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Rodrigues Alves Barbosa V, Maroilley T, Diao C, Colvin-James L, Perrier R, Tarailo-Graovac M. Single variant, yet "double trouble": TSC and KBG syndrome because of a large de novo inversion. Life Sci Alliance 2024; 7:e202302115. [PMID: 38253421 PMCID: PMC10803213 DOI: 10.26508/lsa.202302115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 01/12/2024] [Accepted: 01/16/2024] [Indexed: 01/24/2024] Open
Abstract
Despite the advances in high-throughput sequencing, many rare disease patients remain undiagnosed. In particular, the patients with well-defined clinical phenotypes and established clinical diagnosis, yet missing or partial genetic diagnosis, may hold a clue to more complex genetic mechanisms of a disease that could be missed by available clinical tests. Here, we report a patient with a clinical diagnosis of Tuberous sclerosis, combined with unusual secondary features, but negative clinical tests including TSC1 and TSC2 Short-read whole-genome sequencing combined with advanced bioinformatics analyses were successful in uncovering a de novo pericentric 87-Mb inversion with breakpoints in TSC2 and ANKRD11, which explains the TSC clinical diagnosis, and confirms a second underlying monogenic disorder, KBG syndrome. Our findings illustrate how complex variants, such as large inversions, may be missed by clinical tests and further highlight the importance of well-defined clinical diagnoses in uncovering complex molecular mechanisms of a disease, such as complex variants and "double trouble" effects.
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Affiliation(s)
- Victoria Rodrigues Alves Barbosa
- https://ror.org/03yjb2x39 Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, Canada
- https://ror.org/03yjb2x39 Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, Canada
- https://ror.org/03yjb2x39 Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Canada
| | - Tatiana Maroilley
- https://ror.org/03yjb2x39 Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, Canada
- https://ror.org/03yjb2x39 Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, Canada
- https://ror.org/03yjb2x39 Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Canada
| | - Catherine Diao
- https://ror.org/03yjb2x39 Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, Canada
- https://ror.org/03yjb2x39 Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, Canada
- https://ror.org/03yjb2x39 Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Canada
| | - Leslie Colvin-James
- https://ror.org/03yjb2x39 Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, Canada
- https://ror.org/03yjb2x39 Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Canada
| | - Renee Perrier
- https://ror.org/03yjb2x39 Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, Canada
- https://ror.org/03yjb2x39 Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Canada
| | - Maja Tarailo-Graovac
- https://ror.org/03yjb2x39 Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, Canada
- https://ror.org/03yjb2x39 Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, Canada
- https://ror.org/03yjb2x39 Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Canada
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2
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Regier DA, Loewen R, Chan B, Ehman M, Pollard S, Friedman JM, Stockler-Ipsiroglu S, van Karnebeek C, Race S, Elliott AM, Dragojlovic N, Lynd LD, Weymann D. Real-world diagnostic outcomes and cost-effectiveness of genome-wide sequencing for developmental and seizure disorders: Evidence from Canada. Genet Med 2024; 26:101069. [PMID: 38205742 DOI: 10.1016/j.gim.2024.101069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 01/03/2024] [Accepted: 01/04/2024] [Indexed: 01/12/2024] Open
Abstract
PURPOSE To determine real-world diagnostic rates, cost trajectories, and cost-effectiveness of exome sequencing (ES) and genome sequencing (GS) for children with developmental and/or seizure disorders in British Columbia, Canada. METHODS Based on medical records review, we estimated real-world costs and outcomes for 491 patients who underwent standard of care (SOC) diagnostic testing at British Columbia Children's Hospital. Results informed a state-transition Markov model examining cost-effectiveness of 3 competing diagnostic strategies: (1) SOC with last-tier access to ES, (2) streamlined ES access, and (3) first-tier GS. RESULTS Through SOC, 49.4% (95% CI: 40.6, 58.2) of patients were diagnosed at an average cost of C$11,683 per patient (95% CI: 9200, 14,166). Compared with SOC, earlier ES or GS access yielded similar or improved diagnostic rates and shorter times to genetic diagnosis, with 94% of simulations demonstrating cost savings for streamlined ES and 60% for first-tier GS. Net benefit from the perspective of the health care system was C$2956 (95% CI: -608, 6519) for streamlined ES compared with SOC. CONCLUSION Using real-world data, we found earlier access to ES may yield more rapid genetic diagnosis of childhood developmental and seizure disorders and cost savings compared with current practice in a Canadian health care system.
