1
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Kerkhof J, Rastin C, Levy MA, Relator R, McConkey H, Demain L, Dominguez-Garrido E, Kaat LD, Houge SD, DuPont BR, Fee T, Fletcher RS, Gokhale D, Haukanes BI, Henneman P, Hilton S, Hilton BA, Jenkinson S, Lee JA, Louie RJ, Motazacker MM, Rzasa J, Stevenson RE, Plomp A, van der Laan L, van der Smagt J, Walden KK, Banka S, Mannens M, Skinner SA, Friez MJ, Campbell C, Tedder ML, Alders M, Sadikovic B. Diagnostic utility and reporting recommendations for clinical DNA methylation episignature testing in genetically undiagnosed rare diseases. Genet Med 2024; 26:101075. [PMID: 38251460 DOI: 10.1016/j.gim.2024.101075] [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: 08/29/2023] [Revised: 01/09/2024] [Accepted: 01/12/2024] [Indexed: 01/23/2024] Open
Abstract
PURPOSE This study aims to assess the diagnostic utility and provide reporting recommendations for clinical DNA methylation episignature testing based on the cohort of patients tested through the EpiSign Clinical Testing Network. METHODS The EpiSign assay utilized unsupervised clustering techniques and a support vector machine-based classification algorithm to compare each patient's genome-wide DNA methylation profile with the EpiSign Knowledge Database, yielding the result that was reported. An international working group, representing distinct EpiSign Clinical Testing Network health jurisdictions, collaborated to establish recommendations for interpretation and reporting of episignature testing. RESULTS Among 2399 cases analyzed, 1667 cases underwent a comprehensive screen of validated episignatures, imprinting, and promoter regions, resulting in 18.7% (312/1667) positive reports. The remaining 732 referrals underwent targeted episignature analysis for assessment of sequence or copy-number variants (CNVs) of uncertain significance or for assessment of clinical diagnoses without confirmed molecular findings, and 32.4% (237/732) were positive. Cases with detailed clinical information were highlighted to describe various utility scenarios for episignature testing. CONCLUSION Clinical DNA methylation testing including episignatures, imprinting, and promoter analysis provided by an integrated network of clinical laboratories enables test standardization and demonstrates significant diagnostic yield and clinical utility beyond DNA sequence analysis in rare diseases.
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Affiliation(s)
- Jennifer Kerkhof
- Verspeeten Clinical Genome Centre, London Health Sciences Centre, London, ON, Canada
| | - Cassandra Rastin
- Verspeeten Clinical Genome Centre, London Health Sciences Centre, London, ON, Canada
| | - Michael A Levy
- Verspeeten Clinical Genome Centre, London Health Sciences Centre, London, ON, Canada
| | - Raissa Relator
- Verspeeten Clinical Genome Centre, London Health Sciences Centre, London, ON, Canada
| | - Haley McConkey
- Verspeeten Clinical Genome Centre, London Health Sciences Centre, London, ON, Canada
| | - Leigh Demain
- Manchester Centre for Genomic Medicine, Manchester University NHS Foundation Trust, Manchester, United Kingdom
| | | | - Laura Donker Kaat
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Sofia Douzgou Houge
- Haukeland University Hospital, Centre for Medical Genetics and Molecular Medicine, Bergen, Norway
| | | | | | | | - David Gokhale
- Manchester Centre for Genomic Medicine, Manchester University NHS Foundation Trust, Manchester, United Kingdom
| | - Bjørn Ivar Haukanes
- Haukeland University Hospital, Centre for Medical Genetics and Molecular Medicine, Bergen, Norway
| | - Peter Henneman
- Amsterdam University Medical Center, University of Amsterdam, Department of Human Genetics, Amsterdam Reproduction and Development Research Institute, Amsterdam, The Netherlands
| | - Sarah Hilton
- Manchester Centre for Genomic Medicine, Manchester University NHS Foundation Trust, Manchester, United Kingdom
| | | | - Sarah Jenkinson
- Manchester Centre for Genomic Medicine, Manchester University NHS Foundation Trust, Manchester, United Kingdom
| | | | | | - M Mahdi Motazacker
- Amsterdam University Medical Center, University of Amsterdam, Department of Human Genetics, Amsterdam Reproduction and Development Research Institute, Amsterdam, The Netherlands
| | - Jessica Rzasa
- Verspeeten Clinical Genome Centre, London Health Sciences Centre, London, ON, Canada
| | | | - Astrid Plomp
- Department of Clinical Genetics, AMC, Amsterdam, The Netherlands
| | - Liselot van der Laan
- Amsterdam University Medical Center, University of Amsterdam, Department of Human Genetics, Amsterdam Reproduction and Development Research Institute, Amsterdam, The Netherlands
| | - Jasper van der Smagt
- Department of Genetics, Utrecht University Medical Center, Utrecht, The Netherlands
| | | | - Siddharth Banka
- Manchester Centre for Genomic Medicine, Manchester University NHS Foundation Trust, Manchester, United Kingdom; Division of Evolution, Infection and Genomic Sciences, School of Biological Sciences, University of Manchester, Manchester, United Kingdom
| | - Marcel Mannens
- Amsterdam University Medical Center, University of Amsterdam, Department of Human Genetics, Amsterdam Reproduction and Development Research Institute, Amsterdam, The Netherlands
| | | | | | - Christopher Campbell
- Manchester Centre for Genomic Medicine, Manchester University NHS Foundation Trust, Manchester, United Kingdom
| | | | - Marielle Alders
- Amsterdam University Medical Center, University of Amsterdam, Department of Human Genetics, Amsterdam Reproduction and Development Research Institute, Amsterdam, The Netherlands
| | - Bekim Sadikovic
- Verspeeten Clinical Genome Centre, London Health Sciences Centre, London, ON, Canada; Department of Pathology and Laboratory Medicine, Western University, London, ON, Canada.
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2
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Kim HY, Shin CH, Shin CH, Ko JM. Uncovering the phenotypic consequences of multi-locus imprinting disturbances using genome-wide methylation analysis in genomic imprinting disorders. PLoS One 2023; 18:e0290450. [PMID: 37594968 PMCID: PMC10437897 DOI: 10.1371/journal.pone.0290450] [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: 02/13/2023] [Accepted: 08/09/2023] [Indexed: 08/20/2023] Open
Abstract
Imprinted genes are regulated by DNA methylation of imprinted differentially methylated regions (iDMRs). An increasing number of patients with congenital imprinting disorders (IDs) exhibit aberrant methylation at multiple imprinted loci, multi-locus imprinting disturbance (MLID). We examined MLID and its possible impact on clinical features in patients with IDs. Genome-wide DNA methylation analysis (GWMA) using blood leukocyte DNA was performed on 13 patients with Beckwith-Wiedemann syndrome (BWS), two patients with Silver-Russell syndrome (SRS), and four controls. HumanMethylation850 BeadChip analysis for 77 iDMRs (809 CpG sites) identified three patients with BWS and one patient with SRS showing additional hypomethylation, other than the disease-related iDMRs, suggestive of MLID. Two regions were aberrantly methylated in at least two patients with BWS showing MLID: PPIEL locus (chromosome 1: 39559298 to 39559744), and FAM50B locus (chromosome 6: 3849096 to 3849469). All patients with BWS- and SRS-MLID did not show any other clinical characteristics associated with additional involved iDMRs. Exome analysis in three patients with BWS who exhibited multiple hypomethylation did not identify any causative variant related to MLID. This study indicates that a genome-wide approach can unravel MLID in patients with an apparently isolated ID. Patients with MLID showed only clinical features related to the original IDs. Long-term follow-up studies in larger cohorts are warranted to evaluate any possible phenotypic consequences of other disturbed imprinted loci.
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Affiliation(s)
- Hwa Young Kim
- Department of Pediatrics, Division of Pediatric Endocrinology and Metabolism, Seoul National University Bundang Hospital, Seongnam, Korea
| | - Choong Ho Shin
- Department of Pediatrics, Division of Pediatric Endocrinology and Metabolism, Seoul National University College of Medicine, Seoul, Korea
| | - Chang Ho Shin
- Department of Orthopaedics, Division of Pediatric Orthopedics, Seoul National University College of Medicine, Seoul, Korea
| | - Jung Min Ko
- Department of Pediatrics, Division of Clinical Genetics, Seoul National University College of Medicine, Seoul, Korea
- Rare Disease Center, Seoul National University Hospital, Seoul, Korea
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3
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LaSalle JM. Epigenomic signatures reveal mechanistic clues and predictive markers for autism spectrum disorder. Mol Psychiatry 2023; 28:1890-1901. [PMID: 36650278 PMCID: PMC10560404 DOI: 10.1038/s41380-022-01917-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 12/05/2022] [Accepted: 12/09/2022] [Indexed: 01/18/2023]
Abstract
Autism spectrum disorder (ASD) comprises a heterogeneous group of neurodevelopmental outcomes in children with a commonality in deficits in social communication and language combined with repetitive behaviors and interests. The etiology of ASD is heterogeneous, as several hundred genes have been implicated as well as multiple in utero environmental exposures. Over the past two decades, epigenetic investigations, including DNA methylation, have emerged as a novel way to capture the complex interface of multivariate ASD etiologies. More recently, epigenome-wide association studies using human brain and surrogate accessible tissues have revealed some convergent genes that are epigenetically altered in ASD, many of which overlap with known genetic risk factors. Unlike transcriptomes, epigenomic signatures defined by DNA methylation from surrogate tissues such as placenta and cord blood can reflect past differences in fetal brain gene transcription, transcription factor binding, and chromatin. For example, the discovery of NHIP (neuronal hypoxia inducible, placenta associated) through an epigenome-wide association in placenta, identified a common genetic risk for ASD that was modified by prenatal vitamin use. While epigenomic signatures are distinct between different genetic syndromic causes of ASD, bivalent chromatin and some convergent gene pathways are consistently epigenetically altered in both syndromic and idiopathic ASD, as well as some environmental exposures. Together, these epigenomic signatures hold promising clues towards improved early prediction and prevention of ASD as well genes and gene pathways to target for pharmacological interventions. Future advancements in single cell and multi-omic technologies, machine learning, as well as non-invasive screening of epigenomic signatures during pregnancy or newborn periods are expected to continue to impact the translatability of the recent discoveries in epigenomics to precision public health.
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Affiliation(s)
- Janine M LaSalle
- Department of Medical Microbiology and Immunology, Perinatal Origins of Disparities Center, MIND Institute, Genome Center, Environmental Health Sciences Center, University of California Davis, Davis, CA, USA.
