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Natural Disease Course in Usher Syndrome Patients Harboring USH2A Variant p.Cys870* in Exon 13, Amenable to Exon Skipping Therapy. Genes (Basel) 2023; 14:genes14030652. [PMID: 36980924 PMCID: PMC10048357 DOI: 10.3390/genes14030652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 02/08/2023] [Accepted: 02/13/2023] [Indexed: 03/08/2023] Open
Abstract
The aim of the study was to determine the rate of retinal degeneration in patients with c.2610C>A (p.Cys870*) in USH2A exon 13, amenable to exon skipping therapy. There were nine patients from seven families, three of whom were male (two were homozygous). Seven patients had follow-up data (median of 11 years). Analysis included best corrected visual acuity (BCVA, decimal Snellen), visual field (Goldmann perimetry target II/4), fundus autofluorescence (FAF), optical coherence tomography (OCT), and microperimetry (MP). The median age at the onset of nyctalopia was 20 years (range, 8–35 years of age). At the first exam, at a median age of 42 years, the median BCVA was 0.5 (0.2–1.0), and the median visual field diameter was 23° (5°–114°). Imaging showed a hyperautofluorescent ring delineating preserved foveal photoreceptors in 78% (7/9) of patients, while 22% (2/9) had a hyperautofluorescent patch or atrophy, reflecting advanced disease. Survival analysis predicted that 50% of patients reach legal blindness based on a visual field diameter < 20° at the age of 52 (95% CI, 45–59) and legal blindness based on a BCVA ≤ 0. 1 (20/200) at the age of 55 (95% CI, 46–66). Visual field constriction occurred at the median rate of radial 1.5 deg/year, and hyperautofluorescent ring constriction occurred at the median rate of 34 μm/year. A non-null second allele was found in two patients: p.Thr4315Pro and p.Arg303His; the patient with p.Arg303His had a milder disease. The rates of progression will be useful in the design and execution of clinical trials.
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Characteristics of Retinitis Pigmentosa Associated with ADGRV1 and Comparison with USH2A in Patients from a Multicentric Usher Syndrome Study Treatrush. Int J Mol Sci 2021; 22:ijms221910352. [PMID: 34638692 PMCID: PMC8509029 DOI: 10.3390/ijms221910352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 09/18/2021] [Accepted: 09/20/2021] [Indexed: 11/17/2022] Open
Abstract
In contrast to USH2A, variants in ADGRV1 are a minor cause of Usher syndrome type 2, and the associated phenotype is less known. The purpose of the study was to characterize the retinal phenotype of 18 ADGRV1 patients (9 male, 9 female; median age 52 years) and compare it with that of 204 USH2A patients (111 male, 93 female; median age 43 years) in terms of nyctalopia onset, best corrected visual acuity (BCVA), fundus autofluorescence (FAF), and optical coherence tomography (OCT) features. There was no statistical difference in the median age at onset (30 and 18 years; Mann–Whitney U test, p = 0.13); the mean age when 50% of the patients reached legal blindness (≥1.0 log MAR) based on visual acuity (64 years for both groups; log-rank, p = 0.3); the risk of developing advanced retinal degeneration (patch or atrophy) with age (multiple logistic regression, p = 0.8); or the frequency of cystoid macular edema (31% vs. 26%, Fisher’s exact test, p = 0.4). ADGRV1 and USH2A retinopathy were indistinguishable in all major functional and structural characteristics, suggesting that the loss of function of the corresponding proteins produces similar effects in the retina. The results are important for counseling ADGRV1 patients, who represent the minor patient subgroup.
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de Joya EM, Colbert BM, Tang PC, Lam BL, Yang J, Blanton SH, Dykxhoorn DM, Liu X. Usher Syndrome in the Inner Ear: Etiologies and Advances in Gene Therapy. Int J Mol Sci 2021; 22:3910. [PMID: 33920085 PMCID: PMC8068832 DOI: 10.3390/ijms22083910] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 04/02/2021] [Accepted: 04/05/2021] [Indexed: 02/06/2023] Open
Abstract
Hearing loss is the most common sensory disorder with ~466 million people worldwide affected, representing about 5% of the population. A substantial portion of hearing loss is genetic. Hearing loss can either be non-syndromic, if hearing loss is the only clinical manifestation, or syndromic, if the hearing loss is accompanied by a collage of other clinical manifestations. Usher syndrome is a syndromic form of genetic hearing loss that is accompanied by impaired vision associated with retinitis pigmentosa and, in many cases, vestibular dysfunction. It is the most common cause of deaf-blindness. Currently cochlear implantation or hearing aids are the only treatments for Usher-related hearing loss. However, gene therapy has shown promise in treating Usher-related retinitis pigmentosa. Here we review how the etiologies of Usher-related hearing loss make it a good candidate for gene therapy and discuss how various forms of gene therapy could be applied to Usher-related hearing loss.
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Affiliation(s)
- Evan M. de Joya
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; (E.M.J.); (B.M.C.); (P.-C.T.); (S.H.B.)
- Dr. John T. Macdonald Foundation Department of Human Genetics, John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL 33136, USA;
| | - Brett M. Colbert
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; (E.M.J.); (B.M.C.); (P.-C.T.); (S.H.B.)
- Dr. John T. Macdonald Foundation Department of Human Genetics, John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL 33136, USA;
- Medical Scientist Training Program, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Pei-Ciao Tang
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; (E.M.J.); (B.M.C.); (P.-C.T.); (S.H.B.)
| | - Byron L. Lam
- Bascom Palmer Eye Institute, University of Miami School of Medicine, Miami, FL 33136, USA;
| | - Jun Yang
- John A. Moran Eye Center, Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, UT 84132, USA;
| | - Susan H. Blanton
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; (E.M.J.); (B.M.C.); (P.-C.T.); (S.H.B.)
- Dr. John T. Macdonald Foundation Department of Human Genetics, John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL 33136, USA;
| | - Derek M. Dykxhoorn
- Dr. John T. Macdonald Foundation Department of Human Genetics, John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL 33136, USA;
| | - Xuezhong Liu
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; (E.M.J.); (B.M.C.); (P.-C.T.); (S.H.B.)
- Dr. John T. Macdonald Foundation Department of Human Genetics, John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL 33136, USA;
- Interdisciplinary Stem Cell Institute, University of Miami Miller School of Medicine, Miami, FL 33136, USA
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Ambrosio L, Hansen RM, Moskowitz A, Oza A, Barrett D, Manganella J, Medina G, Kawai K, Fulton AB, Kenna M. Dark-adapted threshold and electroretinogram for diagnosis of Usher syndrome. Doc Ophthalmol 2021; 143:39-51. [PMID: 33511521 DOI: 10.1007/s10633-021-09818-y] [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: 09/12/2020] [Accepted: 01/07/2021] [Indexed: 12/21/2022]
Abstract
PURPOSE To determine the utility of ophthalmology evaluation, dark-adapted threshold, and full-field electroretinogram for early detection of Usher syndrome in young patients with bilateral sensorineural hearing loss. METHODS We identified 39 patients with secure genetic diagnoses of Usher Syndrome. Visual acuity, spherical equivalent, fundus appearance, dark-adapted threshold, and full-field electroretinogram results were summarized and compared to those in a group of healthy controls with normal hearing. In those Usher patients with repeated measures, regression analysis was done to evaluate for change in visual acuity and dark-adapted threshold with age. Spherical equivalent and full-field electroretinogram responses from dark- and light-adapted eyes were evaluated as a function of age. RESULTS The majority of initial visual acuity and spherical equivalent results were within normal limits for age. Visual acuity and dark-adapted threshold worsened significantly with age in Usher type 1 but not in Usher type 2. At initial test, full-field electroretinogram responses from dark- and light-adapted eyes were abnormal in 53% of patients. Remarkably, nearly half of our patients (17% of Usher type 1 and 30% of Usher type 2) would have been missed by tests of retinal function alone if evaluated before age 10. CONCLUSIONS Although there is an association of abnormal dark-adapted threshold and full-field electroretinogram at young ages in Usher patients, it appears that a small but important proportion of patients would not be detected by tests of retinal function alone. Thus, genetic testing is needed to secure a diagnosis of Usher syndrome.
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Affiliation(s)
- Lucia Ambrosio
- Department of Ophthalmology, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA. .,Department of Ophthalmology, Harvard Medical School, 25 Shattuck Street, Boston, MA, 02115, USA.
| | - Ronald M Hansen
- Department of Ophthalmology, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA.,Department of Ophthalmology, Harvard Medical School, 25 Shattuck Street, Boston, MA, 02115, USA
| | - Anne Moskowitz
- Department of Ophthalmology, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA.,Department of Ophthalmology, Harvard Medical School, 25 Shattuck Street, Boston, MA, 02115, USA
| | - Andrea Oza
- Laboratory for Molecular Medicine, Partners HealthCare Personalized Medicine, 65 Landsdowne Street, Cambridge, MA, 02139, USA
| | - Devon Barrett
- Department of Otolaryngology and Communication Enhancement, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA
| | - Juliana Manganella
- Department of Otolaryngology and Communication Enhancement, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA
| | - Genevieve Medina
- Department of Otolaryngology and Communication Enhancement, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA
| | - Kosuke Kawai
- Department of Otolaryngology and Communication Enhancement, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA.,Department of Otolaryngology, Harvard Medical School, 25 Shattuck Street, Boston, MA, 02115, USA
| | - Anne B Fulton
- Department of Ophthalmology, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA.,Department of Ophthalmology, Harvard Medical School, 25 Shattuck Street, Boston, MA, 02115, USA
| | - Margaret Kenna
- Department of Otolaryngology and Communication Enhancement, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA.,Department of Otolaryngology, Harvard Medical School, 25 Shattuck Street, Boston, MA, 02115, USA
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5
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Xing D, Zhou H, Yu R, Wang L, Hu L, Li Z, Li X. Targeted exome sequencing identified a novel USH2A mutation in a Chinese usher syndrome family: a case report. BMC Ophthalmol 2020; 20:485. [PMID: 33302902 PMCID: PMC7727220 DOI: 10.1186/s12886-020-01711-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 10/29/2020] [Indexed: 12/14/2022] Open
Abstract
Background Usher syndrome is a disease with a heterogeneous phenotype and genotype. Our purpose was to identify the gene mutation in a Chinese family with Usher syndrome type 2 and describe the clinical features. Case presentation A 23-year-old man complained of a 10-year duration of nyctalopia and a 3-year decline in visual acuity of both eyes accompanied by congenital dysaudia. To clarify the diagnosis, the clinical symptoms were observed and analysed in combination with comprehensive ophthalmologic examinations as well as genetic analysis (targeted exome sequencing, TES). A typical clinical presentation of Usher syndrome of the fundus was found, including a waxy yellow-like disc, bone-spicule formations and retinal vessel stenosis. Optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) showed loss of the ellipsoid zone and a reduction in paracaval vessel density in both eyes. Genetic analysis identified a novel homozygous c.8483_8486del (p.Ser2828*) mutation in USH2A. The mutation resulted in premature termination of translation and caused the deletion of 19 fibronectin type 3 domains (FN3), transmembrane (TM) region and PDZ-binding motif domain, which play an important role in protein binding. After combining the clinical manifestations and genetic results, the patient was diagnosed with Usher syndrome type 2. Conclusion We found a novel c.8483_8486del mutation in the USH2A gene through TES techniques. The results broaden the spectrum of mutations in Usher syndrome type 2 and suggest that a combination of clinical information and molecular diagnosis via TES could help Usher syndrome patients obtain a better diagnosis. Supplementary Information The online version contains supplementary material available at 10.1186/s12886-020-01711-7.
