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Jiang Y, Peng Y, Tian Q, Cheng Z, Feng B, Hu J, Xia L, Guo H, Xia K, Zhou L, Hu Z. Intergenic sequences harboring potential enhancer elements contribute to Axenfeld-Rieger syndrome by regulating PITX2. JCI Insight 2024; 9:e177032. [PMID: 38592784 PMCID: PMC11141933 DOI: 10.1172/jci.insight.177032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Accepted: 03/27/2024] [Indexed: 04/11/2024] Open
Abstract
Recent studies have uncovered that noncoding sequence variants may relate to Axenfeld-Rieger syndrome (ARS), a rare developmental anomaly with genetic heterogeneity. However, how these genomic regions are functionally and structurally associated with ARS is still unclear. In this study, we performed genome-wide linkage analysis and whole-genome sequencing in a Chinese family with ARS and identified a heterozygous deletion of about 570 kb (termed LOH-1) in the intergenic sequence between paired-like homeodomain transcription factor 2 (PITX2) and family with sequence similarity 241 member A. Knockout of LOH-1 homologous sequences caused ARS phenotypes in mice. RNA-Seq and real-time quantitative PCR revealed a significant reduction in Pitx2 gene expression in LOH-1-/- mice, while forkhead box C1 expression remained unchanged. ChIP-Seq and bioinformatics analysis identified a potential enhancer region (LOH-E1) within LOH-1. Deletion of LOH-E1 led to a substantial downregulation of the PITX2 gene. Mechanistically, we found a sequence (hg38 chr4:111,399,594-111,399,691) that is on LOH-E1 could regulate PITX2 by binding to RAD21, a critical component of the cohesin complex. Knockdown of RAD21 resulted in reduced PITX2 expression. Collectively, our findings indicate that a potential enhancer sequence that is within LOH-1 may regulate PITX2 expression remotely through cohesin-mediated loop domains, leading to ARS when absent.
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Affiliation(s)
- Yizheng Jiang
- MOE Key Laboratory of Rare Pediatric Diseases & Hunan Key Laboratory of Medical Genetics of the School of Life Sciences and
| | - Yu Peng
- Department of Medical Genetics, The Affiliated Children’s Hospital of Xiangya School of Medicine, Central South University, Changsha, China
| | - Qi Tian
- MOE Key Laboratory of Rare Pediatric Diseases & Hunan Key Laboratory of Medical Genetics of the School of Life Sciences and
| | - Zhe Cheng
- MOE Key Laboratory of Rare Pediatric Diseases & Hunan Key Laboratory of Medical Genetics of the School of Life Sciences and
| | - Bei Feng
- MOE Key Laboratory of Rare Pediatric Diseases & Hunan Key Laboratory of Medical Genetics of the School of Life Sciences and
| | - Junping Hu
- MOE Key Laboratory of Rare Pediatric Diseases & Hunan Key Laboratory of Medical Genetics of the School of Life Sciences and
| | - Lu Xia
- MOE Key Laboratory of Rare Pediatric Diseases & Hunan Key Laboratory of Medical Genetics of the School of Life Sciences and
| | - Hui Guo
- MOE Key Laboratory of Rare Pediatric Diseases & Hunan Key Laboratory of Medical Genetics of the School of Life Sciences and
| | - Kun Xia
- MOE Key Laboratory of Rare Pediatric Diseases & Hunan Key Laboratory of Medical Genetics of the School of Life Sciences and
- MOE Key Laboratory of Rare Pediatric Diseases, Hengyang Medical School, University of South China, Hengyang, China
| | - Liang Zhou
- Department of Ophthalmology, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Zhengmao Hu
- MOE Key Laboratory of Rare Pediatric Diseases & Hunan Key Laboratory of Medical Genetics of the School of Life Sciences and
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4q25 Microdeletion with Axenfeld-Rieger Syndrome and Developmental Delay. Case Rep Genet 2023; 2023:4592114. [PMID: 36816813 PMCID: PMC9935865 DOI: 10.1155/2023/4592114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 01/25/2023] [Accepted: 01/27/2023] [Indexed: 02/11/2023] Open
Abstract
We encountered a case with congenital iris coloboma, omphalocele, and developmental delay with a 2.5 Mb deletion on chromosome 4q25 encompassing PITX2, leading to Axenfeld-Rieger syndrome (ARS), NEUROG2, and ANK2. ARS is characterized by the aplasia of the anterior eye, odontogenesis, and abdominal wall aplasia. In our case, iris coloboma and omphalocele were thought to be caused by PITX2 haploinsufficiency. However, these symptoms are nonspecific, and clinical symptoms alone can make it difficult to make a correct diagnosis. In addition, the genes responsible for developmental delay, among others, are not well understood. Developmental delay, in this case, might be caused due to NEUROG2 haploinsufficiency. In spite of the partial deletion of ANK2, the causative gene of long QT syndrome type 4, the electrocardiogram was normal. Genetic testing can lead to a correct diagnosis, and it may be effective in detecting complications.
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Early-Onset Glaucoma in egl1 Mice Homozygous for Pitx2 Mutation. Biomedicines 2022; 10:biomedicines10030516. [PMID: 35327318 PMCID: PMC8945683 DOI: 10.3390/biomedicines10030516] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 02/18/2022] [Accepted: 02/19/2022] [Indexed: 02/04/2023] Open
Abstract
Mutations in PITX2 cause Axenfeld–Rieger syndrome, with congenital glaucoma as an ocular feature. The egl1 mouse strain carries a chemically induced Pitx2 mutation and develops early-onset glaucoma. In this study, we characterized the glaucomatous features in egl1 mice. The eyes of egl1 and C57BL/6J control mice were assessed by slit lamp examination, total aqueous humor outflow facility, intraocular pressure (IOP) measurement, pattern electroretinography (PERG) recording, and histologic and immunohistochemistry assessment beginning at 3 weeks and up to 12 months of age. The egl1 mice developed elevated IOP as early as 4 weeks old. The IOP elevation was variable and asymmetric within and between the animals. The aqueous humor outflow facility was significantly reduced in 12-month-old animals. PERG detected a decreased response at 2 weeks after the development of IOP elevation. Retinal ganglion cell (RGC) loss was detected after 8 weeks of IOP elevation. Slit lamp and histologic evaluation revealed corneal opacity, iridocorneal adhesions (anterior synechiae), and ciliary body atrophy in egl1 mice. Immunohistochemistry assessment demonstrated glial cell activation and RGC axonal injury in response to IOP elevation. These results show that the eyes of egl1 mice exhibit anterior segment dysgenesis and early-onset glaucoma. The egl1 mouse strain may represent a useful model for the study of congenital glaucoma.
