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31
result(s) for
"Belbin, Gillian M."
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Rapid detection of identity-by-descent tracts for mega-scale datasets
by
Avery, Christy L.
,
Gignoux, Christopher R.
,
Shemirani, Ruhollah
in
631/114/2785
,
631/208/457
,
Algorithms
2021
The ability to identify segments of genomes identical-by-descent (IBD) is a part of standard workflows in both statistical and population genetics. However, traditional methods for finding local IBD across all pairs of individuals scale poorly leading to a lack of adoption in very large-scale datasets. Here, we present iLASH, an algorithm based on similarity detection techniques that shows equal or improved accuracy in simulations compared to current leading methods and speeds up analysis by several orders of magnitude on genomic datasets, making IBD estimation tractable for millions of individuals. We apply iLASH to the PAGE dataset of ~52,000 multi-ethnic participants, including several founder populations with elevated IBD sharing, identifying IBD segments in ~3 minutes per chromosome compared to over 6 days for a state-of-the-art algorithm. iLASH enables efficient analysis of very large-scale datasets, as we demonstrate by computing IBD across the UK Biobank (~500,000 individuals), detecting 12.9 billion pairwise connections.
Traditional methods to identify genomic regions identical-by-descent (IBD) do not scale well to biobank-level datasets. Here, the authors describe a new IBD algorithm, iLASH, which uses LocAlity-Sensitive Hashing to provide rapid IBD estimation when applied to the PAGE and UK Biobank datasets.
Journal Article
Exome sequencing reveals a high prevalence of BRCA1 and BRCA2 founder variants in a diverse population-based biobank
2019
Background
Pathogenic variants in
BRCA1
and
BRCA2
(
BRCA1/2
) lead to increased risk of breast, ovarian, and other cancers, but most variant-positive individuals in the general population are unaware of their risk, and little is known about prevalence in non-European populations. We investigated
BRCA1/2
prevalence and impact in the electronic health record (EHR)-linked Bio
Me
Biobank in New York City.
Methods
Exome sequence data from 30,223 adult Bio
Me
participants were evaluated for pathogenic variants in
BRCA1/2
. Prevalence estimates were made in population groups defined by genetic ancestry and self-report. EHR data were used to evaluate clinical characteristics of variant-positive individuals.
Results
There were 218 (0.7%) individuals harboring expected pathogenic variants, resulting in an overall prevalence of 1 in 139. The highest prevalence was in individuals with Ashkenazi Jewish (AJ; 1 in 49), Filipino and other Southeast Asian (1 in 81), and non-AJ European (1 in 103) ancestry. Among 218 variant-positive individuals, 112 (51.4%) harbored known founder variants: 80 had AJ founder variants (
BRCA1
c.5266dupC and c.68_69delAG, and
BRCA2
c.5946delT), 8 had a Puerto Rican founder variant (
BRCA2
c.3922G>T), and 24 had one of 19 other founder variants. Non-European populations were more likely to harbor
BRCA1/2
variants that were not classified in ClinVar or that had uncertain or conflicting evidence for pathogenicity (uncertain/conflicting). Within mixed ancestry populations, such as Hispanic/Latinos with genetic ancestry from Africa, Europe, and the Americas, there was a strong correlation between the proportion of African genetic ancestry and the likelihood of harboring an uncertain/conflicting variant. Approximately 28% of variant-positive individuals had a personal history, and 45% had a personal or family history of
BRCA1/2-
associated cancers. Approximately 27% of variant-positive individuals had prior clinical genetic testing for
BRCA1/2
. However, individuals with AJ founder variants were twice as likely to have had a clinical test (39%) than those with other pathogenic variants (20%).
Conclusions
These findings deepen our knowledge about
BRCA1/2
variants and associated cancer risk in diverse populations, indicate a gap in knowledge about potential cancer-related variants in non-European populations, and suggest that genomic screening in diverse patient populations may be an effective tool to identify at-risk individuals.
Journal Article
A positively selected FBN1 missense variant reduces height in Peruvian individuals
2020
On average, Peruvian individuals are among the shortest in the world
1
. Here we show that Native American ancestry is associated with reduced height in an ethnically diverse group of Peruvian individuals, and identify a population-specific, missense variant in the
FBN1
gene (E1297G) that is significantly associated with lower height. Each copy of the minor allele (frequency of 4.7%) reduces height by 2.2 cm (4.4 cm in homozygous individuals). To our knowledge, this is the largest effect size known for a common height-associated variant.
FBN1
encodes the extracellular matrix protein fibrillin 1, which is a major structural component of microfibrils. We observed less densely packed fibrillin-1-rich microfibrils with irregular edges in the skin of individuals who were homozygous for G1297 compared with individuals who were homozygous for E1297. Moreover, we show that the E1297G locus is under positive selection in non-African populations, and that the E1297 variant shows subtle evidence of positive selection specifically within the Peruvian population. This variant is also significantly more frequent in coastal Peruvian populations than in populations from the Andes or the Amazon, which suggests that short stature might be the result of adaptation to factors that are associated with the coastal environment in Peru.