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Affiliation(s)
- Dongjun Xing
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin International Joint Research and Development Centre of Ophthalmology and Vision Science, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, 251 Fukang Road, Tianjin, 300384, China
| | - Huaiyu Zhou
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin International Joint Research and Development Centre of Ophthalmology and Vision Science, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, 251 Fukang Road, Tianjin, 300384, China
| | - Rongguo Yu
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin International Joint Research and Development Centre of Ophthalmology and Vision Science, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, 251 Fukang Road, Tianjin, 300384, China
| | - Linni Wang
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin International Joint Research and Development Centre of Ophthalmology and Vision Science, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, 251 Fukang Road, Tianjin, 300384, China
| | - Liying Hu
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin International Joint Research and Development Centre of Ophthalmology and Vision Science, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, 251 Fukang Road, Tianjin, 300384, China
| | - Zhiqing Li
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin International Joint Research and Development Centre of Ophthalmology and Vision Science, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, 251 Fukang Road, Tianjin, 300384, China.
| | - Xiaorong Li
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin International Joint Research and Development Centre of Ophthalmology and Vision Science, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, 251 Fukang Road, Tianjin, 300384, China.
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Toms M, Pagarkar W, Moosajee M. Usher syndrome: clinical features, molecular genetics and advancing therapeutics. Ther Adv Ophthalmol 2020; 12:2515841420952194. [PMID: 32995707 PMCID: PMC7502997 DOI: 10.1177/2515841420952194] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 07/27/2020] [Indexed: 01/12/2023] Open
Abstract
Usher syndrome has three subtypes, each being clinically and genetically heterogeneous characterised by sensorineural hearing loss and retinitis pigmentosa (RP), with or without vestibular dysfunction. It is the most common cause of deaf–blindness worldwide with a prevalence of between 4 and 17 in 100 000. To date, 10 causative genes have been identified for Usher syndrome, with MYO7A accounting for >50% of type 1 and USH2A contributing to approximately 80% of type 2 Usher syndrome. Variants in these genes can also cause non-syndromic RP and deafness. Genotype–phenotype correlations have been described for several of the Usher genes. Hearing loss is managed with hearing aids and cochlear implants, which has made a significant improvement in quality of life for patients. While there is currently no available approved treatment for the RP, various therapeutic strategies are in development or in clinical trials for Usher syndrome, including gene replacement, gene editing, antisense oligonucleotides and small molecule drugs.
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Affiliation(s)
- Maria Toms
- UCL Institute of Ophthalmology, London, UK; The Francis Crick Institute, London, UK
| | - Waheeda Pagarkar
- Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK; University College London Hospitals NHS Foundation Trust, London, UK
| | - Mariya Moosajee
- Development, Ageing and Disease, UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
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7
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Wang K, Statler B, Ramos M, DeBenedictis MJ, Babiuch A, Yuan A, Traboulsi EI. Hickam's Dictum: Pseudoxanthoma elasticum and Usher syndrome in a single patient. Ophthalmic Genet 2020; 41:465-469. [PMID: 32664777 DOI: 10.1080/13816810.2020.1790616] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
BACKGROUND To report the case of a patient with two distinct genetic systemic diseases - pseudoxanthoma elasticum (PXE) and Usher syndrome - confirmed by genetic testing. MATERIALS AND METHODS Single Retrospective Case Report. RESULTS A 36-year-old woman presented with acute central vision loss of the left eye (OS). Fundus exam revealed choroidal neovascularization OS in the setting of angioid streaks secondary to an underlying diagnosis of PXE. Unexpectedly, she also exhibited peripheral bony spicules with significant visual field constriction. Physical exam revealed skin papules on her neck and hearing loss. The presence of angioid streaks and skin findings was compatible with PXE; the etiology of her pigmentary retinopathy and hearing loss was elucidated using genetic testing. The patient was found to be compound heterozygous for pathogenic variants in both the ABCC6 and USH2A genes, confirming the diagnosis of two rare disorders in a single patient. CONCLUSIONS PXE and Usher syndrome are rare systemic disorders that cause distinctive retinal abnormalities. This report highlights the importance of genetic testing in diagnosing uncommon hereditary retinal disorders and outlines the progression of disease over 6 years.
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Affiliation(s)
- Kevin Wang
- Cleveland Clinic, Cole Eye Institute , Cleveland, Ohio, USA
| | | | - Michael Ramos
- Cleveland Clinic, Cole Eye Institute , Cleveland, Ohio, USA
| | | | - Amy Babiuch
- Cleveland Clinic, Cole Eye Institute , Cleveland, Ohio, USA
| | - Alex Yuan
- Cleveland Clinic, Cole Eye Institute , Cleveland, Ohio, USA
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Wang H, Wan Y, Yang Y, Li H, Mao L, Gao S, Xu J, Wang J. Novel compound heterozygous mutations in OCA2 gene associated with non-syndromic oculocutaneous albinism in a Chinese Han patient: a case report. BMC MEDICAL GENETICS 2019; 20:130. [PMID: 31345173 PMCID: PMC6659248 DOI: 10.1186/s12881-019-0850-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 06/19/2019] [Indexed: 11/24/2022]
Abstract
Background Oculocutaneous albinism (OCA) is a group of rare genetically heterogeneous disorders. The present study aimed to identify the genetic cause of a Chinese Han family with non-syndromic oculocutaneous albinism (OCA). Case presentation Here, we report an 11-month-old male proband from a Chinese Han non-consanguineous family, who presented with milky skin, yellow white hair, nystagmus, astigmatism, and hypermetropia. We performed the targeted next-generation sequencing (NGS) on the proband and identified two novel compound heterozygous variants (c.1865 T > C (p.Leu622Pro) and exons 17–21 deletion) in OCA2 gene associated with OCA type 2 (OCA2, OMIM 203200). Meanwhile, a previously reported heterozygous mutation (c.4805G > A) in MYO7 gene related with Usher syndrome type 1B was found. The online tools SIFT, PolyPhen-2, and Mutation Taster predicted variant c.1865 T > C was probably damaging. The residue p.Leu622 was in a highly conserved region among species by CLUSTALW. Three-dimensional homology model with I-TASSER indicated that p.Leu622Pro variant disturbed the formation of the α-helix, resulting in a random coil structure. The gross deletion (exons 17–21) in OCA2 gene has was not been reported previously. These two novel variants in OCA2 gene were inherited from each parent respectively, after verification by Sanger sequencing and quantitative PCR (qPCR) in the family. Conclusions This study indicates the two novel compound heterozygous mutations in OCA2 gene may be responsible for clinical manifestations of OCA2. It expands the mutation spectrum of OCA2 gene and is helpful to screen for large deletions with targeted NGS protocol in monogenic disease. It also assists the genetic counselling, carrier screening and personalized healthcare of the disease. Electronic supplementary material The online version of this article (10.1186/s12881-019-0850-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Hairong Wang
- Anhui Clinical Laboratories, BGI-Anhui, BGI-Shenzhen, Weisan Road, Fuyang, 236000, China
| | - Yang Wan
- Department of Obstetrics and Gynecology, Fuyang People's Hospital, Fuyang, 236000, China
| | - Yun Yang
- Anhui Clinical Laboratories, BGI-Anhui, BGI-Shenzhen, Weisan Road, Fuyang, 236000, China.,Department of Obstetrics and Gynecology, The Second Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China
| | - Hao Li
- Anhui Clinical Laboratories, BGI-Anhui, BGI-Shenzhen, Weisan Road, Fuyang, 236000, China
| | - Liangwei Mao
- Anhui Clinical Laboratories, BGI-Anhui, BGI-Shenzhen, Weisan Road, Fuyang, 236000, China.,College of Life Sciences, Hubei University, Wuhan, 430062, China
| | - Shuyang Gao
- BGI Genomics, BGI-Shenzhen, Shenzhen, 518083, China
| | - Jingjing Xu
- Prenatal diagnosis center, Department of Obstetrics and Gynecology, The First Affiliated Hospital of University of Science and Technology of China, Hefei, 230071, China
| | - Jing Wang
- Prenatal diagnosis center, Department of Obstetrics and Gynecology, The First Affiliated Hospital of University of Science and Technology of China, Hefei, 230071, China.
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Li X, Huang S, Yuan Y, Lu Y, Zhang D, Wang X, Yuan H, Han W, Dai P. Detecting novel mutations and combined Klinefelter syndrome in Usher syndrome cases. Acta Otolaryngol 2019; 139:479-486. [PMID: 31035849 DOI: 10.1080/00016489.2019.1603397] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
BACKGROUND Usher syndrome (USH) is an autosomal recessive disease characterized by hearing loss, vision loss, and occasionally vestibular dysfunction. Klinefelter syndrome (KS) is an X chromosome polyploidy characterized by one or more additional X chromosomes in males. To date, there has been no report of USH combined with KS. OBJECTIVES This study examined the causative genes in three Chinese probands with congenital hearing loss. MATERIAL AND METHODS Targeted next-generation sequencing (NGS) was performed to identify mutations in three probands with hearing loss. Low-coverage whole-genome sequencing (WGS) analysis of aneuploidy was used to verify the chromosome aneuploidy. RESULTS Four novel MYO7A mutations were identified in two USH1 probands who were initially diagnosed with nonsyndromic hearing loss until the onset of vision loss. Another case was initially diagnosed with nonsyndromic hearing loss and USH2 and KS were discovered incidentally after the genetic analysis. CONCLUSIONS Our findings expand the mutation spectrum of MYO7A. This is also the first report of concomitant USH and KS. Genetic testing can help with clinical management, particularly if an unrecognized syndromic disorder is identified before the onset of additional symptoms. A clinical genetic evaluation is recommended as part of the diagnostic work-up in congenital hearing loss.
