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Jacob M, Brugger M, Andres S, Wagner M, Graf E, Berutti R, Tilch E, Pavlov M, Mayerhanser K, Hoefele J, Meitinger T, Winkelmann J, Brunet T. Genome Sequencing for Cases Unsolved by Exome Sequencing: Identifying a Single-Exon Deletion in TBCK in a Case from 30 Years Ago. Neuropediatrics 2024; 55:260-264. [PMID: 38547905 DOI: 10.1055/s-0044-1782680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 07/14/2024]
Abstract
In patients with neurodevelopmental disorders (NDDs), exome sequencing (ES), the diagnostic gold standard, reveals an underlying monogenic condition in only approximately 40% of cases. We report the case of a female patient with profound NDD who died 30 years ago at the age of 3 years and for whom genome sequencing (GS) now identified a single-exon deletion in TBCK previously missed by ExomeDepth, the copy number variation (CNV) detection algorithm in ES.Deoxyribonucleic acid (DNA) was extracted from frozen muscle tissue of the index patient and the parents' blood. Genome data were analyzed for structural variants and single nucleotide variants (SUVs)/indels as part of the Bavarian Genomes consortium project.Biallelic variants in TBCK, which are linked to the autosomal recessive disorder TBCK syndrome, were detected in the affected individual: a novel frameshift variant and a deletion of exon 23, previously established as common but underrecognized pathogenic variant in individuals with TBCK syndrome. While in the foregoing ES analysis, calling algorithms for (SNVs)/indels were able to identify the frameshift variant, ExomeDepth failed to call the intragenic deletion.Our case illustrates the added value of GS for the detection of single-exon deletions for which calling from ES data remains challenging and confirms that the deletion of exon 23 in TBCK may be underdiagnosed in patients with NDDs. Furthermore, it shows the importance of "molecular or genetic autopsy" allowing genetic risk counseling for family members as well as the end of a diagnostic odyssey of 30 years.
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Affiliation(s)
- Maureen Jacob
- Institute of Human Genetics, Klinikum rechts der Isar, Technical University of Munich, School of Medicine and Health, Munich, Germany
- Bavarian Genomes Network for Rare Disorders
| | - Melanie Brugger
- Institute of Human Genetics, Klinikum rechts der Isar, Technical University of Munich, School of Medicine and Health, Munich, Germany
- Bavarian Genomes Network for Rare Disorders
| | - Stephanie Andres
- Center of Human Genetics and Laboratory Diagnostics, Martinsried, Germany
| | - Matias Wagner
- Institute of Human Genetics, Klinikum rechts der Isar, Technical University of Munich, School of Medicine and Health, Munich, Germany
- Bavarian Genomes Network for Rare Disorders
- Dr. v. Hauner Children's Hospital, Department of Pediatric Neurology and Developmental Medicine, LMU - University of Munich, Munich, Germany
- Institute of Neurogenomics, Helmholtz Zentrum München, Munich, Germany
| | - Elisabeth Graf
- Institute of Human Genetics, Klinikum rechts der Isar, Technical University of Munich, School of Medicine and Health, Munich, Germany
- Bavarian Genomes Network for Rare Disorders
| | - Riccardo Berutti
- Institute of Human Genetics, Klinikum rechts der Isar, Technical University of Munich, School of Medicine and Health, Munich, Germany
- Bavarian Genomes Network for Rare Disorders
- Institute of Neurogenomics, Helmholtz Zentrum München, Munich, Germany
| | - Erik Tilch
- Institute of Human Genetics, Klinikum rechts der Isar, Technical University of Munich, School of Medicine and Health, Munich, Germany
- Bavarian Genomes Network for Rare Disorders
- Institute of Neurogenomics, Helmholtz Zentrum München, Munich, Germany
| | - Martin Pavlov
- Institute of Human Genetics, Klinikum rechts der Isar, Technical University of Munich, School of Medicine and Health, Munich, Germany
- Bavarian Genomes Network for Rare Disorders
- Institute of Neurogenomics, Helmholtz Zentrum München, Munich, Germany
| | - Katharina Mayerhanser
- Institute of Human Genetics, Klinikum rechts der Isar, Technical University of Munich, School of Medicine and Health, Munich, Germany
- Bavarian Genomes Network for Rare Disorders
| | - Julia Hoefele
- Institute of Human Genetics, Klinikum rechts der Isar, Technical University of Munich, School of Medicine and Health, Munich, Germany
- Bavarian Genomes Network for Rare Disorders
| | - Thomas Meitinger
- Institute of Human Genetics, Klinikum rechts der Isar, Technical University of Munich, School of Medicine and Health, Munich, Germany
- Bavarian Genomes Network for Rare Disorders
| | - Juliane Winkelmann
- Institute of Human Genetics, Klinikum rechts der Isar, Technical University of Munich, School of Medicine and Health, Munich, Germany
- Bavarian Genomes Network for Rare Disorders