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Gołaszewska K, Dub N, Saeed E, Mariak Z, Konopińska J. Axenfeld-Rieger syndrome combined with a foveal anomaly in a three-generation family: a case report. BMC Ophthalmol 2021; 21:154. [PMID: 33781219 PMCID: PMC8008669 DOI: 10.1186/s12886-021-01899-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 03/10/2021] [Indexed: 11/10/2022] Open
Abstract
Background Axenfeld-Rieger syndrome (ARS) is a rare autosomal dominant eye disorder that can also affect other organs of the human body. The condition is primarily characterized by the anterior segmental abnormalities of the eye. Here, we present an observational case series of a three-generation family with ARS and unexpected foveal anomaly. Case presentation A 33-year-old woman was admitted to an Ophthalmology Clinic in Bialystok for left eye congenital cataract surgery. The patient (proband) was diagnosed with visual deterioration, multiple defects of iris, corectopia, displacement of the Schwalbe’s line, and phenotypic characteristics of ARS. A perimetric examination indicated peripheral visual field loss and signs typical for glaucoma. Based on the phenotypic symptoms and genetic test, the patient was diagnosed with Axenfeld Rieger Syndrome. However, the optical coherence tomography of the macula showed foveal anomaly (absence of the physiological pit), which is not typically associated with this genetic disorder. The patient’s family history revealed that her two daughters were undergoing treatment for congenital glaucoma, and one of the daughters also had foveal anomaly the same as her mother. Interestingly, an examination of the patient’s mother showed typical phenotypic features of ARS such as a defect of the iris, posterior embryotoxon, and coloboma, as well as foveal anomaly. A genetic test confirmed PITX2 mutation in both, proband’s two daughters and mother. Conclusions This study highlights the occurrence of ARS with unusual ophthalmic features such as foveal anomaly (absence of the physiological pit) in a three-generation family. Although ARS is known to represent the developmental defects of the anterior segment of the eye, it is very important to perform fundus evaluation to identify associated posterior segment anomalies that may affect visual acuity. The presence of ocular defects not typically associated with ARS suggests a wide spectrum of mutations within PITX2 gene which are required to identify in order to determine genotype- phenotype correlation in ARS affected individuals.
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Affiliation(s)
- Kinga Gołaszewska
- Department of Ophthalmology, Medical University of Bialystok, Jana Kilinskiego 1 STR, 15-089, Białystok, Poland
| | - Natalia Dub
- Department of Ophthalmology, Medical University of Bialystok, Jana Kilinskiego 1 STR, 15-089, Białystok, Poland
| | - Emil Saeed
- Department of Ophthalmology, Medical University of Bialystok, Jana Kilinskiego 1 STR, 15-089, Białystok, Poland
| | - Zofia Mariak
- Department of Ophthalmology, Medical University of Bialystok, Jana Kilinskiego 1 STR, 15-089, Białystok, Poland
| | - Joanna Konopińska
- Department of Ophthalmology, Medical University of Bialystok, Jana Kilinskiego 1 STR, 15-089, Białystok, Poland.
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Walter MA, Rezaie T, Hufnagel RB, Arno G. Ocular genetics in the genomics age. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2020; 184:860-868. [PMID: 32896097 DOI: 10.1002/ajmg.c.31844] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 08/14/2020] [Accepted: 08/17/2020] [Indexed: 12/29/2022]
Abstract
Current genetic screening methods for inherited eye diseases are concentrated on the coding exons of known disease genes (gene panels, clinical exome). These tests have a variable and often limited diagnostic rate depending on the clinical presentation, size of the gene panel and our understanding of the inheritance of the disorder (with examples described in this issue). There are numerous possible explanations for the missing heritability of these cases including undetected variants within the relevant gene (intronic, up/down-stream and structural variants), variants harbored in genes outside the targeted panel, intergenic variants, variants undetectable by the applied technology, complex/non-Mendelian inheritance, and nongenetic phenocopies. In this article we further explore and review methods to investigate these sources of missing heritability.
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Affiliation(s)
- Michael A Walter
- Department of Medical Genetics, University of Alberta, Edmonton, Alberta, Canada
| | - Tayebeh Rezaie
- National Center for Biotechnology Information, National Institutes of Health, Bethesda, Maryland, USA
| | - Robert B Hufnagel
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Gavin Arno
- University College London Institute of Ophthalmology, London, UK.,Moorfields Eye Hospital, London, UK
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Novel PITX2 Mutations including a Mutation Causing an Unusual Ophthalmic Phenotype of Axenfeld-Rieger Syndrome. J Ophthalmol 2019; 2019:5642126. [PMID: 31341655 PMCID: PMC6636469 DOI: 10.1155/2019/5642126] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 02/23/2019] [Accepted: 03/06/2019] [Indexed: 12/22/2022] Open
Abstract
Purpose The aims of this study were to examine novel mutations in PITX2 and FOXC1 in Chinese patients with anterior segment dysgenesis (ASD) and to compare the clinical presentations of these mutations with previously reported associated phenotypes. Methods Twenty-six unrelated patients with different forms of ASD were enrolled from our paediatric and genetic eye clinic. The ocular manifestations of both eyes of each patient were recorded. Genomic DNA was prepared from venous leukocytes. All coding exons of PITX2 and FOXC1 were amplified by polymerase chain reaction (PCR) from genomic DNA and subjected to direct DNA sequencing. Analysis of mutations in control subjects was performed by heteroduplex single-strand conformation polymorphism (SSCP) analysis. Results Sequence analysis of the PITX2 gene revealed four mutations, including c.475_476delCT (P.L159VfsX39), c.64C > T (P.Q22X), c.296delG (P.R99PfsX56), and c.206G > A (P.R69H). The first three mutations were found to be novel. The c.475_476delCT (P.L159VfsX39) mutation, located at the 3' end of the PITX2-coding region, was identified in a Chinese Axenfeld-Rieger syndrome (ARS) patient who presented with an unusual severe phenotype of bilateral aniridia. The clinical characteristics, including the severity and manifestations of the patient's phenotype, were compared with reported PITX2-associated aniridia phenotypes of ARS in the literature. Conclusions These results expand the mutation spectrum of the PITX2 gene in patients with ARS. The PITX2 gene may be responsible for a significant portion of ARS with additional systemic defects in the Chinese population. This is the first reported case of a mutation at the 3' end of the PITX2-coding region extending the phenotypic consequences to bilateral aniridia. The traits of ARS could display tremendous variability in severity and manifestations due to the dominant-negative effect of PITX2. Our results further emphasize the importance of careful clinical and genetic analysis in determining mutation-disease associations and may lead to a better understanding of the role of PITX2 in ocular development.
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Seifi M, Walter MA. Axenfeld-Rieger syndrome. Clin Genet 2018; 93:1123-1130. [PMID: 28972279 DOI: 10.1111/cge.13148] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 09/23/2017] [Accepted: 09/26/2017] [Indexed: 12/29/2022]
Abstract
Axenfeld-Rieger syndrome (ARS) is a clinically and genetically heterogeneous group of developmental disorders affecting primarily the anterior segment of the eye, often leading to secondary glaucoma. Patients with ARS may also present with systemic changes, including dental defects, mild craniofacial dysmorphism, and umbilical anomalies. ARS is inherited in an autosomal-dominant fashion; the underlying defect in 40% of patients is mutations in PITX2 or FOXC1. Here, an overview of the clinical spectrum of ARS is provided. As well, the known underlying genetic defects, clinical diagnostic possibilities, genetic counseling and treatments of ARS are discussed in detail.
