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Ma A, Grigg JR, Flaherty M, Smith J, Minoche AE, Cowley MJ, Nash BM, Ho G, Gayagay T, Lai T, Farnsworth E, Hackett EL, Slater K, Wong K, Holman KJ, Jenkins G, Cheng A, Martin F, Brown NJ, Leighton SE, Amor DJ, Goel H, Dinger ME, Bennetts B, Jamieson RV. Genome sequencing in congenital cataracts improves diagnostic yield. Hum Mutat 2021; 42:1173-1183. [PMID: 34101287 DOI: 10.1002/humu.24240] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 05/31/2021] [Accepted: 06/03/2021] [Indexed: 01/11/2023]
Abstract
Congenital cataracts are one of the major causes of childhood-onset blindness around the world. Genetic diagnosis provides benefits through avoidance of unnecessary tests, surveillance of extraocular features, and genetic family information. In this study, we demonstrate the value of genome sequencing in improving diagnostic yield in congenital cataract patients and families. We applied genome sequencing to investigate 20 probands with congenital cataracts. We examined the added value of genome sequencing across a total cohort of 52 probands, including 14 unable to be diagnosed using previous microarray and exome or panel-based approaches. Although exome or genome sequencing would have detected the variants in 35/52 (67%) of the cases, specific advantages of genome sequencing led to additional diagnoses in 10% (5/52) of the overall cohort, and we achieved an overall diagnostic rate of 77% (40/52). Specific benefits of genome sequencing were due to detection of small copy number variants (2), indels in repetitive regions (2) or single-nucleotide variants (SNVs) in GC-rich regions (1), not detectable on the previous microarray, exome sequencing, or panel-based approaches. In other cases, SNVs were identified in cataract disease genes, including those newly identified since our previous study. This study highlights the additional yield of genome sequencing in congenital cataracts.
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Affiliation(s)
- Alan Ma
- Eye Genetics Research Unit, The Children's Hospital at Westmead, Save Sight Institute, Children's Medical Research Institute, University of Sydney, Sydney, New South Wales, Australia.,Department of Clinical Genetics, Western Sydney Genetics Program, The Children's Hospital at Westmead, Sydney, New South Wales, Australia.,Specialties of Genomic Medicine & Child and Adolescent Health, Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia
| | - John R Grigg
- Eye Genetics Research Unit, The Children's Hospital at Westmead, Save Sight Institute, Children's Medical Research Institute, University of Sydney, Sydney, New South Wales, Australia.,Department of Ophthalmology, The Children's Hospital at Westmead, Sydney, New South Wales, Australia.,Specialty of Ophthalmology, University of Sydney, Sydney, New South Wales, Australia.,Save Sight Institute, Sydney Eye Hospital, Sydney, New South Wales, Australia
| | - Maree Flaherty
- Department of Ophthalmology, The Children's Hospital at Westmead, Sydney, New South Wales, Australia.,Specialty of Ophthalmology, University of Sydney, Sydney, New South Wales, Australia
| | - James Smith
- Department of Ophthalmology, The Children's Hospital at Westmead, Sydney, New South Wales, Australia.,Specialty of Ophthalmology, University of Sydney, Sydney, New South Wales, Australia
| | - Andre E Minoche
- Kinghorn Centre for Clinical Genomics, Garvan Institute of Medical Research, Darlinghurst, New South Wales, Australia
| | - Mark J Cowley
- Kinghorn Centre for Clinical Genomics, Garvan Institute of Medical Research, Darlinghurst, New South Wales, Australia.,Children's Cancer Institute, Lowy Cancer Research Centre, University of New South Wales, Randwick, New South Wales, Australia.,St Vincent's Clinical School, Faculty of Medicine, UNSW Australia, Sydney, New South Wales, Australia
| | - Benjamin M Nash
- Eye Genetics Research Unit, The Children's Hospital at Westmead, Save Sight Institute, Children's Medical Research Institute, University of Sydney, Sydney, New South Wales, Australia.,Specialties of Genomic Medicine & Child and Adolescent Health, Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia.,Sydney Genome Diagnostics, Western Sydney Genetics Program, The Children's Hospital at Westmead, Sydney, New South Wales, Australia
| | - Gladys Ho
- Specialties of Genomic Medicine & Child and Adolescent Health, Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia.,Sydney Genome Diagnostics, Western Sydney Genetics Program, The Children's Hospital at Westmead, Sydney, New South Wales, Australia
| | - Thet Gayagay
- Sydney Genome Diagnostics, Western Sydney Genetics Program, The Children's Hospital at Westmead, Sydney, New South Wales, Australia
| | - Tiffany Lai
- Sydney Genome Diagnostics, Western Sydney Genetics Program, The Children's Hospital at Westmead, Sydney, New South Wales, Australia
| | - Elizabeth Farnsworth