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4
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van der Laan L, Rooney K, Trooster TM, Mannens MM, Sadikovic B, Henneman P. DNA methylation episignatures: insight into copy number variation. Epigenomics 2022; 14:1373-1388. [PMID: 36537268 DOI: 10.2217/epi-2022-0287] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
In this review we discuss epigenetic disorders that result from aberrations in genes linked to epigenetic regulation. We describe current testing methods for the detection of copy number variants (CNVs) in Mendelian disorders, dosage sensitivity, reciprocal phenotypes and the challenges of test selection and overlapping clinical features in genetic diagnosis. We discuss aberrations of DNA methylation and propose a role for episignatures as a novel clinical testing method in CNV disorders. Finally, we postulate that episignature mapping in CNV disorders may provide novel insights into the molecular mechanisms of disease and unlock key findings of the genome-wide impact on disease gene networks.
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Affiliation(s)
- Liselot van der Laan
- Department of Human Genetics, Amsterdam Reproduction & Development Research Institute, Amsterdam University Medical Centers, Amsterdam, 1105 AZ, The Netherlands
| | - Kathleen Rooney
- Department of Pathology & Laboratory Medicine, Western University, London, Ontario, N5A 3K7, Canada.,Verspeeten Clinical Genome Centre, London Health Science Centre, London, Ontario, N6A 5W9, Canada
| | - Tessa Ma Trooster
- Department of Human Genetics, Amsterdam Reproduction & Development Research Institute, Amsterdam University Medical Centers, Amsterdam, 1105 AZ, The Netherlands
| | - Marcel Mam Mannens
- Department of Human Genetics, Amsterdam Reproduction & Development Research Institute, Amsterdam University Medical Centers, Amsterdam, 1105 AZ, The Netherlands
| | - Bekim Sadikovic
- Department of Pathology & Laboratory Medicine, Western University, London, Ontario, N5A 3K7, Canada.,Verspeeten Clinical Genome Centre, London Health Science Centre, London, Ontario, N6A 5W9, Canada
| | - Peter Henneman
- Department of Human Genetics, Amsterdam Reproduction & Development Research Institute, Amsterdam University Medical Centers, Amsterdam, 1105 AZ, The Netherlands
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5
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Rooney K, Sadikovic B. DNA Methylation Episignatures in Neurodevelopmental Disorders Associated with Large Structural Copy Number Variants: Clinical Implications. Int J Mol Sci 2022; 23:ijms23147862. [PMID: 35887210 PMCID: PMC9324454 DOI: 10.3390/ijms23147862] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 07/11/2022] [Accepted: 07/14/2022] [Indexed: 02/06/2023] Open
Abstract
Large structural chromosomal deletions and duplications, referred to as copy number variants (CNVs), play a role in the pathogenesis of neurodevelopmental disorders (NDDs) through effects on gene dosage. This review focuses on our current understanding of genomic disorders that arise from large structural chromosome rearrangements in patients with NDDs, as well as difficulties in overlap of clinical presentation and molecular diagnosis. We discuss the implications of epigenetics, specifically DNA methylation (DNAm), in NDDs and genomic disorders, and consider the implications and clinical impact of copy number and genomic DNAm testing in patients with suspected genetic NDDs. We summarize evidence of global methylation episignatures in CNV-associated disorders that can be used in the diagnostic pathway and may provide insights into the molecular pathogenesis of genomic disorders. Finally, we discuss the potential for combining CNV and DNAm assessment into a single diagnostic assay.
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Affiliation(s)
- Kathleen Rooney
- Department of Pathology and Laboratory Medicine, Western University, London, ON N6A 3K7, Canada;
- Verspeeten Clinical Genome Centre, London Health Sciences Centre, London, ON N6A 5W9, Canada
| | - Bekim Sadikovic
- Department of Pathology and Laboratory Medicine, Western University, London, ON N6A 3K7, Canada;
- Verspeeten Clinical Genome Centre, London Health Sciences Centre, London, ON N6A 5W9, Canada
- Correspondence: ; Tel.: +1-519-685-8500 (ext. 53074)
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6
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Montano C, Britton JF, Harris JR, Kerkhof J, Barnes BT, Lee JA, Sadikovic B, Sobreira N, Fahrner JA. Genome-wide DNA methylation profiling confirms a case of low-level mosaic Kabuki syndrome 1. Am J Med Genet A 2022; 188:2217-2225. [PMID: 35384273 PMCID: PMC9321966 DOI: 10.1002/ajmg.a.62754] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 01/22/2022] [Accepted: 03/18/2022] [Indexed: 12/27/2022]
Abstract
Kabuki syndrome is a Mendelian disorder of the epigenetic machinery characterized by typical dysmorphic features, intellectual disability, and postnatal growth deficiency. Pathogenic variants in the genes encoding the chromatin modifiers KMT2D and KDM6A are responsible for Kabuki syndrome 1 (KS1) and Kabuki syndrome 2 (KS2), respectively. In addition, 11 cases of KS1 caused by mosaic variants in KMT2D have been reported in the literature. Some of these individuals display milder craniofacial and growth phenotypes, and most do not have congenital heart defects. We report the case of an infant with severe hypoplastic left heart syndrome with mitral atresia and aortic atresia (HLHS MA-AA), pulmonary vein stenosis, and atypical facies with a somatic mosaic de novo nonsense variant in KMT2D (c.8200C>T, p.R2734*) identified on trio exome sequencing of peripheral blood and present in 11.2% of sequencing reads. KS was confirmed with EpiSign, a diagnostic genome-wide DNA methylation platform used to identify epigenetic signatures. This case suggests that use of this newly available clinical test can guide the interpretation of low-level mosaic variants identified through sequencing and suggests a new lower limit of mosaicism in whole blood required for a diagnosis of KS.
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Affiliation(s)
- Carolina Montano
- National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Jacquelyn F Britton
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Jacqueline R Harris
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Department of Neurogenetics, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Jennifer Kerkhof
- Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, Ontario, Canada
| | - Benjamin T Barnes
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Jennifer A Lee
- Greenwood Genetic Center, Greenwood, South Carolina, USA
| | - Bekim Sadikovic
- Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, Ontario, Canada.,Department of Pathology and Laboratory Medicine, Western University, London, Ontario, Canada
| | - Nara Sobreira
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Jill A Fahrner
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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7
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Nothof SA, Magdinier F, Van-Gils J. Chromatin Structure and Dynamics: Focus on Neuronal Differentiation and Pathological Implication. Genes (Basel) 2022; 13:genes13040639. [PMID: 35456445 PMCID: PMC9029427 DOI: 10.3390/genes13040639] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 03/28/2022] [Accepted: 03/31/2022] [Indexed: 02/07/2023] Open
Abstract
Chromatin structure is an essential regulator of gene expression. Its state of compaction contributes to the regulation of genetic programs, in particular during differentiation. Epigenetic processes, which include post-translational modifications of histones, DNA methylation and implication of non-coding RNA, are powerful regulators of gene expression. Neurogenesis and neuronal differentiation are spatio-temporally regulated events that allow the formation of the central nervous system components. Here, we review the chromatin structure and post-translational histone modifications associated with neuronal differentiation. Studying the impact of histone modifications on neuronal differentiation improves our understanding of the pathophysiological mechanisms of chromatinopathies and opens up new therapeutic avenues. In addition, we will discuss techniques for the analysis of histone modifications on a genome-wide scale and the pathologies associated with the dysregulation of the epigenetic machinery.
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Affiliation(s)
- Sophie A. Nothof
- Marseille Medical Genetics, Aix Marseille University, Inserm, CEDEX 05, 13385 Marseille, France; (S.A.N.); (F.M.)
| | - Frédérique Magdinier
- Marseille Medical Genetics, Aix Marseille University, Inserm, CEDEX 05, 13385 Marseille, France; (S.A.N.); (F.M.)
| | - Julien Van-Gils
- Marseille Medical Genetics, Aix Marseille University, Inserm, CEDEX 05, 13385 Marseille, France; (S.A.N.); (F.M.)
- Reference Center AD SOOR, AnDDI-RARE, Inserm U 1211, Medical Genetics Department, Bordeaux University, Center Hospitalier Universitaire de Bordeaux, 33076 Bordeaux, France
- Correspondence:
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8
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Sadikovic B, Levy MA, Kerkhof J, Aref-Eshghi E, Schenkel L, Stuart A, McConkey H, Henneman P, Venema A, Schwartz CE, Stevenson RE, Skinner SA, DuPont BR, Fletcher RS, Balci TB, Siu VM, Granadillo JL, Masters J, Kadour M, Friez MJ, van Haelst MM, Mannens MMAM, Louie RJ, Lee JA, Tedder ML, Alders M. Clinical epigenomics: genome-wide DNA methylation analysis for the diagnosis of Mendelian disorders. Genet Med 2021; 23:1065-1074. [PMID: 33547396 PMCID: PMC8187150 DOI: 10.1038/s41436-020-01096-4] [Citation(s) in RCA: 75] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 12/29/2020] [Accepted: 12/31/2020] [Indexed: 01/23/2023] Open
Abstract
Purpose We describe the clinical implementation of genome-wide DNA methylation analysis in rare disorders across the EpiSign diagnostic laboratory network and the assessment of results and clinical impact in the first subjects tested. Methods We outline the logistics and data flow between an integrated network of clinical diagnostics laboratories in Europe, the United States, and Canada. We describe the clinical validation of EpiSign using 211 specimens and assess the test performance and diagnostic yield in the first 207 subjects tested involving two patient subgroups: the targeted cohort (subjects with previous ambiguous/inconclusive genetic findings including genetic variants of unknown clinical significance) and the screening cohort (subjects with clinical findings consistent with hereditary neurodevelopmental syndromes and no previous conclusive genetic findings). Results Among the 207 subjects tested, 57 (27.6%) were positive for a diagnostic episignature including 48/136 (35.3%) in the targeted cohort and 8/71 (11.3%) in the screening cohort, with 4/207 (1.9%) remaining inconclusive after EpiSign analysis. Conclusion This study describes the implementation of diagnostic clinical genomic DNA methylation testing in patients with rare disorders. It provides strong evidence of clinical utility of EpiSign analysis, including the ability to provide conclusive findings in the majority of subjects tested.