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Affiliation(s)
- M Seifi
- Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Alberta, Edmonton, Canada
| | - M A Walter
- Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Alberta, Edmonton, Canada
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Novel Genetic Findings in a Chinese Family with Axenfeld-Rieger Syndrome. J Ophthalmol 2017; 2017:5078079. [PMID: 28695001 PMCID: PMC5485333 DOI: 10.1155/2017/5078079] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 05/14/2017] [Indexed: 11/30/2022] Open
Abstract
Purpose To describe a Chinese family with Axenfeld-Rieger syndrome (ARS) and report our novel genetic findings. Methods Nine members of the same family underwent complete ophthalmologic examinations and genetic analysis. Genomic DNA was isolated from veinal blood and amplifed using PCR; the products of PCR were sequenced and compared with FOXC1 and PITX2 genes, from which the mutations were found. Results Through the ophthalmologic examinations, 8 subjects were diagnosed as ARS and 1 subject was normal. A homozygous mutation c.1139_1141dupGCG(p.Gly380_Ala381insGly) and a heterozygous mutation c.1359_1361dupCGG(p.Gly456_Gln457insGly) in FOXC1 were identified in all subjects. The mutation (c.-10-30T>C) was identified in PITX2 in subjects III-1 and III-3. Conclusions We found novel gene mutations in a Chinese family with ARS, which provides us with a better understanding of the gene mutation spectrum of ARS and the assistance for the genetic counseling and gene-specific therapy in the future.
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Micheal S, Siddiqui SN, Zafar SN, Venselaar H, Qamar R, Khan MI, den Hollander AI. Whole exome sequencing identifies a heterozygous missense variant in the PRDM5 gene in a family with Axenfeld-Rieger syndrome. Neurogenetics 2015; 17:17-23. [PMID: 26489929 PMCID: PMC4701771 DOI: 10.1007/s10048-015-0462-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 09/20/2015] [Indexed: 12/03/2022]
Abstract
Axenfeld–Rieger syndrome (ARS) is a disorder affecting the anterior segment of the eye, often leading to secondary glaucoma and several systemic malformations. It is inherited in an autosomal dominant fashion that has been associated with genetic defects in PITX2 and FOXC1. Known genes CYP1b1, PITX2, and FOXC1 were excluded by Sanger sequencing. The purpose of current study is to identify the underlying genetic causes in ARS family by whole exome sequencing (WES). WES was performed for affected proband of family, and variants were prioritized based on in silico analyses. Segregation analysis of candidate variants was performed in family members. A novel heterozygous PRDM5 missense variant (c.877A>G; p.Lys293Glu) was found to segregate with the disease in an autosomal dominant fashion. The novel missense variant was absent from population-matched controls, the Exome Variant Server, and an in-house exome variant database. The Lys293Glu variant is predicted to be pathogenic and affects a lysine residue that is conserved in different species. Variants in the PRDM5 gene were previously identified in anterior segment defects, i.e., autosomal recessive brittle cornea syndrome and keratoconus. The results of this study suggest that genetic variants in PRDM5 can lead to various syndromic and nonsyndromic disorders affecting the anterior segment of the eye.
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Affiliation(s)
- Shazia Micheal
- Department of Ophthalmology, Radboud University Medical Center, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands.
| | - Sorath Noorani Siddiqui
- Department of Pediatric Ophthalmology, Al-Shifa Eye Trust Hospital Jhelum Road, Rawalpindi, Pakistan
| | - Saemah Nuzhat Zafar
- Department of Pediatric Ophthalmology, Al-Shifa Eye Trust Hospital Jhelum Road, Rawalpindi, Pakistan
| | - Hanka Venselaar
- Center for Molecular and Biomolecular Informatics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Raheel Qamar
- Department of Biosciences, COMSATS Institute of Information Technology, Islamabad, Pakistan.,Al-Nafees Medical College and Hospital, Isra University, Islamabad, Pakistan
| | - Muhammad Imran Khan
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Anneke I den Hollander
- Department of Ophthalmology, Radboud University Medical Center, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands. .,Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.
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Yang HJ, Lee YK, Joo CK, Moon JI, Mok JW, Park MH. A Family with Axenfeld-Rieger Syndrome: Report of the Clinical and Genetic Findings. KOREAN JOURNAL OF OPHTHALMOLOGY 2015; 29:249-55. [PMID: 26240509 PMCID: PMC4520868 DOI: 10.3341/kjo.2015.29.4.249] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Accepted: 11/25/2014] [Indexed: 12/12/2022] Open
Abstract
PURPOSE To describe clinical findings in a Korean family with Axenfeld-Rieger syndrome. METHODS A retrospective review of clinical data about patients with diagnosed Axenfeld-Rieger syndrome. Five affected members of the family underwent a complete ophthalmologic examination. We screened the forkhead box C1 gene and the pituitary homeobox 2 gene in patients. Peripheral blood leukocytes and buccal mucosal epithelial cells were obtained from seven members of a family with Axenfeld-Rieger syndrome. DNA was extracted and amplified by polymerase chain reaction, followed by direct sequencing. RESULTS The affected members showed iris hypoplasia, iridocorneal adhesions, posterior embryotoxon, and advanced glaucoma in three generation. None had systemic anomalies. Two mutations including c.1362_1364insCGG and c.1142_1144insGGC were identified in forkhead box C1 in four affected family members. CONCLUSIONS This study may help to understand clinical findings and prognosis for patients with Axenfeld-Rieger syndrome.
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Affiliation(s)
- Hee Jung Yang
- Department of Ophthalmology, The Catholic University of Korea College of Medicine, Seoul, Korea
| | - You Kyung Lee
- Department of Ophthalmology, The Catholic University of Korea College of Medicine, Seoul, Korea
| | - Choun-Ki Joo
- Department of Ophthalmology, The Catholic University of Korea College of Medicine, Seoul, Korea
| | - Jung Il Moon
- Department of Ophthalmology, The Catholic University of Korea College of Medicine, Seoul, Korea
| | - Jee Won Mok
- Catholic Institute for Visual Science, Department of Ophthalmology and Visual Science, Seoul St. Mary's Hospital, The Catholic University of Korea College of Medicine, Seoul, Korea
| | - Myoung Hee Park
- Department of Ophthalmology, The Catholic University of Korea College of Medicine, Seoul, Korea
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Guerin A, So J, Mireskandari K, Jougeh-Doust S, Chisholm C, Klatt R, Richer J. Expanding the clinical spectrum of ocular anomalies in Noonan syndrome: Axenfeld-anomaly in a child withPTPN11mutation. Am J Med Genet A 2014; 167A:403-6. [DOI: 10.1002/ajmg.a.36841] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Accepted: 09/29/2014] [Indexed: 01/06/2023]
Affiliation(s)
- Andrea Guerin
- The Hospital for Sick Children; Department of Pediatrics; Division of Clinical and Metabolic Genetics; Toronto Ontario Canada
- Kingston General Hospital; Department of Pediatrics; Division of Medical Genetics; Kingston Ontario Canada
| | - Joyce So
- The Hospital for Sick Children; Department of Pediatrics; Division of Clinical and Metabolic Genetics; Toronto Ontario Canada
- The Centre for Addiction and Mental Health; Toronto; Ontario Canada
| | - Kamiar Mireskandari
- The Hospital for Sick Children; Department of Ophthalmology and Vision Sciences; Toronto Ontario Canada
| | - Soghra Jougeh-Doust
- The Hospital for Sick Children; Department of Pediatrics; Division of Clinical and Metabolic Genetics; Toronto Ontario Canada
| | - Caitlin Chisholm
- Children's Hospital of Eastern Ontario; Department of Medical Genetics; Ottawa Ontario Canada
| | - Regan Klatt
- The Hospital for Sick Children; Department of Pediatrics; Division of Clinical and Metabolic Genetics; Toronto Ontario Canada
| | - Julie Richer
- Children's Hospital of Eastern Ontario; Department of Medical Genetics; Ottawa Ontario Canada
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Abstract
The characterization of genes responsible for glaucoma is the critical first step toward the development of gene-based diagnostic and screening tests, which could identify individuals at risk for disease before irreversible optic nerve damage occurs. Early-onset forms of glaucoma affecting children and young adults are typically inherited as Mendelian autosomal dominant or recessive traits whereas glaucoma affecting older adults has complex inheritance. In this report, we present a comprehensive overview of the genes and genomic regions contributing to inherited glaucoma.
