scholarly journals Identification of LRRK2 missense variants in the accelerating medicines partnership Parkinson’s disease cohort

2021 ◽  
Author(s):  
Nicole Bryant ◽  
Nicole Malpeli ◽  
Julia Ziaee ◽  
Cornelis Blauwendraat ◽  
Zhiyong Liu ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Association Studies ◽  
Missense Variant ◽  
Computational Prediction ◽  
Genome Wide Association Studies ◽  
Cumulative Impact ◽  
Missense Variants ◽  
Variants Of Unknown Significance ◽  
High Pathogenicity

Abstract Pathogenic missense variants in the leucine-rich repeat kinase 2 (LRRK2) gene have been identified through linkage analysis in familial Parkinson disease (PD). Subsequently, other missense variants with lower effect sizes on PD risk have emerged, as well as non-coding polymorphisms (e.g. rs76904798) enriched in PD cases in genome-wide association studies. Here we leverage recent whole-genome sequences from the Accelerating Medicines Partnership-Parkinson’s Disease (AMP-PD) and the Genome Aggregation (gnomAD) databases to characterize novel missense variants in LRRK2 and explore their relationships with known pathogenic and PD-linked missense variants. Using a computational prediction tool that successfully classifies known pathogenic LRRK2 missense variants, we describe an online web-based resource that catalogs characteristics of over 1200 LRRK2 missense variants of unknown significance. Novel high-pathogenicity scoring variants, some identified exclusively in PD cases, tightly cluster within the ROC-COR-Kinase domains. Structure–function predictions support that some of these variants exert gain-of-function effects with respect to LRRK2 kinase activity. In AMP-PD participants, all p.R1441G carriers (N = 89) are also carriers of the more common PD-linked variant p.M1646T. In addition, nearly all carriers of the PD-linked p.N2081D missense variant are also carriers of the LRRK2 PD-risk variant rs76904798. These results provide a compendium of LRRK2 missense variants and how they associate with one another. While the pathogenic p.G2019S variant is by far the most frequent high-pathogenicity scoring variant, our results suggest that ultra-rare missense variants may have an important cumulative impact in increasing the number of individuals with LRRK2-linked PD.

scholarly journals Systematic analysis of PINK1 variants of unknown significance shows intact mitophagy function for most variants

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Kai Yu Ma ◽  
Michiel R. Fokkens ◽  
Teus van Laar ◽  
Dineke S. Verbeek
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Missense Variant ◽  
Population Based ◽  
Loss Of Function ◽  
Systematic Analysis ◽  
Missense Variants ◽  
Variants Of Unknown Significance ◽  
Disease Case ◽  
Unknown Significance

AbstractPathogenic variants in PINK1 cause early-onset Parkinson’s disease. Although many PINK1 variants have been reported, the clinical significance is uncertain for the majority of them. To gain insights into the consequences of PINK1 missense variants in a systematic manner, we selected 50 PINK1 missense variants from patient- and population-wide databases and systematically classified them using Sherloc, a comprehensive framework for variant interpretation based on ACMG-AMP guidelines. We then performed functional experiments, including mitophagy and Parkin recruitment assays, to assess the downstream consequences of PINK1 variants. Analysis of PINK1 missense variants based on Sherloc showed that the patient databases over-annotate variants as likely pathogenic. Furthermore, our study shows that pathogenic PINK1 variants are most often linked to a loss-of-function for mitophagy and Parkin recruitment, while this is not observed for variants of unknown significance. In addition to the Sherloc framework, the added layer of evidence of our functional tests suggests a reclassification of 9/50 missense variants. In conclusion, we suggest the assessment of multiple layers of evidence, including functional data on top of available clinical and population-based data, to support the clinical classification of a variant and show that the presence of a missense variant in PINK1 in a Parkinson’s disease case does not automatically imply pathogenicity.

scholarly journals Genome‐wide association studies of LRRK2 modifiers of Parkinson's disease

2021 ◽  
Author(s):  
Dongbing Lai ◽  
Babak Alipanahi ◽  
Pierre Fontanillas ◽  
Tae‐Hwi Schwantes‐An ◽  
Jan Aasly ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Association Studies ◽  
Genome Wide Association ◽  
Genome Wide Association Studies ◽  
Genome Wide

scholarly journals Causal Association between Periodontitis and Parkinson’s Disease: A Bidirectional Mendelian Randomization Study

