scholarly journals Pathogenicity of De Novo Rare Variants

2017 ◽  
Vol 10 (6) ◽  
Author(s):  
Arya Mani
Keyword(s):  
Rare Variants ◽  
De Novo

Abstract 15169: De Novo Variants of USP10 in Early Onset Bicuspid Aortic Valve Disease

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Siddharth K Prakash ◽  
Angela T Yetman ◽  
Hector I Michelena ◽  
Malenka M Bissell ◽  
Yuli Y Kim ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Bicuspid Aortic Valve ◽  
Early Onset ◽  
Rare Variants ◽  
De Novo ◽  
Late Onset ◽  
Copy Number Variants ◽  
Aortic Aneurysms ◽  
Thoracic Aortic Aneurysms ◽  
Aortic Dissections

Introduction: Bicuspid Aortic Valve (BAV), the most common congenital heart defect, is a major cause of aortic regurgitation or stenosis requiring valve replacement and thoracic aortic aneurysms predisposing to acute aortic dissections (TAD). The spectrum of BAV ranges from severe early onset valve and aortic complications to sporadic late onset disease. Hypothesis: Early onset BAV (EBAV) cases with valve or aortic complications that require intervention prior to age 30 are enriched for rare genetic variants that cause BAV and TAD. Methods: We performed whole exome sequencing of 147 EBAV cases in 141 families who were enrolled in the UTHealth Bicuspid Aortic Valve Research Registry. Candidate variants in the EBAV cohort (26% female, mean age 18, 44% with TAD) were compared to unselected controls from the Genome Aggregation Database (gnoMAD) and the Database of Genotypes and Phenotypes (dbGAP). We considered variants with minor allele frequencies (MAF) < 1%, Combined Annotation Dependent Depletion (CADD) scores > 25, and damaging (Polyphen-2) or deleterious (SIFT) functional prediction scores. Genomic copy number variants (CNVs) were detected using CoNIFER and prioritized when deletions involved genes with probability of loss intolerance (pLI) > 0.9. Variants were validated using quantitative PCR or Sanger sequencing. Results: We identified 6 rare variants of USP10 in 6 EBAV families (4% of cohort): 4 CNVs (2 duplications and 2 deletions) that are rare in dbGAP controls (4 in 15,414) and 2 deleterious rare missense variants (MAF<5x10 -5 in gnoMAD). Two of the 4 CNVs were de novo events in trios. In contrast, rare deleterious variants of the known causal BAV genes NOTCH1 (1), ROBO4 (1), GATA4 (1), GATA5 (1), and SMAD6 (4) were found in 7 total families. USP10 encodes a ubiquitin peptidase that is required for endothelial Notch signaling during vascular development. Conclusions: We identified rare and de novo variants of USP10 that implicate USP10 as a new candidate gene for BAV.

scholarly journals A Systematic Review on Extreme Phenotype Strategies to Search for Rare Variants in Genetic Studies of Complex Disorders

2020 ◽  
Author(s):  
Sana Amanat ◽  
Teresa Requena ◽  
Jose Antonio Lopez-Escamez
Keyword(s):  
Systematic Review ◽  
Candidate Genes ◽  
Rare Variants ◽  
De Novo ◽  
Complex Diseases ◽  
De Novo Mutations ◽  
Genetic Studies ◽  
Complex Disorders ◽  
Extreme Phenotype ◽  
Age Related

Exome sequencing has been commonly used in rare diseases by selecting multiplex families or singletons with an extreme phenotype (EP) to search for rare variants in coding regions. The EP strategy covers both extreme ends of a disease spectrum and it has been also used to investigate the contribution of rare variants to heritability in complex clinical traits. We have conducted a systematic review to find evidence supporting the use of EP strategies to search for rare variants in genetic studies of complex diseases, to highlight the contribution of rare variation to the genetic structure of multiallelic conditions. After performing the quality assessment of the retrieved records, we selected 19 genetic studies considering EP to demonstrate genetic association. All the studies successfully identified several rare variants, de novo mutations and many novel candidate genes were also identified by selecting an EP. There is enough evidence to support that the EP approach in patients with an early onset of the disease can contribute to the identification of rare variants in candidate genes or pathways involved in complex diseases. EP patients may contribute to a better understanding of the underlying genetic architecture of common heterogeneous disorders such as tinnitus or age-related hearing loss.

scholarly journals Rare variants in the genetic background modulate the expressivity of neurodevelopmental disorders

2018 ◽  
Author(s):  
Lucilla Pizzo ◽  
Matthew Jensen ◽  
Andrew Polyak ◽  
Jill A. Rosenfeld ◽  
Katrin Mannik ◽  
...  
Keyword(s):  
Family History ◽  
Genetic Background ◽  
Rare Variants ◽  
De Novo ◽  
Genetic Diagnosis ◽  
Clinical Information ◽  
Disease Genes ◽  
Complete Evaluation ◽  
Rare Cnvs ◽  
Complex Disorders

