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Sundaresan Y, Rivera A, Obolensky A, Gopalakrishnan P, Ohayon Hadad H, Shemesh A, Khateb S, Ross M, Ofri R, Durst S, Newman H, Leibu R, Soudry S, Zur D, Ben-Yosef T, Banin E, Sharon D. Genetic and Clinical Analyses of the KIZ-c.226C>T Variant Resulting in a Dual Mutational Mechanism. Genes (Basel) 2024; 15:804. [PMID: 38927740 PMCID: PMC11202946 DOI: 10.3390/genes15060804] [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: 05/25/2024] [Revised: 06/11/2024] [Accepted: 06/17/2024] [Indexed: 06/28/2024] Open
Abstract
Retinitis pigmentosa (RP) is a heterogeneous inherited retinal disorder. Mutations in KIZ cause autosomal recessive (AR) RP. We aimed to characterize the genotype, expression pattern, and phenotype in a large cohort of KIZ cases. Sanger and whole exome sequencing were used to identify the KIZ variants. Medical records were reviewed and analyzed. Thirty-one patients with biallelic KIZ mutations were identified: 28 homozygous for c.226C>T (p.R76*), 2 compound heterozygous for p.R76* and c.3G>A (p.M1?), and one homozygous for c.247C>T (p.R83*). c.226C>T is a founder mutation among patients of Jewish descent. The clinical parameters were less severe in KIZ compared to DHDDS and FAM161A cases. RT-PCR analysis in fibroblast cells revealed the presence of four different transcripts in both WT and mutant samples with a lower percentage of the WT transcript in patients. Sequence analysis identified an exonic sequence enhancer (ESE) that includes the c.226 position which is affected by the mutation. KIZ mutations are an uncommon cause of IRD worldwide but are not rare among Ashkenazi Jews. Our data indicate that p.R76* affect an ESE which in turn results in the pronounced skipping of exon 3. Therefore, RNA-based therapies might show low efficacy since the mutant transcripts are spliced.
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Affiliation(s)
- Yogapriya Sundaresan
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel; (Y.S.); (A.R.); (P.G.); (E.B.)
| | - Antonio Rivera
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel; (Y.S.); (A.R.); (P.G.); (E.B.)
| | - Alexey Obolensky
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel; (Y.S.); (A.R.); (P.G.); (E.B.)
| | - Prakadeeswari Gopalakrishnan
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel; (Y.S.); (A.R.); (P.G.); (E.B.)
| | - Hanit Ohayon Hadad
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel; (Y.S.); (A.R.); (P.G.); (E.B.)
| | - Aya Shemesh
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel; (Y.S.); (A.R.); (P.G.); (E.B.)
| | - Samer Khateb
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel; (Y.S.); (A.R.); (P.G.); (E.B.)
| | - Maya Ross
- Koret School of Veterinary Medicine, The Hebrew University of Jerusalem, Rehovot 76100, Israel
| | - Ron Ofri
- Koret School of Veterinary Medicine, The Hebrew University of Jerusalem, Rehovot 76100, Israel
| | - Sharon Durst
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel; (Y.S.); (A.R.); (P.G.); (E.B.)
| | - Hadas Newman
- Ophthalmology Division, Tel Aviv Sourasky Medical Center, Affiliated to Faculty of Medical & Health Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Rina Leibu
- Department of Ophthalmology, Rambam Health Care Center, Haifa 31096, Israel
| | - Shiri Soudry
- Department of Ophthalmology, Rabin Medical Center, Petah Tikva 49100, Israel
| | - Dinah Zur
- Ophthalmology Division, Tel Aviv Sourasky Medical Center, Affiliated to Faculty of Medical & Health Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Tamar Ben-Yosef
- The Ruth & Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa 31096, Israel
| | - Eyal Banin
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel; (Y.S.); (A.R.); (P.G.); (E.B.)
| | - Dror Sharon
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel; (Y.S.); (A.R.); (P.G.); (E.B.)
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Shalom S, Hanany M, Eilat A, Chowers I, Ben-Yosef T, Khateb S, Banin E, Sharon D. Simultaneous Detection of Common Founder Mutations Using a Cost-Effective Deep Sequencing Panel. Genes (Basel) 2024; 15:646. [PMID: 38790275 PMCID: PMC11120920 DOI: 10.3390/genes15050646] [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: 04/15/2024] [Revised: 05/13/2024] [Accepted: 05/16/2024] [Indexed: 05/26/2024] Open
Abstract
Inherited retinal diseases (IRDs) are a clinically and genetically heterogeneous group of diseases which cause visual loss due to Mendelian mutations in over 250 genes, making genetic diagnosis challenging and time-consuming. Here, we developed a new tool, CDIP (Cost-effective Deep-sequencing IRD Panel) in which a simultaneous sequencing of common mutations is performed. CDIP is based on simultaneous amplification of 47 amplicons harboring common mutations followed by next-generation sequencing (NGS). Following five rounds of calibration of NGS-based steps, CDIP was used in 740 IRD samples. The analysis revealed 151 mutations in 131 index cases. In 54 (7%) of these cases, CDIP identified the genetic cause of disease (the remaining were single-heterozygous recessive mutations). These include a patient that was clinically diagnosed with retinoschisis and found to be homozygous for NR2E3-c.932G>A (p.R311Q), and a patient with RP who is hemizygous for an RPGR variant, c.292C>A (p.H98N), which was not included in the analysis but is located in proximity to one of these mutations. CDIP is a cost-effective deep sequencing panel for simultaneous detection of common founder mutations. This protocol can be implemented for additional populations as well as additional inherited diseases, and mainly in populations with strong founder effects.
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Affiliation(s)
- Sapir Shalom
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel; (S.S.); (M.H.); (A.E.); (I.C.); (S.K.); (E.B.)
- Department of Military Medicine and “Tzameret”, Faculty of Medicine, Hebrew University of Jerusalem and Medical Corps, Israel Defense Forces, Jerusalem 91120, Israel
| | - Mor Hanany
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel; (S.S.); (M.H.); (A.E.); (I.C.); (S.K.); (E.B.)
| | - Avital Eilat
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel; (S.S.); (M.H.); (A.E.); (I.C.); (S.K.); (E.B.)
| | - Itay Chowers
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel; (S.S.); (M.H.); (A.E.); (I.C.); (S.K.); (E.B.)
| | - Tamar Ben-Yosef
- Rappaport Faculty of Medicine, Technion—Israel Institute of Technology, Haifa 3109601, Israel;
| | - Samer Khateb
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel; (S.S.); (M.H.); (A.E.); (I.C.); (S.K.); (E.B.)
| | - Eyal Banin
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel; (S.S.); (M.H.); (A.E.); (I.C.); (S.K.); (E.B.)
| | - Dror Sharon
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel; (S.S.); (M.H.); (A.E.); (I.C.); (S.K.); (E.B.)
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Monson E, Cideciyan AV, Roman AJ, Sumaroka A, Swider M, Wu V, Viarbitskaya I, Jacobson SG, Fliesler SJ, Pittler SJ. Inherited Retinal Degeneration Caused by Dehydrodolichyl Diphosphate Synthase Mutation-Effect of an ALG6 Modifier Variant. Int J Mol Sci 2024; 25:1004. [PMID: 38256083 PMCID: PMC10816542 DOI: 10.3390/ijms25021004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 01/04/2024] [Accepted: 01/08/2024] [Indexed: 01/24/2024] Open
Abstract
Modern advances in disease genetics have uncovered numerous modifier genes that play a role in the severity of disease expression. One such class of genetic conditions is known as inherited retinal degenerations (IRDs), a collection of retinal degenerative disorders caused by mutations in over 300 genes. A single missense mutation (K42E) in the gene encoding the enzyme dehydrodolichyl diphosphate synthase (DHDDS), which is required for protein N-glycosylation in all cells and tissues, causes DHDDS-IRD (retinitis pigmentosa type 59 (RP59; OMIM #613861)). Apart from a retinal phenotype, however, DHDDS-IRD is surprisingly non-syndromic (i.e., without any systemic manifestations). To explore disease pathology, we selected five glycosylation-related genes for analysis that are suggested to have disease modifier variants. These genes encode glycosyltransferases (ALG6, ALG8), an ER resident protein (DDOST), a high-mannose oligosaccharyl transferase (MPDU1), and a protein N-glycosylation regulatory protein (TNKS). DNA samples from 11 confirmed DHDDS (K42E)-IRD patients were sequenced at the site of each candidate genetic modifier. Quantitative measures of retinal structure and function were performed across five decades of life by evaluating foveal photoreceptor thickness, visual acuity, foveal sensitivity, macular and extramacular rod sensitivity, and kinetic visual field extent. The ALG6 variant, (F304S), was correlated with greater macular cone disease severity and less peripheral rod disease severity. Thus, modifier gene polymorphisms may account for a significant portion of phenotypic variation observed in human genetic disease. However, the consequences of the polymorphisms may be counterintuitively complex in terms of rod and cone populations affected in different regions of the retina.