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Affiliation(s)
- Xiaohong Li
- Department of Otolaryngology, Head and Neck Surgery, Chinese PLA General Hospital, Beijing, PR China
| | - Shasha Huang
- Department of Otolaryngology, Head and Neck Surgery, Chinese PLA General Hospital, Beijing, PR China
| | - Yongyi Yuan
- Department of Otolaryngology, Head and Neck Surgery, Chinese PLA General Hospital, Beijing, PR China
| | - Yu Lu
- Medical Genetics Center, The First Hospital Affiliated to Army Medical University, Chongqing, PR China
| | - Dejun Zhang
- Department of Otolaryngology, Head and Neck Surgery, Chinese PLA General Hospital, Beijing, PR China
- Department of Otolaryngology, Head and Neck Surgery, The Second Hospital of Jilin University, Changchun, PR China
| | | | - Huijun Yuan
- Medical Genetics Center, The First Hospital Affiliated to Army Medical University, Chongqing, PR China
| | - Weiju Han
- Department of Otolaryngology, Head and Neck Surgery, Chinese PLA General Hospital, Beijing, PR China
| | - Pu Dai
- Department of Otolaryngology, Head and Neck Surgery, Chinese PLA General Hospital, Beijing, PR China
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Arcous M, Putois O, Dalle-Nazébi S, Kerbourch S, Cariou A, Ben Aissa I, Marlin S, Potier R. Psychosocial determinants associated with quality of life in people with usher syndrome. A scoping review. Disabil Rehabil 2019; 42:2809-2820. [PMID: 30974979 DOI: 10.1080/09638288.2019.1571637] [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: 01/14/2023]
Abstract
Background: In Usher syndrome, deafness is congenital and blindness is acquired. Therefore, the progressive loss of one of the two senses forces individuals with this syndrome to reorganize their everyday tasks and relationships, creating new strategies to communicate, access information, and move within a given space. This reorganization can interfere with the subjects' capacity to build a good quality of life.Methods: We conducted a scoping review of both peer-reviewed and gray literature, to identify existing evidence of the role of psychosocial determinants on the quality of life of people with Usher syndrome.Results: Twenty-one references met the inclusion criteria. Findings suggest that people with Usher syndrome seem to adjust their life habits to their condition, maintaining hope for the future, and believe in their capacities to accomplish their goals in spite of the various difficulties they encounter. However, this scoping review highlights a lack of research on adaptive strategies, as well as a lack of knowledge concerning the integration of the syndrome in one's identity, the relations to caregivers, and the specificities of the psychotherapeutic support. More information on these topics would enable better-adjusted social, psychotherapeutic, and medical responses.Implications for rehabilitationUsher syndrome, a rare genetic disease, leads to deafblindness, a cluster of related multiple sensory disabilities. People with Usher encounter several obstacles in their daily life. It is also difficult to adapt to the progressive loss of hearing and sight.This paper proposes a scoping review: we identify the main adaptation strategies used by people with Usher Syndrome in order to become autonomous in spite of these obstacles. In becoming more autonomous, they come to a better quality of life.We summarize the most frequent adaptation strategies (at school, work, leisure, interpersonal relationships, etc.) to help programs aimed at rehabilitation for people with Usher syndrome, and to find unexplored research perspectives (e.g., psychotherapies).
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Affiliation(s)
- Marine Arcous
- Denis Diderot - Sorbonne Paris Cité, Université VII, Paris, France
| | - Olivier Putois
- Faculty of Psychology, Université de Strasbourg, Strasbourg, France.,Department of Psychiatry, Mental Health and Addictology, Strasbourg University Hospital, Strasbourg, France
| | | | | | | | - Ines Ben Aissa
- Assistance Publique-Hôpitaux de Paris, Hôpital Necker-Enfants Malades, Paris, France.,Hôpitaux universitaires de Strasbourg-Filière de santé maladie rare, SENSGENE, Strasbourg, France
| | - Sandrine Marlin
- Assistance Publique-Hôpitaux de Paris, Hôpital Necker-Enfants Malades, Paris, France.,Hôpitaux universitaires de Strasbourg-Filière de santé maladie rare, SENSGENE, Strasbourg, France.,Sorbonne Paris Cité, Université Paris Descartes, Paris, France
| | - Rémy Potier
- Denis Diderot - Sorbonne Paris Cité, Université VII, Paris, France
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Fuster-García C, García-García G, Jaijo T, Fornés N, Ayuso C, Fernández-Burriel M, Sánchez-De la Morena A, Aller E, Millán JM. High-throughput sequencing for the molecular diagnosis of Usher syndrome reveals 42 novel mutations and consolidates CEP250 as Usher-like disease causative. Sci Rep 2018; 8:17113. [PMID: 30459346 PMCID: PMC6244211 DOI: 10.1038/s41598-018-35085-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 10/17/2018] [Indexed: 01/09/2023] Open
Abstract
Usher syndrome is a rare disorder causing retinitis pigmentosa, together with sensorineural hearing loss. Due to the phenotypic and genetic heterogeneity of this disease, the best method to screen the causative mutations is by high-throughput sequencing. In this study, we tested a semiconductor chip based sequencing approach with 77 unrelated patients, as a molecular diagnosis routine. In addition, Multiplex Ligation-dependent Probe Amplification and microarray-based Comparative Genomic Hybridization techniques were applied to detect large rearrangements, and minigene assays were performed to confirm the mRNA processing aberrations caused by splice-site mutations. The designed panel included all the USH causative genes (MYO7A, USH1C, CDH23, PCDH15, USH1G, CIB2, USH2A, ADGRV1, WHRN and CLRN1) as well as four uncertainly associated genes (HARS, PDZD7, CEP250 and C2orf71). The outcome showed an overall mutation detection ratio of 82.8% and allowed the identification of 42 novel putatively pathogenic mutations. Furthermore, we detected two novel nonsense mutations in CEP250 in a patient with a disease mimicking Usher syndrome that associates visual impairment due to cone-rod dystrophy and progressive hearing loss. Therefore, this approach proved reliable results for the molecular diagnosis of the disease and also allowed the consolidation of the CEP250 gene as disease causative for an Usher-like phenotype.
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Affiliation(s)
- Carla Fuster-García
- Grupo de Investigación en Biomedicina Molecular, Celular y Genómica, Instituto de Investigación Sanitaria La Fe (IIS La Fe), Valencia, Spain
| | - Gema García-García
- Grupo de Investigación en Biomedicina Molecular, Celular y Genómica, Instituto de Investigación Sanitaria La Fe (IIS La Fe), Valencia, Spain.
- CIBER de Enfermedades Raras (CIBERER), Madrid, Spain.
| | - Teresa Jaijo
- Grupo de Investigación en Biomedicina Molecular, Celular y Genómica, Instituto de Investigación Sanitaria La Fe (IIS La Fe), Valencia, Spain
- CIBER de Enfermedades Raras (CIBERER), Madrid, Spain
- Unidad de Genética y Diagnóstico Prenatal, Hospital Universitario y Politécnico La Fe, Valencia, Spain
| | - Neus Fornés
- Grupo de Investigación en Biomedicina Molecular, Celular y Genómica, Instituto de Investigación Sanitaria La Fe (IIS La Fe), Valencia, Spain
| | - Carmen Ayuso
- CIBER de Enfermedades Raras (CIBERER), Madrid, Spain
- Servicio de Genética, Fundación Jiménez Díaz, University Hospital, Instituto de Investigación Sanitaria Fundación Jiménez Díaz IIS-FJD, UAM, Madrid, Spain
| | | | | | - Elena Aller
- Grupo de Investigación en Biomedicina Molecular, Celular y Genómica, Instituto de Investigación Sanitaria La Fe (IIS La Fe), Valencia, Spain
- CIBER de Enfermedades Raras (CIBERER), Madrid, Spain
- Unidad de Genética y Diagnóstico Prenatal, Hospital Universitario y Politécnico La Fe, Valencia, Spain
| | - José M Millán
- Grupo de Investigación en Biomedicina Molecular, Celular y Genómica, Instituto de Investigación Sanitaria La Fe (IIS La Fe), Valencia, Spain
- CIBER de Enfermedades Raras (CIBERER), Madrid, Spain
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Cochlear Implantation in Patients With Usher Syndrome Type IIa Increases Performance and Quality of Life. Otol Neurotol 2018; 38:e120-e127. [PMID: 28498263 DOI: 10.1097/mao.0000000000001441] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES Usher syndrome type IIa (USH2a) is characterized by congenital moderate to severe hearing impairment and retinitis pigmentosa. Hearing rehabilitation starts in early childhood with the application of hearing aids. In some patients with USH2a, severe progression of hearing impairment leads to insufficient speech intelligibility with hearing aids and issues with adequate communication and safety. Cochlear implantation (CI) is the next step in rehabilitation of such patients. This study evaluates the performance and benefit of CI in patients with USH2a. DESIGN Retrospective case-control study to evaluate the performance and benefit of CI in 16 postlingually deaf adults (eight patients with USH2a and eight matched controls). Performance and benefit were evaluated by a speech intelligibility test and three quality-of-life questionnaires. RESULTS Patients with USH2a with a mean age of 59 years at implantation exhibited good performance after CI. The phoneme scores improved significantly from 41 to 87% in patients with USH2a (p = 0.02) and from 30 to 86% in the control group (p = 0.001). The results of the questionnaire survey demonstrated a clear benefit from CI. There were no differences in performance or benefit between patients with USH2a and control patients before and after CI. CONCLUSIONS CI increases speech intelligibility and improves quality of life in patients with USH2a.
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Abstract
OBJECTIVE PDZD7 was identified in 2009 in a family with apparent nonsyndromic sensorineural hearing loss. However, subsequent clinical reports have associated PDZD7 with digenic Usher syndrome, the most common cause of deaf-blindness, or as a modifier of retinal disease. No further reports have validated this gene for nonsyndromic hearing loss, intuitively calling correct genotype-phenotype association into question. This report describes a validating second case for biallelic mutations in PDZD7 causing nonsyndromic mild to severe sensorineural hearing loss. It also provides detailed audiometric and ophthalmologic data excluding Usher syndrome in both the present proband (proband 1) and the first proband described in 2009 (proband 2). DESIGN Proband 1 was sequenced using a custom-designed next generation sequencing panel consisting of 151 deafness genes. Bioinformatics analysis and filtering disclosed two PDZD7 sequence variants (c.1648C>T, p.Q550* and c.2107del, p.S703Vfs*20). Segregation testing followed in the family. For both probands, audiograms were collected and analyzed for progressive hearing loss and detailed ophthalmic evaluations were performed including electroretinography. RESULTS Proband 1 demonstrated a prelingual, nonsyndromic, sensorineural hearing loss that progressed in the higher frequencies between 4 and 9 years old. PDZD7 segregation analysis confirmed biallelic inheritance (compound heterozygosity). Mutation analysis determined the c.1648C>T mutation as novel and reported the c.2107del deletion as rs397516633 with a calculated minor allele frequency of 0.000018. Clinical evaluation spanning well over a decade in proband 2 disclosed bilateral, nonprogressive hearing loss. Both probands showed healthy retinas, excluding Usher syndrome-like changes in the eye. CONCLUSIONS PDZD7 is confirmed as a bona fide autosomal recessive nonsyndromic hearing loss gene. In both probands, there was no evidence of impaired vision or ophthalmic pathology. As the current understanding of PDZD7 mutations bridge Mendelian and complex phenotypes, the authors recommend careful variant interpretation, since PDZD7 is one of many genes associated with both Usher syndrome and autosomal recessive nonsyndromic hearing loss. Additional reports are required for understanding the complete phenotypic spectrum of this gene, including the possibility of high-frequency progression, as well as noise-induced hearing loss susceptibility in adult carriers. This report rules out all forms of Usher syndrome with an onset before 12 and 15 years old in probands 1 and 2, respectively. However, due to the young ages of the probands, this report is uninformative regarding older patients.
