1
|
Vetriselvan Y, Manoharan A, Murugan M, Jayakumar S, Govindasamy C, Ravikumar S. In Silico Characterization of Pathogenic Homeodomain Missense Mutations in the PITX2 Gene. Biochem Genet 2024:10.1007/s10528-024-10836-z. [PMID: 38802693 DOI: 10.1007/s10528-024-10836-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Accepted: 05/09/2024] [Indexed: 05/29/2024]
Abstract
Paired homologous domain transcription factor 2 (PITX2) is critically involved in ocular and cardiac development. Mutations in PITX2 are consistently reported in association with Axenfeld-Rieger syndrome, an autosomal dominant genetic disorder and atrial fibrillation, a common cardiac arrhythmia. In this study, we have mined missense mutations in PITX2 gene from NCBI-dbSNP and Ensembl databases, evaluated the pathogenicity of the missense variants in the homeodomain and C-terminal region using five in silico prediction tools SIFT, PolyPhen2, GERP, Mutation Assessor and CADD. Fifteen homeodomain mutations G42V, G42R, R45W, S49Y, R53W, E53D, E55V, R62H, P65S, R69H, G75R, R84G, R86K, R87W, R91P were found to be highly pathogenic by both SIFT, PolyPhen2 were further functionally characterized using I-Mutant 2.0, Consurf, MutPred and Project Hope. The findings of the study can be used for prioritizing mutations in the context of genetic studies.
Collapse
Affiliation(s)
- Yogesh Vetriselvan
- Department of Medical Biotechnology, Aarupadai Veedu Medical College and Hospital, Vinayaka Mission's Research Foundation (DU), Kirumampakkam, Puducherry, 607403, India
| | - Aarthi Manoharan
- Department of Medical Biotechnology, Aarupadai Veedu Medical College and Hospital, Vinayaka Mission's Research Foundation (DU), Kirumampakkam, Puducherry, 607403, India
| | - Manoranjani Murugan
- Department of Medical Biotechnology, Aarupadai Veedu Medical College and Hospital, Vinayaka Mission's Research Foundation (DU), Kirumampakkam, Puducherry, 607403, India
| | - Swetha Jayakumar
- Department of Medical Biotechnology, Aarupadai Veedu Medical College and Hospital, Vinayaka Mission's Research Foundation (DU), Kirumampakkam, Puducherry, 607403, India
| | - Chandramohan Govindasamy
- Department of Community Health Sciences, College of Applied Medical Sciences, King Saud University, P.O. Box 10219, 11433, Riyadh, Saudi Arabia
| | - Sambandam Ravikumar
- Department of Medical Biotechnology, Aarupadai Veedu Medical College and Hospital, Vinayaka Mission's Research Foundation (DU), Kirumampakkam, Puducherry, 607403, India.
| |
Collapse
|
2
|
Cozzitorto C, Peltz Z, Flores LM, Della Santina L, Mao M, Gould DB. Evaluating neural crest cell migration in a Col4a1 mutant mouse model of ocular anterior segment dysgenesis. Cells Dev 2024:203926. [PMID: 38729574 DOI: 10.1016/j.cdev.2024.203926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 05/02/2024] [Accepted: 05/06/2024] [Indexed: 05/12/2024]
Abstract
The periocular mesenchyme (POM) is a transient migratory embryonic tissue derived from neural crest cells (NCCs) and paraxial mesoderm that gives rise to most of the structures in front of the eye. Morphogenetic defects of these structures can impair aqueous humor outflow, leading to elevated intraocular pressure and glaucoma. Mutations in collagen type IV alpha 1 (COL4A1) and alpha 2 (COL4A2) cause Gould syndrome - a multisystem disorder often characterized by variable cerebrovascular, ocular, renal, and neuromuscular manifestations. Approximately one-third of individuals with COL4A1 and COL4A2 mutations have ocular anterior segment dysgenesis (ASD), including congenital glaucoma resulting from abnormalities of POM-derived structures. POM differentiation has been a major focus of ASD research, but the underlying cellular mechanisms are still unclear. Moreover, earlier events including NCC migration and survival defects have been implicated in ASD; however, their roles are not as well understood. Vascular defects are among the most common consequences of COL4A1 and COL4A2 mutations and can influence NCC survival and migration. We therefore hypothesized that NCC migration might be impaired by COL4A1 and COL4A2 mutations. In this study, we used 3D confocal microscopy, gross morphology, and quantitative analyses to test NCC migration in Col4a1 mutant mice. We show that homozygous Col4a1 mutant embryos have severe embryonic growth retardation and lethality, and we identified a potential maternal effect on embryo development. Cerebrovascular defects in heterozygous Col4a1 mutant embryos were present as early as E9.0, showing abnormal cerebral vasculature plexus remodeling compared to controls. We detected abnormal NCC migration within the diencephalic stream and the POM in heterozygous Col4a1 mutants whereby mutant NCCs formed smaller diencephalic migratory streams and POMs. In these settings, migratory NCCs within the diencephalic stream and POM localize farther away from the developing vasculature. Our results show for the first time that Col4a1 mutations lead to cranial NCCs migratory defects in the context of early onset defective angiogenesis without affecting cell numbers, possibly impacting the relation between NCCs and the blood vessels during ASD development.
Collapse
Affiliation(s)
- Corinna Cozzitorto
- Department of Ophthalmology, University of California, San Francisco, CA 94158, United States.
| | - Zoe Peltz
- Department of Ophthalmology, University of California, San Francisco, CA 94158, United States
| | - Lourdes M Flores
- Department of Ophthalmology, University of California, San Francisco, CA 94158, United States
| | - Luca Della Santina
- Department of Ophthalmology, University of California, San Francisco, CA 94158, United States.
| | - Mao Mao
- Department of Ophthalmology, University of California, San Francisco, CA 94158, United States
| | - Douglas B Gould
- Department of Ophthalmology, University of California, San Francisco, CA 94158, United States; Department of Anatomy, Cardiovascular Research Institute, Bakar Aging Research Institute, and Institute for Human Genetics, University of California, San Francisco, United States.
| |
Collapse
|
3
|
Untaroiu A, Reis LM, Higgins BP, Walesa A, Zacharias S, Nikezic D, Costakos DM, Carroll J, Semina EV. In Vivo Assessment of Retinal Phenotypes in Axenfeld-Rieger Syndrome. Invest Ophthalmol Vis Sci 2024; 65:20. [PMID: 38587439 PMCID: PMC11005067 DOI: 10.1167/iovs.65.4.20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Accepted: 03/22/2024] [Indexed: 04/09/2024] Open
Abstract
Purpose Axenfeld-Rieger syndrome (ARS) is characterized by ocular anomalies including posterior embryotoxon, iridocorneal adhesions, corectopia/iris hypoplasia, and developmental glaucoma. Although anterior segment defects and glaucoma contribute to decreased visual acuity, the role of potential posterior segment abnormalities has not been explored. We used high-resolution retinal imaging to test the hypothesis that individuals with ARS have posterior segment pathology. Methods Three individuals with FOXC1-ARS and 10 with PITX2-ARS completed slit-lamp and fundus photography, optical coherence tomography (OCT), OCT angiography, and adaptive optics scanning light ophthalmoscopy (AOSLO). Quantitative metrics were compared to previously published values for individuals with normal vision. Results All individuals demonstrated typical anterior segment phenotypes. Average ganglion cell and inner plexiform layer thickness was lower in PITX2-ARS, consistent with the glaucoma history in this group. A novel phenotype of foveal hypoplasia was noted in 40% of individuals with PITX2-ARS (but none with FOXC1-ARS). Moreover, the depth and volume of the foveal pit were significantly lower in PITX2-ARS compared to normal controls, even excluding individuals with foveal hypoplasia. Analysis of known foveal hypoplasia genes failed to identify an alternative explanation. Foveal cone density was decreased in one individual with foveal hypoplasia and normal in six without foveal hypoplasia. Two individuals (one from each group) demonstrated non-foveal retinal irregularities with regions of photoreceptor anomalies on OCT and AOSLO. Conclusions These findings implicate PITX2 in the development of the posterior segment, particularly the fovea, in humans. The identified posterior segment phenotypes may contribute to visual acuity deficits in individuals with PITX2-ARS.
Collapse
Affiliation(s)
- Ana Untaroiu
- Department of Ophthalmology and Visual Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Linda M. Reis
- Department of Ophthalmology and Visual Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Brian P. Higgins
- Department of Ophthalmology and Visual Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Ashleigh Walesa
- Department of Ophthalmology and Visual Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Serena Zacharias
- School of Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Danica Nikezic
- Department of Ophthalmology and Visual Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Deborah M. Costakos
- Department of Ophthalmology and Visual Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Joseph Carroll
- Department of Ophthalmology and Visual Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Elena V. Semina
- Department of Ophthalmology and Visual Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
- Department of Pediatrics and Children's Research Institute, Medical College of Wisconsin and Childrens Wisconsin, Milwaukee, Wisconsin, United States
| |
Collapse
|
4
|
Zhang L, Tie X, Che F, Wang G, Ge Y, Li B, Yang Y. Novel maternal duplication of 6p22.3-p25.3 with subtelomeric 6p25.3 deletion: new clinical findings and genotype-phenotype correlations. Mol Cytogenet 2023; 16:11. [PMID: 37303060 DOI: 10.1186/s13039-023-00640-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 05/24/2023] [Indexed: 06/13/2023] Open
Abstract
BACKGROUND Copy-number variants (CNVs) drive many neurodevelopmental-related disorders. Although many neurodevelopmental-related CNVs can give rise to widespread phenotypes, it is necessary to identify the major genes contributing to phenotypic presentation. Copy-number variations in chromosome 6, such as independent 6p deletion and 6p duplication, have been reported in several live-born infants and present widespread abnormalities such as intellectual disability, growth deficiency, developmental delay, and multiple dysmorphic facial features. However, a contiguous deletion and duplication in chromosome 6p regions have been reported in only a few cases. CASE PRESENTATION In this study, we reported the first duplication of chromosome band 6p25.3-p22.3 with deletion of 6p25.3 in a pedigree. This is the first case reported involving CNVs in these chromosomal regions. In this pedigree, we reported a 1-year-old boy with maternal 6p25-pter duplication characterized by chromosome karyotype. Further analysis using CNV-seq revealed a 20.88-Mb duplication at 6p25.3-p22.3 associated with a contiguous 0.66-Mb 6p25.3 deletion. Whole exome sequencing confirmed the deletion/duplication and identified no pathogenic or likely pathogenic variants related with the patient´s phenotype. The proband presented abnormal growth, developmental delay, skeletal dysplasia, hearing loss, and dysmorphic facial features. Additionally, he presented recurrent infection after birth. CNV-seq using the proband´s parental samples showed that the deletion/duplication was inherited from the proband´s mother, who exhibited a similar phenotype to the proband. When compared with other cases, this proband and his mother presented a new clinical finding: forearm bone dysplasia. The major candidate genes contributing to recurrent infection, eye development, hearing loss features, neurodevelopmental development, and congenital bone dysplasia were further discussed. CONCLUSIONS Our results showed a new clinical finding of a contiguous deletion and duplication in chromosome 6p regions and suggested candidate genes associated with phenotypic features, such as FOXC1, SERPINB6, NRN1, TUBB2A, IRF4, and RIPK1.
