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Yang M, Peng L, Lv L, Dai E, He Y, Zhao R, Li S. Characterization of a novel heterozygous frameshift variant in NDP gene that causes familial exudative vitreoretinopathy in female patients. Mol Genet Genomics 2024; 299:32. [PMID: 38472449 DOI: 10.1007/s00438-024-02128-3] [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: 03/14/2023] [Accepted: 10/28/2023] [Indexed: 03/14/2024]
Abstract
Familial exudative vitreoretinopathy (FEVR) is a severe inherited disease characterized by defective retinal vascular development. With genetic and clinical heterogeneity, FEVR can be inherited in different patterns and characterized by phenotypes ranging from moderate visual defects to complete vision loss. This study was conducted to unravel the genetic and functional etiology of a 4-month-old female FEVR patient. Targeted gene panel and Sanger sequencing were utilized for genetic evaluation. Luciferase assays, western blot, quantitive real-time PCR, and immunocytochemistry were performed to verify the functional defects in the identified candidate variant. Here, we report a 4-month-old girl with bilateral retinal folds and peripheral avascularization, and identified a novel frameshift heterozygous variant c.37dup (p.Leu13ProfsTer13) in NDP. In vitro experiments revealed that the Leu13ProfsTer13 variant led to a prominent decrease in protein levels instead of mRNA levels, resulting in compromised Norrin/β-catenin signaling activity. Human androgen receptor assay further revealed that a slight skewing of X chromosome inactivation could partially cause FEVR. Thus, the pathogenic mechanism by which heterozygous frameshift or nonsense variants in female carriers cause FEVR might largely result from a loss-of-function variant in one X chromosome allele and a slightly skewed X-inactivation. Further recruitment of more FEVR-affected females carrying NDP variants and genotype-phenotype correlation analysis can ultimately offer valuable information for the prognosis prediction of FEVR.
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Affiliation(s)
- Mu Yang
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, Department of Laboratory Medicine, Center for Medical Genetics, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, 32 The First Ring Road West 2, Chengdu, 610072, Sichuan, China
- Research Unit of Blindness Prevention, Chinese Academy of Medical Sciences (No. 2019RU026), Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, China
| | - Li Peng
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, Department of Laboratory Medicine, Center for Medical Genetics, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, 32 The First Ring Road West 2, Chengdu, 610072, Sichuan, China
- Research Unit of Blindness Prevention, Chinese Academy of Medical Sciences (No. 2019RU026), Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, China
| | - Liting Lv
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, Department of Laboratory Medicine, Center for Medical Genetics, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, 32 The First Ring Road West 2, Chengdu, 610072, Sichuan, China
- Research Unit of Blindness Prevention, Chinese Academy of Medical Sciences (No. 2019RU026), Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, China
| | - Erkuan Dai
- Department of Ophthalmology, Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yunqi He
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, Department of Laboratory Medicine, Center for Medical Genetics, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, 32 The First Ring Road West 2, Chengdu, 610072, Sichuan, China
- Research Unit of Blindness Prevention, Chinese Academy of Medical Sciences (No. 2019RU026), Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, China
| | - Rulian Zhao
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, Department of Laboratory Medicine, Center for Medical Genetics, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, 32 The First Ring Road West 2, Chengdu, 610072, Sichuan, China
- Research Unit of Blindness Prevention, Chinese Academy of Medical Sciences (No. 2019RU026), Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, China
| | - Shujin Li
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, Department of Laboratory Medicine, Center for Medical Genetics, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, 32 The First Ring Road West 2, Chengdu, 610072, Sichuan, China.
- Research Unit of Blindness Prevention, Chinese Academy of Medical Sciences (No. 2019RU026), Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, China.