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Affiliation(s)
- Bekim Sadikovic
- Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, ON, Canada. .,Department of Pathology and Laboratory Medicine, Western University, London, ON, Canada.
| | - Michael A Levy
- Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, ON, Canada.,Department of Pathology and Laboratory Medicine, Western University, London, ON, Canada
| | - Jennifer Kerkhof
- Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, ON, Canada.,Department of Pathology and Laboratory Medicine, Western University, London, ON, Canada
| | - Erfan Aref-Eshghi
- Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, ON, Canada.,Department of Pathology and Laboratory Medicine, Western University, London, ON, Canada
| | - Laila Schenkel
- Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, ON, Canada.,Department of Pathology and Laboratory Medicine, Western University, London, ON, Canada
| | - Alan Stuart
- Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, ON, Canada.,Department of Pathology and Laboratory Medicine, Western University, London, ON, Canada
| | - Haley McConkey
- Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, ON, Canada.,Department of Pathology and Laboratory Medicine, Western University, London, ON, Canada
| | - Peter Henneman
- Amsterdam University Medical Center, University of Amsterdam, Department of Clinical Genetics, Amsterdam Reproduction and Development Research Institute, Amsterdam, The Netherlands
| | - Andrea Venema
- Amsterdam University Medical Center, University of Amsterdam, Department of Clinical Genetics, Amsterdam Reproduction and Development Research Institute, Amsterdam, The Netherlands
| | | | | | | | | | | | - Tugce B Balci
- Department of Pediatrics, Division of Medical Genetics, Western University, London, ON, Canada.,Medical Genetics Program of Southwestern Ontario, London Health Sciences Centre, London, ON, Canada
| | - Victoria Mok Siu
- Department of Pediatrics, Division of Medical Genetics, Western University, London, ON, Canada.,Medical Genetics Program of Southwestern Ontario, London Health Sciences Centre, London, ON, Canada
| | - Jorge L Granadillo
- Division of Genetics and Genomic Medicine, Department of Pediatrics, Washington University School of Medicine in St. Louis, St. Louis, MO, USA
| | - Jennefer Masters
- Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, ON, Canada.,Department of Pathology and Laboratory Medicine, Western University, London, ON, Canada
| | - Mike Kadour
- Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, ON, Canada.,Department of Pathology and Laboratory Medicine, Western University, London, ON, Canada
| | | | - Mieke M van Haelst
- Amsterdam University Medical Center, University of Amsterdam, Department of Clinical Genetics, Amsterdam Reproduction and Development Research Institute, Amsterdam, The Netherlands
| | - Marcel M A M Mannens
- Amsterdam University Medical Center, University of Amsterdam, Department of Clinical Genetics, Amsterdam Reproduction and Development Research Institute, Amsterdam, The Netherlands
| | | | | | | | - Marielle Alders
- Amsterdam University Medical Center, University of Amsterdam, Department of Clinical Genetics, Amsterdam Reproduction and Development Research Institute, Amsterdam, The Netherlands.
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9
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Detection of a DNA Methylation Signature for the Intellectual Developmental Disorder, X-Linked, Syndromic, Armfield Type. Int J Mol Sci 2021; 22:ijms22031111. [PMID: 33498634 PMCID: PMC7865843 DOI: 10.3390/ijms22031111] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 01/18/2021] [Accepted: 01/20/2021] [Indexed: 12/19/2022] Open
Abstract
A growing number of genetic neurodevelopmental disorders are known to be associated with unique genomic DNA methylation patterns, called episignatures, which are detectable in peripheral blood. The intellectual developmental disorder, X-linked, syndromic, Armfield type (MRXSA) is caused by missense variants in FAM50A. Functional studies revealed the pathogenesis to be a spliceosomopathy that is characterized by atypical mRNA processing during development. In this study, we assessed the peripheral blood specimens in a cohort of individuals with MRXSA and detected a unique and highly specific DNA methylation episignature associated with this disorder. We used this episignature to construct a support vector machine model capable of sensitive and specific identification of individuals with pathogenic variants in FAM50A. This study contributes to the expanding number of genetic neurodevelopmental disorders with defined DNA methylation episignatures, provides an additional understanding of the associated molecular mechanisms, and further enhances our ability to diagnose patients with rare disorders.
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10
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Schenkel LC, Aref-Eshghi E, Rooney K, Kerkhof J, Levy MA, McConkey H, Rogers RC, Phelan K, Sarasua SM, Jain L, Pauly R, Boccuto L, DuPont B, Cappuccio G, Brunetti-Pierri N, Schwartz CE, Sadikovic B. DNA methylation epi-signature is associated with two molecularly and phenotypically distinct clinical subtypes of Phelan-McDermid syndrome. Clin Epigenetics 2021; 13:2. [PMID: 33407854 PMCID: PMC7789817 DOI: 10.1186/s13148-020-00990-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 12/09/2020] [Indexed: 12/31/2022] Open
Abstract
Background Phelan-McDermid syndrome is characterized by a range of neurodevelopmental phenotypes with incomplete penetrance and variable expressivity. It is caused by a variable size and breakpoint microdeletions in the distal long arm of chromosome 22, referred to as 22q13.3 deletion syndrome, including the SHANK3 gene. Genetic defects in a growing number of neurodevelopmental genes have been shown to cause genome-wide disruptions in epigenomic profiles referred to as epi-signatures in affected individuals. Results In this study we assessed genome-wide DNA methylation profiles in a cohort of 22 individuals with Phelan-McDermid syndrome, including 11 individuals with large (2 to 5.8 Mb) 22q13.3 deletions, 10 with small deletions (< 1 Mb) or intragenic variants in SHANK3 and one mosaic case. We describe a novel genome-wide DNA methylation epi-signature in a subset of individuals with Phelan-McDermid syndrome. Conclusion We identified the critical region including the BRD1 gene as responsible for the Phelan-McDermid syndrome epi-signature. Metabolomic profiles of individuals with the DNA methylation epi-signature showed significantly different metabolomic profiles indicating evidence of two molecularly and phenotypically distinct clinical subtypes of Phelan-McDermid syndrome.
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Affiliation(s)
- L C Schenkel
- Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, ON, N6A5W9, Canada.,Department of Pathology and Laboratory Medicine, Western University, London, ON, N6A3K7, Canada
| | - E Aref-Eshghi
- Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, ON, N6A5W9, Canada
| | - K Rooney
- Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, ON, N6A5W9, Canada
| | - J Kerkhof
- Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, ON, N6A5W9, Canada
| | - M A Levy
- Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, ON, N6A5W9, Canada
| | - H McConkey
- Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, ON, N6A5W9, Canada
| | - R C Rogers
- Greenville Office, Greenwood Genetic Center, Greenville, SC, 29605, USA
| | - K Phelan
- Genetics Laboratory, Florida Cancer Specialists and Research Institute, Fort Myers, FL, 33816, USA
| | | | - L Jain
- Greenwood Genetic Center, Greenwood, SC, 29646, USA.,Clemson University, Clemson, SC, 29634, USA
| | - R Pauly
- Greenwood Genetic Center, Greenwood, SC, 29646, USA
| | - L Boccuto
- Greenwood Genetic Center, Greenwood, SC, 29646, USA.,Clemson University, Clemson, SC, 29634, USA
| | - B DuPont
- Greenwood Genetic Center, Greenwood, SC, 29646, USA
| | - G Cappuccio
- Department of Translational Medicine, University Federico II, 80131, Naples, NA, Italy.,Telethon Institute of Genetics and Medicine, Pozzuoli, NA, Italy
| | - N Brunetti-Pierri
- Department of Translational Medicine, University Federico II, 80131, Naples, NA, Italy.,Telethon Institute of Genetics and Medicine, Pozzuoli, NA, Italy
| | - C E Schwartz
- Greenwood Genetic Center, Greenwood, SC, 29646, USA.
| | - B Sadikovic
- Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, ON, N6A5W9, Canada. .,Department of Pathology and Laboratory Medicine, Western University, London, ON, N6A3K7, Canada.
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11
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Haghshenas S, Bhai P, Aref-Eshghi E, Sadikovic B. Diagnostic Utility of Genome-Wide DNA Methylation Analysis in Mendelian Neurodevelopmental Disorders. Int J Mol Sci 2020; 21:ijms21239303. [PMID: 33291301 PMCID: PMC7730976 DOI: 10.3390/ijms21239303] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2020] [Revised: 12/03/2020] [Accepted: 12/04/2020] [Indexed: 12/14/2022] Open
Abstract
Mendelian neurodevelopmental disorders customarily present with complex and overlapping symptoms, complicating the clinical diagnosis. Individuals with a growing number of the so-called rare disorders exhibit unique, disorder-specific DNA methylation patterns, consequent to the underlying gene defects. Besides providing insights to the pathophysiology and molecular biology of these disorders, we can use these epigenetic patterns as functional biomarkers for the screening and diagnosis of these conditions. This review summarizes our current understanding of DNA methylation episignatures in rare disorders and describes the underlying technology and analytical approaches. We discuss the computational parameters, including statistical and machine learning methods, used for the screening and classification of genetic variants of uncertain clinical significance. Describing the rationale and principles applied to the specific computational models that are used to develop and adapt the DNA methylation episignatures for the diagnosis of rare disorders, we highlight the opportunities and challenges in this emerging branch of diagnostic medicine.
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Affiliation(s)
- Sadegheh Haghshenas
- Department of Pathology and Laboratory Medicine, Western University, London, ON N6A 3K7, Canada;
- Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, ON N6A 5W9, Canada;
| | - Pratibha Bhai
- Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, ON N6A 5W9, Canada;
| | - Erfan Aref-Eshghi
- Division of Genomic Diagnostics, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA;
| | - Bekim Sadikovic
- Department of Pathology and Laboratory Medicine, Western University, London, ON N6A 3K7, Canada;
- Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, ON N6A 5W9, Canada;
- Schulich School of Medicine and Dentistry, Western University, London, ON N6A 5C1, Canada
- Correspondence:
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12
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13
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Aref-Eshghi E, Kerkhof J, Carere DA, Volodarsky M, Bhai P, Colaiacovo S, Saleh M, Caudle M, Karp N, Prasad C, Balci T, Lin H, Campbell C, Siu VM, Sadikovic B. Clinical and technical assessment of MedExome vs. NGS panels in patients with suspected genetic disorders in Southwestern Ontario. J Hum Genet 2020; 66:451-464. [PMID: 33093641 DOI: 10.1038/s10038-020-00860-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/24/2020] [Accepted: 10/05/2020] [Indexed: 11/10/2022]
Abstract
The adaptation of a broad genomic sequencing approach in the clinical setting has been accompanied by considerations regarding the clinical utility, technical performance, and diagnostic yield compared to targeted genetic approaches. We have developed MedExome, an integrated framework for sequencing, variant calling (SNVs, Indels, and CNVs), and clinical assessment of ~4600 medically relevant genes. We compared the technical performance of MedExome with the whole-exome and targeted gene-panel sequencing, assessed the reasons for discordance, and evaluated the added clinical yield of MedExome in a cohort of unresolved subjects suspected of genetic disease. Our analysis showed that despite a higher average read depth in panels (3058 vs. 855), MedExome yielded full coverage of the enriched regions (>20X) and 99% variant concordance rate with panels. The discordance rate was associated with low-complexity regions, high-GC content, and low allele fractions, observed in both platforms. MedExome yielded full sensitivity in detecting clinically actionable variants, and the assessment of 138 patients with suspected genetic conditions resulted in 76 clinical reports (31 full [22.1%], 3 partial, and 42 uncertain/possible molecular diagnoses). MedExome sequencing has comparable performance in variant detection to gene panels. Added diagnostic yield justifies expanded implementation of broad genomic approaches in unresolved patients; however, cost-benefit and health systems impact warrants assessment.
