scholarly journals Rare variant pathogenicity triage and inclusion of synonymous variants improves analysis of disease associations

2018 ◽  
Author(s):  
Ridge Dershem ◽  
Raghu P.R. Metpally ◽  
Kirk Jeffreys ◽  
Sarathbabu Krishnamurthy ◽  
Diane T. Smelser ◽  
...  
Keyword(s):  
Rare Variant ◽  
Functional Characterization ◽  
Data Sets ◽  
Common Variants ◽  
Loss Of Function ◽  
Altered Expression ◽  
Missense Variants ◽  
Association Testing ◽  
Disease Associations ◽  
Causes Of Disease

AbstractMany G protein-coupled receptors (GPCRs) lack common variants that lead to reproducible genome-wide disease associations. Here we used rare variant approaches to assess the disease associations of 85 orphan or understudied GPCRs in an unselected cohort of 51,289 individuals. Rare loss-of-function variants, missense variants predicted to be pathogenic or likely pathogenic, and a subset of rare synonymous variants were used as independent data sets for sequence kernel association testing (SKAT). Strong, phenome-wide disease associations shared by two or more variant categories were found for 39% of the GPCRs. Validating the bioinformatics and SKAT analyses, functional characterization of rare missense and synonymous variants of GPR39, a Family A GPCR, showed altered expression and/or Zn2+-mediated signaling for members of both variant classes. Results support the utility of rare variant analyses for identifying disease associations for genes that lack common variants, while also highlighting the functional importance of rare synonymous variants.Author summaryRare variant approaches have emerged as a viable way to identify disease associations for genes without clinically important common variants. Rare synonymous variants are generally considered benign. We demonstrate that rare synonymous variants represent a potentially important dataset for deriving disease associations, here applied to analysis of a set of orphan or understudied GPCRs. Synonymous variants yielded disease associations in common with loss-of-function or missense variants in the same gene. We rationalize their associations with disease by confirming their impact on expression and agonist activation of a representative example, GPR39. This study highlights the importance of rare synonymous variants in human physiology, and argues for their routine inclusion in any comprehensive analysis of genomic variants as potential causes of disease.

Abstract 97: Genotype to Phenotype: Function of Common Noncoding and Rare Coding Variants In ANGPTL3

2017 ◽  
Vol 37 (suppl_1) ◽  
Author(s):  
Xiao Wang ◽  
Avanthi Raghavan ◽  
A. Christina Vourakis ◽  
Alexandra E Sperry ◽  
Wenjun Li ◽  
...  
Keyword(s):  
Knockout Mice ◽  
Association Studies ◽  
Functional Characterization ◽  
Genome Wide Association Studies ◽  
Missense Mutations ◽  
Common Variants ◽  
Loss Of Function ◽  
Wild Type ◽  
Enhancer Activity ◽  
Missense Variants

Human genetics studies have demonstrated a strong link between ANGPTL3 , which encodes lipoprotein lipase inhibitor Angiopoietin-like 3, and blood lipid phenotypes. Rare nonsense ANGPTL3 mutations were identified in patients with familial combined hypolipidemia, while common variants at the ANGPTL3 locus have been found by genome-wide association studies (GWASs) to associate with lower triglycerides (TGs) and low-density lipoprotein cholesterol. In light of the seemingly favorable clinical consequences of ANGPTL3 deficiency, we established an experimental framework to identify (1) causal common variants that regulate ANGPTL3 expression and (2) rare missense mutations that disrupt ANGPTL3 function. Using massively parallel reporter assays, we profiled the regulatory activity of all the common variants linked ( r 2 ≥ 0.5) to the lead GWAS SNP in the ANGPTL3 locus and found that rs10889356 demonstrated significant allele-specific enhancer activity. To validate this finding, we used CRISPR-Cas9 to alter the SNP in a human pluripotent stem cell line. When differentiated into hepatocytes, altered cells displayed a 67% increase in ANGPTL3 expression ( n = 4 wild-type and 4 mutant clones, P = 0.007). CRISPR interference using each of three guide RNAs targeting the SNP in HepG2 cells also substantially increased ANGPTL3 expression. These findings support rs10889356- ANGPTL3 as a causal SNP-gene set. Next, we examined the coding regions of ANGPTL3 in 20,000 sequenced individuals and sought to experimentally define rare missense variants using a mouse model. We used CRISPR-Cas9 to generate Angptl3 knockout mice, which exhibited decreased TG (61%, P < 0.001) and decreased cholesterol (31%, P < 0.002). We reconstituted the knockout mice to normal expression levels with adenoviruses expressing either wild-type ANGPTL3 or missense variant ANGPTL3 . So far we have assessed 28 rare missense variants computationally predicted to be deleterious, of which only 10—D42N, K58E, S117P, P264S, Q286H, L315S, L360Q, T383I, T383S, and Y417C—were validated as loss-of-function (conferring <25% of wild-type activity as assessed by changes in both TG and cholesterol levels), underscoring the need for functional characterization of variants of uncertain significance.