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Huang L, Sun L, Li X, Li S, Zhang T, Zhang Z, Ding X. NDP-related retinopathies: clinical phenotype of female carriers. Br J Ophthalmol 2023; 107:1151-1155. [PMID: 35361573 PMCID: PMC10359507 DOI: 10.1136/bjophthalmol-2021-320084] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 03/13/2022] [Indexed: 11/03/2022]
Abstract
BACKGROUND/AIMS Norrin cysteine knot growth factor (NDP) located on the X chromosome, was previously reported to cause Norrie disease and familial exudative vitreoretinopathy (FEVR), which are blindness-causing ocular disorders, in males. In this study, we aimed to explore the clinical characteristics of female carriers with NDP mutations. METHODS Twelve female carriers from 11 unrelated families with pathogenic NDP mutations were recruited. Clinical data were collected from the NDP carriers. Comprehensive ocular examinations, including best corrected visual acuity, slit lamp examination, fundus photography and fundus fluorescein angiography (FFA) were evaluated. Targeted gene or whole exome sequencing was performed in the probands, and Sanger sequencing was performed to confirm NDP mutations in female carriers. RESULTS Of the 12 females, 1 (1/12, 8.3%) presented with decreased visual acuity and 11 (11/12, 91.7%) were asymptomatic. Based on the FFA, peripheral vascular changes were noted in 66.7% (16/24) of the eyes of 75.0% (9/12) of the carriers. A total of 33.3% (8/24) had typical FEVR phenotype, 33.3% (8/24) had mild vascular abnormalities and 33.3% (8/24) was unremarkable. In addition, predominant changes such as telangiectatic endings (66.7%), anomalous circumferential vessel (37.5%), supernumerary vascular branching (33.3%), fluorescein leakage (29.2%), avascular area (8.3%), retina fold (8.3%) and peripheral straightening of retinal vessels (33.3%) were noted. CONCLUSION Although NDP-related retinopathy is an X-linked recessive disorder, most of the female carriers of NDP exhibited clinical features of FEVR. Thus, timely examinations and lifelong monitoring should be conducted in the NDP female carriers.
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Affiliation(s)
- Li Huang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Limei Sun
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Xiaoyu Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Songshan Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Ting Zhang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Zhaotian Zhang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Xiaoyan Ding
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong, China
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De Silva SR, Arno G, Robson AG, Fakin A, Pontikos N, Mohamed MD, Bird AC, Moore AT, Michaelides M, Webster AR, Mahroo OA. The X-linked retinopathies: Physiological insights, pathogenic mechanisms, phenotypic features and novel therapies. Prog Retin Eye Res 2020; 82:100898. [PMID: 32860923 DOI: 10.1016/j.preteyeres.2020.100898] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 08/07/2020] [Accepted: 08/21/2020] [Indexed: 02/08/2023]
Abstract
X-linked retinopathies represent a significant proportion of monogenic retinal disease. They include progressive and stationary conditions, with and without syndromic features. Many are X-linked recessive, but several exhibit a phenotype in female carriers, which can help establish diagnosis and yield insights into disease mechanisms. The presence of affected carriers can misleadingly suggest autosomal dominant inheritance. Some disorders (such as RPGR-associated retinopathy) show diverse phenotypes from variants in the same gene and also highlight limitations of current genetic sequencing methods. X-linked disease frequently arises from loss of function, implying potential for benefit from gene replacement strategies. We review X-inactivation and X-linked inheritance, and explore burden of disease attributable to X-linked genes in our clinically and genetically characterised retinal disease cohort, finding correlation between gene transcript length and numbers of families. We list relevant genes and discuss key clinical features, disease mechanisms, carrier phenotypes and novel experimental therapies. We consider in detail the following: RPGR (associated with retinitis pigmentosa, cone and cone-rod dystrophy), RP2 (retinitis pigmentosa), CHM (choroideremia), RS1 (X-linked retinoschisis), NYX (complete congenital stationary night blindness (CSNB)), CACNA1F (incomplete CSNB), OPN1LW/OPN1MW (blue cone monochromacy, Bornholm eye disease, cone dystrophy), GPR143 (ocular albinism), COL4A5 (Alport syndrome), and NDP (Norrie disease and X-linked familial exudative vitreoretinopathy (FEVR)). We use a recently published transcriptome analysis to explore expression by cell-type and discuss insights from electrophysiology. In the final section, we present an algorithm for genes to consider in diagnosing males with non-syndromic X-linked retinopathy, summarise current experimental therapeutic approaches, and consider questions for future research.
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Affiliation(s)
- Samantha R De Silva
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Gavin Arno
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Anthony G Robson
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Ana Fakin
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK; Ljubljana University Medical Centre, Ljubljana, Slovenia
| | - Nikolas Pontikos
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Moin D Mohamed
- Department of Ophthalmology, Guy's & St Thomas' NHS Foundation Trust, London, UK
| | - Alan C Bird
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Anthony T Moore
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK; Department of Ophthalmology, UCSF School of Medicine, San Francisco, CA, USA
| | - Michel Michaelides
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Andrew R Webster
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Omar A Mahroo
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK; Department of Ophthalmology, Guy's & St Thomas' NHS Foundation Trust, London, UK; Section of Ophthalmology, King's College London, UK; Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK.
