References of "Zimprich, Alexander"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailThe Interaction between HLA-DRB1 and Smoking in Parkinson's Disease Revisited
Domenighetti, Cloé; Douillard, Venceslas; Sugier, Pierre-Emmanuel et al

in Movement Disorders (2022)

Abstract Background Two studies that examined the interaction between HLA-DRB1 and smoking in Parkinson's disease (PD) yielded findings in opposite directions. Objective To perform a large-scale ... [more ▼]

Abstract Background Two studies that examined the interaction between HLA-DRB1 and smoking in Parkinson's disease (PD) yielded findings in opposite directions. Objective To perform a large-scale independent replication of the HLA-DRB1 × smoking interaction. Methods We genotyped 182 single nucleotide polymorphism (SNPs) associated with smoking initiation in 12 424 cases and 9480 controls to perform a Mendelian randomization (MR) analysis in strata defined by HLA-DRB1. Results At the amino acid level, a valine at position 11 (V11) in HLA-DRB1 displayed the strongest association with PD. MR showed an inverse association between genetically predicted smoking initiation and PD only in absence of V11 (odds ratio, 0.74, 95 confidence interval, 0.59–0.93, PInteraction = 0.028). In silico predictions of the influence of V11 and smoking-induced modifications of α-synuclein on binding affinity showed findings consistent with this interaction pattern. Conclusions Despite being one of the most robust findings in PD research, the mechanisms underlying the inverse association between smoking and PD remain unknown. Our findings may help better understand this association. © 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society [less ▲]

Detailed reference viewed: 66 (0 UL)
Full Text
Peer Reviewed
See detailGenome-wide Association and Meta-analysis of Age-at-Onset in Parkinson Disease: Evidence From COURAGE-PD Consortium 10.1212/WNL.0000000000200699
Grover, Sandeep; Ashwin, Ashok Kumar Sreelatha; Pihlstrom, Lasse et al

in Neurology (2022)

Background and Objectives: Considerable heterogeneity exists in the literature concerning genetic determinants of the age of onset (AAO) of Parkinson\textquoterights disease (PD), which could be ... [more ▼]

Background and Objectives: Considerable heterogeneity exists in the literature concerning genetic determinants of the age of onset (AAO) of Parkinson\textquoterights disease (PD), which could be attributed to lack of well-powered replication cohorts. The previous largest GWAS identified SNCA and TMEM175 loci on chromosome (Chr) 4 with a significant influence on AAO of PD, these have not been independently replicated. The present study aims to conduct a meta-analysis of GWAS of PD AAO and validate previously observed findings in worldwide populations.Methods: A meta-analysis was performed on PD AAO GWAS of 30 populations of predominantly European ancestry from the Comprehensive Unbiased Risk Factor Assessment for Genetics and Environment in Parkinson\textquoterights Disease (COURAGE-PD) consortium. This was followed up by combining our study with the largest publicly available European ancestry dataset compiled by the International Parkinson disease Genomics Consortium (IPDGC).Results: The COURAGE-PD included a cohort of 8,535 patients with PD (91.9\%: Europeans, 9.1\%: East-Asians). The average AAO in the COURAGE-PD dataset was 58.9 years (SD=11.6), with an under-representation of females (40.2\%). The heritability estimate for AAO in COURAGE-PD was 0.083 (SE=0.057). None of the loci reached genome-wide significance (P\<5x10-8). Nevertheless, the COURAGE-PD dataset confirmed the role of the previously published TMEM175 variant as genetic determinant of AAO of PD with Bonferroni-corrected nominal levels of significance (P\<0.025): (rs34311866:β(SE)COURAGE=0.477(0.203), PCOURAGE=0.0185). The subsequent meta-analysis of COURAGE-PD and IPDGC datasets (Ntotal=25,950) led to the identification of two genome-wide significant association signals on Chr 4, including the previously reported SNCA locus (rs983361:β(SE)COURAGE+IPDGC=0.720(0.122), PCOURAGE+IPDGC=3.13x10-9) and a novel BST1 locus (rs4698412:β(SE)COURAGE+IPDGC=-0.526(0.096), PCOURAGE+IPDGC=4.41x10-8).Discussion: Our study further refines the genetic architecture of Chr 4 underlying the AAO of the PD phenotype through the identification of BST1 as a novel AAO PD locus. These findings open a new direction for the development of treatments to delay the onset of PD. [less ▲]