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Affiliation(s)
- Dean A Regier
- School of Population and Public Health, Faculty of Medicine, University of British Columbia, Vancouver, Canada; Cancer Control Research, BC Cancer Research Institute, Vancouver, Canada
| | - Rosalie Loewen
- Cancer Control Research, BC Cancer Research Institute, Vancouver, Canada
| | - Brandon Chan
- Cancer Control Research, BC Cancer Research Institute, Vancouver, Canada
| | - Morgan Ehman
- Cancer Control Research, BC Cancer Research Institute, Vancouver, Canada
| | - Samantha Pollard
- Cancer Control Research, BC Cancer Research Institute, Vancouver, Canada
| | - Jan M Friedman
- Department of Medical Genetics, University of British Columbia, Vancouver, Canada; BC Children's Hospital Research Institute, Vancouver, Canada
| | - Sylvia Stockler-Ipsiroglu
- BC Children's Hospital Research Institute, Vancouver, Canada; Department of Pediatrics, Faculty of Medicine, University of British Columbia, Vancouver, Canada; Division of Biochemical Genetics, BC Children's Hospital, Vancouver, Canada
| | - Clara van Karnebeek
- Department of Pediatrics, Faculty of Medicine, University of British Columbia, Vancouver, Canada; Departments of Pediatrics and Human Genetics, Emma Center for Personalized Medicine, Amsterdam University Medical Centers, Amsterdam, The Netherlands
| | - Simone Race
- Division of Biochemical Genetics, BC Children's Hospital, Vancouver, Canada
| | - Alison M Elliott
- Department of Medical Genetics, University of British Columbia, Vancouver, Canada; BC Children's Hospital Research Institute, Vancouver, Canada
| | - Nick Dragojlovic
- Collaboration for Outcomes Research and Evaluation, Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, Canada
| | - Larry D Lynd
- Collaboration for Outcomes Research and Evaluation, Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, Canada; Centre for Health Evaluation and Outcomes Sciences, Providence Health Research Institute, Vancouver, Canada
| | - Deirdre Weymann
- Cancer Control Research, BC Cancer Research Institute, Vancouver, Canada.
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3
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Cotra F, Maroilley T, Tarailo-Graovac M. Molecular basis of essential and morphological variations across 12 balancer strains in C. elegans. MICROPUBLICATION BIOLOGY 2023; 2023:10.17912/micropub.biology.000846. [PMID: 37313226 PMCID: PMC10259336 DOI: 10.17912/micropub.biology.000846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 05/05/2023] [Accepted: 05/23/2023] [Indexed: 06/15/2023]
Abstract
Balancers are primarily chromosomal rearrangements that allow lethal or sterile mutations to be stably maintained as heterozygotes. Strains with balanced lethal/sterile mutations are available at the Caenorhabditis Genetics Center. Such strains harbor morphological markers, with associated molecular changes, that are in trans to the balancer. In many cases, only the genetic position (in cM) has been described for balanced mutations or morphological markers. We used short-read whole genome sequencing to uncover the genomic position of those variants (balanced mutations and linked markers) and predicted their effect. We investigated 12 different strains, and characterized at a molecular level 12 variants.