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Sowden JC, Kros CJ, Sirimanna T, Pagarkar W, Oluonye N, Henderson RH. Impact of sight and hearing loss in patients with Norrie disease: advantages of Dual Sensory clinics in patient care. BMJ Paediatr Open 2020; 4:e000781. [PMID: 33225082 PMCID: PMC7670942 DOI: 10.1136/bmjpo-2020-000781] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 09/30/2020] [Accepted: 10/05/2020] [Indexed: 11/17/2022] Open
Abstract
Norrie disease (ND) is a rare, X-linked condition of visual and auditory impairment, often presenting with additional neurological features and developmental delays of varying severity. While all affected patients are born blind, or lose their vision in infancy, progressive sensorineural hearing loss develops in the majority of cases and is typically detected in the second decade of life. A range of additional symptoms of ND, such as seizure disorders, typically appear from a young age, but it is difficult to predict the range of symptoms ND patients will experience. After growing up without vision, hearing loss represents the greatest worry for many patients with ND, as they may lose the ability to participate in previously enjoyed activities or to communicate with others. Dual sensory loss has a physical, psychosocial and financial impact on both patients with ND and their families. Routine monitoring of the condition is required in order to identify, treat and provide support for emerging health problems, leading to a large burden of medical appointments. Many patients need to travel long distances to meet with specialists, representing a further burden on time and finances. Additionally, the rare nature of dual sensory impairment in children means that few clinical environments are designed to meet their needs. Dual Sensory clinics are multidisciplinary environments designed for sensory-impaired children and have been suggested to alleviate the impact of diseases involving sensory loss such as ND. Here, we discuss the diagnosis, monitoring and management of ND and the impact it has on paediatric patients and their caregivers. We describe the potential for dual sensory clinics to reduce disease burden through providing an appropriate clinical environment, access to multiple clinical experts in one visit, and ease of monitoring for patients with ND.
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Affiliation(s)
- Jane C Sowden
- Developmental Biology and Cancer Department, UCL Great Ormond Street Institute of Child Health, London, London, UK
| | - Corné J Kros
- School of Life Sciences, University of Sussex, Brighton, Brighton and Hove, UK
| | - Tony Sirimanna
- Great Ormond Street Hospital for Children, London, London, UK
| | | | - Ngozi Oluonye
- Wolfson Neurodisability Service, Great Ormond Street Hospital for Children, London, London, UK
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Rodríguez-Muñoz A, García-García G, Menor F, Millán JM, Tomás-Vila M, Jaijo T. The importance of biochemical and genetic findings in the diagnosis of atypical Norrie disease. Clin Chem Lab Med 2019; 56:229-235. [PMID: 28742514 DOI: 10.1515/cclm-2017-0226] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 06/25/2017] [Indexed: 11/15/2022]
Abstract
BACKGROUND Norrie disease (ND) is a rare X-linked disorder characterized by bilateral congenital blindness. ND is caused by a mutation in the Norrie disease pseudoglioma (NDP) gene, which encodes a 133-amino acid protein called norrin. Intragenic deletions including NDP and adjacent genes have been identified in ND patients with a more severe neurologic phenotype. We report the biochemical, molecular, clinical and radiological features of two unrelated affected males with a deletion including NDP and MAO genes. METHODS Biochemical and genetic analyses were performed to understand the atypical phenotype and radiological findings. Biogenic amines in cerebrospinal fluid (CSF) were measured by high-performance liquid chromatography. The coding exons of NDP gene were amplified by polymerase chain reaction. Multiplex ligation-dependent probe amplification and chromosomal microarray were carried out on both affected males. Computed tomography and magnetic resonance imaging were performed on the two patients. RESULTS In one patient, the serotonin and catecholamine metabolite levels in CSF were virtually undetectable. In both patients, genetic studies revealed microdeletions in the Xp11.3 region, involving the NDP, MAOA and MAOB genes. Radiological examination demonstrated brain and cerebellar atrophy. CONCLUSIONS We suggest that alterations caused by MAO deficit may remain during the first years of life. Clinical phenotype, biochemical findings and neuroimaging can guide the genetic study in patients with atypical ND and help us to a better understanding of this disease.
