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Pereira SSS, Pinto IP, Santos VCDP, Silva RC, Costa EOA, da Cruz AS, da Cruz AD, da Silva CC, Minasi LB. Analysis of parental origin of de novo pathogenic CNVs in patients with intellectual disability. Genet Mol Biol 2024; 47:e20230313. [PMID: 39136576 PMCID: PMC11320663 DOI: 10.1590/1678-4685-gmb-2023-0313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Accepted: 06/25/2024] [Indexed: 08/16/2024] Open
Abstract
Chromosomal Microarray Analysis (CMA) has increased the comprehension of the mechanisms of copy number variation (CNV) formation, classification of these rearrangements, type of recurrence, and its origin, and has also been a powerful approach to identifying CNVs in individuals with intellectual disability. The aim of this study was to establish the parental origin of de novo pathogenic CNV in a cohort of patients with intellectual disability from the public health system of Goiás-Brazil. CMA was done in 76 trios and we identified 15 de novo pathogenic CNVs in 12 patients with intellectual disability. In a total of 15 de novo pathogenic CNV, 60% were derived from the maternal germline and 40% from the paternal germline. CNV flanked by low copy repeats (LCR) were identified in 46.7% and most of them were of maternal origin. No significant association was observed between paternal age and the mutation rate of de novo CNVs. The presence of high-identity LCRs increases the occurrence of CNV formation mediated by non-allelic homologous recombination and the majority of paternal CNVs are non-recurrent. The mechanism of formation of these CNV may have been by microhomology-mediated break-induced replication or non-homologous end joining.
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Affiliation(s)
- Samara Socorro Silva Pereira
- Pontifícia Universidade Católica de Goiás, Escola de Ciências Médicas e da Vida, Programa de Pós-Graduação em Genética, Núcleo de Pesquisa Replicon, Goiânia, GO, Brazil
- Universidade Federal de Goiás, Programa de Pós-Graduação em Genética e Biologia Molecular, Goiânia, GO, Brazil
| | - Irene Plaza Pinto
- Pontifícia Universidade Católica de Goiás, Escola de Ciências Médicas e da Vida, Programa de Pós-Graduação em Genética, Núcleo de Pesquisa Replicon, Goiânia, GO, Brazil
| | - Victor Cortázio do Prado Santos
- Pontifícia Universidade Católica de Goiás, Escola de Ciências Médicas e da Vida, Programa de Pós-Graduação em Genética, Núcleo de Pesquisa Replicon, Goiânia, GO, Brazil
- Universidade Federal de Goiás, Programa de Pós-Graduação em Genética e Biologia Molecular, Goiânia, GO, Brazil
| | - Rafael Carneiro Silva
- Pontifícia Universidade Católica de Goiás, Escola de Ciências Médicas e da Vida, Programa de Pós-Graduação em Genética, Núcleo de Pesquisa Replicon, Goiânia, GO, Brazil
| | - Emília Oliveira Alves Costa
- Pontifícia Universidade Católica de Goiás, Escola de Ciências Médicas e da Vida, Programa de Pós-Graduação em Genética, Núcleo de Pesquisa Replicon, Goiânia, GO, Brazil
| | - Alex Silva da Cruz
- Pontifícia Universidade Católica de Goiás, Escola de Ciências Médicas e da Vida, Programa de Pós-Graduação em Genética, Núcleo de Pesquisa Replicon, Goiânia, GO, Brazil
| | - Aparecido Divino da Cruz
- Pontifícia Universidade Católica de Goiás, Escola de Ciências Médicas e da Vida, Programa de Pós-Graduação em Genética, Núcleo de Pesquisa Replicon, Goiânia, GO, Brazil
- Secretaria Estadual de Saúde de Goiás, Centro Estadual de Reabilitação e Readaptação Dr. Henrique Santillo, Goiânia, GO, Brazil
- Universidade Federal de Goiás, Programa de Pós-Graduação em Genética e Biologia Molecular, Goiânia, GO, Brazil
| | - Cláudio Carlos da Silva
- Pontifícia Universidade Católica de Goiás, Escola de Ciências Médicas e da Vida, Programa de Pós-Graduação em Genética, Núcleo de Pesquisa Replicon, Goiânia, GO, Brazil
- Secretaria Estadual de Saúde de Goiás, Centro Estadual de Reabilitação e Readaptação Dr. Henrique Santillo, Goiânia, GO, Brazil
| | - Lysa Bernardes Minasi
- Pontifícia Universidade Católica de Goiás, Escola de Ciências Médicas e da Vida, Programa de Pós-Graduação em Genética, Núcleo de Pesquisa Replicon, Goiânia, GO, Brazil
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Danecek P, Gardner EJ, Fitzgerald TW, Gallone G, Kaplanis J, Eberhardt RY, Wright CF, Firth HV, Hurles ME. Detection and characterization of copy-number variants from exome sequencing in the DDD study. GENETICS IN MEDICINE OPEN 2024; 2:101818. [PMID: 39669630 PMCID: PMC11613862 DOI: 10.1016/j.gimo.2024.101818] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 01/18/2024] [Accepted: 01/23/2024] [Indexed: 12/14/2024]
Abstract
Purpose Structural variants such as multiexon deletions and duplications are an important cause of disease but are often overlooked in standard exome/genome sequencing analysis. We aimed to evaluate the detection of copy-number variants (CNVs) from exome sequencing (ES) in comparison with genome-wide low-resolution and exon-resolution chromosomal microarrays (CMAs) and to characterize the properties of de novo CNVs in a large clinical cohort. Methods We performed CNV detection using ES of 9859 parent-offspring trios in the Deciphering Developmental Disorders (DDD) study and compared them with CNVs detected from exon-resolution array comparative genomic hybridization in 5197 probands from the DDD study. Results Integrating calls from multiple ES-based CNV algorithms using random forest machine learning generated a higher quality data set than using individual algorithms. Both ES- and array comparative genomic hybridization-based approaches had the same sensitivity of 89% and detected the same number of unique pathogenic CNVs not called by the other approach. Of DDD probands prescreened with low-resolution CMAs, 2.6% had a pathogenic CNV detected by higher-resolution assays. De novo CNVs were strongly enriched in known DD-associated genes and exhibited no bias in parental age or sex. Conclusion ES-based CNV calling has higher sensitivity than low-resolution CMAs currently in clinical use and comparable sensitivity to exon-resolution CMA. With sufficient investment in bioinformatic analysis, exome-based CNV detection could replace low-resolution CMA for detecting pathogenic CNVs.
