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See detailBenchmarking Low-Frequency Variant Calling With Long-Read Data on Mitochondrial DNA
Lüth, Theresa; Schaake, Susen; Grünewald, Anne UL et al

in Frontiers in Genetics (2022), 13

Background: Sequencing quality has improved over the last decade for long-reads, allowing for more accurate detection of somatic low-frequency variants. In this study, we used mixtures of mitochondrial ... [more ▼]

Background: Sequencing quality has improved over the last decade for long-reads, allowing for more accurate detection of somatic low-frequency variants. In this study, we used mixtures of mitochondrial samples with different haplogroups (i.e., a specific set of mitochondrial variants) to investigate the applicability of nanopore sequencing for low-frequency single nucleotide variant detection.Methods: We investigated the impact of base-calling, alignment/mapping, quality control steps, and variant calling by comparing the results to a previously derived short-read gold standard generated on the Illumina NextSeq. For nanopore sequencing, six mixtures of four different haplotypes were prepared, allowing us to reliably check for expected variants at the predefined 5%, 2%, and 1% mixture levels. We used two different versions of Guppy for base-calling, two aligners (i.e., Minimap2 and Ngmlr), and three variant callers (i.e., Mutserve2, Freebayes, and Nanopanel2) to compare low-frequency variants. We used F<sub>1</sub> score measurements to assess the performance of variant calling.Results: We observed a mean read length of 11 kb and a mean overall read quality of 15. Ngmlr showed not only higher F<sub>1</sub> scores but also higher allele frequencies (AF) of false-positive calls across the mixtures (mean F<sub>1</sub> score = 0.83; false-positive allele frequencies < 0.17) compared to Minimap2 (mean F<sub>1</sub> score = 0.82; false-positive AF < 0.06). Mutserve2 had the highest F<sub>1</sub> scores (5% level: F<sub>1</sub> score >0.99, 2% level: F<sub>1</sub> score >0.54, and 1% level: F<sub>1</sub> score >0.70) across all callers and mixture levels.Conclusion: We here present the benchmarking for low-frequency variant calling with nanopore sequencing by identifying current limitations. [less ▲]

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See detailMitochondrial DNA heteroplasmy distinguishes disease manifestation in PINK1- and PRKN-linked Parkinson's disease 2022.05.17.22275087
Trinh, Joanne; Hicks, Andrew A.; Koenig, Inke R. et al

E-print/Working paper (2022)

Biallelic mutations in PINK1 and PRKN cause recessively inherited Parkinson's disease (PD). Though some studies suggest that PINK1/PRKN monoallelic mutations may not contribute to risk, deep phenotyping ... [more ▼]

Biallelic mutations in PINK1 and PRKN cause recessively inherited Parkinson's disease (PD). Though some studies suggest that PINK1/PRKN monoallelic mutations may not contribute to risk, deep phenotyping assessment showed that PINK1 or PRKN monoallelic pathogenic variants were at a significantly higher rate in PD compared to controls. Given the established role of PINK1 and Parkin in regulating mitochondrial dynamics, we explored mitochondrial DNA (mtDNA) integrity and inflammation as potential disease modifiers in carriers of mutations in these genes. MtDNA integrity, global gene expression and serum cytokine levels were investigated in a large collection of biallelic (n=84) and monoallelic (n=170) carriers of PINK1/PRKN mutations, iPD patients (n=67) and controls (n=90). Affected and unaffected PINK1/PRKN monoallelic mutation carriers can be distinguished by heteroplasmic mtDNA variant load (AUC=0.83, CI:0.74-0.93). Biallelic PINK1/PRKN mutation carriers harbor more heteroplasmic mtDNA variants in blood (p=0.0006, Z=3.63) compared to monoallelic mutation carriers. This enrichment was confirmed in iPSC-derived and postmortem midbrain neurons from biallelic PRKN-PD patients. Lastly, the heteroplasmic mtDNA variant load was found to correlate with IL6 levels in PINK1/PRKN mutation carriers (r=0.57, p=0.0074). PINK1/PRKN mutations predispose individuals to mtDNA variant accumulation in a dose- and disease-dependent manner. MtDNA variant load over time is a potential marker of disease manifestation in PINK1/PRKN mutation carriers.Competing Interest StatementThe authors have declared no competing interest.Funding StatementThe authors wish to thank the many patients and their families who volunteered, and the efforts of the many clinical teams involved. Funding has been obtained from the German Research Foundation (ProtectMove; FOR 2488, GR 3731/5-1; SE 2608/2-1; KO 2250/7-1), the Luxembourg National Research Fund in the ATTRACT (Model-IPD, FNR9631103), NCER-PD (FNR11264123) and INTER programmes (ProtectMove, FNR11250962; MiRisk-PD, C17/BM/11676395, NB 4328/2-1), the BMBF (MitoPD), the Hermann and Lilly Schilling Foundation, the European Community (SysMedPD), the Canadian Institutes of Health Research (CIHR), Peter and Traudl Engelhorn Foundation. Initial studies in Tunisia on familial parkinsonism were in collaboration with Lefkos Middleton, Rachel Gibson, and the GlaxoSmithKline PD Programme Team (2002-2005). We would like to thank Dr Helen Tuppen from the Welcome Trust Centre for Mitochondrial Research, Newcastle University, UK for providing us with the plasmid p7D1. Moreover, this project was supported by the high throughput/high content screening platform and HPC facility at the Luxembourg Centre for Systems Biomedicine, and the University of Luxembourg.Author DeclarationsI confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.YesThe details of the IRB/oversight body that provided approval or exemption for the research described are given below:University of Lubeck Ethics CommitteeI confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.YesI understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable.YesAll data produced in the present study are available upon reasonable request to the authors [less ▲]

