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Rodrigues Alves Barbosa V, Maroilley T, Diao C, Colvin-James L, Perrier R, Tarailo-Graovac M. Single variant, yet "double trouble": TSC and KBG syndrome because of a large de novo inversion. Life Sci Alliance 2024; 7:e202302115. [PMID: 38253421 PMCID: PMC10803213 DOI: 10.26508/lsa.202302115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 01/12/2024] [Accepted: 01/16/2024] [Indexed: 01/24/2024] Open
Abstract
Despite the advances in high-throughput sequencing, many rare disease patients remain undiagnosed. In particular, the patients with well-defined clinical phenotypes and established clinical diagnosis, yet missing or partial genetic diagnosis, may hold a clue to more complex genetic mechanisms of a disease that could be missed by available clinical tests. Here, we report a patient with a clinical diagnosis of Tuberous sclerosis, combined with unusual secondary features, but negative clinical tests including TSC1 and TSC2 Short-read whole-genome sequencing combined with advanced bioinformatics analyses were successful in uncovering a de novo pericentric 87-Mb inversion with breakpoints in TSC2 and ANKRD11, which explains the TSC clinical diagnosis, and confirms a second underlying monogenic disorder, KBG syndrome. Our findings illustrate how complex variants, such as large inversions, may be missed by clinical tests and further highlight the importance of well-defined clinical diagnoses in uncovering complex molecular mechanisms of a disease, such as complex variants and "double trouble" effects.
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Affiliation(s)
- Victoria Rodrigues Alves Barbosa
- https://ror.org/03yjb2x39 Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, Canada
- https://ror.org/03yjb2x39 Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, Canada
- https://ror.org/03yjb2x39 Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Canada
| | - Tatiana Maroilley
- https://ror.org/03yjb2x39 Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, Canada
- https://ror.org/03yjb2x39 Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, Canada
- https://ror.org/03yjb2x39 Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Canada
| | - Catherine Diao
- https://ror.org/03yjb2x39 Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, Canada
- https://ror.org/03yjb2x39 Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, Canada
- https://ror.org/03yjb2x39 Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Canada
| | - Leslie Colvin-James
- https://ror.org/03yjb2x39 Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, Canada
- https://ror.org/03yjb2x39 Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Canada
| | - Renee Perrier
- https://ror.org/03yjb2x39 Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, Canada
- https://ror.org/03yjb2x39 Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Canada
| | - Maja Tarailo-Graovac
- https://ror.org/03yjb2x39 Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, Canada
- https://ror.org/03yjb2x39 Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, Canada
- https://ror.org/03yjb2x39 Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Canada
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Olivucci G, Iovino E, Innella G, Turchetti D, Pippucci T, Magini P. Long read sequencing on its way to the routine diagnostics of genetic diseases. Front Genet 2024; 15:1374860. [PMID: 38510277 PMCID: PMC10951082 DOI: 10.3389/fgene.2024.1374860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Accepted: 02/26/2024] [Indexed: 03/22/2024] Open
Abstract
The clinical application of technological progress in the identification of DNA alterations has always led to improvements of diagnostic yields in genetic medicine. At chromosome side, from cytogenetic techniques evaluating number and gross structural defects to genomic microarrays detecting cryptic copy number variants, and at molecular level, from Sanger method studying the nucleotide sequence of single genes to the high-throughput next-generation sequencing (NGS) technologies, resolution and sensitivity progressively increased expanding considerably the range of detectable DNA anomalies and alongside of Mendelian disorders with known genetic causes. However, particular genomic regions (i.e., repetitive and GC-rich sequences) are inefficiently analyzed by standard genetic tests, still relying on laborious, time-consuming and low-sensitive approaches (i.e., southern-blot for repeat expansion or long-PCR for genes with highly homologous pseudogenes), accounting for at least part of the patients with undiagnosed genetic disorders. Third generation sequencing, generating long reads with improved mappability, is more suitable for the detection of structural alterations and defects in hardly accessible genomic regions. Although recently implemented and not yet clinically available, long read sequencing (LRS) technologies have already shown their potential in genetic medicine research that might greatly impact on diagnostic yield and reporting times, through their translation to clinical settings. The main investigated LRS application concerns the identification of structural variants and repeat expansions, probably because techniques for their detection have not evolved as rapidly as those dedicated to single nucleotide variants (SNV) identification: gold standard analyses are karyotyping and microarrays for balanced and unbalanced chromosome rearrangements, respectively, and southern blot and repeat-primed PCR for the amplification and sizing of expanded alleles, impaired by limited resolution and sensitivity that have not been significantly improved by the advent of NGS. Nevertheless, more recently, with the increased accuracy provided by the latest product releases, LRS has been tested also for SNV detection, especially in genes with highly homologous pseudogenes and for haplotype reconstruction to assess the parental origin of alleles with de novo pathogenic variants. We provide a review of relevant recent scientific papers exploring LRS potential in the diagnosis of genetic diseases and its potential future applications in routine genetic testing.