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Affiliation(s)
- Petr Danecek
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, United Kingdom
| | - Eugene J. Gardner
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, United Kingdom
| | | | - Giuseppe Gallone
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, United Kingdom
| | - Joanna Kaplanis
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, United Kingdom
| | - Ruth Y. Eberhardt
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, United Kingdom
| | - Caroline F. Wright
- Department of Clinical and Biomedical Sciences, University of Exeter Medical School, Royal Devon and Exeter Hospital, Exeter, United Kingdom
| | - Helen V. Firth
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, United Kingdom
- Department of Clinical Genetics, Cambridge University Hospitals NHS Foundation Trust, Cambridge, United Kingdom
| | - Matthew E. Hurles
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, United Kingdom
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Cai M, Lv A, Zhao W, Xu L, Lin N, Huang H. Intrauterine ultrasound phenotyping, molecular characteristics, and postnatal follow-up of fetuses with the 15q11.2 BP1-BP2 microdeletion syndrome: a single-center, retrospective clinical study. BMC Pregnancy Childbirth 2024; 24:23. [PMID: 38172840 PMCID: PMC10763152 DOI: 10.1186/s12884-023-06223-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Accepted: 12/22/2023] [Indexed: 01/05/2024] Open
Abstract
OBJECTIVES The 15q11.2 BP1-BP2 microdeletion is associated with neurodevelopmental diseases. However, most studies on this microdeletion have focused on adults and children. Thus, in this study, we summarized the molecular characteristics of fetuses with the 15q11.2 BP1-BP2 microdeletion and their postnatal follow-up to guide prenatal diagnosis. METHODS Ten thousand fetuses were retrospectively subjected to karyotype analysis and chromosome microarray analysis. RESULTS Chromosome microarray analysis revealed that 37 (0.4%) of the 10,000 fetuses had 15q11.2 BP1-BP2 microdeletions. The fragment size of the 15q11.2 BP1-BP2 region was approximately 312-855 kb and encompassed TUBGCP5, CYFIP1, NIPA2, and NIPA1 genes. Twenty-five of the 37 fetuses with this microdeletion showed phenotypic abnormalities. The most common ultrasonic structural abnormality was congenital heart disease, followed by renal dysplasia and Dandy-Walker malformation. The 15q11.2 BP1-BP2 microdeletion was inherited from the father and mother in 6 and 10 cases, respectively, and de novo inherited in 4 cases. In the postnatal follow-up, 16.1% of the children had postnatal abnormalities. CONCLUSION Fetuses with the 15q11.2 BP1-BP2 microdeletion showed high proportions of phenotypic abnormalities, but the specificity of penetrance was low. Thus, fetuses with this syndrome are potentially at a higher risk of postnatal growth/behavioral problems and require continuous monitoring of growth and development.
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Affiliation(s)
- Meiying Cai
- Medical Genetic Diagnosis and Therapy Center, Fujian Maternity and Child Health Hospital College of Clinical Medicine for Obstetrics & Gynecology and Pediatrics, Fujian Medical University, Fujian Key Laboratory for Prenatal Diagnosis and Birth Defect, Fuzhou, China
| | - Aixiang Lv
- Medical Genetic Diagnosis and Therapy Center, Fujian Maternity and Child Health Hospital College of Clinical Medicine for Obstetrics & Gynecology and Pediatrics, Fujian Medical University, Fujian Key Laboratory for Prenatal Diagnosis and Birth Defect, Fuzhou, China
| | - Wantong Zhao
- Medical Genetic Diagnosis and Therapy Center, Fujian Maternity and Child Health Hospital College of Clinical Medicine for Obstetrics & Gynecology and Pediatrics, Fujian Medical University, Fujian Key Laboratory for Prenatal Diagnosis and Birth Defect, Fuzhou, China
| | - Liangpu Xu
- Medical Genetic Diagnosis and Therapy Center, Fujian Maternity and Child Health Hospital College of Clinical Medicine for Obstetrics & Gynecology and Pediatrics, Fujian Medical University, Fujian Key Laboratory for Prenatal Diagnosis and Birth Defect, Fuzhou, China.
| | - Na Lin
- Medical Genetic Diagnosis and Therapy Center, Fujian Maternity and Child Health Hospital College of Clinical Medicine for Obstetrics & Gynecology and Pediatrics, Fujian Medical University, Fujian Key Laboratory for Prenatal Diagnosis and Birth Defect, Fuzhou, China.
| | - Hailong Huang
- Medical Genetic Diagnosis and Therapy Center, Fujian Maternity and Child Health Hospital College of Clinical Medicine for Obstetrics & Gynecology and Pediatrics, Fujian Medical University, Fujian Key Laboratory for Prenatal Diagnosis and Birth Defect, Fuzhou, China.
