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Niu Y, Xu J, Ye R, Dai Z, Jin L, Geng W. Crouzon syndrome complicated with binocular strabismus and extraocular muscle fibrosis: a case report. J Med Case Rep 2023; 17:51. [PMID: 36755349 PMCID: PMC9909971 DOI: 10.1186/s13256-022-03709-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Accepted: 12/05/2022] [Indexed: 02/10/2023] Open
Abstract
BACKGROUND Crouzon syndrome, a rare genetic disorder characterized by premature closure of coronal sutures, results in skull and facial deformities along with abnormal brain and ocular development. CASE PRESENTATION Here, we report a case of a 27-year-old ethnic han male patient who presented with complex binocular strabismus secondary to Crouzon syndrome. At the time of surgery, extraocular muscles were found to be fibrotic and results of the pathological examination revealed degeneration of muscle fibers, which were replaced by adipose tissue. The entire exome sequencing DNA testing indicated that the patient and his father possessed the fibroblast growth factor receptor 2 (FGFR2) gene c.G812T:p.G271V heterozygous mutation. Binocular strabismus corrective surgery was performed in this patient with a satisfactory outcome. CONCLUSIONS This case demonstrates that Crouzon syndrome patients can show an FGFR2 gene c.G812T:p.G271V mutation and display clinical symptoms such as extraocular muscle fibrosis, exotropia, exophthalmos, and a pointed head deformity.
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Affiliation(s)
- Yuling Niu
- Department of Ophthalmology, People's Hospital of Shenzhen Baoan District, Shenzhen, 518101, China.
| | - Jin Xu
- grid.508335.80000 0004 5373 5174Department of Ophthalmology, People’s Hospital of Shenzhen Baoan District, Shenzhen, 518101 China
| | - Rushan Ye
- grid.508335.80000 0004 5373 5174Department of Ophthalmology, People’s Hospital of Shenzhen Baoan District, Shenzhen, 518101 China
| | - Zixian Dai
- grid.508335.80000 0004 5373 5174Department of Ophthalmology, People’s Hospital of Shenzhen Baoan District, Shenzhen, 518101 China
| | - Ling Jin
- grid.508335.80000 0004 5373 5174Department of Ophthalmology, People’s Hospital of Shenzhen Baoan District, Shenzhen, 518101 China
| | - Wenwen Geng
- grid.508335.80000 0004 5373 5174Department of Ophthalmology, People’s Hospital of Shenzhen Baoan District, Shenzhen, 518101 China
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Yıldız Bölükbaşı E, Karolak JA, Szafranski P, Gambin T, Willard N, Abman SH, Galambos C, Kinsella JP, Stankiewicz P. High-level gonosomal mosaicism for a pathogenic non-coding CNV deletion of the lung-specific FOXF1 enhancer in an unaffected mother of an infant with ACDMPV. Mol Genet Genomic Med 2022; 10:e2062. [PMID: 36124617 PMCID: PMC9651602 DOI: 10.1002/mgg3.2062] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 08/22/2022] [Accepted: 09/08/2022] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Alveolar capillary dysplasia with misalignment of pulmonary veins (ACDMPV) results from haploinsufficiency of the mesenchymal transcription factor FOXF1 gene. To date, only one case of an ACDMPV-causative CNV deletion inherited from a very-low level somatic mosaic mother has been reported. METHODS Clinical, histopathological, and molecular studies, including whole genome sequencing, chromosomal microarray analysis, qPCR, and Sanger sequencing, followed by in vitro fertilization (IVF) with preimplantation genetic testing (PGT) were used to study a family with a deceased neonate with ACDMPV. RESULTS A pathogenic CNV deletion of the lung-specific FOXF1 enhancer in the proband was found to be inherited from an unaffected mother, 36% mosaic for this deletion in her peripheral blood cells. The qPCR analyses of saliva, buccal cells, urine, nail, and hair samples revealed 19%, 18%, 15%, 19%, and 27% variant allele fraction, respectively, indicating a high recurrence risk. Grandparental studies revealed that the deletion arose on the mother's paternal chromosome 16. PGT studies revealed 44% embryos with the deletion, reflecting high-level germline mosaicism. CONCLUSION Our data further demonstrate the importance of parental testing in ACDMPV families and reproductive usefulness of IVF with PGT in families with high-level parental gonosomal mosaicism.
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Affiliation(s)
| | - Justyna A. Karolak
- Chair and Department of Genetics and Pharmaceutical MicrobiologyPoznan University of Medical SciencesPoznanPoland
| | | | - Tomasz Gambin
- Institute of Computer ScienceWarsaw University of TechnologyWarsawPoland
| | - Nicholas Willard
- Department of Pathology and Laboratory MedicineUniversity of Colorado Anschutz Medical CampusAuroraColoradoUSA
| | - Steven H. Abman
- Department of PediatricsUniversity of Colorado Anschutz Medical CampusAuroraColoradoUSA
| | - Csaba Galambos
- Department of Pathology and Laboratory MedicineUniversity of Colorado Anschutz Medical CampusAuroraColoradoUSA,Department of PediatricsUniversity of Colorado Anschutz Medical CampusAuroraColoradoUSA
| | - John P. Kinsella
- Department of PediatricsUniversity of Colorado Anschutz Medical CampusAuroraColoradoUSA
| | - Paweł Stankiewicz
- Department of Molecular & Human GeneticsBaylor College of MedicineHoustonTexasUSA
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3
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Domogala DD, Gambin T, Zemet R, Wu CW, Schulze KV, Yang Y, Wilson TA, Machol I, Liu P, Stankiewicz P. Detection of low-level parental somatic mosaicism for clinically relevant SNVs and indels identified in a large exome sequencing dataset. Hum Genomics 2021; 15:72. [PMID: 34930489 PMCID: PMC8686574 DOI: 10.1186/s40246-021-00369-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 11/27/2021] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Due to the limitations of the current routine diagnostic methods, low-level somatic mosaicism with variant allele fraction (VAF) < 10% is often undetected in clinical settings. To date, only a few studies have attempted to analyze tissue distribution of low-level parental mosaicism in a large clinical exome sequencing (ES) cohort. METHODS Using a customized bioinformatics pipeline, we analyzed apparent de novo single-nucleotide variants or indels identified in the affected probands in ES trio data at Baylor Genetics clinical laboratories. Clinically relevant variants with VAFs between 30 and 70% in probands and lower than 10% in one parent were studied. DNA samples extracted from saliva, buccal cells, redrawn peripheral blood, urine, hair follicles, and nail, representing all three germ layers, were tested using PCR amplicon next-generation sequencing (amplicon NGS) and droplet digital PCR (ddPCR). RESULTS In a cohort of 592 clinical ES trios, we found 61 trios, each with one parent suspected of low-level mosaicism. In 21 parents, the variants were validated using amplicon NGS and seven of them by ddPCR in peripheral blood DNA samples. The parental VAFs in blood samples varied between 0.08 and 9%. The distribution of VAFs in additional tissues ranged from 0.03% in hair follicles to 9% in re-drawn peripheral blood. CONCLUSIONS Our study illustrates the importance of analyzing ES data using sensitive computational and molecular methods for low-level parental somatic mosaicism for clinically relevant variants previously diagnosed in routine clinical diagnostics as apparent de novo.