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Xiong A, Haithcock J, Liu Y, Eusner L, McConnell M, White HD, Belknap B, Forgacs E. The shaker-1 mouse myosin VIIa deafness mutation results in a severely reduced rate of the ATP hydrolysis step. J Biol Chem 2017; 293:819-829. [PMID: 29167268 DOI: 10.1074/jbc.m117.810119] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 11/21/2017] [Indexed: 11/06/2022] Open
Abstract
Mutations in the MYO7A gene, encoding the motor protein myosin VIIa, can cause Usher 1B, a deafness/blindness syndrome in humans, and the shaker-1 phenotype, characterized by deafness, head tossing, and circling behavior, in mice. Myosin VIIa is responsible for tension bearing and the transduction mechanism in the stereocilia and for melanosome transport in the retina, in line with the phenotypic outcomes observed in mice. However, the effect of the shaker-1 mutation, a R502P amino acid substitution, on the motor function is unclear. To explore this question, we determined the kinetic properties and the effect on the filopodial tip localization of the recombinant mouse myosin VIIa-5IQ-SAH R502P (myoVIIa-sh1) construct. Interestingly, although residue 502 is localized to a region thought to be involved in interacting with actin, the kinetic parameters for actin binding changed only slightly for the mutant construct. However, the rate constant for ATP hydrolysis (k+H + k-H) was reduced by ∼200-fold from 12 s-1 to 0.05 s-1, making the hydrolysis step the rate-limiting step of the ATPase cycle in the presence and absence of actin. Given that wild-type mouse myosin VIIa is a slow, high-duty ratio, monomeric motor, this altered hydrolysis rate would reduce activity to extremely low levels. Indeed, the translocation to the filopodial tips was hampered by the diminished motor function of a dimeric construct of the shaker-1 mutant. We conclude that the diminished motor activity of this mutant is most likely responsible for impaired hearing in the shaker-1 mice.
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Affiliation(s)
- Ailian Xiong
- From the Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk, Virginia 23507
| | - Jessica Haithcock
- From the Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk, Virginia 23507
| | - Yingying Liu
- From the Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk, Virginia 23507
| | - Lauren Eusner
- From the Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk, Virginia 23507
| | - Matthew McConnell
- From the Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk, Virginia 23507
| | - Howard D White
- From the Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk, Virginia 23507
| | - Betty Belknap
- From the Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk, Virginia 23507
| | - Eva Forgacs
- From the Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk, Virginia 23507
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Magliulo G, Iannella G, Gagliardi S, Iozzo N, Plateroti R, Mariottini A, Torricelli F. Usher's Syndrome Type II: A Comparative Study of Genetic Mutations and Vestibular System Evaluation. Otolaryngol Head Neck Surg 2017; 157:853-860. [PMID: 28653555 DOI: 10.1177/0194599817715235] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Objective Usher's syndrome type II (USH2) is characterized by moderate to profound congenital hearing loss, later onset of retinitis pigmentosa, and normal vestibular function. Recently, a study investigating the vestibular function of USH2 patients demonstrated a pathologic response to vestibular tests. In this cross-sectional study we performed vestibular tests of a group patients with genetic diagnosis of USH2 syndrome to demonstrate if vestibular damage is present in USH2 patients. Study Design Cross-sectional study. Setting Tertiary referral center. Subjects and Methods Mutated genes of 7 patients with a clinical diagnosis of USH2 were evaluated. Vestibular function was investigated by audiometry, Fitzgerald-Hallpike caloric vestibular testing, cervical vestibular evoked myogenic potentials (C-VEMPs), ocular vestibular evoked myogenic potentials (O-VEMPs), and video head impulse test (v-HIT). Results Genetic tests confirmed the USH2 diagnosis in 5 of 7 patients examined, with 1 patient reporting a unique mutation on genetic tests. Four (80%) of the 5 patients with a genetic diagnosis of USH2 showed pathological O-VEMPs. Two patients (40%) reported bilateral absent or abnormal values of C-VEMPs. The superior semicircular canal presented a significant deficit in 2 (40%) patients. The same 2 cases showed a pathologic response of the v-HIT of the horizontal semicircular canal. Finally, the posterior semicircular canal presented a significant deficit in 4 (40.0%) patients. Conclusion A vestibular evaluation with vestibular evoked myogenic potentials and v-HIT seems to identify latent damage to the vestibular receptors of USH2 patients.
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Affiliation(s)
| | | | - Silvia Gagliardi
- 1 Organi di Senso Department, University "la Sapienza," Rome, Italy
| | - Nicola Iozzo
- 1 Organi di Senso Department, University "la Sapienza," Rome, Italy
| | - Rocco Plateroti
- 1 Organi di Senso Department, University "la Sapienza," Rome, Italy
| | - Alessandro Mariottini
- 2 Department of Genetic Diagnosis, Azienda Ospedaliero-Universitaria Careggi, Florence, Italy
| | - Francesca Torricelli
- 2 Department of Genetic Diagnosis, Azienda Ospedaliero-Universitaria Careggi, Florence, Italy
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Biswas P, Duncan JL, Maranhao B, Kozak I, Branham K, Gabriel L, Lin JH, Barteselli G, Navani M, Suk J, Parke M, Schlechter C, Weleber RG, Heckenlively JR, Dagnelie G, Lee P, Riazuddin SA, Ayyagari R. Genetic analysis of 10 pedigrees with inherited retinal degeneration by exome sequencing and phenotype-genotype association. Physiol Genomics 2017; 49:216-229. [PMID: 28130426 PMCID: PMC5407181 DOI: 10.1152/physiolgenomics.00096.2016] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Revised: 01/23/2017] [Accepted: 01/24/2017] [Indexed: 12/31/2022] Open
Abstract
Our purpose was to identify causative mutations and characterize the phenotype associated with the genotype in 10 unrelated families with autosomal recessive retinal degeneration. Ophthalmic evaluation and DNA isolation were carried out in 10 pedigrees with inherited retinal degenerations (IRD). Exomes of probands from eight pedigrees were captured using Nimblegen V2/V3 or Agilent V5+UTR kits, and sequencing was performed on Illumina HiSeq. The DHDDS gene was screened for mutations in the remaining two pedigrees with Ashkenazi Jewish ancestry. Exome variants were filtered to detect candidate causal variants using exomeSuite software. Segregation and ethnicity-matched control sample analysis were performed by dideoxy sequencing. Retinal histology of a patient with DHDDS mutation was studied by microscopy. Genetic analysis identified six known mutations in ABCA4 (p.Gly1961Glu, p.Ala1773Val, c.5461-10T>C), RPE65 (p.Tyr249Cys, p.Gly484Asp), PDE6B (p.Lys706Ter) and DHDDS (p.Lys42Glu) and ten novel potentially pathogenic variants in CERKL (p.Met323Val fsX20), RPE65 (p.Phe252Ser, Thr454Leu fsX31), ARL6 (p.Arg121His), USH2A (p.Gly3142Ter, p.Cys3294Trp), PDE6B (p.Gln652Ter), and DHDDS (p.Thr206Ala) genes. Among these, variants/mutations in two separate genes were observed to segregate with IRD in two pedigrees. Retinal histopathology of a patient with a DHDDS mutation showed severe degeneration of retinal layers with relative preservation of the retinal pigment epithelium. Analysis of exome variants in ten pedigrees revealed nine novel potential disease-causing variants and nine previously reported homozygous or compound heterozygous mutations in the CERKL, ABCA4, RPE65, ARL6, USH2A, PDE6B, and DHDDS genes. Mutations that could be sufficient to cause pathology were observed in more than one gene in one pedigree.
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Affiliation(s)
- Pooja Biswas
- Shiley Eye Institute, University of California San Diego, La Jolla, California
| | - Jacque L Duncan
- Ophthalmology, University of California San Francisco, San Francisco, California
| | - Bruno Maranhao
- Shiley Eye Institute, University of California San Diego, La Jolla, California
| | - Igor Kozak
- King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia
| | - Kari Branham
- Ophthalmology & Visual Science, University of Michigan Kellogg Eye Center, Ann Arbor, Michigan
| | - Luis Gabriel
- Genetics and Ophthalmology, Genelabor, Goiânia, Brazil
| | - Jonathan H Lin
- Shiley Eye Institute, University of California San Diego, La Jolla, California
| | - Giulio Barteselli
- Shiley Eye Institute, University of California San Diego, La Jolla, California
| | - Mili Navani
- Shiley Eye Institute, University of California San Diego, La Jolla, California
| | - John Suk
- Shiley Eye Institute, University of California San Diego, La Jolla, California
| | - Michelle Parke
- Shiley Eye Institute, University of California San Diego, La Jolla, California
| | | | - Richard G Weleber
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon; and
| | - John R Heckenlively
- Ophthalmology & Visual Science, University of Michigan Kellogg Eye Center, Ann Arbor, Michigan
| | - Gislin Dagnelie
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Pauline Lee
- Shiley Eye Institute, University of California San Diego, La Jolla, California
| | - S Amer Riazuddin
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Radha Ayyagari
- Shiley Eye Institute, University of California San Diego, La Jolla, California;
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17
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Hartel BP, Löfgren M, Huygen PLM, Guchelaar I, Lo-A-Njoe Kort N, Sadeghi AM, van Wijk E, Tranebjærg L, Kremer H, Kimberling WJ, Cremers CWRJ, Möller C, Pennings RJE. A combination of two truncating mutations in USH2A causes more severe and progressive hearing impairment in Usher syndrome type IIa. Hear Res 2016; 339:60-8. [PMID: 27318125 DOI: 10.1016/j.heares.2016.06.008] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 05/31/2016] [Accepted: 06/13/2016] [Indexed: 11/29/2022]
Abstract
OBJECTIVES Usher syndrome is an inherited disorder that is characterized by hearing impairment (HI), retinitis pigmentosa, and in some cases vestibular dysfunction. Usher syndrome type IIa is caused by mutations in USH2A. HI in these patients is highly heterogeneous and the present study evaluates the effects of different types of USH2A mutations on the audiometric phenotype. Data from two large centres of expertise on Usher Syndrome in the Netherlands and Sweden were combined in order to create a large combined sample of patients to identify possible genotype-phenotype correlations. DESIGN A retrospective study on HI in 110 patients (65 Dutch and 45 Swedish) genetically diagnosed with Usher syndrome type IIa. We used methods especially designed for characterizing and testing differences in audiological phenotype between patient subgroups. These methods included Age Related Typical Audiograms (ARTA) and a method to evaluate the difference in the degree of HI developed throughout life between subgroups. RESULTS Cross-sectional linear regression analysis of last-visit audiograms for the best hearing ear demonstrated a gradual decline of hearing over decades. The congenital level of HI was in the range of 16-33 dB at 0.25-0.5 kHz, and in the range of 51-60 dB at 1-8 kHz. The annual threshold deterioration was in the range of 0.4-0.5 dB/year at 0.25-2 kHz and in the range of 0.7-0.8 dB/year at 4-8 kHz. Patients with two truncating mutations, including homozygotes for the common c.2299delG mutation, developed significantly more severe HI throughout life than patients with one truncating mutation combined with one nontruncating mutation, and patients with two nontruncating mutations. CONCLUSIONS The results have direct implications for patient counselling in terms of prognosis of hearing and may serve as baseline measures for future (genetic) therapeutic interventions.
