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Mihalich A, Cammarata G, Tremolada G, Manfredini E, Bianchi Marzoli S, Di Blasio AM. Genetic Characterization of 191 Probands with Inherited Retinal Dystrophy by Targeted NGS Analysis. Genes (Basel) 2024; 15:766. [PMID: 38927702 PMCID: PMC11203276 DOI: 10.3390/genes15060766] [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: 05/10/2024] [Revised: 06/04/2024] [Accepted: 06/08/2024] [Indexed: 06/28/2024] Open
Abstract
Inherited retinal diseases (IRDs) represent a frequent cause of blindness in children and adults. As a consequence of the phenotype and genotype heterogeneity of the disease, it is difficult to have a specific diagnosis without molecular testing. To date, over 340 genes and loci have been associated with IRDs. We present the molecular finding of 191 individuals with IRD, analyzed by targeted next-generation sequencing (NGS). For 67 of them, we performed a family segregation study, considering a total of 126 relatives. A total of 359 variants were identified, 44 of which were novel. Genetic diagnostic yield was 41%. However, after stratifying the patients according to their clinical suspicion, diagnostic yield was higher for well-characterized diseases such as Stargardt disease (STGD), at 65%, and for congenital stationary night blindness 2 (CSNB2), at 64%. Diagnostic yield was higher in the patient group where family segregation analysis was possible (68%) and it was higher in younger (55%) than in older patients (33%). The results of this analysis demonstrated that targeted NGS is an effective method for establishing a molecular genetic diagnosis of IRDs. Furthermore, this study underlines the importance of segregation studies to understand the role of genetic variants with unknow pathogenic role.
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Affiliation(s)
- Alessandra Mihalich
- Molecular Biology Laboratory, Istituto Auxologico Italiano IRCCS, 20145 Milan, Italy; (E.M.); (A.M.D.B.)
- Neuro-Ophthalmology Center and Electrophysiology Laboratory, Department of Ophthalmology, Istituto Auxologico Italiano IRCCS, 20145 Milan, Italy; (G.C.); (G.T.); (S.B.M.)
| | - Gabriella Cammarata
- Neuro-Ophthalmology Center and Electrophysiology Laboratory, Department of Ophthalmology, Istituto Auxologico Italiano IRCCS, 20145 Milan, Italy; (G.C.); (G.T.); (S.B.M.)
| | - Gemma Tremolada
- Neuro-Ophthalmology Center and Electrophysiology Laboratory, Department of Ophthalmology, Istituto Auxologico Italiano IRCCS, 20145 Milan, Italy; (G.C.); (G.T.); (S.B.M.)
| | - Emanuela Manfredini
- Molecular Biology Laboratory, Istituto Auxologico Italiano IRCCS, 20145 Milan, Italy; (E.M.); (A.M.D.B.)
| | - Stefania Bianchi Marzoli
- Neuro-Ophthalmology Center and Electrophysiology Laboratory, Department of Ophthalmology, Istituto Auxologico Italiano IRCCS, 20145 Milan, Italy; (G.C.); (G.T.); (S.B.M.)
| | - Anna Maria Di Blasio
- Molecular Biology Laboratory, Istituto Auxologico Italiano IRCCS, 20145 Milan, Italy; (E.M.); (A.M.D.B.)
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Wyględowska-Promieńska D, Świerczyńska M, Śpiewak D, Pojda-Wilczek D, Tronina A, Dorecka M, Smędowski A. Aland Island Eye Disease with Retinoschisis in the Clinical Spectrum of CACNA1F-Associated Retinopathy-A Case Report. Int J Mol Sci 2024; 25:2928. [PMID: 38474172 DOI: 10.3390/ijms25052928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Revised: 02/26/2024] [Accepted: 02/29/2024] [Indexed: 03/14/2024] Open
Abstract
Aland island eye disease (AIED), an incomplete form of X-linked congenital stationary night blindness (CSNB2A), and X-linked cone-rod dystrophy type 3 (CORDX3) display many overlapping clinical findings. They result from mutations in the CACNA1F gene encoding the α1F subunit of the Cav1.4 channel, which plays a key role in neurotransmission from rod and cone photoreceptors to bipolar cells. Case report: A 57-year-old Caucasian man who had suffered since his early childhood from nystagmus, nyctalopia, low visual acuity and high myopia in both eyes (OU) presented to expand the diagnostic process, because similar symptoms had occurred in his 2-month-old grandson. Additionally, the patient was diagnosed with protanomalous color vision deficiency, diffuse thinning, and moderate hypopigmentation of the retina. Optical coherence tomography of the macula revealed retinoschisis in the right eye and foveal hypoplasia in the left eye. Dark-adapted (DA) 3.0 flash full-field electroretinography (ffERG) amplitudes of a-waves were attenuated, and the amplitudes of b-waves were abolished, which resulted in a negative pattern of the ERG. Moreover, the light-adapted 3.0 and 3.0 flicker ffERG as well as the DA 0.01 ffERG were consistent with severely reduced responses OU. Genetic testing revealed a hemizygous form of a stop-gained mutation (c.4051C>T) in exon 35 of the CACNA1F gene. This pathogenic variant has so far been described in combination with a phenotype corresponding to CSNB2A and CORDX3. This report contributes to expanding the knowledge of the clinical spectrum of CACNA1F-related disease. Wide variability and the overlapping clinical manifestations observed within AIED and its allelic disorders may not be explained solely by the consequences of different mutations on proteins. The lack of distinct genotype-phenotype correlations indicates the presence of additional, not yet identified, disease-modifying factors.