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Affiliation(s)
- Ana Rodríguez-Muñoz
- Grupo de Investigación en Biomedicina Molecular, Celular y Genómica, Instituto de Investigación Sanitaria La Fe, Valencia, Spain
| | - Gema García-García
- Grupo de Investigación en Biomedicina Molecular, Celular y Genómica, Instituto de Investigación Sanitaria La Fe, Valencia, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Valencia, Spain
| | - Francisco Menor
- Radiología Infantil, Hospital Universitari i Politecnic La Fe, Valencia, Spain
| | - José M Millán
- Grupo de Investigación en Biomedicina Molecular, Celular y Genómica, Instituto de Investigación Sanitaria La Fe, Valencia, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Valencia, Spain
| | - Miguel Tomás-Vila
- Neuropediatría, Hospital Universitari i Politecnic La Fe, Valencia, Spain
| | - Teresa Jaijo
- Grupo de Investigación en Biomedicina Molecular, Celular y Genómica, Instituto de Investigación Sanitaria La Fe, Valencia, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Valencia, Spain.,Unidad de Genética y Diagnóstico Prenatal, Hospital Universitari i Politecnic La Fe, Valencia, Spain
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Cação G, Garrido C, Miranda V, Pinto-Basto J, Chaves J, Chorão R. Refractory epilepsy in Norrie disease. Neurol Sci 2018; 39:1631-1633. [DOI: 10.1007/s10072-018-3428-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2018] [Accepted: 04/23/2018] [Indexed: 10/17/2022]
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7
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Leivada E. Vision, language and a protective mechanism towards psychosis. Neurosci Lett 2016; 617:178-81. [PMID: 26899155 DOI: 10.1016/j.neulet.2016.02.024] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Revised: 01/29/2016] [Accepted: 02/11/2016] [Indexed: 02/07/2023]
Abstract
The absence of co-occurrence of schizophrenia with congenital/early blindness (CB) has led to the claim that CB confers protection against schizophrenia. It has recently been shown that the protective effects are particularly reinforced in cases of CB of cortical origin, since cases of CB of peripheral origin and schizophrenia in fact exist. The present work shows that the protection extends to psychosis more broadly and describes the brain basis of the protective mechanism and its relation to the language faculty and the language areas of the brain.
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Affiliation(s)
- Evelina Leivada
- Cyprus Acquisition Team, University of Cyprus, 75 Kallipoleos, P.O. Box 20537, 1087 Nicosia, Cyprus.
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Okumura A, Arai E, Kitamura Y, Abe S, Ikeno M, Fujimaki T, Yamamoto T, Shimizu T. Epilepsy phenotypes in siblings with Norrie disease. Brain Dev 2015; 37:978-82. [PMID: 25944760 DOI: 10.1016/j.braindev.2015.04.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Revised: 04/01/2015] [Accepted: 04/03/2015] [Indexed: 10/23/2022]
Abstract
Norrie disease is an X-linked recessive disorder that is characterized by congenital blindness. Although epileptic seizures are observed in some patients with Norrie disease, little is known about this phenomenon. Here, we report the manifestation of epilepsy in siblings with Norrie disease to increase our knowledge of epilepsy in this condition. Three brothers with congenital blindness were diagnosed with Norrie disease after genetic analyses indicated the deletion of exon 2 of the NDP gene. The eldest brother had suffered from epileptic seizures since the age of 11years, and his seizures were resistant to antiepileptic drugs. Although the second brother had no epileptic seizures, the youngest sibling had experiences epileptic seizures since the age of 8years. His seizures were controlled using lamotrigine and levetiracetam. An electroencephalography (EEG) revealed epileptiform discharges in the occipital areas in all three brothers. A study of these patients will increase our knowledge of epilepsy in patients with Norrie disease.
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Affiliation(s)
- Akihisa Okumura
- Department of Pediatrics, Aichi Medical University, Japan; Department of Pediatrics, Juntendo University, Faculty of Medicine, Japan.
