Mendelian randomization integrating GWAS and eQTL data reveals genetic determinants of complex and clinical traits

Genome-wide association studies (GWAS) have identified thousands of variants associated with complex traits, but their biological interpretation often remains unclear. Most of these variants overlap with expression QTLs, indicating their potential involvement in regulation of gene expression. Here, we propose a transcriptome-wide summary statistics-based Mendelian Randomization approach (TWMR) that uses multiple SNPs as instruments and multiple gene expression traits as exposures, simultaneously. Applied to 43 human phenotypes, it uncovers 3,913 putatively causal gene-trait associations, 36% of which have no genome-wide significant SNP nearby in previous GWAS. Using independent association summary statistics, we find that the majority of these loci were missed by GWAS due to power issues. Noteworthy among these links is educational attainment-associated BSCL2, known to carry mutations leading to a Mendelian form of encephalopathy. We also find pleiotropic causal effects suggestive of mechanistic connections. TWMR better accounts for pleiotropy and has the potential to identify biological mechanisms underlying complex traits

Refining Attention-Deficit/Hyperactivity Disorder and Autism Spectrum Disorder Genetic Loci by Integrating Summary Data From Genome-wide Association, Gene Expression, and DNA Methylation Studies

Background: Recent genome-wide association studies (GWASs) identified the first genetic loci associated with attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD). The next step is to use these results to increase our understanding of the biological mechanisms involved. Most of the identified variants likely influence gene regulation. The aim of the current study is to shed light on the mechanisms underlying the genetic signals and prioritize genes by integrating GWAS results with gene expression and DNA methylation (DNAm) levels. Methods: We applied summary-data–based Mendelian randomization to integrate ADHD and ASD GWAS data with fetal brain expression and methylation quantitative trait loci, given the early onset of these disorders. We also analyzed expression and methylation quantitative trait loci datasets of adult brain and blood, as these provide increased statistical power. We subsequently used summary-data–based Mendelian randomization to investigate if the same variant influences both DNAm and gene expression levels. Results: We identified multiple gene expression and DNAm levels in fetal brain at chromosomes 1 and 17 that were associated with ADHD and ASD, respectively, through pleiotropy at shared genetic variants. The analyses in brain and blood showed additional associated gene expression and DNAm levels at the same and additional loci, likely because of increased statistical power. Several of the associated genes have not been identified in ADHD and ASD GWASs before. Conclusions: Our findings identified the genetic variants associated with ADHD and ASD that likely act through gene regulation. This facilitates prioritization of candidate genes for functional follow-up studies

New irreversible α-ʟ-iduronidase inhibitors and activity-based probes

Cyclophellitol aziridines are potent irreversible inhibitors of retaining glycosidases and versatile intermediates in the synthesis of activity‐based glycosidase probes (ABPs). Direct 3‐amino‐2‐(trifluoromethyl)quinazolin‐4(3H)‐one‐mediated aziridination of ʟ‐ido‐configured cyclohexene has enabled the synthesis of new covalent inhibitors and ABPs of α‐ʟ‐iduronidase, deficiency of which underlies the lysosomal storage disorder mucopolysaccharidosis type I (MPS I). The iduronidase ABPs react covalently and irreversibly in an activity‐based manner with human recombinant α‐ʟ‐iduronidase (rIDUA, Aldurazyme®). The structures of IDUA when complexed with the inhibitors in a non‐covalent transition state mimicking form and a covalent enzyme‐bound form provide insights into its conformational itinerary. Inhibitors 1–3 adopt a half‐chair conformation in solution (4H3 and 3H4), as predicted by DFT calculations, which is different from the conformation of the Michaelis complex observed by crystallographic studies. Consequently, 1–3 may need to overcome an energy barrier in order to switch from the 4H3 conformation to the transition state (2, 5B) binding conformation before reacting and adopting a covalent 5S1 conformation. rIDUA can be labeled with fluorescent Cy5 ABP 2, which allows monitoring of the delivery of therapeutic recombinant enzyme to lysosomes, as is intended in enzyme replacement therapy for the treatment of MPS I patients

