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Hotta Y, Torii K, Takayama M. Ocular genetics in the Japanese population. Jpn J Ophthalmol 2024; 68:401-418. [PMID: 39271608 PMCID: PMC11420330 DOI: 10.1007/s10384-024-01109-8] [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: 04/09/2024] [Accepted: 07/03/2024] [Indexed: 09/15/2024]
Abstract
In today's globalized society, ophthalmologists can examine people of different ethnicities regardless of where they live. The frequency of disease-causing genes varies according to a patient's ethnic background. We explain genetic findings for Japanese patients with inherited eye diseases. Ocular genetics has made great advances over the past 30 years. For example, detecting mutations at nucleotide position 11778 in mitochondrial DNA was useful in the genetic diagnosis of Leber's hereditary optic neuropathy (LHON). I evaluated the genotype-phenotype relationship in cases of corneal dystrophy and inherited retinal dystrophy (IRD). I identified the entire exon sequence of the eyes shut homolog (EYS) gene in patients with autosomal recessive retinitis pigmentosa (RP). EYS gene mutations are the most frequent cause of autosomal recessive RP. RPGRIP1 may be a common causative gene with early-onset severe retinal dystrophy, including Leber congenital amaurosis. However, some genes have complex structures that are difficult to analyze, including the OPN1LW/OPN1MW gene cluster in blue cone monochromacy and the IKBKG/NEMO genes in incontinentia pigmenti. This review will also present two cases with uniparental disomy, a case of IRD with double mutations, and a case with RP complicated with LHON-like neuropathy. Precise understanding of the effects of genetic variants may reveal differences in the clinical characteristics of patients with the same variant. When starting genome medicine, accurately diagnosing the patient, making accurate prediction, determining the genetic pattern, and providing genetic counseling are important. Above all, that both the doctors and patients understand genetic diseases correctly is important.
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Affiliation(s)
- Yoshihiro Hotta
- Hamamatsu University School of Medicine, 1-20-1 Handayama, Chuo-ku, Hamamatsu city, Shizuoka, 431-3192, Japan.
| | - Kaoruko Torii
- Hamamatsu University School of Medicine, 1-20-1 Handayama, Chuo-ku, Hamamatsu city, Shizuoka, 431-3192, Japan
| | - Masakazu Takayama
- Hamamatsu University School of Medicine, 1-20-1 Handayama, Chuo-ku, Hamamatsu city, Shizuoka, 431-3192, Japan
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2
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Stepanova A, Ogorodova N, Kadyshev V, Shchagina O, Kutsev S, Polyakov A. A Molecular Genetic Analysis of RPE65-Associated Forms of Inherited Retinal Degenerations in the Russian Federation. Genes (Basel) 2023; 14:2056. [PMID: 38002999 PMCID: PMC10671290 DOI: 10.3390/genes14112056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 10/26/2023] [Accepted: 11/01/2023] [Indexed: 11/26/2023] Open
Abstract
Pathogenic variants in the RPE65 gene cause the only known form of inherited retinal degenerations (IRDs) that are prone to gene therapy. The current study is aimed at the evaluation of the prevalence of RPE65-associated retinopathy in the Russian Federation, the characterization of known variants in the RPE65 gene, and the establishment of the specificities of the mutation spectrum in Russian patients. METHODS The analysis was carried out on blood samples obtained from 1053 non-related IRDs patients. The analysis, which consisted of 211 genes, was carried out based on the method of massive parallel sequencing (MPS) for all probands. Variant validation, as well as biallelic status verification, were carried out using direct automated Sanger sequencing. The number of copies of RPE65 exons 1-14 was analyzed with quantitative MLPA using an MRC-Holland SALSA MLPA probemix. RESULTS Out of 1053 non-related patients, a molecular genetic diagnosis of IRDs has been confirmed in 474 cases, including 25 (5.3%) patients with RPE65-associated retinopathy. We detected 26 variants in the RPE65 gene, nine of which have not been previously described in the literature. The most common mutations in the Russian population were c.304G>T/p.(Glu102*), c.370C>T/p.(Arg124*), and c.272G>A/p.(Arg91Gln), which comprised 41.8% of all affected chromosomes. CONCLUSIONS The current study shows that pathogenic variants in the RPE65 gene contribute significantly to the pathogenesis of IRDs and comprise 5.3% of all patients with a confirmed molecular genetic diagnosis. This study allowed for the formation of a cohort for target therapy of the disorder; such therapy has already been carried out for some patients.
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Affiliation(s)
- Anna Stepanova
- Research Centre for Medical Genetics, Moscow 115478, Russia
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3
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Jain R, Rabea F, Alfalasi R, Elabiary MW, Abou Tayoun A. Paternal Uniparental Isodisomy of Chromosome 2 in a Patient with Congenital Hypothyroidism: Ruling Out Recessive Inheritance or a Kinship/Laboratory Sequencing Error. J Appl Lab Med 2023; 8:993-999. [PMID: 37478349 DOI: 10.1093/jalm/jfad039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 04/24/2023] [Indexed: 07/23/2023]
Affiliation(s)
- Ruchi Jain
- Al Jalila Genomics Center of Excellence, Al Jalila Children's Specialty Hospital, Dubai, United Arab Emirates
| | - Fatima Rabea
- College of Medicine, Mohammed Bin Rashid University of Medicine and Health Sciences, Dubai, United Arab Emirates
| | - Roudha Alfalasi
- Al Jalila Genomics Center of Excellence, Al Jalila Children's Specialty Hospital, Dubai, United Arab Emirates
| | - Mohamed Wasfy Elabiary
- College of Medicine, Mohammed Bin Rashid University of Medicine and Health Sciences, Dubai, United Arab Emirates
- Department of Endocrinology, Al Jalila Children's Specialty Hospital, Dubai, United Arab Emirates
| | - Ahmad Abou Tayoun
- Al Jalila Genomics Center of Excellence, Al Jalila Children's Specialty Hospital, Dubai, United Arab Emirates
- Center for Genomic Discovery, Mohammed Bin Rashid University of Medicine and Health Sciences, Dubai, United Arab Emirates
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4
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Han J, Joo K, Kim US, Woo SJ, Lee EK, Lee JY, Park TK, Kim SJ, Byeon SH. Voretigene Neparvovec for the Treatment of RPE65-associated Retinal Dystrophy: Consensus and Recommendations from the Korea RPE65-IRD Consensus Paper Committee. KOREAN JOURNAL OF OPHTHALMOLOGY 2023; 37:166-186. [PMID: 36950921 PMCID: PMC10151174 DOI: 10.3341/kjo.2023.0008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 03/12/2023] [Accepted: 03/15/2023] [Indexed: 03/24/2023] Open
Abstract
Mutations in the RPE65 gene, associated with Leber congenital amaurosis, early-onset severe retinal dystrophy, and retinitis pigmentosa, gained growing attention since gene therapy for patients with RPE65-associated retinal dystrophy is available in clinical practice. RPE65 gene accounts for a very small proportion of patients with inherited retinal degeneration, especially Asian patients. Because RPE65-associated retinal dystrophy shares common clinical characteristics, such as early-onset severe nyctalopia, nystagmus, low vision, and progressive visual field constriction, with retinitis pigmentosa by other genetic mutations, appropriate genetic testing is essential to make a correct diagnosis. Also, fundus abnormalities can be minimal in early childhood, and the phenotype is highly variable depending on the type of mutations in RPE65-associated retinal dystrophy, which makes a diagnostic difficulty. The aim of this paper is to review the epidemiology of RPE65-associated retinal dystrophy, mutation spectrum, genetic diagnosis, clinical characteristics, and voretigene neparvovec, a gene therapy product for the treatment of RPE65-related retinal dystrophy.
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Affiliation(s)
- Jinu Han
- Institute of Vision Research, Department of Ophthalmology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul,
Korea
| | - Kwangsic Joo
- Department of Ophthalmology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam,
Korea
| | - Ungsoo Samuel Kim
- Department of Ophthalmology, Chung-Ang University Gwangmyeong Hospital, Gwangmyeong,
Korea
| | - Se Joon Woo
- Department of Ophthalmology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam,
Korea
| | - Eun Kyoung Lee
- Department of Ophthalmology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul,
Korea
| | - Joo Yong Lee
- Department of Ophthalmology, Asan Medical Center, University of Ulsan College of Medicine, Seoul,
Korea
| | - Tae Kwann Park
- Department of Ophthalmology, Soonchunhyang University Bucheon Hospital, Bucheon,
Korea
| | - Sang Jin Kim
- Department of Ophthalmology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul,
Korea
| | - Suk Ho Byeon
- Institute of Vision Research, Department of Ophthalmology, Severance Hospital, Yonsei University College of Medicine, Seoul,
Korea
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5
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Francia S, Shmal D, Di Marco S, Chiaravalli G, Maya-Vetencourt JF, Mantero G, Michetti C, Cupini S, Manfredi G, DiFrancesco ML, Rocchi A, Perotto S, Attanasio M, Sacco R, Bisti S, Mete M, Pertile G, Lanzani G, Colombo E, Benfenati F. Light-induced charge generation in polymeric nanoparticles restores vision in advanced-stage retinitis pigmentosa rats. Nat Commun 2022; 13:3677. [PMID: 35760799 PMCID: PMC9237035 DOI: 10.1038/s41467-022-31368-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 06/14/2022] [Indexed: 12/16/2022] Open
Abstract
Retinal dystrophies such as Retinitis pigmentosa are among the most prevalent causes of inherited legal blindness, for which treatments are in demand. Retinal prostheses have been developed to stimulate the inner retinal network that, initially spared by degeneration, deteriorates in the late stages of the disease. We recently reported that conjugated polymer nanoparticles persistently rescue visual activities after a single subretinal injection in the Royal College of Surgeons rat model of Retinitis pigmentosa. Here we demonstrate that conjugated polymer nanoparticles can reinstate physiological signals at the cortical level and visually driven activities when microinjected in 10-months-old Royal College of Surgeons rats bearing fully light-insensitive retinas. The extent of visual restoration positively correlates with the nanoparticle density and hybrid contacts with second-order retinal neurons. The results establish the functional role of organic photovoltaic nanoparticles in restoring visual activities in fully degenerate retinas with intense inner retina rewiring, a stage of the disease in which patients are subjected to prosthetic interventions. Retinal dystrophies such as Retinitis pigmentosa are among the most prevalent causes of inherited incurable legal blindness. Here the authors demonstrate that conjugated polymer nanoparticles reinstate visual functions in aged rats with fully degenerated and rewired retinas.
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Affiliation(s)
- S Francia
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genova, Italy.,IRCCS Ospedale Policlinico San Martino, Genova, Italy
| | - D Shmal
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genova, Italy.,Department of Experimental Medicine, University of Genova, Genova, Italy
| | - S Di Marco
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genova, Italy.,IRCCS Ospedale Policlinico San Martino, Genova, Italy
| | - G Chiaravalli
- Center for Nanoscience and Technology, Istituto Italiano di Tecnologia, Milano, Italy
| | - J F Maya-Vetencourt
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genova, Italy.,Department of Biology, University of Pisa, Pisa, Italy
| | - G Mantero
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genova, Italy.,Department of Experimental Medicine, University of Genova, Genova, Italy
| | - C Michetti
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genova, Italy.,Department of Experimental Medicine, University of Genova, Genova, Italy
| | - S Cupini
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genova, Italy.,Department of Experimental Medicine, University of Genova, Genova, Italy
| | - G Manfredi
- Center for Nanoscience and Technology, Istituto Italiano di Tecnologia, Milano, Italy.,Novavido s.r.l., Bologna, Italy
| | - M L DiFrancesco
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genova, Italy.,IRCCS Ospedale Policlinico San Martino, Genova, Italy
| | - A Rocchi
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genova, Italy
| | - S Perotto
- Center for Nanoscience and Technology, Istituto Italiano di Tecnologia, Milano, Italy
| | - M Attanasio
- Department of Ophthalmology, IRCCS Sacrocuore Don Calabria Hospital, Negrar, Verona, Italy
| | - R Sacco
- Department of Mathematics, Politecnico di Milano, Milano, Italy
| | - S Bisti
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genova, Italy
| | - M Mete
- Department of Ophthalmology, IRCCS Sacrocuore Don Calabria Hospital, Negrar, Verona, Italy
| | - G Pertile
- Department of Ophthalmology, IRCCS Sacrocuore Don Calabria Hospital, Negrar, Verona, Italy
| | - G Lanzani
- Center for Nanoscience and Technology, Istituto Italiano di Tecnologia, Milano, Italy. .,Department of Physics, Politecnico di Milano, Milan, Italy.
| | - E Colombo
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genova, Italy.,IRCCS Ospedale Policlinico San Martino, Genova, Italy
| | - F Benfenati
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genova, Italy. .,IRCCS Ospedale Policlinico San Martino, Genova, Italy.
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6
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Bedoukian EC, O'Neil EC, Aleman TS. RP1-associated recessive retinitis pigmentosa caused by paternal uniparental disomy. Ophthalmic Genet 2022; 43:555-560. [PMID: 35484846 DOI: 10.1080/13816810.2022.2062389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
BACKGROUND We report on a patient with a juvenile-onset inherited retinal degeneration (IRD) associated with homozygous RP1 mutations inherited by uniparental disomy (UPD). MATERIAL AND METHODS A 6-year-old healthy girl failed school vision screening and was diagnosed with a bull's eye maculopathy. She underwent complete ophthalmic examination, full-field electroretinograms (ERG), kinetic fields, full-field sensitivity testing (FST), and retinal imaging with spectral domain optical coherence tomography (SD-OCT) and near-infrared (NIR) and short wavelength (SW) fundus autofluorescence (FAF). RESULTS Visual acuities were relatively preserved (20/30+). There was subtle foveal depigmentation but an otherwise normal fundus examination. SD-OCT revealed a relatively preserved fovea with thinning of the photoreceptor outer nuclear layer with increasing distance from the foveal center coinciding with marked attenuation of the NIR and less marked loss of the SW-FAF signal. ERGs were non-detectable. Kinetic visual fields were generally full to large (V-4e) target but constricted to ~10°of eccentricity to I-4e stimuli. Dark-adapted thresholds by FST were rod-mediated and elevated by ~2 log units. Homozygous pathogenic mutations in RP1 (c.1720_1721del; p.Ser574Asnfs*8) were identified. Family member testing revealed father and siblings to be unaffected carriers; the mother carried wild-type alleles. Further testing suggested UPD of chromosome 8. CONCLUSION This report adds support to UPD as a mechanism of inheritance in IRDs and stresses the importance of familial testing for genetic diagnosis and counseling. Consistent with earlier descriptions of autosomal recessive RP1-IRDs our patient showed an early rod and cone photoreceptor degeneration.