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Affiliation(s)
- Elisha Monson
- Department of Optometry and Vision Science, University of Alabama at Birmingham, Birmingham, AL 35294, USA;
| | - Artur V. Cideciyan
- Center for Hereditary Retinal Degenerations, Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (A.J.R.); (A.S.); (M.S.); (V.W.); (I.V.)
| | - Alejandro J. Roman
- Center for Hereditary Retinal Degenerations, Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (A.J.R.); (A.S.); (M.S.); (V.W.); (I.V.)
| | - Alexander Sumaroka
- Center for Hereditary Retinal Degenerations, Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (A.J.R.); (A.S.); (M.S.); (V.W.); (I.V.)
| | - Malgorzata Swider
- Center for Hereditary Retinal Degenerations, Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (A.J.R.); (A.S.); (M.S.); (V.W.); (I.V.)
| | - Vivian Wu
- Center for Hereditary Retinal Degenerations, Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (A.J.R.); (A.S.); (M.S.); (V.W.); (I.V.)
| | - Iryna Viarbitskaya
- Center for Hereditary Retinal Degenerations, Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (A.J.R.); (A.S.); (M.S.); (V.W.); (I.V.)
| | - Samuel G. Jacobson
- Center for Hereditary Retinal Degenerations, Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (A.J.R.); (A.S.); (M.S.); (V.W.); (I.V.)
| | - Steven J. Fliesler
- Departments of Ophthalmology and Biochemistry, and Neuroscience Graduate Program, Jacobs School of Medicine and Biomedical Sciences, State University of New York—University at Buffalo, Buffalo, NY 14203, USA;
- Research Service, VA Western NY Healthcare System, Buffalo, NY 14215, USA
| | - Steven J. Pittler
- Department of Optometry and Vision Science, University of Alabama at Birmingham, Birmingham, AL 35294, USA;
- Vision Science Research Center, School of Optometry, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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Yu M, Zhang M, Chen Q, Huang T, Gan R, Yan X. A novel compound heterozygous PEX1 variant in Heimler syndrome. Exp Eye Res 2023; 237:109688. [PMID: 37871882 DOI: 10.1016/j.exer.2023.109688] [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: 07/06/2023] [Revised: 10/14/2023] [Accepted: 10/20/2023] [Indexed: 10/25/2023]
Abstract
Heimler syndrome (HS) is a rare autosomal recessive hereditary disease that is caused by biallelic variants in peroxisomal biogenic factor 1 gene (PEX1), peroxisomal biogenic factor 6 gene (PEX6) or peroxisomal biogenic factor 26 gene (PEX26), resulting in intracellular peroxisomal dysfunction (PBDs). We report a patient with HS with a new compound heterozygous PEX1 variant. Exon sequencing was used to screen pathologic variants in the patient. Retinal characteristics and serum metabolome alterations were evaluated. Scanning laser ophthalmoscope showed a large area of retinal choroidal atrophy at the posterior pole of the retina, with scattered patchy subretinal pigmentation. Optical coherence tomography showed fovea atrophy accompanied by retinal retinoschisis in the right eye and macular retinoschisis and edema in the left eye. The electroretinogram showed obviously reduced amplitudes of a-waves and b-waves under photopic and scotopic conditions in both eyes. Visual field tests showed a reduced central visual field in both eyes. Exon sequencing identified the compound heterozygous variant including c.2966T > C and c.1670+1G > T of the PEX1 gene, with the latter being novel. Nontargeted determination of total lipid metabolites and targeted determination of medium- and long-chain fatty acids in the serum of the patient and his healthy sibling were tested. This study identified a new compound heterozygous PEX1 variant, expanding our understanding of phenotypes in HS.
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Affiliation(s)
- Mingyu Yu
- Shenzhen Eye Hospital, Jinan University, Shenzhen Eye Institute, Shenzhen, China
| | - Min Zhang
- School of Medicine, Anhui University of Science and Technology, Huainan, China
| | - Qingshan Chen
- Shenzhen Eye Hospital, Jinan University, Shenzhen Eye Institute, Shenzhen, China
| | - Tao Huang
- Shenzhen Eye Hospital, Jinan University, Shenzhen Eye Institute, Shenzhen, China
| | - Run Gan
- Shenzhen Eye Hospital, Jinan University, Shenzhen Eye Institute, Shenzhen, China
| | - Xiaohe Yan
- Shenzhen Eye Hospital, Jinan University, Shenzhen Eye Institute, Shenzhen, China.
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Chan CM, Tan TE, Jain K, Bylstra Y, Mathur RS, Tang RWC, Lee BJH, Jamuar SS, Kam S, Vithana EN, Lim WK, Fenner BJ. RETINITIS PIGMENTOSA ASSOCIATED WITH THE EYS C2139Y VARIANT : An Important Cause of Blindness in East Asian Populations. Retina 2023; 43:1788-1796. [PMID: 37418643 DOI: 10.1097/iae.0000000000003874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/09/2023]
Abstract
PURPOSE The study aimed to describe the phenotypic features of retinitis pigmentosa (RP) associated with the previously described EYS C2139Y variant in Singaporeans and establish the importance of this variant as a prevalent cause of RP among East Asians. METHODS A clinical phenotyping and exome-sequencing study was conducted on consecutive patients with nonsyndromic RP. Epidemiological analysis was performed using Singaporean and global population-based genetic data. RESULTS A study of 150 consecutive unrelated individuals with nonsyndromic RP found that 87 (58%) of cases had plausible genotypes. A previously described missense variant in the EYS gene, 6416G>A (C2139Y), occurred heterozygously or homozygously in 17 of 150 families (11.3%), all with autosomal recessive RP. Symptom onset in EYS C2139Y-related RP ranged from 6 to 45 years, with visual acuity ranging from 20/20 at 21 years to no light perception by 48 years. C2139Y-related RP had typical findings, including sectoral RP in cases with EYS E2703X in trans . The median age at presentation was 45 years and visual fields declined to less than 20° (Goldmann V4e isopter) by age 65 years. Intereye correlation for visual acuity, fields, and ellipsoid band width was high (r 2 = 0.77-0.95). Carrier prevalence was 0.66% (allele frequency of 0.33%) in Singaporean Chinese and 0.34% in East Asians, suggesting a global disease burden exceeding 10,000 individuals. CONCLUSION The EYS C2139Y variant is common in Singaporean RP patients and other ethnic Chinese populations. Targeted molecular therapy for this single variant could potentially treat a significant proportion of RP cases worldwide.
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Affiliation(s)
- Choi Mun Chan
- Singapore National Eye Centre, Singapore Eye Research Institute, and the Ophthalmology and Visual Sciences Academic Clinical Program (EYE ACP), Duke-NUS Graduate Medical School, Singapore
| | - Tien-En Tan
- Singapore National Eye Centre, Singapore Eye Research Institute, and the Ophthalmology and Visual Sciences Academic Clinical Program (EYE ACP), Duke-NUS Graduate Medical School, Singapore
| | - Kanika Jain
- Genome Institute of Singapore, Agency for Science, Technology and Research (A*STAR), Singapore
| | - Yasmin Bylstra
- SingHealth Duke-NUS Institute of Precision Medicine (PRISM), Singapore
| | - Ranjana S Mathur
- Singapore National Eye Centre, Singapore Eye Research Institute, and the Ophthalmology and Visual Sciences Academic Clinical Program (EYE ACP), Duke-NUS Graduate Medical School, Singapore
| | - Rachael W C Tang
- Singapore National Eye Centre, Singapore Eye Research Institute, and the Ophthalmology and Visual Sciences Academic Clinical Program (EYE ACP), Duke-NUS Graduate Medical School, Singapore
| | - Brian J H Lee
- Lee Kong Chian Medical School, Nanyang Technological University, Singapore; and
| | - Saumya S Jamuar
- Department of Paediatrics, KK Women's and Children's Hospital and the SingHealth Duke-NUS Genomic Medicine Center, Singapore
| | - Sylvia Kam
- Department of Paediatrics, KK Women's and Children's Hospital and the SingHealth Duke-NUS Genomic Medicine Center, Singapore
| | - Eranga N Vithana
- Singapore National Eye Centre, Singapore Eye Research Institute, and the Ophthalmology and Visual Sciences Academic Clinical Program (EYE ACP), Duke-NUS Graduate Medical School, Singapore
| | - Weng Khong Lim
- SingHealth Duke-NUS Institute of Precision Medicine (PRISM), Singapore
| | - Beau J Fenner
- Singapore National Eye Centre, Singapore Eye Research Institute, and the Ophthalmology and Visual Sciences Academic Clinical Program (EYE ACP), Duke-NUS Graduate Medical School, Singapore
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Nguyen MN, Chakraborty D, Rao SR, Onysk A, Radkiewicz M, Surmacz L, Swiezewska E, Soubeyrand E, Akhtar TA, Kraft TW, Sherry DM, Fliesler SJ, Pittler SJ. A Dhdds K42E knock-in RP59 mouse model shows inner retina pathology and defective synaptic transmission. Cell Death Dis 2023; 14:420. [PMID: 37443173 PMCID: PMC10345138 DOI: 10.1038/s41419-023-05936-4] [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: 09/11/2022] [Revised: 06/07/2023] [Accepted: 06/29/2023] [Indexed: 07/15/2023]
Abstract
Retinitis pigmentosa (RP) defines a group of hereditary progressive rod-cone degenerations that exhibit a common phenotype caused by variants in over 70 genes. While most variants in the dehydrodolichyl diphosphate synthase (DHDDS) gene result in syndromic abnormalities, some variants cause non-syndromic RP (RP59). DHDDS encodes one subunit of the enzyme cis-prenyltransferase (CPT), which is required for the synthesis of dolichol (Dol), that is a necessary protein glycosylation cofactor. We previously reported the creation and initial characterization of a knock-in (KI) mouse model harboring the most prevalent RP59-associated DHDDS variant (K42E) to understand how defects in DHDDS lead to retina-specific pathology. This model exhibited no profound retinal degeneration, nor protein N-glycosylation defects. Here, we report that the Dol isoprenylogue species in retina, liver, and brain of the K42E mouse model are statistically shorter than in the corresponding tissues of age-matched controls, as reported in blood and urine of RP59 patients. Retinal transcriptome analysis demonstrated elevation of many genes encoding proteins involved in synaptogenesis and synaptic function. Quantitative retinal cell layer thickness measurements demonstrated a significant reduction in the inner nuclear layer (INL) and total retinal thickness (TRT) beginning at postnatal (PN) ∼2 months, progressively increasing to PN 18-mo. Histological analysis revealed cell loss in the INL, outer plexiform layer (OPL) disruption, and ectopic localization of outer nuclear layer (ONL) nuclei into the OPL of K42E mutant retinas, relative to controls. Electroretinograms (ERGs) of mutant mice exhibited reduced b-wave amplitudes beginning at PN 1-mo, progressively declining through PN 18-mo, without appreciable a-wave attenuation, relative to controls. Our results suggest that the underlying cause of DHDDS K42E variant driven RP59 retinal pathology is defective synaptic transmission from outer to inner retina.
