variables: age at onset, spasticity and pyramidal signs, hypoventilation, decreased body weight, minimyoclonus, vertical gaze palsy, autonomic symptoms, other nonmotor symptoms, levodopa response quantification, and cognitive decline. Comparing monogenic atypical with monogenic typical parkinsonism using 2063 data sets from Movement Disorder Society Genetic mutation database on patients with SNCA, LRRK2, VPS35, Parkin, PINK1, and DJ-1 mutations, the age at onset was earlier in monogenic atypical parkinsonism (24 vs 40 years; P = 1.2647 × 10-12) and levodopa response less favorable than in patients with monogenic typical presentations (49% vs 93%). In addition, we compared monogenic to nonmonogenic atypical parkinsonism using data from 362 patients with progressive supranuclear gaze palsy, corticobasal degeneration, multiple system atrophy, or frontotemporal lobar degeneration. Although these conditions share many clinical features with the monogenic atypical forms, they can typically be distinguished based on their later median age at onset (64 years; IQR, 57-70 years). In conclusion, age at onset, presence of specific signs, and degree of levodopa response inform differential diagnostic considerations and genetic testing indications in atypical forms of parkinsonism. © 2021 International Parkinson and Movement Disorder Society.

The Rostock International Parkinson's Disease (ROPAD) Study: Protocol and Initial Findings.

BACKGROUND: Genetic stratification of Parkinson's disease (PD) patients facilitates gene-tailored research studies and clinical trials. The objective of this study was to describe the design of and the initial data from the Rostock International Parkinson's Disease (ROPAD) study, an epidemiological observational study aiming to genetically characterize ~10,000 participants. METHODS: Recruitment criteria included (1) clinical diagnosis of PD, (2) relative of participant with a reportable LRRK2 variant, or (3) North African Berber or Ashkenazi Jew. DNA analysis involved up to 3 successive steps: (1) variant (LRRK2) and gene (GBA) screening, (2) panel sequencing of 68 PD-linked genes, and (3) genome sequencing. RESULTS: Initial data based on the first 1360 participants indicated that the ROPAD enrollment strategy revealed a genetic diagnostic yield of ~14% among a PD cohort from tertiary referral centers. CONCLUSIONS: The ROPAD screening protocol is feasible for high-throughput genetic characterization of PD participants and subsequent prioritization for gene-focused research efforts and clinical trials. © 2020 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Genotype-Phenotype Relations for the Parkinson's Disease Genes Parkin, PINK1, DJ1: MDSGene Systematic Review.

This first comprehensive MDSGene review is devoted to the 3 autosomal recessive Parkinson's disease forms: PARK-Parkin, PARK-PINK1, and PARK-DJ1. It followed MDSGene's standardized data extraction protocol and screened a total of 3652 citations and is based on fully curated phenotypic and genotypic data on >1100 patients with recessively inherited PD because of 221 different disease-causing mutations in Parkin, PINK1, or DJ1. All these data are also available in an easily searchable online database (www.mdsgene.org), which also provides descriptive summary statistics on phenotypic and genetic data. Despite the high degree of missingness of phenotypic features and unsystematic reporting of genotype data in the original literature, the present review recapitulates many of the previously described findings including early onset (median age at onset of ∼30 years for carriers of at least 2 mutations in any of the 3 genes) of an overall clinically typical form of PD with excellent treatment response, dystonia and dyskinesia being relatively common and cognitive decline relatively uncommon. However, when comparing actual data with common expert knowledge in previously published reviews, we detected several discrepancies. We conclude that systematic reporting of phenotypes is a pressing need in light of increasingly available molecular genetic testing and the emergence of first gene-specific therapies entering clinical trials. © 2018 International Parkinson and Movement Disorder Society.

Validation of conversion between mini-mental state examination and montreal cognitive assessment.

