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Bai T, Shen Y, Yang Y, Dai S, Liu H. Maternal CHD7 gonosomal mosaicism in a fetus with CHARGE syndrome. Am J Med Genet A 2024; 194:e63491. [PMID: 38057991 DOI: 10.1002/ajmg.a.63491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 11/16/2023] [Accepted: 11/20/2023] [Indexed: 12/08/2023]
Abstract
Parental mosaicism is important in families with de novo mutations. Herein, we report a case of fetal CHARGE syndrome (CS) with a CHD7 variant inherited from maternal CHD7 gonosomal mosaicism. The variant was detected through trio-based whole-exome sequencing and Sanger sequencing. High-depth whole-exome sequencing was performed for the identification of parental mosaicism. A novel heterozygous CHD7 nonsense mutation (c.5794G>T/ p.E1932*) was detected in the tissue from the aborted fetus. The parents were wild-type, indicating that the mutation was a de novo variant. The mutation was suspected to be the cause of the fetal CS. However, high-depth whole-exome sequencing revealed maternal gonosomal mosaicism at a variant allele frequency of 3.2%-23.3%. The variant was identified in various tissues (peripheral blood, hair follicles, buccal epithelia, and pharyngeal epithelia) from the asymptomatic mother. We confirmed maternal CHD7 gonosomal mosaicism as a genetic cause of fetal CS. Our results emphasize the importance of clinical analysis in accurately determining the parents' status in detecting the CHD7 de novo variant in fetal CS, as this analysis has vital implications for evaluating the recurrence risk for genetic counseling.
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Affiliation(s)
- Ting Bai
- Department of Medical Genetics, West China Second University Hospital, Sichuan University, Chengdu, China
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Sichuan University, Ministry of Education, Chengdu, China
- Department of Obstetrics and Gynecology, West China Second University Hospital, Sichuan University, Chengdu, China
| | - Ying Shen
- Department of Obstetrics/Gynecology, Joint Laboratory of Reproductive Medicine (SCU-CUHK), Key Laboratory of Obstetric, Gynecologic and Pediatric Diseases and Birth Defects of Ministry of Education, West China Second University Hospital, Sichuan University, Chengdu, China
| | - Yanting Yang
- Department of Medical Genetics, West China Second University Hospital, Sichuan University, Chengdu, China
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Sichuan University, Ministry of Education, Chengdu, China
| | - Siyu Dai
- Department of Obstetrics and Gynecology, West China Second University Hospital, Sichuan University, Chengdu, China
| | - Hongqian Liu
- Department of Medical Genetics, West China Second University Hospital, Sichuan University, Chengdu, China
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Sichuan University, Ministry of Education, Chengdu, China
- Department of Obstetrics and Gynecology, West China Second University Hospital, Sichuan University, Chengdu, China
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2
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Roux I, Fenollar-Ferrer C, Lee HJ, Chattaraj P, Lopez IA, Han K, Honda K, Brewer CC, Butman JA, Morell RJ, Martin DM, Griffith AJ. CHD7 variants associated with hearing loss and enlargement of the vestibular aqueduct. Hum Genet 2023; 142:1499-1517. [PMID: 37668839 PMCID: PMC10511616 DOI: 10.1007/s00439-023-02581-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Accepted: 06/20/2023] [Indexed: 09/06/2023]
Abstract
Enlargement of the endolymphatic sac, duct, and vestibular aqueduct (EVA) is the most common inner ear malformation identified in patients with sensorineural hearing loss. EVA is associated with pathogenic variants in SLC26A4. However, in European-Caucasian populations, about 50% of patients with EVA carry no pathogenic alleles of SLC26A4. We tested for the presence of variants in CHD7, a gene known to be associated with CHARGE syndrome, Kallmann syndrome, and hypogonadotropic hypogonadism, in a cohort of 34 families with EVA subjects without pathogenic alleles of SLC26A4. In two families, NM_017780.4: c.3553A > G [p.(Met1185Val)] and c.5390G > C [p.(Gly1797Ala)] were detected as monoallelic CHD7 variants in patients with EVA. At least one subject from each family had additional signs or potential signs of CHARGE syndrome but did not meet diagnostic criteria for CHARGE. In silico modeling of these two missense substitutions predicted detrimental effects upon CHD7 protein structure. Consistent with a role of CHD7 in this tissue, Chd7 transcript and protein were detected in all epithelial cells of the endolymphatic duct and sac of the developing mouse inner ear. These results suggest that some CHD7 variants can cause nonsyndromic hearing loss and EVA. CHD7 should be included in DNA sequence analyses to detect pathogenic variants in EVA patients. Chd7 expression and mutant phenotype data in mice suggest that CHD7 contributes to the formation or function of the endolymphatic sac and duct.