- Sydney Genome Diagnostics, Western Sydney Genetics Program, The Children's Hospital at Westmead, Sydney, New South Wales, Australia
| | - Emma L Hackett
- Sydney Genome Diagnostics, Western Sydney Genetics Program, The Children's Hospital at Westmead, Sydney, New South Wales, Australia
| | - Katrina Slater
- Sydney Genome Diagnostics, Western Sydney Genetics Program, The Children's Hospital at Westmead, Sydney, New South Wales, Australia
| | - Karen Wong
- Sydney Genome Diagnostics, Western Sydney Genetics Program, The Children's Hospital at Westmead, Sydney, New South Wales, Australia
| | - Katherine J Holman
- Sydney Genome Diagnostics, Western Sydney Genetics Program, The Children's Hospital at Westmead, Sydney, New South Wales, Australia
| | - Gemma Jenkins
- Sydney Genome Diagnostics, Western Sydney Genetics Program, The Children's Hospital at Westmead, Sydney, New South Wales, Australia
| | - Anson Cheng
- Eye Genetics Research Unit, The Children's Hospital at Westmead, Save Sight Institute, Children's Medical Research Institute, University of Sydney, Sydney, New South Wales, Australia
| | - Frank Martin
- Department of Ophthalmology, The Children's Hospital at Westmead, Sydney, New South Wales, Australia.,Specialty of Ophthalmology, University of Sydney, Sydney, New South Wales, Australia
| | - Natasha J Brown
- Department of Paediatrics, University of Melbourne, Parkville, Victoria, Australia.,Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Melbourne, Australia
| | | | - David J Amor
- Department of Paediatrics, University of Melbourne, Parkville, Victoria, Australia.,Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Melbourne, Australia
| | - Himanshu Goel
- Hunter Genetics, Newcastle, New South Wales, Australia
| | - Marcel E Dinger
- Kinghorn Centre for Clinical Genomics, Garvan Institute of Medical Research, Darlinghurst, New South Wales, Australia.,School of Biotechnology and Biomolecular Sciences, Faculty of Science, UNSW, Sydney, New South Wales, Australia
| | - Bruce Bennetts
- Specialties of Genomic Medicine & Child and Adolescent Health, Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia.,Sydney Genome Diagnostics, Western Sydney Genetics Program, The Children's Hospital at Westmead, Sydney, New South Wales, Australia
| | - Robyn V Jamieson
- Eye Genetics Research Unit, The Children's Hospital at Westmead, Save Sight Institute, Children's Medical Research Institute, University of Sydney, Sydney, New South Wales, Australia.,Department of Clinical Genetics, Western Sydney Genetics Program, The Children's Hospital at Westmead, Sydney, New South Wales, Australia.,Specialties of Genomic Medicine & Child and Adolescent Health, Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia
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2
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Arthur JW, Pickett HA, Barbaro PM, Kilo T, Vasireddy RS, Beilharz TH, Powell DR, Hackett EL, Bennetts B, Curtin JA, Jones K, Christodoulou J, Reddel RR, Teo J, Bryan TM. A novel cause of DKC1-related bone marrow failure: Partial deletion of the 3' untranslated region. EJHaem 2021; 2:157-166. [PMID: 35845273 PMCID: PMC9175968 DOI: 10.1002/jha2.165] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Revised: 01/03/2021] [Accepted: 01/07/2021] [Indexed: 12/11/2022]
Abstract
Telomere biology disorders (TBDs), including dyskeratosis congenita (DC), are a group of rare inherited diseases characterized by very short telomeres. Mutations in the components of the enzyme telomerase can lead to insufficient telomere maintenance in hematopoietic stem cells, resulting in the bone marrow failure that is characteristic of these disorders. While an increasing number of genes are being linked to TBDs, the causative mutation remains unidentified in 30‐40% of patients with DC. There is therefore a need for whole genome sequencing (WGS) in these families to identify novel genes, or mutations in regulatory regions of known disease‐causing genes. Here we describe a family in which a partial deletion of the 3′ untranslated region (3′ UTR) of DKC1, encoding the protein dyskerin, was identified by WGS, despite being missed by whole exome sequencing. The deletion segregated with disease across the family and resulted in reduced levels of DKC1 mRNA in the proband. We demonstrate that the DKC1 3′ UTR contains two polyadenylation signals, both of which were removed by this deletion, likely causing mRNA instability. Consistent with the major function of dyskerin in stabilization of the RNA subunit of telomerase, hTR, the level of hTR was also reduced in the proband, providing a molecular basis for his very short telomeres. This study demonstrates that the terminal region of the 3′ UTR of the DKC1 gene is essential for gene function and illustrates the importance of analyzing regulatory regions of the genome for molecular diagnosis of inherited disease.
