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1.
J Mol Diagn ; 22(9): 1205-1215, 2020 09.
Article in English | MEDLINE | ID: mdl-32619640

ABSTRACT

Autozygosity is associated with an increased risk of genetic rare disease, thus being a relevant factor for clinical genetic studies. More than 2400 exome sequencing data sets were analyzed and screened for autozygosity on the basis of detection of >1 Mbp runs of homozygosity (ROHs). A model was built to predict if an individual is likely to be a consanguineous offspring (accuracy, 98%), and probability of consanguinity ranges were established according to the total ROH size. Application of the model resulted in the reclassification of the consanguinity status of 12% of the patients. The analysis of a subset of 79 consanguineous cases with the Rare Disease (RD)-Connect Genome-Phenome Analysis Platform, combining variant filtering and homozygosity mapping, enabled a 50% reduction in the number of candidate variants and the identification of homozygous pathogenic variants in 41 patients, with an overall diagnostic yield of 52%. The newly defined consanguinity ranges provide, for the first time, specific ROH thresholds to estimate inbreeding within a pedigree on disparate exome sequencing data, enabling confirmation or (re)classification of consanguineous status, hence increasing the efficiency of molecular diagnosis and reporting on secondary consanguinity findings, as recommended by American College of Medical Genetics and Genomics guidelines.


Subject(s)
Exome Sequencing/methods , Homozygote , Molecular Diagnostic Techniques/methods , Rare Diseases/diagnosis , Rare Diseases/genetics , Consanguinity , Exome , Genome, Human , Humans , Models, Genetic , Pedigree , Polymorphism, Single Nucleotide , Rare Diseases/epidemiology , Rare Diseases/ethnology
5.
Endocrinology ; 160(7): 1731-1742, 2019 07 01.
Article in English | MEDLINE | ID: mdl-31125048

ABSTRACT

Most patients with pancreatic cancer present with advanced disease and die within the first year after diagnosis. Predictive biomarkers that signal the presence of pancreatic cancer in an early stage are desperately needed. We aimed to identify new and validate previously found plasma metabolomic biomarkers associated with early stages of pancreatic cancer. Prediagnostic blood samples from individuals who were to receive a diagnosis of pancreatic cancer between 1 month and 17 years after sampling (N = 356) and age- and sex-matched controls (N = 887) were collected from five large population cohorts (HUNT2, HUNT3, FINRISK, Estonian Biobank, Rotterdam Study). We applied proton nuclear magnetic resonance-based metabolomics on the Nightingale platform. Logistic regression identified two interesting hits: glutamine (P = 0.011) and histidine (P = 0.012), with Westfall-Young family-wise error rate adjusted P values of 0.43 for both. Stratification in quintiles showed a 1.5-fold elevated risk for the lowest 20% of glutamine and a 2.2-fold increased risk for the lowest 20% of histidine. Stratification by time to diagnosis suggested glutamine to be involved in an earlier process (2 to 5 years before diagnosis), and histidine in a process closer to the actual onset (<2 years). Our data did not support the branched-chain amino acids identified earlier in several US cohorts as potential biomarkers for pancreatic cancer. Thus, although we identified glutamine and histidine as potential biomarkers of biological interest, our results imply that a study at this scale does not yield metabolomic biomarkers with sufficient predictive value to be clinically useful per se as prognostic biomarkers.


Subject(s)
Biomarkers, Tumor/blood , Glutamine/blood , Histidine/blood , Pancreatic Neoplasms/diagnosis , Aged , Biological Specimen Banks , Case-Control Studies , Early Diagnosis , Europe , Female , Humans , Magnetic Resonance Spectroscopy , Male , Metabolomics , Middle Aged , Pancreatic Neoplasms/blood
6.
N Biotechnol ; 49: 98-103, 2019 Mar 25.
Article in English | MEDLINE | ID: mdl-30342241