- Institute of Neurogenomics, Helmholtz Zentrum München, Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Theresa Brunet
- Institute of Human Genetics, Klinikum rechts der Isar, Technical University of Munich, School of Medicine and Health, Munich, Germany
- Bavarian Genomes Network for Rare Disorders
- Dr. v. Hauner Children's Hospital, Department of Pediatric Neurology and Developmental Medicine, LMU - University of Munich, Munich, Germany
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Schubert C, Milverton J, Goodall S, Merlin T. A systematic review to assess the utility of genomic autopsy using exome or genome sequencing in cases of congenital anomalies and perinatal death. Genet Med 2024; 26:101159. [PMID: 38704678 DOI: 10.1016/j.gim.2024.101159] [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: 01/21/2024] [Revised: 04/26/2024] [Accepted: 04/26/2024] [Indexed: 05/06/2024] Open
Abstract
PURPOSE Exome or genome sequencing (ES or GS) can identify genetic causes of otherwise unexplained congenital anomaly and perinatal death (PND) but is not routine practice. The evidence base for "genomic autopsy" after termination of pregnancy for fetal anomaly (TOPFA) and PND has been synthesized to determine the value of this investigation. METHODS We conducted a systematic review and meta-analysis of studies meeting prespecified inclusion criteria and containing ≥10 cases of TOPFA or PND (with or without major congenital abnormality), in which ES or GS was conducted. We determined test performance, including diagnostic yield, accuracy, and reliability. We also reported outcomes associated with clinical utility and harms, where described. RESULTS From 2245 potentially eligible studies, 32 publications were eligible and had data extracted, representing 2120 cases that could be meta-analyzed. No diagnostic accuracy or comparative studies were identified, although some analysis of concordance between different ES/GS methodologies could be performed. Studies reporting parent-related outcomes or long-term follow-up did not do so in a systematic or quantifiable manner. CONCLUSION Evidence suggests that approximately one-fourth to one-third of fetal losses associated with TOPFA or unexplained PND are associated with a genetic cause identifiable on ES or GS-albeit this estimate varies depending on phenotypic and background risk factors. Despite the large body of evidence on ES and GS, little research has attempted to validate the accuracy of testing, nor measure the clinical or societal outcomes in families that follow the diagnostic investigation in this context.
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Affiliation(s)
- Camille Schubert
- Adelaide Health Technology Assessment (AHTA), School of Public Health, University of Adelaide, Adelaide, SA, Australia.
| | - Joanne Milverton
- Adelaide Health Technology Assessment (AHTA), School of Public Health, University of Adelaide, Adelaide, SA, Australia
| | - Stephen Goodall
- Centre for Health Economics Research and Evaluation, Faculty of Health, University of Technology Sydney, Sydney, NSW, Australia
| | - Tracy Merlin
- Adelaide Health Technology Assessment (AHTA), School of Public Health, University of Adelaide, Adelaide, SA, Australia
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Skrypnyk C, AlHarmi R. Molecular autopsy by proxy: relevance for genetic counseling in rare genetic disorders. Front Genet 2024; 15:1400295. [PMID: 38859940 PMCID: PMC11163115 DOI: 10.3389/fgene.2024.1400295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Accepted: 04/25/2024] [Indexed: 06/12/2024] Open
Abstract
Background Rare genetic disorders may result in death before a definitive clinical diagnosis is established. Aim This study aims to outline the processes and challenges in managing, from a genetic perspective, couples who lost children affected by rare genetic disorders. Results Six couples who experienced child loss due to rare genetic disorders, seen by the primary author at genetic evaluation and counseling sessions, were retrospectively analyzed. Four out of 6 couples reported consanguinity. Exome and genome sequencing were performed for the parents. Carrier status of two rare lethal metabolic disorders was confirmed in one consanguineous couple. Three couples were carriers of 3 other rare diseases. Variants of LYST, MPV17, HEXB, ITGB4, CD3E, ASPM, TK2, COL11A2, and LAMB3 genes were identified. Six out of 10 were pathogenic variants, out of which 4 correlated with the demised children's phenotypes. One couple was negative for pathogenic variants. The last couple did not undergo genetic testing since they were beyond the fertile window. Conclusion Appropriate parental genetic evaluation and counseling are mandatory for selecting the right genetic test to certify the diagnosis postmortem, by virtue of molecular autopsy by proxy. Clarifying a rare disorder diagnosis can help couples to avoid recurrence and plan early for their next pregnancies.