| | - Eisuke Arai
- Department of Ophthalmology, Juntendo University, Faculty of Medicine, Japan
| | - Yuri Kitamura
- Department of Pediatrics, Juntendo University, Faculty of Medicine, Japan
| | - Shinpei Abe
- Department of Pediatrics, Juntendo University, Faculty of Medicine, Japan
| | - Mitsuru Ikeno
- Department of Pediatrics, Juntendo University, Faculty of Medicine, Japan
| | - Takuro Fujimaki
- Department of Ophthalmology, Juntendo University, Faculty of Medicine, Japan
| | - Toshiyuki Yamamoto
- Tokyo Women's Medical University, Institute for Integrated Medical Sciences, Japan
| | - Toshiaki Shimizu
- Department of Pediatrics, Juntendo University, Faculty of Medicine, Japan
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Smith SE, Mullen TE, Graham D, Sims KB, Rehm HL. Norrie disease: Extraocular clinical manifestations in 56 patients. Am J Med Genet A 2012; 158A:1909-17. [DOI: 10.1002/ajmg.a.35469] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Accepted: 04/16/2012] [Indexed: 11/06/2022]
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10
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Waryah AM, Ahmed ZM, Bhinder MA, Binder MA, Choo DI, Sisk RA, Shahzad M, Khan SN, Friedman TB, Riazuddin S, Riazuddin S. Molecular and clinical studies of X-linked deafness among Pakistani families. J Hum Genet 2011; 56:534-40. [PMID: 21633365 PMCID: PMC3143270 DOI: 10.1038/jhg.2011.55] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
There are 68 sex-linked syndromes that include hearing loss as one feature and five sex-linked nonsyndromic deafness loci listed in the OMIM database. The possibility of additional such sex-linked loci was explored by ascertaining three unrelated Pakistani families (PKDF536, PKDF1132, PKDF740) segregating X-linked recessive deafness. Sequence analysis of POU3F4 (DFN3) in affected members of families PKDF536 and PKDF1132 revealed two novel nonsense mutations, p.Q136X and p.W114X, respectively. Family PKDF740 is segregating congenital blindness, mild to profound progressive hearing loss that is characteristic of Norrie disease (MIM#310600). Sequence analysis of NDP among affected members of this family revealed a novel single nucleotide deletion c.49delG causing a frameshift and premature truncation (p.V17fsX1) of the encoded protein. These mutations were not found in 150 normal DNA samples. Identification of pathogenic alleles causing X-linked recessive deafness will improve molecular diagnosis, genetic counseling, and molecular epidemiology of hearing loss among Pakistanis.
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Affiliation(s)
- Ali M Waryah
- National Center of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
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Whibley A, Urquhart J, Dore J, Willatt L, Parkin G, Gaunt L, Black G, Donnai D, Raymond FL. Deletion of MAOA and MAOB in a male patient causes severe developmental delay, intermittent hypotonia and stereotypical hand movements. Eur J Hum Genet 2010; 18:1095-9. [PMID: 20485326 DOI: 10.1038/ejhg.2010.41] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Monoamine oxidases (MAO-A and MAO-B) have a key role in the degradation of amine neurotransmitters, such as dopamine, norepinephrine and serotonin. We identified an inherited 240 kb deletion on Xp11.3-p11.4, which encompasses both monoamine oxidase genes but, unlike other published reports, does not affect the adjacent Norrie disease gene (NDP). The brothers who inherited the deletion, and thus have no monoamine oxidase function, presented with severe developmental delay, intermittent hypotonia and stereotypical hand movements. The clinical features accord with published reports of larger microdeletions and selective MAO-A and MAO-B deficiencies in humans and mouse models and suggest considerable functional compensation between MAO-A and MAO-B under normal conditions.
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Affiliation(s)
- Annabel Whibley
- Department of Medical Genetics, Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
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Berger W, Kloeckener-Gruissem B, Neidhardt J. The molecular basis of human retinal and vitreoretinal diseases. Prog Retin Eye Res 2010; 29:335-75. [PMID: 20362068 DOI: 10.1016/j.preteyeres.2010.03.004] [Citation(s) in RCA: 404] [Impact Index Per Article: 28.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
During the last two to three decades, a large body of work has revealed the molecular basis of many human disorders, including retinal and vitreoretinal degenerations and dysfunctions. Although belonging to the group of orphan diseases, they affect probably more than two million people worldwide. Most excitingly, treatment of a particular form of congenital retinal degeneration is now possible. A major advantage for treatment is the unique structure and accessibility of the eye and its different components, including the vitreous and retina. Knowledge of the many different eye diseases affecting retinal structure and function (night and colour blindness, retinitis pigmentosa, cone and cone rod dystrophies, photoreceptor dysfunctions, as well as vitreoretinal traits) is critical for future therapeutic development. We have attempted to present a comprehensive picture of these disorders, including biological, clinical, genetic and molecular information. The structural organization of the review leads the reader through non-syndromic and syndromic forms of (i) rod dominated diseases, (ii) cone dominated diseases, (iii) generalized retinal degenerations and (iv) vitreoretinal disorders, caused by mutations in more than 165 genes. Clinical variability and genetic heterogeneity have an important impact on genetic testing and counselling of affected families. As phenotypes do not always correlate with the respective genotypes, it is of utmost importance that clinicians, geneticists, counsellors, diagnostic laboratories and basic researchers understand the relationships between phenotypic manifestations and specific genes, as well as mutations and pathophysiologic mechanisms. We discuss future perspectives.