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See detailmGlu3 Metabotropic Glutamate Receptors as a Target for the Treatment of Absence Epilepsy: Preclinical and Human Genetics Data
Celli, Roberta; Striano, Pasquale; Citraro, Rita et al

in Current Neuropharmacology (2022)

Abstract: Background: Previous studies suggest that different metabotropic glutamate (mGlu) receptor subtypes are potential drug targets for treating absence epilepsy. However, no information is available ... [more ▼]

Abstract: Background: Previous studies suggest that different metabotropic glutamate (mGlu) receptor subtypes are potential drug targets for treating absence epilepsy. However, no information is available on mGlu3 receptors. Objective: To examine whether (i) changes of mGlu3 receptor expression/signaling are found in the somatosensory cortex and thalamus of WAG/Rij rats developing spontaneous absence seizures; (ii) selective activation of mGlu3 receptors with LY2794193 affects the number and duration of spike- wave discharges (SWDs) in WAG/Rij rats; and (iii) a genetic variant of GRM3 (encoding the mGlu3 receptor) is associated with absence epilepsy. Methods: Animals: immunoblot analysis of mGlu3 receptors, GAT-1, GLAST, and GLT-1; real- time PCR analysis of mGlu3 mRNA levels; assessment of mGlu3 receptor signaling; EEG analysis of SWDs; assessment of depressive-like behavior. Humans: search for GRM3 and GRM5 missense variants in 196 patients with absence epilepsy or other Idiopathic Generalized Epilepsy (IGE)/ Genetic Generalized Epilepsy (GGE) and 125,748 controls. Results: mGlu3 protein levels and mGlu3-mediated inhibition of cAMP formation were reduced in the thalamus and somatosensory cortex of pre-symptomatic (25-27 days old) and symptomatic (6-7 months old) WAG/Rij rats compared to age-matched controls. Treatment with LY2794193 (1 or 10 mg/kg, i.p.) reduced absence seizures and depressive-like behavior in WAG/Rij rats. LY2794193 also enhanced GAT1, GLAST, and GLT-1 protein levels in the thalamus and somatosensory cortex. GRM3 and GRM5 gene variants did not differ between epileptic patients and controls. Conclusion: We suggest that mGlu3 receptors modulate the activity of the cortico-thalamo-cortical circuit underlying SWDs and that selective mGlu3 receptor agonists are promising candidate drugs for absence epilepsy treatment. [less ▲]

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See detailSingle-cell sequencing of human midbrain reveals glial activation and a Parkinson-specific neuronal state.
Smajic, Semra UL; Prada-Medina, Cesar A.; Landoulsi, Zied UL et al

in Brain : a journal of neurology (2022), 145(3), 964-978

Idiopathic Parkinson's disease is characterized by a progressive loss of dopaminergic neurons, but the exact disease etiology remains largely unknown. To date, Parkinson's disease research has mainly ... [more ▼]