Collapse
Affiliation(s)
- Liyu Zhang
- Shaanxi Institute for Pediatric Diseases, Xi'an Children's Hospital, Xi'an, China
| | - Xiaoling Tie
- Department of Rehabilitation, Xi'an Children's Hospital, Xi'an, China
| | - Fengyu Che
- Shaanxi Institute for Pediatric Diseases, Xi'an Children's Hospital, Xi'an, China
| | - Guoxia Wang
- Shaanxi Institute for Pediatric Diseases, Xi'an Children's Hospital, Xi'an, China
| | - Ying Ge
- The Center Laboratory Medicine, Xi'an Children's Hospital, Xi'an, China
| | - Benchang Li
- Shaanxi Institute for Pediatric Diseases, Xi'an Children's Hospital, Xi'an, China
| | - Ying Yang
- Shaanxi Institute for Pediatric Diseases, Xi'an Children's Hospital, Xi'an, China.
| |
Collapse
|
5
|
Cheng L, Zhang Y, Ding Y, Yuan Z, Han X. The clinical and genetic findings in a Chinese family with Axenfeld-Rieger syndrome. Heliyon 2022; 8:e12543. [PMID: 36619412 PMCID: PMC9813731 DOI: 10.1016/j.heliyon.2022.e12543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 11/05/2022] [Accepted: 12/14/2022] [Indexed: 12/26/2022] Open
Abstract
Objecive To describe the clinical and genetic findings of an Axenfeld-Rieger syndrome (ARS) family with a new PITX2 splicing mutation. Methods A Chinese ARS family with five affected individuals was recruited. Exome sequencing was performed on the proband and the variant (C.253-9C > A) in PITX2 gene was detected as a pathogenic mutation. Sanger sequencing was performed for verification and cosegregation analysis. Real-time polymerase chain reaction (RT- PCR) and Western blotting were performed to verify the expression of the pathogenic gene. Results All the patients showed abnormalities in the anterior segment of both eyes including posterior embryotoxon, corectopia, iris dysplasia, and iridocorneal tissue adhesions. In addition, they all presented systemic features, including maxillary hypoplasia, underbite, hypodontia, conical teeth. Only III-7 showed obvious umbilical skin. In the PITX2 family, we identified a novel heterozygous splicing mutation (C.253-9C > A) which was confirmed by Sanger sequencing to be completely cosegregated with the ARS phenotype. Real-time quantitative PCR and Western results showed that PITX2 mRNA and protein expression were significantly lower in patients compared with unrelated normal controls. Conclusion In the ARS pedigree, we summarized the variable phenotype, described a novel PITX2 splicing mutation which expand the genetic spectrum of ARS. We further confirmed the possibility of development of ARS induced by this PITX2 gene deficiency.
Collapse
Affiliation(s)
- Lingyan Cheng
- Department of Ophthalmology, The Affiliated Wuxi No. 2 People's Hospital of Nanjing Medical University, No. 68 Zhongshan Road, Wuxi, Jiangsu, 214000, People's republic of China
| | - Yinong Zhang
- Department of Ophthalmology, The Affiliated Wuxi No. 2 People's Hospital of Nanjing Medical University, No. 68 Zhongshan Road, Wuxi, Jiangsu, 214000, People's republic of China
| | - Yuzhi Ding
- Department of Ophthalmology, Zhongda Hospital Southeast University, No. 87 Dingjiaqiao, Nanjing, Jiangsu, 210000, People's republic of China
| | - Zhilan Yuan
- Department of Ophthalmology, Jiangsu Province Hospital and Nanjing Medical University First Affiliated Hospital, No. 300 Guangzhou Road, Nanjing, Jiangsu, 210029, People's republic of China
| | - Xiao Han
- Key Laboratory of Human Functional Genomics of Jiangsu Province, Nanjing Medical University, No. 818 Tianyuan Road, Nanjing, Jiangsu, 211166, People's republic of China,Corresponding author.
| |
Collapse
|
6
|
Prem Senthil M, Knight LSW, Taranath D, Mackey DA, Ruddle JB, Chiang MY, Siggs OM, Souzeau E, Craig JE. Comparison of Anterior Segment Abnormalities in Individuals With FOXC1 and PITX2 Variants. Cornea 2022; 41:1009-1015. [PMID: 35354164 PMCID: PMC9390227 DOI: 10.1097/ico.0000000000003020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 01/14/2022] [Accepted: 01/31/2022] [Indexed: 11/30/2022]
Abstract
PURPOSE Axenfeld-Rieger syndrome encompasses a group of developmental disorders affecting the anterior chamber structures of the eye, with associated systemic features in some cases. This study aims to compare the difference in anterior segment phenotypes such as those involving the cornea, iris, lens, and anterior chamber angle between cases with disease-causing sequence variations in FOXC1 and PITX2 . METHODS This cross-sectional study involved 61 individuals, from 32 families with pathogenic FOXC1 or PITX2 variants, who were registered with the Australian and New Zealand Registry of Advanced Glaucoma. RESULTS The median age of the cohort was 39 years at the time of last assessment (range 3-85 years; females, 54%). Thirty-two patients had pathogenic variants in the FOXC1 gene, and 29 patients had pathogenic variants in the PITX2 gene. Corneal abnormalities were more common in individuals with FOXC1 variants (18/36, 50%) than those with PITX2 variants (4/25, 16%; P = 0.007). Iris abnormalities such as hypoplasia ( P = 0.008) and pseudopolycoria ( P = 0.001) were more common in individuals with PITX2 variants than those with FOXC1 variants. Glaucoma was present in 72% of participants. Corneal decompensation was positively associated with corneal abnormalities ( P < 0.001), glaucoma surgery ( P = 0.025), and cataract surgery ( P = 0.002). CONCLUSIONS Corneal abnormalities were more common in individuals with FOXC1 than in those with PITX2 variants and were often associated with early onset glaucoma. These findings highlight that patients with FOXC1 variations require close follow-up and monitoring throughout infancy and into adulthood.
Collapse
Affiliation(s)
- Mallika Prem Senthil
- Caring Futures Institute, College of Nursing and Health Sciences, Flinders University, Adelaide, South Australia, Australia
| | - Lachlan S. W. Knight
- Department of Ophthalmology, Flinders University, Flinders Medical Centre, Adelaide, South Australia, Australia
| | - Deepa Taranath
- Department of Ophthalmology, Flinders University, Flinders Medical Centre, Adelaide, South Australia, Australia
| | - David A. Mackey
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Tasmania, Australia
- Centre for Ophthalmology and Visual Science and Lions Eye Institute, University of Western Australia, Perth, Australia
| | - Jonathan B. Ruddle
- Department of Ophthalmology, Royal Children's Hospital, Melbourne, Australia
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Australia
- Department of Surgery, University of Melbourne, Melbourne, Australia
| | - Mark Y. Chiang
- Queensland Children's Hospital, South Brisbane, Queensland, Australia; and
- University of Queensland, Brisbane, Queensland, Australia
| | - Owen M. Siggs
- Department of Ophthalmology, Flinders University, Flinders Medical Centre, Adelaide, South Australia, Australia
| | - Emmanuelle Souzeau
- Department of Ophthalmology, Flinders University, Flinders Medical Centre, Adelaide, South Australia, Australia
| | - Jamie E. Craig
- Department of Ophthalmology, Flinders University, Flinders Medical Centre, Adelaide, South Australia, Australia
| |
Collapse
|
7
|
Duester G. Towards a Better Vision of Retinoic Acid Signaling during Eye Development. Cells 2022; 11:cells11030322. [PMID: 35159132 PMCID: PMC8834304 DOI: 10.3390/cells11030322] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 01/11/2022] [Accepted: 01/17/2022] [Indexed: 02/01/2023] Open
Abstract
Retinoic acid (RA) functions as an essential signal for development of the vertebrate eye by controlling the transcriptional regulatory activity of RA receptors (RARs). During eye development, the optic vesicles and later the retina generate RA as a metabolite of vitamin A (retinol). Retinol is first converted to retinaldehyde by retinol dehydrogenase 10 (RDH10) and then to RA by all three retinaldehyde dehydrogenases (ALDH1A1, ALDH1A2, and ALDH1A3). In early mouse embryos, RA diffuses to tissues throughout the optic placode, optic vesicle, and adjacent mesenchyme to stimulate folding of the optic vesicle to form the optic cup. RA later generated by the retina is needed for further morphogenesis of the optic cup and surrounding perioptic mesenchyme; loss of RA at this stage leads to microphthalmia and cornea plus eyelid defects. RA functions by binding to nuclear RARs at RA response elements (RAREs) that either activate or repress transcription of key genes. Binding of RA to RARs regulates recruitment of transcriptional coregulators such as nuclear receptor coactivator (NCOA) or nuclear receptor corepressor (NCOR), which in turn control binding of the generic coactivator p300 or the generic corepressor PRC2. No genes have been identified as direct targets of RA signaling during eye development, so future studies need to focus on identifying such genes and their RAREs. Studies designed to learn how RA normally controls eye development in vivo will provide basic knowledge valuable for determining how developmental eye defects occur and for improving strategies to treat eye defects.