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Affiliation(s)
- Emma C Bedoukian
- Division of Ophthalmology, Children's Hospital of Philadelphia.,Roberts Individualized Medical Genetics Center, Children's Hospital of Philadelphia, Pennsylvania, USA
| | - Erin C O'Neil
- Division of Ophthalmology, Children's Hospital of Philadelphia.,Center for Advanced Retinal and Ocular Therapeutics
| | - Tomas S Aleman
- Division of Ophthalmology, Children's Hospital of Philadelphia.,Center for Advanced Retinal and Ocular Therapeutics.,Scheie Eye Institute at the Perelman Center for Advanced Medicine, Department of Ophthalmology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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7
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Tachibana N, Hosono K, Nomura S, Arai S, Torii K, Kurata K, Sato M, Shimakawa S, Azuma N, Ogata T, Wada Y, Okamoto N, Saitsu H, Nishina S, Hotta Y. Maternal Uniparental Isodisomy of Chromosome 4 and 8 in Patients with Retinal Dystrophy: SRD5A3-Congenital Disorders of Glycosylation and RP1-Related Retinitis Pigmentosa. Genes (Basel) 2022; 13:genes13020359. [PMID: 35205402 PMCID: PMC8872353 DOI: 10.3390/genes13020359] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 02/08/2022] [Accepted: 02/10/2022] [Indexed: 01/27/2023] Open
Abstract
Purpose: Uniparental disomy (UPD) is a rare chromosomal abnormality. We performed whole-exosome sequencing (WES) in cases of early-onset retinal dystrophy and identified two cases likely caused by UPD. Herein, we report these two cases and attempt to clarify the clinical picture of retinal dystrophies caused by UPD. Methods: WES analysis was performed for two patients and their parents, who were not consanguineous. Functional analysis was performed in cases suspected of congenital disorders of glycosylation (CDG). We obtained clinical case data and reviewed the literature. Results: In case 1, a novel c.57G>C, p.(Trp19Cys) variant in SRD5A3 was detected homozygously. Genetic analysis suggested a maternal UPD on chromosome 4, and functional analysis confirmed CDG. Clinical findings showed early-onset retinal dystrophy, intellectual disability, and epilepsy. In case 2, an Alu insertion (c.4052_4053ins328, p.[Tyr1352Alafs]) in RP1 was detected homozygously. Maternal UPD on chromosome 8 was suspected. The clinical picture was consistent with RP1-related retinitis pigmentosa. Although the clinical features of retinal dystrophy by UPD may vary, most cases present with childhood onset. Conclusions: There have been limited reports of retinal dystrophy caused by UPD, suggesting that it is rare. Genetic counseling may be encouraged in pediatric cases of retinal dystrophy.
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Affiliation(s)
- Nobutaka Tachibana
- Department of Ophthalmology, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan; (N.T.); (K.H.); (S.N.); (S.A.); (K.T.); (K.K.); (M.S.)
| | - Katsuhiro Hosono
- Department of Ophthalmology, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan; (N.T.); (K.H.); (S.N.); (S.A.); (K.T.); (K.K.); (M.S.)
| | - Shuhei Nomura
- Department of Ophthalmology, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan; (N.T.); (K.H.); (S.N.); (S.A.); (K.T.); (K.K.); (M.S.)
| | - Shinji Arai
- Department of Ophthalmology, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan; (N.T.); (K.H.); (S.N.); (S.A.); (K.T.); (K.K.); (M.S.)
| | - Kaoruko Torii
- Department of Ophthalmology, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan; (N.T.); (K.H.); (S.N.); (S.A.); (K.T.); (K.K.); (M.S.)
| | - Kentaro Kurata
- Department of Ophthalmology, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan; (N.T.); (K.H.); (S.N.); (S.A.); (K.T.); (K.K.); (M.S.)
| | - Miho Sato
- Department of Ophthalmology, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan; (N.T.); (K.H.); (S.N.); (S.A.); (K.T.); (K.K.); (M.S.)
| | - Shuichi Shimakawa
- Department of Pediatrics, Osaka Medical and Pharmaceutical University Hospital, Takatsuki 569-8686, Japan;
| | - Noriyuki Azuma
- National Center for Child Health and Development, Department of Ophthalmology and Laboratory for Visual Science, Tokyo 157-8535, Japan; (N.A.); (S.N.)
| | - Tsutomu Ogata
- Department of Biochemistry, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan; (T.O.); (H.S.)
- Hamamatsu Medical Center, Department of Pediatrics, Hamamatsu 432-8580, Japan
| | - Yoshinao Wada
- Department of Molecular Medicine, Osaka Women’s and Children’s Hospital, Izumi 594-1101, Japan; (Y.W.); (N.O.)
| | - Nobuhiko Okamoto
- Department of Molecular Medicine, Osaka Women’s and Children’s Hospital, Izumi 594-1101, Japan; (Y.W.); (N.O.)
- Department of Medical Genetics, Osaka Women’s and Children’s Hospital, Izumi 594-1101, Japan
| | - Hirotomo Saitsu
- Department of Biochemistry, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan; (T.O.); (H.S.)
| | - Sachiko Nishina
- National Center for Child Health and Development, Department of Ophthalmology and Laboratory for Visual Science, Tokyo 157-8535, Japan; (N.A.); (S.N.)
| | - Yoshihiro Hotta
- Department of Ophthalmology, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan; (N.T.); (K.H.); (S.N.); (S.A.); (K.T.); (K.K.); (M.S.)
- Correspondence: ; Tel.: +81-53-435-2256
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8
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Kohl S, Baumann B, Dassie F, Mayer AK, Solaki M, Reuter P, Kühlewein L, Wissinger B, Maffei P. Paternal Uniparental Isodisomy of Chromosome 2 in a Patient with CNGA3-Associated Autosomal Recessive Achromatopsia. Int J Mol Sci 2021; 22:7842. [PMID: 34360608 PMCID: PMC8346044 DOI: 10.3390/ijms22157842] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 07/13/2021] [Accepted: 07/21/2021] [Indexed: 01/18/2023] Open
Abstract
Achromatopsia (ACHM) is a rare autosomal recessively inherited retinal disease characterized by congenital photophobia, nystagmus, low visual acuity, and absence of color vision. ACHM is genetically heterogeneous and can be caused by biallelic mutations in the genes CNGA3, CNGB3, GNAT2, PDE6C, PDE6H, or ATF6. We undertook molecular genetic analysis in a single female patient with a clinical diagnosis of ACHM and identified the homozygous variant c.778G>C;p.(D260H) in the CNGA3 gene. While segregation analysis in the father, as expected, identified the CNGA3 variant in a heterozygous state, it could not be displayed in the mother. Microsatellite marker analysis provided evidence that the homozygosity of the CNGA3 variant is due to partial or complete paternal uniparental isodisomy (UPD) of chromosome 2 in the patient. Apart from the ACHM phenotype, the patient was clinically unsuspicious and healthy. This is one of few examples proving UPD as the underlying mechanism for the clinical manifestation of a recessive mutation in a patient with inherited retinal disease. It also highlights the importance of segregation analysis in both parents of a given patient or especially in cases of homozygous recessive mutations, as UPD has significant implications for genetic counseling with a very low recurrence risk assessment in such families.
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Affiliation(s)
- Susanne Kohl
- Centre for Ophthalmology, Institute for Ophthalmic Research, University Tübingen, 72076 Tübingen, Germany; (B.B.); (A.K.M.); (M.S.); (P.R.); (L.K.); (B.W.)
| | - Britta Baumann
- Centre for Ophthalmology, Institute for Ophthalmic Research, University Tübingen, 72076 Tübingen, Germany; (B.B.); (A.K.M.); (M.S.); (P.R.); (L.K.); (B.W.)
| | - Francesca Dassie
- Department of Medicine (DIMED), University of Padua, 35121 Padua, Italy; (F.D.); (P.M.)
| | - Anja K. Mayer
- Centre for Ophthalmology, Institute for Ophthalmic Research, University Tübingen, 72076 Tübingen, Germany; (B.B.); (A.K.M.); (M.S.); (P.R.); (L.K.); (B.W.)
| | - Maria Solaki
- Centre for Ophthalmology, Institute for Ophthalmic Research, University Tübingen, 72076 Tübingen, Germany; (B.B.); (A.K.M.); (M.S.); (P.R.); (L.K.); (B.W.)
| | - Peggy Reuter
- Centre for Ophthalmology, Institute for Ophthalmic Research, University Tübingen, 72076 Tübingen, Germany; (B.B.); (A.K.M.); (M.S.); (P.R.); (L.K.); (B.W.)
| | - Laura Kühlewein
- Centre for Ophthalmology, Institute for Ophthalmic Research, University Tübingen, 72076 Tübingen, Germany; (B.B.); (A.K.M.); (M.S.); (P.R.); (L.K.); (B.W.)
- Centre for Ophthalmology, University Eye Hospital, University Tübingen, 72076 Tübingen, Germany
| | - Bernd Wissinger
- Centre for Ophthalmology, Institute for Ophthalmic Research, University Tübingen, 72076 Tübingen, Germany; (B.B.); (A.K.M.); (M.S.); (P.R.); (L.K.); (B.W.)
| | - Pietro Maffei
- Department of Medicine (DIMED), University of Padua, 35121 Padua, Italy; (F.D.); (P.M.)
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9
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Aoun M, Passerini I, Chiurazzi P, Karali M, De Rienzo I, Sartor G, Murro V, Filimonova N, Seri M, Banfi S. Inherited Retinal Diseases Due to RPE65 Variants: From Genetic Diagnostic Management to Therapy. Int J Mol Sci 2021; 22:7207. [PMID: 34281261 PMCID: PMC8268668 DOI: 10.3390/ijms22137207] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 06/25/2021] [Accepted: 06/29/2021] [Indexed: 12/18/2022] Open
Abstract
Inherited retinal diseases (IRDs) are a heterogeneous group of conditions that include retinitis pigmentosa (RP) and Leber congenital amaurosis (LCA) and early-onset severe retinal dystrophy (EO[S]RD), which differ in severity and age of onset. IRDs are caused by mutations in >250 genes. Variants in the RPE65 gene account for 0.6-6% of RP and 3-16% of LCA/EORD cases. Voretigene neparvovec is a gene therapy approved for the treatment of patients with an autosomal recessive retinal dystrophy due to confirmed biallelic RPE65 variants (RPE65-IRDs). Therefore, the accurate molecular diagnosis of RPE65-IRDs is crucial to identify 'actionable' genotypes-i.e., genotypes that may benefit from the treatment-and is an integral part of patient management. To date, hundreds of RPE65 variants have been identified, some of which are classified as pathogenic or likely pathogenic, while the significance of others is yet to be established. In this review, we provide an overview of the genetic diagnostic workup needed to select patients that could be eligible for voretigene neparvovec treatment. Careful clinical characterization of patients by multidisciplinary teams of experts, combined with the availability of next-generation sequencing approaches, can accelerate patients' access to available therapeutic options.
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Affiliation(s)
- Manar Aoun
- Novartis Farma, Largo Boccioni 1, 21040 Origgio, Italy;
| | - Ilaria Passerini
- Department of Genetic Diagnosis, Careggi Teaching Hospital, 50134 Florence, Italy;
| | - Pietro Chiurazzi
- Istituto di Medicina Genomica, Università Cattolica del Sacro Cuore, 00168 Rome, Italy;
- Fondazione Policlinico Universitario “A. Gemelli” IRCCS, UOC Genetica Medica, 00168 Roma, Italy
| | - Marianthi Karali
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, Università degli Studi della Campania “Luigi Vanvitelli”, 80131 Naples, Italy;
- Telethon Institute of Genetics and Medicine (TIGEM), 80078 Pozzuoli, Italy
| | - Irene De Rienzo
- Department of Ophthalmology, AOU-Careggi, 50234 Florence, Italy;
| | - Giovanna Sartor
- Medical Genetics Unit, IRCCS Azienda Ospedaliero-Universitaria di Bologna, 40138 Bologna, Italy;
| | - Vittoria Murro
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Eye Clinic Careggi Teaching Hospital, 50234 Florence, Italy;
| | | | - Marco Seri
- Medical Genetics Unit, IRCCS Azienda Ospedaliero-Universitaria di Bologna, 40138 Bologna, Italy;
- Department of Surgical and Medical Sciences, University of Bologna, 40138 Bologna, Italy
| | - Sandro Banfi
- Telethon Institute of Genetics and Medicine (TIGEM), 80078 Pozzuoli, Italy
- Medical Genetics, Department of Precision Medicine, University of Campania “Luigi Vanvitelli”, 80138 Naples, Italy
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10
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Motta FL, Filippelli-Silva R, Kitajima JP, Batista DA, Wohler ES, Sobreira NL, Martin RP, Ferraz Sallum JM. Analysis of an NGS retinopathy panel detects chromosome 1 uniparental isodisomy in a patient with RPE65-related leber congenital amaurosis. Ophthalmic Genet 2021; 42:553-560. [PMID: 34157943 DOI: 10.1080/13816810.2021.1938136] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Purpose: This study aims to demonstrate the possibility of detecting segmental uniparental isodisomy (iUPD) using a next-generation sequencing gene panel by reporting a Leber congenital amaurosis (LCA) case caused by a homozygous pathogenic variant in RPE65 (c.1022 T > C:p.Leu341Ser) inherited exclusively from the proband's mother.Methods: Samples from the trio (proband, mother, and father) were sequenced with a next-generation sequencing (NGS) retinopathy gene panel (224 genes) and the VCF file containing all variants was used in order to determine single nucleotide variant (SNV) counts from each sample across all chromosomes.Results: Trio analysis showed that of 81 Chr1 inherited variants 41 were exclusively maternal, including 21 homozygous. The other 40 variants were common to both parents. On remaining autosomal chromosomes (Chr2-22) 645 inherited variants were found, 147 of them were exclusively maternal and 132 exclusively paternal. Based on these NGS data, it was possible to note that the proband's chromosomes 1 are more similar to his mother's chromosome 1 than his father's, suggesting the pathogenic homozygous variant found in this patient was inherited exclusively from the mother due to uniparental maternal isodisomy.Conclusions: This study presents a secondary analysis pipeline to identify responsible variants for a phenotype and the correct inheritance pattern, which is a critical step to the proper and accurate genetic counseling of all family members. In addition, this approach could be used to determine iUPD in different Mendelian disorders if the sequencing panel identifies variants spread throughout the genome.