Idiopathic Parkinson's disease is characterized by a progressive loss of dopaminergic neurons, but the exact disease etiology remains largely unknown. To date, Parkinson's disease research has mainly focused on nigral dopaminergic neurons, although recent studies suggest disease-related changes also in non-neuronal cells and in midbrain regions beyond the substantia nigra. While there is some evidence for glial involvement in Parkinson's disease, the molecular mechanisms remain poorly understood. The aim of this study was to characterize the contribution of all cell types of the midbrain to Parkinson's disease pathology by single-nuclei RNA sequencing and to assess the cell type-specific risk for Parkinson's disease employing the latest genome-wide association study. We profiled >41 000 single-nuclei transcriptomes of postmortem midbrain from six idiopathic Parkinson's disease patients and five age-/sex-matched controls. To validate our findings in a spatial context, we utilized immunolabeling of the same tissues. Moreover, we analyzed Parkinson's disease-associated risk enrichment in genes with cell type-specific expression patterns. We discovered a neuronal cell cluster characterized by CADPS2 overexpression and low TH levels, which was exclusively present in IPD midbrains. Validation analyses in laser-microdissected neurons suggest that this cluster represents dysfunctional dopaminergic neurons. With regard to glial cells, we observed an increase in nigral microglia in Parkinson's disease patients. Moreover, nigral idiopathic Parkinson's disease microglia were more amoeboid, indicating an activated state. We also discovered a reduction in idiopathic Parkinson's disease oligodendrocyte numbers with the remaining cells being characterized by a stress-induced upregulation of S100B. Parkinson's disease risk variants were associated with glia- and neuron-specific gene expression patterns in idiopathic Parkinson's disease cases. Furthermore, astrocytes and microglia presented idiopathic Parkinson's disease-specific cell proliferation and dysregulation of genes related to unfolded protein response and cytokine signaling. While reactive patient astrocytes showed CD44 overexpression, idiopathic Parkinson's disease-microglia revealed a pro-inflammatory trajectory characterized by elevated levels of IL1B, GPNMB, and HSP90AA1. Taken together, we generated the first single-nuclei RNA sequencing dataset from the idiopathic Parkinson's disease midbrain, which highlights a disease-specific neuronal cell cluster as well as 'pan-glial' activation as a central mechanism in the pathology of the movement disorder. This finding warrants further research into inflammatory signaling and immunomodulatory treatments in Parkinson's disease. [less ▲]

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See detailCNV-ClinViewer: Enhancing the clinical interpretation of large copy-number variants online
Macnee, Marie; Perez-Palma, Eduardo; Brünger, Tobias et al

E-print/Working paper (2022)

Purpose Large copy number variants (CNVs) can cause a heterogeneous spectrum of rare and severe disorders. However, most CNVs are benign and are part of natural variation in human genomes. CNV ... [more ▼]

Purpose Large copy number variants (CNVs) can cause a heterogeneous spectrum of rare and severe disorders. However, most CNVs are benign and are part of natural variation in human genomes. CNV pathogenicity classification, genotype-phenotype analyses, and therapeutic target identification are challenging and time-consuming tasks that require the integration and analysis of information from multiple scattered sources by experts. Methods We developed a web-application combining >250,000 patient and population CNVs together with a large set of biomedical annotations and provide tools for CNV classification based on ACMG/ClinGen guidelines and gene-set enrichment analyses. Results Here, we introduce the CNV-ClinViewer (https://cnv-ClinViewer.broadinstitute.org), an open-source web-application for clinical evaluation and visual exploration of CNVs. The application enables real-time interactive exploration of large CNV datasets in a user-friendly designed interface. Conclusion Overall, this resource facilitates semi-automated clinical CNV interpretation and genomic loci exploration and, in combination with clinical judgment, enables clinicians and researchers to formulate novel hypotheses and guide their decision-making process. Subsequently, the CNV-ClinViewer enhances for clinical investigators patient care and for basic scientists translational genomic research. [less ▲]

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See detailConserved patterns across ion channels correlate with variant pathogenicity and clinical phenotypes 2022.03.23.485339
Brünger, Tobias; Perez-Palma, Eduardo; Montanucci, Ludovica et al

E-print/Working paper (2022)

Clinically identified genetic variants in ion channels can be benign or cause disease by increasing or decreasing the protein function. Consequently, therapeutic decision-making is challenging without ... [more ▼]