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Affiliation(s)
- Wolfgang Berger
- Division of Medical Molecular Genetics and Gene Diagnostics, Institute of Medical Genetics, University of Zurich, Schorenstrasse 16, CH-8603 Schwerzenbach, Switzerland.
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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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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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Luhmann UFO, Neidhardt J, Kloeckener-Gruissem B, Schäfer NF, Glaus E, Feil S, Berger W. Vascular changes in the cerebellum of Norrin /Ndph knockout mice correlate with high expression of Norrin and Frizzled-4. Eur J Neurosci 2008; 27:2619-28. [PMID: 18547247 DOI: 10.1111/j.1460-9568.2008.06237.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
X-linked Norrie disease, familial exudative vitreoretinopathy (FEVR), Coat's disease and retinopathy of prematurity are severe human eye diseases and can all be caused by mutations in the Norrie disease pseudoglioma gene. They all show vascular defects and characteristic features of retinal hypoxia. Only Norrie disease displays additional neurological symptoms, which are sensorineural hearing loss and mental retardation. In the present study, we analysed transcript levels of the ligand Norrin (Ndph) and its two receptors Frizzled-4 (Fzd4) and LDL-related protein receptor 5 (Lrp5) in six different brain regions (cerebellum, cortex, hippocampus, olfactory bulb, pituitary and brain stem) of 6- to 8-month-old wild-type and Ndph knockout mice by quantitative real-time PCR. No effect of the Ndph knockout allele on Fzd4 or Lrp5 receptor expression was found. Furthermore, no alterations of the transcript levels of three hypoxia-regulated angiogenic factors (Vegfa, Itgrb3 and Tie1) were observed in the absence of Norrin. Interestingly, we identified significant differences in Ndph, Fzd4 and Lrp5 transcript levels in brain regions of wild-type mice and observed highest expression of Norrin and frizzled-4 in cerebellum. Transcript analyses were correlated with morphological data obtained from cerebellum and immunohistochemical studies of blood vessels in different brain regions. Vessel density was reduced in the cerebellum of Ndph knockout mice but the number of Purkinje and granular cells was not altered. This provides the first description of a brain phenotype in Ndph knockout mice, which will help to elucidate the role of Norrin in the brain.
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Affiliation(s)
- Ulrich F O Luhmann
- Division of Medical Molecular Genetics & Gene Diagnostics, Institute of Medical Genetics, University of Zurich, Schorenstrasse 16, CH-8603 Schwerzenbach, Switzerland
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Khan AO, Aldahmesh MA, Meyer B. Correlation of Ophthalmic Examination with Carrier Status in Females Potentially Harboring a Severe Norrie Disease Gene Mutation. Ophthalmology 2008; 115:730-3. [DOI: 10.1016/j.ophtha.2007.04.064] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2006] [Revised: 04/22/2007] [Accepted: 04/23/2007] [Indexed: 10/22/2022] Open
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Lev D, Weigl Y, Hasan M, Gak E, Davidovich M, Vinkler C, Leshinsky-Silver E, Lerman-Sagie T, Watemberg N. A novel missense mutation in theNDP gene in a child with Norrie disease and severe neurological involvement including infantile spasms. Am J Med Genet A 2007; 143A:921-4. [PMID: 17334993 DOI: 10.1002/ajmg.a.31531] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Norrie disease (ND) is a rare X-linked recessive disorder characterized by congenital blindness and in some cases, mental retardation and deafness. Other neurological complications, particularly epilepsy, are rare. We report on a novel mutation identified in a patient with ND and profound mental retardation. The patient was diagnosed at the age of 6 months due to congenital blindness. At the age of 8 months he developed infantile spasms, which were diagnosed at 11 months as his EEG demonstrated hypsarrhythmia. Mutation analysis of the ND gene (NDP) of the affected child and his mother revealed a novel missense mutation at position c.134T > A resulting in amino acid change at codon V45E. To the best of our knowledge, such severe neurological involvement has not been previously reported in ND patients. The severity of the phenotype may suggest the functional importance of this site of the NDP gene.
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Affiliation(s)
- Dorit Lev
- Institute of Medical Genetics, Wolfson Medical Center, Holon, Israel.
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