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Affiliation(s)
- Fabiana Louise Motta
- Department of Ophthalmology, Universidade Federal de São Paulo, Sao Paulo, Brazil
| | | | | | - Denise A Batista
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Elizabeth S Wohler
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins Medicine, Baltimore, Maryland, USA
| | - Nara L Sobreira
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins Medicine, Baltimore, Maryland, USA
| | - Renan Paulo Martin
- Department of Biophysics, Universidade Federal de São Paulo, Sao Paulo, Brazil.,McKusick-Nathans Department of Genetic Medicine, Johns Hopkins Medicine, Baltimore, Maryland, USA
| | - Juliana Maria Ferraz Sallum
- Department of Ophthalmology, Universidade Federal de São Paulo, Sao Paulo, Brazil.,Instituto de Genética Ocular, Sao Paulo, Brazil
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11
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A Homozygous Deletion of Exon 5 of KYNU Resulting from a Maternal Chromosome 2 Isodisomy (UPD2) Causes Catel-Manzke-Syndrome/VCRL Syndrome. Genes (Basel) 2021; 12:genes12060879. [PMID: 34200361 PMCID: PMC8227568 DOI: 10.3390/genes12060879] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 05/28/2021] [Accepted: 06/01/2021] [Indexed: 01/17/2023] Open
Abstract
Vertebral, Cardiac, Renal and Limb Defect Syndrome (VCRL), is a very rare congenital malformation syndrome. Pathogenic variants in HAAO (3-Hydroxyanthranilate 3,4-dioxygenase), NADSYN1 (NAD+ Synthetase-1) and KYNU (Kynureninase) have been identified in a handful of affected individuals. All three genes encode for enzymes essential for the NAD+ de novo synthesis pathway. Using Trio-Exome analysis and CGH array analysis in combination with long range PCR, we have identified a novel homozygous copy number variant (CNV) encompassing exon 5 of KYNU in an individual presenting with overlapping features of VCRL and Catel–Manzke Syndrome. Interestingly, only the mother, not the father carried the small deletion in a heterozygous state. High-resolution SNP array analysis subsequently delineated a maternal isodisomy of chromosome 2 (UPD2). Increased xanthurenic acid excretion in the urine confirmed the genetic diagnosis. Our findings confirm the clinical, genetic and metabolic phenotype of VCRL1, adding a novel functionally tested disease allele. We also describe the first patient with NAD+ deficiency disorder resulting from a UPD. Furthermore, we provide a comprehensive review of the current literature covering the genetic basis and pathomechanisms for VCRL and Catel–Manzke Syndrome, including possible phenotype/genotype correlations as well as genetic causes of hypoplastic left heart syndrome.
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12
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Souzeau E, Dubowsky A, Ruddle JB, Craig JE. Primary congenital glaucoma due to paternal uniparental isodisomy of chromosome 2 and CYP1B1 deletion. Mol Genet Genomic Med 2019; 7:e774. [PMID: 31251480 PMCID: PMC6687653 DOI: 10.1002/mgg3.774] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 04/15/2019] [Accepted: 04/22/2019] [Indexed: 11/24/2022] Open
Abstract
Background CYP1B1 variants and deletions are the most common cause of primary congenital glaucoma (PCG). Methods We investigated an individual with PCG from the Australian and New Zealand Registry of Advanced Glaucoma. We performed sequencing of the CYP1B1 gene, followed by Multiplex Ligation‐dependent Probe Amplification and SNP array. Results We identified a homozygous deletion of the CYP1B1 gene by Multiplex Ligation‐dependent Probe Amplification and confirmed that the father was heterozygous for a CYP1B1 deletion but the mother had normal gene copy number. SNP array identified paternal uniparental isodisomy of the entire chromosome 2. Conclusions This study is the first report of a homozygous CYP1B1 whole gene deletion due to paternal uniparental isodisomy of chromosome 2 as a cause of PCG. These results illustrate the importance of genetic testing in providing appropriate genetic counseling regarding the risks of recurrence.
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Affiliation(s)
- Emmanuelle Souzeau
- Department of Ophthalmology, Flinders University, Flinders Medical Centre, Adelaide, South Australia, Australia
| | - Andrew Dubowsky
- SA Pathology, Flinders Medical Centre, Adelaide, South Australia, Australia
| | - Jonathan B Ruddle
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, University of Melbourne, Melbourne, Victoria, Australia.,Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, Victoria, Australia.,Department of Ophthalmology, Royal Children's Hospital, Melbourne, Victoria, Australia
| | - Jamie E Craig
- Department of Ophthalmology, Flinders University, Flinders Medical Centre, Adelaide, South Australia, Australia
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13
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Souzeau E, Thompson JA, McLaren TL, De Roach JN, Barnett CP, Lamey TM, Craig JE. Maternal uniparental isodisomy of chromosome 6 unmasks a novel variant in TULP1 in a patient with early onset retinal dystrophy. Mol Vis 2018; 24:478-484. [PMID: 30090012 PMCID: PMC6066270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 07/19/2018] [Indexed: 10/26/2022] Open
Abstract
Purpose Inherited retinal dystrophies are a clinically and genetically heterogeneous group of disorders. Molecular diagnosis has proven utility for affected individuals. In this study, we report an individual enrolled in the Australian Inherited Retinal Disease Registry and DNA Bank diagnosed with clinical features overlapping between Leber congenital amaurosis and retinitis pigmentosa. Methods DNA from the proband was sequenced using a gene panel for inherited retinal disorders, and a single nucleotide polymorphism (SNP) array was conducted to detect the presence of deletions and uniparental disomy. Results We identified a novel homozygous variant (c.524dupC, p.(Pro176ThrfsTer7)) in TULP1 resulting from maternal uniparental isodisomy of chromosome 6. The patient had clinical features consistent with biallelic pathogenic variants in TULP1, including congenital nystagmus, night blindness, non-recordable electroretinogram, mild myopia, and mild peripheral pigmentary changes in the fundus. Conclusions This is the first report of uniparental disomy 6 and a homozygous variant in TULP1 associated with a rod-cone dystrophy. Molecular diagnosis of inherited retinal dystrophies is essential to inform the mode of transmission and clinical management, and to identify potential candidates for future gene-specific therapies.
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Affiliation(s)
- Emmanuelle Souzeau
- Department of Ophthalmology, Flinders University, Flinders Medical Centre, Adelaide, Australia
| | - Jennifer A. Thompson
- Australian Inherited Retinal Disease Registry & DNA Bank, Department of Medical Technology & Physics, Sir Charles Gairdner Hospital, Perth, Australia
| | - Terri L. McLaren
- Australian Inherited Retinal Disease Registry & DNA Bank, Department of Medical Technology & Physics, Sir Charles Gairdner Hospital, Perth, Australia
| | - John N. De Roach
- Australian Inherited Retinal Disease Registry & DNA Bank, Department of Medical Technology & Physics, Sir Charles Gairdner Hospital, Perth, Australia,Centre for Ophthalmology & Visual Science, The University of Western Australia, Perth, Australia
| | - Christopher P. Barnett
- Paediatric and Reproductive Genetics unit, Women’s and Children’s Hospital, Adelaide, Australia
| | - Tina M. Lamey
- Australian Inherited Retinal Disease Registry & DNA Bank, Department of Medical Technology & Physics, Sir Charles Gairdner Hospital, Perth, Australia,Centre for Ophthalmology & Visual Science, The University of Western Australia, Perth, Australia
| | - Jamie E. Craig
- Department of Ophthalmology, Flinders University, Flinders Medical Centre, Adelaide, Australia
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14
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Audo I, Mohand-Said S, Boulanger-Scemama E, Zanlonghi X, Condroyer C, Démontant V, Boyard F, Antonio A, Méjécase C, El Shamieh S, Sahel JA, Zeitz C. MERTK
mutation update in inherited retinal diseases. Hum Mutat 2018; 39:887-913. [DOI: 10.1002/humu.23431] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 03/22/2018] [Accepted: 03/29/2018] [Indexed: 11/08/2022]
Affiliation(s)
- Isabelle Audo
- Sorbonne Université; INSERM; CNRS; Institut de la Vision; Paris France
- CHNO des Quinze-Vingts; DHU Sight Restore; INSERM-DGOS CIC1423 Paris France
- University College London Institute of Ophthalmology; London UK
| | - Saddek Mohand-Said
- Sorbonne Université; INSERM; CNRS; Institut de la Vision; Paris France
- CHNO des Quinze-Vingts; DHU Sight Restore; INSERM-DGOS CIC1423 Paris France
| | - Elise Boulanger-Scemama
- Sorbonne Université; INSERM; CNRS; Institut de la Vision; Paris France
- Fondation Ophtalmologique Adolphe de Rothschild; Paris France
| | | | | | - Vanessa Démontant
- Sorbonne Université; INSERM; CNRS; Institut de la Vision; Paris France
| | - Fiona Boyard
- Sorbonne Université; INSERM; CNRS; Institut de la Vision; Paris France
| | - Aline Antonio
- Sorbonne Université; INSERM; CNRS; Institut de la Vision; Paris France
| | - Cécile Méjécase
- Sorbonne Université; INSERM; CNRS; Institut de la Vision; Paris France
| | - Said El Shamieh
- Sorbonne Université; INSERM; CNRS; Institut de la Vision; Paris France
- Department of Medical Laboratory Technology; Faculty of Health Sciences; Beirut Arab University; Beirut Lebanon
| | - José-Alain Sahel
- Sorbonne Université; INSERM; CNRS; Institut de la Vision; Paris France
- CHNO des Quinze-Vingts; DHU Sight Restore; INSERM-DGOS CIC1423 Paris France
- University College London Institute of Ophthalmology; London UK
- Fondation Ophtalmologique Adolphe de Rothschild; Paris France
- Académie des Sciences-Institut de France; Paris France. Department of Ophthalmology; University of Pittsburgh Medical School; Pittsburgh Pennsylvania
| | - Christina Zeitz
- Sorbonne Université; INSERM; CNRS; Institut de la Vision; Paris France
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15
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Inana G, Murat C, An W, Yao X, Harris IR, Cao J. RPE phagocytic function declines in age-related macular degeneration and is rescued by human umbilical tissue derived cells. J Transl Med 2018. [PMID: 29534722 PMCID: PMC5851074 DOI: 10.1186/s12967-018-1434-6] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Background Age-related macular degeneration (AMD) is a leading cause of blindness among the elderly characterized by retinal pigment epithelium (RPE) degeneration with accumulation of abnormal intracellular deposits (lipofuscin) and photoreceptor death. RPE is vital for the retina and integrity of photoreceptors through its phagocytic function which is closely linked to formation of lipofuscin through daily phagocytosis of discarded photoreceptor outer segments (POS). Although phagocytosis has been implicated in AMD, it has not been directly shown to be altered in AMD. RPE phagocytic defect was previously shown to be rescued by subretinal injection of human umbilical tissue derived cells (hUTC) in a rodent model of retinal degeneration (RCS rat) through receptor tyrosine kinase (RTK) ligands and bridge molecules. Here, we examined RPE phagocytic function directly in the RPE from AMD patients and the ability and mechanisms of hUTC to affect phagocytosis in the human RPE. Methods Human RPE was isolated from the post-mortem eyes of normal and AMD-affected subjects and cultured. RPE phagocytic function was measured in vitro using isolated POS. The effects of hUTC conditioned media, recombinant RTK ligands brain-derived neurotrophic factor (BDNF), hepatocyte growth factor (HGF), and glial cell-derived neurotrophic factor (GDNF), as well as bridge molecules milk-fat-globule-EGF-factor 8 (MFG-E8), thrombospondin (TSP)-1, and TSP-2 on phagocytosis were also examined in phagocytosis assays using isolated POS. RNA was isolated from normal and AMD RPE treated with hUTC conditioned media and subjected to transcriptome profiling by RNA-Seq and computational analyses. Results RPE phagocytosis, while showing a moderate decline with age, was significantly reduced in AMD RPE, more than expected for age. hUTC conditioned media stimulated phagocytosis in the normal human RPE and significantly rescued the phagocytic dysfunction in the AMD RPE. RTK ligands and bridge molecules duplicated the rescue effect. Moreover, multiple molecular pathways involving phagocytosis, apoptosis, oxidative stress, inflammation, immune activation, and cholesterol transport were affected by hUTC in the RPE. Conclusions We demonstrated for the first time RPE phagocytic dysfunction in AMD, highlighting its likely importance in AMD, and the ability of hUTC to correct this dysfunction, providing insights into the therapeutic potential of hUTC for AMD. Electronic supplementary material The online version of this article (10.1186/s12967-018-1434-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- George Inana
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami School of Medicine, 1638 N.W. 10th Avenue, Miami, FL, 33136, USA.
| | - Christopher Murat
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami School of Medicine, 1638 N.W. 10th Avenue, Miami, FL, 33136, USA
| | - Weijun An
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami School of Medicine, 1638 N.W. 10th Avenue, Miami, FL, 33136, USA
| | - Xiang Yao
- Janssen Research & Development, LLC, San Diego, CA, 92121, USA
| | - Ian R Harris
- Janssen Research & Development, LLC, Spring House, PA, 19477, USA
| | - Jing Cao
- Janssen Research & Development, LLC, Spring House, PA, 19477, USA.
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16
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Kim WJ, Park HJ, Choi YJ, Kwon EY, Kim BM, Lee JH, Chang JH, Lee Kang J, Choi JH. Association between Genetic Variations of MERTK and Chronic Obstructive Pulmonary Disease in Koreans. J Korean Med Sci 2018; 33:e56. [PMID: 29359540 PMCID: PMC5785628 DOI: 10.3346/jkms.2018.33.e56] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 12/12/2017] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND Chronic obstructive pulmonary disease (COPD) is a debilitating lung disease. To date, a large number of clinical studies have been conducted to investigate the association between genetic variations and COPD. However, little is known regarding the genetic susceptibility of Koreans to this disease. MER receptor tyrosine kinase (MERTK) plays important roles in the inhibition of inflammation and in the clearance of apoptotic cells. Here, we investigated the association between genetic variations in MERTK and the development of COPD in Koreans. METHODS We conducted genetic analysis of MERTK using genomic DNA samples from 87 patients with COPD and 88 healthy controls and compared the frequency of each variation or haplotype between the patient and control groups. Subsequently, the effect of each variation was evaluated using in vitro assays. RESULTS Ten variations were identified in this study, four of them for the first time. In addition, we found that the frequency of each variation or haplotype was comparable between the patient and control groups. However, we observed that the frequency for the wild-type haplotype was higher in the control group, compared to that in the group of patients with COPD, in the subgroup analysis of current smokers, although the difference was not statistically significant (P = 0.080). In in vitro assays, we observed that none of the variations affected the activity of the promoter or the expression of MERTK. CONCLUSION Our findings indicate that the susceptibility to COPD is not related to the genetic variations or haplotypes of MERTK in Koreans.