Collapse
Affiliation(s)
- Gregg Duester
- Development, Aging, and Regeneration Program, Sanford Burnham Prebys Medical Discovery Institute, 10901 N. Torrey Pines Road, La Jolla, CA 92037, USA
| |
Collapse
|
8
|
Wawrocka A, Walczak-Sztulpa J, Socha M, Kuszel L, Sowinska-Seidler A, Budny B, Bukowska-Olech E, Pilas-Pomykalska M, Jamsheer A, Krawczynski MR. Homozygous microdeletion in the 11p13 region in the patient with isolated form of aniridia: New challenges in the genetic diagnostics of aniridia. Am J Med Genet A 2021; 188:642-647. [PMID: 34773354 DOI: 10.1002/ajmg.a.62559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 10/13/2021] [Accepted: 10/22/2021] [Indexed: 11/09/2022]
Abstract
Aniridia is usually an autosomal dominant, rare disorder characterized by a variable degree of hypoplasia or the absence of iris tissue, with additional ocular abnormalities. Pathogenic variants in the PAX6 gene are associated with aniridia in most patients. However, in up to 30% of individuals, disease results from 11p13 chromosomal rearrangements. Here we present a patient with a clinical diagnosis of partial aniridia born to consanguineous Polish parents. The parents were asymptomatic and ophthalmologically normal. We performed PAX6 sequencing, array comparative genomic hybridization, quantitative real-time PCR, and whole genome sequencing. aCGH revealed a homozygous deletion of the DCDC1 gene fragment in the patient. The same, but heterozygous deletion, was detected in each of the patient's asymptomatic parents and brother. In the presented family, the signs and symptoms of aniridia are observed only in the homozygous proband. Whole genome sequencing analysis was performed to determine other possible causes of the disease and did not detect any additional or alternative potentially pathogenic variant. We report a novel homozygous deletion located in the 11p13 region, which does not include the PAX6 gene or any known PAX6 enhancers. To our best knowledge, this is the first reported case of a patient presented with isolated aniridia carrying a homozygous microdeletion downstream of the PAX6 gene.
Collapse
Affiliation(s)
- Anna Wawrocka
- Department of Medical Genetics, Poznan University of Medical Sciences, Poznan, Poland
| | | | - Magdalena Socha
- Department of Medical Genetics, Poznan University of Medical Sciences, Poznan, Poland
| | - Lukasz Kuszel
- Department of Medical Genetics, Poznan University of Medical Sciences, Poznan, Poland
| | - Anna Sowinska-Seidler
- Department of Medical Genetics, Poznan University of Medical Sciences, Poznan, Poland
| | - Bartlomiej Budny
- Department of Endocrinology, Metabolism and Internal Medicine, Poznan University of Medical Sciences, Poznan, Poland
| | | | | | - Aleksander Jamsheer
- Department of Medical Genetics, Poznan University of Medical Sciences, Poznan, Poland.,Centers for Medical Genetics GENESIS, Poznan, Poland
| | - Maciej R Krawczynski
- Department of Medical Genetics, Poznan University of Medical Sciences, Poznan, Poland.,Centers for Medical Genetics GENESIS, Poznan, Poland
| |
Collapse
|
9
|
Li K, Tang M, Xu M, Yu Y. A novel missense mutation of FOXC1 in an Axenfeld-Rieger syndrome patient with a congenital atrial septal defect and sublingual cyst: a case report and literature review. BMC Med Genomics 2021; 14:255. [PMID: 34715865 PMCID: PMC8555356 DOI: 10.1186/s12920-021-01103-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 10/18/2021] [Indexed: 12/04/2022] Open
Abstract
Background Axenfeld–Rieger syndrome (ARS) is a rare autosomal dominant hereditary disease characterized primarily by maldevelopment of the anterior segment of both eyes, accompanied by developmental glaucoma, and other congenital anomalies. FOXC1 and PITX2 genes play important roles in the development of ARS. Case presentation The present report describes a 7-year-old boy with iris dysplasia, displaced pupils, and congenital glaucoma in both eyes. The patient presented with a congenital atrial septal defect and sublingual cyst. The patient’s family has no clinical manifestations. Next generation sequencing identified a pathogenic heterozygous missense variant in FOXC1 gene (NM_001453:c. 246C>A, p. S82R) in the patient. Sanger sequencing confirmed this result, and this mutation was not detected in the other three family members. Conclusion To the best of our knowledge, the results of our study reveal a novel mutation in the FOXC1 gene associated with ARS.
Collapse
Affiliation(s)
- Kaiming Li
- Affiliated Hospital of Southwest Medical University, No.25, Taiping Street, Jiangyang District, Luzhou City, 646000, Sichuan Province, China
| | - Min Tang
- Affiliated Hospital of Southwest Medical University, No.25, Taiping Street, Jiangyang District, Luzhou City, 646000, Sichuan Province, China
| | - Manhua Xu
- Affiliated Hospital of Southwest Medical University, No.25, Taiping Street, Jiangyang District, Luzhou City, 646000, Sichuan Province, China
| | - Yinggui Yu
- Affiliated Hospital of Southwest Medical University, No.25, Taiping Street, Jiangyang District, Luzhou City, 646000, Sichuan Province, China.
| |
Collapse
|
10
|
Flach H, Basten T, Schreiner C, Dietmann P, Greco S, Nies L, Roßmanith N, Walter S, Kühl M, Kühl SJ. Retinol binding protein 1 affects Xenopus anterior neural development via all-trans retinoic acid signaling. Dev Dyn 2021; 250:1096-1112. [PMID: 33570783 DOI: 10.1002/dvdy.313] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 01/30/2021] [Accepted: 02/03/2021] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Retinol binding protein 1 (Rbp1) acts as an intracellular regulator of vitamin A metabolism and retinoid transport. In mice, Rbp1 deficiency decreases the capacity of hepatic stellate cells to take up all-trans retinol and sustain retinyl ester stores. Furthermore, Rbp1 is crucial for visual capacity. Although the function of Rbp1 has been studied in the mature eye, its role during early anterior neural development has not yet been investigated in detail. RESULTS We showed that rbp1 is expressed in the eye, anterior neural crest cells (NCCs) and prosencephalon of the South African clawed frog Xenopus laevis. Rbp1 knockdown led to defects in eye formation, including microphthalmia and disorganized retinal lamination, and to disturbed induction and differentiation of the eye field, as shown by decreased rax and pax6 expression. Furthermore, it resulted in reduced rax expression in the prosencephalon and affected cranial cartilage. Rbp1 inhibition also interfered with neural crest induction and migration, as shown by twist and slug. Moreover, it led to a significant reduction of the all-trans retinoic acid target gene pitx2 in NCC-derived periocular mesenchyme. The Rbp1 knockdown phenotypes were rescued by pitx2 RNA co-injection. CONCLUSION Rbp1 is crucial for the development of the anterior neural tissue.
Collapse
Affiliation(s)
- Hannah Flach
- Institute of Biochemistry and Molecular Biology, Ulm University, Ulm, Germany
| | - Thomas Basten
- Institute of Biochemistry and Molecular Biology, Ulm University, Ulm, Germany
| | - Corinna Schreiner
- Institute of Biochemistry and Molecular Biology, Ulm University, Ulm, Germany
| | - Petra Dietmann
- Institute of Biochemistry and Molecular Biology, Ulm University, Ulm, Germany
| | - Sara Greco
- Institute of Biochemistry and Molecular Biology, Ulm University, Ulm, Germany
| | - Lea Nies
- Institute of Biochemistry and Molecular Biology, Ulm University, Ulm, Germany
| | - Nathalie Roßmanith
- Institute of Biochemistry and Molecular Biology, Ulm University, Ulm, Germany
| | - Svenja Walter
- Institute of Biochemistry and Molecular Biology, Ulm University, Ulm, Germany
| | - Michael Kühl
- Institute of Biochemistry and Molecular Biology, Ulm University, Ulm, Germany
| | - Susanne J Kühl
- Institute of Biochemistry and Molecular Biology, Ulm University, Ulm, Germany
| |
Collapse
|
11
|
Souzeau E, Siggs OM, Pasutto F, Knight LSW, Perez‐Jurado LA, McGregor L, Le Blanc S, Barnett CP, Liebelt J, Craig JE. Gene-specific facial dysmorphism in Axenfeld-Rieger syndrome caused by FOXC1 and PITX2 variants. Am J Med Genet A 2021; 185:434-439. [PMID: 33231930 PMCID: PMC7839469 DOI: 10.1002/ajmg.a.61982] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 10/26/2020] [Accepted: 10/31/2020] [Indexed: 01/29/2023]
Abstract
Axenfeld-Rieger syndrome is a genetic condition characterized by ocular and systemic features and is most commonly caused by variants in the FOXC1 or PITX2 genes. Facial dysmorphism is part of the syndrome but the differences between both genes have never been systematically assessed. Here, 11 facial traits commonly reported in Axenfeld-Rieger syndrome were assessed by five clinical geneticists blinded to the molecular diagnosis. Individuals were drawn from the Australian and New Zealand Registry of Advanced Glaucoma in Australia or recruited through the Genetic and Ophthalmology Unit of l'Azienda Socio-Sanitaria Territoriale Grande Ospedale Metropolitano Niguarda in Italy. Thirty-four individuals from 18 families were included. FOXC1 variants were present in 64.7% of individuals and PITX2 variants in 35.3% of individuals. A thin upper lip (55.9%) and a prominent forehead (41.2%) were common facial features shared between both genes. Hypertelorism/telecanthus (81.8% vs 25.0%, p = 0.002) and low-set ears (31.8% vs 0.0%, p = 0.036) were significantly more prevalent in individuals with FOXC1 variants compared with PITX2 variants. These findings may assist clinicians in reaching correct clinical and molecular diagnoses, and providing appropriate genetic counseling.