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Affiliation(s)
- Isabelle Roux
- Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders (NIDCD), National Institutes of Health (NIH), Bethesda, MD, 20892, USA.
| | - Cristina Fenollar-Ferrer
- Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders (NIDCD), National Institutes of Health (NIH), Bethesda, MD, 20892, USA
- Laboratory of Molecular Genetics, NIDCD, NIH, Bethesda, MD, 20892, USA
| | - Hyun Jae Lee
- Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders (NIDCD), National Institutes of Health (NIH), Bethesda, MD, 20892, USA
| | - Parna Chattaraj
- Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders (NIDCD), National Institutes of Health (NIH), Bethesda, MD, 20892, USA
| | - Ivan A Lopez
- The NIDCD National Temporal Laboratory at UCLA, Department of Head and Neck Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA, 90095, USA
| | - Kyungreem Han
- Laboratory of Membrane Biophysics, NHLBI, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Keiji Honda
- Department of Otorhinolaryngology, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan
| | - Carmen C Brewer
- Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders (NIDCD), National Institutes of Health (NIH), Bethesda, MD, 20892, USA
| | - John A Butman
- Radiology and Imaging Sciences, Clinical Center, NIH, Bethesda, MD, 20892, USA
| | - Robert J Morell
- Genomics and Computational Biology Core, NIDCD, NIH, Bethesda, MD, 20892, USA
| | - Donna M Martin
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI, USA
- Department of Pediatrics, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Andrew J Griffith
- Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders (NIDCD), National Institutes of Health (NIH), Bethesda, MD, 20892, USA
- Department of Otolaryngology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN, 38163, USA
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3
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Breuss MW, Yang X, Gleeson JG. Sperm mosaicism: implications for genomic diversity and disease. Trends Genet 2021; 37:890-902. [PMID: 34158173 PMCID: PMC9484299 DOI: 10.1016/j.tig.2021.05.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 05/26/2021] [Accepted: 05/27/2021] [Indexed: 12/18/2022]
Abstract
While sperm mosaicism has few consequences for men, the offspring and future generations are unwitting recipients of gonadal cell mutations, often yielding severe disease. Recent studies, fueled by emergent technologies, show that sperm mosaicism is a common source of de novo mutations (DNMs) that underlie severe pediatric disease as well as human genetic diversity. Sperm mosaicism can be divided into three types: Type I arises during sperm meiosis and is non-age dependent; Type II arises in spermatogonia and increases as men age; and Type III arises during paternal embryogenesis, spreads throughout the body, and contributes stably to sperm throughout life. Where Types I and II confer little risk of recurrence, Type III may confer identifiable risk to future offspring. These mutations are likely to be the single largest contributor to human genetic diversity. New sequencing approaches may leverage this framework to evaluate and reduce disease risk for future generations.
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Affiliation(s)
- Martin W Breuss
- Department of Pediatrics, Section of Genetics and Metabolism, University of Colorado School of Medicine, Aurora, CO, USA
| | - Xiaoxu Yang
- Rady Children's Institute for Genomic Medicine, Department of Neurosciences, University of California, San Diego, CA, USA
| | - Joseph G Gleeson
- Rady Children's Institute for Genomic Medicine, Department of Neurosciences, University of California, San Diego, CA, USA.
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Pan N, Chen S, Cai X, Li J, Yu T, Huang HF, Zhang J, Xu C. Low-level germline mosaicism of a novel SMARCA2 missense variant: Expanding the phenotypic spectrum and mode of genetic transmission. Mol Genet Genomic Med 2021; 9:e1763. [PMID: 34296532 PMCID: PMC8457699 DOI: 10.1002/mgg3.1763] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 07/06/2021] [Accepted: 07/08/2021] [Indexed: 12/02/2022] Open
Abstract
Background Nicolaides–Baraitser syndrome (NCBRS) is a severe neurodevelopmental disorder with multiple abnormalities. To date, all pathogenic variants in SMARCA2 causing NCBRS are de novo and most are missense variants located in the ATPase domain of SMARCA2 protein. Methods In this study, a familial trio whole‐exome sequencing was performed on the proband presenting with intellectual disability, early‐onset epilepsy, and autistic features. A novel missense variant c.553C>G (p.Gln185Glu) in SMARCA2 was identified, which is located in the QLQ domain. The same variant was subsequently also found in the mother's ongoing pregnancy. Samples from accessible tissues such as saliva and sperm other than blood were collected from the parents, and the detection of the target variant was performed by amplicon‐based deep sequencing. Results Low‐level mosaicism of the target variant c.553C>G (p.Gln185Glu) was detected in the father's sperm with allele fraction of 2.8% by amplicon‐based deep sequencing, which was not detected in either parents’ blood or saliva specimens. Heterozygosity of this variant was confirmed in the proband. Conclusion This is the first report of paternal germline mosaicism for a SMARCA2 disease‐causing variant. In addition, the missense variant c.553C>G (p.Gln185Glu) in the QLQ domain causes mainly neurological and developmental phenotypes with unremarkable characteristic facial features and limb abnormalities. Our findings expand the phenotypic spectrum and mode of genetic transmission associated with the SMARCA2 variants.