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Affiliation(s)
- Woo Jin Kim
- Department of Internal Medicine and Environmental Health Center, Kangwon National University, Chuncheon, Korea
| | - Hyo Jin Park
- Department of Pharmacology, Tissue Injury Defense Research Center, College of Medicine, Ewha Womans University, Seoul, Korea
| | - Yang Ji Choi
- Department of Pharmacology, Tissue Injury Defense Research Center, College of Medicine, Ewha Womans University, Seoul, Korea
| | - Eun Young Kwon
- Department of Pharmacology, Tissue Injury Defense Research Center, College of Medicine, Ewha Womans University, Seoul, Korea
| | - Bo Min Kim
- Department of Pharmacology, Tissue Injury Defense Research Center, College of Medicine, Ewha Womans University, Seoul, Korea
| | - Jin Hwa Lee
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, College of Medicine, Ewha Womans University, Seoul, Korea
| | - Jung Hyun Chang
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, College of Medicine, Ewha Womans University, Seoul, Korea
| | - Jihee Lee Kang
- Department of Physiology, Tissue Injury Defense Research Center, College of Medicine, Ewha Womans University, Seoul, Korea
| | - Ji Ha Choi
- Department of Pharmacology, Tissue Injury Defense Research Center, College of Medicine, Ewha Womans University, Seoul, Korea.
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17
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LaVail MM, Nishikawa S, Steinberg RH, Naash MI, Duncan JL, Trautmann N, Matthes MT, Yasumura D, Lau-Villacorta C, Chen J, Peterson WM, Yang H, Flannery JG. Phenotypic characterization of P23H and S334ter rhodopsin transgenic rat models of inherited retinal degeneration. Exp Eye Res 2018; 167:56-90. [PMID: 29122605 PMCID: PMC5811379 DOI: 10.1016/j.exer.2017.10.023] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 10/25/2017] [Accepted: 10/31/2017] [Indexed: 02/07/2023]
Abstract
We produced 8 lines of transgenic (Tg) rats expressing one of two different rhodopsin mutations in albino Sprague-Dawley (SD) rats. Three lines were generated with a proline to histidine substitution at codon 23 (P23H), the most common autosomal dominant form of retinitis pigmentosa in the United States. Five lines were generated with a termination codon at position 334 (S334ter), resulting in a C-terminal truncated opsin protein lacking the last 15 amino acid residues and containing all of the phosphorylation sites involved in rhodopsin deactivation, as well as the terminal QVAPA residues important for rhodopsin deactivation and trafficking. The rates of photoreceptor (PR) degeneration in these models vary in proportion to the ratio of mutant to wild-type rhodopsin. The models have been widely studied, but many aspects of their phenotypes have not been described. Here we present a comprehensive study of the 8 Tg lines, including the time course of PR degeneration from the onset to one year of age, retinal structure by light and electron microscopy (EM), hemispheric asymmetry and gradients of rod and cone degeneration, rhodopsin content, gene dosage effect, rapid activation and invasion of the outer retina by presumptive microglia, rod outer segment disc shedding and phagocytosis by the retinal pigmented epithelium (RPE), and retinal function by the electroretinogram (ERG). The biphasic nature of PR cell death was noted, as was the lack of an injury-induced protective response in the rat models. EM analysis revealed the accumulation of submicron vesicular structures in the interphotoreceptor space during the peak period of PR outer segment degeneration in the S334ter lines. This is likely due to the elimination of the trafficking consensus domain as seen before as with other rhodopsin mutants lacking the C-terminal QVAPA. The 8 rhodopsin Tg lines have been, and will continue to be, extremely useful models for the experimental study of inherited retinal degenerations.
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Affiliation(s)
- Matthew M LaVail
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA.
| | - Shimpei Nishikawa
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA.
| | - Roy H Steinberg
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA
| | - Muna I Naash
- Department of Biomedical Engineering, University of Houston, 3517 Cullen Blvd., Room 2011, Houston, TX 77204-5060, USA.
| | - Jacque L Duncan
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA.
| | - Nikolaus Trautmann
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA.
| | - Michael T Matthes
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA.
| | - Douglas Yasumura
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA
| | - Cathy Lau-Villacorta
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA.
| | - Jeannie Chen
- Zilka Neurogenetic Institute, USC Keck School of Medicine, Los Angeles, CA 90089-2821, USA.
| | - Ward M Peterson
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA.
| | - Haidong Yang
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA.
| | - John G Flannery
- School of Optometry, UC Berkeley, Berkeley, CA 94720-2020, USA.
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18
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Murase H, Tsuruma K, Kuse Y, Shimazawa M, Hara H. Progranulin increases phagocytosis by retinal pigment epithelial cells in culture. J Neurosci Res 2017; 95:2500-2510. [PMID: 28509387 DOI: 10.1002/jnr.24081] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Revised: 03/28/2017] [Accepted: 04/18/2017] [Indexed: 11/07/2022]
Abstract
Retinal pigment epithelium (RPE) cells take part in retinal preservation, such as phagocytizing the shed photoreceptor outer segments (POS), every day. The incomplete phagocytic function accelerates RPE degeneration and formation of the toxic by-product lipofuscin. Excessive lipofuscin accumulation is characteristic of various blinding diseases in the human eye. Progranulin is a cysteine-rich protein that has multiple biological activities, and it has a high presence in the retina. Progranulin has been recognized to be involved in macrophage phagocytosis in the brain. The purpose of this study is to determine whether progranulin influences phagocytosis by RPE cells. All experiments were performed on primary human RPE (hRPE) cells in culture. pHrodo was used to label the isolated porcine POS, and quantification of pHrodo fluorescence was used to determine the degree of phagocytosis. Western blotting and immunohistochemistry of key proteins involved in phagocytosis were used to clarify the mechanism of progranulin. Progranulin increased RPE phagocytosis in hydrogen peroxide-treated and nontreated RPE cells. The phosphorylated form of Mer tyrosine kinase, which is important for POS internalization, was significantly increased in the progranulin-exposed cells. This increase was attenuated by SU11274, an inhibitor of hepatic growth factor receptor. Under the oxidative stress condition, exposure to progranulin led to an approximately twofold increase in integrin alpha-v, which is associated with the first step in recognition of POS by RPE cells. These results suggest that progranulin could be an effective stimulator for RPE phagocytosis and could repair RPE function. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Hiromi Murase
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi, Gifu, 501-1196, Japan
| | - Kazuhiro Tsuruma
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi, Gifu, 501-1196, Japan
| | - Yoshiki Kuse
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi, Gifu, 501-1196, Japan
| | - Masamitsu Shimazawa
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi, Gifu, 501-1196, Japan
| | - Hideaki Hara
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi, Gifu, 501-1196, Japan
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19
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Unravelling the genetic basis of simplex Retinitis Pigmentosa cases. Sci Rep 2017; 7:41937. [PMID: 28157192 PMCID: PMC5291209 DOI: 10.1038/srep41937] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 01/04/2017] [Indexed: 12/20/2022] Open
Abstract
Retinitis Pigmentosa (RP) is the most common form of inherited retinal dystrophy (IRD) characterized ultimately by photoreceptors degeneration. Exhibiting great clinical and genetic heterogeneity, RP can be inherited as an autosomal dominant (ad), autosomal recessive (ar) and X-linked (xl) disorder. Although the relative prevalence of each form varies somewhat between populations, a major proportion (41% in Spain) of patients represent simplex cases (sRP) in which the mode of inheritance is unknown. Molecular genetic diagnostic is crucial, but also challenging, for sRP patients because any of the 81 RP genes identified to date may be causative. Herein, we report the use of a customized targeted gene panel consisting of 68 IRD genes for the molecular characterization of 106 sRP cases. The diagnostic rate was 62.26% (66 of 106) with a proportion of clinical refinements of 30.3%, demonstrating the high efficiency of this genomic approach even for clinically ambiguous cases. The high number of patients diagnosed here has allowed us to study in detail the genetic basis of the sRP. The solved sRP cohort is composed of 62.1% of arRP cases, 24.2% of adRP and 13.6% of xlRP, which implies consequences for counselling of patients and families.
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20
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Bens S, Kolarova J, Beygo J, Buiting K, Caliebe A, Eggermann T, Gillessen-Kaesbach G, Prawitt D, Thiele-Schmitz S, Begemann M, Enklaar T, Gutwein J, Haake A, Paul U, Richter J, Soellner L, Vater I, Monk D, Horsthemke B, Ammerpohl O, Siebert R. Phenotypic spectrum and extent of DNA methylation defects associated with multilocus imprinting disturbances. Epigenomics 2016; 8:801-16. [PMID: 27323310 DOI: 10.2217/epi-2016-0007] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
AIM To characterize the genotypic and phenotypic extent of multilocus imprinting disturbances (MLID). MATERIALS & METHODS We analyzed 37 patients with imprinting disorders (explorative cohort) for DNA methylation changes using the Infinium HumanMethylation450 BeadChip. For validation, three independent cohorts with imprinting disorders or cardinal features thereof were analyzed (84 patients with imprinting disorders, 52 with growth disorder, 81 with developmental delay). RESULTS In the explorative cohort 21 individuals showed array-based MLID with each one displaying an Angelman or Temple syndrome phenotype, respectively. Epimutations in ZDBF2 and FAM50B were associated with severe MLID regarding number of affected regions. By targeted analysis we identified methylation changes of ZDBF2 and FAM50B also in the three validation cohorts. CONCLUSION We corroborate epimutations in ZDBF2 and FAM50B as frequent changes in MLID whereas these rarely occur in other patients with cardinal features of imprinting disorders. Moreover, we show cell lineage specific differences in the genomic extent of FAM50B epimutation.
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Affiliation(s)
- Susanne Bens
- Institute of Human Genetics, Christian-Albrechts-University Kiel & University Hospital Schleswig-Holstein, Campus Kiel, D 24105 Kiel, Germany
| | - Julia Kolarova
- Institute of Human Genetics, Christian-Albrechts-University Kiel & University Hospital Schleswig-Holstein, Campus Kiel, D 24105 Kiel, Germany
| | - Jasmin Beygo
- Institut für Humangenetik, Universitätsklinikum Essen, Universität Duisburg-Essen, D 45122 Essen, Germany
| | - Karin Buiting
- Institut für Humangenetik, Universitätsklinikum Essen, Universität Duisburg-Essen, D 45122 Essen, Germany
| | - Almuth Caliebe
- Institute of Human Genetics, Christian-Albrechts-University Kiel & University Hospital Schleswig-Holstein, Campus Kiel, D 24105 Kiel, Germany
| | - Thomas Eggermann
- Institute of Human Genetics, University Hospital Aachen, D 52074 Aachen, Germany
| | | | - Dirk Prawitt
- Section of Molecular Pediatrics University Medical Centre of the Johannes Gutenberg-University Mainz, D 55131 Mainz, Germany
| | - Susanne Thiele-Schmitz
- Division of Experimental Paediatric Endocrinology & Diabetes, Department of Paediatrics, University of Lübeck, D 23562 Lübeck, Germany
| | - Matthias Begemann
- Institute of Human Genetics, University Hospital Aachen, D 52074 Aachen, Germany
| | - Thorsten Enklaar
- Section of Molecular Pediatrics University Medical Centre of the Johannes Gutenberg-University Mainz, D 55131 Mainz, Germany
| | - Jana Gutwein
- Institute of Human Genetics, Christian-Albrechts-University Kiel & University Hospital Schleswig-Holstein, Campus Kiel, D 24105 Kiel, Germany
| | - Andrea Haake
- Institute of Human Genetics, Christian-Albrechts-University Kiel & University Hospital Schleswig-Holstein, Campus Kiel, D 24105 Kiel, Germany
| | - Ulrike Paul
- Institute of Human Genetics, Christian-Albrechts-University Kiel & University Hospital Schleswig-Holstein, Campus Kiel, D 24105 Kiel, Germany
| | - Julia Richter
- Institute of Human Genetics, Christian-Albrechts-University Kiel & University Hospital Schleswig-Holstein, Campus Kiel, D 24105 Kiel, Germany
| | - Lukas Soellner
- Institute of Human Genetics, University Hospital Aachen, D 52074 Aachen, Germany
| | - Inga Vater
- Institute of Human Genetics, Christian-Albrechts-University Kiel & University Hospital Schleswig-Holstein, Campus Kiel, D 24105 Kiel, Germany
| | - David Monk
- Institut d'Investigació Biomedica de Bellvitge (IDIBELL), Cancer Epigenetic & Biology Program (PEBC), Catalan Institute of Oncology, Hospital Duran i Reynals Barcelona, Barcelona, ES 08907, Spain
| | - Bernhard Horsthemke
- Institut für Humangenetik, Universitätsklinikum Essen, Universität Duisburg-Essen, D 45122 Essen, Germany
| | - Ole Ammerpohl
- Institute of Human Genetics, Christian-Albrechts-University Kiel & University Hospital Schleswig-Holstein, Campus Kiel, D 24105 Kiel, Germany
| | - Reiner Siebert
- Institute of Human Genetics, Christian-Albrechts-University Kiel & University Hospital Schleswig-Holstein, Campus Kiel, D 24105 Kiel, Germany
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21
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Gene Therapy for MERTK-Associated Retinal Degenerations. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 854:487-93. [PMID: 26427450 DOI: 10.1007/978-3-319-17121-0_65] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
MERTK-associated retinal degenerations are thought to have defects in phagocytosis of shed outer segment membranes by the retinal pigment epithelium (RPE), as do the rodent models of these diseases. We have subretinally injected an RPE-specific AAV2 vector, AAV2-VMD2-hMERTK, to determine whether this would provide long-term photoreceptor rescue in the RCS rat, which it did for up to 6.5 months, the longest time point examined. Moreover, we found phagosomes in the RPE in the rescued regions of RCS retinas soon after the onset of light. The same vector also had a major protective effect in Mertk-null mice, with a concomitant increase in ERG response amplitudes in the vector-injected eyes. These findings suggest that planned clinical trials with this vector will have a favorable outcome.
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22
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Astuti GDN, Bertelsen M, Preising MN, Ajmal M, Lorenz B, Faradz SMH, Qamar R, Collin RWJ, Rosenberg T, Cremers FPM. Comprehensive genotyping reveals RPE65 as the most frequently mutated gene in Leber congenital amaurosis in Denmark. Eur J Hum Genet 2015; 24:1071-9. [PMID: 26626312 DOI: 10.1038/ejhg.2015.241] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Revised: 10/09/2015] [Accepted: 10/14/2015] [Indexed: 12/31/2022] Open
Abstract
Leber congenital amaurosis (LCA) represents the most severe form of inherited retinal dystrophies with an onset during the first year of life. Currently, 21 genes are known to be associated with LCA and recurrent mutations have been observed in AIPL1, CEP290, CRB1 and GUCY2D. In addition, sequence analysis of LRAT and RPE65 may be important in view of treatments that are emerging for patients carrying variants in these genes. Screening of the aforementioned variants and genes was performed in 64 Danish LCA probands. Upon the identification of heterozygous variants, Sanger sequencing was performed of the relevant genes to identify the second allele. In combination with prior arrayed primer extension analysis, this led to the identification of two variants in 42 of 86 cases (49%). Remarkably, biallelic RPE65 variants were identified in 16% of the cases, and one novel variant, p.(D110G), was found in seven RPE65 alleles. We also collected all previously published RPE65 variants, identified in 914 alleles of 539 patients with LCA or early-onset retinitis pigmentosa, and deposited them in the RPE65 Leiden Open Variation Database (LOVD). The in silico pathogenicity assessment of the missense and noncanonical splice site variants, as well as an analysis of their frequency in ~60 000 control individuals, rendered 864 of the alleles to affect function or probably affect function. This comprehensive database can now be used to select patients eligible for gene augmentation or retinoid supplementation therapies.