Clinically identified genetic variants in ion channels can be benign or cause disease by increasing or decreasing the protein function. Consequently, therapeutic decision-making is challenging without molecular testing of each variant. Our biophysical knowledge of ion channel structures and function is just emerging, and it is currently not well understood which amino acid residues cause disease when mutated.We sought to systematically identify biological properties associated with variant pathogenicity across all major voltage and ligand-gated ion channel families. We collected and curated 3,049 pathogenic variants from hundreds of neurodevelopmental and other disorders and 12,546 population variants for 30 ion channel or channel subunits for which a high-quality protein structure was available. Using a wide range of bioinformatics approaches, we computed 163 structural features and tested them for pathogenic variant enrichment. We developed a novel 3D spatial distance scoring approach that enables comparisons of pathogenic and population variant distribution across protein structures.We discovered and independently replicated that several pore residue properties and proximity to the pore axis were most significantly enriched for pathogenic variants compared to population variants. Using our novel 3D scoring approach, we showed that the strongest pathogenic variant enrichment was observed for pore-lining residues and alpha-helix residues within 5 A distance from the pore axis center and not involved in gating. Within the subset of residues located at the pore, the hydrophobicity of the pore was the feature most strongly associated with variant pathogenicity. We also found an association between the identified properties and both clinical phenotypes and fucntional in vitro assays for voltage-gated sodium channels (SCN1A, SCN2A, SCN8A) and N-methyl-D-aspartate (NMDA) receptor (GRIN1, GRIN2A, GRIN2B) encoding genes. In an independent expert-curated dataset of 1,422 neurodevelopmental disorder pathogenic patient variants, and 679 electrophysiological experiments that pore axis distance is associated with seizure age of onset and cognitive performance as well as differential gain vs. loss-of-channel function.In summary, we identified biological properties associated with ion-channel malfunction and show that these are correlated with in vitro functional read-outs and clinical phenotypes in patients with neurodevelopmental disorders. Our results suggest that clinical decision support algorithms that predict variant pathogenicity and function are feasible in the future.Competing Interest StatementThe authors have declared no competing interest.DSSPDictionary of Protein Secondary StructuregnomADGenome aggregation DatabaseGoFGain of functionGRIN genesGRIN1, GRIN2A. GRIN2BHGMDHuman Gene Mutation DatabaseNMDA receptorN-methyl-D-aspartate receptorGABA receptorGamma-aminobutyric acid receptorLoFLoss of functionSCN genesSCN1A, SCN2A, SCN8AVCFVariant Call Format [less ▲]

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See detailSpectrum of Phenotypic, Genetic, and Functional Characteristics in Epilepsy Patients With KCNC2 Pathogenic Variants 10.1212/WNL.0000000000200660
Schwarz, Niklas; Seiffert, Simone; Pendziwiat, Manuela et al

in Neurology (2022)

Background: KCNC2 encodes Kv3.2, a member of the Shaw-related (Kv3) voltage-gated potassium channel subfamily, which is important for sustained high-frequency firing and optimized energy efficiency of ... [more ▼]

Background: KCNC2 encodes Kv3.2, a member of the Shaw-related (Kv3) voltage-gated potassium channel subfamily, which is important for sustained high-frequency firing and optimized energy efficiency of action potentials in the brain. The objective of this study was to analyse the clinical phenotype, genetic background, and biophysical function of disease-associated Kv3.2 variants.Methods: Individuals with KCNC2 variants detected by exome sequencing were selected for clinical, further genetic, and functional analysis. Cases were referred through clinical and research collaborations. Selected de novo variants were examined electrophysiologically in Xenopus laevis oocytes.Results: We identified novel KCNC2 variants in 18 patients with various forms of epilepsy including genetic generalized epilepsy (GGE), developmental and epileptic encephalopathy (DEE) including early-onset absence epilepsy (EOAE), focal epilepsy (FE), and myoclonic-atonic epilepsy (MAE). 10/18 variants were de novo and 8/18 variants were classified as modifying variants. 8 drug responsive cases became seizure-free using valproic acid as monotherapy or in combination including severe DEE cases. Functional analysis of four variants demonstrated gain-of-function in three severely affected DEE cases and loss-of-function in one case with a milder phenotype (GGE) as the underlying pathomechanisms.Conclusion: These findings implicate KCNC2 as a novel causative gene for epilepsy and emphasize the critical role of KV3.2 in the regulation of brain excitability. [less ▲]

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See detailClinically relevant combined effect of polygenic background, rare pathogenic germline variants, and family history on colorectal cancer incidence 2022.01.20.22269585
Hassanin, Emadeldin; Spier, Isabel; Bobbili, Dheeraj Reddy UL et al

E-print/Working paper (2022)

Background and aims: Summarised in polygenic risk scores (PRS), the effect of common, low penetrant genetic variants associated with colorectal cancer (CRC), can be used for risk stratification.Methods To ... [more ▼]