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Affiliation(s)
- Erfan Aref-Eshghi
- Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, ON, Canada
| | - Jennifer Kerkhof
- Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, ON, Canada
| | - Deana Alexis Carere
- Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, ON, Canada
| | - Michael Volodarsky
- Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, ON, Canada
| | - Pratibha Bhai
- Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, ON, Canada
| | - Samantha Colaiacovo
- Medical Genetics Program of Southwestern Ontario, Victoria Hospital, London Health Sciences Centre, London, ON, Canada
| | - Maha Saleh
- Medical Genetics Program of Southwestern Ontario, Victoria Hospital, London Health Sciences Centre, London, ON, Canada
| | - Michelle Caudle
- Medical Genetics Program of Southwestern Ontario, Victoria Hospital, London Health Sciences Centre, London, ON, Canada
| | - Natalya Karp
- Medical Genetics Program of Southwestern Ontario, Victoria Hospital, London Health Sciences Centre, London, ON, Canada
| | - Chitra Prasad
- Medical Genetics Program of Southwestern Ontario, Victoria Hospital, London Health Sciences Centre, London, ON, Canada
| | - Tugce Balci
- Medical Genetics Program of Southwestern Ontario, Victoria Hospital, London Health Sciences Centre, London, ON, Canada
| | - Hanxin Lin
- Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, ON, Canada.,Department of Pathology and Laboratory Medicine, Western University, London, ON, Canada
| | - Craig Campbell
- Department of Pediatric Neurology, Children's Hospital, London Health Science Centre, London, ON, Canada
| | - Victoria Mok Siu
- Medical Genetics Program of Southwestern Ontario, Victoria Hospital, London Health Sciences Centre, London, ON, Canada
| | - Bekim Sadikovic
- Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, ON, Canada. .,Department of Pathology and Laboratory Medicine, Western University, London, ON, Canada.
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14
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Hara-Isono K, Matsubara K, Fuke T, Yamazawa K, Satou K, Murakami N, Saitoh S, Nakabayashi K, Hata K, Ogata T, Fukami M, Kagami M. Genome-wide methylation analysis in Silver-Russell syndrome, Temple syndrome, and Prader-Willi syndrome. Clin Epigenetics 2020; 12:159. [PMID: 33092629 PMCID: PMC7583213 DOI: 10.1186/s13148-020-00949-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 10/13/2020] [Indexed: 12/19/2022] Open
Abstract
Background Imprinting disorders (IDs) show overlapping phenotypes, particularly in Silver–Russell syndrome (SRS), Temple syndrome (TS14), and Prader–Willi syndrome (PWS). These three IDs include fetal and postnatal growth failure, feeding difficulty, and muscular hypotonia as major clinical features. However, the mechanism that causes overlapping phenotypes has not been clarified. To investigate the presence or absence of methylation signatures associated with overlapping phenotypes, we performed genome-wide methylation analysis (GWMA). Results GWMA was carried out on 36 patients with three IDs (SRS [n = 16], TS14 [n = 7], PWS [n = 13]) and 11 child controls using HumanMethylation450 BeadChip including 475,000 CpG sites across the human genome. To reveal an aberrantly methylated region shared by SRS, TS14, and PWS groups, we compared genome-wide methylation data of the three groups with those of control subjects. All the identified regions were known as SRS-, TS14-, and PWS-related imprinting-associated differentially methylated regions (iDMRs), and there was no hypermethylated or hypomethylated region shared by different ID groups. To examine the methylation pattern shared by SRS, TS14, and PWS groups, we performed clustering analysis based on GWMA data. The result focusing on 620 probes at the 62 known iDMRs (except for SRS-, TS14-, and PWS-related iDMRs) classified patients into two categories: (1) category A, grossly normal methylation patterns mainly consisting of SRS group patients; and (2) category B, broad and mild hypermethylation patterns mainly consisting of TS14 and PWS group patients. However, we found no obvious relationship between these methylation patterns and phenotypes of patients. Conclusions GWMA in three IDs found no methylation signatures shared by SRS, TS14, and PWS groups. Although clustering analysis showed similar mild hypermethylation patterns in TS14 and PWS groups, further study is needed to clarify the effect of methylation patterns on the overlapping phenotypes.
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Affiliation(s)
- Kaori Hara-Isono
- Department of Molecular Endocrinology, National Research Institute for Child Health and Development, 2-10-1 Okura, Setagaya-ku, Tokyo, 157-8535, Japan.,Department of Pediatrics, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan
| | - Keiko Matsubara
- Department of Molecular Endocrinology, National Research Institute for Child Health and Development, 2-10-1 Okura, Setagaya-ku, Tokyo, 157-8535, Japan
| | - Tomoko Fuke
- Department of Molecular Endocrinology, National Research Institute for Child Health and Development, 2-10-1 Okura, Setagaya-ku, Tokyo, 157-8535, Japan
| | - Kazuki Yamazawa
- Department of Molecular Endocrinology, National Research Institute for Child Health and Development, 2-10-1 Okura, Setagaya-ku, Tokyo, 157-8535, Japan.,Medical Genetics Center, National Hospital Organization Tokyo Medical Center, 2-5-1 Higashigaoka, Meguro-ku, Tokyo, 152-8902, Japan
| | - Kazuhito Satou
- Department of Genome Medicine, National Research Institute for Child Health and Development, 2-10-1 Okura, Setagaya-ku, Tokyo, 157-8535, Japan
| | - Nobuyuki Murakami
- Department of Pediatrics, Dokkyo Medical University Saitama Medical Center, 2-1-50 Minami Koshigaya, Koshigaya, 343-8555, Japan
| | - Shinji Saitoh
- Department of Pediatrics and Neonatology, Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya, 467-8601, Japan
| | - Kazuhiko Nakabayashi
- Department of Maternal Fetal Biology, National Research Institute for Child Health and Development, 2-10-1 Okura, Setagaya-ku, Tokyo, 157-8535, Japan
| | - Kenichiro Hata
- Department of Maternal Fetal Biology, National Research Institute for Child Health and Development, 2-10-1 Okura, Setagaya-ku, Tokyo, 157-8535, Japan
| | - Tsutomu Ogata
- Department of Molecular Endocrinology, National Research Institute for Child Health and Development, 2-10-1 Okura, Setagaya-ku, Tokyo, 157-8535, Japan.,Department of Pediatrics, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, 431-3192, Japan
| | - Maki Fukami
- Department of Molecular Endocrinology, National Research Institute for Child Health and Development, 2-10-1 Okura, Setagaya-ku, Tokyo, 157-8535, Japan
| | - Masayo Kagami
- Department of Molecular Endocrinology, National Research Institute for Child Health and Development, 2-10-1 Okura, Setagaya-ku, Tokyo, 157-8535, Japan.
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15
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Hartley T, Lemire G, Kernohan KD, Howley HE, Adams DR, Boycott KM. New Diagnostic Approaches for Undiagnosed Rare Genetic Diseases. Annu Rev Genomics Hum Genet 2020; 21:351-372. [DOI: 10.1146/annurev-genom-083118-015345] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Accurate diagnosis is the cornerstone of medicine; it is essential for informed care and promoting patient and family well-being. However, families with a rare genetic disease (RGD) often spend more than five years on a diagnostic odyssey of specialist visits and invasive testing that is lengthy, costly, and often futile, as 50% of patients do not receive a molecular diagnosis. The current diagnostic paradigm is not well designed for RGDs, especially for patients who remain undiagnosed after the initial set of investigations, and thus requires an expansion of approaches in the clinic. Leveraging opportunities to participate in research programs that utilize new technologies to understand RGDs is an important path forward for patients seeking a diagnosis. Given recent advancements in such technologies and international initiatives, the prospect of identifying a molecular diagnosis for all patients with RGDs has never been so attainable, but achieving this goal will require global cooperation at an unprecedented scale.
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Affiliation(s)
- Taila Hartley
- CHEO Research Institute, University of Ottawa, Ottawa, Ontario K1H 8L1, Canada;, , , ,
| | - Gabrielle Lemire
- CHEO Research Institute, University of Ottawa, Ottawa, Ontario K1H 8L1, Canada;, , , ,
- Department of Genetics, CHEO, Ottawa, Ontario K1H 8L1, Canada
| | - Kristin D. Kernohan
- CHEO Research Institute, University of Ottawa, Ottawa, Ontario K1H 8L1, Canada;, , , ,
- Newborn Screening Ontario, CHEO, Ottawa, Ontario K1H 9M8, Canada
| | - Heather E. Howley
- CHEO Research Institute, University of Ottawa, Ottawa, Ontario K1H 8L1, Canada;, , , ,
| | - David R. Adams
- Office of the Clinical Director, National Human Genome Research Institute and Undiagnosed Diseases Program, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Kym M. Boycott
- CHEO Research Institute, University of Ottawa, Ottawa, Ontario K1H 8L1, Canada;, , , ,
- Department of Genetics, CHEO, Ottawa, Ontario K1H 8L1, Canada
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16
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DNA methylation analysis for screening and diagnostic testing in neurodevelopmental disorders. Essays Biochem 2020; 63:785-795. [PMID: 31696914 DOI: 10.1042/ebc20190056] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 10/16/2019] [Accepted: 10/16/2019] [Indexed: 12/12/2022]
Abstract
DNA methylation (mDNA) plays an important role in the pathogenesis of neurodevelopmental disorders (NDDs), however its use in diagnostic testing has been largely restricted to a handful of methods for locus-specific analysis in monogenic syndromes. Recent studies employing genome-wide methylation analysis (GWMA) have explored utility of a single array-based test to detect methylation changes in probands negative by exome sequencing, and to diagnose different monogenic NDDs with defined epigenetic signatures. While this may be a more efficient approach, several significant barriers remain. These include non-uniform and low coverage of regulatory regions that may have CG-rich sequences, and lower analytical sensitivity as compared with locus-specific analyses that may result in methylation mosaicism not being detected. A major challenge associated with the above technologies, regardless of whether the analysis is locus specific or genome wide, is the technical bias introduced by indirect analysis of methylation. This review summarizes evidence from the most recent studies in this field and discusses future directions, including direct analysis of methylation using long-read technologies and detection of 5-methylcytosine (5-mC or total mDNA) and 5-hydroxymethylacytosine (5-hmC) as biomarkers of NDDs.