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Affiliation(s)
- Galuh D N Astuti
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands.,Division of Human Genetics, Center for Biomedical Research (CEBIOR), Faculty of Medicine, Diponegoro University, Semarang, Indonesia
| | - Mette Bertelsen
- Kennedy Center Eye Clinic, Glostrup Hospital, Glostrup, Denmark.,Department of Ophthalmology, Glostrup Hospital, Glostrup, Denmark.,Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Markus N Preising
- Department of Ophthalmology, Justus-Liebig University Giessen, Giessen, Germany
| | - Muhammad Ajmal
- Department of Biosciences, Faculty of Science, COMSATS Institute of Information Technology, Islamabad, Pakistan
| | - Birgit Lorenz
- Department of Ophthalmology, Justus-Liebig University Giessen, Giessen, Germany
| | - Sultana M H Faradz
- Division of Human Genetics, Center for Biomedical Research (CEBIOR), Faculty of Medicine, Diponegoro University, Semarang, Indonesia
| | - Raheel Qamar
- Department of Biosciences, Faculty of Science, COMSATS Institute of Information Technology, Islamabad, Pakistan.,Al-Nafees Medical College and Hospital, Isra University, Islamabad, Pakistan
| | - Rob W J Collin
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Thomas Rosenberg
- Kennedy Center Eye Clinic, Glostrup Hospital, Glostrup, Denmark.,Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Frans P M Cremers
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Biosciences, Faculty of Science, COMSATS Institute of Information Technology, Islamabad, Pakistan
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23
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Cao J, Murat C, An W, Yao X, Lee J, Santulli-Marotto S, Harris IR, Inana G. Human umbilical tissue-derived cells rescue retinal pigment epithelium dysfunction in retinal degeneration. Stem Cells 2015; 34:367-79. [PMID: 26523756 DOI: 10.1002/stem.2239] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 09/29/2015] [Indexed: 12/20/2022]
Abstract
Retinal pigment epithelium (RPE) cells perform many functions crucial for retinal preservation and vision. RPE cell dysfunction results in various retinal degenerative diseases, such as retinitis pigmentosa and age-related macular degeneration (AMD). Currently, there are no effective treatments for retinal degeneration except for a small percentage of individuals with exudative AMD. Cell therapies targeting RPE cells are being developed in the clinic for the treatment of retinal degeneration. Subretinal injection of human umbilical tissue-derived cells (hUTC) in the Royal College of Surgeons (RCS) rat model of retinal degeneration was shown to preserve photoreceptors and visual function. However, the precise mechanism remains unclear. Here, we demonstrate that hUTC rescue phagocytic dysfunction in RCS RPE cells in vitro. hUTC secrete receptor tyrosine kinase (RTK) ligands brain-derived neurotrophic factor (BDNF), hepatocyte growth factor (HGF), and glial cell-derived neurotrophic factor (GDNF), as well as opsonizing bridge molecules milk-fat-globule-epidermal growth factor 8 (MFG-E8), growth arrest-specific 6 (Gas6), thrombospondin (TSP)-1, and TSP-2. The effect of hUTC on phagocytosis rescue in vitro is mimicked by recombinant human proteins of these factors and is abolished by siRNA-targeted gene silencing in hUTC. The bridge molecules secreted from hUTC bind to the photoreceptor outer segments and facilitate their ingestion by the RPE. This study elucidates novel cellular mechanisms for the repair of RPE function in retinal degeneration through RTK ligands and bridge molecules, and demonstrates the potential of using hUTC for the treatment of retinal degenerative diseases.
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Affiliation(s)
- Jing Cao
- Janssen Research and Development, LLC, Spring House, Pennsylvania, USA
| | - Christopher Murat
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Weijun An
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Xiang Yao
- Janssen Research and Development, LLC, San Diego, California, USA
| | - John Lee
- Janssen Research and Development, LLC, Spring House, Pennsylvania, USA
| | | | - Ian R Harris
- Janssen Research and Development, LLC, Spring House, Pennsylvania, USA
| | - George Inana
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA
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24
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Wen Y, Birch DG. Outer Segment Thickness Predicts Visual Field Response to QLT091001 in Patients with RPE65 or LRAT Mutations. Transl Vis Sci Technol 2015; 4:8. [PMID: 26448901 DOI: 10.1167/tvst.4.5.8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 08/17/2015] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To determine whether the degree of change in Goldmann visual fields (GVFs) following oral administration of QLT091001 was related to baseline measures of retinal structure. METHODS Oral QLT091001 was administered once daily for 7 days in all study patients. Comprehensive ophthalmic testing, including spectral-domain optical coherence tomography (SD-OCT), was conducted in 14 patients with Leber congenital amaurosis (LCA) and 18 patients with retinitis pigmentosa (RP) at seven international sites. Average thickness of the outer segment (OS) layer was calculated over central 20°. Both eyes of each subject were evaluated separately. RESULTS Nineteen of 28 eyes (68%) with LCA and 13 of 36 eyes (36%) with RP responded to QLT091001. Among these responders, the average baseline thickness of the OS layer (central 20°) was 13.5 μm in the LCA cohort and 11.7 μm in the RP cohort. Nonresponders had average baseline OS thickness of less than 4.6 μm in both cohorts. The OS thickness in the central 20° was significantly shorter in nonresponders than responders in the LCA cohort (P = 0.01, t-test) and in the RP cohort (P = 0.02, Wilcoxon rank sum test). The OS thickness in the central 20° did not change significantly from baseline during the first 2 months (P = 0.09, t-test, paired). CONCLUSIONS The present findings suggest that there is a close parallel between the thickness of the photoreceptor layer and the potential for functional improvement in these patients. TRANSLATIONAL RELEVANCE SD-OCT thickness in the central retina may be useful for predicting the visual field response in the peripheral retina to QLT091001. (https://clinicaltrials.gov/ct2/show/NCT01014052 number, NCT01014052).
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Affiliation(s)
- Yuquan Wen
- Retina Foundation of the Southwest, Dallas, TX, USA
| | - David G Birch
- Retina Foundation of the Southwest, Dallas, TX, USA ; Ophthalmology, University of Texas Southwestern Medical Center, Dallas, TX, USA
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25
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Tang Y, Lu Q, Wei Y, Han L, Ji R, Li Q, Lu Q. Mertk deficiency alters expression of micrornas in the retinal pigment epithelium cells. Metab Brain Dis 2015; 30:943-50. [PMID: 25604732 PMCID: PMC4492868 DOI: 10.1007/s11011-015-9653-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 01/13/2015] [Indexed: 10/24/2022]
Abstract
Phagocytic clearance of the spent photoreceptor outer segments (OS) by RPE cells is regulated by circadian rhythm cycle and is essential for photoreceptor integrity and function. Mertk regulates RPE phagocytosis and a deficiency in Mertk causes photoreceptor degeneration and visual loss. This study aimed to investigate Mertk regulation of the microRNAs (miRNA), potentially regulating expression of their target genes, which affect phagocytosis. The differentially expressed miRNAs were identified using miRCURY(TM) microRNA Arrays from total RNA isolated at 0900 h and 1900 h from the mechanically dissociated RPE sheets of the WT and Mertk (-/-) mice, which were housed in a 12-h light-dark cycle with the lighting onset at 0700 h (7:00am). Validation of the differentially expressed miRNAs and assessment of the putative miRNA target gene expression were performed by real-time PCR. Among the differentially expressed miRNAs in the Mertk (-/-) RPE, seven miRNAs were up-regulated and 13 were down-regulated in the morning groups. Similarly, 24 miRNAs were found to be up-regulated and 13 were down-regulated in the evening groups. To search for those that may participate in regulating expression of cytoskeletal proteins, we examined the predicted target genes that might participate in phagocytosis were examined by real-time PCR. Of nine potential altered targets, four deregulated genes were myosin subunits. Notably, multiple members of the 21 up-regulated miRNAs can theoretically recognize these down-regulated mRNAs, particularly MyH14 and Myl3. This study shows that loss of Mertk alters miRNA expression, which in turn affects expression of the downstream target genes, potentially affecting phagocytosis.
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Affiliation(s)
- Yong Tang
- Faculty of Basic Medical Science, Capital Medical
University, Beijing 100069, China
| | - Qingjun Lu
- Faculty of Basic Medical Science, Capital Medical
University, Beijing 100069, China
- Beijing Institute of Ophthalmology, Beijing Tong-Ren
Hospital, Capital Medical University, Beijing 100069, China
- Beijing Tong-Ren Eye Center, Beijing Tong-Ren Hospital,
Capital Medical University, Beijing 100069, China
| | - Yunrong Wei
- Faculty of Basic Medical Science, Capital Medical
University, Beijing 100069, China
| | - Lixia Han
- Departments of Ophthalmology and Visual Sciences, and
Biochemistry and Molecular Biology; University of Louisville, KY, 40202, USA
| | - Rui Ji
- Departments of Ophthalmology and Visual Sciences, and
Biochemistry and Molecular Biology; University of Louisville, KY, 40202, USA
| | - Qiutang Li
- Departments of Ophthalmology and Visual Sciences, and
Biochemistry and Molecular Biology; University of Louisville, KY, 40202, USA
| | - Qingxian Lu
- Faculty of Basic Medical Science, Capital Medical
University, Beijing 100069, China
- Departments of Ophthalmology and Visual Sciences, and
Biochemistry and Molecular Biology; University of Louisville, KY, 40202, USA
- Address correspondence to: Qingxian Lu,
University of Louisville School of Medicine, 301 E. Muhammad Ali Blvd.,
Louisville, KY 40202, Phone: 1-(502)-852-4768, Fax: 1-(502)-852-6909,
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26
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Ahonen SJ, Arumilli M, Seppälä E, Hakosalo O, Kaukonen MK, Komáromy AM, Lohi H. Increased expression of MERTK is associated with a unique form of canine retinopathy. PLoS One 2014; 9:e114552. [PMID: 25517981 PMCID: PMC4269413 DOI: 10.1371/journal.pone.0114552] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 11/10/2014] [Indexed: 01/25/2023] Open
Abstract
Progressive retinal degenerations are among the most common causes of blindness both in human and in dogs. Canine progressive retinal atrophy (PRA) resembles human retinitis pigmentosa (RP) and is typically characterized by a progressive loss of rod photoreceptors followed by a loss of cone function. The disease gradually progress from the loss of night and day vision to a complete blindness. We have recently described a unique form of retinopathy characterized by the multifocal gray/brown discoloration and thinning of the retina in the Swedish Vallhund (SV) breed. We aimed to identify the genetic cause by performing a genome wide association analysis in a cohort of 18 affected and 10 healthy control dogs using Illumina's canine 22k SNP array. We mapped the disease to canine chromosome 17 (p = 7.7×10−5) and found a 6.1 Mb shared homozygous region in the affected dogs. A combined analysis of the GWAS and replication data with additional 60 dogs confirmed the association (p = 4.3×10−8, OR = 11.2 for homozygosity). A targeted resequencing of the entire associated region in four cases and four controls with opposite risk haplotypes identified several variants in the coding region of functional candidate genes, such as a known retinopathy gene, MERTK. However, none of the identified coding variants followed a compelling case- or breed-specific segregation pattern. The expression analyses of four candidate genes in the region, MERTK, NPHP1, ANAPC1 and KRCC1, revealed specific upregulation of MERTK in the retina of the affected dogs. Collectively, these results indicate that the retinopathy is associated with overexpression of MERTK, however further investigation is needed to discover the regulatory mutation for the better understanding of the disease pathogenesis. Our study establishes a novel gain-of-function model for the MERTK biology and provides a therapy model for retinopathy MERTK inhibitors. Meanwhile, a marker-based genetic counseling can be developed to revise breeding programs.
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Affiliation(s)
- Saija J. Ahonen
- Department of Veterinary Biosciences and Research Programs Unit, Molecular Neurology, University of Helsinki, Helsinki, Finland
- The Folkhälsan Institute of Genetics, Helsinki, Finland
| | - Meharji Arumilli
- Department of Veterinary Biosciences and Research Programs Unit, Molecular Neurology, University of Helsinki, Helsinki, Finland
- The Folkhälsan Institute of Genetics, Helsinki, Finland
| | - Eija Seppälä
- Department of Veterinary Biosciences and Research Programs Unit, Molecular Neurology, University of Helsinki, Helsinki, Finland
- The Folkhälsan Institute of Genetics, Helsinki, Finland
| | - Osmo Hakosalo
- Department of Veterinary Biosciences and Research Programs Unit, Molecular Neurology, University of Helsinki, Helsinki, Finland
- The Folkhälsan Institute of Genetics, Helsinki, Finland
| | - Maria K. Kaukonen
- Department of Veterinary Biosciences and Research Programs Unit, Molecular Neurology, University of Helsinki, Helsinki, Finland
- The Folkhälsan Institute of Genetics, Helsinki, Finland
| | - András M. Komáromy
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan, United States of America
- Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Hannes Lohi
- Department of Veterinary Biosciences and Research Programs Unit, Molecular Neurology, University of Helsinki, Helsinki, Finland
- The Folkhälsan Institute of Genetics, Helsinki, Finland
- * E-mail:
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27
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King JE, Dexter A, Gadi I, Zvereff V, Martin M, Bloom M, Vanderver A, Pizzino A, Schmidt JL. Maternal uniparental isodisomy causing autosomal recessive GM1 gangliosidosis: a clinical report. J Genet Couns 2014; 23:734-41. [PMID: 24777551 DOI: 10.1007/s10897-014-9720-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2013] [Accepted: 03/25/2014] [Indexed: 01/18/2023]
Abstract
Uniparental disomy is a genetic cause of disease that may result in the inheritance of an autosomal recessive condition. A child with developmental delay and hypotonia was seen and found to have severely abnormal myelination. Lysosomal enzyme testing identified an isolated deficiency of beta-galactosidase. Subsequently, homozygous missense mutations in the galactosidase, beta 1 (GLB1) gene on chromosome 3 were found. Parental testing confirmed inheritance of two copies of the same mutated maternal GLB1 gene, and no paternal copy. SNP analysis was also done to confirm paternity. The patient was ultimately diagnosed with autosomal recessive GM1 gangliosidosis caused by maternal uniparental isodisomy. We provide a review of this patient and others in which uniparental disomy (UPD) of a non-imprinted chromosome unexpectedly caused an autosomal recessive condition. This is the first case of GM1 gangliosidosis reported in the literature to have been caused by UPD. It is important for genetic counselors and other health care providers to be aware of the possibility of autosomal recessive disease caused by UPD. UPD as a cause of autosomal recessive disease drastically changes the recurrence risk for families, and discussions surrounding UPD can be complex. Working with families to understand UPD when it occurs requires a secure and trusting counselor-family relationship.