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Affiliation(s)
- Daniel D Domogala
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA.,Graduate Program in Diagnostic Genetics, School of Health Professions, University of Texas at MD Anderson, Houston, TX, USA
| | - Tomasz Gambin
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA.,Institute of Computer Science, Warsaw University of Technology, Warsaw, Poland
| | - Roni Zemet
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA
| | - Chung Wah Wu
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA.,Baylor Genetics, Houston, TX, USA
| | - Katharina V Schulze
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA.,Baylor Genetics, Houston, TX, USA
| | - Yaping Yang
- AiLife Diagnostics, 1920 Country Place Pkwy Suite 100, Pearland, TX, USA
| | - Theresa A Wilson
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA
| | | | - Pengfei Liu
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA.,Baylor Genetics, Houston, TX, USA
| | - Paweł Stankiewicz
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA.
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Abstract
Importance Craniosynostosis is a fetal condition caused by premature closure of the cranial sutures. Through provider awareness, we can raise suspicion in high-risk individuals, increase prenatal detection, optimize genetic testing, perform appropriate antenatal surveillance and delivery planning, and allow for a comprehensive, multidisciplinary approach to treatment. Objective The aim of this study was to review what is currently known regarding the genetics, pathophysiology, diagnosis, and treatment of craniosynostosis for the obstetric care provider. Evidence Acquisition A comprehensive literature review was performed using the PubMed database with the search term "craniosynostosis." The search was limited to the English language. Results A total of 220 articles were identified, and a total of 53 were used in completion of this article. The results highlight the multiple factors involved with abnormal suture formation, including various genetic factors. Although rare at this time, prenatal detection can allow families to prepare and practitioners to provide appropriate clinical treatment. Both 3-dimensional sonography and magnetic resonance imaging have been identified as modalities to aid in detection for high-risk individuals. Early referral allows for less-invasive surgical outcomes with lower complication rates. Results Familiarity with craniosynostosis among obstetric providers can improve patient counseling, prenatal detection rates, and appropriate antepartum, intrapartum, and postpartum counseling.
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Tønne E, Due-Tønnessen BJ, Mero IL, Wiig US, Kulseth MA, Vigeland MD, Sheng Y, von der Lippe C, Tveten K, Meling TR, Helseth E, Heimdal KR. Benefits of clinical criteria and high-throughput sequencing for diagnosing children with syndromic craniosynostosis. Eur J Hum Genet 2021; 29:920-929. [PMID: 33288889 PMCID: PMC8187391 DOI: 10.1038/s41431-020-00788-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 11/04/2020] [Accepted: 11/20/2020] [Indexed: 12/13/2022] Open
Abstract
An accurate diagnosis of syndromic craniosynostosis (CS) is important for personalized treatment, surveillance, and genetic counselling. We describe detailed clinical criteria for syndromic CS and the distribution of genetic diagnoses within the cohort. The prospective registry of the Norwegian National Unit for Craniofacial Surgery was used to retrieve individuals with syndromic CS born between 1 January 2002 and 30 June 2019. All individuals were assessed by a clinical geneticist and classified using defined clinical criteria. A stepwise approach consisting of single-gene analysis, comparative genomic hybridization (aCGH), and exome-based high-throughput sequencing, first filtering for 72 genes associated with syndromic CS, followed by an extended trio-based panel of 1570 genes were offered to all syndromic CS cases. A total of 381 individuals were registered with CS, of whom 104 (27%) were clinically classified as syndromic CS. Using the single-gene analysis, aCGH, and custom-designed panel, a genetic diagnosis was confirmed in 73% of the individuals (n = 94). The diagnostic yield increased to 84% after adding the results from the extended trio-based panel. Common causes of syndromic CS were found in 53 individuals (56%), whereas 26 (28%) had other genetic syndromes, including 17 individuals with syndromes not commonly associated with CS. Only 15 individuals (16%) had negative genetic analyses. Using the defined combination of clinical criteria, we detected among the highest numbers of syndromic CS cases reported, confirmed by a high genetic diagnostic yield of 84%. The observed genetic heterogeneity encourages a broad genetic approach in diagnosing syndromic CS.
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Affiliation(s)
- Elin Tønne
- Faculty of Medicine, University of Oslo, Oslo, Norway.
- Department of Medical Genetics, Oslo University Hospital, Oslo, Norway.
