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Li J, Wang C, Zhang S, Cai B, Pan B, Sun C, Qi X, Ma C, Fang W, Jin K, Bi X, Jin Z, Zhuang W. Genetic detection of two novel LRP5 pathogenic variants in patients with familial exudative vitreoretinopathy. BMC Ophthalmol 2023; 23:489. [PMID: 38030997 PMCID: PMC10685552 DOI: 10.1186/s12886-023-03243-2] [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: 12/31/2022] [Accepted: 11/23/2023] [Indexed: 12/01/2023] Open
Abstract
BACKGROUND Familial exudative vitreoretinopathy (FEVR) is a genetic eye disorder that leads to abnormal development of retinal blood vessels, resulting in vision impairment. This study aims to identify pathogenic variants by targeted exome sequencing in 9 independent pedigrees with FEVR and characterize the novel pathogenic variants by molecular dynamics simulation. METHODS Clinical data were collected from 9 families with FEVR. The causative genes were screened by targeted next-generation sequencing (TGS) and verified by Sanger sequencing. In silico analyses (SIFT, Polyphen2, Revel, MutationTaster, and GERP + +) were carried out to evaluate the pathogenicity of the variants. Molecular dynamics was simulated to predict protein conformation and flexibility transformation alterations on pathogenesis. Furthermore, molecular docking techniques were employed to explore the interactions and binding properties between LRP5 and DKK1 proteins relevant to the disease. RESULTS A 44% overall detection rate was achieved with four variants including c.4289delC: p.Pro1431Argfs*8, c.2073G > T: p.Trp691Cys, c.1801G > A: p.Gly601Arg in LRP5 and c.633 T > A: p.Tyr211* in TSPAN12 in 4 unrelated probands. Based on in silico analysis and ACMG standard, two of them, c.4289delC: p.Pro1431Argfs*8 and c.2073G > T: p.Trp691Cys of LRP5 were identified as novel pathogenic variants. Based on computational predictions using molecular dynamics simulations and molecular docking, there are indications that these two variants might lead to alterations in the secondary structure and spatial conformation of the protein, potentially impacting its rigidity and flexibility. Furthermore, these pathogenic variants are speculated to potentially influence hydrogen bonding interactions and could result in an increased binding affinity with the DKK1 protein. CONCLUSIONS Two novel genetic variants of the LRP5 gene were identified, expanding the range of mutations associated with FEVR. Through molecular dynamics simulations and molecular docking, the potential impact of these variants on protein structure and their interactions with the DKK1 protein has been explored. These findings provide further support for the involvement of these variants in the pathogenesis of the disease.
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Affiliation(s)
- Jiayu Li
- Third Clinical Medical College of Ningxia Medical University, Shengli Street, Yinchuan, 750004, Ningxia, China
- Ningxia Eye Hospital, People's Hospital of Ningxia Hui Autonomous Region, Huanghe Road, Yinchuan, 750011, Ningxia, China
| | - Chanjuan Wang
- Ningxia Eye Hospital, People's Hospital of Ningxia Hui Autonomous Region, Huanghe Road, Yinchuan, 750011, Ningxia, China
| | - Shaochi Zhang
- Ningxia Eye Hospital, People's Hospital of Ningxia Hui Autonomous Region, Huanghe Road, Yinchuan, 750011, Ningxia, China
| | - Bo Cai
- Ningxia Eye Hospital, People's Hospital of Ningxia Hui Autonomous Region, Huanghe Road, Yinchuan, 750011, Ningxia, China
| | - Bo Pan
- Ningxia Eye Hospital, People's Hospital of Ningxia Hui Autonomous Region, Huanghe Road, Yinchuan, 750011, Ningxia, China
| | - Caihong Sun
- Third Clinical Medical College of Ningxia Medical University, Shengli Street, Yinchuan, 750004, Ningxia, China
- Ningxia Eye Hospital, People's Hospital of Ningxia Hui Autonomous Region, Huanghe Road, Yinchuan, 750011, Ningxia, China
| | - Xiaolong Qi
- Ningxia Eye Hospital, People's Hospital of Ningxia Hui Autonomous Region, Huanghe Road, Yinchuan, 750011, Ningxia, China
| | - Chunmei Ma
- Ningxia Eye Hospital, People's Hospital of Ningxia Hui Autonomous Region, Huanghe Road, Yinchuan, 750011, Ningxia, China
| | - Wei Fang
- Ningxia Eye Hospital, People's Hospital of Ningxia Hui Autonomous Region, Huanghe Road, Yinchuan, 750011, Ningxia, China
| | - Kangxin Jin
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, 100005, China
| | - Xiaojun Bi
- Ningxia Eye Hospital, People's Hospital of Ningxia Hui Autonomous Region, Huanghe Road, Yinchuan, 750011, Ningxia, China.
| | - Zibing Jin
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, 100005, China.
| | - Wenjuan Zhuang
- Third Clinical Medical College of Ningxia Medical University, Shengli Street, Yinchuan, 750004, Ningxia, China.