AbstractPurposeTo assess the contribution of rare variants in the genetic background towards variability of neurodevelopmental phenotypes in individuals with rare copy-number variants (CNVs) and gene-disruptive mutations.MethodsWe analyzed quantitative clinical information, exome-sequencing, and microarray data from 757 probands and 233 parents and siblings who carry disease-associated mutations.ResultsThe number of rare secondary mutations in functionally intolerant genes (second-hits) correlated with the expressivity of neurodevelopmental phenotypes in probands with 16p12.1 deletion (n=23, p=0.004) and in probands with autism carrying gene-disruptive mutations (n=184, p=0.03) compared to their carrier family members. Probands with 16p12.1 deletion and a strong family history presented more severe clinical features (p=0.04) and higher burden of second-hits compared to those with mild/no family history (p=0.001). The number of secondary variants also correlated with the severity of cognitive impairment in probands carrying pathogenic rare CNVs (n=53) or de novo mutations in disease genes (n=290), and negatively correlated with head size among 80 probands with 16p11.2 deletion. These second-hits involved known disease-associated genes such as SETD5, AUTS2, and NRXN1, and were enriched for genes affecting cellular and developmental processes.ConclusionAccurate genetic diagnosis of complex disorders will require complete evaluation of the genetic background even after a candidate gene mutation is identified.

scholarly journals Nearly Half of TP53 Germline Variants Predicted To Be Pathogenic in Patients With Osteosarcoma Are De Novo: A Report From the Children’s Oncology Group

2020 ◽  
pp. 1187-1195
Author(s):  
Brandon J. Diessner ◽  
Nathan Pankratz ◽  
Anthony J. Hooten ◽  
Lisa Mirabello ◽  
Aaron L. Sarver ◽  
...  
Keyword(s):  
Pediatric Patients ◽  
Rare Variants ◽  
De Novo ◽  
Phase 1 ◽  
Control Measures ◽  
Fisher Exact Test ◽  
Exact Test ◽  
Whole Exome ◽  
History Of ◽  
De Novo Variant

PURPOSE To ascertain the prevalence of recurrent de novo variants among 240 pediatric patients with osteosarcoma (OS; age < 20 years) unselected for family history of cancer. METHODS The identification of de novo variants was implemented in 2 phases. In the first, we identified genes with a rare (minor allele frequency < 0.01) de novo variant in > 1 of the 95 case-parent trios examined by whole-exome sequencing (WES) who passed quality control measures. In phase 2, 145 additional patients with OS were evaluated by targeted sequencing to identify rare de novo variants in genes nominated from phase 1. Recurrent rare variants identified from phase 1 and 2 were verified as either de novo or inherited by Sanger sequencing of affected patients and their parents. Categorical and continuous data were analyzed using Fisher exact test and t tests, respectively. RESULTS Among 95 case-parent trios who underwent WES, we observed 61 de novo variants in 60 genes among 47 patients, with TP53 identified as the only gene with a pathogenic or likely pathogenic (P/LP) de novo variant in more than one case-parent trio. Among all 240 patients with OS, 13 (5.4%) harbored a P/LP TP53 germline variant, of which 6 (46.2%) were confirmed to be de novo. CONCLUSION Apart from TP53, we did not observe any other recurrent de novo P/LP variants in the case-parent trios, suggesting that new mutations in other genes are not a frequent cause of pediatric OS. That nearly half of P/LP TP53 variants in our sample were de novo suggests universal screening for germline TP53 P/LP variants among pediatric patients with OS should be considered.

scholarly journals A Systematic Review of Extreme Phenotype Strategies to Search for Rare Variants in Genetic Studies of Complex Disorders

Genes ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 987
Author(s):  
Sana Amanat ◽  
Teresa Requena ◽  
Jose Antonio Lopez-Escamez
Keyword(s):  
Systematic Review ◽  
Candidate Genes ◽  
Rare Variants ◽  
De Novo ◽  
Complex Diseases ◽  
Genetic Studies ◽  
Complex Disorders ◽  
Extreme Phenotype ◽  
Disease Spectrum ◽  
Age Related

Exome sequencing has been commonly used to characterize rare diseases by selecting multiplex families or singletons with an extreme phenotype (EP) and searching for rare variants in coding regions. The EP strategy covers both extreme ends of a disease spectrum and it has been also used to investigate the contribution of rare variants to the heritability of complex clinical traits. We conducted a systematic review to find evidence supporting the use of EP strategies in the search for rare variants in genetic studies of complex diseases and highlight the contribution of rare variations to the genetic structure of polygenic conditions. After assessing the quality of the retrieved records, we selected 19 genetic studies considering EPs to demonstrate genetic association. All studies successfully identified several rare or de novo variants, and many novel candidate genes were also identified by selecting an EP. There is enough evidence to support that the EP approach for patients with an early onset of a disease can contribute to the identification of rare variants in candidate genes or pathways involved in complex diseases. EP patients may contribute to a better understanding of the underlying genetic architecture of common heterogeneous disorders such as tinnitus or age-related hearing loss.