Genes ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 772
Author(s):  
João Botelho ◽  
Vanessa Machado ◽  
José João Mendes ◽  
Paulo Mascarenhas
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Instrumental Variables ◽  
Mendelian Randomization ◽  
Association Studies ◽  
European Ancestry ◽  
Genome Wide Association Studies ◽  
Nucleotide Polymorphisms ◽  
Genetic Liability ◽  
Bidirectional Association

The latest evidence revealed a possible association between periodontitis and Parkinson’s disease (PD). We explored the causal relationship of this bidirectional association through two-sample Mendelian randomization (MR) in European ancestry populations. To this end, we used openly accessible data of genome-wide association studies (GWAS) on periodontitis and PD. As instrumental variables for periodontitis, seventeen single-nucleotide polymorphisms (SNPs) from a GWAS of periodontitis (1817 periodontitis cases vs. 2215 controls) and eight non-overlapping SNPs of periodontitis from an additional GWAS for validation purposes. Instrumental variables to explore for the reverse causation included forty-five SNPs from a GWAS of PD (20,184 cases and 397,324 controls). Multiple approaches of MR were carried-out. There was no evidence of genetic liability of periodontitis being associated with a higher risk of PD (B = −0.0003, Standard Error [SE] 0.0003, p = 0.26). The eight independent SNPs (B = −0.0000, SE 0.0001, p = 0.99) validated this outcome. We also found no association of genetically primed PD towards periodontitis (B = −0.0001, SE 0.0001, p = 0.19). These MR study findings do not support a bidirectional causal genetic liability between periodontitis and PD. Further GWAS studies are needed to confirm the consistency of these results.

scholarly journals Combined knockout of Lrrk2 and Rab29 does not result in behavioral abnormalities in vivo

2020 ◽  
Author(s):  
Melissa Conti Mazza ◽  
Victoria Nguyen ◽  
Alexandra Beilina ◽  
Jinhui Ding ◽  
Mark R. Cookson
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Kinase Activity ◽  
Association Studies ◽  
Dopamine Neurons ◽  
Substantia Nigra Pars Compacta ◽  
Genome Wide Association Studies ◽  
Double Knockout ◽  
Knockout Mouse Model

AbstractCoding mutations in the LRRK2 gene, encoding for a large protein kinase, have been shown to cause familial Parkinson’s disease (PD). The immediate biological consequence of LRRK2 mutations is to increase kinase activity, leading to the suggestion that inhibition of this enzyme might be useful therapeutically to slow disease progression. Genome-wide association studies have identified the chromosomal loci around LRRK2 and one of its proposed substrates, RAB29, as contributors towards the lifetime risk of sporadic PD. Considering the evidence for interactions between LRRK2 and RAB29 on the genetic and protein levels, here we generated a double knockout mouse model and determined whether there are any consequences on brain function with aging. From a battery of motor and non-motor behavioral tests, we noted only that 18-24 month Rab29-/- and double (Lrrk2-/-/Rab29-/-) knockout mice had diminished locomotor behavior in open field compared to wildtype mice. However, no genotype differences were seen in number of substantia nigra pars compacta (SNc) dopamine neurons or in tyrosine hydroxylase levels in the SNc and striatum, which might reflect a PD-like pathology. These results suggest that depletion of both Lrrk2 and Rab29 is tolerated, at least in mice, and support that this pathway might be able to be safely targeted for therapeutics in humans.Significance statementGenetic variation in LRRK2 that result in elevated kinase activity can cause Parkinson’s disease (PD), suggesting LRRK2 inhibition as a therapeutic strategy. RAB29, a substrate of LRRK2, has also been associated with increased PD risk. Evidence exists for an interactive relationship between LRRK2 and RAB29. Mouse models lacking either LRRK2 or RAB29 do not show brain pathologies. We hypothesized that the loss of both targets would result in additive effects across in vivo and post-mortem assessments in aging mice. We found that loss of both LRRK2 and RAB29 did not result in significant behavioral deficits or dopamine neuron loss. This evidence suggests that chronic inhibition of this pathway should be tolerated clinically.

scholarly journals Gene4PD: A Comprehensive Genetic Database of Parkinson’s Disease

2021 ◽  
Vol 15 ◽  
Author(s):  
Bin Li ◽  
Guihu Zhao ◽  
Qiao Zhou ◽  
Yali Xie ◽  
Zheng Wang ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Neurodegenerative Disorder ◽  
Late Onset ◽  
Association Studies ◽  
Age At Onset ◽  
Genetic Data ◽  
Genome Wide Association Studies ◽  
Onset Age ◽  
Loss Of Function