In an ethnically diverse group of Peruvian individuals, the population-specific, missense variant in
FBN1
(E1297G) is associated with lower height and shows evidence of positive selection within the Peruvian population.
Journal Article
An integrative multiomic network model links lipid metabolism to glucose regulation in coronary artery disease
2021
Elevated plasma cholesterol and type 2 diabetes (T2D) are associated with coronary artery disease (CAD). Individuals treated with cholesterol-lowering statins have increased T2D risk, while individuals with hypercholesterolemia have reduced T2D risk. We explore the relationship between lipid and glucose control by constructing network models from the STARNET study with sequencing data from seven cardiometabolic tissues obtained from CAD patients during coronary artery by-pass grafting surgery. By integrating gene expression, genotype, metabolomic, and clinical data, we identify a glucose and lipid determining (GLD) regulatory network showing inverse relationships with lipid and glucose traits. Master regulators of the GLD network also impact lipid and glucose levels in inverse directions. Experimental inhibition of one of the GLD network master regulators, lanosterol synthase (
LSS
), in mice confirms the inverse relationships to glucose and lipid levels as predicted by our model and provides mechanistic insights.
Some cholesterol-lowering drugs can increase the risk of type 2 diabetes, but the mechanism behind this is not fully understood. Here the authors show that there is a single genetic regulatory module that influences both cholesterol levels and glucose levels, providing a link between cholesterol levels and diabetes.
Journal Article
Implementing genomic screening in diverse populations
2021
Background
Population-based genomic screening has the predicted ability to reduce morbidity and mortality associated with medically actionable conditions. However, much research is needed to develop standards for genomic screening and to understand the perspectives of people offered this new testing modality. This is particularly true for non-European ancestry populations who are vastly underrepresented in genomic medicine research. Therefore, we implemented a pilot genomic screening program in the Bio
Me
Biobank in New York City, where the majority of participants are of non-European ancestry.
Methods
We initiated genomic screening for well-established genes associated with hereditary breast and ovarian cancer syndrome (HBOC), Lynch syndrome (LS), and familial hypercholesterolemia (FH). We evaluated and included an additional gene (
TTR
) associated with hereditary transthyretin amyloidosis (hATTR), which has a common founder variant in African ancestry populations. We evaluated the characteristics of 74 participants who received results associated with these conditions. We also assessed the preferences of 7461 newly enrolled Bio
Me
participants to receive genomic results.
Results
In the pilot genomic screening program, 74 consented participants received results related to HBOC (
N
= 26), LS (
N
= 6), FH (
N
= 8), and hATTR (
N
= 34). Thirty-three of 34 (97.1%) participants who received a result related to hATTR were self-reported African American/African (AA) or Hispanic/Latinx (HL), compared to 14 of 40 (35.0%) participants who received a result related to HBOC, LS, or FH. Among the 7461 participants enrolled after the Bio
Me
protocol modification to allow the return of genomic results, 93.4% indicated that they would want to receive results. Younger participants, women, and HL participants were more likely to opt to receive results.
Conclusions
The addition of
TTR
to a pilot genomic screening program meant that we returned results to a higher proportion of AA and HL participants, in comparison with genes traditionally included in genomic screening programs in the USA. We found that the majority of participants in a multi-ethnic biobank are interested in receiving genomic results for medically actionable conditions. These findings increase knowledge about the perspectives of diverse research participants on receiving genomic results and inform the broader implementation of genomic medicine in underrepresented patient populations.
Journal Article
Causal effects on complex traits are similar for common variants across segments of different continental ancestries within admixed individuals
by
Rasmussen-Torvik, Laura J.
,
Pasaniuc, Bogdan
,
Bhattacharya, Arjun
in
631/114
,
631/208/205/2138
,
631/208/457
2023
Individuals of admixed ancestries (for example, African Americans) inherit a mosaic of ancestry segments (local ancestry) originating from multiple continental ancestral populations. This offers the unique opportunity of investigating the similarity of genetic effects on traits across ancestries within the same population. Here we introduce an approach to estimate correlation of causal genetic effects (
r
admix
) across local ancestries and analyze 38 complex traits in African-European admixed individuals (
N
= 53,001) to observe very high correlations (meta-analysis
r
admix
= 0.95, 95% credible interval 0.93–0.97), much higher than correlation of causal effects across continental ancestries. We replicate our results using regression-based methods from marginal genome-wide association study summary statistics. We also report realistic scenarios where regression-based methods yield inflated heterogeneity-by-ancestry due to ancestry-specific tagging of causal effects, and/or polygenicity. Our results motivate genetic analyses that assume minimal heterogeneity in causal effects by ancestry, with implications for the inclusion of ancestry-diverse individuals in studies.