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Affiliation(s)
- Filip Cotra
- Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta, Canada
| | - Tatiana Maroilley
- Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta, Canada
| | - Maja Tarailo-Graovac
- Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta, Canada
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4
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Maroilley T, Tsai MH, Mascarenhas R, Diao C, Khanbabaei M, Kaya S, Depienne C, Tarailo-Graovac M, Klein KM. A novel FAME1 repeat configuration in a European family identified using a combined genomics approach. Epilepsia Open 2023. [PMID: 36740228 DOI: 10.1002/epi4.12702] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 01/28/2023] [Indexed: 02/07/2023] Open
Abstract
Familial adult myoclonic epilepsy (FAME) is an adult-onset neurological disease characterized by cortical tremor, myoclonus, and seizures due to a pentanucleotide repeat expansion: a combination of pathogenic TTTCA expansion associated with a TTTTA repeat in introns of six different genes. Repeat-primed PCR (RP-PCR) is an inexpensive test for expansions at known loci. The analysis of the SAMD12 locus revealed that the repeats have different size, configuration, and composition. The TTTCA repeats can be very long (>1000 repeats) but also very short (14 being the shortest identified). Here, we report siblings of European descent with the clinical diagnosis of FAME yet a negative RP-PCR test. Using short-read genome sequencing, we identified the pentanucleotide expansion in intron 4 of SAMD12, which was confirmed by CRIPSR-Cas9-mediated enrichment and long-read sequencing to be of (TTTTA)~879 (TTTCA)3 (TTTTA)7 (TTTCA)7 configuration. Our finding is the first to associate the SAMD12 locus in European patients with FAME and currently represents the shortest identified TTTCA expansion. Our results suggest that the SAMD12 locus should be tested in patients with suspected FAME independent of ethnicity. Furthermore, RP-PCR may miss the underlying mutation, and genome sequencing may be needed to confirm the pathogenic repeat.
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Affiliation(s)
- Tatiana Maroilley
- Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada
| | - Meng-Han Tsai
- Department of Neurology and Medical Research, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan.,School of Medicine, College of Medicine, Taoyuan, Chang Gung University, Taoyuan City, Taiwan
| | - Rumika Mascarenhas
- Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada.,Department of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Catherine Diao
- Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada
| | - Maryam Khanbabaei
- Department of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada
| | - Sabine Kaya
- Institute of Human Genetics, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Christel Depienne
- Institute of Human Genetics, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Maja Tarailo-Graovac
- Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada
| | - Karl Martin Klein
- Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada.,Department of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada.,Department of Community Health Sciences, University of Calgary, Calgary, Alberta, Canada.,Epilepsy Center Frankfurt Rhine-Main, Department of Neurology, Center of Neurology and Neurosurgery, University Hospital, Center for Personalized Translational Epilepsy Research (CePTER), Goethe-University Frankfurt, Frankfurt, Germany
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5
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The Power of Clinical Diagnosis for Deciphering Complex Genetic Mechanisms in Rare Diseases. Genes (Basel) 2023; 14:genes14010196. [PMID: 36672937 PMCID: PMC9858967 DOI: 10.3390/genes14010196] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 01/05/2023] [Accepted: 01/09/2023] [Indexed: 01/13/2023] Open
Abstract
Complex genetic disease mechanisms, such as structural or non-coding variants, currently pose a substantial difficulty in frontline diagnostic tests. They thus may account for most unsolved rare disease patients regardless of the clinical phenotype. However, the clinical diagnosis can narrow the genetic focus to just a couple of genes for patients with well-established syndromes defined by prominent physical and/or unique biochemical phenotypes, allowing deeper analyses to consider complex genetic origin. Then, clinical-diagnosis-driven genome sequencing strategies may expedite the development of testing and analytical methods to account for complex disease mechanisms as well as to advance functional assays for the confirmation of complex variants, clinical management, and the development of new therapies.