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Affiliation(s)
- Jessica E King
- Department of Neurology, Children's National Medical Center, 111 Michigan Ave. NW, Washington, DC, 20010, USA
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28
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A degenerative retinal process in HIV-associated non-infectious retinopathy. PLoS One 2013; 8:e74712. [PMID: 24069333 PMCID: PMC3775801 DOI: 10.1371/journal.pone.0074712] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Accepted: 08/04/2013] [Indexed: 01/04/2023] Open
Abstract
HIV retinopathy is the most common non-infectious complication in the eyes of HIV-positive individuals. Oncotic lesions in the retinal nerve fiber layer, referred to as cotton wool spots (CWS), and intraretinal (IR) hemorrhages are frequently observed but are not unique to this pathology. HIV-positive patients have impaired color vision and contrast sensitivity, which worsens with age. Evidence of inner-retinal lesions and damage have been documented ophthalmoscopically, however their long term structural effect has not been investigated. It has been hypothesized that they may be partially responsible for loss of visual function and visual field. In this study we utilized clinical data, retinal imaging and transcriptomics approaches to comprehensively interrogate non-infectious HIV retinopathy. The methods employed encompassed clinical examinations, fundus photography, indirect ophthalmoscopy, Farmsworth-Munsell 100 hue discrimination testing and Illumina BeadChip analyses. Here we show that changes in the outer retina, specifically in the retinal pigment epithelium (RPE) and photoreceptor outer segments (POS) contribute to vision changes in non-infectious HIV retinopathy. We find that in HIV-positive retinae there is an induction of rhodopsin and other transcripts (including PDE6A, PDE6B, PDE6G, CNGA1, CNGB1, CRX, NRL) involved in visual transduction, as well as structural components of the rod photoreceptors (ABCA4 and ROM1). This is consistent with an increased rate of renewal of rod outer segments induced via increased phagocytosis by HIV-infected RPE previously reported in culture. Cone-specific transcripts (OPN1SW, OPN1LW, PDE6C, PDE6H and GRK7) are uniformly downregulated in HIV positive retina, likely due to a partial loss of cone photoreceptors. Active cotton wool spots and intraretinal hemorrhages (IRH) may not affect photoreceptors directly and the interaction of photoreceptors with the aging RPE may be the key to the progressive vision changes in HIV-positive patients.
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29
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Abstract
Emerging evidence suggests neuroprotective functions of vitamin K and/or vitamin K-dependent proteins. We investigated the effect of dietary vitamin K on retina aging (thinning). Female Sprague-Dawley rats were maintained from weaning on low (80 microg kg(-1) diet), adequate (500 microg kg(-1) diet) or high (2000 microg kg(-1) diet) levels of vitamin K1 (phylloquinone). Relative concentrations of brain vitamin K associated with these diets were 1: 3.3: 25 (K1) and 1: 2.7: 9.0 (menaquinone-4). Histomorphometry of old (21 month) rats revealed positive associations between vitamin K and thickness of retina layers, especially in the equatorial/peripheral retina. No association of diet and retina thickness was detected among young (6 month) animals. The sparing effect of vitamin K in the retina was most evident in the inner plexiform layer and in the photoreceptor inner and outer segments. Surprisingly, we observed no effect of vitamin K on the age-dependent loss of photoreceptor cells, interneurons or ganglion cells. These data suggest a role for vitamin K in maintaining the aging retina and suggest that the sparing effect of vitamin K does not reflect the survival-promoting (anti-apoptotic) activities of vitamin K-dependent proteins.
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Affiliation(s)
- Isabelle Carrié
- Department of Nutrition, Université de Montréal, Montréal, Qué., Canada H3C 3J7
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30
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Carmichael H, Shen Y, T T, Hirschhorn JN, Dauber A. Whole exome sequencing in a patient with uniparental disomy of chromosome 2 and a complex phenotype. Clin Genet 2013; 84:213-22. [PMID: 23167750 PMCID: PMC3996682 DOI: 10.1111/cge.12064] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2012] [Revised: 11/15/2012] [Accepted: 11/15/2012] [Indexed: 12/11/2022]
Abstract
Whole exome sequencing and chromosomal microarrays are two powerful technologies that have transformed the ability of researchers to search for potentially causal variants in human disease. This study combines these tools to search for causal variants in a patient found to have maternal uniparental isodisomy of chromosome 2. This subject has a complex phenotype including skeletal and renal dysplasia, immune deficiencies, growth failure, retinal degeneration and ovarian insufficiency. Eighteen non-synonymous, rare homozygous variants were identified on chromosome 2. Additionally, five genes with compound heterozygous mutations were detected on other chromosomes that could lead to a disease phenotype independent of the uniparental disomy found in this case. Several candidate genes with potential connection to the phenotype are described but none are definitively proven to be causal. This study highlights the potential for detection of a large number of candidate genes using whole exome sequencing complicating interpretation in both the research and clinical settings. Forums must be created for publication and sharing of detailed phenotypic and genotypic reports to facilitate further biological discoveries and clinical counseling.
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Affiliation(s)
| | - Yiping Shen
- Department of Laboratory Medicine, Boston Children's Hospital
- Department of Pathology, Harvard Medical School
| | - Thutrang T
- Division of Endocrinology, Boston Children’s Hospital
- Center for Basic and Translational Obesity Research, Boston Children’s Hospital
| | - Joel N Hirschhorn
- Division of Endocrinology, Boston Children’s Hospital
- Program in Medical and Population Genetics, Broad Institute
- Center for Basic and Translational Obesity Research, Boston Children’s Hospital
- Department of Genetics, Harvard Medical School
| | - Andrew Dauber
- Division of Endocrinology, Boston Children’s Hospital
- Program in Medical and Population Genetics, Broad Institute
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Suleiman L, Négrier C, Boukerche H. Protein S: A multifunctional anticoagulant vitamin K-dependent protein at the crossroads of coagulation, inflammation, angiogenesis, and cancer. Crit Rev Oncol Hematol 2013; 88:637-54. [PMID: 23958677 DOI: 10.1016/j.critrevonc.2013.07.004] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Revised: 06/18/2013] [Accepted: 07/17/2013] [Indexed: 01/09/2023] Open
Abstract
Since its discovery in 1970, protein S (PS) has emerged as a key vitamin K-dependent natural anticoagulant protein at the crossroads of multiple biological processes, including coagulation, apoptosis, atherosclerosis, angiogenesis/vasculogenesis, and cancer progression. Following the binding to a unique family of protein tyrosine kinase receptors referred to as Tyro-3, Axl and Mer (TAM) receptors, PS can lead to regulation of coagulation, phagocytosis of apoptotic cells, cell survival, activation of innate immunity, vessel integrity and angiogenesis, and local invasion and metastasis. Because of these dynamics and multiple functions of PS, which are largely lost following invalidation of the mouse PROS1 gene, this molecule is currently intensively studied in biomedical research. The purpose of this review is to provide a brief chronicle of the discovery and current understanding of the mechanisms of PS signaling, and how PS and their signaling partners regulate various cellular functions, with a particular focus on TAM receptors.
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Affiliation(s)
- Lutfi Suleiman
- University Claude Bernard, Lyon I, INSERM, Department of Onco-Haematology, EA 4174, France
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Hu P, Wang Y, Meng LL, Qin L, Ma DY, Yi L, Xu ZF. 1q25.2-q31.3 Deletion in a female with mental retardation, clinodactyly, minor facial anomalies but no growth retardation. Mol Cytogenet 2013; 6:30. [PMID: 23915434 PMCID: PMC3766032 DOI: 10.1186/1755-8166-6-30] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Accepted: 06/17/2013] [Indexed: 11/10/2022] Open
Abstract
The reports of 1q25-32 deletion cases are rare. We reported here an 11-year-old Chinese Han female with an interstitial 1q25 deletion displaying mental retardation, clinodactyly of the 5th finger and minor facial anomalies. Notably, the patient did not present growth retardation which is quite common in patients with 1q25-32 deletion encompassing LHX4. The heterozygous deletion in this patient was characterized as 46,XX,del(1)(q25.2-q31.3) with a length of 20.5 Mb according to SNP-array test results. STRP (Short Tandem Repeat Polymorphism) analysis of the family trio indicated the genomic abnormality was de novo with paternal origin. After a genotype-phenotype analysis, we proposed here the loss of a 3.1 Mb critical region including 24 genes within 1q25.2 (chr1:174.5-177.6 Mb, build 36) may account for the mental retardation in patients with 1q25-32 deletion.
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Affiliation(s)
- Ping Hu
- State key Laboratory of Reproductive Medicine, Department of Prenatal Diagnosis, Nanjing Maternity and Child Health Care Hospital Affiliated to Nanjing Medical University, 123 Tianfei Street, Nanjing 210029, China
| | - Yan Wang
- State key Laboratory of Reproductive Medicine, Department of Prenatal Diagnosis, Nanjing Maternity and Child Health Care Hospital Affiliated to Nanjing Medical University, 123 Tianfei Street, Nanjing 210029, China
| | - Lu-Lu Meng
- State key Laboratory of Reproductive Medicine, Department of Prenatal Diagnosis, Nanjing Maternity and Child Health Care Hospital Affiliated to Nanjing Medical University, 123 Tianfei Street, Nanjing 210029, China
| | - Ling Qin
- State key Laboratory of Reproductive Medicine, Department of Prenatal Diagnosis, Nanjing Maternity and Child Health Care Hospital Affiliated to Nanjing Medical University, 123 Tianfei Street, Nanjing 210029, China
| | - Ding-Yuan Ma
- State key Laboratory of Reproductive Medicine, Department of Prenatal Diagnosis, Nanjing Maternity and Child Health Care Hospital Affiliated to Nanjing Medical University, 123 Tianfei Street, Nanjing 210029, China
| | - Long Yi
- Department of Pathology, Nanjing University Medical School, Nanjing 210093, PR China
| | - Zheng-Feng Xu
- State key Laboratory of Reproductive Medicine, Department of Prenatal Diagnosis, Nanjing Maternity and Child Health Care Hospital Affiliated to Nanjing Medical University, 123 Tianfei Street, Nanjing 210029, China
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Conlon TJ, Deng WT, Erger K, Cossette T, Pang JJ, Ryals R, Clément N, Cleaver B, McDoom I, Boye SE, Peden MC, Sherwood MB, Abernathy CR, Alkuraya FS, Boye SL, Hauswirth WW. Preclinical potency and safety studies of an AAV2-mediated gene therapy vector for the treatment of MERTK associated retinitis pigmentosa. HUM GENE THER CL DEV 2013; 24:23-8. [PMID: 23692380 DOI: 10.1089/humc.2013.037] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Abstract Proof of concept for MERTK gene replacement therapy has been demonstrated using different viral vectors in the Royal College of Surgeon (RCS) rat, a well characterized model of recessive retinitis pigmentosa that contains a mutation in the Mertk gene. MERTK plays a key role in renewal of photoreceptor outer segments (OS) by phagocytosis of shed OS tips. Mutations in MERTK cause impaired phagocytic activity and accumulation of OS debris in the interphotoreceptor space that ultimately leads to photoreceptor cell death. In the present study, we conducted a series of preclinical potency and GLP-compliant safety evaluations of an adeno-associated virus type 2 (AAV2) vector expressing human MERTK cDNA driven by the retinal pigment epithelium-specific, VMD2 promoter. We demonstrate the potency of the vector in RCS rats by improved electroretinogram (ERG) responses in treated eyes compared with contralateral untreated controls. Toxicology and biodistribution studies were performed in Sprague-Dawley (SD) rats injected with two different doses of AAV vectors and buffer control. Delivery of vector in SD rats did not result in a change in ERG amplitudes of rod and cone responses relative to balanced salt solution control-injected eyes, indicating that administration of AAV vector did not adversely affect normal retinal function. In vivo fundoscopic analysis and postmortem retinal morphology of the vector-injected eyes were normal compared with controls. Evaluation of blood smears showed the lack of transformed cells in the treated eyes. All injected eyes and day 1 blood samples were positive for vector genomes, and all peripheral tissues were negative. Our results demonstrate the potency and safety of the AAV2-VMD2-hMERTK vector in animal models tested. A GMP vector has been manufactured and is presently in clinical trial.
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Affiliation(s)
- Thomas J Conlon
- Powell Gene Therapy Center, Department of Pediatrics, University of Florida, Gainesville, FL 32610, USA.
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Roosing S, van den Born LI, Hoyng CB, Thiadens AAHJ, de Baere E, Collin RWJ, Koenekoop RK, Leroy BP, van Moll-Ramirez N, Venselaar H, Riemslag FCC, Cremers FPM, Klaver CCW, den Hollander AI. Maternal uniparental isodisomy of chromosome 6 reveals a TULP1 mutation as a novel cause of cone dysfunction. Ophthalmology 2013; 120:1239-46. [PMID: 23499059 DOI: 10.1016/j.ophtha.2012.12.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Revised: 12/04/2012] [Accepted: 12/04/2012] [Indexed: 11/28/2022] Open
Abstract
PURPOSE The majority of the genetic causes of autosomal recessive (ar) cone dystrophy (CD) and cone-rod dystrophy (CRD) are currently unknown. We used a high-resolution homozygosity mapping approach in a cohort of patients with CD or CRD to identify new genes for ar cone disorders. DESIGN Case series. PARTICIPANTS A cohort of 159 patients with ar CD and 91 patients with CRD. METHODS The genomes of 83 patients with ar CD and 73 patients with CRD were analyzed for homozygous regions using single nucleotide polymorphism (SNP) microarrays. One patient showed homozygosity of SNPs across chromosome 6, and segregation analysis was performed using microsatellite markers. Direct sequencing of all retinal disease genes on chromosome 6 revealed a novel pathogenic TULP1 mutation in this patient. A cohort of 159 individuals with CD and 91 individuals with CRD was screened for this particular mutation using the restriction enzyme HhaI. The medical history of patients carrying the TULP1 mutation was reviewed and additional ophthalmic examinations were performed, including electroretinography (ERG), perimetry, optical coherence tomography (OCT), fundus autofluorescence (FAF), and fundus photography. MAIN OUTCOME MEASURES TULP1 mutations, age at diagnosis, visual acuity, fundus appearance, color vision defects, visual field, ERG, FAF, and OCT findings. RESULTS In 1 patient, homozygosity mapping and subsequent segregation analysis revealed maternal uniparental disomy (UPD) of chromosome 6. A novel homozygous missense mutation (p.Arg420Ser) was identified in TULP1, whereas no mutations were detected in other retinal disease genes on chromosome 6. The mutation affects a highly conserved amino acid residue in the Tubby domain and is predicted to be pathogenic. The same homozygous mutation was also identified in an additional, unrelated patient with CRD. Both patients carrying the p.Arg420Ser mutation presented with a bull's eye maculopathy. The first patient had progressive loss of visual acuity with a relatively preserved ERG, whereas the second patient developed loss of visual acuity, peripheral degeneration, and severely reduced ERG responses in a cone-rod pattern. CONCLUSIONS Maternal UPD of chromosome 6 unmasked a mutation in the TULP1 gene as a novel cause of cone dysfunction. This expands the disease spectrum of TULP1 mutations from Leber congenital amaurosis and early-onset retinitis pigmentosa to cone-dominated disease. FINANCIAL DISCLOSURE(S) The author(s) have no proprietary or commercial interest in any materials discussed in this article.