INTRODUCTION: Harmonizing data across cohorts is important for validating findings or combining data in meta-analyses. We replicate and validate a previous conversion of MoCA to MMSE in PD. METHODS: We used five studies with 1,161 PD individuals and 2,091 observations measured with both the MoCA and MMSE. We compared a previously published conversion table using equipercentile equating with log-linear smoothing to our internally derived scores. RESULTS: Both conversions found good agreement within and across the studies when comparing true and converted MMSE (mean difference: 0.05; standard deviation: 1.84; median difference: 0; interquartile range: -1 to 1, using internal conversion). CONCLUSIONS: These results show that one can get a reliable and valid conversion between two commonly used measures of cognition in PD studies. These approaches need to be applied to other scales and domains to enable large-scale collaborative analyses across multiple PD cohorts.

A population-based study on combined markers for early Parkinson's disease.

The prerequisite for an earlier diagnosis of Parkinson's disease (PD) are markers that are both sensitive and specific for clinically definite PD and its prediagnosic phases. Promising candidates include enlarged hyperechogenicity of the substantia nigra (SN+) on transcranial sonography (TCS) and hyposmia. However, despite good sensitivity and specificity, both markers have yet failed to yield reliable predictions. We pursue the possibility of combined use in an ongoing population-based cohort. Subjects were recruited from 10,000 inhabitants of Luebeck/Germany aged 50 to 79 years and additional PD patients from our outpatient clinic. After neurological examination, 715 subjects were grouped into clinically definite PD (n = 106), possible prediagnostic PD (ppPD; n = 73), and a control group subdivided into healthy individuals (n = 283) and controls with diseases other than PD (n = 253). Subjects underwent TCS and smell testing. Sensitivity and specificity of SN+ and hyposmia were good for PD; however, positive predictive values (PPV) of both SN+ (5.2%) and olfaction (2.5%) were low. At least one positive/both positive markers were present in 33%/1% of healthy controls, 33%/2% of diseased controls, 62%/7% of ppPD, and 94%/51% of PD. When combining SN+ and hyposmia, PPV increased to 17.6%, with a sensitivity of 51% and a specificity of 98%. Both SN+ and hyposmia offer good enrichment towards PD and ppPD, are stable against other diseases, and the combination of markers highly increases specificity. However, if the combination of SN+ and hyposmia were used as criterion for PD diagnosis, almost half of clinically definite PD and more than 90% of ppPD would have been missed.

Understanding monogenic Parkinson's disease at a global scale.

Until recently, about three-quarters of all monogenic Parkinson's disease (PD) studies were performed in European/White ancestry, thereby severely limiting our insights into genotype-phenotype relationships at global scale. The first systematic approach to embrace monogenic PD worldwide, The Michael J. Fox Foundation Global Monogenic PD (MJFF GMPD) Project, contacted authors of publications reporting individuals carrying pathogenic variants in known PD-causing genes. In contrast, the Global Parkinson's Genetics Program's (GP2) Monogenic Network took a different approach by targeting PD centers not yet represented in the medical literature. Here, we describe combining both efforts in a "merger project" resulting in a global monogenic PD cohort with build-up of a sustainable infrastructure to identify the multi-ancestry spectrum of monogenic PD and enable studies of factors modifying penetrance and expression of monogenic PD. This effort demonstrates the value of future research based on team science approaches to generate comprehensive and globally relevant results.

Depressive symptoms in Parkinson's disease are insufficiently but more often treated than in other chronic conditions.

Depressive symptoms in Parkinson's disease (PD) are multifactorial and are partly linked to the underlying dopaminergic deficit. However, at least a subset of PD patients may exhibit an unspecific depressive reaction to chronic illness. Here, we compared the prevalence and severity of depressive symptoms in PD patients and disease controls (DC). PD patients reported depressive symptoms at similar frequencies as DC but were on antidepressants, especially Mirtazapine, more frequently. Still, in both groups, a high proportion of patients with clinically significant depressive symptoms was not receiving medication. Diagnosis and treatment of depressive symptoms both in PD and DC should be improved.