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6
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Maroilley T, Flibotte S, Jean F, Rodrigues Alves Barbosa V, Galbraith A, Chida AR, Cotra F, Li X, Oncea L, Edgley M, Moerman D, Tarailo-Graovac M. Genome sequencing of C. elegans balancer strains reveals previously unappreciated complex genomic rearrangements. Genome Res 2023; 33:154-167. [PMID: 36617680 PMCID: PMC9977149 DOI: 10.1101/gr.276988.122] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 11/29/2022] [Indexed: 12/12/2022]
Abstract
Genetic balancers in Caenorhabditis elegans are complex variants that allow lethal or sterile mutations to be stably maintained in a heterozygous state by suppressing crossover events. Balancers constitute an invaluable tool in the C. elegans scientific community and have been widely used for decades. The first/traditional balancers were created by applying X-rays, UV, or gamma radiation on C. elegans strains, generating random genomic rearrangements. Their structures have been mostly explored with low-resolution genetic techniques (e.g., fluorescence in situ hybridization or PCR), before genomic mapping and molecular characterization through sequencing became feasible. As a result, the precise nature of most chromosomal rearrangements remains unknown, whereas, more recently, balancers have been engineered using the CRISPR-Cas9 technique for which the structure of the chromosomal rearrangement has been predesigned. Using short-read whole-genome sequencing (srWGS) and tailored bioinformatic analyses, we previously interpreted the structure of four chromosomal balancers randomly created by mutagenesis processes. Here, we have extended our analyses to five CRISPR-Cas9 balancers and 17 additional traditional balancing rearrangements. We detected and experimentally validated their breakpoints and have interpreted the balancer structures. Many of the balancers were found to be more intricate than previously described, being composed of complex genomic rearrangements (CGRs) such as chromoanagenesis-like events. Furthermore, srWGS revealed additional structural variants and CGRs not known to be part of the balancer genomes. Altogether, our study provides a comprehensive resource of complex genomic variations in C. elegans and highlights the power of srWGS to study the complexity of genomes by applying tailored analyses.
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Affiliation(s)
- Tatiana Maroilley
- Departments of Biochemistry, Molecular Biology and Medical Genetics, Cumming School of Medicine, University of Calgary, Alberta T2N 4N1, Canada;,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Stephane Flibotte
- UBC/LSI Bioinformatics Facility, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Francesca Jean
- Departments of Biochemistry, Molecular Biology and Medical Genetics, Cumming School of Medicine, University of Calgary, Alberta T2N 4N1, Canada;,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Victoria Rodrigues Alves Barbosa
- Departments of Biochemistry, Molecular Biology and Medical Genetics, Cumming School of Medicine, University of Calgary, Alberta T2N 4N1, Canada;,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Andrew Galbraith
- Departments of Biochemistry, Molecular Biology and Medical Genetics, Cumming School of Medicine, University of Calgary, Alberta T2N 4N1, Canada;,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Afiya Razia Chida
- Departments of Biochemistry, Molecular Biology and Medical Genetics, Cumming School of Medicine, University of Calgary, Alberta T2N 4N1, Canada;,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Filip Cotra
- Departments of Biochemistry, Molecular Biology and Medical Genetics, Cumming School of Medicine, University of Calgary, Alberta T2N 4N1, Canada;,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Xiao Li
- Departments of Biochemistry, Molecular Biology and Medical Genetics, Cumming School of Medicine, University of Calgary, Alberta T2N 4N1, Canada;,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Larisa Oncea
- Departments of Biochemistry, Molecular Biology and Medical Genetics, Cumming School of Medicine, University of Calgary, Alberta T2N 4N1, Canada;,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Mark Edgley
- Department of Zoology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Don Moerman
- Department of Zoology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Maja Tarailo-Graovac
- Departments of Biochemistry, Molecular Biology and Medical Genetics, Cumming School of Medicine, University of Calgary, Alberta T2N 4N1, Canada;,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta T2N 4N1, Canada
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7
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Lesack K, Mariene GM, Andersen EC, Wasmuth JD. Different structural variant prediction tools yield considerably different results in Caenorhabditis elegans. PLoS One 2022; 17:e0278424. [PMID: 36584177 PMCID: PMC9803319 DOI: 10.1371/journal.pone.0278424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 11/15/2022] [Indexed: 01/01/2023] Open
Abstract
The accurate characterization of structural variation is crucial for our understanding of how large chromosomal alterations affect phenotypic differences and contribute to genome evolution. Whole-genome sequencing is a popular approach for identifying structural variants, but the accuracy of popular tools remains unclear due to the limitations of existing benchmarks. Moreover, the performance of these tools for predicting variants in non-human genomes is less certain, as most tools were developed and benchmarked using data from the human genome. To evaluate the use of long-read data for the validation of short-read structural variant calls, the agreement between predictions from a short-read ensemble learning method and long-read tools were compared using real and simulated data from Caenorhabditis elegans. The results obtained from simulated data indicate that the best performing tool is contingent on the type and size of the variant, as well as the sequencing depth of coverage. These results also highlight the need for reference datasets generated from real data that can be used as 'ground truth' in benchmarks.