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Affiliation(s)
- Mai N Nguyen
- Department of Optometry and Vision Science, Vision Science Research Center, School of Optometry, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Dibyendu Chakraborty
- Department of Optometry and Vision Science, Vision Science Research Center, School of Optometry, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Sriganesh Ramachandra Rao
- Research Service, VA Western New York Healthcare System, Buffalo, NY, 14215, USA
- Departments of Ophthalmology and Biochemistry and Neuroscience Graduate Program, Jacobs School of Medicine and Biomedical Sciences, The State University of New York, University at Buffalo, Buffalo, NY, 14203, USA
| | - Agnieszka Onysk
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, 02106, Poland
| | - Mariusz Radkiewicz
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, 02106, Poland
| | - Liliana Surmacz
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, 02106, Poland
| | - Ewa Swiezewska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, 02106, Poland
| | - Eric Soubeyrand
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, N1G2W1, Canada
| | - Tariq A Akhtar
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, N1G2W1, Canada
| | - Timothy W Kraft
- Department of Optometry and Vision Science, Vision Science Research Center, School of Optometry, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - David M Sherry
- Departments of Cell Biology, Neurosurgery, and Pharmaceutical Sciences, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
| | - Steven J Fliesler
- Research Service, VA Western New York Healthcare System, Buffalo, NY, 14215, USA
- Departments of Ophthalmology and Biochemistry and Neuroscience Graduate Program, Jacobs School of Medicine and Biomedical Sciences, The State University of New York, University at Buffalo, Buffalo, NY, 14203, USA
| | - Steven J Pittler
- Department of Optometry and Vision Science, Vision Science Research Center, School of Optometry, University of Alabama at Birmingham, Birmingham, AL, 35294, USA.
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7
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Toms M, Ward N, Moosajee M. Nuclear Receptor Subfamily 2 Group E Member 3 (NR2E3): Role in Retinal Development and Disease. Genes (Basel) 2023; 14:1325. [PMID: 37510230 PMCID: PMC10379133 DOI: 10.3390/genes14071325] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 06/11/2023] [Accepted: 06/19/2023] [Indexed: 07/30/2023] Open
Abstract
NR2E3 is a nuclear hormone receptor gene required for the correct development of the retinal rod photoreceptors. Expression of NR2E3 protein in rod cell precursors suppresses cone-specific gene expression and, in concert with other transcription factors including NRL, activates the expression of rod-specific genes. Pathogenic variants involving NR2E3 cause a spectrum of retinopathies, including enhanced S-cone syndrome, Goldmann-Favre syndrome, retinitis pigmentosa, and clumped pigmentary retinal degeneration, with limited evidence of genotype-phenotype correlations. A common feature of NR2E3-related disease is an abnormally high number of cone photoreceptors that are sensitive to short wavelength light, the S-cones. This characteristic has been supported by mouse studies, which have also revealed that loss of Nr2e3 function causes photoreceptors to develop as cells that are intermediate between rods and cones. While there is currently no available cure for NR2E3-related retinopathies, there are a number of emerging therapeutic strategies under investigation, including the use of viral gene therapy and gene editing, that have shown promise for the future treatment of patients with NR2E3 variants and other inherited retinal diseases. This review provides a detailed overview of the current understanding of the role of NR2E3 in normal development and disease, and the associated clinical phenotypes, animal models, and therapeutic studies.
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Affiliation(s)
- Maria Toms
- Development, Ageing and Disease, UCL Institute of Ophthalmology, London EC1V 9EL, UK
- Ocular Genomics and Therapeutics, The Francis Crick Institute, London NW1 1AT, UK
| | - Natasha Ward
- Development, Ageing and Disease, UCL Institute of Ophthalmology, London EC1V 9EL, UK
| | - Mariya Moosajee
- Development, Ageing and Disease, UCL Institute of Ophthalmology, London EC1V 9EL, UK
- Ocular Genomics and Therapeutics, The Francis Crick Institute, London NW1 1AT, UK
- Department of Genetics, Moorfields Eye Hospital NHS Foundation Trust, London EC1V 2PD, UK
- Department of Ophthalmology, Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK
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Lv T, Fu JX, Liu XY, Tang R, Yang GL. Case analysis of epilepsy, neurodevelopmental disorder, and motor disorders associated with mutations in the dehydrodolichyl diphosphate synthase gene. Seizure 2023; 110:126-135. [PMID: 37356182 DOI: 10.1016/j.seizure.2023.06.006] [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: 10/24/2022] [Revised: 06/06/2023] [Accepted: 06/08/2023] [Indexed: 06/27/2023] Open
Abstract
The objective of this study is to analyze the role of dehydrodolichyl diphosphate synthase (DHDDS), a crucial enzyme in the mevalonate pathway, and its encoded mutations in the onset of developmental delay and seizures, with or without movement abnormalities. Its genotype-phenotype characteristics are still inconclusive. We analyzed the clinical characteristics of epilepsy, and neurodevelopmental and motor disorders related to DHDDS gene mutations and report the genotype-phenotype characteristics of a child with epilepsy caused by DHDDS gene mutation, providing a summary and a statistical analysis of epilepsy cases associated with DHDDS gene mutation up until February 2022. METHODS Using "DHDDS; epilepsy; neurodevelopmental disorder" as the keywords, the literature relevant to DHDDS gene mutations up until February 2022 was reviewed. A total of 25 cases were retrieved, among which 21 cases with complete data were included in the chi-squared test. The clinical characteristics of DHDDS gene-related cases were summarized and analyzed. RESULTS The onset of epilepsy caused by mutations of the DHDDS gene typically occurs during infancy. Predominantly, the mutation occurs in the locus of c.632G>A p.R211Q. Myoclonus is frequently the initial manifestation of epilepsy; it frequently coexists with neurodevelopmental disorder and intellectual disability, and patients have no specific type of motor disorder. Cranial magnetic resonance imaging (MRI) reveals no abnormalities, whereas electroencephalogram (EEG) frequently exhibits abnormalities. Valproic acid (VPA) yields good curative effects. CONCLUSION Mutations in the DHDDS gene are associated with congenital glycosylation disorder, autosomal recessive retinitis pigmentosa, and epilepsy. According to statistical analysis using the chi-squared test, for pediatric patients with mutations in this gene locus, most of the epilepsy types are myoclonic epilepsies with intellectual disability and neurodevelopmental disorders. They have normal brain MRIs and abnormal EEGs. VPA produces beneficial therapeutic results and the differences are all statistically significant. The current diagnosis still relies on next-generation sequencing or whole-exome sequencing.
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Affiliation(s)
- Ting Lv
- Department of Pediatrics, The Affiliated Hospital of Inner Mongolia Medical University, No. 1 North Channel Road, Inner Mongolia, Hohhot 010050, China
| | - Jun-Xian Fu
- Department of Pediatrics, The Affiliated Hospital of Inner Mongolia Medical University, No. 1 North Channel Road, Inner Mongolia, Hohhot 010050, China
| | - Xiao-Yang Liu
- Department of Pediatrics, The Affiliated Hospital of Inner Mongolia Medical University, No. 1 North Channel Road, Inner Mongolia, Hohhot 010050, China
| | - Rong Tang
- Department of Pediatrics, The Affiliated Hospital of Inner Mongolia Medical University, No. 1 North Channel Road, Inner Mongolia, Hohhot 010050, China
| | - Guang-Lu Yang
- Department of Pediatrics, The Affiliated Hospital of Inner Mongolia Medical University, No. 1 North Channel Road, Inner Mongolia, Hohhot 010050, China; Inner Mongolia Science and Technology Department, Inner Mongolia Autonomous Region nervous system disease clinical medical research center, No. 1 North Road, Huimin District, Hohhot 010050, China.
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9
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Genetic characteristics of suspected retinitis pigmentosa in a cohort of Chinese patients. Gene 2023; 853:147087. [PMID: 36464167 DOI: 10.1016/j.gene.2022.147087] [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: 05/23/2022] [Revised: 11/22/2022] [Accepted: 11/28/2022] [Indexed: 12/03/2022]
Abstract
The study aimed to screen for the causative variants in Chinese patients with suspected retinitis pigmentosa (RP). A cohort of 75 unrelated Chinese patients with a clinical diagnosis of RP and their available family members were enrolled in this study. Genomic DNA of all subjects was extracted and whole-exome sequencing (WES) was applied. Candidate variants were identified, and minigene assays were conducted to evaluate the pathogenicity of novel splicing variants. Totally, the diagnostic yield was 44 % (33/75) and 16 novel variants that had not been reported previously were found. Among the genetically solved 33 cases, 31 patients were identified as carrying causative variants of RP and 2 patients carried pathogenic variants implicated in other retinal diseases. USH2A, CYP4V2, and RPGR were the most common causative genes, accounting for about half of the genetically solved cases. Moreover, minigene assays validated that the novel splicing variants were detrimental. Additionally, 9 patients carried a single deleterious heterozygous variant in 6 genes with autosomal recessive hereditary patterns, and no corresponding copy number variants (CNVs) was detected. The findings of this study revealed the genetic landscape of RP in China and provided guidance for clinicians.
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10
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Rao SR, Pittler SJ, Fliesler SJ. Perspectives on Retinal Dolichol Metabolism, and Visual Deficits in Dolichol Metabolism-Associated Inherited Disorders. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1415:449-456. [PMID: 37440071 DOI: 10.1007/978-3-031-27681-1_66] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/14/2023]
Abstract
De novo synthesis of dolichol (Dol) and dolichyl phosphate (Dol-P) is essential for protein glycosylation. Herein, we provide a brief overview of Dol and Dol-P synthesis and the maintenance of their cellular content. Retinal Dol metabolism and the requirement of Dol-linked oligosaccharide synthesis in the neural retina also are discussed. There are recently discovered and an emerging class of rare congenital disorders that affect Dol metabolism, involving the genes DHDDS, NUS1, SRD5A3, and DOLK. Further understanding of these congenital disorders is evolving, based upon studies utilizing yeast and murine models, as well as clinical reports of these rare disorders. We summarize the known visual deficits associated with Dol metabolism disorders, and identify the need for generation and characterization of suitable animal models of these disorders to elucidate the underlying molecular and cellular mechanisms of the associated retinopathies.