scholarly journals Genome-wide rare variant analysis for thousands of phenotypes in 54,000 exomes

2019 ◽  
Author(s):  
Elizabeth T. Cirulli ◽  
Simon White ◽  
Robert W. Read ◽  
Gai Elhanan ◽  
William J Metcalf ◽  
...  
Keyword(s):  
Rare Variant ◽  
Large Scale ◽  
Rare Variants ◽  
Sequence Data ◽  
Statistical Significance ◽  
European Ancestry ◽  
Hair Color ◽  
Common Variants ◽  
Loss Of Function ◽  
Test Statistic

Defining the effects that rare variants can have on human phenotypes is essential to advancing our understanding of human health and disease. Large-scale human genetic analyses have thus far focused on common variants, but the development of large cohorts of deeply phenotyped individuals with exome sequence data has now made comprehensive analyses of rare variants possible. We analyzed the effects of rare (MAF<0.1%) variants on 3,166 phenotypes in 40,468 exome-sequenced individuals from the UK Biobank and performed replication as well as meta-analyses with 1,067 phenotypes in 13,470 members of the Healthy Nevada Project (HNP) cohort who underwent Exome+ sequencing at Helix. Our analyses of non-benign coding and loss of function (LoF) variants identified 78 gene-based associations that passed our statistical significance threshold (p<5×10-9). These are associations in which carrying any rare coding or LoF variant in the gene is associated with an enrichment for a specific phenotype, as opposed to GWAS-based associations of strictly single variants. Importantly, our results do not suffer from the test statistic inflation that is often seen with rare variant analyses of biobank-scale data because of our rare variant-tailored methodology, which includes a step that optimizes the carrier frequency threshold for each phenotype based on prevalence. Of the 47 discovery associations whose phenotypes were represented in the replication cohort, 98% showed effects in the expected direction, and 45% attained formal replication significance (p<0.001). Six additional significant associations were identified in our meta-analysis of both cohorts. Among the results, we confirm known associations of PCSK9 and APOB variation with LDL levels; we extend knowledge of variation in the TYRP1 gene, previously associated with blonde hair color only in Solomon Islanders to blonde hair color in individuals of European ancestry; we show that PAPPA, a gene in which common variants had previously associated with height via GWAS, contains rare variants that decrease height; and we make the novel discovery that STAB1 variation is associated with blood flow in the brain. Our results are available for download and interactive browsing in an app (https://ukb.research.helix.com). This comprehensive analysis of the effects of rare variants on human phenotypes marks one of the first steps in the next big phase of human genetics, where large, deeply phenotyped cohorts with next generation sequence data will elucidate the effects of rare variants.

scholarly journals Excess of singleton loss-of-function variants in Parkinson’s disease contributes to genetic risk

2020 ◽  
Vol 57 (9) ◽  
pp. 617-623 ◽  
Author(s):  
Dheeraj Reddy Bobbili ◽  
Peter Banda ◽  
Rejko Krüger ◽  
Patrick May
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Rare Variant ◽  
Prediction Models ◽  
Area Under The Curve ◽  
Classification Model ◽  
Polygenic Risk Score ◽  
Disease Prediction ◽  
Common Variants ◽  
Loss Of Function

BackgroundParkinson’s disease (PD) is a neurodegenerative disorder with complex genetic architecture. Besides rare mutations in high-risk genes related to monogenic familial forms of PD, multiple variants associated with sporadic PD were discovered via association studies.MethodsWe studied the whole-exome sequencing data of 340 PD cases and 146 ethnically matched controls from the Parkinson’s Progression Markers Initiative (PPMI) and performed burden analysis for different rare variant classes. Disease prediction models were built based on clinical, non-clinical and genetic features, including both common and rare variants, and two machine learning methods.ResultsWe observed a significant exome-wide burden of singleton loss-of-function variants (corrected p=0.037). Overall, no exome-wide burden of rare amino acid changing variants was detected. Finally, we built a disease prediction model combining singleton loss-of-function variants, a polygenic risk score based on common variants, and family history of PD as features and reached an area under the curve of 0.703 (95% CI 0.698 to 0.708). By incorporating a rare variant feature, our model increased the performance of the state-of-the-art classification model for the PPMI dataset, which reached an area under the curve of 0.639 based on common variants alone.ConclusionThe main finding of this study is to highlight the contribution of singleton loss-of-function variants to the complex genetics of PD and that disease risk prediction models combining singleton and common variants can improve models built solely on common variants.