Genome-wide study of DNA methylation shows alterations in metabolic, inflammatory, and cholesterol pathways in ALS

Copyright © 2022 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease with an estimated heritability between 40 and 50%. DNA methylation patterns can serve as proxies of (past) exposures and disease progression, as well as providing a potential mechanism that mediates genetic or environmental risk. Here, we present a blood-based epigenome-wide association study meta-analysis in 9706 samples passing stringent quality control (6763 patients, 2943 controls). We identified a total of 45 differentially methylated positions (DMPs) annotated to 42 genes, which are enriched for pathways and traits related to metabolism, cholesterol biosynthesis, and immunity. We then tested 39 DNA methylation-based proxies of putative ALS risk factors and found that high-density lipoprotein cholesterol, body mass index, white blood cell proportions, and alcohol intake were independently associated with ALS. Integration of these results with our latest genome-wide association study showed that cholesterol biosynthesis was potentially causally related to ALS. Last, DNA methylation at several DMPs and blood cell proportion estimates derived from DNA methylation data were associated with survival rate in patients, suggesting that they might represent indicators of underlying disease processes potentially amenable to therapeutic interventions.The research reported in this publication was supported by grants from The Dutch Research Council (NWO) (VENI scheme grant 09150161810018 to W.v.R.) and Prinses Beatrix Spierfond (neuromuscular fellowship grant W.F19-03 to W.v.R.), The Prinses Beatrix Spierfonds (W.OR20-08 to J.J.F.A.v.V. and J.H.V.), The Canadian Institutes of Health Research (FRN 159279 to J.P.R.), The Dutch Research Council (NWO) (VIDI grant 91719350 to K.P.K.), The European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant agreement no. 772376-EScORIAL to J.H.V.), the Swedish Brain Foundation (grant nos. 2012-0262, 2012-0305, 2013-0279, 2016-0303, 2018-0310, and 2020-0353 to P.M.A.), the Swedish Research Council (grant nos. 2012-3167 and 2017-03100 to P.M.A.), the Knut and Alice Wallenberg Foundation (grant nos. 2012.0091, 2014.0305, and 2020.0232 to P.M.A.), the Ulla-Carin Lindquist Foundation and the Västerbotten County Council (grant no. 56103-7002829 to P.M.A.), and King Gustaf V’s and Queen Victoria’s Freemason’s Foundation. This is an EU Joint Programme–Neurodegenerative Disease Research (JPND) project. The project is supported through the following funding organizations under the aegis of JPND (www.jpnd.eu) [United Kingdom, Medical Research Council (MR/L501529/1; MR/R024804/1) and Economic and Social Research Council (ES/L008238/1)] and through the Motor Neurone Disease Association (MNDA). This study represents independent research part funded by the National Institute for Health Research (NIHR) Biomedical Research Centre at South London and Maudsley NHS Foundation Trust and King’s College London. A.A.-C. is supported by an NIHR Senior Investigator Award. Samples used in this research were entirely/in part obtained from the U.K. National DNA Bank for MND Research, funded by the MND Association and the Wellcome Trust. We would like to thank people with MND and their families for their participation in this project. We acknowledge sample management undertaken by Biobanking Solutions funded by the Medical Research Council at the Centre for Integrated Genomic Medical Research, University of Manchester. R.J.P. is funded through the Gravitation program of the Dutch Ministry of Education, Culture, and Science and the Netherlands Organization for Scientific Research (BRAINSCAPES). G.L.S. was