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The landscape of submicroscopic structural variants at the OPN1LW/OPN1MW gene cluster on Xq28 underlying blue cone monochromacy. Proc Natl Acad Sci U S A 2022; 119:e2115538119. [PMID: 35759666 PMCID: PMC9271157 DOI: 10.1073/pnas.2115538119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Blue cone monochromacy (BCM) is an X-linked retinal disorder characterized by low vision, photoaversion, and poor color discrimination. BCM is due to the lack of long-wavelength-sensitive and middle-wavelength-sensitive cone photoreceptor function and caused by mutations in the OPN1LW/OPN1MW gene cluster on Xq28. Here, we investigated the prevalence and the landscape of submicroscopic structural variants (SVs) at single-base resolution in BCM patients. We found that about one-third (n = 73) of the 213 molecularly confirmed BCM families carry an SV, most commonly deletions restricted to the OPN1LW/OPN1MW gene cluster. The structure and precise breakpoints of the SVs were resolved in all but one of the 73 families. Twenty-two families-all from the United States-showed the same SV, and we confirmed a common ancestry of this mutation. In total, 42 distinct SVs were identified, including 40 previously unreported SVs, thereby quadrupling the number of precisely mapped SVs underlying BCM. Notably, there was no "region of overlap" among these SVs. However, 90% of SVs encompass the upstream locus control region, an essential enhancer element. Its minimal functional extent based on deletion mapping in patients was refined to 358 bp. Breakpoint analyses suggest diverse mechanisms underlying SV formation as well as in one case the gene conversion-based exchange of a 142-bp deletion between opsin genes. Using parsimonious assumptions, we reconstructed the composition and copy number of the OPN1LW/OPN1MW gene cluster prior to the mutation event and found evidence that large gene arrays may be predisposed to the occurrence of SVs at this locus.
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Next-Generation Sequencing Applications for Inherited Retinal Diseases. Int J Mol Sci 2021; 22:ijms22115684. [PMID: 34073611 PMCID: PMC8198572 DOI: 10.3390/ijms22115684] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 05/21/2021] [Accepted: 05/22/2021] [Indexed: 12/12/2022] Open
Abstract
Inherited retinal diseases (IRDs) represent a collection of phenotypically and genetically diverse conditions. IRDs phenotype(s) can be isolated to the eye or can involve multiple tissues. These conditions are associated with diverse forms of inheritance, and variants within the same gene often can be associated with multiple distinct phenotypes. Such aspects of the IRDs highlight the difficulty met when establishing a genetic diagnosis in patients. Here we provide an overview of cutting-edge next-generation sequencing techniques and strategies currently in use to maximise the effectivity of IRD gene screening. These techniques have helped researchers globally to find elusive causes of IRDs, including copy number variants, structural variants, new IRD genes and deep intronic variants, among others. Resolving a genetic diagnosis with thorough testing enables a more accurate diagnosis and more informed prognosis and should also provide information on inheritance patterns which may be of particular interest to patients of a child-bearing age. Given that IRDs are heritable conditions, genetic counselling may be offered to help inform family planning, carrier testing and prenatal screening. Additionally, a verified genetic diagnosis may enable access to appropriate clinical trials or approved medications that may be available for the condition.
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Haseoka T, Inagaki R, Kurata K, Arai S, Takagi Y, Suzuki H, Hikoya A, Nishimura K, Hotta Y, Sato M. Usefulness of handheld electroretinogram system for diagnosing blue-cone monochromatism in children. Jpn J Ophthalmol 2020; 65:23-29. [PMID: 33135089 DOI: 10.1007/s10384-020-00782-9] [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: 05/13/2020] [Accepted: 09/09/2020] [Indexed: 11/26/2022]
Abstract
PURPOSE To report the diagnosis of three childhood patients with blue-cone monochromatism (BCM) using S-cone electroretinograms (ERG) recorded with RETeval® Complete. STUDY DESIGN Prospective clinical study. METHODS We examined three boys initially suspected of having rod monochromatism. S-cone ERG was performed with red background and blue flashed light stimulation using two different intensities: 0.25 cd × s/m2 and 1 cd × s/m2. RESULTS Case 1 was a 12-year-old boy with a visual acuity of 0.1 OU. Case 2 was an 8-year-old boy with a visual acuity of 0.3 OD and 0.2 OS. Both cases showed a myopic fundus and nystagmus without any other ocular abnormalities. Case 3 was a 6-year-old boy with a visual acuity of 0.3 OD and 0.4 OS. He also showed myopic fundus changes, but nystagmus was not observed. Rod and maximal responses recorded with RETeval® were likely to be within normal range; however, cone responses were absent in all cases. S-cone ERGs showed positive responses at 40 ms with 0.25 cd × s/m2 intensity in Case 2, and at approximately 30-40 ms with 1.0 cd × s/m2 intensity in all three cases. These ERG findings led to a diagnosis of BCM. CONCLUSIONS S-cone ERG of RETeval® was helpful in diagnosing with minimal invasion BCM in childhood patients.