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Affiliation(s)
- Sriganesh Ramachandra Rao
- Departments of Ophthalmology and Biochemistry, and Neuroscience Graduate Program, Jacobs School of Medicine and Biomedical Sciences, State University of New York, Buffalo, NY, USA
- Research Service, VA Western NY Healthcare System, Buffalo, NY, USA
| | - Steven J Pittler
- Department of Optometry and Vision Science, Vision Science Research Center, School of Optometry, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Steven J Fliesler
- Departments of Ophthalmology and Biochemistry, and Neuroscience Graduate Program, Jacobs School of Medicine and Biomedical Sciences, State University of New York, Buffalo, NY, USA.
- Research Service, VA Western NY Healthcare System, Buffalo, NY, USA.
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11
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Fliesler SJ, Ramachandra Rao S, Nguyen MN, KhalafAllah MT, Pittler SJ. Vertebrate Animal Models of RP59: Current Status and Future Prospects. Int J Mol Sci 2022; 23:13324. [PMID: 36362109 PMCID: PMC9657489 DOI: 10.3390/ijms232113324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 10/27/2022] [Accepted: 10/28/2022] [Indexed: 09/20/2023] Open
Abstract
Retinitis pigmentosa-59 (RP59) is a rare, recessive form of RP, caused by mutations in the gene encoding DHDDS (dehydrodolichyl diphosphate synthase). DHDDS forms a heterotetrameric complex with Nogo-B receptor (NgBR; gene NUS1) to form a cis-prenyltransferase (CPT) enzyme complex, which is required for the synthesis of dolichol, which in turn is required for protein N-glycosylation as well as other glycosylation reactions in eukaryotic cells. Herein, we review the published phenotypic characteristics of RP59 models extant, with an emphasis on their ocular phenotypes, based primarily upon knock-in of known RP59-associated DHDDS mutations as well as cell type- and tissue-specific knockout of DHDDS alleles in mice. We also briefly review findings in RP59 patients with retinal disease and other patients with DHDDS mutations causing epilepsy and other neurologic disease. We discuss these findings in the context of addressing "knowledge gaps" in our current understanding of the underlying pathobiology mechanism of RP59, as well as their potential utility for developing therapeutic interventions to block the onset or to dampen the severity or progression of RP59.
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Affiliation(s)
- Steven J. Fliesler
- Departments of Ophthalmology and Biochemistry, Neuroscience Graduate Program, Jacobs School of Medicine, State University of New York—University at Buffalo, Buffalo, NY 14203, USA
- Research Service, VA Western NY Healthcare System, Buffalo, NY 14215, USA
| | - Sriganesh Ramachandra Rao
- Departments of Ophthalmology and Biochemistry, Neuroscience Graduate Program, Jacobs School of Medicine, State University of New York—University at Buffalo, Buffalo, NY 14203, USA
- Research Service, VA Western NY Healthcare System, Buffalo, NY 14215, USA
| | - Mai N. Nguyen
- Department of Optometry and Vision Science, Vision Science Research Center, School of Optometry, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Mahmoud Tawfik KhalafAllah
- Department of Optometry and Vision Science, Vision Science Research Center, School of Optometry, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Steven J. Pittler
- Department of Optometry and Vision Science, Vision Science Research Center, School of Optometry, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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12
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Patal R, Banin E, Batash T, Sharon D, Levy J. Ultra-widefield fundus autofluorescence imaging in patients with autosomal recessive retinitis pigmentosa reveals a genotype-phenotype correlation. Graefes Arch Clin Exp Ophthalmol 2022; 260:3471-3478. [PMID: 35501492 DOI: 10.1007/s00417-022-05683-w] [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: 01/19/2022] [Revised: 04/13/2022] [Accepted: 04/22/2022] [Indexed: 11/30/2022] Open
Abstract
PURPOSE To analyze the genotype-phenotype correlation in patients with retinitis pigmentosa (RP) caused by mutations in the FAM161A, DHDDS, or MAK genes using ultra-widefield fundus autofluorescence (UWF-FAF) imaging. METHODS Retrospective case series of patients with autosomal recessive RP (ARRP) with confirmed causative genetic mutations and available UWF-FAF imaging data. The UWF-FAF data were graded in a blinded fashion using the following criteria: the pattern of macular abnormalities on FAF, the presence or absence of horizontal linear hyperautofluorescence, the extent of decreased autofluorescence (DAF), the shape of DAF, and the presence of hyperautofluorescence at the optic disk. RESULTS A total of 43 patients (mean age of 47 ± 16 years, ranging from 17 to 79 years) with ARRP (86 eyes) were included in our analysis. Genotyping data revealed biallelic mutations in the FAM161A, DHDDS, and MAK genes in 20, 12, and 11 patients, respectively. We found significant differences between the three groups with respect to the pattern of macular abnormalities on FAF (p = 0.001), DAF configuration (p = 0.007), and extent of DAF (p = 0.037). The largest difference between groups was found for macular abnormalities on FAF, with DHDDS patients differing significantly from the MAK and FAM161A groups (p = 0.001). Specifically, DHDDS patients had a more abnormal macular FAF pattern and more widespread decrease in peripheral autofluorescence. No other parameters differed significantly between the three groups. CONCLUSIONS Patients with ARRP can present with specific UWF-FAF patterns based on the underlying causative gene. Future studies are warranted in order to expand this analysis to include additional genes, mutations, and patients as well as assessment of disease progression by following patients over longer periods of time.
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Affiliation(s)
- Rani Patal
- Department of Ophthalmology, Hadassah University Medical Center, Faculty of Medicine, Hebrew University, Jerusalem, Israel
| | - Eyal Banin
- Department of Ophthalmology, Hadassah University Medical Center, Faculty of Medicine, Hebrew University, Jerusalem, Israel
| | - Tomer Batash
- Department of Ophthalmology, Hadassah University Medical Center, Faculty of Medicine, Hebrew University, Jerusalem, Israel
| | - Dror Sharon
- Department of Ophthalmology, Hadassah University Medical Center, Faculty of Medicine, Hebrew University, Jerusalem, Israel
| | - Jaime Levy
- Department of Ophthalmology, Hadassah University Medical Center, Faculty of Medicine, Hebrew University, Jerusalem, Israel.
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13
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Sallum JMF, Kaur VP, Shaikh J, Banhazi J, Spera C, Aouadj C, Viriato D, Fischer MD. Epidemiology of Mutations in the 65-kDa Retinal Pigment Epithelium (RPE65) Gene-Mediated Inherited Retinal Dystrophies: A Systematic Literature Review. Adv Ther 2022; 39:1179-1198. [PMID: 35098484 PMCID: PMC8918161 DOI: 10.1007/s12325-021-02036-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 12/22/2021] [Indexed: 12/26/2022]
Abstract
INTRODUCTION Inherited retinal dystrophies (IRDs) represent a genetically diverse group of progressive, visually debilitating diseases. Adult and paediatric patients with vision loss due to IRD caused by biallelic mutations in the 65-kDa retinal pigment epithelium (RPE65) gene are often clinically diagnosed as retinitis pigmentosa (RP), and Leber congenital amaurosis (LCA). This study aimed to understand the epidemiological landscape of RPE65 gene-mediated IRD through a systematic review of the literature, as the current evidence base for its epidemiology is very limited. METHODS Medline, Embase, and other databases were searched for articles on the epidemiology of RPE65 gene-mediated IRDs from inception until June 2021. Studies were included if they were original research articles reporting the epidemiology of RP and LCA and/or proportion of RPE65 gene mutations in these clinically diagnosed or molecularly confirmed IRDs patients. RESULTS A total of 100 studies with relevant data were included in this systematic review. The range for prevalence of LCA and RP in the literature was 1.20-2.37 and 11.09-26.43 per 100,000, respectively. The proportion of RPE65 mutations in clinically diagnosed patients with LCA was found to be between ~ 2-16% within the US and major European countries (France, Germany, Italy, Spain, and the UK). This range was also comparable to our findings in the Asian region for RPE65-LCA (1.26-16.67%). Similarly, for these European countries, RPE65-RP was estimated between 0.23 and 1.94%, and RPE65-IRD range was 1.2-14%. Further, in the Americas region, mutations in RPE65 were reported to cause 1-3% of RP and 0.8-3.7% of IRD cases. Lastly, the RPE65-IRD range was 4.81-8% in the Middle East region. CONCLUSIONS There are significant variations in reporting of RPE65 proportions within countries as well as regions. Generating robust epidemiological evidence on RPE65 gene-mediated IRDs would be fundamental to support rare disease awareness, timely therapeutic intervention, and public health decision-making.