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Affiliation(s)
- Giulia Olivucci
- IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
- Department of Surgical and Oncological Sciences, University of Palermo, Palermo, Italy
| | - Emanuela Iovino
- IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | - Giovanni Innella
- Department of Medical and Surgical Sciences (DIMEC), University of Bologna, Bologna, Italy
- Medical Genetics Unit, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | - Daniela Turchetti
- Department of Medical and Surgical Sciences (DIMEC), University of Bologna, Bologna, Italy
- Medical Genetics Unit, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | - Tommaso Pippucci
- IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | - Pamela Magini
- Medical Genetics Unit, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
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Zou T, Neiswanger K, Feingold E, Foxman B, McNeil DW, Marazita ML, Shaffer JR. Potential risk factors and genetic variants associated with dental caries incidence in Appalachia using genome-wide survival analysis. INTERNATIONAL JOURNAL OF MOLECULAR EPIDEMIOLOGY AND GENETICS 2023; 14:19-33. [PMID: 37736056 PMCID: PMC10509536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 07/06/2023] [Indexed: 09/23/2023]
Abstract
OBJECTIVE The aim of this study was to identify the potential risk factors and genetic variants associated with dental caries incidence using survival analysis. METHODS The Center for Oral Health Research in Appalachia recruited and prospectively followed pregnant women and their children. A total of 909 children followed from birth for up to 7 years were included in this study. Annual intra-oral examinations were performed to assess dental caries experience including the approximate time to first caries incidence in the primary dentition. Cox proportional hazards models were used to assess the associations of time to first caries incidence with self-reported risk factors and 4.9 million genetic variants ascertained using a genome-wide genotyping array. RESULTS A total of 196 of 909 children (21.56%) had their first primary tooth caries event during follow-up. Household income, home water source, and mother's educational attainment were significantly associated with time to first caries incidence in the stepwise Cox model. The heritability (i.e., proportion of variance explained by genetics) of time to first caries was 0.54. Though no specific genetic variants were associated at the genome-wide significance level (P < 5E-8), we identified 14 loci at the suggestive significance level (5E-8 < P < 1E-5), some of which were located within or near genes with plausible biological functions in dental caries. CONCLUSION Our findings indicate that household income, home water source, and mother's educational attainment are independent risk factors for dental caries incidence. We nominate several suggestive loci for further investigation.
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Affiliation(s)
- Tianyu Zou
- Department of Human Genetics, School of Public Health, University of PittsburghPittsburgh, PA, USA
| | - Katherine Neiswanger
- Center for Craniofacial and Dental Genetics, Department of Oral and Craniofacial Sciences, School of Dental Medicine, University of PittsburghPittsburgh, PA, USA
| | - Eleanor Feingold
- Department of Human Genetics, School of Public Health, University of PittsburghPittsburgh, PA, USA
- Department of Biostatistics, School of Public Health, University of PittsburghPittsburgh, PA, USA
| | - Betsy Foxman
- Center for Molecular and Clinical Epidemiology of Infectious Diseases, Department of Epidemiology, University of Michigan School of Public HealthAnn Arbor, MI, USA
| | - Daniel W McNeil
- Department of Community Dentistry and Behavioral Science, College of Dentistry, University of FloridaGainesville, FL, USA
| | - Mary L Marazita
- Department of Human Genetics, School of Public Health, University of PittsburghPittsburgh, PA, USA
- Center for Craniofacial and Dental Genetics, Department of Oral and Craniofacial Sciences, School of Dental Medicine, University of PittsburghPittsburgh, PA, USA
- Clinical and Translational Sciences, School of Medicine, University of PittsburghPittsburgh, PA, USA
| | - John R Shaffer
- Department of Human Genetics, School of Public Health, University of PittsburghPittsburgh, PA, USA
- Center for Craniofacial and Dental Genetics, Department of Oral and Craniofacial Sciences, School of Dental Medicine, University of PittsburghPittsburgh, PA, USA
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Mastrorosa FK, Miller DE, Eichler EE. Applications of long-read sequencing to Mendelian genetics. Genome Med 2023; 15:42. [PMID: 37316925 DOI: 10.1186/s13073-023-01194-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Accepted: 05/18/2023] [Indexed: 06/16/2023] Open
Abstract
Advances in clinical genetic testing, including the introduction of exome sequencing, have uncovered the molecular etiology for many rare and previously unsolved genetic disorders, yet more than half of individuals with a suspected genetic disorder remain unsolved after complete clinical evaluation. A precise genetic diagnosis may guide clinical treatment plans, allow families to make informed care decisions, and permit individuals to participate in N-of-1 trials; thus, there is high interest in developing new tools and techniques to increase the solve rate. Long-read sequencing (LRS) is a promising technology for both increasing the solve rate and decreasing the amount of time required to make a precise genetic diagnosis. Here, we summarize current LRS technologies, give examples of how they have been used to evaluate complex genetic variation and identify missing variants, and discuss future clinical applications of LRS. As costs continue to decrease, LRS will find additional utility in the clinical space fundamentally changing how pathological variants are discovered and eventually acting as a single-data source that can be interrogated multiple times for clinical service.