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17
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Aref-Eshghi E, Biswas S, Chen C, Sadikovic B, Chakrabarti S. Glucose-induced, duration-dependent genome-wide DNA methylation changes in human endothelial cells. Am J Physiol Cell Physiol 2020; 319:C268-C276. [PMID: 32459505 DOI: 10.1152/ajpcell.00011.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
DNA methylation, a critical epigenetic mechanism, plays an important role in governing gene expressions during biological processes such as aging, which is well known to be accelerated in hyperglycemia (diabetes). In the present study, we investigated the effects of glucose on whole genome DNA methylation in small [human retinal microvascular endothelial cells (HRECs)] and large [human umbilical vein endothelial cells (HUVECs)] vessel endothelial cell (EC) lines exposed to basal or high glucose-containing media for variable lengths of time. Using the Infinium EPIC array, we obtained 773,133 CpG sites (probes) for analysis. Unsupervised clustering of the top 5% probes identified four distinct clusters within EC groups, with significant methylation differences attributed to EC types and the duration of cell culture rather than glucose stimuli alone. When comparing the ECs incubated for 2 days versus 7 days, hierarchical clustering analyses [methylation change >10% and false discovery rate (FDR) <0.05] identified 17,354 and 128 differentially methylated CpGs for HUVECs and HRECs, respectively. Predominant DNA hypermethylation was associated with the length of culture and was enriched for gene enhancer elements and regions surrounding CpG shores and shelves. We identified 88 differentially methylated regions (DMRs) for HUVECs and 8 DMRs for HRECs (all FDR <0.05). Pathway enrichment analyses of DMRs highlighted involvement of regulators of embryonic development (i.e., HOX genes) and cellular differentiation [transforming growth factor-β (TGF-β) family members]. Collectively, our findings suggest that DNA methylation is a complex process that involves tightly coordinated, cell-specific mechanisms. Such changes in methylation overlap genes critical for cellular differentiation and embryonic development.
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Affiliation(s)
- Erfan Aref-Eshghi
- Department of Pathology and Laboratory Medicine, London Health Sciences Centre, London, Ontario, Canada
| | - Saumik Biswas
- Department of Pathology and Laboratory Medicine, Western University, London, Ontario, Canada
| | - Charlie Chen
- Department of Pathology and Laboratory Medicine, Western University, London, Ontario, Canada
| | - Bekim Sadikovic
- Department of Pathology and Laboratory Medicine, London Health Sciences Centre, London, Ontario, Canada.,Department of Pathology and Laboratory Medicine, Western University, London, Ontario, Canada
| | - Subrata Chakrabarti
- Department of Pathology and Laboratory Medicine, London Health Sciences Centre, London, Ontario, Canada.,Department of Pathology and Laboratory Medicine, Western University, London, Ontario, Canada
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18
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DNA Methylation in the Diagnosis of Monogenic Diseases. Genes (Basel) 2020; 11:genes11040355. [PMID: 32224912 PMCID: PMC7231024 DOI: 10.3390/genes11040355] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 03/13/2020] [Accepted: 03/24/2020] [Indexed: 02/08/2023] Open
Abstract
DNA methylation in the human genome is largely programmed and shaped by transcription factor binding and interaction between DNA methyltransferases and histone marks during gamete and embryo development. Normal methylation profiles can be modified at single or multiple loci, more frequently as consequences of genetic variants acting in cis or in trans, or in some cases stochastically or through interaction with environmental factors. For many developmental disorders, specific methylation patterns or signatures can be detected in blood DNA. The recent use of high-throughput assays investigating the whole genome has largely increased the number of diseases for which DNA methylation analysis provides information for their diagnosis. Here, we review the methylation abnormalities that have been associated with mono/oligogenic diseases, their relationship with genotype and phenotype and relevance for diagnosis, as well as the limitations in their use and interpretation of results.
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19
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Aref-Eshghi E, Kerkhof J, Pedro VP, Barat-Houari M, Ruiz-Pallares N, Andrau JC, Lacombe D, Van-Gils J, Fergelot P, Dubourg C, Cormier-Daire V, Rondeau S, Lecoquierre F, Saugier-Veber P, Nicolas G, Lesca G, Chatron N, Sanlaville D, Vitobello A, Faivre L, Thauvin-Robinet C, Laumonnier F, Raynaud M, Alders M, Mannens M, Henneman P, Hennekam RC, Velasco G, Francastel C, Ulveling D, Ciolfi A, Pizzi S, Tartaglia M, Heide S, Héron D, Mignot C, Keren B, Whalen S, Afenjar A, Bienvenu T, Campeau PM, Rousseau J, Levy MA, Brick L, Kozenko M, Balci TB, Siu VM, Stuart A, Kadour M, Masters J, Takano K, Kleefstra T, de Leeuw N, Field M, Shaw M, Gecz J, Ainsworth PJ, Lin H, Rodenhiser DI, Friez MJ, Tedder M, Lee JA, DuPont BR, Stevenson RE, Skinner SA, Schwartz CE, Genevieve D, Sadikovic B, Sadikovic B. Evaluation of DNA Methylation Episignatures for Diagnosis and Phenotype Correlations in 42 Mendelian Neurodevelopmental Disorders. Am J Hum Genet 2020; 106:356-370. [PMID: 32109418 DOI: 10.1016/j.ajhg.2020.01.019] [Citation(s) in RCA: 149] [Impact Index Per Article: 37.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 01/27/2020] [Indexed: 01/24/2023] Open
Abstract
Genetic syndromes frequently present with overlapping clinical features and inconclusive or ambiguous genetic findings which can confound accurate diagnosis and clinical management. An expanding number of genetic syndromes have been shown to have unique genomic DNA methylation patterns (called "episignatures"). Peripheral blood episignatures can be used for diagnostic testing as well as for the interpretation of ambiguous genetic test results. We present here an approach to episignature mapping in 42 genetic syndromes, which has allowed the identification of 34 robust disease-specific episignatures. We examine emerging patterns of overlap, as well as similarities and hierarchical relationships across these episignatures, to highlight their key features as they are related to genetic heterogeneity, dosage effect, unaffected carrier status, and incomplete penetrance. We demonstrate the necessity of multiclass modeling for accurate genetic variant classification and show how disease classification using a single episignature at a time can sometimes lead to classification errors in closely related episignatures. We demonstrate the utility of this tool in resolving ambiguous clinical cases and identification of previously undiagnosed cases through mass screening of a large cohort of subjects with developmental delays and congenital anomalies. This study more than doubles the number of published syndromes with DNA methylation episignatures and, most significantly, opens new avenues for accurate diagnosis and clinical assessment in individuals affected by these disorders.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Bekim Sadikovic
- Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, ON N6A5W9, Canada; Department of Pathology and Laboratory Medicine, Western University, London, ON N6A3K7, Canada.
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20
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Ciolfi A, Aref-Eshghi E, Pizzi S, Pedace L, Miele E, Kerkhof J, Flex E, Martinelli S, Radio FC, Ruivenkamp CAL, Santen GWE, Bijlsma E, Barge-Schaapveld D, Ounap K, Siu VM, Kooy RF, Dallapiccola B, Sadikovic B, Tartaglia M. Frameshift mutations at the C-terminus of HIST1H1E result in a specific DNA hypomethylation signature. Clin Epigenetics 2020; 12:7. [PMID: 31910894 PMCID: PMC6947958 DOI: 10.1186/s13148-019-0804-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 12/26/2019] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND We previously associated HIST1H1E mutations causing Rahman syndrome with a specific genome-wide methylation pattern. RESULTS Methylome analysis from peripheral blood samples of six affected subjects led us to identify a specific hypomethylated profile. This "episignature" was enriched for genes involved in neuronal system development and function. A computational classifier yielded full sensitivity and specificity in detecting subjects with Rahman syndrome. Applying this model to a cohort of undiagnosed probands allowed us to reach diagnosis in one subject. CONCLUSIONS We demonstrate an epigenetic signature in subjects with Rahman syndrome that can be used to reach molecular diagnosis.
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Affiliation(s)
- Andrea Ciolfi
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, IRCCS, 00146, Rome, Italy
| | - Erfan Aref-Eshghi
- Department of Pathology and Laboratory Medicine, Western University, London, N6A 5C1, Canada.,Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, N6A 5W9, Canada
| | - Simone Pizzi
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, IRCCS, 00146, Rome, Italy
| | - Lucia Pedace
- Department of Pediatric Onco-Hematology and Cell and Gene Therapy, Ospedale Pediatrico Bambino Gesù, IRCCS, 00146, Rome, Italy
| | - Evelina Miele
- Department of Pediatric Onco-Hematology and Cell and Gene Therapy, Ospedale Pediatrico Bambino Gesù, IRCCS, 00146, Rome, Italy
| | - Jennifer Kerkhof
- Department of Pathology and Laboratory Medicine, Western University, London, N6A 5C1, Canada.,Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, N6A 5W9, Canada
| | - Elisabetta Flex
- Department of Oncology and Molecular Medicine, Istituto Superiore di Sanità, 00161, Rome, Italy
| | - Simone Martinelli
- Department of Oncology and Molecular Medicine, Istituto Superiore di Sanità, 00161, Rome, Italy
| | - Francesca Clementina Radio
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, IRCCS, 00146, Rome, Italy
| | - Claudia A L Ruivenkamp
- Department of Clinical Genetics, Leiden University Medical Center, Leiden, 2300, The Netherlands
| | - Gijs W E Santen
- Department of Clinical Genetics, Leiden University Medical Center, Leiden, 2300, The Netherlands
| | - Emilia Bijlsma
- Department of Clinical Genetics, Leiden University Medical Center, Leiden, 2300, The Netherlands
| | - Daniela Barge-Schaapveld
- Department of Clinical Genetics, Leiden University Medical Center, Leiden, 2300, The Netherlands
| | - Katrin Ounap
- Department of Clinical Genetics, United Laboratories, Tartu University Hospital, 50406, Tartu, Estonia.,Institute of Clinical Medicine, University of Tartu, 50406, Tartu, Estonia
| | - Victoria Mok Siu
- Medical Genetics Program of Southwestern Ontario, London Health Sciences Centre, London, ON, N6A 5W9, Canada
| | - R Frank Kooy
- Department of Medical Genetics, University of Antwerp, 2650, Antwerp, Belgium
| | - Bruno Dallapiccola
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, IRCCS, 00146, Rome, Italy
| | - Bekim Sadikovic
- Department of Pathology and Laboratory Medicine, Western University, London, N6A 5C1, Canada. .,Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, N6A 5W9, Canada.
| | - Marco Tartaglia
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, IRCCS, 00146, Rome, Italy.