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Zuffardi O, Fichera M, Bonaglia MC. The embryo battle against adverse genomes: Are de novo terminal deletions the rescue of unfavorable zygotic imbalances? Eur J Med Genet 2022; 65:104532. [PMID: 35724817 DOI: 10.1016/j.ejmg.2022.104532] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 04/02/2022] [Accepted: 05/21/2022] [Indexed: 11/03/2022]
Abstract
De novo distal deletions are structural variants considered to be already present in the zygote. However, investigations especially in the prenatal setting have documented that they are often in mosaic with cell lines in which the same deleted chromosome shows different types of aberrations such as: 1) neutral copy variants with loss of heterozygosity that replace the deleted region with equivalent portions of the homologous chromosome and create distal uniparental disomy (UPD); 2) derivative chromosomes where the deleted one ends with the distal region of another chromosome or has the shape of a ring; 3) U-type mirror dicentric or inv-dup del rearrangements. Unstable dicentrics had already been entailed as causative of terminal deletions even when no trace of the reciprocal inv-dup del had been detected. To clarify the mechanism of origin of distal deletions, we examined PubMed using as keywords: complex/mosaic chromosomal deletions, distal UPD, U-type dicentrics, inv-dup del chromosomes, excluding the recurrent inv-dup del(8p)s which are known to originate by NAHR at the maternal meiosis. The literature has shown that U-type dicentrics leading to nearly complete trisomy and therefore incompatible with zygotic survival underlie many types of de novo unbalanced rearrangements, including terminal deletions. In the early embryo, the position of the postzygotic breaks of the dicentric, the different ways of acquiring telomeres by the broken portions and the selection of the most favorable cell lines in the different tissues determine the prevalence of one or the other rearrangement. Multiple lines with simple terminal deletions, inv-dup dels, unbalanced translocations and segmental UPDs can coexist in various mosaic combinations although it is rare to identify them all in the blood. Regarding the origin of the dicentric, among the 30 cases of non-recurrent inv-dup del with sufficient genotyping information, paternal origin was markedly prevalent with consistently identical polymorphisms within the duplication region, regardless of parental origin. The non-random parental origin made any postzygotic origin unlikely and suggested the occurrence of these dicentrics mainly in spermatogenesis. This study strengthens the evidence that non-recurrent de novo structural rearrangements are often secondary to the rescue of a zygotic genome incompatible with embryo survival.
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Affiliation(s)
- Orsetta Zuffardi
- Department of Molecular Medicine, University of Pavia, Pavia, Italy.
| | - Marco Fichera
- Department of Biomedical and Biotechnological Sciences, Medical Genetics, University of Catania, Catania, Italy; Oasi Research Institute-IRCCS, Troina, Italy.
| | - Maria Clara Bonaglia
- Cytogenetics Laboratory, Scientific Institute, IRCCS Eugenio Medea, Bosisio Parini, Lecco, Italy.
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Lange M, Begolli R, Giakountis A. Non-Coding Variants in Cancer: Mechanistic Insights and Clinical Potential for Personalized Medicine. Noncoding RNA 2021; 7:47. [PMID: 34449663 PMCID: PMC8395730 DOI: 10.3390/ncrna7030047] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 07/26/2021] [Accepted: 08/01/2021] [Indexed: 12/11/2022] Open
Abstract
The cancer genome is characterized by extensive variability, in the form of Single Nucleotide Polymorphisms (SNPs) or structural variations such as Copy Number Alterations (CNAs) across wider genomic areas. At the molecular level, most SNPs and/or CNAs reside in non-coding sequences, ultimately affecting the regulation of oncogenes and/or tumor-suppressors in a cancer-specific manner. Notably, inherited non-coding variants can predispose for cancer decades prior to disease onset. Furthermore, accumulation of additional non-coding driver mutations during progression of the disease, gives rise to genomic instability, acting as the driving force of neoplastic development and malignant evolution. Therefore, detection and characterization of such mutations can improve risk assessment for healthy carriers and expand the diagnostic and therapeutic toolbox for the patient. This review focuses on functional variants that reside in transcribed or not transcribed non-coding regions of the cancer genome and presents a collection of appropriate state-of-the-art methodologies to study them.
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Affiliation(s)
- Marios Lange
- Department of Biochemistry and Biotechnology, University of Thessaly, Biopolis, 41500 Larissa, Greece; (M.L.); (R.B.)
| | - Rodiola Begolli
- Department of Biochemistry and Biotechnology, University of Thessaly, Biopolis, 41500 Larissa, Greece; (M.L.); (R.B.)
| | - Antonis Giakountis
- Department of Biochemistry and Biotechnology, University of Thessaly, Biopolis, 41500 Larissa, Greece; (M.L.); (R.B.)
- Institute for Fundamental Biomedical Research, B.S.R.C “Alexander Fleming”, 34 Fleming Str., 16672 Vari, Greece
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Rojano E, Córdoba-Caballero J, Jabato FM, Gallego D, Serrano M, Pérez B, Parés-Aguilar Á, Perkins JR, Ranea JAG, Seoane-Zonjic P. Evaluating, Filtering and Clustering Genetic Disease Cohorts Based on Human Phenotype Ontology Data with Cohort Analyzer. J Pers Med 2021; 11:730. [PMID: 34442375 PMCID: PMC8398478 DOI: 10.3390/jpm11080730] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Revised: 07/13/2021] [Accepted: 07/20/2021] [Indexed: 12/21/2022] Open
Abstract
Exhaustive and comprehensive analysis of pathological traits is essential to understanding genetic diseases, performing precise diagnosis and prescribing personalized treatments. It is particularly important for disease cohorts, as thoroughly detailed phenotypic profiles allow patients to be compared and contrasted. However, many disease cohorts contain patients that have been ascribed low numbers of very general and relatively uninformative phenotypes. We present Cohort Analyzer, a tool that measures the phenotyping quality of patient cohorts. It calculates multiple statistics to give a general overview of the cohort status in terms of the depth and breadth of phenotyping, allowing us to detect less well-phenotyped patients for re-examining or excluding from further analyses. In addition, it performs clustering analysis to find subgroups of patients that share similar phenotypic profiles. We used it to analyse three cohorts of genetic diseases patients with very different properties. We found that cohorts with the most specific and complete phenotypic characterization give more potential insights into the disease than those that were less deeply characterised by forming more informative clusters. For two of the cohorts, we also analysed genomic data related to the patients, and linked the genomic data to the patient-subgroups by mapping shared variants to genes and functions. The work highlights the need for improved phenotyping in this era of personalized medicine. The tool itself is freely available alongside a workflow to allow the analyses shown in this work to be applied to other datasets.