- Ningxia Eye Hospital, People's Hospital of Ningxia Hui Autonomous Region, Huanghe Road, Yinchuan, 750011, Ningxia, China.
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Zhao R, Wang S, Zhao P, Dai E, Zhang X, Peng L, He Y, Yang M, Li S, Yang Z. Heterozygote loss-of-function variants in the LRP5 gene cause familial exudative vitreoretinopathy. Clin Exp Ophthalmol 2022; 50:441-448. [PMID: 35133048 DOI: 10.1111/ceo.14037] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 11/22/2021] [Accepted: 12/10/2021] [Indexed: 12/12/2022]
Abstract
BACKGROUND Familial exudative vitreoretinopathy (FEVR) is an inherited ocular disease with clinical manifestations of aberrant retinal vasculature. We aimed to identify novel causative variants responsible for FEVR and provided evidence for the genetic counselling of FEVR. METHODS We applied whole-exome sequencing (WES) on the genomic DNA samples from the probands and performed Sanger sequencing for variant validation. Western blot analysis and luciferase assays were performed to test the expression levels and the activity of mutant proteins. RESULTS We identified one novel heterozygous nonsense variant, and three novel heterozygous frameshift variants including c.1801G>T (p.G601*), c.1965delC (p.H656Tfs*41), c.4445delC (p.S1482Cfs*17), and c.4482delC (p.P1495Rfs*4), which disabled the function of LRP5 on the Norrin/β-catenin signalling. Overexpression of variant-carrying LRP5 proteins resulted in down regulation of the protein levels of β-catenin and the Norrin/β-catenin signalling target genes c-Myc and Glut1. CONCLUSION Our study showed that four inherited LRP5 variants can cause autosomal dominant FEVR via down regulation of Norrin/β-catenin signalling and expanded the spectrum of FEVR-associated LRP5 variants.
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Affiliation(s)
- Rulian Zhao
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan, China.,Research Unit for Blindness Prevention of Chinese Academy of Medical Sciences (2019RU026), Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, Chengdu, Sichuan, China
| | - Shiyuan Wang
- Ophthalmology, Shanghai Jiaotong University School of Medicine Xinhua Hospital, Shanghai, China
| | - Peiquan Zhao
- Ophthalmology, Shanghai Jiaotong University School of Medicine Xinhua Hospital, Shanghai, China
| | - Erkuan Dai
- Ophthalmology, Shanghai Jiaotong University School of Medicine Xinhua Hospital, Shanghai, China
| | - Xiang Zhang
- Ophthalmology, Shanghai Jiaotong University School of Medicine Xinhua Hospital, Shanghai, China
| | - Li Peng
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan, China.,Research Unit for Blindness Prevention of Chinese Academy of Medical Sciences (2019RU026), Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, Chengdu, Sichuan, China.,Natural Products Research Center, Institute of Chengdu Biology, Sichuan Translational Medicine Hospital, Chinese Academy of Sciences, Chengdu, Sichuan, China
| | - Yunqi He
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan, China.,Research Unit for Blindness Prevention of Chinese Academy of Medical Sciences (2019RU026), Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, Chengdu, Sichuan, China.,Natural Products Research Center, Institute of Chengdu Biology, Sichuan Translational Medicine Hospital, Chinese Academy of Sciences, Chengdu, Sichuan, China
| | - Mu Yang
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan, China.,Research Unit for Blindness Prevention of Chinese Academy of Medical Sciences (2019RU026), Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, Chengdu, Sichuan, China.,Natural Products Research Center, Institute of Chengdu Biology, Sichuan Translational Medicine Hospital, Chinese Academy of Sciences, Chengdu, Sichuan, China
| | - Shujin Li
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan, China.,Research Unit for Blindness Prevention of Chinese Academy of Medical Sciences (2019RU026), Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, Chengdu, Sichuan, China.,Natural Products Research Center, Institute of Chengdu Biology, Sichuan Translational Medicine Hospital, Chinese Academy of Sciences, Chengdu, Sichuan, China
| | - Zhenglin Yang
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan, China.,Research Unit for Blindness Prevention of Chinese Academy of Medical Sciences (2019RU026), Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, Chengdu, Sichuan, China.,Natural Products Research Center, Institute of Chengdu Biology, Sichuan Translational Medicine Hospital, Chinese Academy of Sciences, Chengdu, Sichuan, China
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3
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Familial Exudative Vitreoretinopathy: An Update on Genetics and Imaging. Clin Ophthalmol 2020; 60:169-177. [DOI: 10.1097/iio.0000000000000336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Variable reduction in Norrin signaling activity caused by novel mutations in FZD4 identified in patients with familial exudative vitreoretinopathy. Mol Vis 2019; 25:60-69. [PMID: 30820142 PMCID: PMC6377376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 02/05/2019] [Indexed: 11/04/2022] Open
Abstract
Purpose To identify novel mutations in FZD4 and to investigate their pathogenicity in a cohort of Chinese patients with familial exudative vitreoretinopathy (FEVR). Methods Next-generation sequencing was performed in patients with a clinical diagnosis of FEVR. Wide-field angiography was performed in probands and family members if available. Clinical data were collected from patient charts. The effect of the mutations in FZD4 on its biologic activity in the Norrin/β-catenin signaling pathway was analyzed with the luciferase reporter assay. Results Four novel mutations in FZD4 (c.1188_1192del/p.F396fs, c.1220delC/p.A407Vfs*24, c.905G>A/p.C302Y, c.1325T>A/p.V442E) were identified in four unrelated families. The mutations were not detected in 200 healthy individuals. The variability of the ocular phenotypes was not only observed in the probands and parents harboring the same mutation but also between two eyes in one individual. All four novel mutations introduced reduction in luciferase activity. Compared with the wild-type, the FZD4 level of the four mutants also decreased variably. Conclusions Four novel mutations in FZD4 were identified in Chinese patients with FEVR. No correlation in the reduced luciferase activity and the ocular phenotype was observed in this study. This study further emphasized the complexity of the FEVR-causing machinery.