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21
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Bellanti JA. Epigenetic studies and pediatric research. Pediatr Res 2020; 87:378-384. [PMID: 31731288 DOI: 10.1038/s41390-019-0644-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Revised: 10/04/2019] [Accepted: 10/21/2019] [Indexed: 02/08/2023]
Abstract
The 2020 Annual Review Issue, "Preventing Disease in the 21st Century" was selected by the Editors-in-Chief of Pediatric Research to include a variety of disease entities that confront health-care practitioners entrusted to the care of infants and children. In keeping with this mandate, this article reviews the subject of epigenetics, which impacts pediatric research from bench to bedside. Epigenetic mechanisms exert their effects through the interaction of environment, various susceptibility genes, and immunologic development and include: (1) DNA methylation; (2) posttranslational modifications of histone proteins through acetylation and methylation, and (3) RNA-mediated gene silencing by microRNA (miRNA) regulation. The effects of epigenetics during fetal life and early periods of development are first reviewed together with clinical applications of cardiovascular and metabolic disorders in later life. The relationships of epigenetics to the allergic and autoimmune diseases and cancer are next reviewed. A specific focus of the article is directed to the recent recognition that many of these disorders are driven by aberrant immune responses in which immunoregulatory events are often poorly functioning and where through interventive epigenetic measures prevention may be possible by alterations in programming of DNA during fetal and early periods as well as in later life.
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Affiliation(s)
- Joseph A Bellanti
- Departments of Pediatrics and Microbiology-Immunology, Georgetown University Medical Center, Washington, DC, USA. .,International Center for Interdisciplinary Studies of Immunology (ICISI), Georgetown University Medical Center, Washington, DC, USA.
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22
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Aref-Eshghi E, Bourque DK, Kerkhof J, Carere DA, Ainsworth P, Sadikovic B, Armour CM, Lin H. Genome-wide DNA methylation and RNA analyses enable reclassification of two variants of uncertain significance in a patient with clinical Kabuki syndrome. Hum Mutat 2019; 40:1684-1689. [PMID: 31268616 DOI: 10.1002/humu.23833] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 05/14/2019] [Accepted: 05/31/2019] [Indexed: 12/13/2022]
Abstract
Nontruncating sequence variants represent a major challenge in variant interpretation and classification. Here, we report a patient with features of Kabuki syndrome who carries two rare heterozygous variants in KMT2D: c.12935C>T, p.(Ser4312Phe) and c.15785-10T>G. The clinical significance of these variants were discordantly interpreted by different diagnostic laboratories. Parental testing showed that the missense variant was inherited from the father with a mild Kabuki phenotype and the intronic variant from the mother with mosaic status. Through genome-wide DNA methylation analysis of peripheral blood, we confirmed that the proband exhibited a previously described episignature of Kabuki syndrome. Parental samples had normal DNA methylation profiles, thus ruling out the involvement of the paternally inherited missense variant. RNA analysis revealed that the intronic change resulted in exon 49 skipping and frameshift, thereby providing a molecular diagnosis of Kabuki syndrome. This study demonstrates the utility of epigenomic and RNA analyses in resolving ambiguous clinical cases.
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Affiliation(s)
- Erfan Aref-Eshghi
- Department of Pathology and Laboratory Medicine, Western University, London, Ontario, Canada.,Molecular Genetics Laboratory, Division of Molecular Diagnostics, Department of Pathology and Laboratory Medicine, London Health Sciences Centre, London, Ontario, Canada
| | - Danielle K Bourque
- Regional Genetics Unit, Children's Hospital of Eastern Ontario, Ottawa, Ontario, Canada
| | - Jennifer Kerkhof
- Molecular Genetics Laboratory, Division of Molecular Diagnostics, Department of Pathology and Laboratory Medicine, London Health Sciences Centre, London, Ontario, Canada
| | - Deanna Alexis Carere
- Molecular Genetics Laboratory, Division of Molecular Diagnostics, Department of Pathology and Laboratory Medicine, London Health Sciences Centre, London, Ontario, Canada
| | - Peter Ainsworth
- Department of Pathology and Laboratory Medicine, Western University, London, Ontario, Canada.,Molecular Genetics Laboratory, Division of Molecular Diagnostics, Department of Pathology and Laboratory Medicine, London Health Sciences Centre, London, Ontario, Canada
| | - Bekim Sadikovic
- Department of Pathology and Laboratory Medicine, Western University, London, Ontario, Canada.,Molecular Genetics Laboratory, Division of Molecular Diagnostics, Department of Pathology and Laboratory Medicine, London Health Sciences Centre, London, Ontario, Canada
| | - Christine M Armour
- Regional Genetics Unit, Children's Hospital of Eastern Ontario, Ottawa, Ontario, Canada.,Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Ontario, Canada
| | - Hanxin Lin
- Department of Pathology and Laboratory Medicine, Western University, London, Ontario, Canada.,Molecular Genetics Laboratory, Division of Molecular Diagnostics, Department of Pathology and Laboratory Medicine, London Health Sciences Centre, London, Ontario, Canada
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23
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Garg P, Sharp AJ. Screening for rare epigenetic variations in autism and schizophrenia. Hum Mutat 2019; 40:952-961. [PMID: 30900359 PMCID: PMC6801017 DOI: 10.1002/humu.23740] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 02/19/2019] [Accepted: 03/06/2019] [Indexed: 01/28/2023]
Abstract
While many studies have led to the identification of rare sequence variants linked with susceptibility to autism and schizophrenia, the contribution of rare epigenetic variations (epivariations) in these disorders remains largely unexplored. Previously we presented evidence that epivariations occur relatively frequently in the human genome, and likely contribute to a subset of congenital and neurodevelopmental disorders through the disruption of dosage-sensitive genes. Here we extend this approach, studying methylation profiles from 297 samples with autism and 767 cases with schizophrenia, identifying 84 and 268 rare epivariations in these two cohorts, respectively, that were absent from 4,860 population controls. We observed multiple features associated with these epivariations that support their pathogenic relevance, including (a) a significant enrichment for epivariations in schizophrenic individuals at genes previously linked with schizophrenia, (b) increased brain expression of genes associated with epivariations found in autism cases compared with controls, (c) in autism families, a significant excess of epivariations found specifically in affected versus unaffected sibs, (d) Gene Ontology terms linked with epivariations found in autism, including "D1 dopamine receptor binding." Our study provides additional evidence that rare epivariations likely contribute to the mutational spectra underlying neurodevelopmental disorders.
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Affiliation(s)
- Paras Garg
- Department of Genetics and Genomic Sciences, Mount Sinai School of Medicine, Hess Center for Science and Medicine, New York, New York
| | - Andrew J. Sharp
- Department of Genetics and Genomic Sciences, Mount Sinai School of Medicine, Hess Center for Science and Medicine, New York, New York
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24
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Bend EG, Aref-Eshghi E, Everman DB, Rogers RC, Cathey SS, Prijoles EJ, Lyons MJ, Davis H, Clarkson K, Gripp KW, Li D, Bhoj E, Zackai E, Mark P, Hakonarson H, Demmer LA, Levy MA, Kerkhof J, Stuart A, Rodenhiser D, Friez MJ, Stevenson RE, Schwartz CE, Sadikovic B. Gene domain-specific DNA methylation episignatures highlight distinct molecular entities of ADNP syndrome. Clin Epigenetics 2019; 11:64. [PMID: 31029150 PMCID: PMC6487024 DOI: 10.1186/s13148-019-0658-5] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 03/27/2019] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND ADNP syndrome is a rare Mendelian disorder characterized by global developmental delay, intellectual disability, and autism. It is caused by truncating mutations in ADNP, which is involved in chromatin regulation. We hypothesized that the disruption of chromatin regulation might result in specific DNA methylation patterns that could be used in the molecular diagnosis of ADNP syndrome. RESULTS We identified two distinct and partially opposing genomic DNA methylation episignatures in the peripheral blood samples from 22 patients with ADNP syndrome. The "epi-ADNP-1" episignature included ~ 6000 mostly hypomethylated CpGs, and the "epi-ADNP-2" episignature included ~ 1000 predominantly hypermethylated CpGs. The two signatures correlated with the locations of the ADNP mutations. Epi-ADNP-1 mutations occupy the N- and C-terminus, and epi-ADNP-2 mutations are centered on the nuclear localization signal. The episignatures were enriched for genes involved in neuronal system development and function. A classifier trained on these profiles yielded full sensitivity and specificity in detecting patients with either of the two episignatures. Applying this model to seven patients with uncertain clinical diagnosis enabled reclassification of genetic variants of uncertain significance and assigned new diagnosis when the primary clinical suspicion was not correct. When applied to a large cohort of unresolved patients with developmental delay (N = 1150), the model predicted three additional previously undiagnosed patients to have ADNP syndrome. DNA sequencing of these subjects, wherever available, identified pathogenic mutations within the gene domains predicted by the model. CONCLUSIONS We describe the first Mendelian condition with two distinct episignatures caused by mutations in a single gene. These highly sensitive and specific DNA methylation episignatures enable diagnosis, screening, and genetic variant classifications in ADNP syndrome.