Collapse
Affiliation(s)
- Emmanuelle Souzeau
- Department of OphthalmologyFlinders University, Flinders Medical CentreAdelaideSouth AustraliaAustralia
| | - Owen M. Siggs
- Department of OphthalmologyFlinders University, Flinders Medical CentreAdelaideSouth AustraliaAustralia
| | - Francesca Pasutto
- Institute of Human GeneticsFriedrich‐Alexander‐Universität Erlangen‐NürnbergErlangenGermany
| | - Lachlan S. W. Knight
- Department of OphthalmologyFlinders University, Flinders Medical CentreAdelaideSouth AustraliaAustralia
| | - Luis A. Perez‐Jurado
- Paediatric and Reproductive Genetics UnitWomen's and Children's HospitalAdelaideSouth AustraliaAustralia
- South Australia Health and Medical Research InstituteThe University of AdelaideAdelaideSouth AustraliaAustralia
- Genetics Unit, Universitat Pompeu FabraHospital del Mar Research Institute (IMIM) and CIBERERBarcelonaSpain
| | - Lesley McGregor
- Paediatric and Reproductive Genetics UnitWomen's and Children's HospitalAdelaideSouth AustraliaAustralia
| | - Shannon Le Blanc
- Paediatric and Reproductive Genetics UnitWomen's and Children's HospitalAdelaideSouth AustraliaAustralia
| | - Christopher P. Barnett
- Paediatric and Reproductive Genetics UnitWomen's and Children's HospitalAdelaideSouth AustraliaAustralia
| | - Jan Liebelt
- Paediatric and Reproductive Genetics UnitWomen's and Children's HospitalAdelaideSouth AustraliaAustralia
| | - Jamie E. Craig
- Department of OphthalmologyFlinders University, Flinders Medical CentreAdelaideSouth AustraliaAustralia
| |
Collapse
|
12
|
Li Y, Zhang J, Dai Y, Fan Y, Xu J. Novel Mutations in COL6A3 That Associated With Peters' Anomaly Caused Abnormal Intracellular Protein Retention and Decreased Cellular Resistance to Oxidative Stress. Front Cell Dev Biol 2020; 8:531986. [PMID: 33304895 PMCID: PMC7693641 DOI: 10.3389/fcell.2020.531986] [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: 02/02/2020] [Accepted: 09/22/2020] [Indexed: 11/13/2022] Open
Abstract
Peters' anomaly (PA) is a rare form of anterior segment dysgenesis characterized by central corneal opacity accompanied by iridocorneal or lenticulo-corneal adhesions. Although genetic mutations, particularly those affecting transcription factors that function in eye development, are known to cause PA, the etiology of this disease remains poorly understood. In this study, 23 patients with PA were recruited for panel sequencing. Four out of 23 patients were found to carry variants in known PA causal genes, PITX2 and PITX3. More importantly, two homozygous mutations (NM_057164: p.Val86Ala and p.Arg689Cys) in the COL6A3 gene (collagen type VI alpha-3 chain) that correlated with the phenotype of type I PA were identified, and then validated by following whole-exome sequencing. The expression profile of the COL6A3 gene in the cornea and the impact of the mutations on protein physiological processing and cellular function were further explored. It was shown that COL6A3 presented relatively high expression in the cornea. The mutant COL6A3 protein was relatively retained intracellularly, and its expression reduced cellular resistance to oxidative stress through an enhanced endoplasmic reticulum stress response. Taken together, our findings expanded the known genetic spectrum of PA, and provided evidence for the involvement of COL6A3 or collagen VI in ocular anterior segment development, thereby offering new insight for future investigations targeting PA.
Collapse
Affiliation(s)
- Yue Li
- Eye Institute and Department of Ophthalmology, Eye and ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
| | - Jing Zhang
- Eye Institute and Department of Ophthalmology, Eye and ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
| | - Yiqin Dai
- Eye Institute and Department of Ophthalmology, Eye and ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
| | - Yidan Fan
- Eye Institute and Department of Ophthalmology, Eye and ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
| | - Jianjiang Xu
- Eye Institute and Department of Ophthalmology, Eye and ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
| |
Collapse
|
13
|
FOXC1 variant in a family with anterior segment dysgenesis and normal-tension glaucoma. Exp Eye Res 2020; 200:108220. [PMID: 32905845 DOI: 10.1016/j.exer.2020.108220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 08/21/2020] [Accepted: 09/03/2020] [Indexed: 11/21/2022]
Abstract
Our study describes the glaucoma phenotype in a family with Axenfeld-Rieger syndrome (ARS) and a FOXC1 variant. Included were 20 subjects from a large three generation family of Jewish Indian ancestry. Subjects underwent a comprehensive ophthalmic examination including automated perimetry and optical coherence tomography. Eight subjects were available for molecular analysis which included whole genome sequencing on selected patients and Sanger sequencing for variant screening. Eleven patients demonstrated a wide spectrum of Axenfeld-Rieger anomaly signs and symptoms. These ranged from subtle angle abnormalities to remarkable anterior segment abnormalities such as corectopia, iris adhesions and strands. Among them, six had glaucoma and two were glaucoma suspects. Of the six subjects with glaucoma three had high-tension glaucoma and two had normal-tension glaucoma. Molecular analysis revealed a previously described pathogenic variant in the FOXC1 gene (c.378C > G p.I126M; rs104893958), in six affected patients which was not identified in two healthy siblings. Molecular analysis also revealed a PITX2 missense variant (c.28T > A p.L10M; rs755864040) which did not segregate with clinical findings and was considered likely benign. In conclusion, patients with ARS due to FOXC1 variants may present with glaucomatous optic nerve damage without apparent elevation in IOP. Normal-tension glaucoma is less commonly reported in individuals with ARS and a comprehensive glaucoma assessment may be warranted in these individuals even with normal IOP. These findings raise the possibility that glaucomatous damage associated with FOXC1 is not only due to high IOP.
Collapse
|
14
|
Zhang Q, Liang D, Yue Y, He L, Li N, Jiang D, Hu P, Zhao Q. Axenfeld-Rieger syndrome-associated mutants of the transcription factor FOXC1 abnormally regulate NKX2-5 in model zebrafish embryos. J Biol Chem 2020; 295:11902-11913. [PMID: 32631953 DOI: 10.1074/jbc.ra120.013287] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 07/04/2020] [Indexed: 12/25/2022] Open
Abstract
FOXC1 is a member of the forkhead family of transcription factors, and whose function is poorly understood. A variety of FOXC1 mutants have been identified in patients diagnosed with the autosomal dominant disease Axenfeld-Rieger syndrome, which is mainly characterized by abnormal development of the eyes, particularly those who also have accompanying congenital heart defects (CHD). However, the role of FOXC1 in CHD, and how these mutations might impact FOXC1 function, remains elusive. Our previous work provided one clue to possible function, demonstrating that zebrafish foxc1a, an orthologue of human FOXC1 essential for heart development, directly regulates the expression of nkx2.5, encoding a transcriptional regulator of cardiac progenitor cells. Abnormal expression of Nkx2-5 leads to CHD in mice and is also associated with CHD patients. Whether this link extends to the human system, however, requires investigation. In this study, we demonstrate that FOXC1 does regulate human NKX2-5 expression in a dose-dependent manner via direct binding to its proximal promoter. A comparison of FOXC1 mutant function in the rat cardiac cell line H9c2 and zebrafish embryos suggested that the zebrafish embryos might serve as a more representative model system than the H9c2 cells. Finally, we noted that three of the Axenfeld-Rieger syndrome FOXC1 mutations tested increased, whereas a fourth repressed the expression of NKX2-5 These results imply that mutant FOXC1s might play etiological roles in CHD by abnormally regulating NKX2-5 in the patients. And zebrafish embryos can serve as a useful in vivo platform for rapidly evaluating disease-causing roles of mutated genes.
Collapse
Affiliation(s)
- Qinxin Zhang
- MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Nanjing, China
| | - Dong Liang
- Department of Prenatal Diagnosis, Obstetrics and Gynecology Hospital Affiliated to Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Nanjing, China
| | - Yunyun Yue
- School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Luqingqing He
- MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Nanjing, China
| | - Nan Li
- MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Nanjing, China
| | - Dongya Jiang
- MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Nanjing, China
| | - Ping Hu
- Department of Prenatal Diagnosis, Obstetrics and Gynecology Hospital Affiliated to Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Nanjing, China
| | - Qingshun Zhao
- MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Nanjing, China
| |
Collapse
|
15
|
Childhood glaucoma genes and phenotypes: Focus on FOXC1 mutations causing anterior segment dysgenesis and hearing loss. Exp Eye Res 2019; 190:107893. [PMID: 31836490 DOI: 10.1016/j.exer.2019.107893] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 10/16/2019] [Accepted: 12/04/2019] [Indexed: 12/27/2022]
Abstract
Childhood glaucoma is an important cause of blindness world-wide. Eleven genes are currently known to cause inherited forms of glaucoma with onset before age 20. While all the early-onset glaucoma genes cause severe disease, considerable phenotypic variability is observed among mutations carriers. In particular, FOXC1 genetic variants are associated with a broad range of phenotypes including multiple forms of glaucoma and also systemic abnormalities, especially hearing loss. FOXC1 is a member of the forkhead family of transcription factors and is involved in neural crest development necessary for formation of anterior eye structures and also pharyngeal arches that form the middle ear bones. In this study we review the clinical phenotypes reported for known FOXC1 mutations and show that mutations in patients with reported ocular anterior segment abnormalities and hearing loss primarily disrupt the critically important forkhead domain. These results suggest that optimal care for patients affected with anterior segment dysgenesis should include screening for FOXC1 mutations and also testing for hearing loss.