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Affiliation(s)
- Kyle Lesack
- Faculty of Veterinary Medicine, University of Calgary, Alberta, Canada
- Host-Parasite Interactions Research Training Network, University of Calgary, Alberta, Canada
| | - Grace M. Mariene
- Faculty of Veterinary Medicine, University of Calgary, Alberta, Canada
- Host-Parasite Interactions Research Training Network, University of Calgary, Alberta, Canada
| | - Erik C. Andersen
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, United States of America
| | - James D. Wasmuth
- Faculty of Veterinary Medicine, University of Calgary, Alberta, Canada
- Host-Parasite Interactions Research Training Network, University of Calgary, Alberta, Canada
- * E-mail:
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8
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Epidemiology of Δ8THC-Related Carcinogenesis in USA: A Panel Regression and Causal Inferential Study. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19137726. [PMID: 35805384 PMCID: PMC9265369 DOI: 10.3390/ijerph19137726] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 06/18/2022] [Accepted: 06/21/2022] [Indexed: 12/26/2022]
Abstract
The use of Δ8THC is increasing at present across the USA in association with widespread cannabis legalization and the common notion that it is “legal weed”. As genotoxic actions have been described for many cannabinoids, we studied the cancer epidemiology of Δ8THC. Data on 34 cancer types was from the Centers for Disease Control Atlanta Georgia, substance abuse data from the Substance Abuse and Mental Health Services Administration, ethnicity and income data from the U.S. Census Bureau, and cannabinoid concentration data from the Drug Enforcement Agency, were combined and processed in R. Eight cancers (corpus uteri, liver, gastric cardia, breast and post-menopausal breast, anorectum, pancreas, and thyroid) were related to Δ8THC exposure on bivariate testing, and 18 (additionally, stomach, Hodgkins, and Non-Hodgkins lymphomas, ovary, cervix uteri, gall bladder, oropharynx, bladder, lung, esophagus, colorectal cancer, and all cancers (excluding non-melanoma skin cancer)) demonstrated positive average marginal effects on fully adjusted inverse probability weighted interactive panel regression. Many minimum E-Values (mEVs) were infinite. p-values rose from 8.04 × 10−78. Marginal effect calculations revealed that 18 Δ8THC-related cancers are predicted to lead to a further 8.58 cases/100,000 compared to 7.93 for alcoholism and −8.48 for tobacco. Results indicate that between 8 and 20/34 cancer types were associated with Δ8THC exposure, with very high effect sizes (mEVs) and marginal effects after adjustment exceeding tobacco and alcohol, fulfilling the epidemiological criteria of causality and suggesting a cannabinoid class effect. The inclusion of pediatric leukemias and testicular cancer herein demonstrates heritable malignant teratogenesis.
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9
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Maroilley T, Wright NAM, Diao C, MacLaren L, Pfeffer G, Sarna JR, Billie Au PY, Tarailo-Graovac M. Case Report: Biallelic Loss of Function ATM due to Pathogenic Synonymous and Novel Deep Intronic Variant c.1803-270T > G Identified by Genome Sequencing in a Child With Ataxia–Telangiectasia. Front Genet 2022; 13:815210. [PMID: 35145552 PMCID: PMC8822238 DOI: 10.3389/fgene.2022.815210] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 01/03/2022] [Indexed: 11/26/2022] Open
Abstract
Ataxia–telangiectasia (AT) is a complex neurodegenerative disease with an increased risk for bone marrow failure and malignancy. AT is caused by biallelic loss of function variants in ATM, which encodes a phosphatidylinositol 3-kinase that responds to DNA damage. Herein, we report a child with progressive ataxia, chorea, and genome instability, highly suggestive of AT. The clinical ataxia gene panel identified a maternal heterozygous synonymous variant (NM_000051.3: c.2250G > A), previously described to result in exon 14 skipping. Subsequently, trio genome sequencing led to the identification of a novel deep intronic variant [NG_009830.1(NM_000051.3): c.1803-270T > G] inherited from the father. Transcript analyses revealed that c.1803-270T > G results in aberrant inclusion of 56 base pairs of intron 11. In silico tests predicted a premature stop codon as a consequence, suggesting non-functional ATM; and DNA repair analyses confirmed functional loss of ATM. Our findings highlight the power of genome sequencing, considering deep intronic variants in undiagnosed rare disease patients.