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Affiliation(s)
- Elena Rojano
- Department of Molecular Biology and Biochemistry, University of Málaga, 29071 Málaga, Spain; (E.R.); (J.C.-C.); (Á.P.-A.); (J.A.G.R.); (P.S.-Z.)
- Institute of Biomedical Research in Málaga (IBIMA), 29010 Málaga, Spain;
| | - José Córdoba-Caballero
- Department of Molecular Biology and Biochemistry, University of Málaga, 29071 Málaga, Spain; (E.R.); (J.C.-C.); (Á.P.-A.); (J.A.G.R.); (P.S.-Z.)
| | - Fernando M. Jabato
- Institute of Biomedical Research in Málaga (IBIMA), 29010 Málaga, Spain;
- Supercomputation and Bioinformatics (SCBI), University of Malaga, 29071 Malaga, Spain
- LifeWatch-ERIC, 41071 Seville, Spain
| | - Diana Gallego
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), [Madrid, Málaga, Barcelona], Instituto de Salud Carlos III, 28029 Madrid, Spain; (D.G.); (M.S.); (B.P.)
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biología Molecular-SO UAM-CSIC, Campus de Cantoblanco, Universidad Autónoma de Madrid, 28049 Madrid, Spain
- Instituto de Investigación Sanitaria idiPAZ, 28049 Madrid, Spain
| | - Mercedes Serrano
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), [Madrid, Málaga, Barcelona], Instituto de Salud Carlos III, 28029 Madrid, Spain; (D.G.); (M.S.); (B.P.)
- Neuropediatric Department, Institut de Recerca Hospital Sant Joan de Déu, 08950 Barcelona, Spain
| | - Belén Pérez
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), [Madrid, Málaga, Barcelona], Instituto de Salud Carlos III, 28029 Madrid, Spain; (D.G.); (M.S.); (B.P.)
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biología Molecular-SO UAM-CSIC, Campus de Cantoblanco, Universidad Autónoma de Madrid, 28049 Madrid, Spain
- Instituto de Investigación Sanitaria idiPAZ, 28049 Madrid, Spain
| | - Álvaro Parés-Aguilar
- Department of Molecular Biology and Biochemistry, University of Málaga, 29071 Málaga, Spain; (E.R.); (J.C.-C.); (Á.P.-A.); (J.A.G.R.); (P.S.-Z.)
| | - James R. Perkins
- Department of Molecular Biology and Biochemistry, University of Málaga, 29071 Málaga, Spain; (E.R.); (J.C.-C.); (Á.P.-A.); (J.A.G.R.); (P.S.-Z.)
- Institute of Biomedical Research in Málaga (IBIMA), 29010 Málaga, Spain;
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), [Madrid, Málaga, Barcelona], Instituto de Salud Carlos III, 28029 Madrid, Spain; (D.G.); (M.S.); (B.P.)
| | - Juan A. G. Ranea
- Department of Molecular Biology and Biochemistry, University of Málaga, 29071 Málaga, Spain; (E.R.); (J.C.-C.); (Á.P.-A.); (J.A.G.R.); (P.S.-Z.)
- Institute of Biomedical Research in Málaga (IBIMA), 29010 Málaga, Spain;
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), [Madrid, Málaga, Barcelona], Instituto de Salud Carlos III, 28029 Madrid, Spain; (D.G.); (M.S.); (B.P.)
| | - Pedro Seoane-Zonjic
- Department of Molecular Biology and Biochemistry, University of Málaga, 29071 Málaga, Spain; (E.R.); (J.C.-C.); (Á.P.-A.); (J.A.G.R.); (P.S.-Z.)
- Institute of Biomedical Research in Málaga (IBIMA), 29010 Málaga, Spain;
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), [Madrid, Málaga, Barcelona], Instituto de Salud Carlos III, 28029 Madrid, Spain; (D.G.); (M.S.); (B.P.)
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Mosley TJ, Johnston HR, Cutler DJ, Zwick ME, Mulle JG. Sex-specific recombination patterns predict parent of origin for recurrent genomic disorders. BMC Med Genomics 2021; 14:154. [PMID: 34107974 PMCID: PMC8190997 DOI: 10.1186/s12920-021-00999-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 06/02/2021] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Structural rearrangements of the genome, which generally occur during meiosis and result in large-scale (> 1 kb) copy number variants (CNV; deletions or duplications ≥ 1 kb), underlie genomic disorders. Recurrent pathogenic CNVs harbor similar breakpoints in multiple unrelated individuals and are primarily formed via non-allelic homologous recombination (NAHR). Several pathogenic NAHR-mediated recurrent CNV loci demonstrate biases for parental origin of de novo CNVs. However, the mechanism underlying these biases is not well understood. METHODS We performed a systematic, comprehensive literature search to curate parent of origin data for multiple pathogenic CNV loci. Using a regression framework, we assessed the relationship between parental CNV origin and the male to female recombination rate ratio. RESULTS We demonstrate significant association between sex-specific differences in meiotic recombination and parental origin biases at these loci (p = 1.07 × 10-14). CONCLUSIONS Our results suggest that parental origin of CNVs is largely influenced by sex-specific recombination rates and highlight the need to consider these differences when investigating mechanisms that cause structural variation.