Collapse
|
16
|
Seifi M, Walter MA. Accurate prediction of functional, structural, and stability changes in PITX2 mutations using in silico bioinformatics algorithms. PLoS One 2018; 13:e0195971. [PMID: 29664915 PMCID: PMC5903617 DOI: 10.1371/journal.pone.0195971] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 04/03/2018] [Indexed: 11/24/2022] Open
Abstract
Mutations in PITX2 have been implicated in several genetic disorders, particularly Axenfeld-Rieger syndrome. In order to determine the most reliable bioinformatics tools to assess the likely pathogenicity of PITX2 variants, the results of bioinformatics predictions were compared to the impact of variants on PITX2 structure and function. The MutPred, Provean, and PMUT bioinformatic tools were found to have the highest performance in predicting the pathogenicity effects of all 18 characterized missense variants in PITX2, all with sensitivity and specificity >93%. Applying these three programs to assess the likely pathogenicity of 13 previously uncharacterized PITX2 missense variants predicted 12/13 variants as deleterious, except A30V which was predicted as benign variant for all programs. Molecular modeling of the PITX2 homoedomain predicts that of the 31 known PITX2 variants, L54Q, F58L, V83F, V83L, W86C, W86S, and R91P alter PITX2's structure. In contrast, the remaining 24 variants are not predicted to change PITX2's structure. The results of molecular modeling, performed on all the PITX2 missense mutations located in the homeodomain, were compared with the findings of eight protein stability programs. CUPSAT was found to be the most reliable in predicting the effect of missense mutations on PITX2 stability. Our results showed that for PITX2, and likely other members of this homeodomain transcription factor family, MutPred, Provean, PMUT, molecular modeling, and CUPSAT can reliably be used to predict PITX2 missense variants pathogenicity.
Collapse
Affiliation(s)
- Morteza Seifi
- Department of Medical Genetics, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Michael A. Walter
- Department of Medical Genetics, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Alberta, Canada
| |
Collapse
|
17
|
Khalil A, Al-Haddad C, Hariri H, Shibbani K, Bitar F, Kurban M, Nemer G, Arabi M. A Novel Mutation in FOXC1 in a Lebanese Family with Congenital Heart Disease and Anterior Segment Dysgenesis: Potential Roles for NFATC1 and DPT in the Phenotypic Variations. Front Cardiovasc Med 2017; 4:58. [PMID: 28979898 PMCID: PMC5611365 DOI: 10.3389/fcvm.2017.00058] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 08/31/2017] [Indexed: 01/06/2023] Open
Abstract
Congenital heart diseases (CHDs) are still the leading cause of death in neonates. Anterior segment dysgenesis is a broad clinical phenotype that affects the normal development of the eye, leading in most of the cases to glaucoma which is still a major cause of blindness for children and adolescents. Despite tremendous insights gained from genetic studies, a clear genotype–phenotype correlation is still difficult to draw. In Lebanon, a small country with still a high rate of consanguineous marriages, there are little data on the epidemiology of glaucoma amongst children with or without CHD. We carried out whole exome sequencing (WES) on a family with anterior segment dysgenesis, and CHD composed of three affected children with glaucoma, two of them with structural cardiac defects and three healthy siblings. The results unravel a novel mutation in FOXC1 (p. R127H) segregating with the phenotype and inherited from the mother, who did not develop glaucoma. We propose a digenic model for glaucoma in this family by combining the FOXC1 variant with a missense variant inherited from the father in the dermatopontin (DPT) gene. We also unravel a novel NFATC1 missense mutation predicted to be deleterious and present only in the patient with a severe ocular and cardiac phenotype. This is the first report on FOXC1 using WES to genetically characterize a family with both ocular and cardiac malformations. Our results support the usage of such technology to have a better genotype–phenotype picture for Mendelian-inherited diseases for which expressivity and penetrance are still not answered.
Collapse
Affiliation(s)
- Athar Khalil
- Department of Biochemistry and Molecular Genetics, American University of Beirut, Beirut, Lebanon
| | | | - Hadla Hariri
- Department of Biochemistry and Molecular Genetics, American University of Beirut, Beirut, Lebanon
| | - Kamel Shibbani
- Department of Biochemistry and Molecular Genetics, American University of Beirut, Beirut, Lebanon
| | - Fadi Bitar
- Department of Pediatrics and Adolescent Medicine, American University of Beirut, Beirut, Lebanon
| | - Mazen Kurban
- Department of Biochemistry and Molecular Genetics, American University of Beirut, Beirut, Lebanon.,Department of Dermatology, American University of Beirut, Beirut, Lebanon.,Department of Dermatology, Columbia University, New York, NY, United States
| | - Georges Nemer
- Department of Biochemistry and Molecular Genetics, American University of Beirut, Beirut, Lebanon
| | - Mariam Arabi
- Department of Pediatrics and Adolescent Medicine, American University of Beirut, Beirut, Lebanon
| |
Collapse
|
18
|
Lewis CJ, Hedberg-Buenz A, DeLuca AP, Stone EM, Alward WL, Fingert JH. Primary congenital and developmental glaucomas. Hum Mol Genet 2017; 26:R28-R36. [PMID: 28549150 PMCID: PMC5886473 DOI: 10.1093/hmg/ddx205] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 05/24/2017] [Accepted: 05/24/2017] [Indexed: 11/13/2022] Open
Abstract
Glaucoma is the leading cause of irreversible blindness worldwide. Although most glaucoma patients are elderly, congenital glaucoma and glaucomas of childhood are also important causes of visual disability. Primary congenital glaucoma (PCG) is isolated, non-syndromic glaucoma that occurs in the first three years of life and is a major cause of childhood blindness. Other early-onset glaucomas may arise secondary to developmental abnormalities, such as glaucomas that occur with aniridia or as part of Axenfeld-Rieger syndrome. Congenital and childhood glaucomas have strong genetic bases and disease-causing mutations have been discovered in several genes. Mutations in three genes (CYP1B1, LTBP2, TEK) have been reported in PCG patients. Axenfeld-Rieger syndrome is caused by mutations in PITX2 or FOXC1 and aniridia is caused by PAX6 mutations. This review discusses the roles of these genes in primary congenital glaucoma and glaucomas of childhood.
Collapse
Affiliation(s)
- Carly J. Lewis
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
- Stephen A. Wynn Institute for Vision Research, 3111B Medical Education and Research Facility, University of Iowa, Iowa City, IA 52242, USA
| | - Adam Hedberg-Buenz
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
- Stephen A. Wynn Institute for Vision Research, 3111B Medical Education and Research Facility, University of Iowa, Iowa City, IA 52242, USA
| | - Adam P. DeLuca
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
- Stephen A. Wynn Institute for Vision Research, 3111B Medical Education and Research Facility, University of Iowa, Iowa City, IA 52242, USA
| | - Edwin M. Stone
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
- Stephen A. Wynn Institute for Vision Research, 3111B Medical Education and Research Facility, University of Iowa, Iowa City, IA 52242, USA
| | - Wallace L.M. Alward
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
- Stephen A. Wynn Institute for Vision Research, 3111B Medical Education and Research Facility, University of Iowa, Iowa City, IA 52242, USA
| | - John H. Fingert
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
- Stephen A. Wynn Institute for Vision Research, 3111B Medical Education and Research Facility, University of Iowa, Iowa City, IA 52242, USA
| |
Collapse
|
19
|
Sannan NS, Gregory-Evans CY, Lyons CJ, Lehman AM, Langlois S, Warner SJ, Zakrzewski H, Gregory-Evans K. Correlation of novel PAX6 gene abnormalities in aniridia and clinical presentation. Can J Ophthalmol 2017; 52:570-577. [PMID: 29217025 DOI: 10.1016/j.jcjo.2017.04.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 03/24/2017] [Accepted: 04/05/2017] [Indexed: 01/12/2023]
Abstract
OBJECTIVE To describe the clinical presentation and genotype of subjects with aniridia with a particular focus on foveal hypoplasia. DESIGN Prospective cohort study. PARTICIPANTS Thirty-three Canadian participants with aniridia and of various ethnic backgrounds residing in British Columbia. METHODS Full ophthalmic examinations and posterior segment spectral domain-optical coherence tomography (SD-OCT) imaging were performed. Foveal hypoplasia was graded independently by 2 staff ophthalmologists. PAX6 sequencing was performed and chromosomal 11p anomalies investigated. Candidate gene and single-nucleotide polymorphism sequencing in genes functionally related to PAX6 were also studied. RESULTS Best corrected visual acuities in the cohort ranged from 0.0 logMAR to no light perception. Total absence of iris tissue was seen in the majority (42 of 66 eyes). In those in whom SD-OCT was possible, foveal hypoplasia was seen in the majority (45 of 56 eyes, 80%). Molecular genetic defects involving PAX6 were identified in 30 participants (91%), including 4 novel PAX6 mutations (Gly18Val; Ser65ProfsX14; Met337ArgfsX18; Ser321CysfsX34) and 4 novel chromosome 11p deletions inclusive of PAX6 or a known PAX6 regulatory region. CONCLUSIONS The number of PAX6 mutations associated with aniridia continues to increase. Variable foveal architecture despite nearly identical anterior segment disease in 4 participants with an Ex9 ELP4-Ex4 DCDC1 deletion suggested that molecular cues causing variation in disease in the posterior segment differ from those at play in the anterior segment. Results in 3 patients without identifiable PAX6 mutations and a review of the literature suggest that such cases be described as phenocopies rather than actual cases of the syndrome of aniridia.