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Affiliation(s)
- Juliana M F Sallum
- Department of Ophthalmology, Universidade Federal de São Paulo, São Paulo, Brazil
- Instituto de Genética Ocular, São Paulo, Brazil
| | | | | | | | | | | | | | - M Dominik Fischer
- Centre for Ophthalmology, University Eye Hospital, University Hospital Tübingen, Tübingen, Germany
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
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14
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Jiao X, Xue Y, Yang S, Gong P, Niu Y, Wang Q, Yang H, Xiong H, Zhang Y, Yang Z. Phenotype of heterozygous variants of dehydrodolichol diphosphate synthase. Dev Med Child Neurol 2022; 64:125-134. [PMID: 34275143 DOI: 10.1111/dmcn.14976] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/02/2021] [Indexed: 11/28/2022]
Abstract
AIM To further identify and broaden the phenotypic characteristics and genotype spectrum of the dehydrodolichol diphosphate synthase (DHDDS) gene. METHOD Pathogenic variants of DHDDS were identified by whole-exome sequencing; clinical data of 10 patients (six males, four females; age range 2-14y; mean age 5y 9mo, SD 3y 3mo) were collected and analysed. RESULTS All patients had seizures, and myoclonic seizures could be seen in eight patients, with myoclonic status epilepticus in three. The interictal electroencephalogram (EEG) in four patients at seizure onset showed generalized slow waves, slow wave mixed spikes, and spike and waves. Tremor, ataxia, and hypertonia was observed in six, five, and three patients respectively. The results of short-latency somatosensory evoked potential in two patients were normal, and the symptom of tremor was captured on EEG without time-locked discharges in one patient, suggesting that the tremor in both patients was a motor impairment rather than myoclonic seizures. Global developmental delay occurred in all patients, among whom nine showed severe intellectual disability and one moderate. Five DHDDS variants were identified, three of which have not been reported previously. INTERPRETATION Myoclonic seizure is the most common seizure type in heterozygous DHDDS variants, while myoclonic status epilepticus can also occur. The pattern of interictal EEG discharges is characterized by slow waves rather than spike and waves, and generalized discharges was prominent.
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Affiliation(s)
- Xianru Jiao
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Yinan Xue
- Department of Pediatrics, Brain Hospital of Hunan Province, Changsha, China
| | - Sai Yang
- Department of Neurology, Hunan Children's Hospital, Changsha, China
| | - Pan Gong
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Yue Niu
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Qi Wang
- Department of Pediatrics, Brain Hospital of Hunan Province, Changsha, China
| | - Hui Yang
- Department of Pediatrics, Brain Hospital of Hunan Province, Changsha, China
| | - Hui Xiong
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Yuehua Zhang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Zhixian Yang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
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15
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Brandwine T, Ifrah R, Bialistoky T, Zaguri R, Rhodes-Mordov E, Mizrahi-Meissonnier L, Sharon D, Katanaev VL, Gerlitz O, Minke B. Knockdown of Dehydrodolichyl Diphosphate Synthase in the Drosophila Retina Leads to a Unique Pattern of Retinal Degeneration. Front Mol Neurosci 2021; 14:693967. [PMID: 34290587 PMCID: PMC8287061 DOI: 10.3389/fnmol.2021.693967] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 06/14/2021] [Indexed: 01/30/2023] Open
Abstract
Dehydrodolichyl diphosphate synthase (DHDDS) is a ubiquitously expressed enzyme that catalyzes cis-prenyl chain elongation to produce the poly-prenyl backbone of dolichol. It appears in all tissues including the nervous system and it is a highly conserved enzyme that can be found in all animal species. Individuals who have biallelic missense mutations in the DHDDS gene are presented with non-syndromic retinitis pigmentosa with unknown underlying mechanism. We have used the Drosophila model to compromise DHDDS ortholog gene (CG10778) in order to look for cellular and molecular mechanisms that, when defective, might be responsible for this retinal disease. The Gal4/UAS system was used to suppress the expression of CG10778 via RNAi-mediated-knockdown in various tissues. The resulting phenotypes were assessed using q-RT-PCR, transmission-electron-microscopy (TEM), electroretinogram, antibody staining and Western blot analysis. Targeted knockdown of CG10778-mRNA in the early embryo using the actin promoter or in the developing wings using the nub promoter resulted in lethality, or wings loss, respectively. Targeted expression of CG10778-RNAi using the glass multiple reporter (GMR)-Gal4 driver (GMR-DHDDS-RNAi) in the larva eye disc and pupal retina resulted in a complex phenotype: (a) TEM retinal sections revealed a unique pattern of retinal-degeneration, where photoreceptors R2 and R5 exhibited a nearly normal structure of their signaling-compartment (rhabdomere), but only at the region of the nucleus, while all other photoreceptors showed retinal degeneration at all regions. (b) Western blot analysis revealed a drastic reduction in rhodopsin levels in GMR-DHDDS-RNAi-flies and TEM sections showed an abnormal accumulation of endoplasmic reticulum (ER). To conclude, compromising DHDDS in the developing retina, while allowing formation of the retina, resulted in a unique pattern of retinal degeneration, characterized by a dramatic reduction in rhodopsin protein level and an abnormal accumulation of ER membranes in the photoreceptors cells, thus indicating that DHDDS is essential for normal retinal formation.
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Affiliation(s)
- Tal Brandwine
- Department of Medical Neurobiology, Faculty of Medicine and The Edmond and Lily Safra Center for Brain Sciences (ELSC), The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Reut Ifrah
- Department of Medical Neurobiology, Faculty of Medicine and The Edmond and Lily Safra Center for Brain Sciences (ELSC), The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Tzofia Bialistoky
- Department of Developmental Biology and Cancer Research, Faculty of Medicine, Institute for Medical Research Israel-Canada (IMRIC), The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Rachel Zaguri
- Department of Medical Neurobiology, Faculty of Medicine and The Edmond and Lily Safra Center for Brain Sciences (ELSC), The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Elisheva Rhodes-Mordov
- Department of Medical Neurobiology, Faculty of Medicine and The Edmond and Lily Safra Center for Brain Sciences (ELSC), The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Liliana Mizrahi-Meissonnier
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Dror Sharon
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Vladimir L Katanaev
- Department of Cell Physiology and Metabolism, Translational Research Centre in Oncohaematology, Faculty of Medicine, University of Geneva, Geneva, Switzerland.,School of Biomedicine, Far Eastern Federal University, Vladivostok, Russia
| | - Offer Gerlitz
- Department of Developmental Biology and Cancer Research, Faculty of Medicine, Institute for Medical Research Israel-Canada (IMRIC), The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Baruch Minke
- Department of Medical Neurobiology, Faculty of Medicine and The Edmond and Lily Safra Center for Brain Sciences (ELSC), The Hebrew University of Jerusalem, Jerusalem, Israel
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16
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In Silico identification of a common mobile element insertion in exon 4 of RP1. Sci Rep 2021; 11:13381. [PMID: 34183725 PMCID: PMC8238996 DOI: 10.1038/s41598-021-92834-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 06/14/2021] [Indexed: 11/18/2022] Open
Abstract
Mobile element insertions (MEIs) typically exceed the read lengths of short-read sequencing technologies and are therefore frequently missed. Recently, a founder Alu insertion in exon 4 of RP1 has been detected in Japanese patients with macular dystrophy by PCR and gel electrophoresis. We aimed to develop a grep search program for the detection of the Alu insertion in exon 4 of RP1 using unprocessed short reads. Among 494 unrelated Korean patients with inherited eye diseases, 273 patients with specific retinal phenotypes who were previously genotyped by targeted panel or whole exome sequencing were selected. Five probands had a single heterozygous truncating RP1 variant, and one of their unaffected parents also carry this variant. To find a hidden genetic variant, whole genome sequencing was performed in two patients, and it revealed AluY c.4052_4053ins328/p.(Tyr1352Alafs*9) insertion in RP1 exon 4. This AluY insertion was additionally identified in other 3 families, which was confirmed by PCR and gel electrophoresis. We developed simplified grep search program to detect this AluY insertion in RP1 exon 4. The simple grep search revealed a median variant allele frequency of 0.282 (interquartile range, 0.232–0.383), with no false-positive results using 120 control samples. The MEI in RP1 exon 4 was a common founder mutation in Korean, occurring in 1.8% of our cohort. The RP1-Alu grep program efficiently detected the AluY insertion, without the preprocessing of raw data or complex installation processes.
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17
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Murakami Y, Koyanagi Y, Fukushima M, Yoshimura M, Fujiwara K, Akiyama M, Momozawa Y, Ueno S, Terasaki H, Oishi A, Miyata M, Ikeda H, Tsujikawa A, Mizobuchi K, Hayashi T, Fujinami K, Tsunoda K, Park JY, Han J, Kim M, Lee CS, Kim SJ, Park TK, Joo K, Woo SJ, Ikeda Y, Sonoda KH. Genotype and Long-term Clinical Course of Bietti Crystalline Dystrophy in Korean and Japanese Patients. Ophthalmol Retina 2021; 5:1269-1279. [PMID: 33636399 DOI: 10.1016/j.oret.2021.02.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 02/16/2021] [Accepted: 02/16/2021] [Indexed: 11/28/2022]
Abstract
PURPOSE To investigate the genotype and long-term clinical phenotype of patients with Bietti crystalline dystrophy (BCD) in Korea and Japan. DESIGN Retrospective case series. PARTICIPANTS We analyzed 62 patients with clinical features of BCD who harbor pathogenic biallelic CYP4V2 variants in their homozygote or compound heterozygote. METHODS Data were collected from patient charts, including age, best-corrected visual acuity (BCVA), Goldmann perimetry results, fundus photography, OCT findings, fundus autofluorescence results, and electroretinography findings. We compared the clinical course of the patients with homozygous c.802-8_810de117insGC [exon7del], the most common mutation in the East Asian population, with those of the patients with other genotypes. MAIN OUTCOME MEASURES Best-corrected visual acuity, visual field (VF), and their changes during follow-up. RESULTS The mean age at the first visit was 55.2 years, with a mean follow-up of 7.1 years. The mean BCVAs at the first and last visits were 0.28 logarithm of the minimum angle of resolution (logMAR) and 0.89 logMAR, respectively. In genetic testing, c.802-8_810de117insGC was detected in 86 of 124 alleles of the patients, and 36 patients were homozygous for this mutation. The age, BCVA, VF area, central foveal thickness, and abnormal hypoautofluorescent area at either the first or last visit were not different between the exon7del homozygotes and the others. The mean BCVA changes per year were 0.089 logMAR in the exon7del homozygotes and 0.089 logMAR in the others. An age- and gender-adjusted linear regression analysis showed no association between the exon7del homozygote status and the rate of vision loss. Characteristic crystalline deposits in the posterior pole were generally observed in younger patients and disappeared over time along with progressive retinochoroidal atrophy. CONCLUSIONS Patients with BCD and a homozygote for c.802-8_810de117insGC accounted for more than 50% of this cohort of Korean and Japanese patients, and the clinical effect of this deleterious variant was not severe in the spectrum of CYP4V2 retinopathy.