Novel IRF6 Mutations Detected in Orofacial Cleft Patients by Targeted Massively Parallel Sequencing

2016 ◽  
Vol 96 (2) ◽  
pp. 179-185 ◽  
Author(s):  
K.D. Khandelwal ◽  
N. Ishorst ◽  
H. Zhou ◽  
K.U. Ludwig ◽  
H. Venselaar ◽  
...  
Keyword(s):  
Cleft Lip ◽  
Rare Variants ◽  
De Novo ◽  
Massively Parallel Sequencing ◽  
De Novo Mutation ◽  
De Novo Mutations ◽  
Orofacial Clefting ◽  
Unaffected Parent ◽  
Molecular Inversion Probes ◽  
Multiplex Sequencing

Common variants in interferon regulatory factor 6 ( IRF6) have been associated with nonsyndromic cleft lip with or without cleft palate (NSCL/P) as well as with tooth agenesis (TA). These variants contribute a small risk towards the 2 congenital conditions and explain only a small percentage of heritability. On the other hand, many IRF6 mutations are known to be a monogenic cause of disease for syndromic orofacial clefting (OFC). We hypothesize that IRF6 mutations in some rare instances could also cause nonsyndromic OFC. To find novel rare variants in IRF6 responsible for nonsyndromic OFC and TA, we performed targeted multiplex sequencing using molecular inversion probes (MIPs) in 1,072 OFC patients, 67 TA patients, and 706 controls. We identified 3 potentially pathogenic de novo mutations in OFC patients. In addition, 3 rare missense variants were identified, for which pathogenicity could not unequivocally be shown, as all variants were either inherited from an unaffected parent or the parental DNA was not available. Retrospective investigation of the patients with these variants revealed the presence of lip pits in one of the patients with a de novo mutation suggesting a Van der Woude syndrome (VWS) phenotype, whereas, in other patients, no lip pits were identified.

scholarly journals Multiple Genetic Rare Variants in Autism Spectrum Disorders: A Single-Center Targeted NGS Study

2021 ◽  
Vol 11 (17) ◽  
pp. 8096
Author(s):  
Chiara Reale ◽  
Valeria Tessarollo ◽  
Sara Bulgheroni ◽  
Silvia Annunziata ◽  
Andrea Legati ◽  
...  
Keyword(s):  
Rare Variants ◽  
De Novo ◽  
Autism Spectrum ◽  
Clinical Population ◽  
Chromosomal Microarray ◽  
Risk Alleles ◽  
Mutational Frequency ◽  
Targeted Ngs ◽  
Gene Panels ◽  
Next Generation Sequencing Ngs

Many studies based on chromosomal microarray and next-generation sequencing (NGS) have identified hundreds of genes associated with autism spectrum disorder (ASD) risk, demonstrating that there are several complex genetic factors that contribute to ASD risk. We performed targeted NGS gene panels for 120 selected genes, in a clinical population of 40 children with well-characterized ASD. The variants identified were annotated and filtered, focusing on rare variants with a minimum allele frequency <1% in GnomAD. We found 147 variants in 39 of the 40 patients. It was possible to perform family segregation analysis in 28 of the 40 patients. We found 4 de novo and 101 inherited variants. For the inherited variants, we observed that all the variants identified in the patients came equally from the paternal and maternal genetic makeup. We identified 9 genes that are more frequently mutated than the others, and upon comparing the mutational frequency of these 9 genes in our cohort and the mutational frequency in the GnomAD population, we found significantly increased frequencies of rare variants in our study population. This study supports the hypothesis that ASD is the result of a combination of rare deleterious variants (low contribution) and many low-risk alleles (genetic background), highlighting the importance of MET and SLIT3 and the potentially stronger involvement of FAT1 and VPS13B in ASD. Taken together, our findings reinforce the importance of using gene panels to understand the contribution of the different genes already associated with ASD in the pathogenesis of the disease.

scholarly journals Rare and de novo variants in 827 congenital diaphragmatic hernia probands implicate LONP1 and ALYREF as new candidate risk genes

2021 ◽  
Author(s):  
Lu Qiao ◽  
Le Xu ◽  
Lan Yu ◽  
Julia Wynn ◽  
Rebecca Hernan ◽  
...  
Keyword(s):  
Congenital Diaphragmatic Hernia ◽  
Diaphragmatic Hernia ◽  
Rare Variants ◽  
De Novo ◽  
Disease Genes ◽  
Risk Genes ◽  
Association Analyses ◽  
Significant Enrichment ◽  
Coding Variants