Collapse
Affiliation(s)
- Naif S Sannan
- Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, B.C
| | - Cheryl Y Gregory-Evans
- Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, B.C
| | - Christopher J Lyons
- Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, B.C; Department of Ophthalmology, BC Children's Hospital, Vancouver, B.C
| | - Anna M Lehman
- Department of Medical Genetics, University of British Columbia, Vancouver, B.C
| | - Sylvie Langlois
- Department of Medical Genetics, University of British Columbia, Vancouver, B.C
| | - Simon J Warner
- Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, B.C
| | - Helen Zakrzewski
- Cumming School of Medicine, University of Calgary, Calgary, Alta
| | - Kevin Gregory-Evans
- Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, B.C.
| |
Collapse
|
20
|
Souzeau E, Siggs OM, Zhou T, Galanopoulos A, Hodson T, Taranath D, Mills RA, Landers J, Pater J, Smith JE, Elder JE, Rait JL, Giles P, Phakey V, Staffieri SE, Kearns LS, Dubowsky A, Mackey DA, Hewitt AW, Ruddle JB, Burdon KP, Craig JE. Glaucoma spectrum and age-related prevalence of individuals with FOXC1 and PITX2 variants. Eur J Hum Genet 2017; 25:839-847. [PMID: 28513611 PMCID: PMC5520071 DOI: 10.1038/ejhg.2017.59] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 02/02/2017] [Accepted: 02/17/2017] [Indexed: 01/26/2023] Open
Abstract
Variation in FOXC1 and PITX2 is associated with Axenfeld-Rieger syndrome, characterised by structural defects of the anterior chamber of the eye and a range of systemic features. Approximately half of all affected individuals will develop glaucoma, but the age at diagnosis and the phenotypic spectrum have not been well defined. As phenotypic heterogeneity is common, we aimed to delineate the age-related penetrance and the full phenotypic spectrum of glaucoma in FOXC1 or PITX2 carriers recruited through a national disease registry. All coding exons of FOXC1 and PITX2 were directly sequenced and multiplex ligation-dependent probe amplification was performed to detect copy number variation. The cohort included 53 individuals from 24 families with disease-associated FOXC1 or PITX2 variants, including one individual diagnosed with primary congenital glaucoma and five with primary open-angle glaucoma. The overall prevalence of glaucoma was 58.5% and was similar for both genes (53.3% for FOXC1 vs 60.9% for PITX2, P=0.59), however, the median age at glaucoma diagnosis was significantly lower in FOXC1 (6.0±13.0 years) compared with PITX2 carriers (18.0±10.6 years, P=0.04). The penetrance at 10 years old was significantly lower in PITX2 than FOXC1 carriers (13.0% vs 42.9%, P=0.03) but became comparable at 25 years old (71.4% vs 57.7%, P=0.38). These findings have important implications for the genetic counselling of families affected by Axenfeld-Rieger syndrome, and also suggest that FOXC1 and PITX2 contribute to the genetic architecture of primary glaucoma subtypes.
Collapse
Affiliation(s)
- Emmanuelle Souzeau
- Department of Ophthalmology, Flinders University, Flinders Medical Centre, Adelaide, SA, Australia
| | - Owen M Siggs
- Department of Ophthalmology, Flinders University, Flinders Medical Centre, Adelaide, SA, Australia
| | - Tiger Zhou
- Department of Ophthalmology, Flinders University, Flinders Medical Centre, Adelaide, SA, Australia
| | - Anna Galanopoulos
- South Australian Institute of Ophthalmology, Royal Adelaide Hospital, Adelaide, SA, Australia
| | - Trevor Hodson
- Mount Gambier Eye Centre, Mount Gambier, SA, Australia
| | - Deepa Taranath
- Department of Ophthalmology, Flinders University, Flinders Medical Centre, Adelaide, SA, Australia
| | - Richard A Mills
- Department of Ophthalmology, Flinders University, Flinders Medical Centre, Adelaide, SA, Australia
| | - John Landers
- Department of Ophthalmology, Flinders University, Flinders Medical Centre, Adelaide, SA, Australia
| | - John Pater
- Department of Ophthalmology, Flinders University, Flinders Medical Centre, Adelaide, SA, Australia
| | - James E Smith
- Department of Ophthalmology, Children’s Hospital at Westmead, Sydney, NSW, Australia
- Discipline of Ophthalmology, University of Sydney, Sydney, NSW, Australia
- Department of Ophthalmology, Macquarie University, Sydney, NSW, Australia
| | - James E Elder
- Department of Ophthalmology, Royal Children’s Hospital, Melbourne, VIC, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, VIC, Australia
| | - Julian L Rait
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, VIC, Australia
- Department of Ophthalmology, University of Melbourne, Melbourne, VIC, Australia
| | - Paul Giles
- Eye Clinic Albury-Wodonga, Albury, NSW, Australia
| | - Vivek Phakey
- Waverley Eye Clinic, Glen Waverley, VIC, Australia
| | - Sandra E Staffieri
- Department of Ophthalmology, Royal Children’s Hospital, Melbourne, VIC, Australia
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, VIC, Australia
- Department of Ophthalmology, University of Melbourne, Melbourne, VIC, Australia
| | - Lisa S Kearns
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, VIC, Australia
- Department of Ophthalmology, University of Melbourne, Melbourne, VIC, Australia
| | - Andrew Dubowsky
- SA Pathology, Flinders Medical Centre, Adelaide, SA, Australia
| | - David A Mackey
- Centre for Ophthalmology and Visual Science, University of Western Australia, Lions Eye Institute, Perth, WA, Australia
- Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS, Australia
| | - Alex W Hewitt
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, VIC, Australia
- Department of Ophthalmology, University of Melbourne, Melbourne, VIC, Australia
- Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS, Australia
| | - Jonathan B Ruddle
- Department of Ophthalmology, Royal Children’s Hospital, Melbourne, VIC, Australia
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, VIC, Australia
- Department of Ophthalmology, University of Melbourne, Melbourne, VIC, Australia
| | - Kathryn P Burdon
- Department of Ophthalmology, Flinders University, Flinders Medical Centre, Adelaide, SA, Australia
- Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS, Australia
| | - Jamie E Craig
- Department of Ophthalmology, Flinders University, Flinders Medical Centre, Adelaide, SA, Australia
| |
Collapse
|
21
|
Seifi M, Footz T, Taylor SAM, Walter MA. Comparison of Bioinformatics Prediction, Molecular Modeling, and Functional Analyses ofFOXC1Mutations in Patients with Axenfeld-Rieger Syndrome. Hum Mutat 2016; 38:169-179. [DOI: 10.1002/humu.23141] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 10/25/2016] [Indexed: 12/13/2022]
Affiliation(s)
- Morteza Seifi
- Department of Medical Genetics; Faculty of Medicine & Dentistry; University of Alberta; Edmonton Alberta Canada
| | - Tim Footz
- Department of Medical Genetics; Faculty of Medicine & Dentistry; University of Alberta; Edmonton Alberta Canada
| | - Sherry A. M. Taylor
- Department of Medical Genetics; Faculty of Medicine & Dentistry; University of Alberta; Edmonton Alberta Canada
| | - Michael A. Walter
- Department of Medical Genetics; Faculty of Medicine & Dentistry; University of Alberta; Edmonton Alberta Canada
| |
Collapse
|
22
|
Seifi M, Footz T, Taylor SAM, Elhady GM, Abdalla EM, Walter MA. Novel PITX2 gene mutations in patients with Axenfeld-Rieger syndrome. Acta Ophthalmol 2016; 94:e571-e579. [PMID: 27009473 DOI: 10.1111/aos.13030] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 01/23/2016] [Indexed: 02/06/2023]
Abstract
PURPOSE Mutations in the bicoid-like transcription factor PITX2 gene often result in Axenfeld-Rieger syndrome (ARS), an autosomal-dominant inherited disorder. We report here the discovery and characterization of novel PITX2 deletions in a small kindred with ARS. METHODS Two familial patients (father and son) from a consanguineous family were examined in the present study. Patient DNA samples were screened for PITX2 mutations by DNA sequencing and for copy number variation by SYBR Green quantitative polymerase chain reaction (PCR) analysis. RESULTS We report a novel deletion involving the coding region of PITX2 in both patients. The minimum size of the deletion is 1 421 914 bp that spans one upstream regulatory element (CE4), PITX2 and a minimum of 13 neighbouring genes. The maximum size of the deletion is 3 789 983 bp. The proband (son) additionally possesses a novel 2-bp deletion in a non-coding exon of the remaining PITX2 allele predicted to alter correct splicing. CONCLUSION Our findings implicate a novel deletion of the PITX2 gene in the pathogenesis of ARS in the affected family. This ARS family presented with an atypical and extremely severe phenotype that resulted in four miscarriages and the death at 10 months of age of a sib of the proband. As the phenotypic manifestations in the proband are more severe than that of the father, we hypothesize that the deletion of the entire PITX2 allele plus a novel 2-bp deletion (observed in the proband) within the remaining PITX2 allele together contributed to the atypical ARS presentation in this family. This is the first study reporting on bi-allelic changes of PITX2 potentially contributing to a more severe ARS phenotype.
Collapse
Affiliation(s)
- Morteza Seifi
- Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Tim Footz
- Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Sherry A M Taylor
- Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Ghada M Elhady
- Department of Human Genetics, Medical Research Institute, Alexandria University, Alexandria, Egypt
| | - Ebtesam M Abdalla
- Department of Human Genetics, Medical Research Institute, Alexandria University, Alexandria, Egypt
| | - Michael A Walter
- Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada.
| |
Collapse
|
23
|
Williams AL, Bohnsack BL. Neural crest derivatives in ocular development: discerning the eye of the storm. ACTA ACUST UNITED AC 2015; 105:87-95. [PMID: 26043871 DOI: 10.1002/bdrc.21095] [Citation(s) in RCA: 93] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 05/12/2015] [Indexed: 01/22/2023]
Abstract
Neural crest cells (NCCs) are vertebrate-specific transient, multipotent, migratory stem cells that play a crucial role in many aspects of embryonic development. These cells emerge from the dorsal neural tube and subsequently migrate to different regions of the body, contributing to the formation of diverse cell lineages and structures, including much of the peripheral nervous system, craniofacial skeleton, smooth muscle, skin pigmentation, and multiple ocular and periocular structures. Indeed, abnormalities in neural crest development cause craniofacial defects and ocular anomalies, such as Axenfeld-Rieger syndrome and primary congenital glaucoma. Thus, understanding the molecular regulation of neural crest development is important to enhance our knowledge of the basis for congenital eye diseases, reflecting the contributions of these progenitors to multiple cell lineages. Particularly, understanding the underpinnings of neural crest formation will help to discern the complexities of eye development, as these NCCs are involved in every aspect of this process. In this review, we summarize the role of ocular NCCs in eye development, particularly focusing on congenital eye diseases associated with anterior segment defects and the interplay between three prominent molecules, PITX2, CYP1B1, and retinoic acid, which act in concert to specify a population of neural crest-derived mesenchymal progenitors for migration and differentiation, to give rise to distinct anterior segment tissues. We also describe recent findings implicating this stem cell population in ocular coloboma formation, and introduce recent evidence suggesting the involvement of NCCs in optic fissure closure and vascular development.