Background and aims: Summarised in polygenic risk scores (PRS), the effect of common, low penetrant genetic variants associated with colorectal cancer (CRC), can be used for risk stratification.Methods To assess the combined impact of the PRS and other main factors on CRC risk, 163,516 individuals from the UK Biobank were stratified as follows: 1. carriers status for germline pathogenic variants (PV) in CRC susceptibility genes (APC, MLH1, MSH2, MSH6, PMS2), 2. low (<20%), intermediate (20-80%), or high PRS (>80\%), and 3. family history (FH) of CRC. Multivariable logistic regression and Cox proportional hazards models were applied to compare odds ratios (OR) and to compute the lifetime incidence, respectively. Results: Depending on the PRS, the CRC lifetime incidence for non-carriers ranges between 6 and 22\%, compared to 40 and 74 for carriers. A suspicious FH is associated with a further increase of the cumulative incidence reaching 26 for non-carriers and 98 for carriers. In non-carriers without FH, but high PRS, the CRC risk is doubled, whereas a low PRS even in the context of a FH results in a decreased risk. The full model including PRS, carrier status, and FH improved the area under the curve (AUC) in risk prediction (0.704). Conclusion: The findings demonstrate that CRC risks are strongly influenced by the PRS for both a sporadic and monogenic background. FH, PV, and common variants complementary contribute to CRC risk. The implementation of PRS in routine care will likely improve personalized risk stratification, which will in turn guide tailored preventive surveillance strategies in high, intermediate, and low risk groups. [less ▲]

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See detailAssociation of ultra-rare coding variants with genetic generalized epilepsy: A case–control whole exome sequencing study
Koko, Mahmoud; Motelow, Joshua E.; Stanley, Kate E. et al

in Epilepsia (2022)

Abstract Objective We aimed to identify genes associated with genetic generalized epilepsy (GGE) by combining large cohorts enriched with individuals with a positive family history. Secondarily, we set ... [more ▼]

Abstract Objective We aimed to identify genes associated with genetic generalized epilepsy (GGE) by combining large cohorts enriched with individuals with a positive family history. Secondarily, we set out to compare the association of genes independently with familial and sporadic GGE. Methods We performed a case–control whole exome sequencing study in unrelated individuals of European descent diagnosed with GGE (previously recruited and sequenced through multiple international collaborations) and ancestry-matched controls. The association of ultra-rare variants (URVs; in 18 834 protein-coding genes) with epilepsy was examined in 1928 individuals with GGE (vs. 8578 controls), then separately in 945 individuals with familial GGE (vs. 8626 controls), and finally in 1005 individuals with sporadic GGE (vs. 8621 controls). We additionally examined the association of URVs with familial and sporadic GGE in two gene sets important for inhibitory signaling (19 genes encoding γ-aminobutyric acid type A [GABAA] receptors, 113 genes representing the GABAergic pathway). Results GABRG2 was associated with GGE (p = 1.8 × 10−5), approaching study-wide significance in familial GGE (p = 3.0 × 10−6), whereas no gene approached a significant association with sporadic GGE. Deleterious URVs in the most intolerant subgenic regions in genes encoding GABAA receptors were associated with familial GGE (odds ratio [OR] = 3.9, 95 confidence interval [CI] = 1.9–7.8, false discovery rate [FDR]-adjusted p = .0024), whereas their association with sporadic GGE had marginally lower odds (OR = 3.1, 95 CI = 1.3–6.7, FDR-adjusted p = .022). URVs in GABAergic pathway genes were associated with familial GGE (OR = 1.8, 95 CI = 1.3–2.5, FDR-adjusted p = .0024) but not with sporadic GGE (OR = 1.3, 95 CI = .9–1.9, FDR-adjusted p = .19). Significance URVs in GABRG2 are likely an important risk factor for familial GGE. The association of gene sets of GABAergic signaling with familial GGE is more prominent than with sporadic GGE. [less ▲]

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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 ▲]

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See detailBody-First Subtype of Parkinson's Disease with Probable REM-Sleep Behavior Disorder Is Associated with Non-Motor Dominant Phenotype
Pavelka, Lukas; Rauschenberger, Armin UL; Landoulsi, Zied UL et al

in Journal of Parkinson's Disease (2022)

Background: The hypothesis of body-first vs. brain-first subtype of PD has been proposed with REM-Sleep behavior disorder (RBD) defining the former. The body-first PD presumes an involvement of the ... [more ▼]