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Affiliation(s)
- Cristina Skrypnyk
- Assistant Professor, Molecular Genetics, Princess Al-Jawhara Al-Ibrahim Center for Molecular Medicine, Genetics, and Inherited Disorders and Molecular Medicine Department, College of Medicine and Medical Sciences, Arabian Gulf University, Manama, Bahrain
- Consultant Medical Geneticist, University Medical Clinics, Manama, Bahrain
| | - Rawan AlHarmi
- Research Associate, Regenerative Medicine Unit, Arabian Gulf University, Manama, Bahrain
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Borghesi A. Life-threatening infections in human newborns: Reconciling age-specific vulnerability and interindividual variability. Cell Immunol 2024; 397-398:104807. [PMID: 38232634 DOI: 10.1016/j.cellimm.2024.104807] [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: 10/29/2023] [Revised: 01/05/2024] [Accepted: 01/10/2024] [Indexed: 01/19/2024]
Abstract
In humans, the interindividual variability of clinical outcome following exposure to a microorganism is immense, ranging from silent infection to life-threatening disease. Age-specific immune responses partially account for the high incidence of infection during the first 28 days of life and the related high mortality at population level. However, the occurrence of life-threatening disease in individual newborns remains unexplained. By contrast, inborn errors of immunity and their immune phenocopies are increasingly being discovered in children and adults with life-threatening viral, bacterial, mycobacterial and fungal infections. There is a need for convergence between the fields of neonatal immunology, with its in-depth population-wide characterization of newborn-specific immune responses, and clinical immunology, with its investigations of infections in patients at the cellular and molecular levels, to facilitate identification of the mechanisms of susceptibility to infection in individual newborns and the design of novel preventive and therapeutic strategies.
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Affiliation(s)
- Alessandro Borghesi
- Neonatal Intensive Care Unit, San Matteo Research Hospital, Pavia, EU, Italy; School of Life Sciences, Swiss Federal Institute of Technology, Lausanne, Switzerland.
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Abolhassani A, Fattahi Z, Beheshtian M, Fadaee M, Vazehan R, Ahangari F, Dehdahsi S, Faraji Zonooz M, Parsimehr E, Kalhor Z, Peymani F, Mozaffarpour Nouri M, Babanejad M, Noudehi K, Fatehi F, Zamanian Najafabadi S, Afroozan F, Yazdan H, Bozorgmehr B, Azarkeivan A, Sadat Mahdavi S, Nikuei P, Fatehi F, Jamali P, Ashrafi MR, Karimzadeh P, Habibi H, Kahrizi K, Nafissi S, Kariminejad A, Najmabadi H. Clinical application of next generation sequencing for Mendelian disease diagnosis in the Iranian population. NPJ Genom Med 2024; 9:12. [PMID: 38374194 PMCID: PMC10876633 DOI: 10.1038/s41525-024-00393-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 01/29/2024] [Indexed: 02/21/2024] Open
Abstract
Next-generation sequencing (NGS) has been proven to be one of the most powerful diagnostic tools for rare Mendelian disorders. Several studies on the clinical application of NGS in unselected cohorts of Middle Eastern patients have reported a high diagnostic yield of up to 48%, correlated with a high level of consanguinity in these populations. We evaluated the diagnostic utility of NGS-based testing across different clinical indications in 1436 patients from Iran, representing the first study of its kind in this highly consanguineous population. A total of 1075 exome sequencing and 361 targeted gene panel sequencing were performed over 8 years at a single clinical genetics laboratory, with the majority of cases tested as proband-only (91.6%). The overall diagnostic rate was 46.7%, ranging from 24% in patients with an abnormality of prenatal development to over 67% in patients with an abnormality of the skin. We identified 660 pathogenic or likely pathogenic variants, including 241 novel variants, associated with over 342 known genetic conditions. The highly consanguineous nature of this cohort led to the diagnosis of autosomal recessive disorders in the majority of patients (79.1%) and allowed us to determine the shared carrier status of couples for suspected recessive phenotypes in their deceased child(ren) when direct testing was not possible. We also highlight the observations of recessive inheritance of genes previously associated only with dominant disorders and provide an expanded genotype-phenotype spectrum for multiple less-characterized genes. We present the largest mutational spectrum of known Mendelian disease, including possible founder variants, throughout the Iranian population, which can serve as a unique resource for clinical genomic studies locally and beyond.