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Affiliation(s)
- Trenell J Mosley
- Graduate Program in Genetics and Molecular Biology, Laney Graduate School, Emory University, 201 Dowman Drive, Atlanta, GA, 30322, USA
- Department of Human Genetics, Emory University School of Medicine, 615 Michael Street, Whitehead Building Suite 300, Atlanta, GA, 30322, USA
| | - H Richard Johnston
- Department of Human Genetics, Emory University School of Medicine, 615 Michael Street, Whitehead Building Suite 300, Atlanta, GA, 30322, USA
- Emory Integrated Computational Core, Emory University, 101 Woodruff Circle, Atlanta, GA, 30322, USA
| | - David J Cutler
- Department of Human Genetics, Emory University School of Medicine, 615 Michael Street, Whitehead Building Suite 300, Atlanta, GA, 30322, USA
| | - Michael E Zwick
- Department of Human Genetics, Emory University School of Medicine, 615 Michael Street, Whitehead Building Suite 300, Atlanta, GA, 30322, USA
- Department of Pediatrics, Emory University School of Medicine, 2015 Uppergate Drive, Atlanta, GA, 30322, USA
| | - Jennifer G Mulle
- Department of Human Genetics, Emory University School of Medicine, 615 Michael Street, Whitehead Building Suite 300, Atlanta, GA, 30322, USA.
- Department of Epidemiology, Rollins School of Public Health, Emory University, 1518 Clifton Road NE, Atlanta, GA, 30322, USA.
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8
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Belyeu JR, Chowdhury M, Brown J, Pedersen BS, Cormier MJ, Quinlan AR, Layer RM. Samplot: a platform for structural variant visual validation and automated filtering. Genome Biol 2021; 22:161. [PMID: 34034781 PMCID: PMC8145817 DOI: 10.1186/s13059-021-02380-5] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 05/10/2021] [Indexed: 12/15/2022] Open
Abstract
Visual validation is an important step to minimize false-positive predictions from structural variant (SV) detection. We present Samplot, a tool for creating images that display the read depth and sequence alignments necessary to adjudicate purported SVs across samples and sequencing technologies. These images can be rapidly reviewed to curate large SV call sets. Samplot is applicable to many biological problems such as SV prioritization in disease studies, analysis of inherited variation, or de novo SV review. Samplot includes a machine learning package that dramatically decreases the number of false positives without human review. Samplot is available at https://github.com/ryanlayer/samplot .
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Affiliation(s)
- Jonathan R Belyeu
- Department of Human Genetics, University of Utah, Salt Lake City, UT, USA
- Utah Center for Genetic Discovery, University of Utah, Salt Lake City, UT, USA
| | - Murad Chowdhury
- BioFrontiers Institute, University of Colorado, Boulder, CO, USA
| | - Joseph Brown
- Department of Human Genetics, University of Utah, Salt Lake City, UT, USA
- Utah Center for Genetic Discovery, University of Utah, Salt Lake City, UT, USA
| | - Brent S Pedersen
- Department of Human Genetics, University of Utah, Salt Lake City, UT, USA
- Utah Center for Genetic Discovery, University of Utah, Salt Lake City, UT, USA
| | - Michael J Cormier
- Department of Human Genetics, University of Utah, Salt Lake City, UT, USA
- Utah Center for Genetic Discovery, University of Utah, Salt Lake City, UT, USA
| | - Aaron R Quinlan
- Department of Human Genetics, University of Utah, Salt Lake City, UT, USA
- Utah Center for Genetic Discovery, University of Utah, Salt Lake City, UT, USA
- Department of Biomedical Informatics, University of Utah, Salt Lake City, UT, USA
| | - Ryan M Layer
- BioFrontiers Institute, University of Colorado, Boulder, CO, USA.
- Department of Computer Science, University of Colorado, Boulder, CO, USA.
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Belyeu JR, Brand H, Wang H, Zhao X, Pedersen BS, Feusier J, Gupta M, Nicholas TJ, Brown J, Baird L, Devlin B, Sanders SJ, Jorde LB, Talkowski ME, Quinlan AR. De novo structural mutation rates and gamete-of-origin biases revealed through genome sequencing of 2,396 families. Am J Hum Genet 2021; 108:597-607. [PMID: 33675682 PMCID: PMC8059337 DOI: 10.1016/j.ajhg.2021.02.012] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 02/12/2021] [Indexed: 01/05/2023] Open
Abstract
Each human genome includes de novo mutations that arose during gametogenesis. While these germline mutations represent a fundamental source of new genetic diversity, they can also create deleterious alleles that impact fitness. Whereas the rate and patterns of point mutations in the human germline are now well understood, far less is known about the frequency and features that impact de novo structural variants (dnSVs). We report a family-based study of germline mutations among 9,599 human genomes from 33 multigenerational CEPH-Utah families and 2,384 families from the Simons Foundation Autism Research Initiative. We find that de novo structural mutations detected by alignment-based, short-read WGS occur at an overall rate of at least 0.160 events per genome in unaffected individuals, and we observe a significantly higher rate (0.206 per genome) in ASD-affected individuals. In both probands and unaffected samples, nearly 73% of de novo structural mutations arose in paternal gametes, and we predict most de novo structural mutations to be caused by mutational mechanisms that do not require sequence homology. After multiple testing correction, we did not observe a statistically significant correlation between parental age and the rate of de novo structural variation in offspring. These results highlight that a spectrum of mutational mechanisms contribute to germline structural mutations and that these mechanisms most likely have markedly different rates and selective pressures than those leading to point mutations.
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Affiliation(s)
- Jonathan R Belyeu
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
| | - Harrison Brand
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA; Program in Medical and Population Genetics and Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, Cambridge, MA 02114, USA
| | - Harold Wang
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA; Program in Medical and Population Genetics and Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, Cambridge, MA 02114, USA
| | - Xuefang Zhao
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA; Program in Medical and Population Genetics and Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, Cambridge, MA 02114, USA
| | - Brent S Pedersen
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
| | - Julie Feusier
- Huntsman Cancer Institute, University of Utah, Salt Lake City, UT 84112, USA
| | - Meenal Gupta
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
| | - Thomas J Nicholas
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
| | - Joseph Brown
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
| | - Lisa Baird
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
| | - Bernie Devlin
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Stephan J Sanders
- Department of Psychiatry, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94143, USA; Institute for Human Genetics, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Lynn B Jorde
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA; Utah Center for Genetic Discovery, University of Utah, Salt Lake City, UT 84112, USA
| | - Michael E Talkowski
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA; Program in Medical and Population Genetics and Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, Cambridge, MA 02114, USA.
| | - Aaron R Quinlan
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA; Department of Biomedical Informatics, University of Utah, Salt Lake City, UT 84112, USA; Utah Center for Genetic Discovery, University of Utah, Salt Lake City, UT 84112, USA.