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Affiliation(s)
| | - Danny E Miller
- Division of Genetic Medicine, Department of Pediatrics, University of Washington and Seattle Children's Hospital, Seattle, WA, 98195, USA
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, 98195, USA
- Brotman Baty Institute for Precision Medicine, University of Washington, Seattle, WA, 98195, USA
| | - Evan E Eichler
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, WA, 98195, USA.
- Howard Hughes Medical Institute, University of Washington, Seattle, WA, 98195, USA.
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Fuster-García C, García-Bohórquez B, Rodríguez-Muñoz A, Aller E, Jaijo T, Millán JM, García-García G. Usher Syndrome: Genetics of a Human Ciliopathy. Int J Mol Sci 2021; 22:ijms22136723. [PMID: 34201633 PMCID: PMC8268283 DOI: 10.3390/ijms22136723] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 06/15/2021] [Accepted: 06/16/2021] [Indexed: 12/21/2022] Open
Abstract
Usher syndrome (USH) is an autosomal recessive syndromic ciliopathy characterized by sensorineural hearing loss, retinitis pigmentosa and, sometimes, vestibular dysfunction. There are three clinical types depending on the severity and age of onset of the symptoms; in addition, ten genes are reported to be causative of USH, and six more related to the disease. These genes encode proteins of a diverse nature, which interact and form a dynamic protein network called the “Usher interactome”. In the organ of Corti, the USH proteins are essential for the correct development and maintenance of the structure and cohesion of the stereocilia. In the retina, the USH protein network is principally located in the periciliary region of the photoreceptors, and plays an important role in the maintenance of the periciliary structure and the trafficking of molecules between the inner and the outer segments of photoreceptors. Even though some genes are clearly involved in the syndrome, others are controversial. Moreover, expression of some USH genes has been detected in other tissues, which could explain their involvement in additional mild comorbidities. In this paper, we review the genetics of Usher syndrome and the spectrum of mutations in USH genes. The aim is to identify possible mutation associations with the disease and provide an updated genotype–phenotype correlation.
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Affiliation(s)
- Carla Fuster-García
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe (IIS La Fe), 46026 Valencia, Spain; (C.F.-G.); (B.G.-B.); (A.R.-M.); (E.A.); (T.J.); (G.G.-G.)
- Unidad Mixta de Enfermedades Raras IIS La Fe-Centro de Investigación Príncipe Felipe, 46026 Valencia, Spain
- Biomedical Research Network for Rare Diseases, Hospital Universitario y Politécnico La Fe, 46026 Valencia, Spain
| | - Belén García-Bohórquez
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe (IIS La Fe), 46026 Valencia, Spain; (C.F.-G.); (B.G.-B.); (A.R.-M.); (E.A.); (T.J.); (G.G.-G.)
- Unidad Mixta de Enfermedades Raras IIS La Fe-Centro de Investigación Príncipe Felipe, 46026 Valencia, Spain
| | - Ana Rodríguez-Muñoz
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe (IIS La Fe), 46026 Valencia, Spain; (C.F.-G.); (B.G.-B.); (A.R.-M.); (E.A.); (T.J.); (G.G.-G.)
- Unidad Mixta de Enfermedades Raras IIS La Fe-Centro de Investigación Príncipe Felipe, 46026 Valencia, Spain
| | - Elena Aller
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe (IIS La Fe), 46026 Valencia, Spain; (C.F.-G.); (B.G.-B.); (A.R.-M.); (E.A.); (T.J.); (G.G.-G.)
- Unidad Mixta de Enfermedades Raras IIS La Fe-Centro de Investigación Príncipe Felipe, 46026 Valencia, Spain
- Biomedical Research Network for Rare Diseases, Hospital Universitario y Politécnico La Fe, 46026 Valencia, Spain
- Genetics Unit, Hospital Universitario y Politécnico La Fe, 46026 Valencia, Spain
| | - Teresa Jaijo
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe (IIS La Fe), 46026 Valencia, Spain; (C.F.-G.); (B.G.-B.); (A.R.-M.); (E.A.); (T.J.); (G.G.-G.)