Collapse
Affiliation(s)
- Antionette L Williams
- Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, University of Michigan
| | - Brenda L Bohnsack
- Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, University of Michigan
| |
Collapse
|
24
|
Banerjee S, Hayer K, Hogenesch JB, Granato M. Zebrafish foxc1a drives appendage-specific neural circuit development. Development 2015; 142:753-62. [PMID: 25670796 DOI: 10.1242/dev.115816] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Neural connectivity between the spinal cord and paired appendages is key to the superior locomotion of tetrapods and aquatic vertebrates. In contrast to nerves that innervate axial muscles, those innervating appendages converge at a specialized structure, the plexus, where they topographically reorganize before navigating towards their muscle targets. Despite its importance for providing appendage mobility, the genetic program that drives nerve convergence at the plexus, as well as the functional role of this convergence, are not well understood. Here, we show that in zebrafish the transcription factor foxc1a is dispensable for trunk motor nerve guidance but is required to guide spinal nerves innervating the pectoral fins, equivalent to the tetrapod forelimbs. In foxc1a null mutants, instead of converging with other nerves at the plexus, pectoral fin nerves frequently bypass the plexus. We demonstrate that foxc1a expression in muscle cells delineating the nerve path between the spinal cord and the plexus region restores convergence at the plexus. By labeling individual fin nerves, we show that mutant nerves bypassing the plexus enter the fin at ectopic positions, yet innervate their designated target areas, suggesting that motor axons can select their appropriate fin target area independently of their migration through the plexus. Although foxc1a mutants display topographically correct fin innervation, mutant fin muscles exhibit a reduction in the levels of pre- and postsynaptic structures, concomitant with reduced pectoral fin function. Combined, our results reveal foxc1a as a key player in the development of connectivity between the spinal cord and paired appendages, which is crucial for appendage mobility.
Collapse
Affiliation(s)
- Santanu Banerjee
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Katharina Hayer
- Department of Pharmacology and Institute for Translational Medicine and Therapeutics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - John B Hogenesch
- Department of Pharmacology and Institute for Translational Medicine and Therapeutics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Michael Granato
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| |
Collapse
|
25
|
Du RF, Huang H, Fan LL, Li XP, Xia K, Xiang R. A Novel Mutation of FOXC1 (R127L) in an Axenfeld-Rieger Syndrome Family with Glaucoma and Multiple Congenital Heart Diseases. Ophthalmic Genet 2014; 37:111-5. [PMID: 24914578 DOI: 10.3109/13816810.2014.924016] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Rui-Feng Du
- a Department of Information Management , Hunan University of Finance and Economics , Changsha , China
| | - Hao Huang
- b Department of Cell Biology , School of Life Sciences, Central South University , Changsha , China
| | - Liang-Liang Fan
- b Department of Cell Biology , School of Life Sciences, Central South University , Changsha , China
| | - Xiang-Ping Li
- c Department of Cardiology , the Second Xiangya Hospital of Central South University , Changsha , China , and
| | - Kun Xia
- b Department of Cell Biology , School of Life Sciences, Central South University , Changsha , China .,d State Key Laboratory of Medical Genetics , Central South University , Changsha , China
| | - Rong Xiang
- b Department of Cell Biology , School of Life Sciences, Central South University , Changsha , China .,c Department of Cardiology , the Second Xiangya Hospital of Central South University , Changsha , China , and.,d State Key Laboratory of Medical Genetics , Central South University , Changsha , China
| |
Collapse
|
26
|
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.
Collapse
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
| |
Collapse
|
27
|
Li X, Venugopalan SR, Cao H, Pinho FO, Paine ML, Snead ML, Semina EV, Amendt BA. A model for the molecular underpinnings of tooth defects in Axenfeld-Rieger syndrome. Hum Mol Genet 2014; 23:194-208. [PMID: 23975681 PMCID: PMC3857954 DOI: 10.1093/hmg/ddt411] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Accepted: 08/19/2013] [Indexed: 12/18/2022] Open
Abstract
Patients with Axenfeld-Rieger Syndrome (ARS) present various dental abnormalities, including hypodontia, and enamel hypoplasia. ARS is genetically associated with mutations in the PITX2 gene, which encodes one of the earliest transcription factors to initiate tooth development. Thus, Pitx2 has long been considered as an upstream regulator of the transcriptional hierarchy in early tooth development. However, because Pitx2 is also a major regulator of later stages of tooth development, especially during amelogenesis, it is unclear how mutant forms cause ARS dental anomalies. In this report, we outline the transcriptional mechanism that is defective in ARS. We demonstrate that during normal tooth development Pitx2 activates Amelogenin (Amel) expression, whose product is required for enamel formation, and that this regulation is perturbed by missense PITX2 mutations found in ARS patients. We further show that Pitx2-mediated Amel activation is controlled by chromatin-associated factor Hmgn2, and that Hmgn2 prevents Pitx2 from efficiently binding to and activating the Amel promoter. Consistent with a physiological significance to this interaction, we show that K14-Hmgn2 transgenic mice display a severe loss of Amel expression on the labial side of the lower incisors, as well as enamel hypoplasia-consistent with the human ARS phenotype. Collectively, these findings define transcriptional mechanisms involved in normal tooth development and shed light on the molecular underpinnings of the enamel defect observed in ARS patients who carry PITX2 mutations. Moreover, our findings validate the etiology of the enamel defect in a novel mouse model of ARS.
Collapse
Affiliation(s)
- Xiao Li
- Department of Anatomy and Cell Biology and Craniofacial Anomalies Research Center, The University of Iowa, Iowa City, IA 52244, USA
| | - Shankar R. Venugopalan
- Department of Anatomy and Cell Biology and Craniofacial Anomalies Research Center, The University of Iowa, Iowa City, IA 52244, USA
| | - Huojun Cao
- Department of Anatomy and Cell Biology and Craniofacial Anomalies Research Center, The University of Iowa, Iowa City, IA 52244, USA
| | - Flavia O. Pinho
- Department of Anatomy and Cell Biology and Craniofacial Anomalies Research Center, The University of Iowa, Iowa City, IA 52244, USA
| | - Michael L. Paine
- Center for Craniofacial Molecular Biology, Ostrow School of Dentistry, University of Southern California, Los Angeles, CA, USA and
| | - Malcolm L. Snead
- Center for Craniofacial Molecular Biology, Ostrow School of Dentistry, University of Southern California, Los Angeles, CA, USA and
| | - Elena V. Semina
- Division of Developmental Biology, Department of Pediatrics, The Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Brad A. Amendt
- Department of Anatomy and Cell Biology and Craniofacial Anomalies Research Center, The University of Iowa, Iowa City, IA 52244, USA
| |
Collapse
|
28
|
Yun JW, Cho HK, Oh SY, Ki CS, Kee C. Novel c.300_301delinsT mutation in PITX2 in a Korean family with Axenfeld-Rieger syndrome. Ann Lab Med 2013; 33:360-3. [PMID: 24003428 PMCID: PMC3756242 DOI: 10.3343/alm.2013.33.5.360] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Revised: 05/15/2013] [Accepted: 07/09/2013] [Indexed: 12/05/2022] Open
Abstract
Axenfeld-Rieger syndrome (ARS) is characterized by anomalies of the anterior segment of the eye and systemic abnormalities. Mutations in the FOXC1 and PITX2 genes are underlying causes of ARS, but there has been few reports on genetically confirmed ARS in Korea. We identified a novel PITX2 mutation (c.300_301delinsT) in 2 Korean patients from a family with ARS. We expand the spectrum of PITX2 mutations and, to the best of our knowledge, this is the first confirmed family of PITX2-related ARS in Korea.
Collapse
Affiliation(s)
- Jae Won Yun
- Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Hyun-Kyung Cho
- Department of Ophthalmology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Soo-Young Oh
- Department of Obstetrics and Gynecology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Chang-Seok Ki
- Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Changwon Kee
- Department of Obstetrics and Gynecology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| |
Collapse
|
29
|
Doerdelmann T, Kojetin DJ, Baird-Titus JM, Solt LA, Burris TP, Rance M. Structural and biophysical insights into the ligand-free Pitx2 homeodomain and a ring dermoid of the cornea inducing homeodomain mutant. Biochemistry 2012; 51:665-76. [PMID: 22224469 PMCID: PMC3264736 DOI: 10.1021/bi201639x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The homeodomain-containing transcription factor Pitx2 (pituitary homeobox protein 2) is present in many developing embryonic tissues, including the heart. Its homeodomain is responsible for the recognition and binding to target DNA sequences and thus constitutes a major functional unit in the Pitx2 protein. Nuclear magnetic resonance techniques were employed to determine the solution structure of the native Pitx2 homeodomain and a R24H mutant that causes autosomal dominantly inherited ring dermoid of the cornea syndrome. The structures reveal that both isoforms possess the canonical homeodomain fold. However, the R24H mutation results in a 2-fold increase in DNA binding affinity and a 5 °C decrease in thermal stability, while changing the dynamic environment of the homeodomain only locally. When introduced into full-length Pitx2c, the mutation results in an only 25% loss of transactivation activity. Our data correlate well with clinical observations suggesting a milder deficiency for the R24H mutation compared to those of other Pitx2 homeodomain mutations.