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10
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Torra R, Furlano M, Ortiz A, Ars E. Genetic kidney diseases as an underrecognized cause of chronic kidney disease: the key role of international registry reports. Clin Kidney J 2021; 14:1879-1885. [PMID: 34345410 PMCID: PMC8323147 DOI: 10.1093/ckj/sfab056] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Indexed: 01/01/2023] Open
Abstract
Inherited kidney diseases (IKDs) are among the leading causes of early-onset chronic kidney disease (CKD) and are responsible for at least 10-15% of cases of kidney replacement therapy (KRT) in adults. Paediatric nephrologists are very aware of the high prevalence of IKDs among their patients, but this is not the case for adult nephrologists. Recent publications have demonstrated that monogenic diseases account for a significant percentage of adult cases of CKD. A substantial number of these patients have received a non-specific/incorrect diagnosis or a diagnosis of CKD of unknown aetiology, which precludes correct treatment, follow-up and genetic counselling. There are a number of reasons why genetic kidney diseases are difficult to diagnose in adulthood: (i) adult nephrologists, in general, are not knowledgeable about IKDs; (ii) existence of atypical phenotypes; (iii) genetic testing is not universally available; (iv) family history is not always available or may be negative; (v) lack of knowledge of various genotype-phenotype relationships and (vi) conflicting interpretation of the pathogenicity of many sequence variants. Registries can contribute to visualize the burden of IKDs by regularly grouping all IKDs in their annual reports, as is done for glomerulonephritis or interstitial diseases, rather than reporting only cystic disease and hiding other IKDs under labels such as 'miscellaneous' or 'other'. Any effort to reduce the percentage of patients needing KRT with a diagnosis of 'nephropathy of unknown etiology' or an unspecific/incorrect diagnosis should be encouraged as a step towards precision nephrology. Genetic testing may be of value in this context but should not be used indiscriminately, but rather on the basis of a deep knowledge of IKDs.
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Affiliation(s)
- Roser Torra
- Department of Nephrology, Inherited Kidney Diseases, Fundació Puigvert, Instituto de Investigaciones Biomédicas Sant Pau (IIB-Sant Pau), Medicine Department-Universitat Autónoma de Barcelona, REDinREN, Instituto de Investigación Carlos III, Barcelona, Spain
| | - Mónica Furlano
- Department of Nephrology, Inherited Kidney Diseases, Fundació Puigvert, Instituto de Investigaciones Biomédicas Sant Pau (IIB-Sant Pau), Medicine Department-Universitat Autónoma de Barcelona, REDinREN, Instituto de Investigación Carlos III, Barcelona, Spain
| | - Alberto Ortiz
- IIS-Fundación Jimenez Diaz, School of Medicine, Universidad Autónoma de Madrid, Fundación Renal Iñigo Alvarez de Toledo-IRSIN, REDinREN, Instituto de Investigación Carlos III, Madrid, Spain
| | - Elisabet Ars
- Molecular Biology Laboratory, Fundació Puigvert, Instituto de Investigaciones Biomédicas Sant Pau (IIB-Sant Pau), Universitat Autónoma de Barcelona, REDinREN, Instituto de Investigación Carlos III, Barcelona, Spain
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11
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Cocchi E, Nestor JG, Gharavi AG. Clinical Genetic Screening in Adult Patients with Kidney Disease. Clin J Am Soc Nephrol 2020; 15:1497-1510. [PMID: 32646915 PMCID: PMC7536756 DOI: 10.2215/cjn.15141219] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Expanded accessibility of genetic sequencing technologies, such as chromosomal microarray and massively parallel sequencing approaches, is changing the management of hereditary kidney diseases. Genetic causes account for a substantial proportion of pediatric kidney disease cases, and with increased utilization of diagnostic genetic testing in nephrology, they are now also detected at appreciable frequencies in adult populations. Establishing a molecular diagnosis can have many potential benefits for patient care, such as guiding treatment, familial testing, and providing deeper insights on the molecular pathogenesis of kidney diseases. Today, with wider clinical use of genetic testing as part of the diagnostic evaluation, nephrologists have the challenging task of selecting the most suitable genetic test for each patient, and then applying the results into the appropriate clinical contexts. This review is intended to familiarize nephrologists with the various technical, logistical, and ethical considerations accompanying the increasing utilization of genetic testing in nephrology care.