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Affiliation(s)
- Nina Pan
- International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.,Shanghai Key Laboratory of Embryo Original Diseases, Shanghai, China
| | - Songchang Chen
- Obstetrics and Gynecology Hospital, Institute of Reproduction and Development, Fudan University, Shanghai, China.,State Key Laboratory of Genetic Engineering and MOE Engineering Research Center of Gene Technology, School of Life Sciences, Fudan University, Shanghai, China
| | - Xiaoqiang Cai
- Beijing BioBiggen Technology Co., Ltd.,, Beijing, China
| | - Jianli Li
- Beijing BioBiggen Technology Co., Ltd.,, Beijing, China
| | - Tao Yu
- Beijing BioBiggen Technology Co., Ltd.,, Beijing, China
| | - He-Feng Huang
- International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.,Shanghai Key Laboratory of Embryo Original Diseases, Shanghai, China.,Obstetrics and Gynecology Hospital, Institute of Reproduction and Development, Fudan University, Shanghai, China.,Clinical Research Center for Birth Defects and Rare Diseases, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.,Key Laboratory of Reproductive Genetics, Ministry of Education, Zhejiang University, Hangzhou, China.,Women's Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Jinglan Zhang
- Obstetrics and Gynecology Hospital, Institute of Reproduction and Development, Fudan University, Shanghai, China.,Beijing BioBiggen Technology Co., Ltd.,, Beijing, China.,Clinical Research Center for Birth Defects and Rare Diseases, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Chenming Xu
- Shanghai Key Laboratory of Embryo Original Diseases, Shanghai, China.,Obstetrics and Gynecology Hospital, Institute of Reproduction and Development, Fudan University, Shanghai, China
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5
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Gug C, Gorduza EV, Lăcătuşu A, Vaida MA, Bîrsăşteanu F, Puiu M, Stoicănescu D. CHARGE syndrome associated with de novo (I1460Rfs *15) frameshift mutation of CHD7 gene in a patient with arteria lusoria and horseshoe kidney. Exp Ther Med 2020; 20:479-485. [PMID: 32509017 PMCID: PMC7271729 DOI: 10.3892/etm.2020.8683] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 03/02/2020] [Indexed: 12/22/2022] Open
Abstract
CHARGE syndrome is an autosomal dominant condition caused by mutations in the chromodomain helicase DNA binding protein 7 (CHD7) gene. The present study reported on the case of a 16-month-old female with plurimalformative syndrome, whose etiology was identified by clinical whole-exome sequencing (WES) analysis. Clinical and follow-up assessments identified multiple craniofacial dysmorphisms, congenital defects and functional symptoms, including dysphagia and Marcus Gunn jaw winking synkinesis. Trio-WES analysis was performed for the patient and their parents and the presence of CHARGE syndrome was further indicated using single-molecule real-time sequencing. A de novo pathogenic variant, c.4379_4380del (p.Ile1460Argfs*15), was identified in exon 19 of the CHD7 gene, which resulted in a premature translational stop signal. Trio-WES analysis was used for further investigation, indicating that neither of the patient's parents had the mutation and confirming its de novo nature. To the best of our knowledge, the case of the present study was the first reported case of CHARGE syndrome in Romania with congenital defects including an aberrant right subclavian artery and a horseshoe kidney. CHARGE syndrome was diagnosed in the patient based on the pathogenic mutation in the CHD7 gene. To the best of our knowledge, the present case report is the first to suggest that the CHD7 gene variant is associated with CHARGE syndrome.