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Affiliation(s)
- Dorota Wyględowska-Promieńska
- Department of Ophthalmology, Faculty of Medical Sciences in Katowice, Medical University of Silesia, 40-514 Katowice, Poland
- Kornel Gibiński University Clinical Center, 40-514 Katowice, Poland
| | - Marta Świerczyńska
- Department of Ophthalmology, Faculty of Medical Sciences in Katowice, Medical University of Silesia, 40-514 Katowice, Poland
- Kornel Gibiński University Clinical Center, 40-514 Katowice, Poland
| | - Dorota Śpiewak
- Kornel Gibiński University Clinical Center, 40-514 Katowice, Poland
| | - Dorota Pojda-Wilczek
- Department of Ophthalmology, Faculty of Medical Sciences in Katowice, Medical University of Silesia, 40-514 Katowice, Poland
- Kornel Gibiński University Clinical Center, 40-514 Katowice, Poland
| | - Agnieszka Tronina
- Kornel Gibiński University Clinical Center, 40-514 Katowice, Poland
- Department of Pediatric Ophthalmology, Faculty of Medical Sciences in Katowice, Medical University of Silesia, 40-514 Katowice, Poland
| | - Mariola Dorecka
- Department of Ophthalmology, Faculty of Medical Sciences in Katowice, Medical University of Silesia, 40-514 Katowice, Poland
- Kornel Gibiński University Clinical Center, 40-514 Katowice, Poland
| | - Adrian Smędowski
- Department of Ophthalmology, Faculty of Medical Sciences in Katowice, Medical University of Silesia, 40-514 Katowice, Poland
- Kornel Gibiński University Clinical Center, 40-514 Katowice, Poland
- GlaucoTech Co., 40-282 Katowice, Poland
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Sangermano R, Biswas P, Sullivan LS, Place EM, Borooah S, Straubhaar J, Pierce EA, Daiger SP, Bujakowska KM, Ayaggari R. Identification of a novel large multigene deletion and a frameshift indel in PDE6B as the underlying cause of early-onset recessive rod-cone degeneration. Cold Spring Harb Mol Case Stud 2022; 8:a006247. [PMID: 36376065 PMCID: PMC9808551 DOI: 10.1101/mcs.a006247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 11/02/2022] [Indexed: 11/15/2022] Open
Abstract
A family, with two affected identical twins with early-onset recessive inherited retinal degeneration, was analyzed to determine the underlying genetic cause of pathology. Exome sequencing revealed a rare and previously reported causative variant (c.1923_1969delinsTCTGGG; p.Asn643Glyfs*29) in the PDE6B gene in the affected twins and their unaffected father. Further investigation, using genome sequencing, identified a novel ∼7.5-kb deletion (Chr 4:670,405-677,862del) encompassing the ATP5ME gene, part of the 5' UTR of MYL5, and a 378-bp (Chr 4:670,405-670,782) region from the 3' UTR of PDE6B in the affected twins and their unaffected mother. Both variants segregated with disease in the family. Analysis of the relative expression of PDE6B, in peripheral blood cells, also revealed a significantly lower level of PDE6B transcript in affected siblings compared to a normal control. PDE6B is associated with recessive rod-cone degeneration and autosomal dominant congenital stationary night blindness. Ophthalmic evaluation of these patients showed night blindness, fundus abnormalities, and peripheral vision loss, which are consistent with PDE6B-associated recessive retinal degeneration. These findings suggest that the loss of PDE6B transcript resulting from the compound heterozygous pathogenic variants is the underlying cause of recessive rod-cone degeneration in the study family.