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Affiliation(s)
- Enrico Cocchi
- Division of Nephrology and Center for Precision Medicine and Genomics, Department of Medicine, Columbia University, New York, New York
- Department of Pediatrics, Universita' degli Studi di Torino, Torino, Italy
| | - Jordan Gabriela Nestor
- Division of Nephrology and Center for Precision Medicine and Genomics, Department of Medicine, Columbia University, New York, New York
| | - Ali G Gharavi
- Division of Nephrology and Center for Precision Medicine and Genomics, Department of Medicine, Columbia University, New York, New York
- Insititute of Genomic Medicine, Columbia University, New York, New York
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12
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Chalas C, Receveur A, Frydman N, Massin N, Tachdjian G, Drouineaud V, Benachi A, Patrat C, Petit FM. A case of germline mosaicism for a 7q32.1q33 deletion in a sperm donor: consequences on pregnancy follow-up and recommendations. Basic Clin Androl 2020; 30:14. [PMID: 33024563 PMCID: PMC7532087 DOI: 10.1186/s12610-020-00113-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 08/24/2020] [Indexed: 01/23/2023] Open
Abstract
Background Germline mosaicism is considered to be a rare event. However, its occurrence is underestimated due to the limited availability of germ cells. The genomic variations that underlie this phenomenon comprise single nucleotide polymorphism (SNPs), copy number variations (CNVs) and aneuploidies. In the case of CNVs, deletions are more frequent in the paternal germline while duplications are more commonly maternal in origin. Germline mosaicism increases with paternal age as the risk of SNPs increase with the number of germ cell divisions. We here report a case of germline mosaicism in the spermatozoa of a donor that resulted in one pathological pregnancy. Results Straws from the same sperm donor were provided to seven recipient couples, resulting in four pregnancies. Second trimester ultrasound analysis revealed bilateral talipes equinovarus associated with growth retardation in one of these pregnancies. Array-comparative genomic hybridization (CGH) carried out after amniocentesis revealed a 4 Mb deletion in the 7q32.1q33 region. The blood karyotypes and array-CGHs were normal in the mother, as well as in the donor. However, the microsatellite profile indicated a paternal origin. Fluorescent in situ hybridization (FISH) analysis of the donor’s spermatozoa revealed the same chromosomal rearrangements in 12% of the spermatozoa population. Due to the documented risk of mental retardation associated with genomic rearrangements in the same region, the couple decided to terminate the pregnancy. Amniocentesis was performed in the other couples, which yielded normal FISH analysis results. Conclusions Several cases of germline mosaicism have been reported to date, but their frequency is probably underestimated. Moreover, it is important to note that germline mosaicism cannot be ruled out by conventional cytogenetic screening of blood cells. This case highlights the need for close follow-up of every pregnancy obtained through gamete donation, given that the occurrence of germline mosaicism may have major consequences when multiple pregnancies are obtained concomitantly.
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Affiliation(s)
- Celine Chalas
- Laboratoire d'Histologie-Embryologie-Biologie de la Reproduction - CECOS, Hôpital Cochin, AP-HP, Centre Université de Paris, F-75014 Paris, France
| | - Aline Receveur
- Laboratoire de cytogénomique, Hôpital Antoine Béclère, AP-HP, Université Paris Saclay, cedex, F-92141 Clamart, France
| | - Nelly Frydman
- Laboratoire d'Histologie-Embryologie-Cytogenetique- CECOS, Hôpital Antoine Béclère, AP-HP, Université Paris Saclay, cedex, F-92141 Clamart, France.,Faculté de médecine de Bicêtre, Université Paris-Saclay, F-94270 Le Kremlin Bicêtre, France
| | - Nathalie Massin
- Service de gynécologie et obstétrique, Centre Hospitalier Intercommunal, F-94010 Créteil, France
| | - Gerard Tachdjian
- Laboratoire de cytogénomique, Hôpital Antoine Béclère, AP-HP, Université Paris Saclay, cedex, F-92141 Clamart, France.,Laboratoire d'Histologie-Embryologie-Cytogenetique- CECOS, Hôpital Antoine Béclère, AP-HP, Université Paris Saclay, cedex, F-92141 Clamart, France.,Faculté de médecine de Bicêtre, Université Paris-Saclay, F-94270 Le Kremlin Bicêtre, France
| | - Veronique Drouineaud
- Laboratoire d'Histologie-Embryologie-Biologie de la Reproduction - CECOS, Hôpital Cochin, AP-HP, Centre Université de Paris, F-75014 Paris, France
| | - Alexandra Benachi
- Faculté de médecine de Bicêtre, Université Paris-Saclay, F-94270 Le Kremlin Bicêtre, France.,Service de gynécologie et obstétrique, Hôpital Antoine Béclère, AP-HP, Université Paris Saclay, cedex, F-92141 Clamart, France
| | - Catherine Patrat
- Laboratoire d'Histologie-Embryologie-Biologie de la Reproduction - CECOS, Hôpital Cochin, AP-HP, Centre Université de Paris, F-75014 Paris, France.,Université de Paris, U 1016, Institut Cochin, F-75014 Paris, France
| | - Francois Michael Petit
- Laboratoire de génétique moléculaire, Hôpital Antoine Béclère, AP-HP, Université Paris Saclay, cedex, F-92141 Clamart, France
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13
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Oota S. Somatic mutations - Evolution within the individual. Methods 2019; 176:91-98. [PMID: 31711929 DOI: 10.1016/j.ymeth.2019.11.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Revised: 10/31/2019] [Accepted: 11/07/2019] [Indexed: 02/08/2023] Open
Abstract
With the rapid advancement of sequencing technologies over the last two decades, it is becoming feasible to detect rare variants from somatic tissue samples. Studying such somatic mutations can provide deep insights into various senescence-related diseases, including cancer, inflammation, and sporadic psychiatric disorders. While it is still a difficult task to identify true somatic mutations, relentless efforts to combine experimental and computational methods have made it possible to obtain reliable data. Furthermore, state-of-the-art machine learning approaches have drastically improved the efficiency and sensitivity of these methods. Meanwhile, we can regard somatic mutations as a counterpart of germline mutations, and it is possible to apply well-formulated mathematical frameworks developed for population genetics and molecular evolution to analyze this 'somatic evolution'. For example, retrospective cell lineage tracing is a promising technique to elucidate the mechanism of pre-diseases using single-cell RNA-sequencing (scRNA-seq) data.