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Affiliation(s)
- Ryan Wang
- Department of Ophthalmology, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts 02114
| | - Janey L Wiggs
- Department of Ophthalmology, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts 02114
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13
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Yin HF, Fang XY, Jin CF, Yin JF, Li JY, Zhao SJ, Miao Q, Song FW. Identification of a novel frameshift mutation in PITX2 gene in a Chinese family with Axenfeld-Rieger syndrome. J Zhejiang Univ Sci B 2014; 15:43-50. [PMID: 24390743 PMCID: PMC3891117 DOI: 10.1631/jzus.b1300053] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2013] [Accepted: 07/01/2013] [Indexed: 11/11/2022]
Abstract
OBJECTIVE Axenfeld-Rieger syndrome (ARS) is phenotypically and genetically heterogeneous. In this study, we identified the underlying genetic defect in a Chinese family with ARS. METHODS A detailed family history and clinical data were recorded. The ocular phenotype was documented using slit-lamp photography and systemic anomalies were also documented where available. The genomic DNA was extracted from peripheral blood leukocytes. All coding exons and intron-exon junctions of paired-like homeodomain transcription factor 2 (PITX2) gene and the forkhead box C1 (FOXC1) gene were amplified by polymerase chain reaction (PCR) and screened for mutation by direct DNA sequencing. Variations detected in exon 5 of PITX2 were further evaluated with cloning sequencing. The exon 5 of PITX2 was also sequenced in 100 healthy controls, unrelated to the family, for comparison. Structural models of the wild type and mutant homeodomain of PITX2 were investigated by SWISS-MODEL. RESULTS Affected individuals exhibited variable ocular phenotypes, whereas the systemic anomalies were similar. After direct sequencing and cloning sequencing, a heterozygous deletion/insertion mutation c.198_201delinsTTTCT (p.M66Ifs*133) was revealed in exon 5 of PITX2. This mutation co-segregated with all affected individuals in the family and was not found either in unaffected family members or in 100 unrelated controls. CONCLUSIONS We detected a novel frameshift mutation p.M66Ifs*133 in PITX2 in a Chinese family with ARS. Although PITX2 mutations and polymorphisms have been reported from various ethnic groups, we report for the first time the identification of a novel deletion/insertion mutation that causes frameshift mutation in the homeodomain of PITX2 protein.
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Affiliation(s)
- Hou-fa Yin
- Eye Center, the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009, China
- Zhejiang Provincial Key Lab of Ophthalmology, Hangzhou 310009, China
| | - Xiao-yun Fang
- Eye Center, the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009, China
- Zhejiang Provincial Key Lab of Ophthalmology, Hangzhou 310009, China
| | - Chong-fei Jin
- Eye Center, the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009, China
- Zhejiang Provincial Key Lab of Ophthalmology, Hangzhou 310009, China
| | - Jin-fu Yin
- Eye Center, the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009, China
- Zhejiang Provincial Key Lab of Ophthalmology, Hangzhou 310009, China
| | - Jin-yu Li
- Eye Center, the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009, China
- Zhejiang Provincial Key Lab of Ophthalmology, Hangzhou 310009, China
| | - Su-juan Zhao
- Eye Center, the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009, China
- Zhejiang Provincial Key Lab of Ophthalmology, Hangzhou 310009, China
| | - Qi Miao
- Eye Center, the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009, China
- Zhejiang Provincial Key Lab of Ophthalmology, Hangzhou 310009, China
| | - Feng-wei Song
- Eye Center, the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009, China
- Zhejiang Provincial Key Lab of Ophthalmology, Hangzhou 310009, China
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15
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Abstract
PURPOSE OF REVIEW Anterior segment dysgenesis (ASD) disorders encompass a spectrum of developmental conditions affecting the cornea, iris, and lens and are generally associated with an approximate 50% risk for glaucoma. These conditions are characterized by both autosomal dominant and recessive patterns of inheritance often with incomplete penetrance/variable expressivity. This article summarizes what is known about the genetics of ASD disorders and reviews recent developments. RECENT FINDINGS Mutations in Collagen type IV alpha-1 (COL4A1) and Beta-1,3-galactosyltransferase-like (B3GALTL) have been reported in ASD patients. Novel findings in other well known ocular genes are also presented, among which regulatory region deletions in PAX6 and PITX2 are most notable. SUMMARY Although a number of genetic causes have been identified, many ASD conditions are still awaiting genetic elucidation. The majority of characterized ASD genes encode transcription factors; several other genes represent extracellular matrix-related proteins. All of the involved genes play active roles in ocular development and demonstrate conserved functions across species. The use of novel technologies, such as whole genome sequencing/comparative genomic hybridization, is likely to broaden the mutation spectrums in known genes and assist in the identification of novel causative genes as well as modifiers explaining the phenotypic variability of ASD conditions.
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Dental and Craniofacial Anomalies Associated with Axenfeld-Rieger Syndrome with PITX2 Mutation. Case Rep Med 2010; 2010:621984. [PMID: 20339518 PMCID: PMC2842968 DOI: 10.1155/2010/621984] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2009] [Accepted: 01/11/2010] [Indexed: 11/26/2022] Open
Abstract
Axenfeld-Rieger syndrome (ARS) (OMIM Nr.: 180500) is a rare autosomal dominant disorder (1 : 200000) with genetic and morphologic variability. Glaucoma is associated in 50% of the patients. Craniofacial and dental anomalies are frequently reported with ARS. The present study was designed as a multidisciplinary analysis of orthodontic, ophthalmologic, and genotypical features. A three-generation pedigree was ascertained through a family with ARS. Clinically, radiographic and genetic analyses were performed. Despite an identical genotype in all patients, the phenotype varies in expressivity of craniofacial and dental morphology. Screening for PITX2 and FOXC1 mutations by direct DNA-sequencing revealed a P64L missense mutation in PITX2 in all family members, supporting earlier reports that PITX2 is an essential factor in morphogenesis of teeth and craniofacial skeleton. Despite the fact that the family members had identical mutations, morphologic differences were evident. The concomitant occurrence of rare dental and craniofacial anomalies may be early diagnostic indications of ARS. Early detection of ARS and elevated intraocular pressure (IOP) helps to prevent visual field loss.