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Affiliation(s)
- Ayda Abolhassani
- Kariminejad - Najmabadi Pathology & Genetics Center, Tehran, Iran
| | - Zohreh Fattahi
- Kariminejad - Najmabadi Pathology & Genetics Center, Tehran, Iran
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | | | - Mahsa Fadaee
- Kariminejad - Najmabadi Pathology & Genetics Center, Tehran, Iran
| | - Raheleh Vazehan
- Kariminejad - Najmabadi Pathology & Genetics Center, Tehran, Iran
| | - Fatemeh Ahangari
- Kariminejad - Najmabadi Pathology & Genetics Center, Tehran, Iran
| | - Shima Dehdahsi
- Kariminejad - Najmabadi Pathology & Genetics Center, Tehran, Iran
| | | | - Elham Parsimehr
- Kariminejad - Najmabadi Pathology & Genetics Center, Tehran, Iran
| | - Zahra Kalhor
- Kariminejad - Najmabadi Pathology & Genetics Center, Tehran, Iran
| | - Fatemeh Peymani
- Kariminejad - Najmabadi Pathology & Genetics Center, Tehran, Iran
| | | | - Mojgan Babanejad
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Khadijeh Noudehi
- Kariminejad - Najmabadi Pathology & Genetics Center, Tehran, Iran
| | - Fatemeh Fatehi
- Kariminejad - Najmabadi Pathology & Genetics Center, Tehran, Iran
| | | | - Fariba Afroozan
- Kariminejad - Najmabadi Pathology & Genetics Center, Tehran, Iran
| | - Hilda Yazdan
- Kariminejad - Najmabadi Pathology & Genetics Center, Tehran, Iran
| | - Bita Bozorgmehr
- Kariminejad - Najmabadi Pathology & Genetics Center, Tehran, Iran
| | - Azita Azarkeivan
- Kariminejad - Najmabadi Pathology & Genetics Center, Tehran, Iran
| | | | - Pooneh Nikuei
- Molecular Medicine Research Center, Hormozgan Health Institute, Hormozgan University of Medical Sciences, Bandar Abbas, Iran
- Nasle Salem Genetic Counseling Center, Bandar Abbas, Iran
| | - Farzad Fatehi
- Department of Neurology, Neuromuscular Research Center, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Payman Jamali
- Genetic Counseling Center, Shahroud Welfare Organization, Semnan, Iran
| | | | - Parvaneh Karimzadeh
- Pediatric Neurology Department, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Haleh Habibi
- Hamedan University of Medical Science, Hamedan, Iran
| | - Kimia Kahrizi
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Shahriar Nafissi
- Department of Neurology, Neuromuscular Research Center, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | | | - Hossein Najmabadi
- Kariminejad - Najmabadi Pathology & Genetics Center, Tehran, Iran.
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran.