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Affiliation(s)
- Susanne Roosing
- Department of Human Genetics, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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Haudry C, de Lonlay P, Malan V, Bole-Feysot C, Assouline Z, Pruvost S, Brassier A, Bonnefont JP, Munnich A, Rötig A, Lebre AS. Maternal uniparental disomy of chromosome 2 in a patient with a DGUOK mutation associated with hepatocerebral mitochondrial DNA depletion syndrome. Mol Genet Metab 2012; 107:700-4. [PMID: 23141463 DOI: 10.1016/j.ymgme.2012.10.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Revised: 10/10/2012] [Accepted: 10/10/2012] [Indexed: 12/11/2022]
Abstract
We report maternal uniparental disomy of chromosome 2 (matUPD2) in a 9-month-old girl presenting with hepatocerebral mitochondrial DNA depletion syndrome. This patient was homozygous for the c.352C>T (p.Arg118Cys) mutation in DGUOK gene. The proband's mother was heterozygous for the mutation was absent in DNA of the father. For proband, the absence of paternal contribution at the DGUOK locus prompted us to exclude intragenic DGUOK deletion of the paternal allele with Multiplex ligation-dependent probe amplification (MLPA) analysis. We also excluded non-paternity by studying various markers at different loci. Then we performed an analysis of copy number variations and absence of heterozygosity (AOH) on the proband DNA using high resolution oligonucleotides microarray. Several large regions of AOH with no copy number change were detected on chromosome 2 and one of these AOH regions encompassed DGUOK gene. These results were confirmed with haplotype analysis using polymorphic markers. Informative SNPs and microsatellites markers spanning the whole chromosome 2 showed a matUPD2 with heterodisomy and isodisomy regions, the absence of paternal allele and presence of two maternal alleles, with only one maternal allele on the region of DGUOK locus in 2p13.1. This is the first demonstration of matUPD2 with segmental isodisomy at 2p13.1 locus in hepatocerebral mitochondrial DNA depletion syndrome. The identification of UPD2 will impact genetic counseling for the proband's parents. Because the recurrence risk for UPD2 is very low, the risk for disease in further offspring for this couple is negligible.
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Affiliation(s)
- Coralie Haudry
- Assistance Publique-Hôpitaux de Paris, Services de Génétique, de Cytogénétique et de Maladies Métaboliques, Hôpital Necker-Enfants Malades, 149, rue de Sèvres 75743 Paris cedex 15, France
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Homozygous mutation in MERTK causes severe autosomal recessive retinitis pigmentosa. Eur J Ophthalmol 2012; 22:647-53. [PMID: 22180149 DOI: 10.5301/ejo.5000096] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/17/2011] [Indexed: 11/20/2022]
Abstract
PURPOSE Gene identification in retinitis pigmentosa is a prerequisite to future therapies. Accordingly, autosomal recessive retinitis pigmentosa families were genotyped to search for causative mutations. METHODS Members of a consanguineous Moroccan family had standard ophthalmologic examination, optical coherence tomography-3 scan, autofluorescence testing, and electroretinogram. Their DNA was genotyped with the 250K SNP microchip (Affymetrix) and homozygosity mapping was done. MERTK exons were polymerase chain reaction amplified and sequenced. RESULTS Two sisters and one brother out of 6 siblings had rod cone dystrophy type of retinitis pigmentosa. Salient features were night blindness starting in early infancy, dot-like whitish deposits in fovea and macula with corresponding autofluorescent dots in youngest patients, decreased visual acuity, and cone responses higher than rod responses at electroretinogram. The patients were homozygous in regions from chromosomes 2 and 8, but only that of chromosome 2 was inherited from a common ancestor. Sequencing of the MERTK gene belonging to the chromosome 2 region showed that the 3 affected patients carried a novel homozygous mutation in exon 17, c.2323C>T, leading to p.Arg775X, while their unaffected brothers and sister, parents, and paternal grandfather were heterozygous. CONCLUSIONS MERTK mutations lead to severe retinitis pigmentosa with discrete dot-like autofluorescent deposits at early stages, which are a hallmark of this MERTK-specific dystrophy.
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Ou X, Liu C, Chen S, Yu J, Zhang Y, Liu S, Sun H. Complete paternal uniparental isodisomy for Chromosome 2 revealed in a parentage testing case. Transfusion 2012; 53:1266-9. [PMID: 22924962 DOI: 10.1111/j.1537-2995.2012.03863.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Uniparental disomy (UPD) is a rare cytogenetic event that has previously been reported mostly via genetic analysis of patients with phenotypes of recessive diseases. The incidence of UPD of any chromosome is estimated to be approximately1:3500 live births. CASE REPORT In a case of disputed paternity involving a phenotypically normal male child, mother-child exclusions were observed at five short tandem repeat markers, which were all located on Chromosome 2. Ten additional dinucleotide repeat markers spanning both arms of Chromosome 2 were investigated. The results revealed that the child was homozygous for all markers tested with all alleles originating from a single paternal Chromosome 2, which was consistent with paternal UPD for Chromosome 2. CONCLUSION This case and other previous reports demonstrate that UPD poses a high risk for false exclusion and incorrect expert opinion. Furthermore, this case highlights that a conclusion of exclusion of paternity or maternity should not be postulated if multiple genetic incompatibilities are located on the same chromosome because of the occurrence of UPD.
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Affiliation(s)
- Xueling Ou
- Department of Forensic Medicine, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, PR China
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Deng WT, Dinculescu A, Li Q, Boye SL, Li J, Gorbatyuk MS, Pang J, Chiodo VA, Matthes MT, Yasumura D, Liu L, Alkuraya FS, Zhang K, Vollrath D, LaVail MM, Hauswirth WW. Tyrosine-mutant AAV8 delivery of human MERTK provides long-term retinal preservation in RCS rats. Invest Ophthalmol Vis Sci 2012; 53:1895-904. [PMID: 22408006 DOI: 10.1167/iovs.11-8831] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE The absence of Mertk in RCS rats results in defective RPE phagocytosis, accumulation of outer segment (OS) debris in the subretinal space, and subsequent death of photoreceptors. Previous research utilizing Mertk gene replacement therapy in RCS rats provided proof of concept for treatment of this form of recessive retinitis pigmentosa (RP); however, the beneficial effects on retinal function were transient. In the present study, we evaluated whether delivery of a MERTK transgene using a tyrosine-mutant AAV8 capsid could lead to more robust and longer-term therapeutic outcomes than previously reported. METHODS An AAV8 Y733F vector expressing a human MERTK cDNA driven by a RPE-selective promoter was administrated subretinally at postnatal day 2. Functional and morphological analyses were performed at 4 months and 8 months post-treatment. Retinal vasculature and Müller cell activation were analyzed by quantifying acellular capillaries and glial fibrillary acidic protein immunostaining, respectively. RESULTS Electroretinographic responses from treated eyes were more than one-third of wild-type levels and OS were well preserved in the injection area even at 8 months. Rescue of RPE phagocytosis, prevention of retinal vasculature degeneration, and inhibition of Müller cell activation were demonstrated in the treated eyes for at least 8 months. CONCLUSIONS This research describes a longer and much more robust functional and morphological rescue than previous studies. We also demonstrate for the first time that an AAV8 mutant capsid serotype vector has a substantial therapeutic potential for RPE-specific gene delivery. These results suggest that tyrosine-mutant AAV8 vectors hold promise for the treatment of individuals with MERTK-associated RP.
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Affiliation(s)
- Wen-Tao Deng
- Department of Ophthalmology, College of Medicine, University of Florida, 1600 SW Archer Road, Gainesville, FL 32610, USA.
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Giovannoni I, Terracciano A, Gennari F, David E, Francalanci P, Santorelli FM. Paternal isodisomy of chromosome 2 in a child with bile salt export pump deficiency. Hepatol Res 2012; 42:327-31. [PMID: 22364601 DOI: 10.1111/j.1872-034x.2011.00925.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
We describe a child with progressive familial intrahepatic cholestasis (PFIC) of type 2 inherited as uniparental isodisomy of chromosome 2. Bile salt export pump (BSEP) deficiency is a severe, genetically determined subtype PFIC caused by mutations in ABCB11, the gene encoding a bile salt transporter protein. Clinical and pathological diagnosis in PFIC2 is corroborated by an ample array of ABCB11 mutations, inherited in an autosomal recessive fashion. We report clinical, pathological, and molecular studies in a child with PFIC2. A 5.5-year-old boy harbored a described pathogenic mutation (p.R832C) in ABCB11. The mutation was found to be homozygous in the patient and heterozygous in DNA from paternal, but not maternal blood. Having ruled out maternal gene deletion and somatic mosaicism, we showed that the child had inherited an isodisomic paternal chromosome 2, including the 2q31.1 region where ABCB11 is located. The present report is the first description of uniparental isodisomy in a hepatic heritable disorder. Recognizing isodisomic transmission may have a significant impact on genetic counseling helping to define the risk of recurrence in subsequent pregnancies.
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Affiliation(s)
- Isabella Giovannoni
- Units of Pathology Molecular Medicine and Neurosciences Hepatic Surgery, Children's Hospital Bambino Gesù, Rome Unit of Pathology, Molinette Hospital, Turin IRCCS Fondazione Stella Maris, Pisa, Italy
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Abstract
BACKGROUND Retinitis pigmentosa (RP) is a group of genetically heterogeneous diseases with progressive degeneration of the retina. The condition can be inherited as an autosomal dominant, autosomal recessive, and X-linked trait. METHODS We report on two female twin pairs. One twin of each pair is affected with RP, the other twin is unaffected, both clinically and functionally.Molecular analysis in both twins included zygosity determination, arrayed primer extension chip analysis for autosomal recessive and dominant RP, sequencing of the entire RPGR gene, and analysis of X-chromosome inactivation status. RESULTS Both unrelated twin pairs were genetically identical. Of the potential pathogenetic mechanisms, skewed X-inactivation was excluded on leukocytes. Autosomal recessive RP and autosomal dominant RP arrayed primer extension chip analysis result was completely normal, excluding known mutations in known genes as the cause of disease in the affected twins. Sequencing excluded mutations in RPGR. A postzygotic recessive or dominant genetic mutation of an RP gene is not impossible. A postfertilization error as a potential cause of uniparental isodisomy is unlikely albeit not entirely impossible. CONCLUSION The authors report on the second and third unrelated identical twin pair discordant for RP. The exact cause of the condition and the explanation of the clinical discordance remain elusive.
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The consequences of uniparental disomy and copy number neutral loss-of-heterozygosity during human development and cancer. Biol Cell 2011; 103:303-17. [PMID: 21651501 DOI: 10.1042/bc20110013] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
UPD (uniparental disomy) describes the inheritance of a pair of chromosomes from only one parent. Mechanisms that lead to UPD include trisomy rescue, gamete complementation, monosomy rescue and somatic recombination. Most of these mechanisms can involve aberrant chromosomes, particularly isochromosomes and Robertsonian translocations. In the last decade, the number of UPD cases reported in the literature has increased exponentially. This is partly due to the advances in genomic technologies that have allowed for high-resolution SNP (single nucleotide polymorphism) studies, which have complemented traditional methods relying on polymorphic microsatellite markers. In this review, we discuss aberrant cellular mechanisms leading to UPD and their impact on gene expression. Special emphasis is placed on the unmasking of mutant recessive alleles and the disruption of imprinted gene dosage, which give rise to specific and recurrent imprinting phenotypes. Finally, we discuss how copy number maps determined from SNP array datasets have helped identify not only deletions and duplications but also recurrent copy number neutral regions of loss-of-heterozygosity, which have been reported in many cancer types and that may constitute an important driving force in cancer. These tiny regions of UPD also alter imprinted gene dosage, which may have cumulative tumourgenic effects in addition to that of unmasking homozygous cancer-associated mutations.
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Maddox DM, Hicks WL, Vollrath D, LaVail MM, Naggert JK, Nishina PM. An ENU-induced mutation in the Mertk gene (Mertknmf12) leads to a slow form of retinal degeneration. Invest Ophthalmol Vis Sci 2011; 52:4703-9. [PMID: 21436282 PMCID: PMC3175976 DOI: 10.1167/iovs.10-7077] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Revised: 02/15/2011] [Accepted: 03/07/2011] [Indexed: 12/14/2022] Open
Abstract
PURPOSE To determine the basis and to characterize the phenotype of a chemically induced mutation in a mouse model of retinal degeneration. METHODS Screening by indirect ophthalmoscopy identified a line of N-ethyl-N-nitrosourea (ENU) mutagenized mice demonstrating retinal patches. Longitudinal studies of retinal histologic sections showed photoreceptors in the peripheral retina undergoing slow, progressive degeneration. The mutation was named neuroscience mutagenesis facility 12 (nmf12), and mapping localized the critical region to Chromosome 2. RESULTS Sequencing of nmf12 DNA revealed a point mutation in the c-mer tyrosine kinase gene, designated Mertk(nmf12). We detected elevated levels of tumor necrosis factor (Tnf, previously Tnfa) in retinas of Mertk(nmf12) homozygotes relative to wild-type controls and investigated whether the increase of TNF, an inflammatory cytokine produced by macrophages/monocytes that signals intracellularly to cause necrosis or apoptosis, could underlie the retinal degeneration observed in Mertk(nmf12) homozygotes. Mertk(nmf12) homozygous mice were mated to mice lacking the entire Tnf gene and partial coding sequences of the Lta (Tnfb) and Ltb (Tnfc) genes.(2) B6.129P2-Ltb/Tnf/Lta(tm1Dvk)/J homozygotes did not exhibit a retinal degeneration phenotype and will, hereafter, be referred to as Tnfabc(-/-) mice. Surprisingly, mice homozygous for both the Mertk(nmf12) and the Ltb/Tnf/Lta(tm1Dvk) allele (Tnfabc(-/-)) demonstrated an increase in the rate of retinal degeneration. CONCLUSIONS These findings illustrate that a mutation in the Mertk gene leads to a significantly slower progressive retinal degeneration compared with other alleles of Mertk. These results demonstrate that TNF family members play a role in protecting photoreceptors of Mertk(nmf12) homozygotes from cell death.