Establishing an online resource to facilitate global collaboration and inclusion of underrepresented populations: Experience from the MJFF Global Genetic Parkinson's Disease Project.

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.

Coffee, smoking and aspirin are associated with age at onset in idiopathic Parkinson's disease.

Parkinson's disease (PD) is a progressive neurodegenerative disorder. Genetic modifiers, environmental factors and gene-environment interactions have been found to modify PD risk and disease progression. The objective of this study was to evaluate the association of smoking, caffeine and anti-inflammatory drugs with age at onset (AAO) in a large PD cohort. A total of 35,963 American patients with idiopathic PD (iPD) from the Fox Insight Study responded to health and lifestyle questionnaires. We compared the median AAO between different groups using the non-parametric Mann-Whitney U test. Non-parametric Spearman's correlation was used for correlation assessments and regression analysis was used to assess interaction between variables. We found that smoking (p < 0.0001), coffee drinking (p < 0.0001) and aspirin intake (p < 0.0001) show an exploratory association with AAO in PD, that was further supported by multivariate regression models. The association of aspirin with PD AAO was replicated in another cohort (EPIPARK) (n = 237 patients with PD).

One-year surveillance of SARS-CoV-2 transmission of the ELISA cohort: A model for population-based monitoring of infection risk.

With newly rising coronavirus disease 2019 (COVID-19) cases, important data gaps remain on (i) long-term dynamics of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection rates in fixed cohorts (ii) identification of risk factors, and (iii) establishment of effective surveillance strategies. By polymerase chain reaction and antibody testing of 1% of the local population and >90,000 app-based datasets, the present study surveilled a catchment area of 300,000 inhabitants from March 2020 to February 2021. Cohort (56% female; mean age, 45.6 years) retention was 75 to 98%. Increased risk for seropositivity was detected in several high-exposure groups, especially nurses. Unreported infections dropped from 92 to 29% during the study. "Contact to COVID-19-affected" was the strongest risk factor, whereas public transportation, having children in school, or tourism did not affect infection rates. With the first SARS-CoV-2 cohort study, we provide a transferable model for effective surveillance, enabling monitoring of reinfection rates and increased preparedness for future pandemics.

Persistent cognitive impairment associated with cerebrospinal fluid anti-SARS-CoV-2 antibodies six months after mild COVID-19.

Neurological long-term sequelae are increasingly considered an important challenge in the recent COVID-19 pandemic. However, most evidence for neurological symptoms after SARS-CoV-2 infection and central nervous system invasion of the virus stems from individuals severely affected in the acute phase of the disease. Here, we report long-lasting cognitive impairment along with persistent cerebrospinal fluid anti-SARS-CoV-2 antibodies in a female patient with unremarkable standard examination 6 months after mild COVID-19, supporting the implementation of neuropsychological testing and specific cerebrospinal fluid investigation also in patients with a relatively mild acute disease phase.

Validity and Prognostic Value of a Polygenic Risk Score for Parkinson's Disease.

Idiopathic Parkinson's disease (PD) is a complex multifactorial disorder caused by the interplay of both genetic and non-genetic risk factors. Polygenic risk scores (PRSs) are one way to aggregate the effects of a large number of genetic variants upon the risk for a disease like PD in a single quantity. However, reassessment of the performance of a given PRS in independent data sets is a precondition for establishing the PRS as a valid tool to this end. We studied a previously proposed PRS for PD in a separate genetic data set, comprising 1914 PD cases and 4464 controls, and were able to replicate its ability to differentiate between cases and controls. We also assessed theoretically the prognostic value of the PD-PRS, i.e., its ability to predict the development of PD in later life for healthy individuals. As it turned out, the PD-PRS alone can be expected to perform poorly in this regard. Therefore, we conclude that the PD-PRS could serve as an important research tool, but that meaningful PRS-based prognosis of PD at an individual level is not feasible.