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Affiliation(s)
- Tatiana Maroilley
- Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, AB, Canada
| | - Nicola A. M. Wright
- Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, AB, Canada
- Section of Pediatric Hematology-Immunology, Department of Pediatrics, Alberta Children’s Hospital, University of Calgary, Calgary, AB, Canada
| | - Catherine Diao
- Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, AB, Canada
| | - Linda MacLaren
- Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, AB, Canada
| | - Gerald Pfeffer
- Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Department of Clinical Neurosciences and Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Justyna R. Sarna
- Department of Clinical Neurosciences and Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Ping Yee Billie Au
- Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, AB, Canada
- *Correspondence: Ping Yee Billie Au, ; Maja Tarailo-Graovac,
| | - Maja Tarailo-Graovac
- Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, AB, Canada
- *Correspondence: Ping Yee Billie Au, ; Maja Tarailo-Graovac,
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10
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Jean F, Stasiuk S, Maroilley T, Diao C, Galbraith A, Tarailo-Graovac M. Whole genome sequencing facilitates intragenic variant interpretation following modifier screening in C. elegans. BMC Genomics 2021; 22:820. [PMID: 34773966 PMCID: PMC8590768 DOI: 10.1186/s12864-021-08142-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 11/01/2021] [Indexed: 11/10/2022] Open
Abstract
Background Intragenic modifiers (in-phase, second-site variants) are known to have dramatic effects on clinical outcomes, affecting disease attributes such as severity or age of onset. However, despite their clinical importance, the focus of many genetic screens in model systems is on the discovery of extragenic variants, with many labs still relying upon more traditional methods to identify modifiers. However, traditional methods such as PCR and Sanger sequencing can be time-intensive and do not permit a thorough understanding of the intragenic modifier effects in the context of non-isogenic genomic backgrounds. Results Here, we apply high throughput approaches to identify and understand intragenic modifiers using Caenorhabditis elegans. Specifically, we applied whole genome sequencing (WGS) to a mutagen-induced forward genetic screen to identify intragenic suppressors of a temperature-sensitive zyg-1(it25) allele in C. elegans. ZYG-1 is a polo kinase that is important for centriole function and cell divisions, and mutations that truncate its human orthologue, PLK4, have been associated with microcephaly. Combining WGS and CRISPR/Cas9, we rapidly identify intragenic modifiers, show that these variants are distributed non-randomly throughout zyg-1 and that genomic context plays an important role on phenotypic outcomes. Conclusions Ultimately, our work shows that WGS facilitates high-throughput identification of intragenic modifiers in clinically relevant genes by reducing hands-on research time and overall costs and by allowing thorough understanding of the intragenic phenotypic effects in the context of different genetic backgrounds. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-021-08142-8.
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Affiliation(s)
- Francesca Jean
- Departments of Biochemistry, Molecular Biology and Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada
| | - Susan Stasiuk
- Departments of Biochemistry, Molecular Biology and Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada
| | - Tatiana Maroilley
- Departments of Biochemistry, Molecular Biology and Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada
| | - Catherine Diao
- Departments of Biochemistry, Molecular Biology and Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada
| | - Andrew Galbraith
- Departments of Biochemistry, Molecular Biology and Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada
| | - Maja Tarailo-Graovac
- Departments of Biochemistry, Molecular Biology and Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada. .,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada.
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