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Affiliation(s)
- Riccardo Sangermano
- Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts 02114, USA
| | - Pooja Biswas
- Shiley Eye Institute, University of California San Diego, La Jolla, California 92093, USA
| | - Lori S Sullivan
- Human Genetics Center, School of Public Health, University of Texas Health Science Center at Houston, Houston, Texas 77030, USA
| | - Emily M Place
- Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts 02114, USA
| | - Shyamanga Borooah
- Shiley Eye Institute, University of California San Diego, La Jolla, California 92093, USA
| | - Juerg Straubhaar
- Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts 02114, USA
| | - Eric A Pierce
- Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts 02114, USA
| | - Stephen P Daiger
- Human Genetics Center, School of Public Health, University of Texas Health Science Center at Houston, Houston, Texas 77030, USA
| | - Kinga M Bujakowska
- Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts 02114, USA
| | - Radha Ayaggari
- Shiley Eye Institute, University of California San Diego, La Jolla, California 92093, USA
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Du M, Li Y, Zheng P, Zhong L, Zhao W, Zhang Y, Gu H, Li X, Liu Z. Identification of a novel CACNA1F mutation in a Chinese family with CORDX3. Mol Genet Genomic Med 2022; 10:e2060. [PMID: 36165086 PMCID: PMC9651601 DOI: 10.1002/mgg3.2060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 08/16/2022] [Accepted: 09/08/2022] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND X-linked cone-rod dystrophy (CORDX) is one form of inherited retinal disorders (IRDs) characterized by progressive dysfunction of photoreceptor. Three types of CORDX were reported and CACNA1F gene defect can cause CORDX3. The aim of this study was to investigate the pathogenic variant in a Chinese family with IRD. METHODS The two affected subjects including the proband and his elder sister underwent ophthalmic examinations. Whole exome sequencing (WES) was performed in the proband at first, then co-segregation analysis was performed in the family by Sanger sequencing. Minigene approach was used to verify the effect of the mutation on the splicing of CACNA1F. X-chromosomal inactivation assay was performed to evaluate the inactivation patterns of the female carriers. RESULTS The ophthalmic examination results of the proband fit the clinical description of CORDX3, and the female patient presented with only mild symptoms due to mildly skewed X-chromosomal inactivation (ratio 67: 33). Molecular genetic testing identified a novel splice-site mutation c.3847-2A > G in CACNA1F (NM_005183.4) gene in the patients, which inherited from their asymptomatic mother. Minigene approach confirmed that c.3847-2A > G could affect the splicing of CACNA1F. CONCLUSION Our study identified a novel splice-site mutation in the CACNA1F gene, which expanded the mutational spectrum of CACNA1F-releated diseases and demonstrated the importance of combining clinical and genetic testing in the diagnosis of IRDs.
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Affiliation(s)
- Meng Du
- Hebei Provincial Key Laboratory of Basic Medicine for DiabetesThe Shijiazhuang Second HospitalShijiazhuangChina,Shijiazhuang Technology Innovation Center of Precision Medicine for DiabetesThe Shijiazhuang Second HospitalShijiazhuangChina
| | - Yang Li
- Hebei Provincial Key Laboratory of Basic Medicine for DiabetesThe Shijiazhuang Second HospitalShijiazhuangChina,Shijiazhuang Technology Innovation Center of Precision Medicine for DiabetesThe Shijiazhuang Second HospitalShijiazhuangChina
| | - Panpan Zheng
- Hebei Provincial Key Laboratory of Basic Medicine for DiabetesThe Shijiazhuang Second HospitalShijiazhuangChina,Shijiazhuang Technology Innovation Center of Precision Medicine for DiabetesThe Shijiazhuang Second HospitalShijiazhuangChina
| | - Liang Zhong
- Hebei Provincial Key Laboratory of Basic Medicine for DiabetesThe Shijiazhuang Second HospitalShijiazhuangChina,Shijiazhuang Technology Innovation Center of Precision Medicine for DiabetesThe Shijiazhuang Second HospitalShijiazhuangChina
| | - Weili Zhao
- Hebei Provincial Key Laboratory of Basic Medicine for DiabetesThe Shijiazhuang Second HospitalShijiazhuangChina,Shijiazhuang Technology Innovation Center of Precision Medicine for DiabetesThe Shijiazhuang Second HospitalShijiazhuangChina
| | - Yuxin Zhang
- Hebei Provincial Key Laboratory of Basic Medicine for DiabetesThe Shijiazhuang Second HospitalShijiazhuangChina,Shijiazhuang Technology Innovation Center of Precision Medicine for DiabetesThe Shijiazhuang Second HospitalShijiazhuangChina
| | - Haiyan Gu
- Hebei Provincial Key Laboratory of Basic Medicine for DiabetesThe Shijiazhuang Second HospitalShijiazhuangChina,Shijiazhuang Technology Innovation Center of Precision Medicine for DiabetesThe Shijiazhuang Second HospitalShijiazhuangChina
| | - Xue Li
- Medical Service Department, MyGenostics lnc.BeijingChina
| | - Zanchao Liu
- Hebei Provincial Key Laboratory of Basic Medicine for DiabetesThe Shijiazhuang Second HospitalShijiazhuangChina,Shijiazhuang Technology Innovation Center of Precision Medicine for DiabetesThe Shijiazhuang Second HospitalShijiazhuangChina
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