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Pharmacologic Activation of Wnt Signaling by Lithium Normalizes Retinal Vasculature in a Murine Model of Familial Exudative Vitreoretinopathy. THE AMERICAN JOURNAL OF PATHOLOGY 2016; 186:2588-600. [PMID: 27524797 DOI: 10.1016/j.ajpath.2016.06.015] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Revised: 06/16/2016] [Accepted: 06/21/2016] [Indexed: 12/12/2022]
Abstract
Familial exudative vitreoretinopathy (FEVR) is characterized by delayed retinal vascular development, which promotes hypoxia-induced pathologic vessels. In severe cases FEVR may lead to retinal detachment and visual impairment. Genetic studies linked FEVR with mutations in Wnt signaling ligand or receptors, including low-density lipoprotein receptor-related protein 5 (LRP5) gene. Here, we investigated ocular pathologies in a Lrp5 knockout (Lrp5(-/-)) mouse model of FEVR and explored whether treatment with a pharmacologic Wnt activator lithium could bypass the genetic defects, thereby protecting against eye pathologies. Lrp5(-/-) mice displayed significantly delayed retinal vascular development, absence of deep layer retinal vessels, leading to increased levels of vascular endothelial growth factor and subsequent pathologic glomeruloid vessels, as well as decreased inner retinal visual function. Lithium treatment in Lrp5(-/-) mice significantly restored the delayed development of retinal vasculature and the intralaminar capillary networks, suppressed formation of pathologic glomeruloid structures, and promoted hyaloid vessel regression. Moreover, lithium treatment partially rescued inner-retinal visual function and increased retinal thickness. These protective effects of lithium were largely mediated through restoration of canonical Wnt signaling in Lrp5(-/-) retina. Lithium treatment also substantially increased vascular tubular formation in LRP5-deficient endothelial cells. These findings suggest that pharmacologic activation of Wnt signaling may help treat ocular pathologies in FEVR and potentially other defective Wnt signaling-related diseases.
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Musada GR, Jalali S, Hussain A, Chururu AR, Gaddam PR, Chakrabarti S, Kaur I. Mutation spectrum of the Norrie disease pseudoglioma (NDP) gene in Indian patients with FEVR. Mol Vis 2016; 22:491-502. [PMID: 27217716 PMCID: PMC4872281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 05/13/2016] [Indexed: 11/25/2022] Open
Abstract
PURPOSE Mutations in the Norrie disease pseudoglioma (NDP; Xp11.3) gene have been involved in retinal blood vessel formation and neural differentiation and are implicated in familial exudative vitreoretinopathy (FEVR) cases. However, the role of the gene has not been explored in the Indian context. Thus, this study was designed to understand the involvement of NDP among Indian patients with FEVR. METHODS The study cohort comprised 225 subjects, including unrelated patients with FEVR (n = 110) and ethnically matched healthy subjects (n = 115) recruited from a tertiary eye care center in India. The entire coding regions, intron-exon boundaries, along with the 5' and 3' untranslated regions of NDP were screened with resequencing following standard protocols. The spectrum of the observed variants was analyzed in conjunction with data available from other populations. RESULTS Eight potentially pathogenic mutations (p.His4ArgfsX21, p.Asp23GlufsX9, p.Ile48ValfsX55, p.His50Asp, p.Ser57*, p.Gly113Asp, p.Arg121Gln, and p.Cys126Arg, including five novel ones), were observed in the coding region of the NDP gene in ten unrelated FEVR probands (9%). The novel changes were not observed in the control subjects and were unavailable in the dbSNP, ESP5400, NIEHS95, and ExAC databases. All probands with NDP mutations exhibited classical features of the disease as observed among patients with FEVR worldwide. CONCLUSIONS This is perhaps the first study to demonstrate the involvement of NDP among patients with Indian FEVR that further expands its mutation spectrum. The data generated could have broad implications in genetic counseling, disease management, and early intervention for a better prognosis in FEVR.