Parkinson’s disease (PD) is a complex neurodegenerative disorder with a strong genetic component. A growing number of variants and genes have been reported to be associated with PD; however, there is no database that integrate different type of genetic data, and support analyzing of PD-associated genes (PAGs). By systematic review and curation of multiple lines of public studies, we integrate multiple layers of genetic data (rare variants and copy-number variants identified from patients with PD, associated variants identified from genome-wide association studies, differentially expressed genes, and differential DNA methylation genes) and age at onset in PD. We integrated five layers of genetic data (8302 terms) with different levels of evidences from more than 3,000 studies and prioritized 124 PAGs with strong or suggestive evidences. These PAGs were identified to be significantly interacted with each other and formed an interconnected functional network enriched in several functional pathways involved in PD, suggesting these genes may contribute to the pathogenesis of PD. Furthermore, we identified 10 genes were associated with a juvenile-onset (age ≤ 30 years), 11 genes were associated with an early-onset (age of 30–50 years), whereas another 10 genes were associated with a late-onset (age > 50 years). Notably, the AAOs of patients with loss of function variants in five genes were significantly lower than that of patients with deleterious missense variants, while patients with VPS13C (P = 0.01) was opposite. Finally, we developed an online database named Gene4PD (http://genemed.tech/gene4pd) which integrated published genetic data in PD, the PAGs, and 63 popular genomic data sources, as well as an online pipeline for prioritize risk variants in PD. In conclusion, Gene4PD provides researchers and clinicians comprehensive genetic knowledge and analytic platform for PD, and would also improve the understanding of pathogenesis in PD.

The role of α-synuclein in neurodegeneration — An update

2012 ◽  
Vol 3 (2) ◽  
Author(s):  
Kurt Jellinger
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Bound States ◽  
Physiological Function ◽  
Neuronal Degeneration ◽  
Association Studies ◽  
Common Mechanism ◽  
Genome Wide Association Studies ◽  
Potential Biomarker

AbstractGenetic, neuropathological and biochemical evidence implicates α-synuclein, a 140 amino acid presynaptic neuronal protein, in the pathogenesis of Parkinson’s disease and other neurodegenerative disorders. The aggregated protein inclusions mainly containing aberrant α-synuclein are widely accepted as morphological hallmarks of α-synucleinopathies, but their composition and location vary between disorders along with neuronal networks affected. α-Synuclein exists physiologically in both soluble and membran-bound states, in unstructured and α-helical conformations, respectively, while posttranslational modifications due to proteostatic deficits are involved in β-pleated aggregation resulting in formation of typical inclusions. The physiological function of α-synuclein and its role linked to neurodegeneration, however, are incompletely understood. Soluble oligomeric, not fully fibrillar α-synuclein is thought to be neurotoxic, main targets might be the synapse, axons and glia. The effects of aberrant α-synuclein include alterations of calcium homeostasis, mitochondrial dysfunction, oxidative and nitric injuries, cytoskeletal effects, and neuroinflammation. Proteasomal dysfunction might be a common mechanism in the pathogenesis of neuronal degeneration in α-synucleinopathies. However, how α-synuclein induces neurodegeneration remains elusive as its physiological function. Genome wide association studies demonstrated the important role for genetic variants of the SNCA gene encoding α-synuclein in the etiology of Parkinson’s disease, possibly through effects on oxidation, mitochondria, autophagy, and lysosomal function. The neuropathology of synucleinopathies and the role of α-synuclein as a potential biomarker are briefly summarized. Although animal models provided new insights into the pathogenesis of Parkinson disease and multiple system atrophy, most of them do not adequately reproduce the cardinal features of these disorders. Emerging evidence, in addition to synergistic interactions of α-synuclein with various pathogenic proteins, suggests that prionlike induction and seeding of α-synuclein could lead to the spread of the pathology and disease progression. Intervention in the early aggregation pathway, aberrant cellular effects, or secretion of α-synuclein might be targets for neuroprotection and disease-modifying therapy.

