Gibran Hemani
A5016515762- Genetic Associations and Epidemiology
- Genetic Mapping and Diversity in Plants and Animals
- Epigenetics and DNA Methylation
- Genetic and phenotypic traits in livestock
- Birth, Development, and Health
- Bioinformatics and Genomic Networks
- Health, Environment, Cognitive Aging
- Genetic Syndromes and Imprinting
- Cognitive Abilities and Testing
- Advanced Causal Inference Techniques
- Gene expression and cancer classification
- Nutrition, Genetics, and Disease
- COVID-19 epidemiological studies
- Liver Disease Diagnosis and Treatment
- COVID-19 and Mental Health
- Tryptophan and brain disorders
- Genomics and Rare Diseases
- Folate and B Vitamins Research
- RNA modifications and cancer
- Cancer-related molecular mechanisms research
- Lipid metabolism and disorders
- Fatty Acid Research and Health
- Genetics and Neurodevelopmental Disorders
- Cleft Lip and Palate Research
- BRCA gene mutations in cancer
University of Bristol
2016-2025
MRC Epidemiology Unit
2016-2025
Medical Research Council
2016-2025
MRC Integrative Epidemiology Unit
2015-2025
University Medical Center Groningen
2022-2024
University of Groningen
2024
Bristol Regional Medical Center
2024
Massachusetts General Hospital
2024
University Hospitals Bristol NHS Foundation Trust
2019-2024
NIHR Bristol Biomedical Research Centre
2024
Results from genome-wide association studies (GWAS) can be used to infer causal relationships between phenotypes, using a strategy known as 2-sample Mendelian randomization (2SMR) and bypassing the need for individual-level data. However, 2SMR methods are evolving rapidly GWAS results often insufficiently curated, undermining efficient implementation of approach. We therefore developed MR-Base ( http://www.mrbase.org ): platform that integrates curated database complete (no restrictions...
Inference about the causal structure that induces correlations between two traits can be achieved by combining genetic associations with a mediation-based approach, as is done in inference test (CIT). However, we show measurement error phenotypes lead to CIT inferring wrong direction, and increasing sample sizes has adverse effect of confidence answer. This problem likely general other approaches. Here introduce an extension Mendelian randomisation, method uses instrumentation framework,...
LD score regression is a reliable and efficient method of using genome-wide association study (GWAS) summary-level results data to estimate the SNP heritability complex traits diseases, partition this into functional categories, genetic correlation between different phenotypes. Because relies on summary level data, computationally tractable even for very large sample sizes. However, publicly available GWAS are typically stored in databases have formats, making it difficult apply correlations...
Abstract Numerous observational studies have attempted to identify risk factors for infection with SARS-CoV-2 and COVID-19 disease outcomes. Studies used datasets sampled from patients admitted hospital, people tested active infection, or who volunteered participate. Here, we highlight the challenge of interpreting evidence such non-representative samples. Collider bias can induce associations between two more variables which affect likelihood an individual being sampled, distorting these in...
Abstract Data generated by genome-wide association studies (GWAS) are growing fast with the linkage of biobank samples to health records, and expanding capture high-dimensional molecular phenotypes. However utility these efforts can only be fully realised if their complete results collected from heterogeneous sources formats, harmonised made programmatically accessible. Here we present OpenGWAS database, an open source, access, scalable high-performance cloud-based data infrastructure that...
Estimation of narrow-sense heritability, h2, from genome-wide SNPs genotyped in unrelated individuals has recently attracted interest and offers several advantages over traditional pedigree-based methods. With the use this approach, it been estimated that half heritability human height can be attributed to ∼300,000 on a genotyping array. In comparison, only 5%–10% explained by reaching significance. We investigated via simulation validity key assumptions underpinning mixed-model analysis...
Mendelian randomization (MR) is a method of exploiting genetic variation to unbiasedly estimate causal effect in presence unmeasured confounding. MR being widely used epidemiology and other related areas population science. In this paper, we study statistical inference the increasingly popular two-sample summary-data design. We show linear model for observed associations approximately holds wide variety settings when all variants satisfy exclusion restriction assumption, or terms, there no...
The influence of genetic variation on complex diseases is potentially mediated through a range highly dynamic epigenetic processes exhibiting temporal during development and later life. Here we present catalogue the influences DNA methylation (methylation quantitative trait loci (mQTL)) at five different life stages in human blood: children birth, childhood, adolescence their mothers pregnancy middle age. We show that effects are stable across course developmental change contribution to...
Summary While many disease-associated variants have been identified through genome-wide association studies, their downstream molecular consequences remain unclear. To identify these effects, we performed cis- and trans-expression quantitative trait locus (eQTL) analysis in blood from 31,684 individuals the eQTLGen Consortium. We observed that cis -eQTLs can be detected for 88% of studied genes, but they a different genetic architecture compared to variants, limiting our ability use pinpoint...
Abstract Background Smoking prevalence is higher amongst individuals with schizophrenia and depression compared the general population. Mendelian randomisation (MR) can examine whether this association causal using genetic variants identified in genome-wide studies (GWAS). Methods We conducted two-sample MR to explore bi-directional effects of smoking on depression. For behaviour, we used (1) initiation GWAS from GSCAN consortium (2) our own lifetime behaviour (which captures duration,...
The causal direction and magnitude of the association between telomere length incidence cancer non-neoplastic diseases is uncertain owing to susceptibility observational studies confounding reverse causation.
We have recently developed analysis methods (GREML) to estimate the genetic variance of a complex trait/disease and correlation between two traits/diseases using genome-wide single nucleotide polymorphism (SNP) data in unrelated individuals. Here we use analytical derivations simulations quantify sampling proportion phenotypic captured by all SNPs for quantitative traits case-control studies. also derive approximate bivariate analysis, when are either measured on same or different show that...