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Affiliation(s)
- Ganeswara Rao Musada
- Kallam Anji Reddy Molecular Genetics Laboratory, Brien Holden Eye Research Centre, BHERC, L V Prasad Eye Institute, Hyderabad, India
| | - Subhadra Jalali
- Smt. Kanuri Santhamma Centre for Vitreo Retinal Diseases, L V Prasad Eye Institute, Hyderabad, India
| | - Anjli Hussain
- Smt. Kanuri Santhamma Centre for Vitreo Retinal Diseases, L V Prasad Eye Institute, Hyderabad, India
| | | | | | - Subhabrata Chakrabarti
- Kallam Anji Reddy Molecular Genetics Laboratory, Brien Holden Eye Research Centre, BHERC, L V Prasad Eye Institute, Hyderabad, India
| | - Inderjeet Kaur
- Kallam Anji Reddy Molecular Genetics Laboratory, Brien Holden Eye Research Centre, BHERC, L V Prasad Eye Institute, Hyderabad, India
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Welinder LG, Robitaille JM, Rupps R, Boerkoel CF, Lyons CJ. Congenital Bilateral Retinal Detachment in Two Siblings with Osteoporosis-Pseudoglioma Syndrome. Ophthalmic Genet 2015; 36:276-80. [DOI: 10.3109/13816810.2015.1016240] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Xu Y, Huang L, Li J, Zhang Q, Fei P, Zhu X, Tai Z, Ma S, Gong B, Li Y, Zang W, Zhu X, Zhao P, Yang Z. Novel mutations in the TSPAN12 gene in Chinese patients with familial exudative vitreoretinopathy. Mol Vis 2014; 20:1296-306. [PMID: 25352738 PMCID: PMC4169774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2014] [Accepted: 09/18/2014] [Indexed: 11/30/2022] Open
Abstract
PURPOSE Familial exudative vitreoretinopathy (FEVR) is a group of inherited blinding eye diseases characterized by defects in the development of the retinal vessels. Recent studies have identified genetic variants in tetraspanin 12 (TSPAN12) as a cause of FEVR. The purpose of this study was to identify novel TSPAN12 mutations in Chinese patients with FEVR and to describe the associated phenotypes. METHODS Mutation screening was performed by directly sequencing PCR products of genomic DNA with primers designed to amplify the seven coding exons and adjacent intronic regions of the FEVR-causing gene TSPAN12. Clinical phenotypes of the patients with TSPAN12 mutations were documented. Wild-type and mutant TSPAN12 proteins were assayed for the Norrin-β-catenin signaling pathway with luciferase reporter assays. RESULTS Three novel heterozygous mutations in TSPAN12 were identified: c.566G>A (p.C189Y), c.177delC (p.Y59fsX67), and c.C254T (p.T85M). All three mutations involved highly conserved residues and were not present in 200 normal individuals. Ocular phenotypes included increased ramification of the peripheral retinal vessels, a peripheral avascular zone, inferotemporal dragging of the optic disc and macula, and retinal folds. The probands showed relatively severe retinopathy, whereas the other family members were often asymptomatic. In SuperTopFlash (STF) cell line transfection studies, C189Y, Y59fsX67, and T85M mutants failed to induce luciferase reporter activity in response to Norrin. CONCLUSIONS We found three novel TSPAN12 mutations in Chinese patients with autosomal dominant FEVR, and suggest that TSPAN12 mutations cause FEVR. The phenotypes associated with the TSPAN12 mutations showed extensive variation in disease severity among members of the same family, which implied the complexity of FEVR mutations and phenotypes.
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Affiliation(s)
- Yu Xu
- Department of Ophthalmology, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Lulin Huang
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, University of electronic science and technology affiliated hospital & Sichuan Provincial People’s Hospital, Sichuan, China,School of Medicine, University of Electronic Science and Technology, Sichuan, China,Chengdu Institute of Biology, Chinese Academy of Sciences and Chinese Academy of Sciences Sichuan Translational Medicine Research Hospital, Chengdu, Sichuan, China
| | - Jing Li
- Department of Ophthalmology, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Qi Zhang
- Department of Ophthalmology, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Ping Fei
- Department of Ophthalmology, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiong Zhu
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, University of electronic science and technology affiliated hospital & Sichuan Provincial People’s Hospital, Sichuan, China,School of Medicine, University of Electronic Science and Technology, Sichuan, China,Chengdu Institute of Biology, Chinese Academy of Sciences and Chinese Academy of Sciences Sichuan Translational Medicine Research Hospital, Chengdu, Sichuan, China
| | - Zhengfu Tai
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, University of electronic science and technology affiliated hospital & Sichuan Provincial People’s Hospital, Sichuan, China,Chengdu Institute of Biology, Chinese Academy of Sciences and Chinese Academy of Sciences Sichuan Translational Medicine Research Hospital, Chengdu, Sichuan, China
| | - Shi Ma
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, University of electronic science and technology affiliated hospital & Sichuan Provincial People’s Hospital, Sichuan, China,School of Medicine, University of Electronic Science and Technology, Sichuan, China
| | - Bo Gong