Gene Co-Expression Network Analysis Implicates microRNA Processing in Parkinson’s Disease Pathogenesis

2018 ◽  
Vol 18 (4) ◽  
pp. 191-199 ◽  
Author(s):  
Jason A. Chen
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Network Analysis ◽  
Statistical Power ◽  
Association Studies ◽  
Model Systems ◽  
Specific Cell ◽  
Genome Wide Association Studies ◽  
Microrna Processing ◽  
Highly Correlated

Background: Recent advances in genetics have provided insights into important inherited causes of Parkinson’s disease (PD), but the underlying biological mechanisms are still incompletely understood. Gene expression studies have pointed toward the dysregulation of neuroinflammation, mitochondrial function, and protein degradation pathways. Objective: We aimed to identify groups of dysregulated genes in PD. Methods: In order to increase statistical power and control for potential confounders, we re-analyzed transcriptomic data from PD patients and model systems, integrating additional genomic data using a systems biology approach. Using weighted gene co-expression network analysis, we partitioned genes into co-expressed modules. Results: One co-expression module, M13, had an expression trajectory that was highly correlated with PD, was not characterized by any specific cell type markers, and was enriched in PD genes identified by genome-wide association studies. Genes within M13 seemed to be related to global microRNA biogenesis, and DICER1 and AGO3 were highly connected within the module. The NUCKS1 gene, previously identified as part of the PARK16 locus, was also a hub gene within M13. Conclusion: These results suggest that microRNA processing and function may play a role in the pathogenesis of PD, and thus may represent a useful target for future drug development.

scholarly journals LRRK2 links genetic and sporadic Parkinson's disease

2019 ◽  
Vol 47 (2) ◽  
pp. 651-661 ◽  
Author(s):  
Jillian H. Kluss ◽  
Adamantios Mamais ◽  
Mark R. Cookson
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Kinase Inhibitors ◽  
Association Studies ◽  
Neuronal Cell Death ◽  
Neuronal Cell ◽  
Vesicular Trafficking ◽  
Common Mechanism ◽  
Genome Wide Association Studies ◽  
Functional Studies

Abstract The past two decades in research has revealed the importance of leucine-rich repeat kinase 2 (LRRK2) in both monogenic and sporadic forms of Parkinson's disease (PD). In families, mutations in LRRK2 can cause PD with age-dependent but variable penetrance and genome-wide association studies have found variants of the gene that are risk factors for sporadic PD. Functional studies have suggested that the common mechanism that links all disease-associated variants is that they increase LRRK2 kinase activity, albeit in different ways. Here, we will discuss the roles of LRRK2 in areas of inflammation and vesicular trafficking in the context of monogenic and sporadic PD. We will also provide a hypothetical model that links inflammation and vesicular trafficking together in an effort to outline how these pathways might interact and eventually lead to neuronal cell death. We will also highlight the translational potential of LRRK2-specific kinase inhibitors for the treatment of PD.

scholarly journals Polymorphisms of ACMSD-TMEM163, MCCC1, and BCKDK-STX1B Are Not Associated with Parkinson’s Disease in Taiwan

2019 ◽  
Vol 2019 ◽  
pp. 1-6 ◽  
Author(s):  
Kuo-Hsuan Chang ◽  
Chiung-Mei Chen ◽  
Yi-Chun Chen ◽  
Hon-Chung Fung ◽  
Yih-Ru Wu
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Amino Acid ◽  
Genetic Variants ◽  
Transmembrane Protein ◽  
Association Studies ◽  
Genome Wide Association ◽  
Genome Wide Association Studies ◽  
Amino Acid Catabolism ◽  
Genome Wide

Previous genome-wide association studies in Caucasian populations suggest that genetic loci in amino acid catabolism may be associated with Parkinson’s disease (PD). However, these genetic disease associations were limitedly reported in Asian populations. Herein, we investigated the effect of top three PD-associated genetic variants related to amino acid catabolism in Caucasians listed on the top risk loci identified by meta-analysis of genome-wide association studies in PDGene database, including aminocarboxymuconate-semialdehyde decarboxylase- (ACMSD-) transmembrane protein 163 (TMEM163) rs6430538, methylcrotonyl-CoA carboxylase 1 (MCCC1) rs12637471, and branched-chain ketoacid dehydrogenase kinase- (BCKDK-) syntaxin 1B (STX1B) rs14235, by genotyping 599 Taiwanese patients with PD and 598 age-matched control subjects. PD patients demonstrate similar allelic and genotypic frequencies in all tested genetic variants. These ethnic discrepancies of genetic variants suggest a distinct genetic background of amino acid catabolism between Taiwanese and Caucasian PD patients.

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