Congenital diaphragmatic hernia (CDH) is a severe congenital anomaly that is often accompanied by other anomalies. Although the role of genetics in the pathogenesis of CDH has been established, only a small number of disease genes have been identified. To further investigate the genetics of CDH, we analyzed de novo coding variants in 827 proband-parent trios and confirmed an overall significant enrichment of damaging de novo variants, especially in constrained genes. We identified LONP1 (Lon Peptidase 1, Mitochondrial) and ALYREF (Aly/REF Export Factor) as novel candidate CDH genes based on de novo variants at a false discovery rate below 0.05. We also performed ultra-rare variant association analyses in 748 cases and 11,220 ancestry-matched population controls and identified LONP1 as a risk gene contributing to CDH through both de novo and ultra-rare inherited largely heterozygous variants clustered in the core of the domains and segregating with CDH in familial cases. Approximately 3% of our CDH cohort was heterozygous with ultra-rare predicted damaging variants in LONP1 who have a range of clinical phenotypes including other anomalies in some individuals and higher mortality and requirement for extracorporeal membrane oxygenation. Mice with lung epithelium specific deletion of Lonp1 die immediately after birth and have reduced lung growth and branching that may at least partially explain the high mortality in humans. Our findings of both de novo and inherited rare variants in the same gene may have implications in the design and analysis for other genetic studies of congenital anomalies.

scholarly journals Genes and pathways implicated in tetralogy of Fallot revealed by ultra-rare variant burden analysis in 231 genome sequences

2020 ◽  
Author(s):  
Roozbeh Manshaei ◽  
Daniele Merico ◽  
Miriam S. Reuter ◽  
Worrawat Engchuan ◽  
Bahareh A. Mojarad ◽  
...  
Keyword(s):  
Tetralogy Of Fallot ◽  
Disulfide Bonds ◽  
Rare Variants ◽  
De Novo ◽  
Sequencing Data ◽  
Gene Set ◽  
Gene Sets ◽  
Statistical Support ◽  
Significant Burden ◽  
Burden Test

AbstractRecent genome-wide studies of rare genetic variants have begun to implicate novel mechanisms for tetralogy of Fallot (TOF), a severe congenital heart defect (CHD).To provide statistical support for case-only data without parental genomes, we re-analyzed genome sequences of 231 individuals with TOF or related CHD. We adapted a burden test originally developed for de novo variants to assess singleton variant burden in individual genes, and in gene-sets corresponding to functional pathways and mouse phenotypes, accounting for highly correlated gene-sets, and for multiple testing.The gene burden test identified a significant burden of deleterious missense variants in NOTCH1 (Bonferroni-corrected p-value <0.01). These NOTCH1 variants showed significant enrichment for those affecting the extracellular domain, and especially for disruption of cysteine residues forming disulfide bonds (OR 39.8 vs gnomAD). Individuals with NOTCH1 variants, all with TOF, were enriched for positive family history of CHD. Other genes not previously implicated in TOF had more modest statistical support and singleton missense variant results were non-significant for gene-set burden. For singleton truncating variants, the gene burden test confirmed significant burden in FLT4. Gene-set burden tests identified a cluster of pathways corresponding to VEGF signaling (FDR=0%), and of mouse phenotypes corresponding to abnormal vasculature (FDR=0.8%), that suggested additional candidate genes not previously identified (e.g., WNT5A and ZFAND5). Analyses using unrelated sequencing datasets supported specificity of the findings for CHD.The findings support the importance of ultra-rare variants disrupting genes involved in VEGF and NOTCH signaling in the genetic architecture of TOF. These proof-of-principle data indicate that this statistical methodology could assist in analyzing case-only sequencing data in which ultra-rare variants, whether de novo or inherited, contribute to the genetic etiopathogenesis of a complex disorder.Author summaryWe analyzed the ultra-rare nonsynonymous variant burden for genome sequencing data from 231 individuals with congenital heart defects, most with tetralogy of Fallot. We adapted a burden test originally developed for de novo variants. In line with other studies, we identified a significant truncating variant burden for FLT4 and deleterious missense burden for NOTCH1, both passing a stringent Bonferroni multiple-test correction. For NOTCH1, we observed frequent disruption of cysteine residues establishing disulfide bonds in the extracellular domain. We also identified genes with BH-FDR <10% that were not previously implicated. To overcome limited power for individual genes, we tested gene-sets corresponding to functional pathways and mouse phenotypes. Gene-set burden of truncating variants was significant for vascular endothelial growth factor signaling and abnormal vasculature phenotypes. These results confirmed previous findings and suggested additional candidate genes for experimental validation in future studies. This methodology can be extended to other case-only sequencing data in which ultra-rare variants make a substantial contribution to genetic etiology.

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