This analysis of individuals of admixed genetic ancestries suggests that complex trait causal variant effect sizes are, by and large, similar across ancestries, and discusses the implications for the study of these and other diverse populations.
Journal Article
Integrative analysis of loss-of-function variants in clinical and genomic data reveals novel genes associated with cardiovascular traits
by
Amadori, Letizia
,
Shameer, Khader
,
Readhead, Ben
in
Anticholesteremic agents
,
Antilipemic agents
,
Atherosclerosis
2019
Background
Genetic loss-of-function variants (LoFs) associated with disease traits are increasingly recognized as critical evidence for the selection of therapeutic targets. We integrated the analysis of genetic and clinical data from 10,511 individuals in the Mount Sinai Bio
Me
Biobank to identify genes with loss-of-function variants (LoFs) significantly associated with cardiovascular disease (CVD) traits, and used RNA-sequence data of seven metabolic and vascular tissues isolated from 600 CVD patients in the Stockholm-Tartu Atherosclerosis Reverse Network Engineering Task (STARNET) study for validation. We also carried out in vitro functional studies of several candidate genes, and in vivo studies of one gene.
Results
We identified LoFs in 433 genes significantly associated with at least one of 10 major CVD traits. Next, we used RNA-sequence data from the STARNET study to validate 115 of the 433 LoF harboring-genes in that their expression levels were concordantly associated with corresponding CVD traits. Together with the documented hepatic lipid-lowering gene,
APOC3,
the expression levels of six additional liver LoF-genes were positively associated with levels of plasma lipids in STARNET. Candidate LoF-genes were subjected to gene silencing in HepG2 cells with marked overall effects on cellular LDLR, levels of triglycerides and on secreted APOB100 and PCSK9. In addition, we identified novel LoFs in
DGAT2
associated with lower plasma cholesterol and glucose levels in Bio
Me
that were also confirmed in STARNET, and showed a selective DGAT2-inhibitor in C57BL/6 mice not only significantly lowered fasting glucose levels but also affected body weight.
Conclusion
In sum, by integrating genetic and electronic medical record data, and leveraging one of the world’s largest human RNA-sequence datasets (STARNET), we identified known and novel CVD-trait related genes that may serve as targets for CVD therapeutics and as such merit further investigation.
Journal Article
Multiscale causal networks identify VGF as a key regulator of Alzheimer’s disease
2020
Though discovered over 100 years ago, the molecular foundation of sporadic Alzheimer’s disease (AD) remains elusive. To better characterize the complex nature of AD, we constructed multiscale causal networks on a large human AD multi-omics dataset, integrating clinical features of AD, DNA variation, and gene- and protein-expression. These probabilistic causal models enabled detection, prioritization and replication of high-confidence master regulators of AD-associated networks, including the top predicted regulator, VGF. Overexpression of neuropeptide precursor VGF in 5xFAD mice partially rescued beta-amyloid-mediated memory impairment and neuropathology. Molecular validation of network predictions downstream of VGF was also achieved in this AD model, with significant enrichment for homologous genes identified as differentially expressed in 5xFAD brains overexpressing VGF. Our findings support a causal role for VGF in protecting against AD pathogenesis and progression.
To investigate the molecular foundation of sporadic Alzheimer’s disease (AD), Beckmann et al. constructed multiscale causal networks on a large human AD multi-omics dataset, detecting AD-associated networks and their top predicted regulator, VGF, with extensive validation in the 5xFAD mouse model.
Journal Article
CDH1 pathogenic variants and cancer risk in an unselected patient population
2022
CDH1 pathogenic variants confer a markedly elevated lifetime risk of developing diffuse gastric cancer (DGC) and lobular breast cancer (LBC). The aim of this study was to evaluate the prevalence and clinical impact of CDH1 pathogenic variants in the unselected and ancestrally diverse BioMe Biobank. We evaluated exome sequence data from 30,223 adult BioMe participants to identify CDH1 positive individuals, defined as those harboring a variant previously classified as pathogenic or likely pathogenic or a predicted loss-of-function variant in CDH1. We reviewed electronic health records and BioMe enrollment surveys for personal and family history of malignancy and evidence of prior clinical genetic testing. Using a genomics-first approach, we identified 6 CDH1 positive individuals in BioMe (~ 1 in 5000). CDH1 positive individuals had a median age of 42 years (range 35–62 years), all were non-European by self-report, and one was female. None had evidence of either a personal or family history of DGC or LBC. Our findings suggest a low risk of DGC and LBC in unselected patients harboring a pathogenic variant in CDH1. Knowledge of CDH1-related cancer risk in individuals with no personal or family history may better inform surveillance and prophylactic measures.
Journal Article