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Affiliation(s)
- Bas P Hartel
- Department of Otorhinolaryngology, Radboud University Medical Center, Nijmegen, The Netherlands; Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands.
| | - Maria Löfgren
- Swedish Institute for Disability Research (SIDR) Linköping, Sweden; Audiological Research Centre, Örebro University Hospital, Örebro, Sweden; School of Medicine and Health, Örebro University, Örebro, Sweden
| | - Patrick L M Huygen
- Department of Otorhinolaryngology, Radboud University Medical Center, Nijmegen, The Netherlands; Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Iris Guchelaar
- Department of Otorhinolaryngology, Radboud University Medical Center, Nijmegen, The Netherlands; Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Nicole Lo-A-Njoe Kort
- Department of Otorhinolaryngology, Radboud University Medical Center, Nijmegen, The Netherlands; Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Andre M Sadeghi
- The Sahlgrenska Academy, Institute of Neuroscience and Physiology, Department of Audiology, Göteborg, Sweden; Hearing and Deafness Activities Organization, Habilitation & Health, Göteborg, Sweden
| | - Erwin van Wijk
- Department of Otorhinolaryngology, Donders Institute for Brain, Cognition and Behaviour, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Lisbeth Tranebjærg
- Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark; Department of Otorhinolaryngology, Head and Neck Surgery and Audiology, Bispebjerg Hospital/Rigshospitalet, Copenhagen, Denmark
| | - Hannie Kremer
- Department of Otorhinolaryngology, Donders Institute for Brain, Cognition and Behaviour, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands; Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - William J Kimberling
- Department of Otolaryngology, Molecular Otolaryngology, and Renal Research Laboratories, University of Iowa, Iowa City, IA, USA
| | - Cor W R J Cremers
- Department of Otorhinolaryngology, Radboud University Medical Center, Nijmegen, The Netherlands; Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Claes Möller
- Swedish Institute for Disability Research (SIDR) Linköping, Sweden; Audiological Research Centre, Örebro University Hospital, Örebro, Sweden; School of Medicine and Health, Örebro University, Örebro, Sweden
| | - Ronald J E Pennings
- Department of Otorhinolaryngology, Donders Institute for Brain, Cognition and Behaviour, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
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Dinculescu A, Stupay RM, Deng WT, Dyka FM, Min SH, Boye SL, Chiodo VA, Abrahan CE, Zhu P, Li Q, Strettoi E, Novelli E, Nagel-Wolfrum K, Wolfrum U, Smith WC, Hauswirth WW. AAV-Mediated Clarin-1 Expression in the Mouse Retina: Implications for USH3A Gene Therapy. PLoS One 2016; 11:e0148874. [PMID: 26881841 PMCID: PMC4755610 DOI: 10.1371/journal.pone.0148874] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2015] [Accepted: 01/23/2016] [Indexed: 02/07/2023] Open
Abstract
Usher syndrome type III (USH3A) is an autosomal recessive disorder caused by mutations in clarin-1 (CLRN1) gene, leading to progressive retinal degeneration and sensorineural deafness. Efforts to develop therapies for preventing photoreceptor cell loss are hampered by the lack of a retinal phenotype in the existing USH3 mouse models and by conflicting reports regarding the endogenous retinal localization of clarin-1, a transmembrane protein of unknown function. In this study, we used an AAV-based approach to express CLRN1 in the mouse retina in order to determine the pattern of its subcellular localization in different cell types. We found that all major classes of retinal cells express AAV-delivered CLRN1 driven by the ubiquitous, constitutive small chicken β-actin promoter, which has important implications for the design of future USH3 gene therapy studies. Within photoreceptor cells, AAV-expressed CLRN1 is mainly localized at the inner segment region and outer plexiform layer, similar to the endogenous expression of other usher proteins. Subretinal delivery using a full strength viral titer led to significant loss of retinal function as evidenced by ERG analysis, suggesting that there is a critical limit for CLRN1 expression in photoreceptor cells. Taken together, these results suggest that CLRN1 expression is potentially supported by a variety of retinal cells, and the right combination of AAV vector dose, promoter, and delivery method needs to be selected to develop safe therapies for USH3 disorder.
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Affiliation(s)
- Astra Dinculescu
- Ophthalmology, University of Florida, Gainesville, FL, United States of America
- * E-mail:
| | - Rachel M. Stupay
- Ophthalmology, University of Florida, Gainesville, FL, United States of America
| | - Wen-Tao Deng
- Ophthalmology, University of Florida, Gainesville, FL, United States of America
| | - Frank M. Dyka
- Ophthalmology, University of Florida, Gainesville, FL, United States of America
| | - Seok-Hong Min
- Ophthalmology, University of Florida, Gainesville, FL, United States of America
| | - Sanford L. Boye
- Ophthalmology, University of Florida, Gainesville, FL, United States of America
| | - Vince A. Chiodo
- Ophthalmology, University of Florida, Gainesville, FL, United States of America
| | - Carolina E. Abrahan
- Ophthalmology, University of Florida, Gainesville, FL, United States of America
| | - Ping Zhu
- Ophthalmology, University of Florida, Gainesville, FL, United States of America
| | - Qiuhong Li
- Ophthalmology, University of Florida, Gainesville, FL, United States of America
| | | | | | - Kerstin Nagel-Wolfrum
- Cell and Matrix Biology, Institute of Zoology, Johannes Gutenberg-University of Mainz, Mainz, Germany
| | - Uwe Wolfrum
- Cell and Matrix Biology, Institute of Zoology, Johannes Gutenberg-University of Mainz, Mainz, Germany
| | - W. Clay Smith
- Ophthalmology, University of Florida, Gainesville, FL, United States of America
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Novel and recurrent CIB2 variants, associated with nonsyndromic deafness, do not affect calcium buffering and localization in hair cells. Eur J Hum Genet 2015; 24:542-9. [PMID: 26173970 DOI: 10.1038/ejhg.2015.157] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Revised: 05/20/2015] [Accepted: 06/07/2015] [Indexed: 12/18/2022] Open
Abstract
Variants in CIB2 can underlie either Usher syndrome type I (USH1J) or nonsyndromic hearing impairment (NSHI) (DFNB48). Here, a novel homozygous missense variant c.196C>T and compound heterozygous variants, c.[97C>T];[196C>T], were found, respectively, in two unrelated families of Dutch origin. Besides, the previously reported c.272 T>C functional missense variant in CIB2 was identified in two families of Pakistani origin. The missense variants are demonstrated not to affect subcellular localization of CIB2 in vestibular hair cells in ex vivo expression experiments. Furthermore, these variants do not affect the ATP-induced calcium responses in COS-7 cells. However, based on the residues affected, the variants are suggested to alter αIIβ integrin binding. HI was nonsyndromic in all four families. However, deafness segregating with the c.272T>C variant in one Pakistani family is remarkably less severe than that in all other families with this mutation. Our results contribute to the insight in genotype-phenotype correlations of CIB2 mutations.
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20
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Toms M, Bitner-Glindzicz M, Webster A, Moosajee M. Usher syndrome: a review of the clinical phenotype, genes and therapeutic strategies. EXPERT REVIEW OF OPHTHALMOLOGY 2015. [DOI: 10.1586/17469899.2015.1033403] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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21
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Aparisi MJ, Aller E, Fuster-García C, García-García G, Rodrigo R, Vázquez-Manrique RP, Blanco-Kelly F, Ayuso C, Roux AF, Jaijo T, Millán JM. Targeted next generation sequencing for molecular diagnosis of Usher syndrome. Orphanet J Rare Dis 2014; 9:168. [PMID: 25404053 PMCID: PMC4245769 DOI: 10.1186/s13023-014-0168-7] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Accepted: 10/27/2014] [Indexed: 11/17/2022] Open
Abstract
Background Usher syndrome is an autosomal recessive disease that associates sensorineural hearing loss, retinitis pigmentosa and, in some cases, vestibular dysfunction. It is clinically and genetically heterogeneous. To date, 10 genes have been associated with the disease, making its molecular diagnosis based on Sanger sequencing, expensive and time-consuming. Consequently, the aim of the present study was to develop a molecular diagnostics method for Usher syndrome, based on targeted next generation sequencing. Methods A custom HaloPlex panel for Illumina platforms was designed to capture all exons of the 10 known causative Usher syndrome genes (MYO7A, USH1C, CDH23, PCDH15, USH1G, CIB2, USH2A, GPR98, DFNB31 and CLRN1), the two Usher syndrome-related genes (HARS and PDZD7) and the two candidate genes VEZT and MYO15A. A cohort of 44 patients suffering from Usher syndrome was selected for this study. This cohort was divided into two groups: a test group of 11 patients with known mutations and another group of 33 patients with unknown mutations. Results Forty USH patients were successfully sequenced, 8 USH patients from the test group and 32 patients from the group composed of USH patients without genetic diagnosis. We were able to detect biallelic mutations in one USH gene in 22 out of 32 USH patients (68.75%) and to identify 79.7% of the expected mutated alleles. Fifty-three different mutations were detected. These mutations included 21 missense, 8 nonsense, 9 frameshifts, 9 intronic mutations and 6 large rearrangements. Conclusions Targeted next generation sequencing allowed us to detect both point mutations and large rearrangements in a single experiment, minimizing the economic cost of the study, increasing the detection ratio of the genetic cause of the disease and improving the genetic diagnosis of Usher syndrome patients.