Background: The hypothesis of body-first vs. brain-first subtype of PD has been proposed with REM-Sleep behavior disorder (RBD) defining the former. The body-first PD presumes an involvement of the brainstem in the pathogenic process with higher burden of autonomic dysfunction. Objective: To identify distinctive clinical subtypes of idiopathic Parkinson’s disease (iPD) in line with the formerly proposed concept of body-first vs. brain-first subtypes in PD, we analyzed the presence of probable RBD (pRBD), sex, and the APOE ɛ4 carrier status as potential sub-group stratifiers. Methods: A total of 400 iPD patients were included in the cross-sectional analysis from the baseline dataset with a completed RBD Screening Questionnaire (RBDSQ) for classifying as pRBD by using the cut-off RBDSQ≥6. Multiple regression models were applied to explore (i) the effect of pRBD on clinical outcomes adjusted for disease duration and age, (ii) the effect of sex on pRBD, and (iii) the association of APOE ɛ4 and pRBD. Results: iPD-pRBD was significantly associated with autonomic dysfunction (SCOPA-AUT), level of depressive symptoms (BDI-I), MDS-UPDRS I, hallucinations, and constipation, whereas significantly negatively associated with quality of life (PDQ-39) and sleep (PDSS). No significant association between sex and pRBD or APOE ɛ4 and pRBD in iPD was found nor did we determine a significant effect of APOE ɛ4 on the PD phenotype. Conclusion: We identified an RBD-specific PD endophenotype, characterized by predominant autonomic dysfunction, hallucinations, and depression, corroborating the concept of a distinctive body-first subtype of PD. We did not observe a significant association between APOE ɛ4 and pRBD suggesting both factors having an independent effect on cognitive decline in iPD. [less ▲]

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See detailAge at onset as stratifier in idiopathic Parkinson's disease - effect of ageing and polygenic risk score on clinical phenotypes
Pavelka, Lukas; Rauschenberger, Armin UL; Landoulsi, Zied UL et al

in NPJ Parkinson's Disease (2022), 9(8), 102

Several phenotypic differences observed in Parkinson's disease (PD) patients have been linked to age at onset (AAO). We endeavoured to find out whether these differences are due to the ageing process ... [more ▼]

Several phenotypic differences observed in Parkinson's disease (PD) patients have been linked to age at onset (AAO). We endeavoured to find out whether these differences are due to the ageing process itself by using a combined dataset of idiopathic PD (n = 430) and healthy controls (HC; n = 556) excluding carriers of known PD-linked genetic mutations in both groups. We found several significant effects of AAO on motor and non-motor symptoms in PD, but when comparing the effects of age on these symptoms with HC (using age at assessment, AAA), only positive associations of AAA with burden of motor symptoms and cognitive impairment were significantly different between PD vs HC. Furthermore, we explored a potential effect of polygenic risk score (PRS) on clinical phenotype and identified a significant inverse correlation of AAO and PRS in PD. No significant association between PRS and severity of clinical symptoms was found. We conclude that the observed non-motor phenotypic differences in PD based on AAO are largely driven by the ageing process itself and not by a specific profile of neurodegeneration linked to AAO in the idiopathic PD patients. [less ▲]

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See detailAn archaeal compound as a driver of Parkinson’s disease pathogenesis
Trezzi, Jean-Pierre; Aho, Velma UL; Jäger, Christian UL et al

E-print/Working paper (2022)

Patients with Parkinson’s disease (PD) exhibit differences in their gut microbiomes compared to healthy individuals. Although differences have most commonly been described in the abundances of bacterial ... [more ▼]

Patients with Parkinson’s disease (PD) exhibit differences in their gut microbiomes compared to healthy individuals. Although differences have most commonly been described in the abundances of bacterial taxa, changes to viral and archaeal populations have also been observed. Mechanistic links between gut microbes and PD pathogenesis remain elusive but could involve molecules that promote α-synuclein aggregation. Here, we show that 2-hydroxypyridine (2-HP) represents a key molecule for the pathogenesis of PD. We observe significantly elevated 2-HP levels in faecal samples from patients with PD or its prodrome, idiopathic REM sleep behaviour disorder (iRBD), compared to healthy controls. 2-HP is correlated with the archaeal species Methanobrevibacter smithii and with genes involved in methane metabolism, and it is detectable in isolate cultures of M. smithii. We demonstrate that 2-HP is selectively toxic to transgenic α-synuclein overexpressing yeast and increases α-synuclein aggregation in a yeast model as well as in human induced pluripotent stem cell derived enteric neurons. It also exacerbates PD-related motor symptoms, α-synuclein aggregation, and striatal degeneration when injected intrastriatally in transgenic mice overexpressing human α-synuclein. Our results highlight the effect of an archaeal molecule in relation to the gut-brain axis, which is critical for the diagnosis, prognosis, and treatment of PD. [less ▲]