supported by a PhD studentship from the Alzheimer’s Society. S.T.N. acknowledges support through a FightMND Mid-Career Fellowship. V.S. is supported by the Italian Ministry of Health, AriSLA, and E-Rare Joint Transnational Call. A.A.K. is funded by the MNDA and NIHR Maudsley Biomedical Research Centre. D.B., E.T., and H.R. are employees of Biogen. L.H.v.d.B. reports grants from the Netherlands ALS Foundation, grants from The Netherlands Organization for Health Research and Development (Vici scheme), grants from The European Community’s Health Seventh Framework Programme [grant agreement no. 259867 (EuroMOTOR) to L.H.v.d.B.], and grants from The Netherlands Organization for Health Research and Development (the STRENGTH project, funded through the EU Joint Programme–Neurodegenerative Disease Research, JPND), during the conduct of the study. Project MinE Belgium was supported by a grant from IWT (no. 140935), the ALS Liga België, the National Lottery of Belgium, and the KU Leuven Opening the Future Fund. P.V.D. holds a senior clinical investigatorship of FWO-Vlaanderen and is supported by the E. von Behring Chair for Neuromuscular and Neurodegenerative Disorders, the ALS Liga België, and the KU Leuven funds “Een Hart voor ALS”, “Laeversfonds voor ALS Onderzoek”, and the “Valéry Perrier Race against ALS Fund”. This work was supported by the Italian Ministry of Health (Ministero della Salute, Ricerca Sanitaria Finalizzata, grant RF-2016-02362405 to A. Chiò), the Progetti di Rilevante Interesse Nazionale program of the Ministry of Education, University and Research (grant 2017SNW5MB to A. Chiò); the European Commission’s Health Seventh Framework Programme (FP7/2007-2013 under grant agreement 259867 to A. Chiò), and the Joint Programme–Neurodegenerative Disease Research (Strength, ALS-Care and Brain-Mend projects), granted by Italian Ministry of Education, University, and Research. This study was performed under the Department of Excellence grant of the Italian Ministry of Education, University and Research to the “Rita Levi Montalcini” Department of Neuroscience, University of Torino, Italy. We acknowledge funding from the Australian National Health and Medical Research (NHMRC) Council: 1151854, 1083187, 1173790, 1078901, 1113400, 1095215, and 1176913 Enabling Grant #402703 to N.R.W. Additional funding was provided by the Motor Neurone Disease Research Institute of Australia Ice Bucket Challenge grant for the SALSA-SGC consortium. The OATS (used for controls) was facilitated through Twins Research Australia, a national resource in part supported by a Centre for Research Excellence from the Australian NHMRC Council (NHMRC 1079102 to N.R.W.). Funding for this study was awarded by the (NHMRC)/Australian Research Council Strategic Award (grant 401162 to N.R.W.) and NHMRC grants (1405325, 1024224, 1025243, 1045325, 1085606, 568969, and 1093083 to N.R.W.). The collaboration project is cofunded by the PPP Allowance made available by Health~Holland, Top Sector Life Sciences & Health, to stimulate public-private partnerships. This study was supported by the ALS Foundation Netherlands. This work was sponsored by NWO Domain Science for the use of the national computer facilities. A.N.B. is grateful to the Suna and Inan Kirac Foundation and Koc University for the excellent research environment created and for financial support. G.A.R. is supported by the Canadian Institutes of Health. Several authors of this publication are members of the Netherlands Neuromuscular Center (NL-NMD) and the European Reference Network for rare neuromuscular diseases EURO-NMD. French ALS patients of the Pitié-Salpêtrière hospital (Paris) have been collected with ARSla funding support.info:eu-repo/semantics/publishedVersio