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Affiliation(s)
- María J Aparisi
- Grupo de Investigación en Enfermedades Neurosensoriales. Instituto de Investigación Sanitaria IIS-La Fe, Semisótano Escuela de Enfermería, Hospital Universitario La Fe, Avda. Campanar, 21, 46009, Valencia, Spain. .,CIBER de Enfermedades Raras (CIBERER), Valencia, Spain.
| | - Elena Aller
- Grupo de Investigación en Enfermedades Neurosensoriales. Instituto de Investigación Sanitaria IIS-La Fe, Semisótano Escuela de Enfermería, Hospital Universitario La Fe, Avda. Campanar, 21, 46009, Valencia, Spain. .,CIBER de Enfermedades Raras (CIBERER), Valencia, Spain.
| | - Carla Fuster-García
- Grupo de Investigación en Enfermedades Neurosensoriales. Instituto de Investigación Sanitaria IIS-La Fe, Semisótano Escuela de Enfermería, Hospital Universitario La Fe, Avda. Campanar, 21, 46009, Valencia, Spain.
| | - Gema García-García
- Grupo de Investigación en Enfermedades Neurosensoriales. Instituto de Investigación Sanitaria IIS-La Fe, Semisótano Escuela de Enfermería, Hospital Universitario La Fe, Avda. Campanar, 21, 46009, Valencia, Spain. .,CHU Montpellier, Laboratoire de Génétique Moléculaire and Inserm, U827, Montpellier, F-34000, France.
| | - Regina Rodrigo
- Grupo de Investigación en Enfermedades Neurosensoriales. Instituto de Investigación Sanitaria IIS-La Fe, Semisótano Escuela de Enfermería, Hospital Universitario La Fe, Avda. Campanar, 21, 46009, Valencia, Spain. .,CIBER de Enfermedades Raras (CIBERER), Valencia, Spain.
| | - Rafael P Vázquez-Manrique
- Grupo de Investigación en Enfermedades Neurosensoriales. Instituto de Investigación Sanitaria IIS-La Fe, Semisótano Escuela de Enfermería, Hospital Universitario La Fe, Avda. Campanar, 21, 46009, Valencia, Spain. .,CIBER de Enfermedades Raras (CIBERER), Valencia, Spain.
| | - Fiona Blanco-Kelly
- CIBER de Enfermedades Raras (CIBERER), Valencia, Spain. .,Servicio de Genética, IIS - Fundación Jiménez Díaz, University Hospital, UAM, Madrid, Spain.
| | - Carmen Ayuso
- CIBER de Enfermedades Raras (CIBERER), Valencia, Spain. .,Servicio de Genética, IIS - Fundación Jiménez Díaz, University Hospital, UAM, Madrid, Spain.
| | - Anne-Françoise Roux
- CHU Montpellier, Laboratoire de Génétique Moléculaire and Inserm, U827, Montpellier, F-34000, France.
| | - Teresa Jaijo
- Grupo de Investigación en Enfermedades Neurosensoriales. Instituto de Investigación Sanitaria IIS-La Fe, Semisótano Escuela de Enfermería, Hospital Universitario La Fe, Avda. Campanar, 21, 46009, Valencia, Spain. .,CIBER de Enfermedades Raras (CIBERER), Valencia, Spain.
| | - José M Millán
- Grupo de Investigación en Enfermedades Neurosensoriales. Instituto de Investigación Sanitaria IIS-La Fe, Semisótano Escuela de Enfermería, Hospital Universitario La Fe, Avda. Campanar, 21, 46009, Valencia, Spain. .,CIBER de Enfermedades Raras (CIBERER), Valencia, Spain. .,Unidad de Genética y Diagnóstico Prenatal, Hospital Universitario y Politécnico La Fe, Valencia, Spain.
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Gao X, Wang GJ, Yuan YY, Xin F, Han MY, Lu JQ, Zhao H, Yu F, Xu JC, Zhang MG, Dong J, Lin X, Dai P. Novel compound heterozygous mutations in MYO7A Associated with Usher syndrome 1 in a Chinese family. PLoS One 2014; 9:e103415. [PMID: 25080338 PMCID: PMC4117490 DOI: 10.1371/journal.pone.0103415] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Accepted: 06/28/2014] [Indexed: 11/19/2022] Open
Abstract
Usher syndrome is an autosomal recessive disease characterized by sensorineural hearing loss, age-dependent retinitis pigmentosa (RP), and occasionally vestibular dysfunction. The most severe form is Usher syndrome type 1 (USH1). Mutations in the MYO7A gene are responsible for USH1 and account for 29–55% of USH1 cases. Here, we characterized a Chinese family (no. 7162) with USH1. Combining the targeted capture of 131 known deafness genes, next-generation sequencing, and bioinformatic analysis, we identified two deleterious compound heterozygous mutations in the MYO7A gene: a reported missense mutation c.73G>A (p.G25R) and a novel nonsense mutation c.462C>A (p.C154X). The two compound variants are absent in 219 ethnicity-matched controls, co-segregates with the USH clinical phenotypes, including hearing loss, vestibular dysfunction, and age-dependent penetrance of progressive RP, in family 7162. Therefore, we concluded that the USH1 in this family was caused by compound heterozygous mutations in MYO7A.
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Affiliation(s)
- Xue Gao
- Department of Otolaryngology, Head and Neck Surgery, PLA General Hospital, Beijing, P. R. China
- Department of Otolaryngology, Hainan Branch of PLA General Hospital, Sanya, P. R. China
- Department of Otolaryngology, the Second Artillery General Hospital, Beijing, P. R. China
| | - Guo-Jian Wang
- Department of Otolaryngology, Head and Neck Surgery, PLA General Hospital, Beijing, P. R. China
- Department of Otolaryngology, Hainan Branch of PLA General Hospital, Sanya, P. R. China
| | - Yong-Yi Yuan
- Department of Otolaryngology, Head and Neck Surgery, PLA General Hospital, Beijing, P. R. China
| | - Feng Xin
- Department of Otolaryngology, Head and Neck Surgery, PLA General Hospital, Beijing, P. R. China
| | - Ming-Yu Han
- Department of Otolaryngology, Head and Neck Surgery, PLA General Hospital, Beijing, P. R. China
- Department of Otolaryngology, Hainan Branch of PLA General Hospital, Sanya, P. R. China
| | - Jing-Qiao Lu
- Department of Otolaryngology, Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - Hui Zhao
- Department of Otolaryngology, Head and Neck Surgery, PLA General Hospital, Beijing, P. R. China
- Department of Otolaryngology, Hainan Branch of PLA General Hospital, Sanya, P. R. China
| | - Fei Yu
- Department of Otolaryngology, Head and Neck Surgery, PLA General Hospital, Beijing, P. R. China
| | - Jin-Cao Xu
- Department of Otolaryngology, the Second Artillery General Hospital, Beijing, P. R. China
| | - Mei-Guang Zhang
- Department of Otolaryngology, the Second Artillery General Hospital, Beijing, P. R. China
| | - Jiang Dong
- Xi’an Research Institute of Hi_tech, Hongqing, Xi’an, Shaanxi, P. R. China
| | - Xi Lin
- Department of Otolaryngology, Emory University School of Medicine, Atlanta, Georgia, United States of America
- * E-mail: (PD); (XL)
| | - Pu Dai
- Department of Otolaryngology, Head and Neck Surgery, PLA General Hospital, Beijing, P. R. China
- Department of Otolaryngology, Hainan Branch of PLA General Hospital, Sanya, P. R. China
- * E-mail: (PD); (XL)
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Translational read-through as an alternative approach for ocular gene therapy of retinal dystrophies caused by in-frame nonsense mutations. Vis Neurosci 2014; 31:309-16. [DOI: 10.1017/s0952523814000194] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
AbstractThe eye has become an excellent target for gene therapy, and gene augmentation therapy of inherited retinal disorders has made major progress in recent years. Nevertheless, a recent study indicated that gene augmentation intervention might not stop the progression of retinal degeneration in patients. In addition, for many genes, viral-mediated gene augmentation is currently not feasible due to gene size and limited packaging capacity of viral vectors as well as expression of various heterogeneous isoforms of the target gene. Thus, alternative gene-based strategies to stop or delay the retinal degeneration are necessary. This review focuses on an alternative pharmacologic treatment strategy based on the usage of translational read-through inducing drugs (TRIDs) such as PTC124, aminoglycoside antibiotics, and designer aminoglycosides for overreading in-frame nonsense mutations. This strategy has emerged as an option for up to 30–50% of all cases of recessive hereditary retinal dystrophies. In-frame nonsense mutations are single-nucleotide alterations within the gene coding sequence resulting in a premature stop codon. Consequently, translation of such mutated genes leads to the synthesis of truncated proteins, which are unable to fulfill their physiologic functions. In this context, application of TRIDs facilitates the recoding of the premature termination codon into a sense codon, thus restoring syntheses of full-length proteins. So far, clinical trials for non-ocular diseases have been initiated for diverse TRIDs. Although the clinical outcome is not analyzed in detail, an excellent safety profile, namely for PTC124, was clearly demonstrated. Moreover, recent data demonstrated sustained read-through efficacies of nonsense mutations causing retinal degeneration, as manifested in the human Usher syndrome. In addition, a strong retinal biocompatibility for PTC124 and designer aminoglycosides has been demonstrated. In conclusion, recent progress emphasizes the potential of TRIDs as an alternative pharmacologic treatment strategy for treating nonsense mutation-based retinal disorders.
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Côté L, Dubé M, St-Onge M, Beauregard L. Helping persons with Usher syndrome type II adapt to deafblindness: An intervention program centered on managing personal goals. BRITISH JOURNAL OF VISUAL IMPAIRMENT 2013. [DOI: 10.1177/0264619613484918] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Difficulties adapting to changes in Usher syndrome type II leading to deafblindness are well known. One of the factors that may affect the adaptation process is the ability to redirect one’s life and set new goals for oneself. This article presents the results of a group intervention program centered on managing personal goals. The results of a double-multivariate repeated-measures multivariate analysis of variance (MANOVA) point to a significant partial effect on the variable “meaning of life,” while no significant change was found for the feeling of “serenity,” “self-determination,” and the “ability to set, plan, and pursue a goal.” The results of this pilot project warrant continuing the research since the intervention seems to have a positive impact on psychological well-being.
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Affiliation(s)
- Lise Côté
- Institut de réadaptation en déficience physique de Québec, Canada
| | | | | | - Line Beauregard
- Center for Interdisciplinary Research in Rehabilitation and Social Integration, Canada
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25
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Ratnam K, Västinsalo H, Roorda A, Sankila EMK, Duncan JL. Cone structure in patients with usher syndrome type III and mutations in the Clarin 1 gene. JAMA Ophthalmol 2013; 131:67-74. [PMID: 22964989 DOI: 10.1001/2013.jamaophthalmol.2] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
OBJECTIVE To study macular structure and function in patients with Usher syndrome type III (USH3) caused by mutations in the Clarin 1 gene (CLRN1). METHODS High-resolution macular images were obtained by adaptive optics scanning laser ophthalmoscopy and spectral domain optical coherence tomography in 3 patients with USH3 and were compared with those of age-similar control subjects. Vision function measures included best-corrected visual acuity, kinetic and static perimetry, and full-field electroretinography. Coding regions of the CLRN1 gene were sequenced. RESULTS CLRN1 mutations were present in all the patients; a 20-year-old man showed compound heterozygous mutations (p.N48K and p.S188X), and 2 unrelated women aged 25 and 32 years had homozygous mutations (p.N48K). Best-corrected visual acuity ranged from 20/16 to 20/40, with scotomas beginning at 3° eccentricity. The inner segment-outer segment junction or the inner segment ellipsoid band was disrupted within 1° to 4° of the fovea, and the foveal inner and outer segment layers were significantly thinner than normal. Cones near the fovea in patients 1 and 2 showed normal spacing, and the preserved region ended abruptly. Retinal pigment epithelial cells were visible in patient 3 where cones were lost. CONCLUSIONS Cones were observed centrally but not in regions with scotomas, and retinal pigment epithelial cells were visible in regions without cones in patients with CLRN1 mutations. High-resolution measures of retinal structure demonstrate patterns of cone loss associated with CLRN1 mutations. CLINICAL RELEVANCE These findings provide insight into the effect of CLRN1 mutations on macular cone structure, which has implications for the development of treatments for USH3. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00254605.