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Affiliation(s)
- Jonathan W Arthur
- Children's Medical Research Institute Faculty of Medicine and Health, University of Sydney Westmead New South Wales Australia
| | - Hilda A Pickett
- Children's Medical Research Institute Faculty of Medicine and Health, University of Sydney Westmead New South Wales Australia
| | - Pasquale M Barbaro
- Children's Medical Research Institute Faculty of Medicine and Health, University of Sydney Westmead New South Wales Australia
| | - Tatjana Kilo
- Haematology Department Children's Hospital at Westmead Westmead New South Wales Australia
| | - Raja S Vasireddy
- Haematology Department Children's Hospital at Westmead Westmead New South Wales Australia
| | - Traude H Beilharz
- Monash Biomedicine Discovery Institute Department of Biochemistry and Molecular Biology, Monash University Clayton Victoria Australia
| | - David R Powell
- Monash Bioinformatics Platform Monash University Clayton Victoria Australia
| | - Emma L Hackett
- Department of Molecular Genetics Children's Hospital Westmead Westmead New South Wales Australia
| | - Bruce Bennetts
- Department of Molecular Genetics Children's Hospital Westmead Westmead New South Wales Australia.,Disciplines of Genetic Medicine and Child and Adolescent Health, Faculty of Medicine and Health University of Sydney Westmead New South Wales Australia
| | - Julie A Curtin
- Haematology Department Children's Hospital at Westmead Westmead New South Wales Australia
| | - Kristi Jones
- Disciplines of Genetic Medicine and Child and Adolescent Health, Faculty of Medicine and Health University of Sydney Westmead New South Wales Australia.,Department of Clinical Genetics Children's Hospital Westmead Westmead New South Wales Australia
| | - John Christodoulou
- Disciplines of Genetic Medicine and Child and Adolescent Health, Faculty of Medicine and Health University of Sydney Westmead New South Wales Australia.,Murdoch Children's Research Institute and Department of Paediatrics Melbourne Medical School Parkville Victoria Australia
| | - Roger R Reddel
- Children's Medical Research Institute Faculty of Medicine and Health, University of Sydney Westmead New South Wales Australia
| | - Juliana Teo
- Haematology Department Children's Hospital at Westmead Westmead New South Wales Australia
| | - Tracy M Bryan
- Children's Medical Research Institute Faculty of Medicine and Health, University of Sydney Westmead New South Wales Australia
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3
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Caramins M, Colebatch JG, Bainbridge MN, Scherer SS, Abrams CK, Hackett EL, Freidin MM, Jhangiani SN, Wang M, Wu Y, Muzny DM, Lindeman R, Gibbs RA. Exome sequencing identification of a GJB1 missense mutation in a kindred with X-linked spinocerebellar ataxia (SCA-X1). Hum Mol Genet 2013; 22:4329-38. [PMID: 23773993 PMCID: PMC3792691 DOI: 10.1093/hmg/ddt282] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Accepted: 06/11/2013] [Indexed: 12/21/2022] Open
Abstract
We undertook a gene identification and molecular characterization project in a large kindred originally clinically diagnosed with SCA-X1. While presenting with ataxia, this kindred also had some unique peripheral nervous system features. The implicated region on the X chromosome was delineated using haplotyping. Large deletions and duplications were excluded by array comparative genomic hybridization. Exome sequencing was undertaken in two affected subjects. The single identified X chromosome candidate variant was then confirmed to co-segregate appropriately in all affected, carrier and unaffected family members by Sanger sequencing. The variant was confirmed to be novel by comparison with dbSNP, and filtering for a minor allele frequency of <1% in 1000 Genomes project, and was not present in the NHLBI Exome Sequencing Project or a local database at the BCM HGSC. Functional experiments on transfected cells were subsequently undertaken to assess the biological effect of the variant in vitro. The variant identified consisted of a previously unidentified non-synonymous variant, GJB1 p.P58S, in the Connexin 32/Gap Junction Beta 1 gene. Segregation studies with Sanger sequencing confirmed the presence of the variant in all affected individuals and one known carrier, and the absence of the variant in unaffected members. Functional studies confirmed that the p.P58S variant reduced the number and size of gap junction plaques, but the conductance of the gap junctions was unaffected. Two X-linked ataxias have been associated with genetic loci, with the first of these recently characterized at the molecular level. This represents the second kindred with molecular characterization of X-linked ataxia, and is the first instance of a previously unreported GJB1 mutation with a dominant and permanent ataxia phenotype, although different CNS deficits have previously been reported. This pedigree has also been relatively unique in its phenotype due to the presence of central and peripheral neural abnormalities. Other X-linked SCAs with unique features might therefore also potentially represent variable phenotypic expression of other known neurological entities.
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Affiliation(s)
- Melody Caramins
- Department of Haematology and
- Department of Genetics, South Eastern Area Laboratory Services, Randwick, NSW 2031, Australia
| | - James G. Colebatch
- Department of Neurology, Prince of Wales Hospital
- Neuroscience Research Australia, Randwick, NSW 2031, Australia
| | | | - Steven S. Scherer
- Department of Neurology, The Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Charles K. Abrams
- Department of Neurology and
- Department of Physiology and Pharmacology, State University of New York, Downstate Medical Center, Brooklyn, NY 11203, USA
| | - Emma L. Hackett
- Department of Haematology and
- Department of Genetics, South Eastern Area Laboratory Services, Randwick, NSW 2031, Australia
| | | | - Shalini N. Jhangiani
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Min Wang
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Yuanqing Wu
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Donna M. Muzny
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Robert Lindeman
- Department of Haematology and
- Department of Genetics, South Eastern Area Laboratory Services, Randwick, NSW 2031, Australia
| | - Richard A. Gibbs
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
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