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Tümer Z, Bach-Holm D. Axenfeld-Rieger syndrome and spectrum of PITX2 and FOXC1 mutations. Eur J Hum Genet 2009; 17:1527-39. [PMID: 19513095 PMCID: PMC2987033 DOI: 10.1038/ejhg.2009.93] [Citation(s) in RCA: 172] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2008] [Revised: 01/23/2009] [Accepted: 03/17/2009] [Indexed: 01/09/2023] Open
Abstract
Axenfeld-Rieger syndrome (ARS) is a rare autosomal dominant disorder, which encompasses a range of congential malformations affecting the anterior segment of the eye. ARS shows genetic heterogeneity and mutations of the two genes, PITX2 and FOXC1, are known to be associated with the pathogenesis. There are several excellent reviews dealing with the complexity of the phenotype and genotype of ARS. In this study, we will attempt to give a brief review of the clinical features and the relevant diagnostic approaches, together with a detailed review of published PITX2 and FOXC1 mutations.
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Affiliation(s)
- Zeynep Tümer
- The Kennedy Center, Medical Genetics Laboratory, Glostrup, Denmark.
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18
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Riise R, D'haene B, De Baere E, Grønskov K, Brøndum-Nielsen K. Rieger syndrome is not associated with PAX6 deletion: a correction to Acta Ophthalmol Scand 2001: 79: 201-203. Acta Ophthalmol 2009; 87:923. [PMID: 19764918 DOI: 10.1111/j.1755-3768.2009.01696.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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19
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20
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Weisschuh N, Wolf C, Wissinger B, Gramer E. A novel mutation in the FOXC1 gene in a family with Axenfeld-Rieger syndrome and Peters' anomaly. Clin Genet 2008; 74:476-80. [PMID: 18498376 DOI: 10.1111/j.1399-0004.2008.01025.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Peters anomaly and Axenfeld-Rieger syndrome (ARS) belong to the overlapping spectrum of disorders summarized as anterior segment dysgenesis (ASD). Five patients from a family with Peters' anomaly and ARS were screened for mutations in the PITX2, CYP1B1 and FOXC1 genes by direct sequencing. All affected family members examined were heterozygous for a single nucleotide substitution, resulting in a nonsense mutation (Q120X) at a highly conserved residue of the FOXC1 gene that is essential for DNA binding. In this pedigree, all affected family members were diagnosed with ARS except for one who shows bilateral Peters' anomaly. Our findings support the role of FOXC1 mutations in the spectrum of ASD.
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Affiliation(s)
- N Weisschuh
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, University Clinics Tuebingen, Tuebingen, Germany.
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21
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Mossböck G, Faschinger C, Weger M, Renner W. Die Rolle genetischer Faktoren bei den Glaukomen. SPEKTRUM DER AUGENHEILKUNDE 2008. [DOI: 10.1007/s00717-008-0269-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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22
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Meyer-Marcotty P, Weisschuh N, Dressler P, Hartmann J, Stellzig-Eisenhauer A. Morphology of the sella turcica in Axenfeld-Rieger syndrome with PITX2 mutation. J Oral Pathol Med 2008; 37:504-10. [PMID: 18331556 DOI: 10.1111/j.1600-0714.2008.00650.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Axenfeld-Rieger syndrome (ARS) is a rare autosomal dominant disorder with an incidence of 1:200 000. Genotype and phenotype are heterogeneous and clinical morphology impresses with variable expressivity. Additionally to the typical craniofacial and dental aberrations anomalies in the morphology of sella turcica are discussed. METHOD In a multidisciplinary genetic and clinical study four patients of a family with ARS were screened by direct DNA sequencing. Radiographic analysis of the patients was performed for evaluating cranial and dental structures. Additionally, a specific analysis of the morphology of the sella turcica was made on the radiographs. RESULTS Screening for PITX2 and FOXC1 mutations revealed a P64L missense mutation in PITX2 in all four patients. The cephalometric analysis showed a midface hypoplasia associated with a skeletal Class III. All patients showed a sella turcica bridge combined with a prominent posterior clinoid process followed by a steep clivus and an elongated sella turcica. CONCLUSION The incidence of a sella turcica bridge in combination with a PITX2 mutation would suspect that sella turcica anomalies are typical symptoms of the syndrome. Sella turcica anomalies in association with craniofacial and dental aberrations, such as maxillary retrognathia, skeletal Class III relationship and hypoplasia of teeth, might be important indicators for ARS caused by PITX2 mutation.
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Affiliation(s)
- P Meyer-Marcotty
- Department of Orthodontics, Dental Clinic of the Medical Faculty, University of Wuerzburg, Wuerzburg, Germany.
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23
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Matalova E, Fleischmannova J, Sharpe PT, Tucker AS. Tooth agenesis: from molecular genetics to molecular dentistry. J Dent Res 2008; 87:617-23. [PMID: 18573979 DOI: 10.1177/154405910808700715] [Citation(s) in RCA: 128] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Tooth agenesis may originate from either genetic or environmental factors. Genetically determined hypodontic disorders appear as isolated features or as part of a syndrome. Msx1, Pax9, and Axin2 are involved in non-syndromic hypodontia, while genes such as Shh, Pitx2, Irf6, and p63 are considered to participate in syndromic genetic disorders, which include tooth agenesis. In dentistry, artificial tooth implants represent a common solution to tooth loss problems; however, molecular dentistry offers promising solutions for the future. In this paper, the genetic and molecular bases of non-syndromic and syndromic hypodontia are reviewed, and the advantages and disadvantages of tissue engineering in the clinical treatment of tooth agenesis are discussed.
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Affiliation(s)
- E Matalova
- Institute of Animal Physiology and Genetics, Academy of Sciences, Brno, Czech Republic.
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Davis-Silberman N, Ashery-Padan R. Iris development in vertebrates; genetic and molecular considerations. Brain Res 2008; 1192:17-28. [PMID: 17466284 DOI: 10.1016/j.brainres.2007.03.043] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2007] [Revised: 03/11/2007] [Accepted: 03/16/2007] [Indexed: 10/23/2022]
Abstract
The iris plays a key role in visual function. It regulates the amount of light entering the eye and falling on the retina and also operates in focal adjustment of closer objects. The iris is involved in circulation of the aqueous humor and hence functions in regulation of intraocular pressure. Intriguingly, iris pigmented cells possess the ability to transdifferentiate into different ocular cell types of retinal pigmented epithelium, photoreceptors and lens cells. Thus, the iris is considered a potential source for cell-replacement therapies. During embryogenesis, the iris arises from both the optic cup and the periocular mesenchyme. Its interesting mode of development includes specification of the peripheral optic cup to a non-neuronal fate, migration of cells from the surrounding periocular mesenchyme and an atypical formation of smooth muscles from the neuroectoderm. This manner of development raises some interesting general topics concerning the early patterning of the neuroectoderm, the specification and differentiation of diverse cell types and the interactions between intrinsic and extrinsic factors in the process of organogenesis. In this review, we discuss iris anatomy and development, describe major pathologies of the iris and their molecular etiology and finally summarize the recent findings on genes and signaling pathways that are involved in iris development.