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Affiliation(s)
- Yusuke Murakami
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
| | - Yoshito Koyanagi
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Masatoshi Fukushima
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Marika Yoshimura
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Kohta Fujiwara
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Masato Akiyama
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan; Department of Ocular Pathology and Imaging Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Yukihide Momozawa
- Laboratory for Genotyping Development, RIKEN Center for Integrative Medical Sciences, Kanagawa, Japan
| | - Shinji Ueno
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Hiroko Terasaki
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Akio Oishi
- Department of Ophthalmology and Visual Sciences, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Manabu Miyata
- Department of Ophthalmology and Visual Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Hanako Ikeda
- Department of Ophthalmology and Visual Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Akitaka Tsujikawa
- Department of Ophthalmology and Visual Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Kei Mizobuchi
- Department of Ophthalmology, The Jikei University School of Medicine, Tokyo, Japan
| | - Takaaki Hayashi
- Department of Ophthalmology, The Jikei University School of Medicine, Tokyo, Japan
| | - Kaoru Fujinami
- Division of Vision Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan
| | - Kazushige Tsunoda
- Division of Vision Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan
| | - Jun Young Park
- Department of Ophthalmology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
| | - Jinu Han
- Institute of Vision Research, Department of Ophthalmology, Gangnam Severance Hospital, Yonsei University, Seoul, Korea
| | - Min Kim
- Institute of Vision Research, Department of Ophthalmology, Gangnam Severance Hospital, Yonsei University, Seoul, Korea
| | - Christopher Seungkyu Lee
- Institute of Vision Research, Department of Ophthalmology, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Sang Jin Kim
- Department of Ophthalmology, Samsung Medical Center, Seoul, Korea
| | - Tae Kwann Park
- Department of Ophthalmology, Soonchunhyang University Hospital, Bucheon, Korea
| | - Kwangsic Joo
- Department of Ophthalmology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
| | - Se Joon Woo
- Department of Ophthalmology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
| | - Yasuhiro Ikeda
- Department of Ophthalmology, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan
| | - Koh-Hei Sonoda
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
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18
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Beryozkin A, Khateb S, Idrobo-Robalino CA, Khan MI, Cremers FPM, Obolensky A, Hanany M, Mezer E, Chowers I, Newman H, Ben-Yosef T, Sharon D, Banin E. Unique combination of clinical features in a large cohort of 100 patients with retinitis pigmentosa caused by FAM161A mutations. Sci Rep 2020; 10:15156. [PMID: 32938956 PMCID: PMC7495424 DOI: 10.1038/s41598-020-72028-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 07/30/2020] [Indexed: 01/06/2023] Open
Abstract
FAM161A mutations are the most common cause of autosomal recessive retinitis pigmentosa in the Israeli-Jewish population. We aimed to characterize the spectrum of FAM161A-associated phenotypes and identify characteristic clinical features. We identified 114 bi-allelic FAM161A patients and obtained clinical records of 100 of these patients. The most frequent initial symptom was night blindness. Best-corrected visual acuity was largely preserved through the first three decades of life and severely deteriorated during the 4th–5th decades. Most patients manifest moderate-high myopia. Visual fields were markedly constricted from early ages, but maintained for decades. Bone spicule-like pigmentary changes appeared relatively late, accompanied by nummular pigmentation. Full-field electroretinography responses were usually non-detectable at first testing. Fundus autofluorescence showed a hyper-autofluorescent ring around the fovea in all patients already at young ages. Macular ocular coherence tomography showed relative preservation of the outer nuclear layer and ellipsoid zone in the fovea, and frank cystoid macular changes were very rare. Interestingly, patients with a homozygous nonsense mutation manifest somewhat more severe disease. Our clinical analysis is one of the largest ever reported for RP caused by a single gene allowing identification of characteristic clinical features and may be relevant for future application of novel therapies.
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Affiliation(s)
- Avigail Beryozkin
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University Jerusalem, Jerusalem, Israel
| | - Samer Khateb
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University Jerusalem, Jerusalem, Israel
| | - Carlos Alberto Idrobo-Robalino
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University Jerusalem, Jerusalem, Israel
| | - Muhammad Imran Khan
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Frans P M Cremers
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
| | - Alexey Obolensky
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University Jerusalem, Jerusalem, Israel
| | - Mor Hanany
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University Jerusalem, Jerusalem, Israel
| | - Eedy Mezer
- Department of Ophthalmology, Rambam Health Care Campus, Haifa, Israel.,Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
| | - Itay Chowers
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University Jerusalem, Jerusalem, Israel
| | - Hadas Newman
- Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv, Israel.,Department of Ophthalmology, Tel-Aviv Sourasky Medical Center, Tel Aviv, Israel
| | - Tamar Ben-Yosef
- Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
| | - Dror Sharon
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University Jerusalem, Jerusalem, Israel.
| | - Eyal Banin
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University Jerusalem, Jerusalem, Israel.
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19
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Edani BH, Grabińska KA, Zhang R, Park EJ, Siciliano B, Surmacz L, Ha Y, Sessa WC. Structural elucidation of the cis-prenyltransferase NgBR/DHDDS complex reveals insights in regulation of protein glycosylation. Proc Natl Acad Sci U S A 2020; 117:20794-20802. [PMID: 32817466 PMCID: PMC7456142 DOI: 10.1073/pnas.2008381117] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Cis-prenyltransferase (cis-PTase) catalyzes the rate-limiting step in the synthesis of glycosyl carrier lipids required for protein glycosylation in the lumen of endoplasmic reticulum. Here, we report the crystal structure of the human NgBR/DHDDS complex, which represents an atomic resolution structure for any heterodimeric cis-PTase. The crystal structure sheds light on how NgBR stabilizes DHDDS through dimerization, participates in the enzyme's active site through its C-terminal -RXG- motif, and how phospholipids markedly stimulate cis-PTase activity. Comparison of NgBR/DHDDS with homodimeric cis-PTase structures leads to a model where the elongating isoprene chain extends beyond the enzyme's active site tunnel, and an insert within the α3 helix helps to stabilize this energetically unfavorable state to enable long-chain synthesis to occur. These data provide unique insights into how heterodimeric cis-PTases have evolved from their ancestral, homodimeric forms to fulfill their function in long-chain polyprenol synthesis.
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Affiliation(s)
- Ban H Edani
- Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, CT 06520
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520
| | - Kariona A Grabińska
- Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, CT 06520
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520
| | - Rong Zhang
- Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, CT 06520
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520
| | - Eon Joo Park
- Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, CT 06520
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520
| | - Benjamin Siciliano
- Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, CT 06520
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520
| | - Liliana Surmacz
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106, Warsaw, Poland
| | - Ya Ha
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520;
| | - William C Sessa
- Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, CT 06520;
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520
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20
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Ramachandra Rao S, Skelton LA, Wu F, Onysk A, Spolnik G, Danikiewicz W, Butler MC, Stacks DA, Surmacz L, Mu X, Swiezewska E, Pittler SJ, Fliesler SJ. Retinal Degeneration Caused by Rod-Specific Dhdds Ablation Occurs without Concomitant Inhibition of Protein N-Glycosylation. iScience 2020; 23:101198. [PMID: 32526701 PMCID: PMC7287266 DOI: 10.1016/j.isci.2020.101198] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 04/10/2020] [Accepted: 05/20/2020] [Indexed: 12/16/2022] Open
Abstract
Dehydrodolichyl diphosphate synthase (DHDDS) catalyzes the committed step in dolichol synthesis. Recessive mutations in DHDDS cause retinitis pigmentosa (RP59), resulting in blindness. We hypothesized that rod photoreceptor-specific ablation of Dhdds would cause retinal degeneration due to diminished dolichol-dependent protein N-glycosylation. Dhddsflx/flx mice were crossed with rod-specific Cre recombinase-expressing (Rho-iCre75) mice to generate rod-specific Dhdds knockout mice (Dhddsflx/flx iCre+). In vivo morphological and electrophysiological evaluation of Dhddsflx/flx iCre+ retinas revealed mild retinal dysfunction at postnatal (PN) 4 weeks, compared with age-matched controls; however, rapid photoreceptor degeneration ensued, resulting in almost complete loss of rods and cones by PN 6 weeks. Retina dolichol levels were markedly decreased by PN 4 weeks in Dhddsflx/flx iCre+ mice, relative to controls; despite this, N-glycosylation of retinal proteins, including opsin (the dominant rod-specific glycoprotein), persisted in Dhddsflx/flx iCre+ mice. These findings challenge the conventional mechanistic view of RP59 as a congenital disorder of glycosylation. Deletion of Dhdds in rod cells caused rapid retinal degeneration in mice Retinal dolichol levels markedly decreased before onset of degeneration Protein N-glycosylation was uncompromised despite Dhdds deletion Degeneration also involved gliosis, microglial activation, and phagoptosis
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Affiliation(s)
- Sriganesh Ramachandra Rao
- Department of Ophthalmology/Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, State University of New York- University at Buffalo, Buffalo, NY 14209, USA; Research Service, VA Western NY Healthcare System, Buffalo, NY 142015, USA; Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, State University of New York- University at Buffalo, Buffalo, NY 14203, USA
| | - Lara A Skelton
- Department of Ophthalmology/Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, State University of New York- University at Buffalo, Buffalo, NY 14209, USA; Research Service, VA Western NY Healthcare System, Buffalo, NY 142015, USA; Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, State University of New York- University at Buffalo, Buffalo, NY 14203, USA
| | - Fuguo Wu
- Department of Ophthalmology/Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, State University of New York- University at Buffalo, Buffalo, NY 14209, USA; Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, State University of New York- University at Buffalo, Buffalo, NY 14203, USA; New York State Center of Excellence in Bioinformatics and Life Sciences, State University of New York- University at Buffalo, Buffalo, NY 14203, USA
| | - Agnieszka Onysk
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Grzegorz Spolnik
- Institute of Organic Chemistry, Polish Academy of Sciences, Warsaw 02106, Poland
| | - Witold Danikiewicz
- Institute of Organic Chemistry, Polish Academy of Sciences, Warsaw 02106, Poland
| | - Mark C Butler
- Department of Ophthalmology/Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, State University of New York- University at Buffalo, Buffalo, NY 14209, USA; Research Service, VA Western NY Healthcare System, Buffalo, NY 142015, USA
| | - Delores A Stacks
- Department of Optometry and Vision Science, Vision Science Research Center, School of Optometry, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Liliana Surmacz
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Xiuqian Mu
- Department of Ophthalmology/Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, State University of New York- University at Buffalo, Buffalo, NY 14209, USA; Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, State University of New York- University at Buffalo, Buffalo, NY 14203, USA; New York State Center of Excellence in Bioinformatics and Life Sciences, State University of New York- University at Buffalo, Buffalo, NY 14203, USA
| | - Ewa Swiezewska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Steven J Pittler
- Department of Optometry and Vision Science, Vision Science Research Center, School of Optometry, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Steven J Fliesler
- Department of Ophthalmology/Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, State University of New York- University at Buffalo, Buffalo, NY 14209, USA; Research Service, VA Western NY Healthcare System, Buffalo, NY 142015, USA; Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, State University of New York- University at Buffalo, Buffalo, NY 14203, USA.