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Affiliation(s)
- Kavitha Ratnam
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA 94143-0730, USA
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26
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Faundes V, Pardo RA, Castillo Taucher S. Genética de la sordera congénita. Med Clin (Barc) 2012; 139:446-51. [DOI: 10.1016/j.medcli.2012.02.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Revised: 02/14/2012] [Accepted: 02/23/2012] [Indexed: 10/28/2022]
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27
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Fakin A, Jarc-Vidmar M, Glavač D, Bonnet C, Petit C, Hawlina M. Fundus autofluorescence and optical coherence tomography in relation to visual function in Usher syndrome type 1 and 2. Vision Res 2012; 75:60-70. [PMID: 23000274 DOI: 10.1016/j.visres.2012.08.017] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Revised: 08/23/2012] [Accepted: 08/27/2012] [Indexed: 11/19/2022]
Abstract
Purpose of this study was to characterize retinal disease in Usher syndrome using fundus autofluorescence and optical coherence tomography. Study included 54 patients (26 male, 28 female) aged 7-70 years. There were 18 (33%) USH1 and 36 (67%) USH2 patients. 49/52 (94%) patients were found to carry at least one mutation in Usher genes. Ophthalmological examination included assessment of Snellen visual acuity, color vision with Ishihara tables, Goldmann visual fields (targets II/1-4 and V/4), microperimetry, fundus autofluorescence imaging and optical coherence tomography. Average age at disease onset (nyctalopia) was significantly lower in USH1 than USH2 patients (average 9 vs. 17 years, respectively; p<0.01); however no significant differences were found regarding type of autofluorescence patterns, frequency of foveal lesions and CME, rate of disease progression and age at legal blindness. All representative eyes had abnormal fundus autofluorescence of either hyperautofluorescent ring (55%), hyperautofluorescent foveal patch (35%) or foveal atrophy (10%). Disease duration of more than 30 years was associated with a high incidence of abnormal central fundus autofluorescence (patch or atrophy) and visual acuity loss.
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Affiliation(s)
- Ana Fakin
- Eye Hospital, University Medical Centre Ljubljana, Grablovičeva 46, 1000 Ljubljana, Slovenia.
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28
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Eisenberger T, Slim R, Mansour A, Nauck M, Nürnberg G, Nürnberg P, Decker C, Dafinger C, Ebermann I, Bergmann C, Bolz HJ. Targeted next-generation sequencing identifies a homozygous nonsense mutation in ABHD12, the gene underlying PHARC, in a family clinically diagnosed with Usher syndrome type 3. Orphanet J Rare Dis 2012; 7:59. [PMID: 22938382 PMCID: PMC3518140 DOI: 10.1186/1750-1172-7-59] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Accepted: 08/29/2012] [Indexed: 12/21/2022] Open
Abstract
Background Usher syndrome (USH) is an autosomal recessive genetically heterogeneous disorder with congenital sensorineural hearing impairment and retinitis pigmentosa (RP). We have identified a consanguineous Lebanese family with two affected members displaying progressive hearing loss, RP and cataracts, therefore clinically diagnosed as USH type 3 (USH3). Our study was aimed at the identification of the causative mutation in this USH3-like family. Methods Candidate loci were identified using genomewide SNP-array-based homozygosity mapping followed by targeted enrichment and next-generation sequencing. Results Using a capture array targeting the three identified homozygosity-by-descent regions on chromosomes 1q43-q44, 20p13-p12.2 and 20p11.23-q12, we identified a homozygous nonsense mutation, p.Arg65X, in ABHD12 segregating with the phenotype. Conclusion Mutations of ABHD12, an enzyme hydrolyzing an endocannabinoid lipid transmitter, cause PHARC (polyneuropathy, hearing loss, ataxia, retinitis pigmentosa, and early-onset cataract). After the identification of the ABHD12 mutation in this family, one patient underwent neurological examination which revealed ataxia, but no polyneuropathy. ABHD12 is not known to be related to the USH protein interactome. The phenotype of our patient represents a variant of PHARC, an entity that should be taken into account as differential diagnosis for USH3. Our study demonstrates the potential of comprehensive genetic analysis for improving the clinical diagnosis.
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Affiliation(s)
- Tobias Eisenberger
- Bioscientia Center for Human Genetics, Konrad Adenauer-Str, 17, Ingelheim 55218, Germany
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29
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Kersten FF, van Wijk E, Hetterschijt L, Bauβ K, Peters TA, Aslanyan MG, van der Zwaag B, Wolfrum U, Keunen JE, Roepman R, Kremer H. The mitotic spindle protein SPAG5/Astrin connects to the Usher protein network postmitotically. Cilia 2012; 1:2. [PMID: 23351521 PMCID: PMC3541543 DOI: 10.1186/2046-2530-1-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Accepted: 04/25/2012] [Indexed: 12/24/2022] Open
Abstract
UNLABELLED BACKGROUND Mutations in the gene for Usher syndrome 2A (USH2A) are causative for non-syndromic retinitis pigmentosa and Usher syndrome, a condition that is the most common cause of combined deaf-blindness. To gain insight into the molecular pathology underlying USH2A-associated retinal degeneration, we aimed to identify interacting proteins of USH2A isoform B (USH2AisoB) in the retina. RESULTS We identified the centrosomal and microtubule-associated protein sperm-associated antigen (SPAG)5 in the retina. SPAG5 was also found to interact with another previously described USH2AisoB interaction partner: the centrosomal ninein-like protein NINLisoB. Using In situ hybridization, we found that Spag5 was widely expressed during murine embryonic development, with prominent signals in the eye, cochlea, brain, kidney and liver. SPAG5 expression in adult human tissues was detected by quantitative PCR, which identified expression in the retina, brain, intestine, kidney and testis. In the retina, Spag5, Ush2aisoB and NinlisoB were present at several subcellular structures of photoreceptor cells, and colocalized at the basal bodies. CONCLUSIONS Based on these results and on the suggested roles for USH proteins in vesicle transport and providing structural support to both the inner ear and the retina, we hypothesize that SPAG5, USH2AisoB and NINLisoB may function together in microtubule-based cytoplasmic trafficking of proteins that are essential for cilium formation, maintenance and/or function.
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Affiliation(s)
- Ferry Fj Kersten
- Department of Human Genetics, Radboud University Nijmegen Medical Centre, 6500 HB Nijmegen, The Netherlands.
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Yang J, Wang L, Song H, Sokolov M. Current understanding of usher syndrome type II. Front Biosci (Landmark Ed) 2012; 17:1165-83. [PMID: 22201796 DOI: 10.2741/3979] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Usher syndrome is the most common deafness-blindness caused by genetic mutations. To date, three genes have been identified underlying the most prevalent form of Usher syndrome, the type II form (USH2). The proteins encoded by these genes are demonstrated to form a complex in vivo. This complex is localized mainly at the periciliary membrane complex in photoreceptors and the ankle-link of the stereocilia in hair cells. Many proteins have been found to interact with USH2 proteins in vitro, suggesting that they are potential additional components of this USH2 complex and that the genes encoding these proteins may be the candidate USH2 genes. However, further investigations are critical to establish their existence in the USH2 complex in vivo. Based on the predicted functional domains in USH2 proteins, their cellular localizations in photoreceptors and hair cells, the observed phenotypes in USH2 mutant mice, and the known knowledge about diseases similar to USH2, putative biological functions of the USH2 complex have been proposed. Finally, therapeutic approaches for this group of diseases are now being actively explored.
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Affiliation(s)
- Jun Yang
- Department of Ophthalmology and Visual Sciences, Moran Eye Center, University of Utah, Salt Lake City, Utah 84132
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Khan MI, Kersten FFJ, Azam M, Collin RWJ, Hussain A, Shah STA, Keunen JEE, Kremer H, Cremers FPM, Qamar R, den Hollander AI. CLRN1 mutations cause nonsyndromic retinitis pigmentosa. Ophthalmology 2011; 118:1444-8. [PMID: 21310491 DOI: 10.1016/j.ophtha.2010.10.047] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Revised: 10/26/2010] [Accepted: 10/28/2010] [Indexed: 10/18/2022] Open
Abstract
OBJECTIVE To describe the mutations in the CLRN1 gene in patients from 2 consanguineous Pakistani families diagnosed with autosomal recessive retinitis pigmentosa (arRP). DESIGN Case-series study. PARTICIPANTS Affected and unaffected individuals of 2 consanguineous Pakistani families and 90 unaffected controls from the same population. Informed consent was obtained from participants and the protocol was approved by a local institutional review board. METHODS Patients of 2 consanguineous families were genotyped with single-nucleotide polymorphism microarrays for genome-wide linkage analysis. The search for potential candidate genes within the 8-Mb overlapping homozygous region in these families revealed the presence of CLRN1, a gene previously known to cause Usher's syndrome type III (USH3), which was analyzed by direct sequence analysis. The clinical diagnosis was based on the presence of night blindness, fundoscopic findings, and electroretinography (ERG) results. Additionally, pure tone audiometry was performed to rule out Usher's syndrome. MAIN OUTCOME MEASURES Fundoscopy, single-nucleotide polymorphism microarray, DNA sequence analysis, ERG, and audiometry. RESULTS Sequencing of CLRN1 revealed novel missense mutations (p.Pro31Leu and p.Leu154Trp) segregating in 2 families. Analysis of fundus photographs indicated attenuation of the retinal vessels, and bone spicule pigmentation in the periphery of the retina. The ERG responses were indicative of a rod-cone pattern of the disease. Audiometric assessment revealed no hearing impairment, thereby excluding Usher's syndrome. Subcellular localization studies demonstrated the retention of the mutant proteins in the endoplasmic reticulum, whereas the wild-type protein was mainly present at the cell membrane. CONCLUSIONS The RP-associated mutations p.Pro31Leu and p.Leu154Trp may represent hypomorphic mutations, because the substituted amino acids located in the transmembrane domains remain polar, whereas more severe changes have been detected in patients with USH3. These data indicate that mutations in CLRN1 are associated not only with USH3, but also with nonsyndromic arRP.
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Affiliation(s)
- Muhammad Imran Khan
- Department of Biosciences, COMSATS Institute of Information Technology, Islamabad, Pakistan
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Distinct neuropathologic phenotypes after disrupting the chloride transport proteins ClC-6 or ClC-7/Ostm1. J Neuropathol Exp Neurol 2010; 69:1228-46. [PMID: 21107136 DOI: 10.1097/nen.0b013e3181ffe742] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The proteins ClC-6 and ClC-7 are expressed in the endosomal-lysosomal system. Because Clcn6-deficient mice display some features of neuronal ceroid lipofuscinosis (NCL), CLCN6 may be a candidate gene for novel forms of NCL. Using landmarks of disease progression from NCL mouse models as a guide, we examined neuropathologic alterations in the central nervous system of Clcn6(-/-), Clcn7(-/-), andgl mice. gl mice bear a mutation in Ostm1, the β-subunit critical for Clcn7 function. Severely affected Clcn7(-/-) and gl mice have remarkably similar neuropathologic phenotypes, with pronounced reactive changes and neuron loss in the thalamocortical system, similar to findings in early-onset forms of NCL. In contrast, Clcn6(-/-) mice display slowly progressive, milder neuropathologic features with very little thalamic involvement or microglial activation. These findings detail for the first time the markedly different neuropathologic consequences of mutations in these two CLC genes. Clcn7(-/-) and gl mice bear a close resemblance to the progressive neuropathologic phenotypes of early onset forms of NCL, whereas the distinct phenotype of Clcn6-deficient mice suggests that this gene could be a candidate for a later-onset form of mild neurologic dysfunction with some NCL-like features.