- Unidad Mixta de Enfermedades Raras IIS La Fe-Centro de Investigación Príncipe Felipe, 46026 Valencia, Spain
- Biomedical Research Network for Rare Diseases, Hospital Universitario y Politécnico La Fe, 46026 Valencia, Spain
- Genetics Unit, Hospital Universitario y Politécnico La Fe, 46026 Valencia, Spain
| | - José M. Millán
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe (IIS La Fe), 46026 Valencia, Spain; (C.F.-G.); (B.G.-B.); (A.R.-M.); (E.A.); (T.J.); (G.G.-G.)
- Unidad Mixta de Enfermedades Raras IIS La Fe-Centro de Investigación Príncipe Felipe, 46026 Valencia, Spain
- Biomedical Research Network for Rare Diseases, Hospital Universitario y Politécnico La Fe, 46026 Valencia, Spain
- Correspondence:
| | - Gema García-García
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe (IIS La Fe), 46026 Valencia, Spain; (C.F.-G.); (B.G.-B.); (A.R.-M.); (E.A.); (T.J.); (G.G.-G.)
- Unidad Mixta de Enfermedades Raras IIS La Fe-Centro de Investigación Príncipe Felipe, 46026 Valencia, Spain
- Biomedical Research Network for Rare Diseases, Hospital Universitario y Politécnico La Fe, 46026 Valencia, Spain
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Farhadi M, Razmara E, Balali M, Hajabbas Farshchi Y, Falah M. How Transmembrane Inner Ear (TMIE) plays role in the auditory system: A mystery to us. J Cell Mol Med 2021; 25:5869-5883. [PMID: 33987950 PMCID: PMC8256367 DOI: 10.1111/jcmm.16610] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 04/26/2021] [Indexed: 01/19/2023] Open
Abstract
Different cellular mechanisms contribute to the hearing sense, so it is obvious that any disruption in such processes leads to hearing impairment that greatly influences the global economy and quality of life of the patients and their relatives. In the past two decades, transmembrane inner ear (TMIE) protein has received a great deal of research interest because its impairments cause hereditary deafness in humans. This evolutionarily conserved membrane protein contributes to a fundamental complex that plays role in the maintenance and function of the sensory hair cells. Although the critical roles of the TMIE in mechanoelectrical transduction or hearing procedures have been discussed, there are little to no review papers summarizing the roles of the TMIE in the auditory system. In order to fill this gap, herein, we discuss the important roles of this protein in the auditory system including its role in mechanotransduction, olivocochlear synapse, morphology and different signalling pathways; we also review the genotype-phenotype correlation that can per se show the possible roles of this protein in the auditory system.
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Affiliation(s)
- Mohammad Farhadi
- ENT and Head and Neck Research Center and DepartmentThe Five Senses Health InstituteHazrat Rasoul Akram HospitalIran University of Medical SciencesTehranIran
| | - Ehsan Razmara
- Australian Regenerative Medicine InstituteMonash UniversityClaytonVICAustralia
| | - Maryam Balali
- ENT and Head and Neck Research Center and DepartmentThe Five Senses Health InstituteHazrat Rasoul Akram HospitalIran University of Medical SciencesTehranIran
| | - Yeganeh Hajabbas Farshchi
- Department of Cellular and Molecular BiologyTehran Medical SciencesIslamic Azad UniversityTehranIran
| | - Masoumeh Falah
- ENT and Head and Neck Research Center and DepartmentThe Five Senses Health InstituteHazrat Rasoul Akram HospitalIran University of Medical SciencesTehranIran
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Walter MA, Rezaie T, Hufnagel RB, Arno G. Ocular genetics in the genomics age. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2020; 184:860-868. [PMID: 32896097 DOI: 10.1002/ajmg.c.31844] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 08/14/2020] [Accepted: 08/17/2020] [Indexed: 12/29/2022]
Abstract
Current genetic screening methods for inherited eye diseases are concentrated on the coding exons of known disease genes (gene panels, clinical exome). These tests have a variable and often limited diagnostic rate depending on the clinical presentation, size of the gene panel and our understanding of the inheritance of the disorder (with examples described in this issue). There are numerous possible explanations for the missing heritability of these cases including undetected variants within the relevant gene (intronic, up/down-stream and structural variants), variants harbored in genes outside the targeted panel, intergenic variants, variants undetectable by the applied technology, complex/non-Mendelian inheritance, and nongenetic phenocopies. In this article we further explore and review methods to investigate these sources of missing heritability.
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Affiliation(s)
- Michael A Walter
- Department of Medical Genetics, University of Alberta, Edmonton, Alberta, Canada
| | - Tayebeh Rezaie
- National Center for Biotechnology Information, National Institutes of Health, Bethesda, Maryland, USA
| | - Robert B Hufnagel
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Gavin Arno
- University College London Institute of Ophthalmology, London, UK.,Moorfields Eye Hospital, London, UK
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