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See detailbinny: an automated binning algorithm to recover high-quality genomes from complex metagenomic datasets 2021.12.22.473795
Hickl, Oskar UL; Teixeira Queiros, Pedro UL; Wilmes, Paul UL et al

E-print/Working paper (2021)

The reconstruction of genomes is a critical step in genome-resolved metagenomics as well as for multi-omic data integration from microbial communities. Here, we present binny, a binning tool that produces ... [more ▼]

The reconstruction of genomes is a critical step in genome-resolved metagenomics as well as for multi-omic data integration from microbial communities. Here, we present binny, a binning tool that produces high-quality metagenome-assembled genomes from both contiguous and highly fragmented genomes. Based on established metrics, binny outperforms existing state-of-the-art binning methods and finds unique genomes that could not be detected by other methods.binny uses k-mer-composition and coverage by metagenomic reads for iterative, non-linear dimension reduction of genomic signatures as well as subsequent automated contig clustering with cluster assessment using lineage-specific marker gene sets.When compared to five widely used binning algorithms, binny recovers the most near-complete (\>95 pure, \>90 complete) and high-quality (\>90 pure, \>70 complete) genomes from simulated data sets from the Critical Assessment of Metagenome Interpretation (CAMI) initiative, as well as from a real-world benchmark comprised of metagenomes from various environments. binny is implemented as Snakemake workflow and available from https://github.com/a-h-b/binny.Competing Interest StatementThe authors have declared no competing interest. [less ▲]

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See detailBreast and prostate cancer risk: the interplay of polygenic risk, rare pathogenic germline variants, and family history
Hassanin, Emadeldin; May, Patrick UL; Aldisi, Rana et al

in Genetics in Medicine (2021)

Purpose Investigate to which extent polygenic risk scores (PRS), pathogenic or likely rare pathogenic germline variants (PV), and family history jointly influence breast and prostate cancer risk. Methods ... [more ▼]

Purpose Investigate to which extent polygenic risk scores (PRS), pathogenic or likely rare pathogenic germline variants (PV), and family history jointly influence breast and prostate cancer risk. Methods 200,643 individuals from the UK Biobank were stratified as follows: 1. Heterozygotes or non-heterozygotes of PV in moderate to high cancer risk genes, 2. PRS strata, 3. with or without a family history of cancer. Multivariable logistic regression and Cox proportional hazards models were used to compute the odds ratio (OR) across groups and the cumulative incidence through life. Results Cumulative incidence by age 70 among non-heterozygotes across PRS strata ranged from 9% to 32% and from 9% to 35% for breast and prostate cancer, respectively. Among PV heterozygotes it ranged from 20% to 48% in moderate-risk genes and from 51% to 74% in high-risk genes for breast cancer, and it ranged from 30% to 59% in prostate cancer risk genes. Family history is always associated with an increased cancer OR. Conclusion PRS provides a meaningful risk gradient leading alone to a cancer risk comparable to PV in moderate risk genes while acting as risk modifier for high-risk genes. Including family history beside PV and PRS further improves cancer risk stratification. [less ▲]

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See detailGenome Sequencing of SARS-CoV-2 Allows Monitoring of Variants of Concern through Wastewater
Herold, Malte; Fouquier d'herouël, Aymeric UL; May, Patrick UL et al

in Water (2021), 13(21 3018),

Monitoring SARS-CoV-2 in wastewater has shown to be an effective tool for epidemiological surveillance. More specifically, RNA levels determined with RT-qPCR have been shown to track with the infection ... [more ▼]

Monitoring SARS-CoV-2 in wastewater has shown to be an effective tool for epidemiological surveillance. More specifically, RNA levels determined with RT-qPCR have been shown to track with the infection dynamics within the population. However, the surveillance of individual lineages circulating in the population based on genomic sequencing of wastewater samples is challenging, as the genetic material constitutes a mixture of different viral haplotypes. Here, we identify specific signature mutations from individual SARS-CoV-2 lineages in wastewater samples to estimate lineages circulating in Luxembourg. We compare circulating lineages and mutations to those detected in clinical samples amongst infected individuals. We show that especially for dominant lineages, the allele frequencies of signature mutations correspond to the occurrence of particular lineages in the population. In addition, we provide evidence that regional clusters can also be discerned. We focused on the time period between November 2020 and March 2021 in which several variants of concern emerged and specifically traced the lineage B.1.1.7, which became dominant in Luxembourg during that time. During the subsequent time points, we were able to reconstruct short haplotypes, highlighting the co-occurrence of several signature mutations. Our results highlight the potential of genomic surveillance in wastewater samples based on amplicon short-read data. By extension, our work provides the basis for the early detection of novel SARS-CoV-2 variants. [less ▲]