Detailed reference viewed: 23 (0 UL)
Full Text
Peer Reviewed
See detailDairy Intake and Parkinson's Disease: A Mendelian Randomization Study
Domenighetti, Cloé; Sugier, Pierre-Emmanuel; Ashok Kumar Sreelatha, Ashwin et al

in Movement Disorders (2022)

Abstract Background Previous prospective studies highlighted dairy intake as a risk factor for Parkinson's disease (PD), particularly in men. It is unclear whether this association is causal or explained ... [more ▼]

Abstract Background Previous prospective studies highlighted dairy intake as a risk factor for Parkinson's disease (PD), particularly in men. It is unclear whether this association is causal or explained by reverse causation or confounding. Objective The aim is to examine the association between genetically predicted dairy intake and PD using two-sample Mendelian randomization (MR). Methods We genotyped a well-established instrumental variable for dairy intake located in the lactase gene (rs4988235) within the Courage-PD consortium (23 studies; 9823 patients and 8376 controls of European ancestry). Results Based on a dominant model, there was an association between genetic predisposition toward higher dairy intake and PD (odds ratio [OR] per one serving per day = 1.70, 95 confidence interval = 1.12–2.60, P = 0.013) that was restricted to men (OR = 2.50 [1.37–4.56], P = 0.003; P-difference with women = 0.029). Conclusions Using MR, our findings provide further support for a causal relationship between dairy intake and higher PD risk, not biased by confounding or reverse causation. Further studies are needed to elucidate the underlying mechanisms. © 2022 International Parkinson and Movement Disorder Society [less ▲]

Detailed reference viewed: 62 (4 UL)
Full Text
Peer Reviewed
See detailMendelian randomization study of smoking, alcohol, and coffee drinking in relation to Parkinso's disease
Domenighetti, Cloe; Sugier, Pierre Emmanuel; Sreelatha, Ashwin Ashok Kumar et al

in Journal of Parkinson's Disease (2021)

Background:Previous studies showed that lifestyle behaviors (cigarette smoking, alcohol, coffee) are inversely associated with Parkinson’s disease (PD). The prodromal phase of PD raises the possibility ... [more ▼]

Background:Previous studies showed that lifestyle behaviors (cigarette smoking, alcohol, coffee) are inversely associated with Parkinson’s disease (PD). The prodromal phase of PD raises the possibility that these associations may be explained by reverse causation. Objective:To examine associations of lifestyle behaviors with PD using two-sample Mendelian randomisation (MR) and the potential for survival and incidence-prevalence biases. Methods:We used summary statistics from publicly available studies to estimate the association of genetic polymorphisms with lifestyle behaviors, and from Courage-PD (7,369 cases, 7,018 controls; European ancestry) to estimate the association of these variants with PD. We used the inverse-variance weighted method to compute odds ratios (ORIVW) of PD and 95%confidence intervals (CI). Significance was determined using a Bonferroni-corrected significance threshold (p = 0.017). Results:We found a significant inverse association between smoking initiation and PD (ORIVW per 1-SD increase in the prevalence of ever smoking = 0.74, 95%CI = 0.60–0.93, p = 0.009) without significant directional pleiotropy. Associations in participants ≤67 years old and cases with disease duration ≤7 years were of a similar size. No significant associations were observed for alcohol and coffee drinking. In reverse MR, genetic liability toward PD was not associated with smoking or coffee drinking but was positively associated with alcohol drinking. Conclusion:Our findings are in favor of an inverse association between smoking and PD that is not explained by reverse causation, confounding, and survival or incidence-prevalence biases. Genetic liability toward PD was positively associated with alcohol drinking. Conclusions on the association of alcohol and coffee drinking with PD are hampered by insufficient statistical power. [less ▲]

Detailed reference viewed: 35 (5 UL)
Full Text
Peer Reviewed
See detailMitochondrial damage-associated inflammation highlights biomarkers in PRKN/PINK1 parkinsonism
Borsche, Max; Koenig, Inke; Delcambre, Sylvie UL et al

in Brain: a Journal of Neurology (2020)

There is increasing evidence for a role of inflammation in Parkinson’s disease. Recent research in murine models suggests that parkin and PINK1 deficiency leads to impaired mitophagy, which causes the ... [more ▼]