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Affiliation(s)
- Dennis M. Maddox
- From the Nishina Laboratory and
- Genetic Resource Sciences, The Jackson Laboratory, Bar Harbor, Maine
| | | | - Douglas Vollrath
- Stanford University School of Medicine, Palo Alto, California; and
| | - Matthew M. LaVail
- Beckman Vision Center, University of California, San Francisco, California
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Sparrow JR, Hicks D, Hamel CP. The retinal pigment epithelium in health and disease. Curr Mol Med 2011; 10:802-23. [PMID: 21091424 DOI: 10.2174/156652410793937813] [Citation(s) in RCA: 417] [Impact Index Per Article: 32.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2010] [Accepted: 09/13/2010] [Indexed: 12/15/2022]
Abstract
Retinal pigment epithelial cells (RPE) constitute a simple layer of cuboidal cells that are strategically situated behind the photoreceptor (PR) cells. The inconspicuousness of this monolayer contrasts sharply with its importance [1]. The relationship between the RPE and PR cells is crucial to sight; this is evident from basic and clinical studies demonstrating that primary dysfunctioning of the RPE can result in visual cell death and blindness. RPE cells carry out many functions including the conversion and storage of retinoid, the phagocytosis of shed PR outer segment membrane, the absorption of scattered light, ion and fluid transport and RPE-PR apposition. The magnitude of the demands imposed on this single layer of cells in order to execute these tasks, will become apparent to the reader of this review as will the number of clinical disorders that take origin from these cells.
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Affiliation(s)
- J R Sparrow
- Department of Ophthalmology, Columbia University, New York, NY 10032, USA.
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Stone EM, Cideciyan AV, Aleman TS, Scheetz TE, Sumaroka A, Ehlinger MA, Schwartz SB, Fishman GA, Traboulsi EI, Lam BL, Fulton AB, Mullins RF, Sheffield VC, Jacobson SG. Variations in NPHP5 in patients with nonsyndromic leber congenital amaurosis and Senior-Loken syndrome. ACTA ACUST UNITED AC 2011; 129:81-7. [PMID: 21220633 DOI: 10.1001/archophthalmol.2010.330] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
OBJECTIVE To investigate whether mutations in NPHP5 can cause Leber congenital amaurosis (LCA) without early-onset renal disease. METHODS DNA samples from 276 individuals with nonsyndromic LCA were screened for variations in the NPHP5 gene. Each had been previously screened for mutations in 8 known LCA genes without identifying a disease-causing genotype. RESULTS Nine of the 276 LCA probands (3.2%) harbored 2 plausible disease-causing mutations (7 different alleles) in NPHP5. Four of these have been previously reported in patients with Senior-Loken syndrome (F141del, R461X, H506del, and R489X) and 3 are novel (A111del, E346X, and R455X). All 9 patients had severe visual loss from early childhood but none had overt renal disease in the first decade of life. Two patients were diagnosed with nephronophthisis in the second decade. Retinal imaging studies showed retained photoreceptor nuclei and retinal pigment epithelium integrity mainly in the cone-rich central retina, a phenotype with strong similarities to that of NPHP6 disease. CONCLUSIONS Mutations in NPHP5 can cause LCA without early-onset renal disease. Abnormalities observed in the photoreceptor outer segments (a cilial structure) may explain the severe visual loss in NPHP5 -associated LCA. Clinical Relevance The persistence of central photoreceptor nuclei despite severe visual loss in NPHP5 disease is encouraging for future therapeutic interventions.
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Affiliation(s)
- Edwin M Stone
- Department of Ophthalmology and Visual Sciences, The University of Iowa, 375 Newton Rd, 4111 MERF, Iowa City, IA 52242, USA.
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Baskin B, Geraghty M, Ray PN. Paternal isodisomy of chromosome 2 as a cause of long chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) deficiency. Am J Med Genet A 2010; 152A:1808-11. [PMID: 20583174 DOI: 10.1002/ajmg.a.33462] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency is an autosomal recessive disorder affecting mitochondrial fatty acid oxidation due to mutations in the HADHA gene. We report on a 22-month-old child who was identified on expanded newborn screening with an abnormal acylcarnitine pattern and increased C14OH. Molecular analysis showed that the child was homozygous for the common mutation, c.1526G > C (p.Glu510Gln) in the HADHA gene. Carrier testing on the parental samples revealed that the father was heterozygous for the mutation whereas the mother did not carry the mutation. Short tandem repeat testing with markers covering both short and long arms of chromosome 2 showed that the child has paternal uniparental isodisomy. We highlight the importance of parental testing in cases of homozygosity in autosomal recessive disorders and its impact on genetic counseling of the family.
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Affiliation(s)
- Berivan Baskin
- Division of Molecular Genetics, Department of Paediatric Laboratory Medicine, The Hospital for Sick Children, Toronto, Canada.
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Nimmo G, Monsonego S, Descartes M, Franklin J, Steinberg S, Braverman N. Rhizomelic chrondrodysplasia punctata type 2 resulting from paternal isodisomy of chromosome 1. Am J Med Genet A 2010; 152A:1812-7. [PMID: 20583171 DOI: 10.1002/ajmg.a.33489] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Rhizomelic chondrodysplasia punctata (RCDP) is an autosomal-recessive disorder resulting from mutations in one of three peroxisomal genes essential for ether lipid biosynthesis, PEX7 (RCDP1), GNPAT (RCDP2), and AGPS (RCDP3). Affected patients have characteristic features including shortening of the proximal long bones, epiphyseal stippling, bilateral cataracts, growth and developmental delays. Whereas the majority of patients have RCDP type 1, around 5% have RCDP type 2 or 3. We identified a patient with RCDP type 2 and an apparent homozygous deletion, c.1428delC, after full sequencing of his GNPAT genes. The father was heterozygous for this mutation, while sequencing of the maternal GNPAT genes revealed only wild-type sequence. Southern analyses performed on parental gDNA did not show evidence of a maternal gene deletion. Amplification and fragment analysis of dinucleotide repeat markers spanning chromosome 1 in the patient and both parents revealed paternal uniparental inheritance. We discuss the potential mechanisms causing uniparental disomy (UPD) in this patient and review the literature on chromosome 1 UPD. The absence of non-RCDP clinical features in this patient was consistent with previous literature supporting the absence of imprinted genes on chromosome 1. This first description of RCDP caused by UPD dramatically changes the parental recurrence risk, highlighting the value of obtaining parental genotypes when the proband has a putative homozygous mutation by sequence analysis.
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Affiliation(s)
- Graeme Nimmo
- Montreal Children's Hospital Research Institute, McGill University, Montreal, Quebec, Canada
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Manoli I, Golas G, Westbroek W, Vilboux T, Markello TC, Introne W, Maynard D, Pederson B, Tsilou E, Jordan MB, Hart PS, White JG, Gahl WA, Huizing M. Chediak-Higashi syndrome with early developmental delay resulting from paternal heterodisomy of chromosome 1. Am J Med Genet A 2010; 152A:1474-83. [PMID: 20503323 DOI: 10.1002/ajmg.a.33389] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Chediak-Higashi syndrome (CHS) is a rare autosomal recessive disease characterized by variable oculocutaneous albinism, immunodeficiency, mild bleeding diathesis, and an accelerated lymphoproliferative state. Abnormal lysosome-related organelle membrane function leads to the accumulation of large intracellular vesicles in several cell types, including granulocytes, melanocytes, and platelets. This report describes a severe case of CHS resulting from paternal heterodisomy of chromosome 1, causing homozygosity for the most distal nonsense mutation (p.E3668X, exon 50) reported to date in the LYST/CHS1 gene. The mutation is located in the WD40 region of the CHS1 protein. The patient's fibroblasts expressed no detectable CHS1. Besides manifesting the classical CHS findings, the patient exhibited hypotonia and global developmental delays, raising concerns about other effects of heterodisomy. An interstitial 747 kb duplication on 6q14.2-6q14.3 was identified in the propositus and paternal samples by comparative genomic hybridization. SNP genotyping revealed no additional whole chromosome or segmental isodisomic regions or other dosage variations near the crossover breakpoints on chromosome 1. Unmasking of a separate autosomal recessive cause of developmental delay, or an additive effect of the paternal heterodisomy, could underlie the severity of the phenotype in this patient.
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Affiliation(s)
- Irini Manoli
- Section on Human Biochemical Genetics, Medical Genetics Branch, National Human Genome Research Institute, NIH, Bethesda, Maryland, USA.
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Cideciyan AV. Leber congenital amaurosis due to RPE65 mutations and its treatment with gene therapy. Prog Retin Eye Res 2010; 29:398-427. [PMID: 20399883 DOI: 10.1016/j.preteyeres.2010.04.002] [Citation(s) in RCA: 178] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Leber congenital amaurosis (LCA) is a rare hereditary retinal degeneration caused by mutations in more than a dozen genes. RPE65, one of these mutated genes, is highly expressed in the retinal pigment epithelium where it encodes the retinoid isomerase enzyme essential for the production of chromophore which forms the visual pigment in rod and cone photoreceptors of the retina. Congenital loss of chromophore production due to RPE65-deficiency together with progressive photoreceptor degeneration cause severe and progressive loss of vision. RPE65-associated LCA recently gained recognition outside of specialty ophthalmic circles due to early success achieved by three clinical trials of gene therapy using recombinant adeno-associated virus (AAV) vectors. The trials were built on multitude of basic, pre-clinical and clinical research defining the pathophysiology of the disease in human subjects and animal models, and demonstrating the proof-of-concept of gene (augmentation) therapy. Substantial gains in visual function of clinical trial participants provided evidence for physiologically relevant biological activity resulting from a newly introduced gene. This article reviews the current knowledge on retinal degeneration and visual dysfunction in animal models and human patients with RPE65 disease, and examines the consequences of gene therapy in terms of improvement of vision reported.
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Affiliation(s)
- Artur V Cideciyan
- Scheie Eye Institute, University of Pennsylvania, 51 North 39th St, Philadelphia, PA 19104, USA.
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Novel mutations in MERTK associated with childhood onset rod-cone dystrophy. Mol Vis 2010; 16:369-77. [PMID: 20300561 PMCID: PMC2838735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2009] [Accepted: 03/02/2010] [Indexed: 10/27/2022] Open
Abstract
PURPOSE To report the clinical phenotype in patients with a retinal dystrophy associated with novel mutations in the MER tyrosine kinase (MERTK) gene. METHODS A consanguineous family of Middle Eastern origin was identified, and affected members underwent a full clinical evaluation. Linkage analysis was performed using the Affymetrix 50K chip. Regions of homozygosity were identified. The positional candidate genes protocadherin 21 (PCDH21), retinal G protein-coupled receptor (RGR), and MERTK were polymerase chain reaction (PCR) amplified and sequenced. Long-range PCR was performed to characterize the deletion. Two hundred and ninety-two probands with autosomal recessive, childhood onset, retinal dystrophies were analyzed using the Asper Ophthalmics Leber congenital amaurosis chip to screen for known MERTK mutations. RESULTS Analysis of a 50K-Affymetrix whole genome scan identified three regions of homozygosity on chromosomes 2 and 10. Screening of the candidate gene MERTK showed a possible deletion of exon 8. Long-range PCR identified a ~9 kb deletion within MERTK that removes exon 8. Screening of DNA from a panel of Saudi Arabian patients with autosomal recessive retinitis pigmentosa identified a second consanguineous family with the same mutation. One patient with a known MERTK mutation (p.R651X) was identified using the Asper Ophthalmics Leber congenital amaurosis chip. Further screening of the gene identified a second novel splice site mutation in intron 1. The phenotype associated with these identified MERTK mutations is of a childhood onset rod-cone dystrophy with early macular atrophy. The optical coherence tomography (OCT) appearance is distinctive with evidence of debris beneath the sensory retina. CONCLUSIONS Mutations in MERTK are a rare cause of retinal dystrophy. Non homologous recombination between Alu Y repeats near or within disease genes may be an important cause of retinal dystrophies.
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Hamvas A, Nogee LM, Wegner DJ, Depass K, Christodoulou J, Bennetts B, McQuade LR, Gray PH, Deterding RR, Carroll TR, Kammesheidt A, Kasch LM, Kulkarni S, Cole FS. Inherited surfactant deficiency caused by uniparental disomy of rare mutations in the surfactant protein-B and ATP binding cassette, subfamily a, member 3 genes. J Pediatr 2009; 155:854-859.e1. [PMID: 19647838 PMCID: PMC2794197 DOI: 10.1016/j.jpeds.2009.06.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2008] [Revised: 05/01/2009] [Accepted: 06/03/2009] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To characterize inheritance of homozygous, rare, recessive loss-of-function mutations in surfactant protein-B (SFTPB) or ATP binding cassette, subfamily A, member 3 (ABCA3) genes in newborns with lethal respiratory failure. STUDY DESIGN We resequenced genes from parents whose infants were homozygous for mutations in SFTPB or ABCA3. For infants with only 1 heterozygous parent, we performed microsatellite analysis for chromosomes 2 (SFTPB) and 16 (ABCA3). RESULTS We identified 1 infant homozygous for the g.1549C > GAA mutation (121ins2) in SFTPB for whom only the mother was heterozygous and 3 infants homozygous for mutations in ABCA3 (p.K914R, p.P147L, and c.806_7insGCT) for whom only the fathers were heterozygous. For the SP-B-deficient infant, microsatellite markers confirmed maternal heterodisomy with segmental isodisomy. Microsatellite analysis confirmed paternal isodisomy for the 3 ABCA3-deficient infants. Two ABCA3-deficient infants underwent lung transplantation at 3 and 5 months of age, respectively, and 2 infants died. None exhibited any nonpulmonary phenotype. CONCLUSIONS Uniparental disomy should be suspected in infants with rare homozygous mutations in SFTPB or ABCA3. Confirmation of parental carrier status is important to provide recurrence risk and to monitor expression of other phenotypes that may emerge through reduction to homozygosity of recessive alleles.
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Affiliation(s)
- Aaron Hamvas
- Edward Mallinckrodt Department of Pediatrics, Washington University School of Medicine and St. Louis Children's Hospital, St. Louis, MO 63110, USA.
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