scholarly journals MVP predicts the pathogenicity of missense variants by deep learning

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Hongjian Qi ◽  
Haicang Zhang ◽  
Yige Zhao ◽  
Chen Chen ◽  
John J. Long ◽  
...  
Keyword(s):  
Developmental Disorders ◽  
De Novo ◽  
Prediction Method ◽  
Genetic Effect ◽  
Missense Variant ◽  
Training Data ◽  
Data Sets ◽  
Loss Of Function ◽  
Missense Variants ◽  
Pathogenicity Prediction

AbstractAccurate pathogenicity prediction of missense variants is critically important in genetic studies and clinical diagnosis. Previously published prediction methods have facilitated the interpretation of missense variants but have limited performance. Here, we describe MVP (Missense Variant Pathogenicity prediction), a new prediction method that uses deep residual network to leverage large training data sets and many correlated predictors. We train the model separately in genes that are intolerant of loss of function variants and the ones that are tolerant in order to take account of potentially different genetic effect size and mode of action. We compile cancer mutation hotspots and de novo variants from developmental disorders for benchmarking. Overall, MVP achieves better performance in prioritizing pathogenic missense variants than previous methods, especially in genes tolerant of loss of function variants. Finally, using MVP, we estimate that de novo coding variants contribute to 7.8% of isolated congenital heart disease, nearly doubling previous estimates.

scholarly journals Functional Characterization of the Adenylyl Cyclase Genesgs-1by Analysis of a Mutational Spectrum inCaenorhabditis elegans

Genetics ◽  
2002 ◽  
Vol 161 (1) ◽  
pp. 133-142 ◽  
Author(s):  
Celine Moorman ◽  
Ronald H A Plasterk
Keyword(s):  
Life Span ◽  
Adenylyl Cyclase ◽  
Neuronal Degeneration ◽  
Functional Characterization ◽  
Adenylyl Cyclases ◽  
Loss Of Function ◽  
C Elegans ◽  
Larval Stages ◽  
Pharyngeal Pumping

AbstractThe sgs-1 (suppressor of activated Gαs) gene encodes one of the four adenylyl cyclases in the nematode C. elegans and is most similar to mammalian adenylyl cyclase type IX. We isolated a complete loss-of-function mutation in sgs-1 and found it to result in animals with retarded development that arrest in variable larval stages. sgs-1 mutant animals exhibit lethargic movement and pharyngeal pumping and (while not reaching adulthood) have a mean life span that is &gt;50% extended compared to wild type. An extensive set of reduction-of-function mutations in sgs-1 was isolated in a screen for suppressors of a neuronal degeneration phenotype induced by the expression of a constitutively active version of the heterotrimeric Gαs subunit of C. elegans. Although most of these mutations change conserved residues within the catalytic domains of sgs-1, mutations in the less-conserved transmembrane domains are also found. The sgs-1 reduction-of-function mutants are viable and have reduced locomotion rates, but do not show defects in pharyngeal pumping or life span.

scholarly journals Loss-of-function and missense variants in NSD2 cause decreased methylation activity and are associated with a distinct developmental phenotype

2021 ◽  
Author(s):  
Paolo Zanoni ◽  
Katharina Steindl ◽  
Deepanwita Sengupta ◽  
Pascal Joset ◽  
Angela Bahr ◽  
...  
Keyword(s):  
Loss Of Function ◽  
Mild Phenotype ◽  
Psychological Issues ◽  
Missense Variants ◽  
Mild Developmental Delay ◽  
Pathogenic Variants ◽  
In Silico Modeling ◽  
And Function ◽  
Methylation Activity

Abstract Purpose Despite a few recent reports of patients harboring truncating variants in NSD2, a gene considered critical for the Wolf–Hirschhorn syndrome (WHS) phenotype, the clinical spectrum associated with NSD2 pathogenic variants remains poorly understood. Methods We collected a comprehensive series of 18 unpublished patients carrying heterozygous missense, elongating, or truncating NSD2 variants; compared their clinical data to the typical WHS phenotype after pooling them with ten previously described patients; and assessed the underlying molecular mechanism by structural modeling and measuring methylation activity in vitro. Results The core NSD2-associated phenotype includes mostly mild developmental delay, prenatal-onset growth retardation, low body mass index, and characteristic facial features distinct from WHS. Patients carrying missense variants were significantly taller and had more frequent behavioral/psychological issues compared with those harboring truncating variants. Structural in silico modeling suggested interference with NSD2’s folding and function for all missense variants in known structures. In vitro testing showed reduced methylation activity and failure to reconstitute H3K36me2 in NSD2 knockout cells for most missense variants. Conclusion NSD2 loss-of-function variants lead to a distinct, rather mild phenotype partially overlapping with WHS. To avoid confusion for patients, NSD2 deficiency may be named Rauch–Steindl syndrome after the delineators of this phenotype.