ABSTRACT

Biobank samples and data from studies of large prospective cohorts (LPC) represent an invaluable resource for health research. Efficient sharing and pooling of samples and data is a central pre-requisite for new advances in biomedical science. This requirement, however, is not compatible with the present scattered and traditional access governance structures, where legal and ethical frameworks often form an obstacle for effective sharing. Moreover, the EU General Data Protection Regulation (GDPR) is demanding increasingly rigorous administration from all those organisations processing personal data. The BBMRI-LPC project (Biobanking and Biomolecular Research Infrastructure - Large Prospective Cohorts) assembled 21 LPCs from 10 countries and two EU-wide multinational cohort networks with a key objective to promote collaborative innovative transnational research proposed by external researchers on the broad field of common chronic diseases, and analyze the gaps and needs involved. BBMRI-LPC organized three scientific calls to offer European investigators an opportunity to gain free of charge transnational access to research material available in the participating cohorts. A total of 11 high-quality research proposals involving multiple prospective cohorts were granted, and the access process in the individual projects carefully monitored. Divergent access governance structures, complex legal and ethical frameworks and heterogeneous procedures were identified as currently constituting substantial obstacles for sample and data transfer in Europe. To optimize the scientific value and use of these research resources, practical solutions for more streamlined access governance in collaborative projects are urgently needed. A number of infrastructure developments could be made to improve time-efficiency in access provision.


Subject(s)
International Cooperation , Prospective Studies , Access to Information , Biological Specimen Banks , Biomedical Research , Europe , Humans
7.
Biopreserv Biobank ; 17(1): 46-51, 2019.
Article in English | MEDLINE | ID: mdl-30499696

ABSTRACT

Public-private partnerships (PPP) are an efficient means to advance scientific discoveries and boost the medical innovations needed to improve precision medicine. The increasing number and novel nature of such collaborations is keeping the biomedical field in constant flux. Here we provide an update on PPP development involving academic biobanks in the BBMRI community (the European Biobanking and BioMolecular Resources Research Infrastructure) and report the views on PPP of 20 key players from this field. The interviewed academic representants broadly show interest for their institution to establish PPP and initiate or partner with BBMRI expert centers. The results indicate that PPP has gained foothold in this area of biomedical research, with great promise to facilitate access to samples and data and to improve data interoperability and reproducibility.


Subject(s)
Biological Specimen Banks/organization & administration , Biomedical Research/organization & administration , Public-Private Sector Partnerships/organization & administration , Databases, Factual , Europe , Health Resources , Humans , Information Dissemination/methods , Organizations , Precision Medicine/methods , Reproducibility of Results
8.
Biopreserv Biobank ; 16(2): 97-105, 2018 Apr.
Article in English | MEDLINE | ID: mdl-29359962

ABSTRACT

The known challenge of underutilization of data and biological material from biorepositories as potential resources for medical research has been the focus of discussion for over a decade. Recently developed guidelines for improved data availability and reusability-entitled FAIR Principles (Findability, Accessibility, Interoperability, and Reusability)-are likely to address only parts of the problem. In this article, we argue that biological material and data should be viewed as a unified resource. This approach would facilitate access to complete provenance information, which is a prerequisite for reproducibility and meaningful integration of the data. A unified view also allows for optimization of long-term storage strategies, as demonstrated in the case of biobanks. We propose an extension of the FAIR Principles to include the following additional components: (1) quality aspects related to research reproducibility and meaningful reuse of the data, (2) incentives to stimulate effective enrichment of data sets and biological material collections and its reuse on all levels, and (3) privacy-respecting approaches for working with the human material and data. These FAIR-Health principles should then be applied to both the biological material and data. We also propose the development of common guidelines for cloud architectures, due to the unprecedented growth of volume and breadth of medical data generation, as well as the associated need to process the data efficiently.


Subject(s)
Biological Specimen Banks , Confidentiality/standards , Databases, Factual/standards , Information Dissemination/methods , Biological Specimen Banks/organization & administration , Biological Specimen Banks/standards , Guidelines as Topic , Humans
10.
PLoS One ; 12(6): e0178556, 2017.
Article in English | MEDLINE | ID: mdl-28570578