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21
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DeRamus ML, Davis SJ, Rao SR, Nyankerh C, Stacks D, Kraft TW, Fliesler SJ, Pittler SJ. Selective Ablation of Dehydrodolichyl Diphosphate Synthase in Murine Retinal Pigment Epithelium (RPE) Causes RPE Atrophy and Retinal Degeneration. Cells 2020; 9:E771. [PMID: 32245241 PMCID: PMC7140717 DOI: 10.3390/cells9030771] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 03/06/2020] [Accepted: 03/17/2020] [Indexed: 02/07/2023] Open
Abstract
Patients with certain defects in the dehydrodolichyl diphosphate synthase (DHDDS) gene (RP59; OMIM #613861) exhibit classic symptoms of retinitis pigmentosa, as well as macular changes, suggestive of retinal pigment epithelium (RPE) involvement. The DHDDS enzyme is ubiquitously required for several pathways of protein glycosylation. We wish to understand the basis for selective ocular pathology associated with certain DHDDS mutations and the contribution of specific ocular cell types to the pathology of mutant Dhdds-mediated retinal degeneration. To circumvent embryonic lethality associated with Dhdds knockout, we generated a Cre-dependent knockout allele of murine Dhdds (Dhddsflx/flx). We used targeted Cre expression to study the importance of the enzyme in the RPE. Structural alterations of the RPE and retina including reduction in outer retinal thickness, cell layer disruption, and increased RPE hyper-reflectivity were apparent at one postnatal month. At three months, RPE and photoreceptor disruption was observed non-uniformly across the retina as well as RPE transmigration into the photoreceptor layer, external limiting membrane descent towards the RPE, and patchy loss of photoreceptors. Functional loss measured by electroretinography was consistent with structural loss showing scotopic a- and b-wave reductions of 83% and 77%, respectively, at three months. These results indicate that RPE dysfunction contributes to DHDDS mutation-mediated pathology and suggests a more complicated disease mechanism than simply disruption of glycosylation.
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Affiliation(s)
- Marci L. DeRamus
- Department of Optometry and Vision Science, Vision Science Research Center, University of Alabama at Birmingham, Birmingham, AL 35294, USA; (M.L.D.); (S.J.D.); (C.N.); (D.S.); (T.W.K.)
| | - Stephanie J. Davis
- Department of Optometry and Vision Science, Vision Science Research Center, University of Alabama at Birmingham, Birmingham, AL 35294, USA; (M.L.D.); (S.J.D.); (C.N.); (D.S.); (T.W.K.)
| | - Sriganesh Ramachandra Rao
- Departments of Ophthalmology and Biochemistry, State University of New York-University at Buffalo, Buffalo, NY 14209, USA; and Research Service, VA Western NY Healthcare System, Buffalo, NY 14215, USA; (S.R.R.); (S.J.F.)
| | - Cyril Nyankerh
- Department of Optometry and Vision Science, Vision Science Research Center, University of Alabama at Birmingham, Birmingham, AL 35294, USA; (M.L.D.); (S.J.D.); (C.N.); (D.S.); (T.W.K.)
| | - Delores Stacks
- Department of Optometry and Vision Science, Vision Science Research Center, University of Alabama at Birmingham, Birmingham, AL 35294, USA; (M.L.D.); (S.J.D.); (C.N.); (D.S.); (T.W.K.)
| | - Timothy W. Kraft
- Department of Optometry and Vision Science, Vision Science Research Center, University of Alabama at Birmingham, Birmingham, AL 35294, USA; (M.L.D.); (S.J.D.); (C.N.); (D.S.); (T.W.K.)
| | - Steven J. Fliesler
- Departments of Ophthalmology and Biochemistry, State University of New York-University at Buffalo, Buffalo, NY 14209, USA; and Research Service, VA Western NY Healthcare System, Buffalo, NY 14215, USA; (S.R.R.); (S.J.F.)
| | - Steven J. Pittler
- Department of Optometry and Vision Science, Vision Science Research Center, University of Alabama at Birmingham, Birmingham, AL 35294, USA; (M.L.D.); (S.J.D.); (C.N.); (D.S.); (T.W.K.)
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22
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Yang D, Yao Q, Li Y, Xu Y, Wang J, Zhao H, Liu F, Zhang Z, Liu Y, Bie X, Wang Y, Xu L, Luan Y, Yang S, Yang G, He Y. A c.544_618del75bp mutation in the splicing factor gene PRPF31 is involved in non-syndromic retinitis pigmentosa by reducing the level of mRNA expression. Ophthalmic Physiol Opt 2020; 40:289-299. [PMID: 32031697 DOI: 10.1111/opo.12672] [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] [Received: 09/28/2019] [Accepted: 01/02/2020] [Indexed: 01/08/2023]
Abstract
PURPOSE A previous study reported a novel c.544_618del75bp mutation in exon 7 of the PRPF31 gene in a Chinese family with autosomal dominant retinal pigmentosa (ADRP). However, the selected pedigree was a small part of the whole family and the function of the c.544_618del75bp mutation was not explored deeply. The aim of the present study was to validate the previous results and explore the functional significance of the c.544_618del75bp mutation. METHODS We extended the size of the ADRP pedigree and sequenced DNA and cDNA of the PRPF31 gene for all members of the family and 100 healthy controls. Real-time quantitative polymerase chain reaction (PCR) analysis was performed on the cDNA of patients in the family and cell culture, plasmids transfection and western blot analysis were done to evaluate the functional effect of the mutation in vitro. RESULTS Sanger sequencing showed that the mutation was present in all patients and absent in all normal individuals, except for participant III-9. Bioinformatics analysis revealed that the c.544_618del75bp mutation caused a 25 amino acid deletion in the PRPF31 protein. In addition, the mRNA expression assay revealed that the mRNA expression level of the PRPF31 and RP9 genes were significantly lower in RP patients than controls (p < 0.05). Finally, the in vitro transfection assay demonstrated that the mRNA expression level of the mutant transfection group was significantly lower than the wild-type transfection group (p < 0.05). CONCLUSIONS Our study suggested that the c.544_618del75bp mutation in the PRPF31 gene was a causative mutation in this ADRP family and affected the expression of RP9 gene by influencing the formation of U4/U6-U5 tri-snRNP, eventually leading to the occurrence of RP.
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Affiliation(s)
- Dongzhi Yang
- School of Life Sciences, Zhengzhou University, Zhengzhou, China
| | - Qihui Yao
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Ya Li
- Henan Eye Institute, Henan Provincial People's Hospital, Zhengzhou, China
| | - Yan Xu
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Jun Wang
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Huiling Zhao
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Fuyong Liu
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Zhaojing Zhang
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Yang Liu
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Xiaoshuai Bie
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Yuanli Wang
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Liyan Xu
- Henan Eye Institute, Henan Provincial People's Hospital, Zhengzhou, China
| | - Yingying Luan
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Shangdong Yang
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Ge Yang
- Department of Ophthalmology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Ying He
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
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23
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Gao FJ, Hu FY, Xu P, Qi YH, Li JK, Zhang YJ, Chen F, Chang Q, Song F, Shen SM, Xu GZ, Wu JH. Expanding the clinical and genetic spectrum of Heimler syndrome. Orphanet J Rare Dis 2019; 14:290. [PMID: 31831025 PMCID: PMC6909578 DOI: 10.1186/s13023-019-1243-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 10/29/2019] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Heimler syndrome (HS) is a rare hereditary systemic disorder, partial clinically overlapping with Usher syndrome. So far, our knowledge of HS is very limited, many cases are misdiagnosed or may not even be diagnosed at all. This study aimed to analyze the clinical and genetic characteristics of HS, and to evaluate potential phenotype-genotype correlations. RESULTS Two HS cases caused by PEX1 mutations were identified, and a novel likely pathogenic mutation, PEX1 c.895_896insTATA, was found. The main ophthalmic finding of the two patients was consistent with retinitis pigmentosa accompanied by cystoid macular edema, but short axial length and hyperopia were also observed as two previously unreported ocular phenotypes. Analysis of the literature showed that of the 29 HS patients previously reported, 12 had PEX6 mutations, 10 had PEX1 mutations, two had PEX26 mutations, and the remaining patients were not genetically tested. Three novel genotype-phenotype correlations were revealed from analysis of these patients. First, most genotypes of every HS patient include at least one missense variant; second, at least one mutation in PEX1 or PEX6 gene affects the AAA-ATPase region in every HS patient with retinal dystrophy, suggesting AAA-ATPase region is a hypermutable region in patients with a retinal dystrophy; third, there are no significant differences between PEX1-, PEX6-, and PEX26-associated phenotypes. CONCLUSION Next-generation sequencing is important for the diagnosis of HS. This study expands the clinical and genetic spectrum of HS, and provides additional insights into genotype-phenotype correlations, which is vital for accurate clinical practice, genetic counseling, and pathogenesis studies.