- Norwegian National Unit for Craniofacial Surgery, Oslo University Hospital, Oslo, Norway.
| | - Bernt Johan Due-Tønnessen
- Norwegian National Unit for Craniofacial Surgery, Oslo University Hospital, Oslo, Norway
- Department of Neurosurgery, Oslo University Hospital, Oslo, Norway
| | - Inger-Lise Mero
- Department of Medical Genetics, Oslo University Hospital, Oslo, Norway
| | - Ulrikke Straume Wiig
- Norwegian National Unit for Craniofacial Surgery, Oslo University Hospital, Oslo, Norway
- Department of Neurosurgery, Oslo University Hospital, Oslo, Norway
| | - Mari Ann Kulseth
- Department of Medical Genetics, Oslo University Hospital, Oslo, Norway
| | - Magnus Dehli Vigeland
- Faculty of Medicine, University of Oslo, Oslo, Norway
- Department of Medical Genetics, Oslo University Hospital, Oslo, Norway
| | - Ying Sheng
- Department of Medical Genetics, Oslo University Hospital, Oslo, Norway
| | - Charlotte von der Lippe
- Centre for Rare Disorders, Oslo University Hospital, Rikshospitalet, Oslo, Norway
- Department of Medical Genetics, Telemark Hospital Trust, Skien, Norway
| | - Kristian Tveten
- Department of Medical Genetics, Telemark Hospital Trust, Skien, Norway
| | - Torstein Ragnar Meling
- Faculty of Medicine, University of Oslo, Oslo, Norway
- Department of Neurosurgery, Oslo University Hospital, Oslo, Norway
- Faculty of Medicine, University of Geneva, Geneva, Switzerland
- Department of Neurosurgery, Geneva University Hospitals, Geneva, Switzerland
| | - Eirik Helseth
- Faculty of Medicine, University of Oslo, Oslo, Norway
- Department of Neurosurgery, Oslo University Hospital, Oslo, Norway
| | - Ketil Riddervold Heimdal
- Department of Medical Genetics, Oslo University Hospital, Oslo, Norway
- Norwegian National Unit for Craniofacial Surgery, Oslo University Hospital, Oslo, Norway
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Hu X, He WB, Zhang SP, Luo KL, Gong F, Dai J, Zhang Y, Wan ZX, Li W, Yuan SM, Tan YQ, Lu GX, Lin G, Du J. Next-generation sequence-based preimplantation genetic testing for monogenic disease resulting from maternal mosaicism. Mol Genet Genomic Med 2021; 9:e1662. [PMID: 33942572 PMCID: PMC8172198 DOI: 10.1002/mgg3.1662] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 02/21/2021] [Accepted: 03/01/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Mosaicism poses challenges for genetic counseling and preimplantation genetic testing for monogenic disorders (PGT-M). NGS-based PGT-M has been extensively used to prevent the transmission of monogenic defects, but it has not been evaluated in the application of PGT-M resulting from mosaicism. METHODS Four women suspected of mosaicism were confirmed by ultra-deep sequencing. Blastocyst trophectoderm cells and polar bodies were collected for whole genome amplification, followed by pathogenic variants detection and haplotype analysis based on NGS. The embryos free of the monogenic disorders were transplantable. RESULTS Ultra-deep sequencing confirmed that the four women harbored somatic mosaic variants, with the proportion of variant cells at 1.12%, 9.0%, 27.60%, and 91.03%, respectively. A total of 25 blastocysts were biopsied and detected during four PGT cycles and 5 polar bodies were involved in one cycle additionally. For each couple, a wild-type embryo was successfully transplanted and confirmed by prenatal diagnosis, resulting in the birth of four healthy infants. CONCLUSIONS Mosaic variants could be effectively evaluated via ultra-deep sequencing, and could be prevented the transmission by PGT. Our work suggested that an NGS-based PGT approach, involving pathogenic variants detection combined with haplotype analysis, is crucial for accurate PGT-M with mosaicism.
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Affiliation(s)
- Xiao Hu
- Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, China
| | - Wen-Bin He
- Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, China
| | - Shuo-Ping Zhang
- Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, China.,Institute of Reproduction and Stem Cell Engineering, School of Basic Medical Science, Central South University, Changsha, China
| | - Ke-Li Luo
- Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, China.,Institute of Reproduction and Stem Cell Engineering, School of Basic Medical Science, Central South University, Changsha, China.,Key Laboratory of Stem Cell and Reproduction Engineering, Ministry of Health, Changsha, China
| | - Fei Gong
- Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, China.,Institute of Reproduction and Stem Cell Engineering, School of Basic Medical Science, Central South University, Changsha, China.,Key Laboratory of Stem Cell and Reproduction Engineering, Ministry of Health, Changsha, China
| | - Jing Dai
- Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, China
| | - Yi Zhang
- Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, China
| | - Zhen-Xing Wan
- Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, China
| | - Wen Li
- Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, China.,Institute of Reproduction and Stem Cell Engineering, School of Basic Medical Science, Central South University, Changsha, China.,Key Laboratory of Stem Cell and Reproduction Engineering, Ministry of Health, Changsha, China
| | - Shi-Min Yuan
- Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, China
| | - Yue-Qiu Tan
- Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, China.,Institute of Reproduction and Stem Cell Engineering, School of Basic Medical Science, Central South University, Changsha, China.,Key Laboratory of Stem Cell and Reproduction Engineering, Ministry of Health, Changsha, China
| | - Guang-Xiu Lu
- Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, China.,Key Laboratory of Stem Cell and Reproduction Engineering, Ministry of Health, Changsha, China.,National Engineering and Research Center of Human Stem Cell, Changsha, China
| | - Ge Lin
- Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, China.,Institute of Reproduction and Stem Cell Engineering, School of Basic Medical Science, Central South University, Changsha, China.,Key Laboratory of Stem Cell and Reproduction Engineering, Ministry of Health, Changsha, China.,National Engineering and Research Center of Human Stem Cell, Changsha, China
| | - Juan Du
- Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, China.,Institute of Reproduction and Stem Cell Engineering, School of Basic Medical Science, Central South University, Changsha, China.,Key Laboratory of Stem Cell and Reproduction Engineering, Ministry of Health, Changsha, China
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Matossian M, Warrier R, Kattar N. Concurrent Presentations of Hereditary Spherocytosis and Craniosynostosis Syndromes in Siblings: A Case Series. Clin Pediatr (Phila) 2021; 60:151-153. [PMID: 33480273 DOI: 10.1177/0009922820987110] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
| | - Rajasekharan Warrier
- Ochsner Children's Hospital, New Orleans, LA, USA.,University of Queensland, Herston, Queensland, Australia
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8
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Liu Q, Karolak JA, Grochowski CM, Wilson TA, Rosenfeld JA, Bacino CA, Lalani SR, Patel A, Breman A, Smith JL, Cheung SW, Lupski JR, Bi W, Stankiewicz P. Parental somatic mosaicism for CNV deletions - A need for more sensitive and precise detection methods in clinical diagnostics settings. Genomics 2020; 112:2937-2941. [PMID: 32387503 DOI: 10.1016/j.ygeno.2020.05.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 04/22/2020] [Accepted: 05/04/2020] [Indexed: 10/25/2022]
Abstract
To further assess the scale and level of parental somatic mosaicism, we queried the CMA database at Baylor Genetics. We selected 50 unrelated families where clinically relevant apparent de novo CNV-deletions were found in the affected probands. Parental blood samples screening using deletion junction-specific PCR revealed four parents with somatic mosaicism. Droplet digital PCR (ddPCR), qPCR, and amplicon-based next-generation sequencing (NGS) were applied to validate these findings. Using ddPCR levels of mosaicism ranged from undetectable to 18.5%. Amplicon-based NGS and qPCR for the father with undetectable mosaicism was able to detect mosaicism at 0.39%. In one mother, ddPCR analysis revealed 15.6%, 10.6%, 8.2%, and undetectable levels of mosaicism in her blood, buccal cells, saliva, and urine samples, respectively. Our data suggest that more sensitive and precise methods, e.g. CNV junction-specific LR-PCR, ddPCR, or qPCR may allow for a more refined assessment of the potential disease recurrence risk for an identified variant.