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Affiliation(s)
- Eric G. Bend
- Greenwood Genetic Center, 106 Gregor Mendel Cir, Greenwood, SC 29646 USA
- PreventionGenetics, Marshfield, WI USA
| | - Erfan Aref-Eshghi
- Department of Pathology and Laboratory Medicine, Western University, 800 Commissioner’s Road E, London, ON N6A 5W9 Canada
- Molecular Genetics Laboratory, Victoria Hospital, London Health Sciences Centre, London, ON Canada
| | - David B. Everman
- Greenwood Genetic Center, 106 Gregor Mendel Cir, Greenwood, SC 29646 USA
| | - R. Curtis Rogers
- Greenwood Genetic Center, 106 Gregor Mendel Cir, Greenwood, SC 29646 USA
| | - Sara S. Cathey
- Greenwood Genetic Center, 106 Gregor Mendel Cir, Greenwood, SC 29646 USA
| | - Eloise J. Prijoles
- Greenwood Genetic Center, 106 Gregor Mendel Cir, Greenwood, SC 29646 USA
| | - Michael J. Lyons
- Greenwood Genetic Center, 106 Gregor Mendel Cir, Greenwood, SC 29646 USA
| | - Heather Davis
- Greenwood Genetic Center, 106 Gregor Mendel Cir, Greenwood, SC 29646 USA
| | - Katie Clarkson
- Greenwood Genetic Center, 106 Gregor Mendel Cir, Greenwood, SC 29646 USA
| | | | - Dong Li
- Center for Applied Genomics, Children’s Hospital of Philadelphia, Philadelphia, PA USA
| | - Elizabeth Bhoj
- Center for Applied Genomics, Children’s Hospital of Philadelphia, Philadelphia, PA USA
| | - Elaine Zackai
- Division of Human Genetics, Children’s Hospital of Philadelphia, Philadelphia, PA USA
| | - Paul Mark
- Spectrum Health, Grand Rapids, MI USA
| | - Hakon Hakonarson
- Center for Applied Genomics, Children’s Hospital of Philadelphia, Philadelphia, PA USA
| | - Laurie A. Demmer
- Levine Children’s Hospital, Carolinas Medical Center, Charlotte, NC USA
| | - Michael A. Levy
- Department of Pathology and Laboratory Medicine, Western University, 800 Commissioner’s Road E, London, ON N6A 5W9 Canada
- Molecular Genetics Laboratory, Victoria Hospital, London Health Sciences Centre, London, ON Canada
| | - Jennifer Kerkhof
- Department of Pathology and Laboratory Medicine, Western University, 800 Commissioner’s Road E, London, ON N6A 5W9 Canada
- Molecular Genetics Laboratory, Victoria Hospital, London Health Sciences Centre, London, ON Canada
| | - Alan Stuart
- Department of Pathology and Laboratory Medicine, Western University, 800 Commissioner’s Road E, London, ON N6A 5W9 Canada
- Molecular Genetics Laboratory, Victoria Hospital, London Health Sciences Centre, London, ON Canada
| | - David Rodenhiser
- Department of Pediatrics, Biochemistry and Oncology, Western University, London, ON Canada
| | - Michael J. Friez
- Greenwood Genetic Center, 106 Gregor Mendel Cir, Greenwood, SC 29646 USA
| | - Roger E. Stevenson
- Greenwood Genetic Center, 106 Gregor Mendel Cir, Greenwood, SC 29646 USA
| | | | - Bekim Sadikovic
- Department of Pathology and Laboratory Medicine, Western University, 800 Commissioner’s Road E, London, ON N6A 5W9 Canada
- Molecular Genetics Laboratory, Victoria Hospital, London Health Sciences Centre, London, ON Canada
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25
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Aref-Eshghi E, Bend EG, Colaiacovo S, Caudle M, Chakrabarti R, Napier M, Brick L, Brady L, Carere DA, Levy MA, Kerkhof J, Stuart A, Saleh M, Beaudet AL, Li C, Kozenko M, Karp N, Prasad C, Siu VM, Tarnopolsky MA, Ainsworth PJ, Lin H, Rodenhiser DI, Krantz ID, Deardorff MA, Schwartz CE, Sadikovic B. Diagnostic Utility of Genome-wide DNA Methylation Testing in Genetically Unsolved Individuals with Suspected Hereditary Conditions. Am J Hum Genet 2019; 104:685-700. [PMID: 30929737 DOI: 10.1016/j.ajhg.2019.03.008] [Citation(s) in RCA: 107] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 03/05/2019] [Indexed: 12/13/2022] Open
Abstract
Conventional genetic testing of individuals with neurodevelopmental presentations and congenital anomalies (ND/CAs), i.e., the analysis of sequence and copy number variants, leaves a substantial proportion of them unexplained. Some of these cases have been shown to result from DNA methylation defects at a single locus (epi-variants), while others can exhibit syndrome-specific DNA methylation changes across multiple loci (epi-signatures). Here, we investigate the clinical diagnostic utility of genome-wide DNA methylation analysis of peripheral blood in unresolved ND/CAs. We generate a computational model enabling concurrent detection of 14 syndromes using DNA methylation data with full accuracy. We demonstrate the ability of this model in resolving 67 individuals with uncertain clinical diagnoses, some of whom had variants of unknown clinical significance (VUS) in the related genes. We show that the provisional diagnoses can be ruled out in many of the case subjects, some of whom are shown by our model to have other diseases initially not considered. By applying this model to a cohort of 965 ND/CA-affected subjects without a previous diagnostic assumption and a separate assessment of rare epi-variants in this cohort, we identify 15 case subjects with syndromic Mendelian disorders, 12 case subjects with imprinting and trinucleotide repeat expansion disorders, as well as 106 case subjects with rare epi-variants, a portion of which involved genes clinically or functionally linked to the subjects' phenotypes. This study demonstrates that genomic DNA methylation analysis can facilitate the molecular diagnosis of unresolved clinical cases and highlights the potential value of epigenomic testing in the routine clinical assessment of ND/CAs.
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26
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Sadikovic B, Aref-Eshghi E, Levy MA, Rodenhiser D. DNA methylation signatures in mendelian developmental disorders as a diagnostic bridge between genotype and phenotype. Epigenomics 2019; 11:563-575. [PMID: 30875234 DOI: 10.2217/epi-2018-0192] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Epigenetic and genetic mechanisms regulate the establishment and maintenance of gene expression in its proper context. Recent genome-wide mapping approaches have identified DNA methylation (DNAm) signatures in patients clinically diagnosed with syndromes manifesting as developmental disabilities with intellectual impairments. Here, we review recent studies in which these DNA methylation signatures have enabled highly sensitive and specific screening of such individuals and have clarified ambiguous cases where subjects present with genetic sequence variants of unknown clinical significance (VUS). We propose that these episignatures be considered as echoes and/or legacies of the initiating mutational events within proteins of the so-called epigenetic machinery. As well, we discuss approaches to directly confirm the functional consequences and the implications of these episignatures to patient management and treatment.
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Affiliation(s)
- Bekim Sadikovic
- Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, ON, N6A 5W9, Canada.,Department of Pathology & Laboratory Medicine, Western University, London, ON, N6A 3K7, Canada
| | - Erfan Aref-Eshghi
- Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, ON, N6A 5W9, Canada.,Department of Pathology & Laboratory Medicine, Western University, London, ON, N6A 3K7, Canada
| | - Michael A Levy
- Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, ON, N6A 5W9, Canada.,Department of Pathology & Laboratory Medicine, Western University, London, ON, N6A 3K7, Canada
| | - David Rodenhiser
- Departments of Pediatrics, Biochemistry & Oncology, Western University, London, ON, N6A 3K7, Canada.,Children's Health Research Institute & Lawson Health Research Institute, London, ON, N6C 2V5, Canada.,London Regional Cancer Program, Lawson Health Research Institute, London, ON, N6A 5W9, Canada
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27
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Aref-Eshghi E, Bend EG, Hood RL, Schenkel LC, Carere DA, Chakrabarti R, Nagamani SCS, Cheung SW, Campeau PM, Prasad C, Siu VM, Brady L, Tarnopolsky MA, Callen DJ, Innes AM, White SM, Meschino WS, Shuen AY, Paré G, Bulman DE, Ainsworth PJ, Lin H, Rodenhiser DI, Hennekam RC, Boycott KM, Schwartz CE, Sadikovic B. BAFopathies' DNA methylation epi-signatures demonstrate diagnostic utility and functional continuum of Coffin-Siris and Nicolaides-Baraitser syndromes. Nat Commun 2018; 9:4885. [PMID: 30459321 PMCID: PMC6244416 DOI: 10.1038/s41467-018-07193-y] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 10/18/2018] [Indexed: 01/16/2023] Open
Abstract
Coffin–Siris and Nicolaides–Baraitser syndromes (CSS and NCBRS) are Mendelian disorders caused by mutations in subunits of the BAF chromatin remodeling complex. We report overlapping peripheral blood DNA methylation epi-signatures in individuals with various subtypes of CSS (ARID1B, SMARCB1, and SMARCA4) and NCBRS (SMARCA2). We demonstrate that the degree of similarity in the epi-signatures of some CSS subtypes and NCBRS can be greater than that within CSS, indicating a link in the functional basis of the two syndromes. We show that chromosome 6q25 microdeletion syndrome, harboring ARID1B deletions, exhibits a similar CSS/NCBRS methylation profile. Specificity of this epi-signature was confirmed across a wide range of neurodevelopmental conditions including other chromatin remodeling and epigenetic machinery disorders. We demonstrate that a machine-learning model trained on this DNA methylation profile can resolve ambiguous clinical cases, reclassify those with variants of unknown significance, and identify previously undiagnosed subjects through targeted population screening. Mutations in genes encoding subunits of the BAF complex can cause Coffin–Siris and Nicolaides–Baraitser syndromes. Here the authors identify overlapping DNA methylation signatures in individuals with subtypes of these two syndromes that suggest a functional link and can be used to diagnose subjects with unclear clinical presentations.
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Affiliation(s)
- Erfan Aref-Eshghi
- Department of Pathology and Laboratory Medicine, Western University, London, N6A 5W9, ON, Canada.,Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, N6A 5W9, ON, Canada
| | - Eric G Bend
- Prevention Genetics, Marshfield, 54449, WI, USA
| | - Rebecca L Hood
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, K1H 8L1, ON, Canada
| | - Laila C Schenkel
- Department of Pathology and Laboratory Medicine, Western University, London, N6A 5W9, ON, Canada.,Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, N6A 5W9, ON, Canada
| | - Deanna Alexis Carere
- Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, N6A 5W9, ON, Canada
| | - Rana Chakrabarti
- Children's Health Research Institute, London, N6A 5W9, ON, Canada
| | - Sandesh C S Nagamani
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, 77030, TX, USA
| | - Sau Wai Cheung
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, 77030, TX, USA
| | - Philippe M Campeau
- Department of Pediatrics, University of Montreal, Montreal, H3C 3J7, QC, Canada
| | - Chitra Prasad
- Children's Health Research Institute, London, N6A 5W9, ON, Canada
| | - Victoria Mok Siu
- Children's Health Research Institute, London, N6A 5W9, ON, Canada
| | - Lauren Brady
- Department of Pediatrics, McMaster University, Hamilton, L8P 1A2, ON, Canada
| | - Mark A Tarnopolsky
- Department of Pediatrics, McMaster University, Hamilton, L8P 1A2, ON, Canada
| | - David J Callen
- Department of Pediatrics, McMaster University, Hamilton, L8P 1A2, ON, Canada
| | - A Micheil Innes
- Department of Medical Genetics, Alberta Children's Hospital Research Institute for Child and Maternal Health, University of Calgary, Calgary, T3B 6A8, AB, Canada
| | - Susan M White
- Department of Paediatrics, University of Melbourne, Melbourne, 3052, VIC, Australia
| | - Wendy S Meschino
- Genetics Program, North York General Hospital, Toronto, M2K 1E1, ON, Canada
| | - Andrew Y Shuen
- Children's Health Research Institute, London, N6A 5W9, ON, Canada
| | - Guillaume Paré
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, L8P 1A2, ON, Canada
| | - Dennis E Bulman
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, K1H 8L1, ON, Canada
| | - Peter J Ainsworth
- Department of Pathology and Laboratory Medicine, Western University, London, N6A 5W9, ON, Canada.,Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, N6A 5W9, ON, Canada
| | - Hanxin Lin
- Department of Pathology and Laboratory Medicine, Western University, London, N6A 5W9, ON, Canada.,Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, N6A 5W9, ON, Canada
| | - David I Rodenhiser
- Children's Health Research Institute, London, N6A 5W9, ON, Canada.,Department of Pediatrics, Biochemistry and Oncology, Western University, London, N6A 5W9, ON, Canada
| | - Raoul C Hennekam
- Department of Pediatrics, Academic Medical Center, University of Amsterdam, Amsterdam, 1012 WX, The Netherlands
| | - Kym M Boycott
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, K1H 8L1, ON, Canada
| | | | - Bekim Sadikovic
- Department of Pathology and Laboratory Medicine, Western University, London, N6A 5W9, ON, Canada. .,Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, N6A 5W9, ON, Canada.