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Al-Kouatly HB, Shivashankar K, Mossayebi MH, Makhamreh M, Critchlow E, Gao Z, Fasehun LK, Alkuraya FS, Ryan EE, Hegde M, Wodoslawsky S, Hughes J, Berger SI. Diagnostic yield from prenatal exome sequencing for non-immune hydrops fetalis: A systematic review and meta-analysis. Clin Genet 2023; 103:503-512. [PMID: 36757664 DOI: 10.1111/cge.14309] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 01/18/2023] [Accepted: 02/06/2023] [Indexed: 02/10/2023]
Abstract
Non-immune hydrops fetalis (NIHF) has multiple genetic etiologies diagnosable by exome sequencing (ES). We evaluated the yield of prenatal ES for NIHF, and the contribution of additional clinical findings and history. Systematic review was performed with PROSPERO tag 232951 using CINAHL, PubMed, and Ovid MEDLINE from January 1, 2000 through December 1, 2021. Selected studies performed ES to augment standard prenatal diagnostic approaches. Cases meeting a strict NIHF phenotype were tabulated with structured data imputed from papers or requested from authors. Genetic variants and diagnostic outcomes were harmonized across studies using current ACMG and ClinGen variant classification guidelines. Thirty-one studies reporting 445 NIHF cases had a 37% (95% CI: 32%-41%) diagnostic rate. There was no significant difference between isolated NIHF and NIHF with fetal malformations or between recurrent and simplex cases. Diagnostic rate was higher for consanguineous than non-consanguineous cases. Disease categories included RASopathies (24%), neuromuscular (21%), metabolic (17%), lymphatic (13%), other syndromes (9%), cardiovascular (5%), hematologic (2%), skeletal (2%), and other categories (7%). Inheritance patterns included recessive (55%), dominant (41%), and X-linked (4%). ES should be considered in the diagnostic workup of NIHF with and without associated ultrasound findings regardless of history of recurrence or consanguinity.
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Affiliation(s)
- Huda B Al-Kouatly
- Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Kavya Shivashankar
- Department of Obstetrics and Gynecology, University of Illinois College of Medicine, Chicago, Illinois, USA
| | - Matthew H Mossayebi
- Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Mona Makhamreh
- Department of Obstetrics and Gynecology, Maimonides Medical Center, Brooklyn, New York, USA
| | - Elizabeth Critchlow
- Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Zimeng Gao
- Department of Obstetrics and Gynecology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Luther-King Fasehun
- Department of Epidemiology and Biostatistics, College of Public Health, Temple University, Philadelphia, Pennsylvania, USA
| | - Fowzan S Alkuraya
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Erin E Ryan
- Genomic Data / Genetic Counseling, GeneDx, Gaithersburg, Maryland, USA
| | - Madhuri Hegde
- Global Lab Services, PerkinElmer Genomics, Atlanta, Georgia, USA
| | - Sascha Wodoslawsky
- Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Joel Hughes
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Seth I Berger
- Center for Genetic Medicine Research, Children's National Research Institute, Washington, DC, USA
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Protasova MS, Andreeva TV, Klyushnikov SA, Illarioshkin SN, Rogaev EI. Genetic Variant in GRM1 Underlies Congenital Cerebellar Ataxia with No Obvious Intellectual Disability. Int J Mol Sci 2023; 24:ijms24021551. [PMID: 36675067 PMCID: PMC9865416 DOI: 10.3390/ijms24021551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 12/29/2022] [Accepted: 01/03/2023] [Indexed: 01/15/2023] Open
Abstract
Metabotropic glutamate receptor 1 (mGluR1) plays a crucial role in slow excitatory postsynaptic conductance, synapse formation, synaptic plasticity, and motor control. The GRM1 gene is expressed mainly in the brain, with the highest expression in the cerebellum. Mutations in the GRM1 gene have previously been known to cause autosomal recessive and autosomal dominant spinocerebellar ataxias. In this study, whole-exome sequencing of a patient from a family of Azerbaijani origin with a diagnosis of congenital cerebellar ataxia was performed, and a new homozygous missense mutation in the GRM1 gene was identified. The mutation leads to the homozygous amino acid substitution of p.Thr824Arg in an evolutionarily highly conserved region encoding the transmembrane domain 7, which is critical for ligand binding and modulating of receptor activity. This is the first report in which a mutation has been identified in the last transmembrane domain of the mGluR1, causing a congenital autosomal recessive form of cerebellar ataxia with no obvious intellectual disability. Additionally, we summarized all known presumable pathogenic genetic variants in the GRM1 gene to date. We demonstrated that multiple rare variants in the GRM1 underlie a broad diversity of clinical neurological and behavioral phenotypes depending on the nature and protein topology of the mutation.