Refining Attention-Deficit/Hyperactivity Disorder and Autism Spectrum Disorder Genetic Loci by Integrating Summary Data From Genome-wide Association, Gene Expression, and DNA Methylation Studies

Background: Recent genome-wide association studies (GWASs) identified the first genetic loci associated with attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD). The next step is to use these results to increase our understanding of the biological mechanisms involved. Most of the identified variants likely influence gene regulation. The aim of the current study is to shed light on the mechanisms underlying the genetic signals and prioritize genes by integrating GWAS results with gene expression and DNA methylation (DNAm) levels. Methods: We applied summary-data–based Mendelian randomization to integrate ADHD and ASD GWAS data with fetal brain expression and methylation quantitative trait loci, given the early onset of these disorders. We also analyzed expression and methylation quantitative trait loci datasets of adult brain and blood, as these provide increased statistical power. We subsequently used summary-data–based Mendelian randomization to investigate if the same variant influences both DNAm and gene expression levels. Results: We identified multiple gene expression and DNAm levels in fetal brain at chromosomes 1 and 17 that were associated with ADHD and ASD, respectively, through pleiotropy at shared genetic variants. The analyses in brain and blood showed additional associated gene expression and DNAm levels at the same and additional loci, likely because of increased statistical power. Several of the associated genes have not been identified in ADHD and ASD GWASs before. Conclusions: Our findings identified the genetic variants associated with ADHD and ASD that likely act through gene regulation. This facilitates prioritization of candidate genes for functional follow-up studies

Identification of 371 genetic variants for age at first sex and birth linked to externalising behaviour

Age at first sexual intercourse and age at first birth have implications for health and evolutionary fitness. In this genome-wide association study (age at first sexual intercourse, N = 387,338; age at first birth, N = 542,901), we identify 371 single-nucleotide polymorphisms, 11 sex-specific, with a 5–6% polygenic score prediction. Heritability of age at first birth shifted from 9% [CI = 4–14%] for women born in 1940 to 22% [CI = 19–25%] for those born in 1965. Signals are driven by the genetics of reproductive biology and externalising behaviour, with key genes related to follicle stimulating hormone (FSHB), implantation (ESR1), infertility and spermatid differentiation. Our findings suggest that polycystic ovarian syndrome may lead to later age at first birth, linking with infertility. Late age at first birth is associated with parental longevity and reduced incidence of type 2 diabetes and cardiovascular disease. Higher childhood socioeconomic circumstances and those in the highest polygenic score decile (90%+) experience markedly later reproductive onset. Results are relevant for improving teenage and late-life health, understanding longevity and guiding experimentation into mechanisms of infertility

Mendelian randomization integrating GWAS and eQTL data reveals genetic determinants of complex and clinical traits

Abstract Genome-wide association studies (GWAS) have identified thousands of variants associated with complex traits, but their biological interpretation often remains unclear. Most of these variants overlap with expression QTLs, indicating their potential involvement in regulation of gene expression. Here, we propose a transcriptome-wide summary statistics-based Mendelian Randomization approach (TWMR) that uses multiple SNPs as instruments and multiple gene expression traits as exposures, simultaneously. Applied to 43 human phenotypes, it uncovers 3,913 putatively causal gene–trait associations, 36% of which have no genome-wide significant SNP nearby in previous GWAS. Using independent association summary statistics, we find that the majority of these loci were missed by GWAS due to power issues. Noteworthy among these links is educational attainment-associated BSCL2, known to carry mutations leading to a Mendelian form of encephalopathy. We also find pleiotropic causal effects suggestive of mechanistic connections. TWMR better accounts for pleiotropy and has the potential to identify biological mechanisms underlying complex traits

A deep learning system accurately classifies primary and metastatic cancers using passenger mutation patterns

In cancer, the primary tumour's organ of origin and histopathology are the strongest determinants of its clinical behaviour, but in 3% of cases a patient presents with a metastatic tumour and no obvious primary. Here,as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, we train a deep learning classifier to predict cancer type based on patterns of somatic passenger mutations detected in whole genome sequencing (WGS) of 2606 tumours representing 24 common cancer types produced by the PCAWG Consortium. Our classifier achieves an accuracy of 91% on held-out tumor samples and 88% and 83% respectively on independent primary and metastatic samples, roughly double the accuracy of trained pathologists when presented with a metastatic tumour without knowledge of the primary. Surprisingly, adding information on driver mutations reduced accuracy. Our results have clinical applicability, underscore how patterns of somatic passenger mutations encode the state of the cell of origin, and can inform future strategies to detect the source of circulating tumour DNA