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28
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Identification of rare de novo epigenetic variations in congenital disorders. Nat Commun 2018; 9:2064. [PMID: 29802345 PMCID: PMC5970273 DOI: 10.1038/s41467-018-04540-x] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 05/08/2018] [Indexed: 01/05/2023] Open
Abstract
Certain human traits such as neurodevelopmental disorders (NDs) and congenital anomalies (CAs) are believed to be primarily genetic in origin. However, even after whole-genome sequencing (WGS), a substantial fraction of such disorders remain unexplained. We hypothesize that some cases of ND-CA are caused by aberrant DNA methylation leading to dysregulated genome function. Comparing DNA methylation profiles from 489 individuals with ND-CAs against 1534 controls, we identify epivariations as a frequent occurrence in the human genome. De novo epivariations are significantly enriched in cases, while RNAseq analysis shows that epivariations often have an impact on gene expression comparable to loss-of-function mutations. Additionally, we detect and replicate an enrichment of rare sequence mutations overlapping CTCF binding sites close to epivariations, providing a rationale for interpreting non-coding variation. We propose that epivariations contribute to the pathogenesis of some patients with unexplained ND-CAs, and as such likely have diagnostic relevance.
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29
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Schenkel LC, Aref-Eshghi E, Skinner C, Ainsworth P, Lin H, Paré G, Rodenhiser DI, Schwartz C, Sadikovic B. Peripheral blood epi-signature of Claes-Jensen syndrome enables sensitive and specific identification of patients and healthy carriers with pathogenic mutations in KDM5C. Clin Epigenetics 2018; 10:21. [PMID: 29456765 PMCID: PMC5813334 DOI: 10.1186/s13148-018-0453-8] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 02/02/2018] [Indexed: 12/02/2022] Open
Abstract
Background Claes-Jensen syndrome is an X-linked inherited intellectual disability caused by mutations in the KDM5C gene. Kdm5c is a histone lysine demethylase involved in histone modifications and chromatin remodeling. Males with hemizygous mutations in KDM5C present with intellectual disability and facial dysmorphism, while most heterozygous female carriers are asymptomatic. We hypothesized that loss of Kdm5c function may influence other components of the epigenomic machinery including DNA methylation in affected patients. Results Genome-wide DNA methylation analysis of 7 male patients affected with Claes-Jensen syndrome and 56 age- and sex-matched controls identified a specific DNA methylation defect (epi-signature) in the peripheral blood of these patients, including 1769 individual CpGs and 9 genomic regions. Six healthy female carriers showed less pronounced but distinctive changes in the same regions enabling their differentiation from both patients and controls. Highly specific computational model using the most significant methylation changes demonstrated 100% accuracy in differentiating patients, carriers, and controls in the training cohort, which was confirmed on a separate cohort of patients and carriers. The 100% specificity of this unique epi-signature was further confirmed on additional 500 unaffected controls and 600 patients with intellectual disability and developmental delay, including other patient cohorts with previously described epi-signatures. Conclusion Peripheral blood epi-signature in Claes-Jensen syndrome can be used for molecular diagnosis and carrier identification and assist with interpretation of genetic variants of unknown clinical significance in the KDM5C gene. Electronic supplementary material The online version of this article (10.1186/s13148-018-0453-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Laila C Schenkel
- 1Department of Pathology and Laboratory Medicine, Western University, London, Ontario Canada.,2Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, Ontario Canada
| | - Erfan Aref-Eshghi
- 1Department of Pathology and Laboratory Medicine, Western University, London, Ontario Canada.,2Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, Ontario Canada
| | | | - Peter Ainsworth
- 1Department of Pathology and Laboratory Medicine, Western University, London, Ontario Canada.,2Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, Ontario Canada
| | - Hanxin Lin
- 1Department of Pathology and Laboratory Medicine, Western University, London, Ontario Canada.,2Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, Ontario Canada
| | - Guillaume Paré
- 4Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario Canada
| | - David I Rodenhiser
- 5Departments of Pediatrics, Biochemistry and Oncology, Western University, London, Ontario Canada
| | | | - Bekim Sadikovic
- 1Department of Pathology and Laboratory Medicine, Western University, London, Ontario Canada.,2Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, Ontario Canada.,6Department of Pathology and Laboratory Medicine, Victoria Hospital, London Health Sciences Centre, 800 Commissioner's Road E, B10-104, London, Ontario N6A 5W9 Canada
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30
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Aref-Eshghi E, Rodenhiser DI, Schenkel LC, Lin H, Skinner C, Ainsworth P, Paré G, Hood RL, Bulman DE, Kernohan KD, Boycott KM, Campeau PM, Schwartz C, Sadikovic B, Sadikovic B. Genomic DNA Methylation Signatures Enable Concurrent Diagnosis and Clinical Genetic Variant Classification in Neurodevelopmental Syndromes. Am J Hum Genet 2018; 102:156-174. [PMID: 29304373 DOI: 10.1016/j.ajhg.2017.12.008] [Citation(s) in RCA: 112] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 12/10/2017] [Indexed: 01/23/2023] Open
Abstract
Pediatric developmental syndromes present with systemic, complex, and often overlapping clinical features that are not infrequently a consequence of Mendelian inheritance of mutations in genes involved in DNA methylation, establishment of histone modifications, and chromatin remodeling (the "epigenetic machinery"). The mechanistic cross-talk between histone modification and DNA methylation suggests that these syndromes might be expected to display specific DNA methylation signatures that are a reflection of those primary errors associated with chromatin dysregulation. Given the interrelated functions of these chromatin regulatory proteins, we sought to identify DNA methylation epi-signatures that could provide syndrome-specific biomarkers to complement standard clinical diagnostics. In the present study, we examined peripheral blood samples from a large cohort of individuals encompassing 14 Mendelian disorders displaying mutations in the genes encoding proteins of the epigenetic machinery. We demonstrated that specific but partially overlapping DNA methylation signatures are associated with many of these conditions. The degree of overlap among these epi-signatures is minimal, further suggesting that, consistent with the initial event, the downstream changes are unique to every syndrome. In addition, by combining these epi-signatures, we have demonstrated that a machine learning tool can be built to concurrently screen for multiple syndromes with high sensitivity and specificity, and we highlight the utility of this tool in solving ambiguous case subjects presenting with variants of unknown significance, along with its ability to generate accurate predictions for subjects presenting with the overlapping clinical and molecular features associated with the disruption of the epigenetic machinery.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | - Bekim Sadikovic
- Department of Pathology and Laboratory Medicine, Western University, London, ON N6A5C1, Canada; Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, ON N6A5W9, Canada.
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31
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Aref-Eshghi E, Schenkel LC, Lin H, Skinner C, Ainsworth P, Paré G, Rodenhiser D, Schwartz C, Sadikovic B. The defining DNA methylation signature of Kabuki syndrome enables functional assessment of genetic variants of unknown clinical significance. Epigenetics 2017; 12:923-933. [PMID: 28933623 DOI: 10.1080/15592294.2017.1381807] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Kabuki syndrome (KS) is caused by mutations in KMT2D, which is a histone methyltransferase involved in methylation of H3K4, a histone marker associated with DNA methylation. Analysis of >450,000 CpGs in 24 KS patients with pathogenic mutations in KMT2D and 216 controls, identified 24 genomic regions, along with 1,504 CpG sites with significant DNA methylation changes including a number of Hox genes and the MYO1F gene. Using the most differentiating and significant probes and regions we developed a "methylation variant pathogenicity (MVP) score," which enables 100% sensitive and specific identification of individuals with KS, which was confirmed using multiple public and internal patient DNA methylation databases. We also demonstrated the ability of the MVP score to accurately reclassify variants of unknown significance in subjects with apparent clinical features of KS, enabling its potential use in molecular diagnostics. These findings provide novel insights into the molecular etiology of KS and illustrate that DNA methylation patterns can be interpreted as 'epigenetic echoes' in certain clinical disorders.
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Affiliation(s)
- Erfan Aref-Eshghi
- a Department of Pathology and Laboratory Medicine , Western University , London , ON , Canada
| | - Laila C Schenkel
- a Department of Pathology and Laboratory Medicine , Western University , London , ON , Canada
| | - Hanxin Lin
- b Molecular Genetics Laboratory, Molecular Diagnostics Division , London Health Sciences Centre , London , ON , Canada . Children's Health Research Institute , London , ON , Canada
| | | | - Peter Ainsworth
- b Molecular Genetics Laboratory, Molecular Diagnostics Division , London Health Sciences Centre , London , ON , Canada . Children's Health Research Institute , London , ON , Canada
| | - Guillaume Paré
- d Department of Pathology and Molecular Medicine , McMaster University , Hamilton , ON , Canada
| | - David Rodenhiser
- e Departments of Paediatrics, Biochemistry and Oncology , Western University , London , ON , Canada
| | | | - Bekim Sadikovic
- a Department of Pathology and Laboratory Medicine , Western University , London , ON , Canada.,b Molecular Genetics Laboratory, Molecular Diagnostics Division , London Health Sciences Centre , London , ON , Canada . Children's Health Research Institute , London , ON , Canada
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