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Affiliation(s)
- Cristina Gug
- Department of Microscopic Morphology, Victor Babeş University of Medicine and Pharmacy, 300041 Timisoara, Romania
| | - Eusebiu Vlad Gorduza
- Prenatal Diagnosis Department, Cuza Voda Obstetrics-Gynecology Clinical Hospital, 700038 Iasi, Romania.,Department of Medical Genetics, Grigore T. Popa University of Medicine and Pharmacy, 700115 Iasi, Romania
| | - Adrian Lăcătuşu
- Department of Pediatrics, Victor Babeş University of Medicine and Pharmacy, 300041 Timisoara, Romania
| | - Monica Adriana Vaida
- Department of Anatomy and Embryology, Victor Babeş University of Medicine and Pharmacy, 300041 Timisoara, Romania
| | - Florin Bîrsăşteanu
- Department of Radiology and Medical Imaging, Victor Babeş University of Medicine and Pharmacy, 300041 Timisoara, Romania
| | - Maria Puiu
- Department of Microscopic Morphology, Victor Babeş University of Medicine and Pharmacy, 300041 Timisoara, Romania
| | - Dorina Stoicănescu
- Department of Microscopic Morphology, Victor Babeş University of Medicine and Pharmacy, 300041 Timisoara, Romania
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6
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Dijk DR, Bocca G, van Ravenswaaij-Arts CM. Growth in CHARGE syndrome: optimizing care with a multidisciplinary approach. J Multidiscip Healthc 2019; 12:607-620. [PMID: 31534343 PMCID: PMC6682174 DOI: 10.2147/jmdh.s175713] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 07/12/2019] [Indexed: 12/29/2022] Open
Abstract
CHARGE (Coloboma of the eye, Heart defects, Atresia of the choanae, Retardation of growth and/or development, Genital hypoplasia, Ear anomalies including hearing loss) syndrome is a rare syndrome with an incidence of approximately 1:15,000 newborns. It is caused by pathogenic variants in the CHD7 gene and clinically characterized by a wide range of anomalies with variable expression. Growth retardation affects 60-72% of children with CHARGE syndrome, making it one of the most prominent medical issues in the syndrome. Growth retardation in CHARGE syndrome is thought to be multifactorial and can be influenced by almost all co-morbidities, requiring a multidisciplinary approach to the different medical problems. In this systematic review, we describe what is currently known about growth in CHARGE syndrome and how it is influenced by commonly seen clinical problems including feeding difficulties, hypogonadotropic hypogonadism and growth hormone deficiency. Furthermore, we provide recommendations for a multidisciplinary approach.
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Affiliation(s)
- Dieuwerke R Dijk
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Gianni Bocca
- Department of Pediatrics, Beatrix Children's Hospital, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Conny M van Ravenswaaij-Arts
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
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7
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Matías-Pérez D, García-Montaño LA, Cruz-Aguilar M, García-Montalvo IA, Nava-Valdéz J, Barragán-Arevalo T, Villanueva-Mendoza C, Villarroel CE, Guadarrama-Vallejo C, la Cruz RVD, Chacón-Camacho O, Zenteno JC. Identification of novel pathogenic variants and novel gene-phenotype correlations in Mexican subjects with microphthalmia and/or anophthalmia by next-generation sequencing. J Hum Genet 2018; 63:1169-1180. [PMID: 30181649 DOI: 10.1038/s10038-018-0504-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 07/21/2018] [Accepted: 08/03/2018] [Indexed: 01/01/2023]
Abstract
Severe congenital eye malformations, particularly microphthalmia and anophthalmia, are one of the main causes of visual handicap worldwide. They can arise from multifactorial, chromosomal, or monogenic factors and can be associated with extensive clinical variability. Genetic analysis of individuals with these defects has allowed the recognition of dozens of genes whose mutations lead to disruption of normal ocular embryonic development. Recent application of next generation sequencing (NGS) techniques for genetic screening of patients with congenital eye defects has greatly improved the recognition of monogenic cases. In this study, we applied clinical exome NGS to a group of 14 Mexican patients (including 7 familial and 7 sporadic cases) with microphthalmia and/or anophthalmia. Causal or likely causal pathogenic variants were demonstrated in ~60% (8 out of 14 patients) individuals. Seven out of 8 different identified mutations occurred in well-known microphthalmia/anophthalmia genes (OTX2, VSX2, MFRP, VSX1) or in genes associated with syndromes that include ocular defects (CHD7, COL4A1) (including two instances of CHD7 pathogenic variants). A single pathogenic variant was identified in PIEZO2, a gene that was not previously associated with isolated ocular defects. NGS efficiently identified the genetic etiology of microphthalmia/anophthalmia in ~60% of cases included in this cohort, the first from Mexican origin analyzed to date. The molecular defects identified through clinical exome sequencing in this study expands the phenotypic spectra of CHD7-associated disorders and implicate PIEZO2 as a candidate gene for major eye developmental defects.
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Affiliation(s)
| | - Leopoldo A García-Montaño
- Department of Genetics-Research Unit, Institute of Ophthalmology "Conde de Valenciana", Mexico City, Mexico
| | - Marisa Cruz-Aguilar
- Department of Genetics-Research Unit, Institute of Ophthalmology "Conde de Valenciana", Mexico City, Mexico
| | | | - Jessica Nava-Valdéz
- Department of Genetics-Research Unit, Institute of Ophthalmology "Conde de Valenciana", Mexico City, Mexico
| | - Tania Barragán-Arevalo
- Department of Human Genetics, National Institute of Pediatrics of Mexico, Mexico City, Mexico
| | - Cristina Villanueva-Mendoza
- Department of Genetics, Hospital "Dr. Luis Sanchez Bulnes", Asociación Para Evitar la Ceguera en México, Mexico City, Mexico
| | - Camilo E Villarroel
- Department of Human Genetics, National Institute of Pediatrics of Mexico, Mexico City, Mexico
| | - Clavel Guadarrama-Vallejo
- Department of Genetics-Research Unit, Institute of Ophthalmology "Conde de Valenciana", Mexico City, Mexico
| | - Rocío Villafuerte-de la Cruz
- Ciencias Basicas, Escuela de Medicina, Instituto Tecnológico y de Estudios Superiores de Monterrey, Monterrey, NL, Mexico
| | - Oscar Chacón-Camacho
- Department of Genetics-Research Unit, Institute of Ophthalmology "Conde de Valenciana", Mexico City, Mexico
| | - Juan C Zenteno
- Department of Genetics-Research Unit, Institute of Ophthalmology "Conde de Valenciana", Mexico City, Mexico. .,Department of Biochemistry, Faculty of Medicine, UNAM, Mexico City, Mexico.