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Affiliation(s)
- Maria S. Protasova
- Vavilov Institute of General Genetics, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Tatiana V. Andreeva
- Vavilov Institute of General Genetics, Russian Academy of Sciences, 119991 Moscow, Russia
- Center for Genetics and Life Science, Department of Genetics, Sirius University of Science and Technology, 354340 Sochi, Russia
- Centre for Genetics and Genetic Technologies, Department of Genetics, Faculty of Biology, Lomonosov Moscow State University, 119192 Moscow, Russia
- Correspondence: (T.V.A.); (E.I.R.)
| | | | | | - Evgeny I. Rogaev
- Vavilov Institute of General Genetics, Russian Academy of Sciences, 119991 Moscow, Russia
- Center for Genetics and Life Science, Department of Genetics, Sirius University of Science and Technology, 354340 Sochi, Russia
- Department of Psychiatry, UMass Chan Medical School, Shrewsbury, MA 01545, USA
- Correspondence: (T.V.A.); (E.I.R.)
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Postel MD, Culver JO, Ricker C, Craig DW. Transcriptome analysis provides critical answers to the "variants of uncertain significance" conundrum. Hum Mutat 2022; 43:1590-1608. [PMID: 35510381 PMCID: PMC9560997 DOI: 10.1002/humu.24394] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 03/16/2022] [Accepted: 04/26/2022] [Indexed: 12/30/2022]
Abstract
While whole-genome and exome sequencing have transformed our collective understanding of genetics' role in disease pathogenesis, there are certain conditions and populations for whom DNA-level data fails to identify the underlying genetic etiology. Specifically, patients of non-White race and non-European ancestry are disproportionately affected by "variants of unknown/uncertain significance" (VUS), limiting the scope of precision medicine for minority patients and perpetuating health disparities. VUS often include deep intronic and splicing variants which are difficult to interpret from DNA data alone. RNA analysis can illuminate the consequences of VUS, thereby allowing for their reclassification as pathogenic versus benign. Here we review the critical role transcriptome analysis plays in clarifying VUS in both neoplastic and non-neoplastic diseases.
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Affiliation(s)
- Mackenzie D. Postel
- Department of Translational GenomicsUniversity of Southern CaliforniaLos AngelesCaliforniaUSA
- Keck School of Medicine of USCUniversity of Southern CaliforniaLos AngelesCaliforniaUSA
| | - Julie O. Culver
- Keck School of Medicine of USCUniversity of Southern CaliforniaLos AngelesCaliforniaUSA
| | - Charité Ricker
- Keck School of Medicine of USCUniversity of Southern CaliforniaLos AngelesCaliforniaUSA
| | - David W. Craig
- Department of Translational GenomicsUniversity of Southern CaliforniaLos AngelesCaliforniaUSA
- Keck School of Medicine of USCUniversity of Southern CaliforniaLos AngelesCaliforniaUSA
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Østergård Jensen S, Christen M, Rondahl V, Holland CT, Jagannathan V, Leeb T, Giger U. EHBP1L1 Frameshift Deletion in English Springer Spaniel Dogs with Dyserythropoietic Anemia and Myopathy Syndrome (DAMS) or Neonatal Losses. Genes (Basel) 2022; 13:genes13091533. [PMID: 36140701 PMCID: PMC9498568 DOI: 10.3390/genes13091533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 08/20/2022] [Accepted: 08/22/2022] [Indexed: 11/16/2022] Open
Abstract
Hereditary myopathies are well documented in dogs, whereas hereditary dyserythropoietic anemias are rarely seen. The aim of this study was to further characterize the clinical and clinicopathological features of and to identify the causative genetic variant for a dyserythropoietic anemia and myopathy syndrome (DAMS) in English springer spaniel dogs (ESSPs). Twenty-six ESSPs, including five dogs with DAMS and two puppies that died perinatally, were studied. Progressive weakness, muscle atrophy—particularly of the temporal and pelvic muscles—trismus, dysphagia, and regurgitation due to megaesophagus were observed at all ages. Affected dogs had a non-regenerative, microcytic hypochromic anemia with metarubricytosis, target cells, and acanthocytes. Marked erythroid