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Affiliation(s)
- Qian Liu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Justyna A Karolak
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Chair and Department of Genetics and Pharmaceutical Microbiology, Poznan University of Medical Sciences, 60-781 Poznan, Poland
| | | | - Theresa A Wilson
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Jill A Rosenfeld
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Baylor Genetics, Houston, TX 77021, USA
| | - Carlos A Bacino
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Baylor Genetics, Houston, TX 77021, USA; Texas Children's Hospital, Houston, TX 77030, USA
| | - Seema R Lalani
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Baylor Genetics, Houston, TX 77021, USA
| | - Ankita Patel
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Baylor Genetics, Houston, TX 77021, USA
| | - Amy Breman
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Baylor Genetics, Houston, TX 77021, USA
| | - Janice L Smith
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Baylor Genetics, Houston, TX 77021, USA
| | - Sau Wai Cheung
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - James R Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA; Texas Children's Hospital, Houston, TX 77030, USA; Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Weimin Bi
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Baylor Genetics, Houston, TX 77021, USA
| | - Pawel Stankiewicz
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA.
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9
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Yilmaz E, Mihci E, Nur B, Alper ÖM, Taçoy Ş. Recent Advances in Craniosynostosis. Pediatr Neurol 2019; 99:7-15. [PMID: 31421914 DOI: 10.1016/j.pediatrneurol.2019.01.018] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 12/25/2018] [Accepted: 01/24/2019] [Indexed: 12/27/2022]
Abstract
Craniosynostosis is a pathologic craniofacial disorder and is defined as the premature fusion of one or more cranial (calvarial) sutures. Cranial sutures are fibrous joints consisting of nonossified mesenchymal cells that play an important role in the development of healthy craniofacial skeletons. Early fusion of these sutures results in incomplete brain development that may lead to complications of several severe medical conditions including seizures, brain damage, mental delay, complex deformities, strabismus, and visual and breathing problems. As a congenital disease, craniosynostosis has a heterogeneous origin that can be affected by genetic and epigenetic alterations, teratogens, and environmental factors and make the syndrome highly complex. To date, approximately 200 syndromes have been linked to craniosynostosis. In addition to being part of a syndrome, craniosynostosis can be nonsyndromic, formed without any additional anomalies. More than 50 nuclear genes that relate to craniosynostosis have been identified. Besides genetic factors, epigenetic factors like microRNAs and mechanical forces also play important roles in suture fusion. As craniosynostosis is a multifactorial disorder, evaluating the craniosynostosis syndrome requires and depends on all the information obtained from clinical findings, genetic analysis, epigenetic or environmental factors, or gene modulators. In this review, we will focus on embryologic and genetic studies, as well as epigenetic and environmental studies. We will discuss published studies and correlate the findings with unknown aspects of craniofacial disorders.
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Affiliation(s)
- Elanur Yilmaz
- Department of Medical Biology and Genetics, Akdeniz University Medical School, Antalya, Turkey
| | - Ercan Mihci
- Department of Pediatric Genetics, Akdeniz University Medical School, Antalya, Turkey
| | - Banu Nur
- Department of Pediatric Genetics, Akdeniz University Medical School, Antalya, Turkey
| | - Özgül M Alper
- Department of Medical Biology and Genetics, Akdeniz University Medical School, Antalya, Turkey.
| | - Şükran Taçoy
- Department of Pediatric Genetics, Akdeniz University Medical School, Antalya, Turkey
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10
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Clinically-relevant postzygotic mosaicism in parents and children with developmental disorders in trio exome sequencing data. Nat Commun 2019; 10:2985. [PMID: 31278258 PMCID: PMC6611863 DOI: 10.1038/s41467-019-11059-2] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 06/12/2019] [Indexed: 12/22/2022] Open
Abstract
Mosaic genetic variants can have major clinical impact. We systematically analyse trio exome sequence data from 4,293 probands from the DDD Study with severe developmental disorders for pathogenic postzygotic mosaicism (PZM) in the child or a clinically-unaffected parent, and use ultrahigh-depth sequencing to validate candidate mosaic variants. We observe that levels of mosaicism for small genetic variants are usually equivalent in both saliva and blood and ~3% of causative de novo mutations exhibit PZM; this is an important observation, as the sibling recurrence risk is extremely low. We identify parental PZM in 21 trios (0.5% of trios), resulting in a substantially increased sibling recurrence risk in future pregnancies. Together, these forms of mosaicism account for 40 (1%) diagnoses in our cohort. Likely child-PZM mutations occur equally on both parental haplotypes, and the penetrance of detectable mosaic pathogenic variants overall is likely to be less than half that of constitutive variants.