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See detailGenetic evaluation of dementia with Lewy bodies implicates distinct disease subgroups
Kaivola, Karri; Shah, Zalak; Chia, Ruth et al

in Brain: a Journal of Neurology (2021), awab402

The APOE locus is strongly associated with risk for developing Alzheimer’s disease and dementia with Lewy bodies (DLB). In particular, the role of the APOE ε4 allele as a putative driver of α-synuclein ... [more ▼]

The APOE locus is strongly associated with risk for developing Alzheimer’s disease and dementia with Lewy bodies (DLB). In particular, the role of the APOE ε4 allele as a putative driver of α-synuclein pathology is a topic of intense debate. Here, we performed a comprehensive evaluation in 2,466 DLB cases versus 2,928 neurologically healthy, aged controls. Using an APOE-stratified genome-wide association study approach, we found that GBA is associated with risk for DLB in patients without APOE ε4 (p = 6.58 x 10−9, OR = 3.41, 95% CI = 2.25–5.17), but not with DLB with APOE ε4 (p = 0.034, OR = 1.87, 95%, 95% CI = 1.05–3.37). We then divided 495 neuropathologically examined DLB cases into three groups based on the extent of concomitant Alzheimer’s disease co-pathology: pure DLB (n = 88), DLB with intermediate Alzheimer’s disease co-pathology (DLB + iAD, n = 66), and DLB with high Alzheimer’s disease co-pathology (DLB + AD, n = 341). In each group, we tested the association of the APOE ε4 against the 2,928 neurologically healthy controls. Our examination found that APOE ε4 was associated with DLB + AD (p = 1.29x10−32, OR = 4.25, 95% CI = 3.35–5.39) and DLB + iAD (p = 0.0011, OR = 2.31, 95% CI = 1.40–3.83), but not with pure DLB (p = 0.31, OR = 0.75, 95% CI = 0.43–1.30). In conclusion, though deep clinical data were not available for these samples, our findings do not support the notion that APOE ε4 is an independent driver of α-synuclein pathology in pure DLB, but rather implicate GBA as the main risk gene for the pure DLB subgroup. [less ▲]

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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 ▲]

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See detailDistinct gene-set burden patterns underlie common generalized and focal epilepsies
Koko, Mahmoud; Krause, Roland UL; Sander, Thomas et al

in EBioMedicine (2021), 72

Background Analyses of few gene-sets in epilepsy showed a potential to unravel key disease associations. We set out to investigate the burden of ultra-rare variants (URVs) in a comprehensive range of ... [more ▼]

Background Analyses of few gene-sets in epilepsy showed a potential to unravel key disease associations. We set out to investigate the burden of ultra-rare variants (URVs) in a comprehensive range of biologically informed gene-sets presumed to be implicated in epileptogenesis. Methods The burden of 12 URV types in 92 gene-sets was compared between cases and controls using whole exome sequencing data from individuals of European descent with developmental and epileptic encephalopathies (DEE, n = 1,003), genetic generalized epilepsy (GGE, n = 3,064), or non-acquired focal epilepsy (NAFE, n = 3,522), collected by the Epi25 Collaborative, compared to 3,962 ancestry-matched controls. Findings Missense URVs in highly constrained regions were enriched in neuron-specific and developmental genes, whereas genes not expressed in brain were not affected. GGE featured a higher burden in gene-sets derived from inhibitory vs. excitatory neurons or associated receptors, whereas the opposite was found for NAFE, and DEE featured a burden in both. Top-ranked susceptibility genes from recent genome-wide association studies (GWAS) and gene-sets derived from generalized vs. focal epilepsies revealed specific enrichment patterns of URVs in GGE vs. NAFE. Interpretation Missense URVs affecting highly constrained sites differentially impact genes expressed in inhibitory vs. excitatory pathways in generalized vs. focal epilepsies. The excess of URVs in top-ranked GWAS risk-genes suggests a convergence of rare deleterious and common risk-variants in the pathogenesis of generalized and focal epilepsies. [less ▲]

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