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, University of electronic science and technology affiliated hospital & Sichuan Provincial People’s Hospital, Sichuan, China,School of Medicine, University of Electronic Science and Technology, Sichuan, China
| | - Yun Li
- Medicine Program, Geisel School of Medicine, Dartmouth College, Hanover, NH
| | - Weizhou Zang
- Department of Neurology, Henan Provincial People’s Hospital, Zhengzhou, Henan, China
| | - Xianjun Zhu
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, University of electronic science and technology affiliated hospital & Sichuan Provincial People’s Hospital, Sichuan, China,School of Medicine, University of Electronic Science and Technology, Sichuan, China,Chengdu Institute of Biology, Chinese Academy of Sciences and Chinese Academy of Sciences Sichuan Translational Medicine Research Hospital, Chengdu, Sichuan, China
| | - Peiquan Zhao
- Department of Ophthalmology, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Zhenglin Yang
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, University of electronic science and technology affiliated hospital & Sichuan Provincial People’s Hospital, Sichuan, China,School of Medicine, University of Electronic Science and Technology, Sichuan, China,Chengdu Institute of Biology, Chinese Academy of Sciences and Chinese Academy of Sciences Sichuan Translational Medicine Research Hospital, Chengdu, Sichuan, China
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Stagi S, Cavalli L, Seminara S, de Martino M, Brandi ML. The ever-expanding conundrum of primary osteoporosis: aetiopathogenesis, diagnosis, and treatment. Ital J Pediatr 2014; 40:55. [PMID: 24906390 PMCID: PMC4064514 DOI: 10.1186/1824-7288-40-55] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Accepted: 05/27/2014] [Indexed: 01/07/2023] Open
Abstract
In recent years, as knowledge regarding the etiopathogenetic mechanisms of bone involvement characterizing many diseases has increased and diagnostic techniques evaluating bone health have progressively improved, the problem of low bone mass/quality in children and adolescents has attracted more and more attention, and the body evidence that there are groups of children who may be at risk of osteoporosis has grown. This interest is linked to an increased understanding that a higher peak bone mass (PBM) may be one of the most important determinants affecting the age of onset of osteoporosis in adulthood. This review provides an updated picture of bone pathophysiology and characteristics in children and adolescents with paediatric osteoporosis, taking into account the major causes of primary osteoporosis (PO) and evaluating the major aspects of bone densitometry in these patients. Finally, some options for the treatment of PO will be briefly discussed.
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Affiliation(s)
- Stefano Stagi
- Health Sciences Department, University of Florence, Anna Meyer Children's University Hospital, Florence, Italy.
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Campos-Obando N, Oei L, Hoefsloot LH, Kiewiet RM, Klaver CCW, Simon MEH, Zillikens MC. Osteoporotic vertebral fractures during pregnancy: be aware of a potential underlying genetic cause. J Clin Endocrinol Metab 2014; 99:1107-11. [PMID: 24423337 DOI: 10.1210/jc.2013-3238] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
CONTEXT Although the baby growing in its mother's womb needs calcium for skeletal development, osteoporosis and fractures very rarely occur during pregnancy. CASE PRESENTATION A 27-year-old woman in the seventh month of her first pregnancy contracted midthoracic back pain after lifting an object. The pain was attributed to her pregnancy, but it remained postpartum. Her past medical history was uneventful, except for severely reduced vision of her left eye since birth. Family history revealed that her maternal grandmother had postmenopausal osteoporosis and her half-brother had three fractures during childhood after minor trauma. Her height was 1.58 m; she had no blue sclerae or joint hyperlaxity. Laboratory examination including serum calcium, phosphate, alkaline phosphatase, creatinine, β-carboxyterminal cross-linking telopeptide of type I collagen, 25-hydroxyvitamin D, and TSH was normal. Multiple thoracic vertebral fractures were diagnosed on x-ray examination, and dual-energy x-ray absorptiometry scanning showed severe osteoporosis (Z-scores: L2-L4, -5.6 SD; femur neck, -3.9 SD). DNA analyses revealed two compound heterozygous missense mutations in LRP5. The patient's mother carried one of the LRP5 mutations and was diagnosed with osteoporosis. Her half-brother, treated with cabergoline for a microprolactinoma, also had osteoporosis of the lumbar spine on dual-energy x-ray absorptiometry and carried the same LRP5 mutation. The patient was treated with risedronate for 2.5 years. Bone mineral density and back pain improved. She stopped bisphosphonate use 6 months before planning a second pregnancy. CONCLUSION Our patient was diagnosed with osteoporosis pseudoglioma syndrome/familial exudative vitreoretinopathy. Potential underlying genetic causes should be considered in pregnancy-associated osteoporosis with implications for patients and relatives. More studies regarding osteoporosis treatment preceding conception are desirable.