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Affiliation(s)
- Noa Davis-Silberman
- Sackler Faculty of Medicine, Department of Human Molecular Genetics and Biochemistry, Tel Aviv University, Ramat Aviv 69978, Tel Aviv, Israel
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Engenheiro E, Saraiva J, Carreira I, Ramos L, Ropers HH, Silva E, Tommerup N, Tümer Z. Cytogenetically invisible microdeletions involving PITX2 in Rieger syndrome. Clin Genet 2007; 72:464-70. [PMID: 17850355 DOI: 10.1111/j.1399-0004.2007.00879.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Axenfeld-Rieger syndrome (ARS) is a genetically heterogeneous autosomal dominant disorder mainly characterized by developmental defects of the anterior segment and extraocular anomalies. ARS shows great clinical variability and encompasses several conditions with overlapping phenotypes, including Rieger syndrome (RS). RS is characterized by developmental defects of the eyes, teeth and umbilicus, and the main causative gene is PITX2 (paired-like homeodomain transcription factor 2, or RIEG1) at 4q25. PITX2 mutations show great variety, from point mutations to microscopic or submicroscopic deletions, and apparently balanced translocations in few cases. We identified cytogenetically undetectable submicroscopic deletions at 4q25 in two unrelated patients diagnosed with RS. One patient had a t(4;17)(q25;q22)dn translocation with a deletion at the 4q breakpoint, and the other patient had an interstitial deletion of 4q25. Both deletions included only the PITX2 and ENPEP (glutamyl aminopeptidase) genes.
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Affiliation(s)
- E Engenheiro
- Department of Cellular and Molecular Medicine, Wilhelm Johannsen Center for Functional Genome Research, University of Copenhagen, Copenhagen, Denmark.
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26
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Abstract
Anterior segment dysgenesis (ASD) is a failure of the normal development of the tissues of the anterior segment of the eye. It leads to anomalies in the structure of the mature anterior segment, associated with an increased risk of glaucoma and corneal opacity. Several different gene mutations have been identified underlying these anomalies with the majority of ASD genes encoding transcriptional regulators. In this review, the role of the ASD genes, PITX2 and FOXC1, is considered in relation to the embryology of the anterior segment, the biochemical function of these proteins, and their role in development and disease aetiology. The emerging view is that these genes act in concert to specify a population of mesenchymal progenitor cells, mainly of neural crest origin, as they migrate anteriorly around the embryonic optic cup. These same genes then regulate mesenchymal cell differentiation to give rise to distinct anterior segment tissues. Development appears critically sensitive to gene dosage, and variation in the normal level of transcription factor activity causes a range of anterior segment anomalies. Interplay between PITX2 and FOXC1 in the development of different anterior segment tissues may partly explain the phenotypic variability and the genetic heterogeneity characteristic of ASD.
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Affiliation(s)
- J C Sowden
- Developmental Biology Unit, University College London Institute of Child Health and Great Ormond Street Hospital for Children NHS Trust, London, UK.
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27
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Martinez-Glez V, Lorda-Sanchez I, Ramirez JM, Ruiz-Barnes P, Rodriguez de Alba M, Diego-Alvarez D, Ramos C, Searby CC, Nishimura DY, Ayuso C. Clinical presentation of a variant of Axenfeld–Rieger syndrome associated with subtelomeric 6p deletion. Eur J Med Genet 2007; 50:120-7. [PMID: 17157569 DOI: 10.1016/j.ejmg.2006.10.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2006] [Accepted: 10/17/2006] [Indexed: 12/20/2022]
Abstract
We report a 22-year-old female with a variant of the Axenfeld-Rieger Syndrome (ARS) and discuss its relation with the subtelomeric 6p deletion. An ARS variant has been described in two familial cases of Axenfeld-Rieger Anomaly (ARA) featuring specific extra ocular manifestations-hypertelorism, midface hypoplasia, mild sensorial deafness, hydrocephaly, psychomotor delay and flattened femoral epiphyses. We proposed that this set of characteristics represents a separate syndrome within the ARS. On the other hand, there have been reported four cases with cryptic de novo pure 6pter microdeletions detected by specific subtelomeric probes in patients with ARS characteristics. We describe a 6pter deletion detected by SNP genotyping and confirmed by FISH and MLPA involving the FOXC1 gene in a patient with ocular and systemic findings that fit perfectly with the variant mentioned above. We conclude that the ARS variant belongs to the ARS phenotypic spectrum, which includes flattened femoral epiphyses as a feature.
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28
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de la Houssaye G, Bieche I, Roche O, Vieira V, Laurendeau I, Arbogast L, Zeghidi H, Rapp P, Halimi P, Vidaud M, Dufier JL, Menasche M, Abitbol M. Identification of the first intragenic deletion of the PITX2 gene causing an Axenfeld-Rieger Syndrome: case report. BMC MEDICAL GENETICS 2006; 7:82. [PMID: 17134502 PMCID: PMC1684248 DOI: 10.1186/1471-2350-7-82] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/10/2006] [Accepted: 11/29/2006] [Indexed: 11/21/2022]
Abstract
BACKGROUND Axenfeld-Rieger syndrome (ARS) is characterized by bilateral congenital abnormalities of the anterior segment of the eye associated with abnormalities of the teeth, midface, and umbilicus. Most cases of ARS are caused by mutations in the genes encoding PITX2 or FOXC1. Here we describe a family affected by a severe form of ARS. CASE PRESENTATION Two members of this family (father and daughter) presented with typical ARS and developed severe glaucoma. The ocular phenotype was much more severe in the daughter than in the father. Magnetic resonance imaging (MRI) detected an aggressive form of meningioma in the father. There was no mutation in the PITX2 gene, determined by exon screening. We identified an intragenic deletion by quantitative genomic PCR analysis and characterized this deletion in detail. CONCLUSION Our findings implicate the first intragenic deletion of the PITX2 gene in the pathogenesis of a severe form of ARS in an affected family. This study stresses the importance of a systematic search for intragenic deletions in families affected by ARS and in sporadic cases for which no mutations in the exons or introns of PITX2 have been found. The molecular genetics of some ARS pedigrees should be re-examined with enzymes that can amplify medium and large genomic fragments.