hyperplasia and dyserythropoiesis with non-orderly maturation of erythrocytes and inappropriate microcytic metarubricytosis were present. Muscle biopsies showed centralized nuclei, central pallor, lipocyte infiltrates, and fibrosis, which was consistent with centronuclear myopathy. The genome sequencing of two affected dogs was compared to 782 genomes of different canine breeds. A homozygous frameshift single-base deletion in EHBP1L1 was identified; this gene was not previously associated with DAMS. Pedigree analysis confirmed that the affected ESSPs were related. Variant genotyping showed appropriate complete segregation in the family, which was consistent with an autosomal recessive mode of inheritance. This study expands the known genotype–phenotype correlation of EHBP1L1 and the list of potential causative genes in dyserythropoietic anemias and myopathies in humans. EHBP1L1 deficiency was previously reported as perinatally lethal in humans and knockout mice. Our findings enable the genetic testing of ESSP dogs for early diagnosis and disease prevention through targeted breeding strategies.
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Affiliation(s)
- Sarah Østergård Jensen
- Clinical Pathology Laboratory, The Swedish University of Agricultural Sciences, 750 07 Uppsala, Sweden
- AniCura Small Animal Referral Hospital Bagarmossen, Ljusnevägen 17, Bagarmossen, 128 48 Stockholm, Sweden
| | - Matthias Christen
- Institute of Genetics, Vetsuisse Faculty, University of Bern, Bremgartenstrasse 109a, 3001 Bern, Switzerland
| | | | - Christopher T. Holland
- Merewether Veterinary Hospital, Suite 2, 25 Llewellyn St, Merewether, NSW 2291, Australia
| | - Vidhya Jagannathan
- Institute of Genetics, Vetsuisse Faculty, University of Bern, Bremgartenstrasse 109a, 3001 Bern, Switzerland
| | - Tosso Leeb
- Institute of Genetics, Vetsuisse Faculty, University of Bern, Bremgartenstrasse 109a, 3001 Bern, Switzerland
| | - Urs Giger
- Vetsuisse Faculty, University of Zürich, Winterthurerstrasse 260, 8057 Zürich, Switzerland
- Correspondence: ; Tel.: +1-610-565-1427
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Shelton GD, Minor KM, Guo LT, Thomas-Hollands A, Walsh KA, Friedenberg SG, Cullen JN, Mickelson JR. An EHPB1L1 Nonsense Mutation Associated with Congenital Dyserythropoietic Anemia and Polymyopathy in Labrador Retriever Littermates. Genes (Basel) 2022; 13:genes13081427. [PMID: 36011338 PMCID: PMC9407898 DOI: 10.3390/genes13081427] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 08/05/2022] [Accepted: 08/08/2022] [Indexed: 12/30/2022] Open
Abstract
In this report, we describe a novel genetic basis for congenital dyserythropoietic anemia and polymyopathy in Labrador Retriever littermates characterized by incidental detection of marked microcytosis, inappropriate metarubricytosis, pelvic limb weakness and muscle atrophy. A similar syndrome has been described in English Springer Spaniel littermates with an early onset of anemia, megaesophagus, generalized muscle atrophy and cardiomyopathy. Muscle histopathology in both breeds showed distinctive pathological changes consistent with congenital polymyopathy. Using whole genome sequencing and mapping to the CanFam4 (Canis lupus familiaris reference assembly 4), a nonsense variant in the EHBP1L1 gene was identified in a homozygous form in the Labrador Retriever littermates. The mutation produces a premature stop codon that deletes approximately 90% of the protein. This variant was not present in the English Springer Spaniels. Currently, EHPB1L1 is described as critical to actin cytoskeletal organization and apical-directed transport in polarized epithelial cells, and through connections with Rab8 and a BIN1-dynamin complex generates membrane vesicles in the endocytic recycling compartment. Furthermore, EHBP1L1 knockout mice die early and develop severe anemia. The connection of EHBP1L1 to BIN1 and DMN2 functions is particularly interesting due to BIN1 and DMN2 mutations being causative in forms of centronuclear myopathy. This report, along with an independent study conducted by another group, are the first reports of an association of EHBP1L1 mutations with congenital dyserythropoietic anemia and polymyopathy.