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11
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Møller RS, Liebmann N, Larsen LHG, Stiller M, Hentschel J, Kako N, Abdin D, Di Donato N, Pal DK, Zacher P, Syrbe S, Dahl HA, Lemke JR. Parental mosaicism in epilepsies due to alleged de novo variants. Epilepsia 2019; 60:e63-e66. [PMID: 31077350 DOI: 10.1111/epi.15187] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 04/02/2019] [Accepted: 04/15/2019] [Indexed: 02/03/2023]
Abstract
Severe early onset epilepsies are often caused by de novo pathogenic variants. Few studies have reported the frequency of somatic mosaicism in parents of children with severe epileptic encephalopathies. Here we aim to investigate the frequency of mosaicism in the parents of children with epilepsy caused by alleged de novo variants. We tested parental genomic DNA derived from different tissues for 75 cases using targeted next-generation sequencing. Five parents (6.6%) showed mosaicism at minor allele frequencies of 0.8%-29% for the pathogenic variant detected in their offspring. Parental mosaicism was observed in the following genes: SCN1A, SCN2A, SCN8A, and STXBP1. One of the identified parents had epilepsy himself. Our results show that de novo events can occur already in parental tissue and in some cases can be detected in peripheral blood. Consequently, parents affected by low-grade mosaicism are faced with an increased recurrence risk for transmitting the pathogenic variant, compared to the overall recurrence risk for a second affected child estimated at approximately 1%. However, testing for parental somatic mosaicism will help identifying those parents who truly are at higher risk and will significantly improve genetic counseling in the respective families.
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Affiliation(s)
- Rikke S Møller
- Danish Epilepsy Centre, Dianalund, Denmark
- Institute of Regional Health Research, University of Southern Denmark, Odense, Denmark
| | - Nora Liebmann
- Institute of Human Genetics, University of Leipzig Medical Center, Leipzig, Germany
| | | | - Mathias Stiller
- Institute of Human Genetics, University of Leipzig Medical Center, Leipzig, Germany
| | - Julia Hentschel
- Institute of Human Genetics, University of Leipzig Medical Center, Leipzig, Germany
| | | | - Dalia Abdin
- Institute for Clinical Genetics, TU Dresden, Dresden, Germany
| | | | - Deb K Pal
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
- MRC Centre for Neurodevelopmental Disorders, King's College London, London, UK
- King's College Hospital, London, UK
- Evelina London Children's Hospital, London, UK
| | - Pia Zacher
- The Saxon Epilepsy Center Kleinwachau, Radeberg, Germany
| | - Steffen Syrbe
- Department of General Paediatrics, Division of Child Neurology and Inherited Metabolic Diseases, Centre for Paediatrics and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | | | - Johannes R Lemke
- Institute of Human Genetics, University of Leipzig Medical Center, Leipzig, Germany
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12
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Sewda A, White SR, Erazo M, Hao K, García-Fructuoso G, Fernández-Rodriguez I, Heuzé Y, Richtsmeier JT, Romitti PA, Reva B, Jabs EW, Peter I. Nonsyndromic craniosynostosis: novel coding variants. Pediatr Res 2019; 85:463-468. [PMID: 30651579 PMCID: PMC6398438 DOI: 10.1038/s41390-019-0274-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Accepted: 11/09/2018] [Indexed: 11/10/2022]
Abstract
BACKGROUND Craniosynostosis (CS), the premature fusion of one or more neurocranial sutures, is associated with approximately 200 syndromes; however, about 65-85% of patients present with no additional major birth defects. METHODS We conducted targeted next-generation sequencing of 60 known syndromic and other candidate genes in patients with sagittal nonsyndromic CS (sNCS, n = 40) and coronal nonsyndromic CS (cNCS, n = 19). RESULTS We identified 18 previously published and 5 novel pathogenic variants, including three de novo variants. Novel variants included a paternally inherited c.2209C>G:p.(Leu737Val) variant in BBS9 of a patient with cNCS. Common variants in BBS9, a gene required for ciliogenesis during cranial suture development, have been associated with sNCS risk in a previous genome-wide association study. We also identified c.313G>T:p.(Glu105*) variant in EFNB1 and c.435G>C:p.(Lys145Asn) variant in TWIST1, both in patients with cNCS. Mutations in EFNB1 and TWIST1 have been linked to craniofrontonasal and Saethre-Chotzen syndrome, respectively; both present with coronal CS. CONCLUSIONS We provide additional evidence that variants in genes implicated in syndromic CS play a role in isolated CS, supporting their inclusion in genetic panels for screening patients with NCS. We also identified a novel BBS9 variant that further shows the potential involvement of BBS9 in the pathogenesis of CS.
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Affiliation(s)
- Anshuman Sewda
- Department of Genetics & Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
| | - Sierra R. White
- Department of Genetics & Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Monica Erazo
- Department of Genetics & Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Ke Hao
- Department of Genetics & Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, New York
| | | | | | - Yann Heuzé
- University Bordeaux, CNRS, MCC, PACEA, UMR5199, Bordeaux Archaeological Sciences Cluster of Excellence, Pessac, France
| | - Joan T. Richtsmeier
- Department of Anthropology, Pennsylvania State University, University Park, Pennsylvania
| | - Paul A. Romitti
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, Iowa
| | - Boris Reva
- Department of Genetics & Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Ethylin Wang Jabs
- Department of Genetics & Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Inga Peter
- Department of Genetics & Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, New York
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13
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Craniosynostosis as a clinical and diagnostic problem: molecular pathology and genetic counseling. J Appl Genet 2018; 59:133-147. [PMID: 29392564 DOI: 10.1007/s13353-017-0423-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2017] [Revised: 12/11/2017] [Accepted: 12/20/2017] [Indexed: 12/16/2022]
Abstract
Craniosynostosis (occurrence: 1/2500 live births) is a result of premature fusion of cranial sutures, leading to alterations of the pattern of cranial growth, resulting in abnormal shape of the head and dysmorphic facial features. In approximately 85% of cases, the disease is isolated and nonsyndromic and mainly involves only one suture. Syndromic craniosynostoses such as Crouzon, Apert, Pfeiffer, Muenke, and Saethre-Chotzen syndromes not only affect multiple sutures, but are also associated with the presence of additional clinical symptoms, including hand and feet malformations, skeletal and cardiac defects, developmental delay, and others. The etiology of craniosynostoses may involve genetic (also somatic mosaicism and regulatory mutations) and epigenetic factors, as well as environmental factors. According to the published data, chromosomal aberrations, mostly submicroscopic ones, account for about 6.7-40% of cases of syndromic craniosynostoses presenting with premature fusion of metopic or sagittal sutures. The best characterized is the deletion or translocation of the 7p21 region containing the TWIST1 gene. The deletions of 9p22 or 11q23-qter (Jacobsen syndrome) are both associated with trigonocephaly. The genes related to the pathogenesis of the craniosynostoses itself are those encoding transcription factors, e.g., TWIST1, MSX2, EN1, and ZIC1, and proteins involved in osteogenic proliferation, differentiation, and homeostasis, such as FGFR1, FGFR2, RUNX2, POR, and many others. In this review, we present the clinical and molecular features of selected craniosynostosis syndromes, genotype-phenotype correlation, family genetic counseling, and propose the most appropriate diagnostic algorithm.