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Affiliation(s)
- Natalia Campos-Obando
- Department of Internal Medicine (N.C.-O., L.O., M.C.Z.), Erasmus MC, 3015 CE Rotterdam, The Netherlands; Department of Human Genetics (L.H.H.), Radboud Medical Center, 6500 HC Nijmegen, The Netherlands; Department of Internal Medicine (R.M.K.), Albert Schweitzer Hospital, 3318 AT Dordrecht, The Netherlands; and Departments of Ophthalmology (C.C.W.K.) and Clinical Genetics (M.E.H.S.), Erasmus MC, 3015 CE Rotterdam, The Netherlands
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Fei P, Zhang Q, Huang L, Xu Y, Zhu X, Tai Z, Gong B, Ma S, Yao Q, Li J, Zhao P, Yang Z. Identification of two novel LRP5 mutations in families with familial exudative vitreoretinopathy. Mol Vis 2014; 20:395-409. [PMID: 24715757 PMCID: PMC3976684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Accepted: 03/27/2014] [Indexed: 11/16/2022] Open
Abstract
PURPOSE To investigate the clinical features and disease-causing mutations in two Chinese families with familial exudative vitreoretinopathy (FEVR). METHODS Clinical data and genomic DNA were collected for patients with FEVR. The coding exons and adjacent intronic regions of FZD4, LRP5, TSPAN12, and NDP were amplified with PCR, and the resulting amplicons were analyzed with Sanger sequencing. Wild-type and mutant LRP5 proteins were assayed for the Norrin/β-catenin pathway by luciferase reporter assays. RESULTS Two novel heterozygous mutations in the LRP5 gene were identified in two relatives--p.A422T and p.L540P. Typical FEVR fundus change and mild reduced bone mineral density (BMD) was found in the two patients and the affected parent. In the luciferase studies, both p.A422T and p.L540P mutants displayed a significant reduction of the luciferase activity in SuperTopFlash (STF) cells in response to Norrin (87% reduction for p.A422T and 97% reduction for p.L540P). Both patients had an additional LRP5 sequence change (p.Q816P in Patient 1 from the unaffected mother and p.T852M in Patient 2 verified as a new mutation). Luciferase assay showed no reduction for p.Q816P and 94.9% reduction for the new mutation p.T852M, suggesting that p.Q816P may be not pathogenic and p.T852M may be pathogenic. CONCLUSIONS Our findings demonstrated two new novel LRP5 mutations in Chinese patients with FEVR and mild reduced BMD. They emphasize the complexity of FEVR mutations and phenotypes.
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Affiliation(s)
- Ping Fei
- Department of Ophthalmology, Xin Hua Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Qi Zhang
- Department of Ophthalmology, Xin Hua Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Luling Huang
- Sichuan Key Laboratory for Human Disease Gene Study, Institute of Laboratory Medicine, School of Medicine, University of Science and Technology of China & Sichuan Provincial People's Hospital & Sichuan Provincial People’s Hospital, Sichuan, China
| | - Yu Xu
- Department of Ophthalmology, Xin Hua Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiong Zhu
- Sichuan Key Laboratory for Human Disease Gene Study, Institute of Laboratory Medicine, School of Medicine, University of Science and Technology of China & Sichuan Provincial People's Hospital & Sichuan Provincial People’s Hospital, Sichuan, China
| | - Zhengfu Tai
- Sichuan Key Laboratory for Human Disease Gene Study, Institute of Laboratory Medicine, School of Medicine, University of Science and Technology of China & Sichuan Provincial People's Hospital & Sichuan Provincial People’s Hospital, Sichuan, China
| | - Bo Gong
- Sichuan Key Laboratory for Human Disease Gene Study, Institute of Laboratory Medicine, School of Medicine, University of Science and Technology of China & Sichuan Provincial People's Hospital & Sichuan Provincial People’s Hospital, Sichuan, China
| | - Shi Ma
- Sichuan Key Laboratory for Human Disease Gene Study, Institute of Laboratory Medicine, School of Medicine, University of Science and Technology of China & Sichuan Provincial People's Hospital & Sichuan Provincial People’s Hospital, Sichuan, China
| | | | - Jing Li
- Department of Ophthalmology, Xin Hua Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Peiquan Zhao
- Department of Ophthalmology, Xin Hua Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Zhenglin Yang
- Sichuan Key Laboratory for Human Disease Gene Study, Institute of Laboratory Medicine, School of Medicine, University of Science and Technology of China & Sichuan Provincial People's Hospital & Sichuan Provincial People’s Hospital, Sichuan, China
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Kwinta P, Pietrzyk JJ. Retinopathy of prematurity: is genetic predisposition an important risk factor? EXPERT REVIEW OF OPHTHALMOLOGY 2014. [DOI: 10.1586/17469899.2.2.275] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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13
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Shastry BS. Genetics of familial exudative vitreoretinopathy and its implications for management. EXPERT REVIEW OF OPHTHALMOLOGY 2014. [DOI: 10.1586/eop.12.40] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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14
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Khan K, Logan CV, McKibbin M, Sheridan E, Elçioglu NH, Yenice O, Parry DA, Fernandez-Fuentes N, Abdelhamed ZIA, Al-Maskari A, Poulter JA, Mohamed MD, Carr IM, Morgan JE, Jafri H, Raashid Y, Taylor GR, Johnson CA, Inglehearn CF, Toomes C, Ali M. Next generation sequencing identifies mutations in Atonal homolog 7 (ATOH7) in families with global eye developmental defects. Hum Mol Genet 2011; 21:776-83. [PMID: 22068589 PMCID: PMC3263993 DOI: 10.1093/hmg/ddr509] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The atonal homolog 7 (ATOH7) gene encodes a transcription factor involved in determining the fate of retinal progenitor cells and is particularly required for optic nerve and ganglion cell development. Using a combination of autozygosity mapping and next generation sequencing, we have identified homozygous mutations in this gene, p.E49V and p.P18RfsX69, in two consanguineous families diagnosed with multiple ocular developmental defects, including severe vitreoretinal dysplasia, optic nerve hypoplasia, persistent fetal vasculature, microphthalmia, congenital cataracts, microcornea, corneal opacity and nystagmus. Most of these clinical features overlap with defects in the Norrin/β-catenin signalling pathway that is characterized by dysgenesis of the retinal and hyaloid vasculature. Our findings document Mendelian mutations within ATOH7 and imply a role for this molecule in the development of structures at the front as well as the back of the eye. This work also provides further insights into the function of ATOH7, especially its importance in retinal vascular development and hyaloid regression.