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Affiliation(s)
- Guillaume de la Houssaye
- Centre de Recherche Thérapeutique en Ophtalmologie, EA n°2502, Faculté de Médecine René Descartes, site Necker, 156 rue de Vaugirard 75730 Paris cedex 15, Université Paris V, Paris, France
| | - Ivan Bieche
- Laboratoire de Génétique Moleculaire-INSERM U745, Faculté des Sciences Pharmaceutiques et Biologiques, Université Paris V, Paris, France
| | - Olivier Roche
- Centre de Recherche Thérapeutique en Ophtalmologie, EA n°2502, Faculté de Médecine René Descartes, site Necker, 156 rue de Vaugirard 75730 Paris cedex 15, Université Paris V, Paris, France
- CHU Necker Enfants Malades, Service d'ophtalmologie, 149, rue de Sèvres 75 Paris cedex 15, France
| | - Véronique Vieira
- Centre de Recherche Thérapeutique en Ophtalmologie, EA n°2502, Faculté de Médecine René Descartes, site Necker, 156 rue de Vaugirard 75730 Paris cedex 15, Université Paris V, Paris, France
| | - Ingrid Laurendeau
- Laboratoire de Génétique Moleculaire-INSERM U745, Faculté des Sciences Pharmaceutiques et Biologiques, Université Paris V, Paris, France
| | - Laurence Arbogast
- Centre de Recherche Thérapeutique en Ophtalmologie, EA n°2502, Faculté de Médecine René Descartes, site Necker, 156 rue de Vaugirard 75730 Paris cedex 15, Université Paris V, Paris, France
| | - Hatem Zeghidi
- CHU Necker Enfants Malades, Service d'ophtalmologie, 149, rue de Sèvres 75 Paris cedex 15, France
| | - Philippe Rapp
- CHU Necker Enfants Malades, Service d'ophtalmologie, 149, rue de Sèvres 75 Paris cedex 15, France
| | - Philippe Halimi
- Service de radiologie et d'imagerie médicale de Hôpital Européen Georges Pompidou, 20-40 Rue Leblanc, 75908 Paris Cedex 15, France
| | - Michel Vidaud
- Laboratoire de Génétique Moleculaire-INSERM U745, Faculté des Sciences Pharmaceutiques et Biologiques, Université Paris V, Paris, France
| | - Jean-Louis Dufier
- Centre de Recherche Thérapeutique en Ophtalmologie, EA n°2502, Faculté de Médecine René Descartes, site Necker, 156 rue de Vaugirard 75730 Paris cedex 15, Université Paris V, Paris, France
- CHU Necker Enfants Malades, Service d'ophtalmologie, 149, rue de Sèvres 75 Paris cedex 15, France
| | - Maurice Menasche
- Centre de Recherche Thérapeutique en Ophtalmologie, EA n°2502, Faculté de Médecine René Descartes, site Necker, 156 rue de Vaugirard 75730 Paris cedex 15, Université Paris V, Paris, France
| | - Marc Abitbol
- Centre de Recherche Thérapeutique en Ophtalmologie, EA n°2502, Faculté de Médecine René Descartes, site Necker, 156 rue de Vaugirard 75730 Paris cedex 15, Université Paris V, Paris, France
- CHU Necker Enfants Malades, Service d'ophtalmologie, 149, rue de Sèvres 75 Paris cedex 15, France
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Maciolek NL, Alward WLM, Murray JC, Semina EV, McNally MT. Analysis of RNA splicing defects in PITX2 mutants supports a gene dosage model of Axenfeld-Rieger syndrome. BMC MEDICAL GENETICS 2006; 7:59. [PMID: 16834779 PMCID: PMC1553432 DOI: 10.1186/1471-2350-7-59] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/03/2006] [Accepted: 07/11/2006] [Indexed: 12/02/2022]
Abstract
BACKGROUND Axenfeld-Rieger syndrome (ARS) is associated with mutations in the PITX2 gene that encodes a homeobox transcription factor. Several intronic PITX2 mutations have been reported in Axenfeld-Rieger patients but their effects on gene expression have not been tested. METHODS We present two new families with recurrent PITX2 intronic mutations and use PITX2c minigenes and transfected cells to address the hypothesis that intronic mutations effect RNA splicing. Three PITX2 mutations have been analyzed: a G>T mutation within the AG 3' splice site (ss) junction associated with exon 4 (IVS4-1G>T), a G>C mutation at position +5 of the 5' (ss) of exon 4 (IVS4+5G>C), and a previously reported A>G substitution at position -11 of 3'ss of exon 5 (IVS5-11A>G). RESULTS Mutation IVS4+5G>C showed 71% retention of the intron between exons 4 and 5, and poorly expressed protein. Wild-type protein levels were proportionally expressed from correctly spliced mRNA. The G>T mutation within the exon 4 AG 3'ss junction shifted splicing exclusively to a new AG and resulted in a severely truncated, poorly expressed protein. Finally, the A>G substitution at position -11 of the 3'ss of exon 5 shifted splicing exclusively to a newly created upstream AG and resulted in generation of a protein with a truncated homeodomain. CONCLUSION This is the first direct evidence to support aberrant RNA splicing as the mechanism underlying the disorder in some patients and suggests that the magnitude of the splicing defect may contribute to the variability of ARS phenotypes, in support of a gene dosage model of Axenfeld-Rieger syndrome.
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Affiliation(s)
- Nicole L Maciolek
- Department of Microbiology and Molecular Genetics, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
| | - Wallace LM Alward
- Department of Ophthalmology, University of Iowa, Iowa City, IA 52242, USA
| | - Jeffrey C Murray
- Department of Pediatrics, University of Iowa, Iowa City, IA 52242, USA
| | - Elena V Semina
- Department of Pediatrics, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
| | - Mark T McNally
- Department of Microbiology and Molecular Genetics, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
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Affiliation(s)
- Minesh Khashu
- Children's and Women's Health Centre of British Columbia, Division of Neonatology, University of Bristish Columbia, Vancouver, BC, Canada
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31
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Abstract
The anterior segment dysgeneses are an ill-defined group of ocular developmental abnormalities that share some common features and have a high prevalence of glaucoma. Current classification of what are and what are not anterior segment dysgeneses seems to vary and our knowledge of them is incomplete. As the limits of classical clinical medicine based on evaluation of signs and symptoms are reached, further advancements increasingly will come from molecular medicine and genetics. In this article we review the normal and abnormal development of the anterior segment (concentrating primarily upon neural crest derived dysgeneses), describe the various clinical entities produced and their diagnosis, and discuss the current knowledge of the genetics of these disorders. We also suggest a new approach to the classification of anterior segment dysgeneses, based upon the embryological contribution to the formation of the anterior segment of the eye.
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Affiliation(s)
- Faisal Idrees
- Institute of Child Health, University College London, UK
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32
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Abstract
Congenital glaucoma is generally related to an iridocorneal angle malformation, with an obstacle to aqueous humor outflow. This spectrum of diseases can involve the angle, the iris and the cornea. The diagnosis relies on characteristic signs and is confirmed by an examination under general anaesthesia and paraclinical examinations (especially echography). An early diagnosis is essential for beginning surgical treatment. Several filtering surgery techniques with equivalent intraocular pressure results are available, but visual function must be protected in all cases. In many cases, genetic counseling relies on a careful clinical analysis and sometimes on a molecular analysis. A number of ocular and/or general abnormalities can be accompanied by glaucoma in infants and children. They must be screened in case of associated signs, but the existence of these abnormalities leads to suspicion of associated glaucoma.
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Affiliation(s)
- P Dureau
- Service d'Ophtalmo-Pédiatrie, Fondation Ophtalmologique Adolphe de Rothschild, Paris.