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14
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Wilkie AOM, Goriely A. Gonadal mosaicism and non-invasive prenatal diagnosis for 'reassurance' in sporadic paternal age effect (PAE) disorders. Prenat Diagn 2017; 37:946-948. [PMID: 28686291 PMCID: PMC5638092 DOI: 10.1002/pd.5108] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 06/25/2017] [Accepted: 07/01/2017] [Indexed: 12/20/2022]
Affiliation(s)
- Andrew O M Wilkie
- Clinical Genetics Group, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Anne Goriely
- Clinical Genetics Group, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
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15
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Li J, Li S. The Phenotypes of Spheno-Occipital Synchondrosis in Patients With Crouzon Syndrome. J Craniofac Surg 2016; 27:1244-6. [DOI: 10.1097/scs.0000000000002732] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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16
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Somatic mosaicism: implications for disease and transmission genetics. Trends Genet 2015; 31:382-92. [PMID: 25910407 DOI: 10.1016/j.tig.2015.03.013] [Citation(s) in RCA: 190] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Revised: 03/17/2015] [Accepted: 03/18/2015] [Indexed: 11/21/2022]
Abstract
Nearly all of the genetic material among cells within an organism is identical. However, single-nucleotide variants (SNVs), small insertions/deletions (indels), copy-number variants (CNVs), and other structural variants (SVs) continually accumulate as cells divide during development. This process results in an organism composed of countless cells, each with its own unique personal genome. Thus, every human is undoubtedly mosaic. Mosaic mutations can go unnoticed, underlie genetic disease or normal human variation, and may be transmitted to the next generation as constitutional variants. We review the influence of the developmental timing of mutations, the mechanisms by which they arise, methods for detecting mosaic variants, and the risk of passing these mutations on to the next generation.
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17
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Huang AY, Xu X, Ye AY, Wu Q, Yan L, Zhao B, Yang X, He Y, Wang S, Zhang Z, Gu B, Zhao HQ, Wang M, Gao H, Gao G, Zhang Z, Yang X, Wu X, Zhang Y, Wei L. Postzygotic single-nucleotide mosaicisms in whole-genome sequences of clinically unremarkable individuals. Cell Res 2014; 24:1311-27. [PMID: 25312340 PMCID: PMC4220156 DOI: 10.1038/cr.2014.131] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Revised: 07/03/2014] [Accepted: 09/11/2014] [Indexed: 12/29/2022] Open
Abstract
Postzygotic single-nucleotide mutations (pSNMs) have been studied in cancer and a few other overgrowth human disorders at whole-genome scale and found to play critical roles. However, in clinically unremarkable individuals, pSNMs have never been identified at whole-genome scale largely due to technical difficulties and lack of matched control tissue samples, and thus the genome-wide characteristics of pSNMs remain unknown. We developed a new Bayesian-based mosaic genotyper and a series of effective error filters, using which we were able to identify 17 SNM sites from ∼80× whole-genome sequencing of peripheral blood DNAs from three clinically unremarkable adults. The pSNMs were thoroughly validated using pyrosequencing, Sanger sequencing of individual cloned fragments, and multiplex ligation-dependent probe amplification. The mutant allele fraction ranged from 5%-31%. We found that C→T and C→A were the predominant types of postzygotic mutations, similar to the somatic mutation profile in tumor tissues. Simulation data showed that the overall mutation rate was an order of magnitude lower than that in cancer. We detected varied allele fractions of the pSNMs among multiple samples obtained from the same individuals, including blood, saliva, hair follicle, buccal mucosa, urine, and semen samples, indicating that pSNMs could affect multiple sources of somatic cells as well as germ cells. Two of the adults have children who were diagnosed with Dravet syndrome. We identified two non-synonymous pSNMs in SCN1A, a causal gene for Dravet syndrome, from these two unrelated adults and found that the mutant alleles were transmitted to their children, highlighting the clinical importance of detecting pSNMs in genetic counseling.
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Affiliation(s)
- August Y Huang
- 1] National Institute of Biological Sciences, Beijing 102206, China [2] Center for Bioinformatics, State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China
| | - Xiaojing Xu
- Peking University First Hospital, Peking University, Beijing 100034, China
| | - Adam Y Ye
- 1] Center for Bioinformatics, State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China [2] Peking-Tsinghua Center for Life Sciences, Beijing 100871, China [3] Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Qixi Wu
- National Institute of Biological Sciences, Beijing 102206, China
| | - Linlin Yan
- Center for Bioinformatics, State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China
| | - Boxun Zhao
- 1] National Institute of Biological Sciences, Beijing 102206, China [2] Graduate School of Peking Union Medical College, Beijing 100730, China
| | - Xiaoxu Yang
- Center for Bioinformatics, State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China
| | - Yao He
- 1] National Institute of Biological Sciences, Beijing 102206, China [2] Center for Bioinformatics, State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China [3] Peking-Tsinghua Center for Life Sciences, Beijing 100871, China [4] Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Sheng Wang
- National Institute of Biological Sciences, Beijing 102206, China
| | - Zheng Zhang
- 1] National Institute of Biological Sciences, Beijing 102206, China [2] Center for Bioinformatics, State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China [3] Peking-Tsinghua Center for Life Sciences, Beijing 100871, China [4] Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Bowen Gu
- National Institute of Biological Sciences, Beijing 102206, China
| | - Han-Qing Zhao
- Center for Bioinformatics, State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China
| | - Meng Wang
- Center for Bioinformatics, State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China
| | - Hua Gao
- Center for Bioinformatics, State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China
| | - Ge Gao
- Center for Bioinformatics, State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China
| | - Zhichao Zhang
- Peking University First Hospital, Peking University, Beijing 100034, China
| | - Xiaoling Yang
- Peking University First Hospital, Peking University, Beijing 100034, China
| | - Xiru Wu
- Peking University First Hospital, Peking University, Beijing 100034, China
| | - Yuehua Zhang
- Peking University First Hospital, Peking University, Beijing 100034, China
| | - Liping Wei
- 1] National Institute of Biological Sciences, Beijing 102206, China [2] Center for Bioinformatics, State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China