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8
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Moccia A, Martin DM. Nervous system development and disease: A focus on trithorax related proteins and chromatin remodelers. Mol Cell Neurosci 2018; 87:46-54. [PMID: 29196188 PMCID: PMC5828982 DOI: 10.1016/j.mcn.2017.11.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 11/08/2017] [Accepted: 11/27/2017] [Indexed: 01/12/2023] Open
Abstract
The nervous system comprises many different cell types including neurons, glia, macrophages, and immune cells, each of which is defined by specific patterns of gene expression, morphology, function, and anatomical location. Establishment of these complex and highly regulated cell fates requires spatial and temporal coordination of gene transcription. Open chromatin (euchromatin) allows transcription factors to interact with gene promoters and activate lineage specific genes, whereas closed chromatin (heterochromatin) remains inaccessible to transcriptional activation. Changes in the genome-wide distribution of euchromatin accompany transcriptional plasticity that allows the diversity of mature cell fates to be generated during development. In the past 20years, many new genes and gene families have been identified to participate in regulation of chromatin accessibility. These genes include chromatin remodelers that interact with Trithorax group (TrxG) and Polycomb group (PcG) proteins to activate or repress transcription, respectively. Here we review the role of TrxG proteins in neurodevelopment and disease.
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Affiliation(s)
- Amanda Moccia
- Department of Human Genetics, The University of Michigan Medical School, Ann Arbor, MI 48109, United States
| | - Donna M Martin
- Department of Human Genetics, The University of Michigan Medical School, Ann Arbor, MI 48109, United States; Department of Pediatrics and Communicable Diseases, The University of Michigan Medical School, Ann Arbor, MI 48109, United States.
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9
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Lee B, Duz MB, Sagong B, Koparir A, Lee KY, Choi JY, Seven M, Yuksel A, Kim UK, Ozen M. Revealing the function of a novel splice-site mutation of CHD7 in CHARGE syndrome. Gene 2015; 576:776-81. [PMID: 26551301 DOI: 10.1016/j.gene.2015.11.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Revised: 09/24/2015] [Accepted: 11/04/2015] [Indexed: 11/27/2022]
Abstract
Most cases of CHARGE syndrome are sporadic and autosomal dominant. CHD7 is a major causative gene of CHARGE syndrome. In this study, we screened CHD7 in two Turkish patients demonstrating symptoms of CHARGE syndrome such as coloboma, heart defect, choanal atresia, retarded growth, genital abnomalities and ear anomalies. Two mutations of CHD7 were identified including a novel splice-site mutation (c.2443-2A>G) and a previously known frameshift mutation (c.2504_2508delATCTT). We performed exon trapping analysis to determine the effect of the c.2443-2A>G mutation at the transcriptional level, and found that it caused a complete skip of exon 7 and splicing at a cryptic splice acceptor site. Our current study is the second study demonstrating an exon 7 deficit in CHD7. Results of previous studies suggest that the c.2443-2A>G mutation affects the formation of nasal tissues and the neural retina during early development, resulting in choanal atresia and coloboma, respectively. The findings of the present study will improve our understanding of the genetic causes of CHARGE syndrome.
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Affiliation(s)
- Byeonghyeon Lee
- Department of Biology, College of Natural Sciences, Kyungpook National University, Daegu, South Korea; School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, Kyungpook National University, Daegu, South Korea
| | - Mehmet Bugrahan Duz
- Department of Medical Genetics, Istanbul University Cerrahpasa Medical School, Istanbul, Turkey
| | - Borum Sagong
- Department of Biology, College of Natural Sciences, Kyungpook National University, Daegu, South Korea; School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, Kyungpook National University, Daegu, South Korea
| | - Asuman Koparir
- Department of Medical Genetics, Istanbul University Cerrahpasa Medical School, Istanbul, Turkey
| | - Kyu-Yup Lee
- Department of Otorhinolaryngology-Head and Neck Surgery, School of Medicine, Kyungpook National University, Daegu, South Korea
| | - Jae Young Choi
- Department of Otorhinolaryngology, Yonsei University College of Medicine, Seoul, South Korea
| | - Mehmet Seven
- Department of Medical Genetics, Istanbul University Cerrahpasa Medical School, Istanbul, Turkey
| | - Adnan Yuksel
- Department of Medical Genetics, Biruni University Medical School, Istanbul, Turkey
| | - Un-Kyung Kim
- Department of Biology, College of Natural Sciences, Kyungpook National University, Daegu, South Korea; School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, Kyungpook National University, Daegu, South Korea.
| | - Mustafa Ozen
- Department of Medical Genetics, Istanbul University Cerrahpasa Medical School, Istanbul, Turkey; Department of Medical Genetics, Biruni University Medical School, Istanbul, Turkey; Department of Pathology & Immunology, Baylor College of Medicine, Michael E. DeBakey VAMC, Houston, TX, United States.