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Affiliation(s)
- Takashi Haseoka
- Department of Ophthalmology, Hamamatsu University School of Medicine, 1-20-1 Handayama, Hamamatsu-shi, Higashi-ku, Shizuoka, 431-3192, Japan
| | - Risako Inagaki
- Department of Ophthalmology, Hamamatsu University School of Medicine, 1-20-1 Handayama, Hamamatsu-shi, Higashi-ku, Shizuoka, 431-3192, Japan
| | - Kentaro Kurata
- Department of Ophthalmology, Hamamatsu University School of Medicine, 1-20-1 Handayama, Hamamatsu-shi, Higashi-ku, Shizuoka, 431-3192, Japan
| | - Shinji Arai
- Department of Ophthalmology, Hamamatsu University School of Medicine, 1-20-1 Handayama, Hamamatsu-shi, Higashi-ku, Shizuoka, 431-3192, Japan
| | - Yuri Takagi
- Department of Ophthalmology, Hamamatsu University School of Medicine, 1-20-1 Handayama, Hamamatsu-shi, Higashi-ku, Shizuoka, 431-3192, Japan
| | - Hiroko Suzuki
- Department of Ophthalmology, Hamamatsu University School of Medicine, 1-20-1 Handayama, Hamamatsu-shi, Higashi-ku, Shizuoka, 431-3192, Japan
| | - Akiko Hikoya
- Department of Ophthalmology, Hamamatsu University School of Medicine, 1-20-1 Handayama, Hamamatsu-shi, Higashi-ku, Shizuoka, 431-3192, Japan
| | - Kasumi Nishimura
- Shizuoka Children's Hospital, Shizuoka, Japan
- Ueno Ganka Clinic Ophthalmology, Shizouka, Japan
| | - Yoshihiro Hotta
- Department of Ophthalmology, Hamamatsu University School of Medicine, 1-20-1 Handayama, Hamamatsu-shi, Higashi-ku, Shizuoka, 431-3192, Japan
| | - Miho Sato
- Department of Ophthalmology, Hamamatsu University School of Medicine, 1-20-1 Handayama, Hamamatsu-shi, Higashi-ku, Shizuoka, 431-3192, Japan.
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Hosono K, Kawase K, Kurata K, Niimi Y, Saitsu H, Minoshima S, Ohnishi H, Yamamoto T, Hikoya A, Tachibana N, Fukao T, Yamamoto T, Hotta Y. A case of childhood glaucoma with a combined partial monosomy 6p25 and partial trisomy 18p11 due to an unbalanced translocation. Ophthalmic Genet 2020; 41:175-182. [PMID: 32223580 DOI: 10.1080/13816810.2020.1744019] [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: 02/01/2023]
Abstract
Background: Chromosomal deletion involving the 6p25 region results in a clinically recognizable syndrome characterized by anterior eye chamber anomalies with risk of glaucoma and non-ocular malformations (6p25 deletion syndrome). We report a newborn infant case of childhood glaucoma with a combination of partial monosomy 6p25 and partial trisomy 18p11 due to an unbalanced translocation.Materials and methods: The patient was a 0-year-old girl. Both eyes showed aniridia and left eye Peters anomaly with multiple malformations. To identify the chromosomal aberrations in the patient with clinically suspected 6p25 deletion syndrome, we performed cytogenetic analysis (G-banding and multicolor fluorescent in-situ hybridization) and array-based comparative genomic hybridization (array-CGH) analysis.Results: Cytogenetic analyses revealed a derivative chromosome 6 with its distal short arm replaced by an extra copy of the short arm of chromosome 18. Array-CGH analysis detected a 4.6-Mb deletion at 6pter to 6p25.1 and 8.9-Mb duplication at 18pter to 18p11.22. To determine the breakpoint of the unbalanced rearrangement at the single-base level, we performed a long-range PCR for amplifying the junctional fragment of the translocation breakpoint. By sequencing the junctional fragment, we defined the unbalanced translocation as g.chr6:pter_4594783delinschr18:pter_8911541.Conclusions: A phenotype corresponding to combined monosomy 6p25 and trisomy 18p11 presented as childhood glaucoma associated with non-acquired (congenital) ocular anomalies consist of aniridia and Peters anomaly and other systemic malformations. To the best of our knowledge, this is the first report which demonstrated the breakpoint sequence of an unbalanced translocation in a Japanese infant with childhood glaucoma.