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Müller CM, Haase MG, Kemnitz I, Fitze G. Genetic mosaicism of a frameshift mutation in the RET gene in a family with Hirschsprung disease. Gene 2014; 541:51-4. [DOI: 10.1016/j.gene.2014.02.027] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Accepted: 02/14/2014] [Indexed: 12/26/2022]
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Li X, Young NM, Tropp S, Hu D, Xu Y, Hallgrímsson B, Marcucio RS. Quantification of shape and cell polarity reveals a novel mechanism underlying malformations resulting from related FGF mutations during facial morphogenesis. Hum Mol Genet 2013; 22:5160-72. [PMID: 23906837 DOI: 10.1093/hmg/ddt369] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Fibroblast growth factor (FGF) signaling mutations are a frequent contributor to craniofacial malformations including midfacial anomalies and craniosynostosis. FGF signaling has been shown to control cellular mechanisms that contribute to facial morphogenesis and growth such as proliferation, survival, migration and differentiation. We hypothesized that FGF signaling not only controls the magnitude of growth during facial morphogenesis but also regulates the direction of growth via cell polarity. To test this idea, we infected migrating neural crest cells of chicken embryos with replication-competent avian sarcoma virus expressing either FgfR2(C278F), a receptor mutation found in Crouzon syndrome or the ligand Fgf8. Treated embryos exhibited craniofacial malformations resembling facial dysmorphologies in craniosynostosis syndrome. Consistent with our hypothesis, ectopic activation of FGF signaling resulted in decreased cell proliferation, increased expression of the Sprouty class of FGF signaling inhibitors, and repressed phosphorylation of ERK/MAPK. Furthermore, quantification of cell polarity in facial mesenchymal cells showed that while orientation of the Golgi body matches the direction of facial prominence outgrowth in normal cells, in FGF-treated embryos this direction is randomized, consistent with aberrant growth that we observed. Together, these data demonstrate that FGF signaling regulates cell proliferation and cell polarity and that these cell processes contribute to facial morphogenesis.
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Affiliation(s)
- Xin Li
- Department of Orthopedic Surgery, Orthopedic Trauma Institute, San Francisco General Hospital, University of California, San Francisco, CA, USA
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Ahmed Z, Lin CC, Suen KM, Melo FA, Levitt JA, Suhling K, Ladbury JE. Grb2 controls phosphorylation of FGFR2 by inhibiting receptor kinase and Shp2 phosphatase activity. ACTA ACUST UNITED AC 2013; 200:493-504. [PMID: 23420874 PMCID: PMC3575544 DOI: 10.1083/jcb.201204106] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Constitutive receptor tyrosine kinase phosphorylation requires regulation of kinase and phosphatase activity to prevent aberrant signal transduction. A dynamic mechanism is described here in which the adaptor protein, growth factor receptor-bound protein 2 (Grb2), controls fibroblast growth factor receptor 2 (FGFR2) signaling by regulating receptor kinase and SH2 domain-containing protein tyrosine phosphatase 2 (Shp2) phosphatase activity in the absence of extracellular stimulation. FGFR2 cycles between its kinase-active, partially phosphorylated, nonsignaling state and its Shp2-dephosphorylated state. Concurrently, Shp2 cycles between its FGFR2-phosphorylated and dephosphorylated forms. Both reciprocal activities of FGFR2 and Shp2 were inhibited by binding of Grb2 to the receptor. Phosphorylation of Grb2 by FGFR2 abrogated its binding to the receptor, resulting in up-regulation of both FGFR2's kinase and Shp2's phosphatase activity. Dephosphorylation of Grb2 by Shp2 rescued the FGFR2-Grb2 complex. This cycling of enzymatic activity results in a homeostatic, signaling-incompetent state. Growth factor binding perturbs this background cycling, promoting increased FGFR2 phosphorylation and kinase activity, Grb2 dissociation, and downstream signaling. Grb2 therefore exerts constitutive control over the mutually dependent activities of FGFR2 and Shp2.
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Affiliation(s)
- Zamal Ahmed
- Department of Biochemistry and Molecular Biology and Center for Biomolecular Structure and Function, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
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Abstract
Birth rates for older fathers have increased 30% since 1980. When combined with the increased risk for genetic and multifactorial disorders in children conceived by older fathers, paternal age has become an important health issue for modern society. Laboratory research in this area has been minimal, perhaps because of significant experimental barriers, not the least of which is inadequate access to fresh, disease-free human testicular tissue. Regardless, progress has been made and intriguing models supported by experimental evidence have been proposed. The putative mechanisms range from reduced DNA repair activity, leading to increased mutagenesis, to positive selection of germ cells harboring specific disease-causing mutations. There remain many important venues for research in this increasingly relevant phenomenon that impacts future generations.
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Affiliation(s)
- Jamila R Momand
- South Texas Veterans Health Care System, San Antonio, TX 78229-3900, USA
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Jay S, Wiberg A, Swan M, Lester T, Williams LJ, Taylor IB, Johnson D, Wilkie AOM. The fibroblast growth factor receptor 2 p.Ala172Phe mutation in Pfeiffer syndrome--history repeating itself. Am J Med Genet A 2013; 161A:1158-63. [PMID: 23532954 PMCID: PMC3652025 DOI: 10.1002/ajmg.a.35842] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2012] [Accepted: 10/16/2012] [Indexed: 11/09/2022]
Abstract
Pfeiffer syndrome is an autosomal dominant condition classically combining craniosynostosis with digital anomalies of the hands and feet. The majority of cases are caused by heterozygous mutations in the third immunoglobulin-like domain (IgIII) of FGFR2, whilst a small number of cases can be attributed to mutations outside this region of the protein. A mild form of Pfeiffer syndrome can rarely be caused by a specific mutation in FGFR1. We report on the clinical and genetic findings in a three generation British family with Pfeiffer syndrome caused by a heterozygous missense mutation, p.Ala172Phe, located in the IgII domain of FGFR2. This is the first reported case of this particular mutation since Pfeiffer's index case, originally described in a German family in 1964, on which basis the syndrome was eponymously named. Genetic analysis demonstrated the two families to be unrelated. Similarities in phenotypes between the two families are discussed. Independent genetic origins, but phenotypic similarities in the two families add to the evidence supporting the theory of selfish spermatogonial selective advantage for this rare gain-of-function FGFR2 mutation. © 2013 Wiley Periodicals, Inc.