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Affiliation(s)
- Kamron Khan
- Leeds Institute of Molecular Medicine, University of Leeds, Leeds LS9 7TF, UK
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15
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Novel mutations affecting LRP5 splicing in patients with osteoporosis-pseudoglioma syndrome (OPPG). Eur J Hum Genet 2011; 19:875-81. [PMID: 21407258 DOI: 10.1038/ejhg.2011.42] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Osteoporosis-pseudoglioma sydrome (OPPG) is an autosomal recessive disorder with early-onset severe osteoporosis and blindness, caused by biallelic loss-of-function mutations in the low-density lipoprotein receptor-related protein 5 (LRP5) gene. Heterozygous carriers exhibit a milder bone phenotype. Only a few splice mutations in LRP5 have been published. We present clinical and genetic data for four patients with novel LRP5 mutations, three of which affect splicing. Patients were evaluated clinically and by radiography and bone densitometry. Genetic screening of LRP5 was performed on the basis of the clinical diagnosis of OPPG. Splice aberrances were confirmed by cDNA sequencing or exon trapping. The effect of one splice mutation on LRP5 protein function was studied. A novel splice-site mutation c.1584+4A>T abolished the donor splice site of exon 7 and activated a cryptic splice site, which led to an in-frame insertion of 21 amino acids (p.E528_V529ins21). Functional studies revealed severely impaired signal transduction presumably caused by defective intracellular transport of the mutated receptor. Exon trapping was used on two samples to confirm that splice-site mutations c.4112-2A>G and c.1015+1G>T caused splicing-out of exons 20 and 5, respectively. One patient carried a homozygous deletion of exon 4 causing the loss of exons 4 and 5, as demonstrated by cDNA analysis. Our results broaden the spectrum of mutations in LRP5 and provide the first functional data on splice aberrations.
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Nikopoulos K, Venselaar H, Collin RW, Riveiro-Alvarez R, Boonstra FN, Hooymans JM, Mukhopadhyay A, Shears D, van Bers M, de Wijs IJ, van Essen AJ, Sijmons RH, Tilanus MA, van Nouhuys CE, Ayuso C, Hoefsloot LH, Cremers FP. Overview of the mutation spectrum in familial exudative vitreoretinopathy and Norrie disease with identification of 21 novel variants in FZD4, LRP5, and NDP. Hum Mutat 2010; 31:656-66. [DOI: 10.1002/humu.21250] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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17
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Poulter JA, Ali M, Gilmour DF, Rice A, Kondo H, Hayashi K, Mackey DA, Kearns LS, Ruddle JB, Craig JE, Pierce EA, Downey LM, Mohamed MD, Markham AF, Inglehearn CF, Toomes C. Mutations in TSPAN12 cause autosomal-dominant familial exudative vitreoretinopathy. Am J Hum Genet 2010; 86:248-53. [PMID: 20159112 DOI: 10.1016/j.ajhg.2010.01.012] [Citation(s) in RCA: 132] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2009] [Revised: 01/08/2010] [Accepted: 01/11/2010] [Indexed: 12/01/2022] Open
Abstract
Familial exudative vitreoretinopathy (FEVR) is an inherited blinding disorder of the retinal vascular system. Although mutations in three genes (LRP5, FZD4, and NDP) are known to cause FEVR, these account for only a fraction of FEVR cases. The proteins encoded by these FEVR genes form part of a signaling complex that activates the Norrin-beta-catenin signaling pathway. Recently, through a large-scale reverse genetic screen in mice, Junge and colleagues identified an additional member of this signaling complex, Tspan12. Here, we report that mutations in TSPAN12 also cause autosomal-dominant FEVR. We describe seven mutations identified in a cohort of 70 FEVR patients in whom we had already excluded the known FEVR genes. This study provides further evidence for the importance of the Norrin-beta-catenin signaling pathway in the development of the retinal vasculature and also indicates that more FEVR genes remain to be identified.