There is increasing evidence for a role of inflammation in Parkinson’s disease. Recent research in murine models suggests that parkin and PINK1 deficiency leads to impaired mitophagy, which causes the release of mitochondrial DNA (mtDNA), thereby triggering inflammation. Specifically, the CGAS (cyclic GMP-AMP synthase)-STING (stimulator of interferon genes) pathway mitigates activation of the innate immune system, quantifiable as increased interleukin-6 (IL6) levels. However, the role of IL6 and circulating cell-free mtDNA in unaffected and affected individuals harbouring mutations in PRKN/PINK1 and idiopathic Parkinson’s disease patients remain elusive. We investigated IL6, C-reactive protein, and circulating cell-free mtDNA in serum of 245 participants in two cohorts from tertiary movement disorder centres. We performed a hypothesis-driven rank-based statistical approach adjusting for multiple testing. We detected (i) elevated IL6 levels in patients with biallelic PRKN/PINK1 mutations compared to healthy control subjects in a German cohort, supporting the concept of a role for inflammation in PRKN/PINK1-linked Parkinson’s disease. In addition, the comparison of patients with biallelic and heterozygous mutations in PRKN/PINK1 suggests a gene dosage effect. The differences in IL6 levels were validated in a second independent Italian cohort; (ii) a correlation between IL6 levels and disease duration in carriers of PRKN/PINK1 mutations, while no such association was observed for idiopathic Parkinson’s disease patients. These results highlight the potential of IL6 as progression marker in Parkinson’s disease due to PRKN/PINK1 mutations; (iii) increased circulating cell-free mtDNA serum levels in both patients with biallelic or with heterozygous PRKN/PINK1 mutations compared to idiopathic Parkinson’s disease, which is in line with previous findings in murine models. By contrast, circulating cell-free mtDNA concentrations in unaffected heterozygous carriers of PRKN/PINK1 mutations were comparable to control levels; and (iv) that circulating cell-free mtDNA levels have good predictive potential to discriminate between idiopathic Parkinson’s disease and Parkinson’s disease linked to heterozygous PRKN/PINK1 mutations, providing functional evidence for a role of heterozygous mutations in PRKN or PINK1 as Parkinson’s disease risk factor. Taken together, our study further implicates inflammation due to impaired mitophagy and subsequent mtDNA release in the pathogenesis of PRKN/PINK1-linked Parkinson’s disease. In individuals carrying mutations in PRKN/PINK1, IL6 and circulating cell-free mtDNA levels may serve as markers of Parkinson’s disease state and progression, respectively. Finally, our study suggests that targeting the immune system with anti-inflammatory medication holds the potential to influence the disease course of Parkinson’s disease, at least in this subset of patients. [less ▲]

Detailed reference viewed: 109 (8 UL)
Full Text
Peer Reviewed
See detailReply: No evidence for rare TRAP1 mutations influencing the risk of idiopathic Parkinson’s disease
Fitzgerald, Julia C.; Zimprich, Alexander; Bobbili, Dheeraj Reddy UL et al

in Brain : A Journal of Neurology (2018)

Sir, In their letter in this issue, Gaare and colleagues (2018) state that TRAP1 may not be a Parkinson’s disease gene because of lack of genetic association. In response, we welcome their data analyses ... [more ▼]

Sir, In their letter in this issue, Gaare and colleagues (2018) state that TRAP1 may not be a Parkinson’s disease gene because of lack of genetic association. In response, we welcome their data analyses and we welcome any further genetic analyses of TRAP1 variants in additional Parkinson’s disease genetic datasets, including the reanalysis of open access datasets such as the Parkinson’s Progressive Markers Initiative (PPMI). Our point of view is that TRAP1 is an interesting effector protein that our study unequivocally showed is relevant to Parkinson’s disease signaling in the context of mitochondrial regulation. Furthermore, the overall contribution of TRAP1 genetic variants to Parkinson’s disease was not the focus of our recent paper in Brain (Fitzgerald et al., 2017). [less ▲]

Detailed reference viewed: 225 (27 UL)
Full Text
Peer Reviewed
See detailMetformin reverses TRAP1 mutation-associated alterations in mitochondrial function in Parkinson's disease
Fitzgerald, Julia C.; Zimprich, Alexander; Carvajal-Berrio, Daniel A. et al

in Brain : A Journal of Neurology (2017), 140(9), 2444-2459

The mitochondrial proteins TRAP1 and HtrA2 have previously been shown to be phosphorylated in the presence of the Parkinson’s disease kinase PINK1 but the downstream signaling is unclear. HtrA2 and PINK1 ... [more ▼]