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Affiliation(s)
- Sally Jay
- Department of Plastic Surgery, John Radcliffe Hospital, Oxford, UK
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Vidal Sanahuja R, Gean Molins E, Sánchez Garré C, Quilis Esquerra J, García Fructuoso G, Costa Clara JM. [Presentation of two cases of Crouzon syndrome: allelic cranio-stenotic conditions of FGFR genes]. An Pediatr (Barc) 2012; 77:272-8. [PMID: 22633821 DOI: 10.1016/j.anpedi.2012.03.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Revised: 03/24/2012] [Accepted: 03/28/2012] [Indexed: 11/17/2022] Open
Abstract
INTRODUCTION Craniosynostosis is an abnormal and premature fusion of any cranial suture. Twenty per cent of them involve any specific syndrome with Mendelian transmission; the other 80% are "non syndromic", although but 10-14% of them are genetically transmitted. Using the experience of two patients with Crouzon syndrome, a clinical and genetic review is performed. PATIENTS AND METHODS Patient 1: girl of 35 days of age with progressive macrocephaly, protrusion of fontanel, ocular proptosis, hypertelorism and divergent strabismus. Cranial RX with sagittal synostosis. Surgical operation was performed with 3 months and 8 months of age due to development of pansynostosis. Patient 2: boy of 3 years 8 months of age with headaches of migrainous type of one year onset. He had acanthosis nigricans. Cranial RX and cerebral CT with evident digital markings and fundus of eye with undefined papillary limits, but 18 month later oedematous papilla were evident and pansynostosis was detected, so surgery was performed. RESULTS We present a patient with classical Crouzon syndrome (patient 1) and another with acanthosis nigricans (patient 2), both diagnosed by the description of characteristic clinical features. CONCLUSIONS Ten craniosynostotic clinical forms are currently known as allelic variations of the FGFR genes, and as such have reviewed them. As in our two cases, in syndromic types is very important the accurate study of the phenotype to orientate the diagnosis, although the molecular study will confirm it in many patients and genetic counselling offered.
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Affiliation(s)
- R Vidal Sanahuja
- Unitat de Neuropediatria, Servei de Pediatria, Consorci Sanitari de Terrassa, Terrassa, Barcelona, España.
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Paternal age effect mutations and selfish spermatogonial selection: causes and consequences for human disease. Am J Hum Genet 2012; 90:175-200. [PMID: 22325359 DOI: 10.1016/j.ajhg.2011.12.017] [Citation(s) in RCA: 247] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Revised: 12/05/2011] [Accepted: 12/26/2011] [Indexed: 12/25/2022] Open
Abstract
Advanced paternal age has been associated with an increased risk for spontaneous congenital disorders and common complex diseases (such as some cancers, schizophrenia, and autism), but the mechanisms that mediate this effect have been poorly understood. A small group of disorders, including Apert syndrome (caused by FGFR2 mutations), achondroplasia, and thanatophoric dysplasia (FGFR3), and Costello syndrome (HRAS), which we collectively term "paternal age effect" (PAE) disorders, provides a good model to study the biological and molecular basis of this phenomenon. Recent evidence from direct quantification of PAE mutations in sperm and testes suggests that the common factor in the paternal age effect lies in the dysregulation of spermatogonial cell behavior, an effect mediated molecularly through the growth factor receptor-RAS signal transduction pathway. The data show that PAE mutations, although arising rarely, are positively selected and expand clonally in normal testes through a process akin to oncogenesis. This clonal expansion, which is likely to take place in the testes of all men, leads to the relative enrichment of mutant sperm over time-explaining the observed paternal age effect associated with these disorders-and in rare cases to the formation of testicular tumors. As regulation of RAS and other mediators of cellular proliferation and survival is important in many different biological contexts, for example during tumorigenesis, organ homeostasis and neurogenesis, the consequences of selfish mutations that hijack this process within the testis are likely to extend far beyond congenital skeletal disorders to include complex diseases, such as neurocognitive disorders and cancer predisposition.
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Di Rocco F, Collet C, Legeai-Mallet L, Arnaud E, Le Merrer M, Hadj-Rabia S, Renier D. Crouzon syndrome with acanthosis nigricans: a case-based update. Childs Nerv Syst 2011; 27:349-54. [PMID: 21136065 DOI: 10.1007/s00381-010-1347-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2010] [Accepted: 11/14/2010] [Indexed: 10/18/2022]
Abstract
BACKGROUND Crouzon syndrome with acanthosis nigricans also named Crouzono-dermo-skeletal is a clinically and genetically distinct entity. It associates a craniofacial phenotype to anomalies of the skin and long bones. This syndrome is due to a specific mutation in FGFR3 gene that can be identified by genetic testing. ILLUSTRATIVE CASES As in our two patients, not all these features might be present and some will be patent only in the infancy or early childhood. Moreover, other organs such as the kidneys might be affected. DISCUSSION Because several organs might be affected the recognition of such syndrome is important for a correct management of the patient as well as a proper information and genetic counseling of the families.
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Affiliation(s)
- Federico Di Rocco
- Unité de Chirurgie Craniofaciale, Neurochirurgie Pédiatrique Hôpital Necker Enfants Malades, Centre de Référence Maladies rares Dysostoses Craniofaciales, 149 rue de Sèvres, 75015 Paris, France.
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Abstract
Craniosynostosis, defined as the premature fusion of the cranial sutures, presents many challenges in classification and treatment. At least 20% of cases are caused by specific single gene mutations or chromosome abnormalities. This article maps out approaches to clinical assessment of a child presenting with an unusual head shape, and illustrates how genetic analysis can contribute to diagnosis and management.
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Affiliation(s)
- David Johnson
- Oxford Craniofacial Unit, Oxford Radcliffe Hospitals NHS Trust, John Radcliffe Hospital, Oxford, UK
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