Collapse
Affiliation(s)
- Thomas Doerdelmann
- University of Cincinnati, Department of Molecular Genetics, Biochemistry and Microbiology, 231 Albert Sabin Way, Cincinnati, OH 45267, USA
| | - Douglas J. Kojetin
- University of Cincinnati, Department of Molecular Genetics, Biochemistry and Microbiology, 231 Albert Sabin Way, Cincinnati, OH 45267, USA
- The Scripps Research Institute, Scripps Florida, Department of Molecular Therapeutics, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Jamie M. Baird-Titus
- College of Mount St. Joseph, Department of Chemistry, 5701 Delhi Road, Cincinnati, OH 45233, USA
| | - Laura A. Solt
- The Scripps Research Institute, Scripps Florida, Department of Molecular Therapeutics, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Thomas P. Burris
- The Scripps Research Institute, Scripps Florida, Department of Molecular Therapeutics, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Mark Rance
- University of Cincinnati, Department of Molecular Genetics, Biochemistry and Microbiology, 231 Albert Sabin Way, Cincinnati, OH 45267, USA
| |
Collapse
|
30
|
Castinetti F, Brinkmeier ML, Gordon DF, Vella KR, Kerr JM, Mortensen AH, Hollenberg A, Brue T, Ridgway EC, Camper SA. PITX2 AND PITX1 regulate thyrotroph function and response to hypothyroidism. Mol Endocrinol 2011; 25:1950-60. [PMID: 21964592 PMCID: PMC3386545 DOI: 10.1210/me.2010-0388] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2010] [Accepted: 08/30/2011] [Indexed: 01/05/2023] Open
Abstract
Pitx2 is a homeodomain transcription factor required in a dose-dependent manner for the development of multiple organs. Pitx2-null homozygotes (Pitx2(-/-)) have severe pituitary hypoplasia, whereas mice with reduced-function alleles (Pitx2(neo/neo)) exhibit modest hypoplasia and reduction in the developing gonadotroph and Pou1f1 lineages. PITX2 is expressed broadly in Rathke's pouch and the fetal pituitary gland. It predominates in adult thyrotrophs and gonadotrophs, although it is not necessary for gonadotroph function. To test the role of PITX2 in thyrotroph function, we developed thyrotroph-specific cre transgenic mice, Tg(Tshb-cre) with a recombineered Tshb bacterial artificial chromosome that ablates floxed genes in differentiated pituitary thyrotrophs. We used the best Tg(Tshb-Cre) strain to generate thyrotroph-specific Pitx2-deficient offspring, Pitx2(flox/-;)Tg(Tshb-cre). Double immunohistochemistry confirmed Pitx2 deletion. Pitx2(flox/-);Tg(Tshb-cre) mice have a modest weight decrease. The thyroid glands are smaller, although circulating T(4) and TSH levels are in the normal range. The pituitary levels of Pitx1 transcripts are significantly increased, suggesting a compensatory mechanism. Hypothyroidism induced by low-iodine diet and oral propylthiouracil revealed a blunted TSH response in Pitx2(flox/-);Tg(Tshb-cre) mice. Pitx1 transcripts increased significantly in control mice with induced hypothyroidism, but they remained unchanged in Pitx2(flox/-);Tg(Tshb-cre) mice, possibly because Pitx1 levels were already maximally elevated in untreated mutants. These results suggest that PITX2 and PITX1 have overlapping roles in thyrotroph function and response to hypothyroidism. The novel cre transgene that we report will be useful for studying the function of other genes in thyrotrophs.
Collapse
Affiliation(s)
- F Castinetti
- Department of Human Genetics, University of Michigan, Ann Arbor, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
31
|
Kish PE, Bohnsack BL, Gallina DD, Kasprick DS, Kahana A. The eye as an organizer of craniofacial development. Genesis 2011; 49:222-30. [PMID: 21309065 PMCID: PMC3690320 DOI: 10.1002/dvg.20716] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Revised: 01/03/2011] [Accepted: 01/06/2011] [Indexed: 01/01/2023]
Abstract
The formation and invagination of the optic stalk coincides with the migration of cranial neural crest (CNC) cells, and a growing body of data reveals that the optic stalk and CNC cells communicate to lay the foundations for periocular and craniofacial development. Following migration, the interaction between the developing eye and surrounding periocular mesenchyme (POM) continues, leading to induction of transcriptional regulatory cascades that regulate craniofacial morphogenesis. Studies in chick, mice, and zebrafish have revealed a remarkable level of genetic and mechanistic conservation, affirming the power of each animal model to shed light on the broader morphogenic process. This review will focus on the role of the developing eye in orchestrating craniofacial morphogenesis, utilizing morphogenic gradients, paracrine signaling, and transcriptional regulatory cascades to establish an evolutionarily-conserved facial architecture. We propose that in addition to the forebrain, the eye functions during early craniofacial morphogenesis as a key organizer of facial development, independent of its role in vision.
Collapse
Affiliation(s)
- Phillip E. Kish
- University of Michigan, Ophthalmology and Visual Sciences, Ann Arbor, Michigan, United States,
| | - Brenda L Bohnsack
- University of Michigan, Ophthalmology and Visual Sciences, Ann Arbor, Michigan, United States,
| | - Donika D. Gallina
- University of Michigan, Ophthalmology and Visual Sciences, Ann Arbor, Michigan, United States,
| | - Daniel S. Kasprick
- University of Michigan, Ophthalmology and Visual Sciences, Ann Arbor, Michigan, United States,
| | - Alon Kahana
- University of Michigan, Ophthalmology and Visual Sciences,
| |
Collapse
|
32
|
Kumar S, Duester G. Retinoic acid signaling in perioptic mesenchyme represses Wnt signaling via induction of Pitx2 and Dkk2. Dev Biol 2010; 340:67-74. [PMID: 20122913 PMCID: PMC2834877 DOI: 10.1016/j.ydbio.2010.01.027] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2009] [Revised: 12/20/2009] [Accepted: 01/21/2010] [Indexed: 01/01/2023]
Abstract
Morphogenesis during eye development requires retinoic acid (RA) receptors plus RA-synthesizing enzymes, and loss of RA signaling leads to ocular disorders associated with loss of Pitx2 expression in perioptic mesenchyme. Several Wnt signaling components are expressed in ocular tissues during eye development including Dkk2, encoding an inhibitor of Wnt/beta-catenin signaling, which was previously shown to be induced by Pitx2 in the perioptic mesenchyme. Here, we investigated potential cross-talk between RA and Wnt signaling during ocular development. Genetic studies using Raldh1/Raldh3 double null mice deficient for ocular RA synthesis demonstrated that Pitx2 and Dkk2 were both down-regulated in perioptic mesenchyme. Chromatin immunoprecipitation and gel mobility shift studies demonstrated the existence of a DR5 RA response element upstream of Pitx2 that binds all three RA receptors in embryonic eye. Axin2, an endogenous readout of Wnt/beta-catenin signaling, was up-regulated in cornea and perioptic mesenchyme of RA deficient embryos. Also, expression of Wnt5a was expanded in perioptic mesenchyme of RA deficient eyes. Our findings demonstrate excessive activation of Wnt signaling in the perioptic mesenchyme of RA deficient mice which may be responsible for abnormal development leading to defective optic cup, cornea, and eyelid morphogenesis.
Collapse
Affiliation(s)
- Sandeep Kumar
- Burnham Institute for Medical Research, Development and Aging Program, 10901 North Torrey Pines Road, La Jolla, California 92037, USA
| | - Gregg Duester
- Burnham Institute for Medical Research, Development and Aging Program, 10901 North Torrey Pines Road, La Jolla, California 92037, USA
| |
Collapse
|
33
|
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.
Collapse
|
34
|
Fetterman CD, Mirzayans F, Walter MA. Characterization of a novel FOXC1 mutation, P297S, identified in two individuals with anterior segment dysgenesis. Clin Genet 2010; 76:296-9. [PMID: 19793056 DOI: 10.1111/j.1399-0004.2009.01210.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
35
|
Simard A, Di Giorgio L, Amen M, Westwood A, Amendt BA, Ryan AK. The Pitx2c N-terminal domain is a critical interaction domain required for asymmetric morphogenesis. Dev Dyn 2009; 238:2459-70. [PMID: 19681163 PMCID: PMC3014603 DOI: 10.1002/dvdy.22062] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The paired-like homeodomain transcription factor Pitx2c has an essential role in patterning the left-right axis. However, neither its transcriptional targets nor the molecular mechanisms through which it exerts its patterning function are known. Here we provide evidence that the N-terminal domain of Pitx2c is important for this activity. Overexpression of the Pitx2c N-terminus in ovo randomizes the direction of heart looping, the first morphological asymmetry conserved in vertebrate embryos. In addition, the Pitx2c N-terminal domain blocks the ability of Pitx2c to synergize with Nkx2.5 to transactivate the procollagen lysyl hydroxylase (Plod-1) promoter in transient transfection assays. A five amino acid region containing leucine-41 is required for both of these effects. Our data suggest that the Pitx2c N-terminal domain competes with endogenous Pitx2c for binding to a protein interaction partner that is required for the activation of genes that direct asymmetric morphogenesis along the left-right axis.
Collapse
Affiliation(s)
- Annie Simard
- The Research Institute of the McGill University Health Center, Montreal, Quebec
| | | | - Melanie Amen
- Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, TX
| | - Ashley Westwood
- Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, TX
| | - Brad A. Amendt
- Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, TX
| | - Aimee K. Ryan
- The Research Institute of the McGill University Health Center, Montreal, Quebec
- Department of Human Genetics, McGill University, Montreal, Quebec
- Department of Pediatrics, McGill University, Montreal, Quebec
| |
Collapse
|
36
|
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.
Collapse
Affiliation(s)
- P Meyer-Marcotty
- Department of Orthodontics, Dental Clinic of the Medical Faculty, University of Wuerzburg, Wuerzburg, Germany.
| | | | | | | | | |
Collapse
|
37
|
Abstract
PURPOSE OF REVIEW Primary angle closure typically causes acute intraocular pressure rise in the phakic elderly. Alternative diagnoses, however, for which iridotomy is usually ineffective, occur commonly in younger, nonhyperopic, and pseudophakic patients. RECENT FINDINGS High-resolution ultrasonography has advanced our understanding of these entities. Management of platueau iris, present in over half of angle closures with patent iridotomy, may depend on disease stage. Early postoperative pseudophakic patients with myopic shift and narrow angle should be treated with laser capsulotomy for capsular block. Bilateral angle closure is usually due to an offending systemic pharmacologic agent, which must be stopped to resolve the closure. Ciliary body swelling often produces angle closure by blocking the access of aqueous to the anterior chamber, sometimes paradoxically after hypotony. Annular choroidal effusions, difficult to detect without ultrasound, may mimic angle closure. Although cycloplegic and corticosteroid therapy may resolve some entities, pars plana vitrectomy and lensectomy may be necessary to resolve severe ciliary block. We also discuss unique variants of angle closure in patients with retinal disease. SUMMARY Atypical angle closures should always be considered. Careful examination techniques and new technology can detect the mechanisms involved and direct treatment.
Collapse
|
38
|
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.
Collapse
Affiliation(s)
- E Engenheiro
- Department of Cellular and Molecular Medicine, Wilhelm Johannsen Center for Functional Genome Research, University of Copenhagen, Copenhagen, Denmark.
| | | | | | | | | | | | | | | |
Collapse
|