ABSTRACT

Huntington disease is associated with elongation of a CAG repeat in the HTT gene that results in a mutant huntingtin protein. Several studies have implicated N-terminal huntingtin protein fragments in Huntington disease pathogenesis. Ideally, these fragments are studied in human brain tissue. However, the use of human brain tissue comes with certain unavoidable variables such as post mortem delay, artefacts from freeze-thaw cycles and subject-to-subject variation. Knowledge on how these variables might affect N-terminal huntingtin protein fragments in post mortem human brain is important for a proper interpretation of study results. The effect of post mortem delay on protein in human brain is known to vary depending on the protein of interest. In the present study, we have assessed the effect of post mortem delay on N-terminal huntingtin protein fragments using western blot. We mimicked post mortem delay in one individual control case and one individual Huntington disease case with low initial post mortem delay. The influence of subject-to-subject variation on N-terminal huntingtin fragments was assessed in human cortex and human striatum using two cohorts of control and Huntington disease subjects. Our results show that effects of post mortem delay on N-terminal huntingtin protein fragments are minor in our individual subjects. Additionally, one freeze-thaw cycle decreases the huntingtin western blot signal intensity in the cortex control subject, but does not introduce additional N-terminal huntingtin fragments. Our results suggest that subject-to-subject variation contributes more to variability in N-terminal huntingtin fragments than post mortem delay.


Subject(s)
Brain/metabolism , Huntingtin Protein/metabolism , Huntington Disease/pathology , 3' Untranslated Regions , Aged , Aged, 80 and over , Amino Acid Sequence , Brain/pathology , Case-Control Studies , Cell Line , Female , HEK293 Cells , Humans , Huntington Disease/metabolism , Male , Middle Aged , Open Reading Frames , Postmortem Changes , Sequence Homology, Amino Acid
11.
Eur J Hum Genet ; 2017 May 10.
Article in English | MEDLINE | ID: mdl-28488676
12.
Sci Rep ; 7: 44849, 2017 03 21.
Article in English | MEDLINE | ID: mdl-28322270

ABSTRACT

There is widespread transcriptional dysregulation in Huntington's disease (HD) brain, but analysis is inevitably limited by advanced disease and postmortem changes. However, mutant HTT is ubiquitously expressed and acts systemically, meaning blood, which is readily available and contains cells that are dysfunctional in HD, could act as a surrogate for brain tissue. We conducted an RNA-Seq transcriptomic analysis using whole blood from two HD cohorts, and performed gene set enrichment analysis using public databases and weighted correlation network analysis modules from HD and control brain datasets. We identified dysregulated gene sets in blood that replicated in the independent cohorts, correlated with disease severity, corresponded to the most significantly dysregulated modules in the HD caudate, the most prominently affected brain region, and significantly overlapped with the transcriptional signature of HD myeloid cells. High-throughput sequencing technologies and use of gene sets likely surmounted the limitations of previously inconsistent HD blood expression studies. Our results suggest transcription is disrupted in peripheral cells in HD through mechanisms that parallel those in brain. Immune upregulation in HD overlapped with Alzheimer's disease, suggesting a common pathogenic mechanism involving macrophage phagocytosis and microglial synaptic pruning, and raises the potential for shared therapeutic approaches.


Subject(s)
Alzheimer Disease/etiology , Brain/metabolism , Gene Expression Regulation , Huntington Disease/etiology , Immunity/genetics , Transcriptome , Adult , Aged , Alzheimer Disease/blood , Alzheimer Disease/diagnosis , Alzheimer Disease/metabolism , Biomarkers , Case-Control Studies , Female , Gene Expression Profiling , Gene Regulatory Networks , High-Throughput Nucleotide Sequencing , Humans , Huntington Disease/blood , Huntington Disease/diagnosis , Huntington Disease/metabolism , Male , Middle Aged , Myeloid Cells/immunology , Myeloid Cells/metabolism , Prefrontal Cortex/metabolism , Signal Transduction , Young Adult
15.
Nat Commun ; 7: 12989, 2016 10 06.
Article in English | MEDLINE | ID: mdl-27708267

ABSTRACT

Structural variation (SV) represents a major source of differences between individual human genomes and has been linked to disease phenotypes. However, the majority of studies provide neither a global view of the full spectrum of these variants nor integrate them into reference panels of genetic variation. Here, we analyse whole genome sequencing data of 769 individuals from 250 Dutch families, and provide a haplotype-resolved map of 1.9 million genome variants across 9 different variant classes, including novel forms of complex indels, and retrotransposition-mediated insertions of mobile elements and processed RNAs. A large proportion are previously under reported variants sized between 21 and 100 bp. We detect 4 megabases of novel sequence, encoding 11 new transcripts. Finally, we show 191 known, trait-associated SNPs to be in strong linkage disequilibrium with SVs and demonstrate that our panel facilitates accurate imputation of SVs in unrelated individuals.