scholarly journals 166 Functional characterization of missense variants in ABCC6, the gene responsible for pseudoxanthoma elasticum

2021 ◽  
Vol 141 (5) ◽  
pp. S29
Author(s):  
J. Huang ◽  
L. Kowal ◽  
J. Singh ◽  
A.E. Snook ◽  
J. Uitto ◽  
...  
Keyword(s):  
Functional Characterization ◽  
Pseudoxanthoma Elasticum ◽  
Missense Variants

scholarly journals Deciphering the Mounting Complexity of the p53 Regulatory Network in Correlation to Long Non-Coding RNAs (lncRNAs) in Ovarian Cancer

Cells ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 527 ◽  
Author(s):  
Sonali Pal ◽  
Manoj Garg ◽  
Amit Kumar Pandey
Keyword(s):  
Ovarian Cancer ◽  
Molecular Mechanisms ◽  
Human Cancer ◽  
Critical Role ◽  
Functional Characterization ◽  
Great Promise ◽  
Altered Expression ◽  
Disease Biology ◽  
Non Coding Rnas ◽  
Post Transcriptional Regulation

Amongst the various gynecological malignancies affecting female health globally, ovarian cancer is one of the predominant and lethal among all. The identification and functional characterization of long non-coding RNAs (lncRNAs) are made possible with the advent of RNA-seq and the advancement of computational logarithm in understanding human disease biology. LncRNAs can interact with deoxyribonucleic acid (DNA), ribonucleic acid (RNA), proteins and their combinations. Moreover, lncRNAs regulate orchestra of diverse functions including chromatin organization and transcriptional and post-transcriptional regulation. LncRNAs have conferred their critical role in key biological processes in human cancer including tumor initiation, proliferation, cell cycle, apoptosis, necroptosis, autophagy, and metastasis. The interwoven function of tumor-suppressor protein p53-linked lncRNAs in the ovarian cancer paradigm is of paramount importance. Several lncRNAs operate as p53 regulators or effectors and modulates a diverse array of functions either by participating in various signaling cascades or via interaction with different proteins. This review highlights the recent progress made in the identification of p53 associated lncRNAs while elucidating their molecular mechanisms behind the altered expression in ovarian cancer tumorigenesis. Moreover, the development of novel clinical and therapeutic strategies for targeting lncRNAs in human cancers harbors great promise.

scholarly journals Altered Expression of Peroxiredoxins in Mouse Model of Progressive Myoclonus Epilepsy upon LPS-Induced Neuroinflammation

Antioxidants ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 357
Author(s):  
Mojca Trstenjak Prebanda ◽  
Petra Matjan-Štefin ◽  
Boris Turk ◽  
Nataša Kopitar-Jerala
Keyword(s):  
Mouse Model ◽  
Redox Homeostasis ◽  
Underlying Mechanism ◽  
Loss Of Function ◽  
Altered Expression ◽  
Lps Challenge ◽  
Progressive Myoclonus Epilepsy ◽  
Myoclonus Epilepsy ◽  
The Brain ◽  
Deficient Mice

Stefin B (cystatin B) is an inhibitor of endo-lysosomal cysteine cathepsin, and the loss-of-function mutations in the stefin B gene were reported in patients with Unverricht–Lundborg disease (EPM1), a form of progressive myoclonus epilepsy. Stefin B-deficient mice, a mouse model of the disease, display key features of EPM1, including myoclonic seizures. Although the underlying mechanism is not yet completely clear, it was reported that the impaired redox homeostasis and inflammation in the brain contribute to the progression of the disease. In the present study, we investigated if lipopolysaccharide (LPS)-triggered neuroinflammation affected the protein levels of redox-sensitive proteins: thioredoxin (Trx1), thioredoxin reductase (TrxR), peroxiredoxins (Prxs) in brain and cerebella of stefin B-deficient mice. LPS challenge was found to result in a marked elevation of Trx1 and TrxR in the brain and cerebella of stefin B deficient mice, while Prx1 was upregulated only in cerebella after LPS challenge. Mitochondrial peroxiredoxin 3 (Prx3), was upregulated also in the cerebellar tissue lysates prepared from unchallenged stefin B deficient mice, while after LPS challenge Prx3 was upregulated in stefin B deficient brain and cerebella. Our results imply the role of oxidative stress in the progression of the disease.

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