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Affiliation(s)
- G. Diane Shelton
- Department of Pathology, School of Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Katie M. Minor
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, Saint Paul, MN 55108, USA
| | - Ling T. Guo
- Department of Pathology, School of Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Alison Thomas-Hollands
- Department of Clinical Sciences and Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Koranda A. Walsh
- Department of Clinical Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA 19104, USA
| | - Steven G. Friedenberg
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, University of Minnesota, Saint Paul, MN 55108, USA
| | - Jonah N. Cullen
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, University of Minnesota, Saint Paul, MN 55108, USA
| | - James R. Mickelson
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, Saint Paul, MN 55108, USA
- Correspondence:
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Protasova MS, Gusev FE, Andreeva TV, Klyushnikov SA, Illarioshkin SN, Rogaev EI. Novel genes bearing mutations in rare cases of early-onset ataxia with cerebellar hypoplasia. Eur J Hum Genet 2022; 30:703-711. [PMID: 35351988 DOI: 10.1038/s41431-022-01088-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 02/09/2022] [Accepted: 03/10/2022] [Indexed: 12/13/2022] Open
Abstract
We propose an approach for the identification of mutant genes for rare diseases in single cases of unknown etiology. All genes with rare biologically significant variants sorted from individual exome data are tested further for profiling of their spatial-temporal and cell/tissue specific expression compared to that of their paralogs. We developed a simple bioinformatics tool ("Essential Paralogue by Expression" (EPbE)) for such analysis. Here, we present rare clinical forms of early ataxia with cerebellar hypoplasia. Using whole-exome sequencing and the EPbE tool, we identified two novel mutant genes previously not associated with congenital human diseases. In Family I, the unique missense mutation (p.Lys258Glu) was found in the LRCH2 gene inherited in an X-linked manner. p.Lys258Glu occurs in the evolutionarily invariant site of the leucine-rich repeat domain of LRCH2. In Family II and Family III, the identical genetic variant was found in the CSMD1 gene inherited as an autosomal-recessive trait. The variant leads to amino acid substitution p.Gly2979Ser in a highly conserved region of the complement-interacting domain of CSMD1. The LRCH2 gene for Family I patients (in which congenital cerebellar hypoplasia was associated with demyelinating polyneuropathy) is expressed in Schwann and precursor Schwann cells and predominantly over its paralogous genes in the developing cerebellar cortex. The CSMD1 gene is predominantly expressed over its paralogous genes in the cerebellum, specifically in the period of late childhood. Thus, the comparative spatial-temporal expression of the selected genes corresponds to the neurological manifestations of the disease.
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Affiliation(s)
- Maria S Protasova
- Laboratory of Evolutionary Genomics, Department of Genomics and Human Genetics, Vavilov Institute of General Genetics Russian Academy of Sciences, 119333, Moscow, Russia
| | - Fedor E Gusev
- Laboratory of Evolutionary Genomics, Department of Genomics and Human Genetics, Vavilov Institute of General Genetics Russian Academy of Sciences, 119333, Moscow, Russia
| | - Tatiana V Andreeva
- Laboratory of Evolutionary Genomics, Department of Genomics and Human Genetics, Vavilov Institute of General Genetics Russian Academy of Sciences, 119333, Moscow, Russia.,Faculty of Biology, Lomonosov Moscow State University, 119234, Moscow, Russia
| | - Sergey A Klyushnikov
- Department of Neurogenetics, Research Center of Neurology, 123367, Moscow, Russia
| | | | - Evgeny I Rogaev
- Laboratory of Evolutionary Genomics, Department of Genomics and Human Genetics, Vavilov Institute of General Genetics Russian Academy of Sciences, 119333, Moscow, Russia. .,Center for Genetics and Life Science, Sirius University of Science and Technology, 354340, Sochi, Russia. .,Department of Psychiatry, UMass Chan Medical School, Shrewsbury, MA, 01545, USA.
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