The mitochondrial proteins TRAP1 and HtrA2 have previously been shown to be phosphorylated in the presence of the Parkinson’s disease kinase PINK1 but the downstream signaling is unclear. HtrA2 and PINK1 loss of function causes parkinsonism in humans and animals. Here, we identified TRAP1 as an interactor of HtrA2 using an unbiased mass spectrometry approach. In our human cell models, TRAP1 overexpression is protective, rescuing HtrA2 and PINK1-associated mitochondrial dysfunction and suggesting that TRAP1 acts downstream of HtrA2 and PINK1. HtrA2 regulates TRAP1 protein levels, but TRAP1 is not a direct target of HtrA2 protease activity. Following genetic screening of Parkinson’s disease patients and healthy controls, we also report the first TRAP1 mutation leading to complete loss of functional protein in a patient with late onset Parkinson’s disease. Analysis of fibroblasts derived from the patient reveal that oxygen consumption, ATP output and reactive oxygen species are increased compared to healthy individuals. This is coupled with an increased pool of free NADH, increased mitochondrial biogenesis, triggering of the mitochondrial unfolded protein response, loss of mitochondrial membrane potential and sensitivity to mitochondrial removal and apoptosis. These data highlight the role of TRAP1 in the regulation of energy metabolism and mitochondrial quality control. Interestingly, the diabetes drug metformin reverses mutation-associated alterations on energy metabolism, mitochondrial biogenesis and restores mitochondrial membrane potential. In summary, our data show that TRAP1 acts downstream of PINK1 and HtrA2 for mitochondrial fine tuning, whereas TRAP1 loss of function leads to reduced control of energy metabolism, ultimately impacting mitochondrial membrane potential. These findings offer new insight into mitochondrial pathologies in Parkinson’s disease and provide new prospects for targeted therapies. [less ▲]

Detailed reference viewed: 289 (34 UL)
Full Text
Peer Reviewed
See detailA multi-centre clinico-genetic analysis of the VPS35 gene in Parkinson disease indicates reduced penetrance for disease-associated variants.
Sharma, Manu; Ioannidis, John P. A.; Aasly, Jan O. et al

in Journal of medical genetics (2012), 49(11), 721-6

BACKGROUND: Two recent studies identified a mutation (p.Asp620Asn) in the vacuolar protein sorting 35 gene as a cause for an autosomal dominant form of Parkinson disease . Although additional missense ... [more ▼]

BACKGROUND: Two recent studies identified a mutation (p.Asp620Asn) in the vacuolar protein sorting 35 gene as a cause for an autosomal dominant form of Parkinson disease . Although additional missense variants were described, their pathogenic role yet remains inconclusive. METHODS AND RESULTS: We performed the largest multi-center study to ascertain the frequency and pathogenicity of the reported vacuolar protein sorting 35 gene variants in more than 15,000 individuals worldwide. p.Asp620Asn was detected in 5 familial and 2 sporadic PD cases and not in healthy controls, p.Leu774Met in 6 cases and 1 control, p.Gly51Ser in 3 cases and 2 controls. Overall analyses did not reveal any significant increased risk for p.Leu774Met and p.Gly51Ser in our cohort. CONCLUSIONS: Our study apart from identifying the p.Asp620Asn variant in familial cases also identified it in idiopathic Parkinson disease cases, and thus provides genetic evidence for a role of p.Asp620Asn in Parkinson disease in different populations worldwide. [less ▲]

Detailed reference viewed: 130 (0 UL)
Peer Reviewed
See detailThe DRD2 TaqIA polymorphism and demand of dopaminergic medication in Parkinson's disease.
Paus, Sebastian; Grünewald, Anne UL; Klein, Christine UL et al

in Movement Disorders (2008), 23(4), 599-602

Previous studies have demonstrated that the TaqIA polymorphism of the D2 dopamine receptor gene (DRD2) is associated with response to dopaminergic and antidopaminergic treatment in Parkinson's disease (PD ... [more ▼]

Previous studies have demonstrated that the TaqIA polymorphism of the D2 dopamine receptor gene (DRD2) is associated with response to dopaminergic and antidopaminergic treatment in Parkinson's disease (PD) and schizophrenia, respectively. We tested whether the TaqIA genotype in PD is responsible for demand of dopaminergic medication, measured in total dopaminergic load per year of disease, in a large scale association study based on the gene bank of the German Competence Network on Parkinson's disease. Regression analysis yielded no significant differences between the TaqIA genotypes. We conclude that the DRD2 TaqIA polymorphism alone has no pivotal role for interindividual variability of dopaminergic requirement in PD. We propose a practicable system of measuring dopaminergic treatment for future pharmacogenetic studies in PD. [less ▲]

Detailed reference viewed: 44 (3 UL)