Subject(s)
Genome, Human , Genomic Structural Variation , Genomics , Algorithms , Chromosomes/ultrastructure , Computational Biology , Gene Deletion , Genotype , Haplotypes , Humans , INDEL Mutation , Linkage Disequilibrium , Netherlands , Polymerase Chain Reaction , Polymorphism, Single Nucleotide , RNA/metabolism , Sequence Analysis, DNA , Sequence Analysis, RNA , Software
16.
Metabolomics ; 12: 137, 2016.
Article in English | MEDLINE | ID: mdl-27524956

ABSTRACT

INTRODUCTION: Metabolic changes have been frequently associated with Huntington's disease (HD). At the same time peripheral blood represents a minimally invasive sampling avenue with little distress to Huntington's disease patients especially when brain or other tissue samples are difficult to collect. OBJECTIVES: We investigated the levels of 163 metabolites in HD patient and control serum samples in order to identify disease related changes. Additionally, we integrated the metabolomics data with our previously published next generation sequencing-based gene expression data from the same patients in order to interconnect the metabolomics changes with transcriptional alterations. METHODS: This analysis was performed using targeted metabolomics and flow injection electrospray ionization tandem mass spectrometry in 133 serum samples from 97 Huntington's disease patients (29 pre-symptomatic and 68 symptomatic) and 36 controls. RESULTS: By comparing HD mutation carriers with controls we identified 3 metabolites significantly changed in HD (serine and threonine and one phosphatidylcholine-PC ae C36:0) and an additional 8 phosphatidylcholines (PC aa C38:6, PC aa C36:0, PC ae C38:0, PC aa C38:0, PC ae C38:6, PC ae C42:0, PC aa C36:5 and PC ae C36:0) that exhibited a significant association with disease severity. Using workflow based exploitation of pathway databases and by integrating our metabolomics data with our gene expression data from the same patients we identified 4 deregulated phosphatidylcholine metabolism related genes (ALDH1B1, MBOAT1, MTRR and PLB1) that showed significant association with the changes in metabolite concentrations. CONCLUSION: Our results support the notion that phosphatidylcholine metabolism is deregulated in HD blood and that these metabolite alterations are associated with specific gene expression changes.

17.
Brain ; 139(Pt 4): 1123-35, 2016 Apr.
Article in English | MEDLINE | ID: mdl-26912635

ABSTRACT

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy, or CADASIL, is a hereditary cerebral small vessel disease caused by characteristic cysteine altering missense mutations in the NOTCH3 gene. NOTCH3 mutations in CADASIL result in an uneven number of cysteine residues in one of the 34 epidermal growth factor like-repeat (EGFr) domains of the NOTCH3 protein. The consequence of an unpaired cysteine residue in an EGFr domain is an increased multimerization tendency of mutant NOTCH3, leading to toxic accumulation of the protein in the (cerebro)vasculature, and ultimately reduced cerebral blood flow, recurrent stroke and vascular dementia. There is no therapy to delay or alleviate symptoms in CADASIL. We hypothesized that exclusion of the mutant EGFr domain from NOTCH3 would abolish the detrimental effect of the unpaired cysteine and thus prevent toxic NOTCH3 accumulation and the negative cascade of events leading to CADASIL. To accomplish this NOTCH3 cysteine correction by EGFr domain exclusion, we used pre-mRNA antisense-mediated skipping of specific NOTCH3 exons. Selection of these exons was achieved using in silico studies and based on the criterion that skipping of a particular exon or exon pair would modulate the protein in such a way that the mutant EGFr domain is eliminated, without otherwise corrupting NOTCH3 structure and function. Remarkably, we found that this strategy closely mimics evolutionary events, where the elimination and fusion of NOTCH EGFr domains led to the generation of four functional NOTCH homologues. We modelled a selection of exon skip strategies using cDNA constructs and show that the skip proteins retain normal protein processing, can bind ligand and be activated by ligand. We then determined the technical feasibility of targeted NOTCH3 exon skipping, by designing antisense oligonucleotides targeting exons 2-3, 4-5 and 6, which together harbour the majority of distinct CADASIL-causing mutations. Transfection of these antisense oligonucleotides into CADASIL patient-derived cerebral vascular smooth muscle cells resulted in successful exon skipping, without abrogating NOTCH3 signalling. Combined, these data provide proof of concept for this novel application of exon skipping, and are a first step towards the development of a rational therapeutic approach applicable to up to 94% of CADASIL-causing mutations.