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10
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Basson MA, van Ravenswaaij-Arts C. Functional Insights into Chromatin Remodelling from Studies on CHARGE Syndrome. Trends Genet 2015; 31:600-11. [PMID: 26411921 DOI: 10.1016/j.tig.2015.05.009] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Revised: 05/25/2015] [Accepted: 05/26/2015] [Indexed: 12/27/2022]
Abstract
CHARGE syndrome is a rare genetic syndrome characterised by a unique combination of multiple organ anomalies. Dominant loss-of-function mutations in the gene encoding chromodomain helicase DNA binding protein 7 (CHD7), which is an ATP-dependent chromatin remodeller, have been identified as the cause of CHARGE syndrome. Here, we review recent work aimed at understanding the mechanism of CHD7 function in normal and pathological states, highlighting results from biochemical and in vivo studies. The emerging picture from this work suggests that the mechanisms by which CHD7 fine-tunes gene expression are context specific, consistent with the pleiotropic nature of CHARGE syndrome.
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11
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Martínez-Quintana E, Rodríguez-González F, Garay-Sánchez P, Tugores A. Novel Frameshift CHD7 Mutation Related to CHARGE Syndrome. Mol Syndromol 2013; 5:36-40. [PMID: 24550764 DOI: 10.1159/000355431] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/28/2013] [Indexed: 01/18/2023] Open
Abstract
CHARGE syndrome is a rare congenital condition characterized by 6 cardinal features: coloboma, heart defect, atresia choanae, retarded growth and development, genital anomalies, and ear anomalies/deafness. Mutations of the chromodomain helicase DNA-binding protein gene CHD7 are reported to be a major cause of CHARGE syndrome. Herein, we report the case of a 27-year-old patient presenting with typical symptoms who bears a novel heterozygous insertion in exon 2 of the CHD7 gene (c.327dupC) resulting in an amino acid substitution and a frameshift (p.Val110Argfs*22) that leads to a 131-amino-acid truncated polypeptide, likely representing a null allele. Parental genetic screening confirmed the sporadic origin of the mutation.
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Affiliation(s)
- E Martínez-Quintana
- Cardiology Service, Insular-Materno Infantil University Hospital, Las Palmas de Gran Canaria, Spain
| | - F Rodríguez-González
- Ophtalmology Service, Dr. Negrín University Hospital of Gran Canaria, Las Palmas de Gran Canaria, Spain
| | - P Garay-Sánchez
- Research Unit, Insular-Materno Infantil University Hospital, Las Palmas de Gran Canaria, Spain
| | - A Tugores
- Research Unit, Insular-Materno Infantil University Hospital, Las Palmas de Gran Canaria, Spain
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Trevisson E, Forzan M, Salviati L, Clementi M. Neurofibromatosis type 1 in two siblings due to maternal germline mosaicism. Clin Genet 2013; 85:386-9. [PMID: 23621909 DOI: 10.1111/cge.12177] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Revised: 04/18/2013] [Accepted: 04/18/2013] [Indexed: 11/30/2022]
Abstract
Neurofibromatosis type 1 (NF1) is caused by loss of function mutations of the NF1 gene, which are de novo in 50% of cases. Although this gene shows one of the highest mutation rates in the human genome, germline mosaicism is very rare in this condition. We describe the molecular analysis of a family in which neurofibromatosis type 1 occurred in two out of four siblings born to unaffected parents. Molecular analysis of the NF1 gene identified in both patients the same splicing mutation c.1392+1G>A, which was absent in parental lymphocytes. Microsatellite analysis showed that the two affected siblings shared the same maternal allele, however a specific PCR-RFLP assay excluded the presence of the NF1 splicing mutation in multiple maternal tissues. Our molecular and clinical findings are consistent with a germline mosaicism for the NF1 splicing mutation. This is the first case of maternal germline mosaicism for a NF1 mutation characterized so far at the molecular level. Our data confirm that germline mosaicism is rare in neurofibromatosis 1, but it has important implications for genetic counseling.