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33
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Idrees F, Bloch-Zupan A, Free SL, Vaideanu D, Thompson PJ, Ashley P, Brice G, Rutland P, Bitner-Glindzicz M, Khaw PT, Fraser S, Sisodiya SM, Sowden JC. A novel homeobox mutation in the PITX2 gene in a family with Axenfeld-Rieger syndrome associated with brain, ocular, and dental phenotypes. Am J Med Genet B Neuropsychiatr Genet 2006; 141B:184-91. [PMID: 16389592 DOI: 10.1002/ajmg.b.30237] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Axenfeld-Rieger Syndrome (ARS) is a genetically heterogeneous birth defect characterized by malformation of the anterior segment of the eye associated with glaucoma. Mutation of the PITX2 homeobox gene has been identified as a cause of ARS. We report a novel Arg5Trp missense mutation in the PITX2 homeodomain, which is associated with brain abnormalities. One patient had a small sella turcica likely to reflect hypoplasia of the pituitary gland and consistent with the critical role identified for Pitx2 in pituitary development in mice. Two patients had an enlarged cisterna magna, one with a malformed cerebellum, and two had executive skills deficits one in isolation and one in association with a below average intellectual capacity. The mutation caused a typical ARS ocular phenotype. All affected had iris hypoplasia, anterior iris to corneal adhesions, and corectopia. The ocular phenotype varied significantly in severity and showed some asymmetry. All affected also had redundant peri-umbilical skin, a hypoplastic maxilla, microdontia, and hypodontia missing between 20 and 27 teeth with an unusual pattern of tooth loss. Dental phenotypes were documented as they are often poorly characterized in ARS patients. All affected individuals showed an absence of first permanent molars with variable absence of other rarely absent teeth: the permanent upper central incisors, maxillary and mandibular first and second molars, and the mandibular canines. Based on the distinctive dental anomalies, we suggest that the dental phenotype can assist in predicting the presence of a PITX2 mutation and the possibility of brain abnormalities.
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Affiliation(s)
- Faisal Idrees
- Developmental Biology Unit, Institute of Child Health and Great Ormond Street Hospital for Children NHS Trust, University College London, London, United Kingdom
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Stefánsson E. Scientific contributions and citations. ACTA OPHTHALMOLOGICA SCANDINAVICA 2005; 83:275-7. [PMID: 15948776 DOI: 10.1111/j.1600-0420.2005.00504.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
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35
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Maclean K, Smith J, St Heaps L, Chia N, Williams R, Peters GB, Onikul E, McCrossin T, Lehmann OJ, Adès LC. Axenfeld-Rieger malformation and distinctive facial features: Clues to a recognizable 6p25 microdeletion syndrome. Am J Med Genet A 2005; 132A:381-5. [PMID: 15654696 DOI: 10.1002/ajmg.a.30274] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Deletion of distal 6p is associated with a distinctive clinical phenotype including Axenfeld-Rieger malformation, hearing loss, congenital heart disease, dental anomalies, developmental delay, and a characteristic facial appearance. We report the case of a child where recognition of the specific ocular and facial phenotype, led to identification of a 6p microdeletion arising from a de novo 6:18 translocation. Detailed analysis confirmed deletion of the FOXC1 forkhead gene cluster at 6p25. CNS anomalies included hydrocephalus and hypoplasia of the cerebellum, brainstem, and corpus callosum with mild to moderate developmental delay. Unlike previous reports, hearing was normal.
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Affiliation(s)
- Kenneth Maclean
- Department of Clinical Genetics, The Children's Hospital at Westmead, Sydney, New South Wales, Australia.
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Leung AKC, McLeod DR. Autosomal dominant flat umbilicus. Am J Med Genet A 2004; 131:307-9. [PMID: 15523632 DOI: 10.1002/ajmg.a.30395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/01/2023]
Abstract
We describe a Chinese family among whom five members in three generations had a flat umbilicus with vertical and male to male transmission indicative of autosomal dominant inheritance. Except the proband, who also had Tetralogy of Fallot, other affected members had a flat umbilicus as an isolated anomaly. Autosomal dominant transmission of isolated flat umbilicus has not been reported previously.
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Affiliation(s)
- Alexander K C Leung
- Department of Pediatrics, the University of Calgary, Alberta Children's Hospital, Calgary, Alberta T2M 0H5, Canada.
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Karadeniz NN, Kocak-Midillioglu I, Erdogan D, Bökesoy I. Is SHORT syndrome another phenotypic variation of PITX2? Am J Med Genet A 2004; 130A:406-9. [PMID: 15481036 DOI: 10.1002/ajmg.a.30206] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Even though responsible genetic loci and mode of inheritance for the Rieger syndrome have been well established, the mode of inheritance and the genetic basis for SHORT syndrome are still uncertain. The purpose of this paper is to document a familial translocation of t(1;4)(q31.2;q25), in a mother and her son manifesting Rieger syndrome with polycystic ovaries and SHORT syndrome, respectively. It is suggested that these two syndromes may be different expressions of the same gene, PITX2, localized at 4q25. Our patient is the second with the association of Rieger syndrome and polycystic ovaries, and thus this may not be coincidental, moreover insulin resistance-related phenotypes, such as lipodystrophy and polycystic ovaries, can be major component of syndromes with Rieger eye malformation.
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Affiliation(s)
- Pratap Challa
- Duke University Medical Center, Box 3802, Durham, NC 27710, USA
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Wang Y, Zhao H, Zhang X, Feng H. Novel identification of a four-base-pair deletion mutation in PITX2 in a Rieger syndrome family. J Dent Res 2003; 82:1008-12. [PMID: 14630904 DOI: 10.1177/154405910308201214] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Rieger syndrome is one of the most serious causes of tooth agenesis. Mutations in the PITX2, FOXC1, and PAX6 genes have been associated with Rieger syndrome. We have studied a three-generation Chinese family affected with Rieger syndrome and showing prominent dental abnormalities. Mutational screening and sequence analysis of the PITX2 gene revealed a previously unidentified four-base-pair deletion of nucleotides 717-720 in exon 5 in all affected members. The mutation causes a frame shift after Thr44, the 7th amino acid of the homeo-domain, and introduces a premature stop codon in the gene sequence. This deletion is the first unquestionable loss-of-function mutation, deleting all the functionally important parts of the protein. Our novel discovery indicates that the oligodontia and other phenotypes of Rieger syndrome observed in this family are due to this PITX2 mutation, and these data further support the critical role of PIXT2 in tooth morphogenesis.
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Affiliation(s)
- Y Wang
- Department of Prosthodontics, School of Stomatology, Peking University, 22 Zhong Guan Cun Nan Da Jie, Beijing 100081, People's Republic of China
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Abstract
The PAX6 gene is a paradigm for our understanding of the molecular genetics of mammalian eye development. Twelve years after its identification it is one of the most intensively studied genes, both in terms of its diverse and complex functions during oculogenesis and its role in an ever-increasing variety of human congenital eye malformations. The PAX6 field has benefited greatly from the continued input of clinicians, human geneticists and developmental biologists. This review summarizes the latest data on the PAX6 mutation spectrum and recent insights into Pax6 function from the mouse.
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Affiliation(s)
- Isabel M Hanson
- Medical Genetics Section, University of Edinburgh, Molecular Medicine Centre, Western General Hospital, Crewe Road, Edinburgh, EH4 2XU, United Kingdom.
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Abstract
The application of molecular genetic techniques to the study of glaucoma has accelerated greatly during the past few years. In addition to localizing and identifying genes for specific types of glaucoma, researchers have begun to characterize the gene products and investigate molecular mechanisms involved in glaucoma. Much research has been focused on the gene expression, protein processing, and mutations of MYOC/TIGR, which is associated with both juvenile-and adult-onset primary open angle glaucoma. Investigations of other glaucoma-related genes, such as PITX2, FOXC1, and CYP1B1, are enabling a better understanding of anterior segment development and its relation to glaucoma.
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Affiliation(s)
- Darrell WuDunn
- Department of Ophthalmology, Indiana University, Indianapolis, Indiana 46202, USA.
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