Subject(s)
CADASIL/genetics , Cysteine/genetics , Exons/genetics , Receptors, Notch/genetics , Amino Acid Sequence , CADASIL/diagnosis , Cysteine/chemistry , Genetic Therapy/trends , HEK293 Cells , Humans , Molecular Sequence Data , Muscle, Smooth, Vascular/physiology , Organ Culture Techniques , Protein Structure, Secondary , Receptor, Notch3 , Receptors, Notch/chemistry
18.
PLoS One ; 11(2): e0149621, 2016.
Article in English | MEDLINE | ID: mdl-26919047

ABSTRACT

High-throughput experimental methods such as medical sequencing and genome-wide association studies (GWAS) identify increasingly large numbers of potential relations between genetic variants and diseases. Both biological complexity (millions of potential gene-disease associations) and the accelerating rate of data production necessitate computational approaches to prioritize and rationalize potential gene-disease relations. Here, we use concept profile technology to expose from the biomedical literature both explicitly stated gene-disease relations (the explicitome) and a much larger set of implied gene-disease associations (the implicitome). Implicit relations are largely unknown to, or are even unintended by the original authors, but they vastly extend the reach of existing biomedical knowledge for identification and interpretation of gene-disease associations. The implicitome can be used in conjunction with experimental data resources to rationalize both known and novel associations. We demonstrate the usefulness of the implicitome by rationalizing known and novel gene-disease associations, including those from GWAS. To facilitate the re-use of implicit gene-disease associations, we publish our data in compliance with FAIR Data Publishing recommendations [https://www.force11.org/group/fairgroup] using nanopublications. An online tool (http://knowledge.bio) is available to explore established and potential gene-disease associations in the context of other biomedical relations.


Subject(s)
Computational Biology/methods , Databases, Genetic , Genetic Predisposition to Disease , Genome-Wide Association Study , Humans
19.
Genome Res ; 26(4): 417-26, 2016 Apr.
Article in English | MEDLINE | ID: mdl-26916109

ABSTRACT

Although previous studies have documented a bottleneck in the transmission of mtDNA genomes from mothers to offspring, several aspects remain unclear, including the size and nature of the bottleneck. Here, we analyze the dynamics of mtDNA heteroplasmy transmission in the Genomes of the Netherlands (GoNL) data, which consists of complete mtDNA genome sequences from 228 trios, eight dizygotic (DZ) twin quartets, and 10 monozygotic (MZ) twin quartets. Using a minor allele frequency (MAF) threshold of 2%, we identified 189 heteroplasmies in the trio mothers, of which 59% were transmitted to offspring, and 159 heteroplasmies in the trio offspring, of which 70% were inherited from the mothers. MZ twin pairs exhibited greater similarity in MAF at heteroplasmic sites than DZ twin pairs, suggesting that the heteroplasmy MAF in the oocyte is the major determinant of the heteroplasmy MAF in the offspring. We used a likelihood method to estimate the effective number of mtDNA genomes transmitted to offspring under different bottleneck models; a variable bottleneck size model provided the best fit to the data, with an estimated mean of nine individual mtDNA genomes transmitted. We also found evidence for negative selection during transmission against novel heteroplasmies (in which the minor allele has never been observed in polymorphism data). These novel heteroplasmies are enhanced for tRNA and rRNA genes, and mutations associated with mtDNA diseases frequently occur in these genes. Our results thus suggest that the female germ line is able to recognize and select against deleterious heteroplasmies.


Subject(s)
DNA, Mitochondrial , Family , Genetic Heterogeneity , Inheritance Patterns , White People/genetics , Alleles , Female , Gene Frequency , Humans , Male , Models, Genetic , Models, Statistical , Mutation , Netherlands , Polymorphism, Genetic , Selection, Genetic , Twins
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