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Affiliation(s)
- James A Poulter
- Leeds Institute of Molecular Medicine, St. James's University Hospital, Leeds, UK
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Robitaille JM, Wallace K, Zheng B, Beis MJ, Samuels M, Hoskin-Mott A, Guernsey DL. Phenotypic Overlap of Familial Exudative Vitreoretinopathy (FEVR) with Persistent Fetal Vasculature (PFV) Caused byFZD4Mutations in two Distinct Pedigrees. Ophthalmic Genet 2009; 30:23-30. [DOI: 10.1080/13816810802464312] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Abstract
Single nucleotide polymorphism (SNP) is the simplest form of DNA variation among individuals. These simple changes can be of transition or transversion type and they occur throughout the genome at a frequency of about one in 1,000 bp. They may be responsible for the diversity among individuals, genome evolution, the most common familial traits such as curly hair, interindividual differences in drug response, and complex and common diseases such as diabetes, obesity, hypertension, and psychiatric disorders. SNPs may change the encoded amino acids (nonsynonymous) or can be silent (synonymous) or simply occur in the noncoding regions. They may influence promoter activity (gene expression), messenger RNA (mRNA) conformation (stability), and subcellular localization of mRNAs and/or proteins and hence may produce disease. Therefore, identification of numerous variations in genes and analysis of their effects may lead to a better understanding of their impact on gene function and health of an individual. This improved knowledge may provide a starting point for the development of new, useful SNP markers for medical testing and a safer individualized medication to treat the most common devastating disorders. This will revolutionize the medical field in the future. To illustrate the effect of SNPs on gene function and phenotype, this minireview focuses on evidences revealing the impact of SNPs on the development and progression of three human eye disorders (Norrie disease, familial exudative vitreoretinopathy, and retinopathy of prematurity) that have overlapping clinical manifestations.
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Affiliation(s)
- Barkur S Shastry
- Department of Biological Sciences, Oakland University, Rochester, MI, USA
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20
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Verkaar F, van Rosmalen JWG, Blomenröhr M, van Koppen CJ, Blankesteijn WM, Smits JFM, Zaman GJR. G protein-independent cell-based assays for drug discovery on seven-transmembrane receptors. BIOTECHNOLOGY ANNUAL REVIEW 2008; 14:253-74. [PMID: 18606367 DOI: 10.1016/s1387-2656(08)00010-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Conventional cell-based assays for seven-transmembrane receptors, also known as G protein-coupled receptors, rely on the coupling of the ligand-bound receptor to heterotrimeric G proteins. New assay methods have become available that are not based on G protein activation, but that apply the molecular mechanism underlying the attenuation of G protein signaling mediated by beta-arrestin. beta-arrestin is a cytoplasmic protein that targets receptors to clathrin-coated endocytotic vesicles for degradation or recycling. This process has been visualized and quantified in high-content imaging assays using receptor- or beta-arrestin-chimeras with green fluorescent protein. Other assay methods use bioluminescence resonance energy transfer, enzyme fragment complementation, or a protease-activated transcriptional reporter gene, to measure receptor-beta-arrestin proximity. beta-arrestin recruitment assays have been applied successfully for receptors coupling to Galpha(q), Galpha(s) and Galpha(i) proteins, thus providing a generic assay platform for drug discovery on G protein-coupled receptors. The best understood signal transduction pathway elicited by the seven-transmembrane Frizzled receptors does not involve G proteins. The activation of Frizzleds by their cognate ligands of the Wnt family recruits the phosphoprotein dishevelled. Dishevelled regulates a protein complex involved in the destruction of beta-catenin. Activation of Frizzled blocks degradation of beta-catenin, which translocates to the nucleus to activate transcription of Wnt-responsive genes. The cytoplasm-to-nuclear translocation of beta-catenin forms the basis of several high-content assays to measure Wnt/Frizzled signal transduction. Interestingly, Frizzled receptors have recently been shown to internalize and to recruit beta-arrestin. This suggests that beta-arrestin recruitment assays may be applied for drug discovery on seven-transmembrane receptors beyond G protein-coupled receptors.
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Affiliation(s)
- Folkert Verkaar
- Molecular Pharmacology Unit, Organon BioSciences, Oss, The Netherlands
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Moderate reduction of Norrin signaling activity associated with the causative missense mutations identified in patients with familial exudative vitreoretinopathy. Hum Genet 2007; 122:615-23. [DOI: 10.1007/s00439-007-0438-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2007] [Accepted: 10/08/2007] [Indexed: 10/22/2022]
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Briggs T, Abdel-Salam G, Balicki M, Baxter P, Bertini E, Bishop N, Browne B, Chitayat D, Chong W, Eid M, Halliday W, Hughes I, Klusmann-Koy A, Kurian M, Nischal K, Rice G, Stephenson J, Surtees R, Talbot J, Tehrani N, Tolmie J, Toomes C, van der Knaap M, Crow Y. Cerebroretinal microangiopathy with calcifications and cysts (CRMCC). Am J Med Genet A 2007; 146A:182-90. [DOI: 10.1002/ajmg.a.32080] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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