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Affiliation(s)
- E Trevisson
- Clinical Genetics Unit, Department of Woman and Child Health, University of Padova, Padova, Italy
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Steinbusch CVM, van Roozendaal KEP, Tserpelis D, Smeets EEJ, Kranenburg-de Koning TJ, de Waal KH, Zweier C, Rauch A, Hennekam RCM, Blok MJ, Schrander-Stumpel CTRM. Somatic mosaicism in a mother of two children with Pitt-Hopkins syndrome. Clin Genet 2013; 83:73-7. [DOI: 10.1111/j.1399-0004.2012.01857.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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14
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Palumbo O, Palumbo P, Stallone R, Palladino T, Zelante L, Carella M. 8q12.1q12.3 de novo microdeletion involving the CHD7 gene in a patient without the major features of CHARGE syndrome: case report and critical review of the literature. Gene 2012; 513:209-13. [PMID: 23142376 DOI: 10.1016/j.gene.2012.09.132] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Revised: 09/24/2012] [Accepted: 09/29/2012] [Indexed: 12/12/2022]
Abstract
CHARGE syndrome is an autosomal dominant inherited disorder characterized by a specific and recognizable pattern of anomalies. De novo mutations or deletions of the gene encoding chromodomain helicase DNA binding protein 7 (CHD7) are the major cause of CHARGE syndrome. In this report, we describe a patient with a typical phenotype characterized by psychomotor retardation, hypertrichosis, facial asymmetry, synophria, failure to thrive, developmental delay and gastro-esophageal reflux, carrying a de novo 6.04Mb interstitial deletion in 8q12.1q12.3 detected by single nucleotide polymorphism (SNP) array analysis. Despite the deletion includes CHD7 and although the patient shares some of the clinical features of the CHARGE syndrome, she does not fulfill the clinical criteria for this syndrome. To the best of our knowledge, this is the second case with an entire deletion of the CHD7 gene not leading to CHARGE syndrome and, for this reason, useful to expand and further delineate the clinical features associated with the 8q12.1q12.3 deletion. Furthermore, the literature review revealed that the phenotype secondary to duplications of the same region partially overlaps with the phenotype reported in this study. Selected genes that are present in the hemizygous state and which might be important for the phenotype of this patient, are discussed in context of the clinical features.
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Affiliation(s)
- Orazio Palumbo
- Medical Genetics Unit, IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo (FG), Italy
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15
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Janssen N, Bergman JEH, Swertz MA, Tranebjaerg L, Lodahl M, Schoots J, Hofstra RMW, van Ravenswaaij-Arts CMA, Hoefsloot LH. Mutation update on the CHD7 gene involved in CHARGE syndrome. Hum Mutat 2012; 33:1149-60. [DOI: 10.1002/humu.22086] [Citation(s) in RCA: 177] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Accepted: 03/06/2012] [Indexed: 12/17/2022]
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Abstract
Germline mosaicism is a genetic condition in which some germ cells of an individual contain a mutation. This condition violates the assumptions underlying classic genetic analysis and may lead to failure of such analysis. In this work we extend the statistical model used for genetic linkage analysis in order to incorporate germline mosaicism. We develop a likelihood ratio test for detecting whether a genetic trait has been introduced into a pedigree by germline mosaicism. We analyze the statistical properties of this test and evaluate its performance via computer simulations. We demonstrate that genetic linkage analysis has high power to identify linkage in the presence of germline mosaicism when our extended model is used. We further use this extended model to provide solid statistical evidence that the MDN syndrome studied by Genzer-Nir et al. has been introduced by germline mosaicism.
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Pauli S, von Velsen N, Burfeind P, Steckel M, Mänz J, Buchholz A, Borozdin W, Kohlhase J. CHD7 mutations causing CHARGE syndrome are predominantly of paternal origin. Clin Genet 2011; 81:234-9. [DOI: 10.1111/j.1399-0004.2011.01701.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Bartels CF, Scacheri C, White L, Scacheri PC, Bale S. Mutations in the CHD7 gene: the experience of a commercial laboratory. Genet Test Mol Biomarkers 2011; 14:881-91. [PMID: 21158681 DOI: 10.1089/gtmb.2010.0101] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
CHARGE syndrome is an autosomal dominant multisystem disorder caused by mutation in the CHD7 gene, encoding chromodomain helicase DNA-binding protein 7. Molecular diagnostic testing for CHD7 mutation has been available in a clinical setting since 2005. We report here the results from the first 642 unrelated proband samples submitted for testing. Thirty-two percent (n = 203) of patient samples had a heterozygous pathogenic variant identified. The lower mutation rate than that published for well-characterized clinical samples is likely due to referral bias, as samples submitted for clinical testing may be for "rule-out" diagnoses, rather than solely to confirm clinical suspicion. We identified 159 unique pathogenic mutations, and of these, 134 mutations were each seen in a single individual and 25 mutations were found in two to five individuals (n =69). Of the 203 mutations, only 9 were missense, with 107 nonsense, 69 frameshift, and 15 splice-site mutations likely leading to haploinsufficiency at the cellular level. An additional 72 variations identified in the 642 tested samples (11%) were considered to have unknown clinical significance. Copy number changes (deletion/duplication of the entire gene or one/several exons) were found to account for a very small number of cases (n = 3). This cohort represents the largest CHARGE syndrome sample size to date and is intended to serve as a resource for clinicians, genetic counselors, researchers, and other diagnostic laboratories.