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Affiliation(s)
- Satoshi Oota
- Image Processing Research Team, Center for Advanced Photonics, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
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14
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Refining the Phenotype of Recurrent Rearrangements of Chromosome 16. Int J Mol Sci 2019; 20:ijms20051095. [PMID: 30836598 PMCID: PMC6429492 DOI: 10.3390/ijms20051095] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 02/25/2019] [Accepted: 02/27/2019] [Indexed: 01/08/2023] Open
Abstract
Chromosome 16 is one of the most gene-rich chromosomes of our genome, and 10% of its sequence consists of segmental duplications, which give instability and predisposition to rearrangement by the recurrent mechanism of non-allelic homologous recombination. Microarray technologies have allowed for the analysis of copy number variations (CNVs) that can contribute to the risk of developing complex diseases. By array comparative genomic hybridization (CGH) screening of 1476 patients, we detected 27 cases with CNVs on chromosome 16. We identified four smallest regions of overlapping (SROs): one at 16p13.11 was found in seven patients; one at 16p12.2 was found in four patients; two close SROs at 16p11.2 were found in twelve patients; finally, six patients were found with atypical rearrangements. Although phenotypic variability was observed, we identified a male bias for Childhood Apraxia of Speech associated to 16p11.2 microdeletions. We also reported an elevated frequency of second-site genomic alterations, supporting the model of the second hit to explain the clinical variability associated with CNV syndromes. Our goal was to contribute to the building of a chromosome 16 disease-map based on disease susceptibility regions. The role of the CNVs of chromosome 16 was increasingly made clear in the determination of developmental delay. We also found that in some cases a second-site CNV could explain the phenotypic heterogeneity by a simple additive effect or a pejorative synergistic effect.
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15
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Genetic Instability and Chromatin Remodeling in Spermatids. Genes (Basel) 2019; 10:genes10010040. [PMID: 30646585 PMCID: PMC6356297 DOI: 10.3390/genes10010040] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 01/04/2019] [Accepted: 01/08/2019] [Indexed: 12/13/2022] Open
Abstract
The near complete replacement of somatic chromatin in spermatids is, perhaps, the most striking nuclear event known to the eukaryotic domain. The process is far from being fully understood, but research has nevertheless unraveled its complexity as an expression of histone variants and post-translational modifications that must be finely orchestrated to promote the DNA topological change and compaction provided by the deposition of protamines. That this major transition may not be genetically inert came from early observations that transient DNA strand breaks were detected in situ at chromatin remodeling steps. The potential for genetic instability was later emphasized by our demonstration that a significant number of DNA double-strand breaks (DSBs) are formed and then repaired in the haploid context of spermatids. The detection of DNA breaks by 3'OH end labeling in the whole population of spermatids suggests that a reversible enzymatic process is involved, which differs from canonical apoptosis. We have set the stage for a better characterization of the genetic impact of this transition by showing that post-meiotic DNA fragmentation is conserved from human to yeast, and by providing tools for the initial mapping of the genome-wide DSB distribution in the mouse model. Hence, the molecular mechanism of post-meiotic DSB formation and repair in spermatids may prove to be a significant component of the well-known male mutation bias. Based on our recent observations and a survey of the literature, we propose that the chromatin remodeling in spermatids offers a proper context for the induction of de novo polymorphism and structural variations that can be transmitted to the next generation.
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16
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Pronounced maternal parent-of-origin bias for type-1 NF1 microdeletions. Hum Genet 2018; 137:365-373. [PMID: 29730711 DOI: 10.1007/s00439-018-1888-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 04/24/2018] [Indexed: 01/02/2023]
Abstract
Neurofibromatosis type 1 (NF1) is caused, in 4.7-11% of cases, by large deletions encompassing the NF1 gene and its flanking regions within 17q11.2. Different types of large NF1 deletion occur which are distinguishable by their breakpoint location and underlying mutational mechanism. Most common are the type-1 NF1 deletions of 1.4 Mb which exhibit recurrent breakpoints caused by nonallelic homologous recombination (NAHR), also termed unequal crossover. Here, we analyzed 37 unrelated families of patients with de novo type-1 NF1 deletions by means of short tandem repeat (STR) profiling to determine the parental origin of the deletions. We observed that 33 of the 37 type-1 deletions were of maternal origin (89.2% of cases; p < 0.0001). Analysis of the patients' siblings indicated that, in 14 informative cases, ten (71.4%) deletions resulted from interchromosomal unequal crossover during meiosis I. Our findings indicate a strong maternal parent-of-origin bias for type-1 NF1 deletions. A similarly pronounced maternal transmission bias has been reported for recurrent copy number variants (CNVs) within 16p11.2 associated with autism, but not so far for any other NAHR-mediated pathogenic CNVs. Region-specific genomic features are likely to be responsible for the maternal bias in the origin of both the 16p11.2 CNVs and type-1 NF1 deletions.
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17
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Nestor JG, Groopman EE, Gharavi AG. Towards precision nephrology: the opportunities and challenges of genomic medicine. J Nephrol 2017; 31:47-60. [PMID: 29043570 DOI: 10.1007/s40620-017-0448-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 10/10/2017] [Indexed: 12/28/2022]
Abstract
The expansion of genomic medicine is furthering our understanding of many human diseases. This is well illustrated in the field of nephrology, through the characterization, discovery, and growing insight into various renal diseases through use of Next Generation Sequencing (NGS) technologies. This review will provide an overview of the diagnostic opportunities of using genetic testing in the clinical setting by describing notable discoveries regarding inherited forms of renal disease that have advanced the field and by highlighting some of the potential benefits of establishing a molecular diagnosis in a clinical practice. In addition, it will discuss some of the challenges associated with the expansion of genetic testing into the clinical setting, including clinical variant interpretation and return of genetic results.
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Affiliation(s)
- Jordan G Nestor
- Division of Nephrology, Department of Medicine, College of Physicians and Surgeons, Columbia University, 1150 St. Nicholas Ave, Room 413, New York, NY, 10032, USA
| | - Emily E Groopman
- Division of Nephrology, Department of Medicine, College of Physicians and Surgeons, Columbia University, 1150 St. Nicholas Ave, Room 413, New York, NY, 10032, USA
| | - Ali G Gharavi
- Division of Nephrology, Department of Medicine, College of Physicians and Surgeons, Columbia University, 1150 St. Nicholas Ave, Room 413, New York, NY, 10032, USA.
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