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Affiliation(s)
- Katsuhiro Hosono
- Department of Ophthalmology, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Kazuhide Kawase
- Department of Ophthalmology, Gifu University Graduate School of Medicine, Gifu, Japan
| | - Kentaro Kurata
- Department of Ophthalmology, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Yusuke Niimi
- Department of Ophthalmology, Gifu University Graduate School of Medicine, Gifu, Japan
| | - Hirotomo Saitsu
- Department of Biochemistry, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Shinsei Minoshima
- Department of Photomedical Genomics, Institute for Medical Photonics Research, Preeminent Medical Photonics Education & Research Center, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Hidenori Ohnishi
- Department of Pediatrics, Graduate School of Medicine, Gifu University, Gifu, Japan
| | - Takahiro Yamamoto
- Department of Pediatrics, Graduate School of Medicine, Gifu University, Gifu, Japan
| | - Akiko Hikoya
- Department of Ophthalmology, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Nobutaka Tachibana
- Department of Ophthalmology, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Toshiyuki Fukao
- Department of Pediatrics, Graduate School of Medicine, Gifu University, Gifu, Japan
| | - Tetsuya Yamamoto
- Department of Ophthalmology, Gifu University Graduate School of Medicine, Gifu, Japan
| | - Yoshihiro Hotta
- Department of Ophthalmology, Hamamatsu University School of Medicine, Hamamatsu, Japan
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Katagiri S, Iwasa M, Hayashi T, Hosono K, Yamashita T, Kuniyoshi K, Ueno S, Kondo M, Ueyama H, Ogita H, Shichida Y, Inagaki H, Kurahashi H, Kondo H, Ohji M, Hotta Y, Nakano T. Genotype determination of the OPN1LW/OPN1MW genes: novel disease-causing mechanisms in Japanese patients with blue cone monochromacy. Sci Rep 2018; 8:11507. [PMID: 30065301 PMCID: PMC6068165 DOI: 10.1038/s41598-018-29891-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 07/20/2018] [Indexed: 01/26/2023] Open
Abstract
Blue cone monochromacy (BCM) is characterized by loss of function of both OPN1LW (the first) and OPN1MW (the downstream) genes on the X chromosome. The purpose of this study was to investigate the first and downstream genes in the OPN1LW/OPN1MW array in four unrelated Japanese males with BCM. In Case 1, only one gene was present. Abnormalities were found in the promoter, which had a mixed unique profile of first and downstream gene promoters and a -71A > C substitution. As the promoter was active in the reporter assay, the cause of BCM remains unclear. In Case 2, the same novel mutation, M273K, was present in exon 5 of both genes in a two-gene array. The mutant pigments showed no absorbance at any of the wavelengths tested, suggesting that the mutation causes pigment dysfunction. Case 3 had a large deletion including the locus control region and entire first gene. Case 4 also had a large deletion involving exons 2-6 of the first gene. As an intact LCR was present upstream and one apparently normal downstream gene was present, BCM in Case 4 was not ascribed solely to the deletion. The deletions in Cases 3 and 4 were considered to have been caused by non-homologous recombination.
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Affiliation(s)
- Satoshi Katagiri
- Department of Ophthalmology, The Jikei University School of Medicine, Tokyo, Japan
| | - Maki Iwasa
- Department of Ophthalmology, Shiga University of Medical Science, Shiga, Japan
| | - Takaaki Hayashi
- Department of Ophthalmology, The Jikei University School of Medicine, Tokyo, Japan.
- Department of Ophthalmology, Katsushika Medical Center, The Jikei University School of Medicine, Tokyo, Japan.
| | - Katsuhiro Hosono
- Department of Ophthalmology, Hamamatsu University School of Medicine, Shizuoka, Japan
| | - Takahiro Yamashita
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - Kazuki Kuniyoshi
- Department of Ophthalmology, Kindai University Faculty of Medicine, Osaka, Japan
| | - Shinji Ueno
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, Aichi, Japan
| | - Mineo Kondo
- Department of Ophthalmology, Mie University Graduate School of Medicine, Mie, Japan
| | - Hisao Ueyama
- Department of Biochemistry and Molecular Biology, Shiga University of Medical Science, Shiga, Japan.
| | - Hisakazu Ogita
- Department of Biochemistry and Molecular Biology, Shiga University of Medical Science, Shiga, Japan
| | - Yoshinori Shichida
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - Hidehito Inagaki
- Division of Molecular Genetics, Institute for Comprehensive Medical Science, Fujita Health University, Aichi, Japan
| | - Hiroki Kurahashi
- Division of Molecular Genetics, Institute for Comprehensive Medical Science, Fujita Health University, Aichi, Japan
| | - Hiroyuki Kondo
- Department of Ophthalmology, University of Occupational and Environmental Health, Fukuoka, Japan
| | - Masahito Ohji
- Department of Ophthalmology, Shiga University of Medical Science, Shiga, Japan
| | - Yoshihiro Hotta
- Department of Ophthalmology, Hamamatsu University School of Medicine, Shizuoka, Japan
| | - Tadashi Nakano
- Department of Ophthalmology, The Jikei University School of Medicine, Tokyo, Japan
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