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Affiliation(s)
- Cynthia F Bartels
- Department of Genetics, Case Western Reserve University, Cleveland, Ohio 44016, USA
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Hartshorne TS, Stratton KK, van Ravenswaaij-Arts CMA. Prevalence of Genetic Testing in CHARGE Syndrome. J Genet Couns 2010; 20:49-57. [DOI: 10.1007/s10897-010-9328-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2010] [Accepted: 09/05/2010] [Indexed: 01/08/2023]
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Wessels K, Bohnhorst B, Luhmer I, Morlot S, Bohring A, Jonasson J, Epplen JT, Gadzicki D, Glaser S, Göhring G, Mälzer M, Hein A, Arslan-Kirchner M, Stuhrmann M, Schmidtke J, Pabst B. Novel CHD7 mutations contributing to the mutation spectrum in patients with CHARGE syndrome. Eur J Med Genet 2010; 53:280-5. [PMID: 20624498 DOI: 10.1016/j.ejmg.2010.07.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2010] [Accepted: 07/04/2010] [Indexed: 10/19/2022]
Abstract
CHARGE syndrome is an autosomal dominant inherited multiple malformation disorder typically characterized by coloboma, choanal atresia, hypoplastic semicircular canal, cranial nerve defects, cardiovascular malformations and ear abnormalities. Mutations in the chromodomain helicase DNA-binding protein 7 (CHD7) gene are the major cause of CHARGE syndrome. Mutation analysis was performed in 18 patients with firm or tentative clinical diagnosis of CHARGE syndrome. In this study eight mutations distributed across the gene were found. Five novel mutations - one missense (c.2936T > C), one nonsense (c.8093C > A) and three frameshift mutations (c.804_805insAT, c.1757_1770del14, c.1793delA) - were identified. As far as familial data were available these mutations were found to have arisen de novo. Comparison of the clinical features of patients with the same mutation demonstrates that expression of the phenotype is highly variable. The mutation detection rate in this study was 44.4% in patients with a clinically established or suspected diagnosis of CHARGE syndrome.
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Affiliation(s)
- Kathrin Wessels
- Institute of Human Genetics, Hannover Medical School, Hannover, Germany
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Abstract
CHARGE syndrome [coloboma of the eye, heart defects, atresia of the choanae, retardation of growth and/or development, genital and/or urinary abnormalities, and ear abnormalities (including deafness)] is a genetic disorder characterized by a specific and a recognizable pattern of anomalies. De novo mutations in the gene encoding chromodomain helicase DNA binding protein 7 (CHD7) are the major cause of CHARGE syndrome. Here, we review the clinical features of 379 CHARGE patients who tested positive or negative for mutations in CHD7. We found that CHARGE individuals with CHD7 mutations more commonly have ocular colobomas, temporal bone anomalies (semicircular canal hypoplasia/dysplasia), and facial nerve paralysis compared with mutation negative individuals. We also highlight recent genetic and genomic studies that have provided functional insights into CHD7 and the pathogenesis of CHARGE syndrome.
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Affiliation(s)
- Gabriel E Zentner
- Department of Genetics, Case Western Reserve University, Cleveland, Ohio, USA
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Abstract
In humans, heterozygous mutations in the adenosine triphosphate-dependent chromatin remodeling gene CHD7 cause CHARGE syndrome, a common cause of deaf-blindness, balance disorders, congenital heart malformations, and olfactory dysfunction with an estimated incidence of approximately 1 in 10,000 newborns. The clinical features of CHARGE in humans and mice are highly variable and incompletely penetrant, and most mutations appear to result in haploinsufficiency of functional CHD7 protein. Mice with heterozygous loss of function mutations in Chd7 are a good model for CHARGE syndrome, and analyses of mouse mutant phenotypes have begun to clarify a role for CHD7 during development and into adulthood. Chd7 heterozygous mutant mice have postnatal delayed growth, inner ear malformations, anosmia/hyposmia, and craniofacial defects, and Chd7 homozygous mutants are embryonic lethal. A central question in developmental biology is how chromodomain proteins like CHD7 regulate important developmental processes, and whether they directly activate or repress downstream gene transcription or act more globally to alter chromatin structure and/or function. CHD7 is expressed in a wide variety of tissues during development, suggesting that it has tissue-specific and developmental stage-specific roles. Here, we review recent and ongoing analyses of CHD7 function in mouse models and cell-based systems. These studies explore tissue-specific effects of CHD7 deficiency, known CHD7 interacting proteins, and downstream target sites for CHD7 binding. CHD7 is emerging as a critical regulator of important developmental processes in organs affected by human CHARGE syndrome.
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Affiliation(s)
- W S Layman
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI, USA
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