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Affiliation(s)
- Feng-Juan Gao
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China.,Key Laboratory of Myopia (Fudan University), Chinese Academy of Medical Sciences, National Health Commission, Shanghai, China
| | - Fang-Yuan Hu
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China.,Key Laboratory of Myopia (Fudan University), Chinese Academy of Medical Sciences, National Health Commission, Shanghai, China
| | - Ping Xu
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China.,Key Laboratory of Myopia (Fudan University), Chinese Academy of Medical Sciences, National Health Commission, Shanghai, China
| | - Yu-He Qi
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China.,Key Laboratory of Myopia (Fudan University), Chinese Academy of Medical Sciences, National Health Commission, Shanghai, China
| | - Jian-Kang Li
- BGI-Shenzhen, Shenzhen, China.,Department of Computer Science, City University of Hong Kong, 83 Tat Chee Ave, Kowloon, Hong Kong
| | - Yong-Jin Zhang
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China.,Key Laboratory of Myopia (Fudan University), Chinese Academy of Medical Sciences, National Health Commission, Shanghai, China
| | - Fang Chen
- BGI-Shenzhen, Shenzhen, China.,Laboratory of Genomics and Molecular Biomedicine, Department of Biology, University of Copenhagen, Copenhagen, Denmark.,Shenzhen Engineering Laboratory for Birth Defects Screening, BGI-Shenzhen, Shenzhen, China
| | - Qing Chang
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China.,Key Laboratory of Myopia (Fudan University), Chinese Academy of Medical Sciences, National Health Commission, Shanghai, China
| | - Fang Song
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China
| | | | - Ge-Zhi Xu
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China. .,Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China. .,Key Laboratory of Myopia (Fudan University), Chinese Academy of Medical Sciences, National Health Commission, Shanghai, China.
| | - Ji-Hong Wu
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China. .,Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China. .,Key Laboratory of Myopia (Fudan University), Chinese Academy of Medical Sciences, National Health Commission, Shanghai, China.
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24
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Kimchi A, Meiner V, Silverstein S, Macarov M, Mor-Shaked H, Blumenfeld A, Audo I, Zeitz C, Mechoulam H, Banin E, Sharon D, Yahalom C. An Ashkenazi Jewish founder mutation in CACNA1F causes retinal phenotype in both hemizygous males and heterozygous female carriers. Ophthalmic Genet 2019; 40:443-448. [PMID: 31651202 DOI: 10.1080/13816810.2019.1681008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Background: Mutations in CACNA1F have been mainly associated with X-linked incomplete congenital stationary night blindness (icCSNB). Variable phenotypic expression in females was reported in some families. We report here three non-related Ashkenazi Jewish families originating in Eastern Europe, that included males and a many affected females, initially diagnosed with variable retinal phenotypes.Materials and Methods: Whole exome sequencing (WES), Sanger sequencing and microsatellite haplotyping were used for genetic analysis. Complete ophthalmologic examination was performed including visual acuity, refraction, colour vision, slit-lamp, fundoscopy and electroretinography (ERG).Results: We identified four affected males, showing moderate visual impairment, and seven female carriers, six of them presenting mild to moderate visual impairment. Infantile nystagmus was found in all affected males and in 5/7 females. Nyctalopia and myopia were common in both males and females. Initial clinical differential diagnosis included cone-dystrophy, cone-rod dystrophy, cone-dystrophy with supernormal rod response or CSNB based on ERG results. WES and Sanger sequencing revealed a previously described missense mutation c.2225T>G; p.(F742C) in CACNA1F (NM_001256789.2) in all three families, encompassed by a shared haplotypeConclusions: Our data suggests that p.(F742C) in CACNA1F is an X-linked founder mutation in Ashkenazi Jews originating in Eastern Europe. This mutation causes a mild-to-moderate icCSNB phenotype, expressed in most female carriers. A targeted test for this variant in suspected patients may initiate diagnostic analysis. Our results highlight the relevance of WES in the clinic, allowing fast and accurate diagnosis for unclear and variable clinical phenotype and in pedigrees with multiple possible inheritance patterns.
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Affiliation(s)
- Adva Kimchi
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel.,Department of Genetics and Metabolic Diseases, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Vardiella Meiner
- Department of Genetics and Metabolic Diseases, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Shira Silverstein
- Department of Genetics and Metabolic Diseases, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Michal Macarov
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel.,Department of Genetics and Metabolic Diseases, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Hagar Mor-Shaked
- Department of Genetics and Metabolic Diseases, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Anat Blumenfeld
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Isabelle Audo
- Institut de la vision, Sorbonne Université, INSERM, Paris, France.,CHNO des Quinze-Vingts, DHU Sight Restore, INSERM-DHOS, Paris, France.,Institute of Ophthalmology, University College of London, London, UK
| | - Christina Zeitz
- Institut de la vision, Sorbonne Université, INSERM, Paris, France
| | - Hadas Mechoulam
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Eyal Banin
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Dror Sharon
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Claudia Yahalom
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
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25
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Genetic and Clinical Findings in a Large Cohort of Chinese Patients with Suspected Retinitis Pigmentosa. Ophthalmology 2019; 126:1549-1556. [PMID: 31054281 DOI: 10.1016/j.ophtha.2019.04.038] [Citation(s) in RCA: 76] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2019] [Revised: 04/18/2019] [Accepted: 04/23/2019] [Indexed: 12/21/2022] Open
Abstract
PURPOSE To characterize the genetic landscape of patients with suspected retinitis pigmentosa (RP) in the Chinese population. DESIGN Cohort study. PARTICIPANTS A total of 1243 patients of Chinese origin with clinically suspected RP and their available family members (n = 2701) were recruited. METHODS All patients and available family members were screened using multigene panel testing (including 586 eye disease-associated genes), followed by clinical variant interpretation. MAIN OUTCOME MEASURES Diagnostic yield, the 17 most commonly implicated genes, age at onset, de novo mutations, and clinical usefulness of genetic testing. RESULTS Overall, 72.08% of patients received a molecular diagnosis, and the 17 top genes covered 75.63% of diagnostic cases. Diagnostic yield was higher among patients in the early-onset subgroup (≤5 years old, 79.58%) than in the childhood or adolescence-onset subgroup (6-16 years old, 73.74%) and late-onset subgroup (≥17 years old, 65.99%). Moreover, different genes associated with different onset ages and subgroups with different onset ages showed a diverse mutation spectrum. Only 11 de novo mutations (3.18%) were identified. Furthermore, 16.84% of the patients who received a molecular diagnosis had refinement of the initial clinical diagnoses, and the remaining 83.16% received definite genetic subtypes of RP. CONCLUSIONS This large cohort study provides population-based data of the genome landscape of patients with suspected RP in China. The diagnostic yield was significantly higher than that in previous studies, and the mutation spectrum is completely different with other populations. Genetic testing improves the chance to establish a precise diagnosis, identifies features not previously determined, and allows a more accurate refinement of risk to family members. Our results not only expand the existing genotypic spectrum but also serve as an efficient reference for the design of panel-based genetic diagnostic testing and genetic counseling for patients with suspected RP in China.
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Gray JM, Orlans HO, Shanks M, Clouston P, MacLaren RE. Slowly progressive retinitis pigmentosa caused by two novel mutations in the MAK gene. Ophthalmic Genet 2018; 39:508-511. [PMID: 29781741 DOI: 10.1080/13816810.2018.1474369] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
BACKGROUND The growing number of clinical trials currently underway for inherited retinal diseases has highlighted the importance of achieving a molecular diagnosis for all new cases presenting to hospital eye services. The male germ cell-associated kinase (MAK) gene encodes a cilium-associated protein selectively expressed in the retina and testis, and has recently been implicated in autosomal recessive retinitis pigmentosa (RP). Whole exome sequencing has previously identified a homozygous Alu insertion in probands with recessive RP and nonsense and missense mutations have also been reported. MATERIALS AND METHODS Here we describe two novel mutations in different alleles of the MAK gene in a 75-year-old British female, who had a clinical diagnosis of RP () with onset in the fourth decade and no relevant family history. The mutations were established through next generation sequencing of a panel of 111 genes associated with RP and RP-like phenotypes. RESULTS Two novel null mutations were identified within the MAK gene. The first c.1195_1196delAC p.(Thr399fs), was a two base-pair deletion creating a frame-shift in exon 9 predicted to result in nonsense-mediated decay. The second, c.279-2A>G, involved the splice acceptor consensus site upstream of exon 4, predicted to lead to aberrant splicing. CONCLUSIONS The natural history of this individual's RP is consistent with previously described MAK mutations, being significantly milder than that associated with other photoreceptor ciliopathies. We suggest inclusion of MAK as part of wider genetic testing in all individuals presenting with RP.
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Affiliation(s)
- Joanna Monika Gray
- a Nuffield Laboratory of Ophthalmology & Oxford Biomedical Research Centre , University of Oxford , Oxford , UK.,b Oxford Eye Hospital , John Radcliffe Hospital , Oxford , UK
| | - Harry Otway Orlans
- a Nuffield Laboratory of Ophthalmology & Oxford Biomedical Research Centre , University of Oxford , Oxford , UK.,b Oxford Eye Hospital , John Radcliffe Hospital , Oxford , UK
| | - Morag Shanks
- c Oxford Medical Genetics Laboratories , Oxford University Hospitals NHS Foundation Trust , Oxford , UK
| | - Penny Clouston
- c Oxford Medical Genetics Laboratories , Oxford University Hospitals NHS Foundation Trust , Oxford , UK
| | - Robert Elvis MacLaren
- a Nuffield Laboratory of Ophthalmology & Oxford Biomedical Research Centre , University of Oxford , Oxford , UK.,b Oxford Eye Hospital , John Radcliffe Hospital , Oxford , UK
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