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Loss of Cav1.3 (CACNA1D) function in a human channelopathy with bradycardia and congenital deafness. Nat Neurosci 2010; 14:77-84. [DOI: 10.1038/nn.2694] [Citation(s) in RCA: 208] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2010] [Accepted: 10/25/2010] [Indexed: 01/07/2023]
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Vaché C, Besnard T, Blanchet C, Baux D, Larrieu L, Faugère V, Mondain M, Hamel C, Malcolm S, Claustres M, Roux AF. Nasal epithelial cells are a reliable source to study splicing variants in Usher syndrome. Hum Mutat 2010; 31:734-41. [PMID: 20513143 DOI: 10.1002/humu.21255] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
We have shown that nasal ciliated epithelium, which can be easily biopsied under local anesthetic, provides a good source of RNA transcripts from eight of the nine known genes that cause Usher syndrome, namely, MYO7A, USH1C, CDH23, PCDH15, USH1G for Usher type 1, and USH2A, GPR98, WHRN for Usher type 2. Furthermore, the known or predicted effect on mRNA splicing of eight variants was faithfully reproduced in the biopsied sample as measured by nested RT-PCR. These included changes at the canonical acceptor site, changes within the noncanonical acceptor site and both synonymous and nonsynonymous amino acid changes. This shows that mRNA analysis by this method will help in assessing the pathogenic effect of variants, which is a major problem in the molecular diagnosis of Usher syndrome.
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Affiliation(s)
- Christel Vaché
- CHU Montpellier, Laboratoire de Génétique Moléculaire, Montpellier, France
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Abstract
Clarin 1 (CLRN1) is a four-transmembrane protein expressed in cochlear hair cells and neural retina, and when mutated it causes Usher syndrome type 3 (USH3). The main human splice variant of CLRN1 is composed of three exons that code for a 232-aa protein. In this study, we aimed to refine the structure of CLRN1 by an examination of transcript splice variants and promoter regions. Analysis of human retinal cDNA revealed 11 CLRN1 splice variants, of which 5 have not been previously reported. We studied the regulation of gene expression by several promoter domains using a luciferase assay, and identified 1000 nt upstream of the translation start site of the primary CLRN1 splice variant as the principal promoter region. Our results suggest that the CLRN1 gene is significantly more complex than previously described. The complexity of the CLRN1 gene and the identification of multiple splice variants may partially explain why mutations in CLRN1 result in substantial variation in clinical phenotype.
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Ebermann I, Phillips JB, Liebau MC, Koenekoop RK, Schermer B, Lopez I, Schäfer E, Roux AF, Dafinger C, Bernd A, Zrenner E, Claustres M, Blanco B, Nürnberg G, Nürnberg P, Ruland R, Westerfield M, Benzing T, Bolz HJ. PDZD7 is a modifier of retinal disease and a contributor to digenic Usher syndrome. J Clin Invest 2010; 120:1812-23. [PMID: 20440071 DOI: 10.1172/jci39715] [Citation(s) in RCA: 174] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2009] [Accepted: 02/24/2010] [Indexed: 01/24/2023] Open
Abstract
Usher syndrome is a genetically heterogeneous recessive disease characterized by hearing loss and retinitis pigmentosa (RP). It frequently presents with unexplained, often intrafamilial, variability of the visual phenotype. Although 9 genes have been linked with Usher syndrome, many patients do not have mutations in any of these genes, suggesting that there are still unidentified genes involved in the syndrome. Here, we have determined that mutations in PDZ domain-containing 7 (PDZD7), which encodes a homolog of proteins mutated in Usher syndrome subtype 1C (USH1C) and USH2D, contribute to Usher syndrome. Mutations in PDZD7 were identified only in patients with mutations in other known Usher genes. In a set of sisters, each with a homozygous mutation in USH2A, a frame-shift mutation in PDZD7 was present in the sister with more severe RP and earlier disease onset. Further, heterozygous PDZD7 mutations were present in patients with truncating mutations in USH2A, G protein-coupled receptor 98 (GPR98; also known as USH2C), and an unidentified locus. We validated the human genotypes using zebrafish, and our findings were consistent with digenic inheritance of PDZD7 and GPR98, and with PDZD7 as a retinal disease modifier in patients with USH2A. Pdzd7 knockdown produced an Usher-like phenotype in zebrafish, exacerbated retinal cell death in combination with ush2a or gpr98, and reduced Gpr98 localization in the region of the photoreceptor connecting cilium. Our data challenge the view of Usher syndrome as a traditional Mendelian disorder and support the reclassification of Usher syndrome as an oligogenic disease.
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Affiliation(s)
- Inga Ebermann
- Institute of Human Genetics, University Hospital of Cologne, Cologne, Germany
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McMillan DR, White PC. Studies on the very large G protein-coupled receptor: from initial discovery to determining its role in sensorineural deafness in higher animals. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 706:76-86. [PMID: 21618827 DOI: 10.1007/978-1-4419-7913-1_6] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The very large G protein-coupled receptor 1 (VLGRI), also known as MASS1 or GPR98, is most notable among the family of adhesion-GPCR for its size. Encoded by an 18.9 kb open reading frame, the approximately 700 kDa primary translation product is by far the largest GPCR and additionally, the largest cell surface protein known to date. The large ectodomain of the protein contains several repeated motifs, including some 35 calcium binding, Calx-beta repeats and seven copies of an epitempin repeat thought to be associated with the development of epilepsy. The extreme carboxy-terminus contains a consensus PDZ ligand sequence, suggesting interactions with other cytosolic or cytoskeletal proteins. At least two spontaneous and two targeted mutant mouse lines are currently known. The mutant mice present with sensitivity to audiogenic seizures but also have cochlear defects and significant, progressive hearing impairment. Although its ligand is currently unknown, VLGR1 is one of the few adhesion-GPCR family members in which mutations have been shown to be responsible for a human malady. Mutations in VLGRI in humans result in one form (2C) of Usher syndrome, the most common genetic cause of combined blindness and deafness.
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Affiliation(s)
- D Randy McMillan
- Department of Pediatrics, UT Southwestern Medical Center, Dallas, TX 75390-9063, USA.
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Mutation analysis in the long isoform of USH2A in American patients with Usher Syndrome type II. J Hum Genet 2009; 54:732-8. [PMID: 19881469 DOI: 10.1038/jhg.2009.107] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Usher syndrome type II (USH2) is an autosomal recessive disorder characterized by moderate to severe hearing impairment and progressive visual loss due to retinitis pigmentosa (RP). To identify novel mutations and determine the frequency of USH2A mutations as a cause of USH2, we have carried out mutation screening of all 72 coding exons and exon-intron splice sites of the USH2A gene. A total of 20 USH2 American probands of European descent were analyzed using single strand conformational polymorphism (SSCP) and direct sequencing methods. Ten different USH2A mutations were identified in 55% of the probands, five of which were novel mutations. The detected mutations include three missense, three frameshifts and four nonsense mutations, with c.2299delG/p.E767fs mutation, accounting for 38.9% of the pathological alleles. Two cases were homozygotes, two cases were compound heterozygotes and one case had complex allele with three variants. In seven probands, only one USH2A mutation was detected and no pathological mutation was found in the remaining eight individuals. Altogether, our data support the fact that c.2299delG/p.E767fs is indeed the most common USH2A mutation found in USH2 patients of European Caucasian background. Thus, if screening for mutations in USH2A is considered, it is reasonable to screen for the c.2299delG mutation first.
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Hilgert N, Kahrizi K, Dieltjens N, Bazazzadegan N, Najmabadi H, Smith RJH, Van Camp G. A large deletion in GPR98 causes type IIC Usher syndrome in male and female members of an Iranian family. J Med Genet 2009; 46:272-6. [PMID: 19357116 DOI: 10.1136/jmg.2008.060947] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
BACKGROUND Usher syndrome (USH) is a clinically and genetically heterogeneous disease. The three recognised clinical phenotypes (types I, II and III; USH1, USH2 and USH3) are caused by mutations in nine different genes. USH2C is characterised by moderate to severe hearing loss, retinitis pigmentosa and normal vestibular function. One earlier report describes mutations in GPR98 (VLGR1) in four families segregating this phenotype. OBJECTIVE To detect the disease-causing mutation in an Iranian family segregating USH2C. In this family, five members had a phenotype compatible with Usher syndrome, and two others had nonsyndromic hearing loss. METHODS Mutation analysis of all 90 coding exons of GPR98. RESULTS Consistent with these clinical findings, the five subjects with USH carried a haplotype linked to the USH2C locus, whereas the two subjects with nonsyndromic hearing loss did not. We identified a new mutation in GPR98 segregating with USH2C in this family. The mutation is a large deletion g.371657_507673del of exons 84 and 85, presumably leading to a frameshift. CONCLUSIONS A large GPR98 deletion of 136 017 bp segregates with USH2C in an Iranian family. To our knowledge, this is only the second report of a GPR98 mutation, and the first report on male subjects with USH2C and a GPR98 mutation.
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Affiliation(s)
- N Hilgert
- Department of Medical Genetics, University of Antwerp, Universiteitsplein 1, B-2610 Antwerp, Belgium
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Abstract
PURPOSE OF REVIEW The present review addresses the mechanisms, genetics and pathogenesis of Usher syndrome. RECENT FINDINGS Recent molecular findings have provided more information regarding the pathogenesis of this disorder and the wide phenotypic variation in both audiovestibular and/or visual systems. Evidence has begun to emerge supporting a theory of a protein interactome involving the Usher proteins in both the inner ear and the retina. This interactome appears to be important for hair cell development in the ear but its role in the retina remains unclear. SUMMARY Understanding clinical disease progression and molecular pathways is important in the progress towards developing gene therapy to prevent blindness due to Usher syndrome as well as delivering prognostic information to affected individuals.
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Hilgert N, Smith RJH, Van Camp G. Forty-six genes causing nonsyndromic hearing impairment: which ones should be analyzed in DNA diagnostics? Mutat Res 2008; 681:189-196. [PMID: 18804553 DOI: 10.1016/j.mrrev.2008.08.002] [Citation(s) in RCA: 334] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2008] [Revised: 08/04/2008] [Accepted: 08/22/2008] [Indexed: 10/21/2022]
Abstract
Hearing impairment is the most common sensory disorder, present in 1 of every 500 newborns. With 46 genes implicated in nonsyndromic hearing loss, it is also an extremely heterogeneous trait. Here, we categorize for the first time all mutations reported in nonsyndromic deafness genes, both worldwide and more specifically in Caucasians. The most frequent genes implicated in autosomal recessive nonsyndromic hearing loss are GJB2, which is responsible for more than half of cases, followed by SLC26A4, MYO15A, OTOF, CDH23 and TMC1. None of the genes associated with autosomal dominant nonsyndromic hearing loss accounts for a preponderance of cases, although mutations are somewhat more frequently reported in WFS1, KCNQ4, COCH and GJB2. Only a minority of these genes is currently included in genetic diagnostics, the selection criteria typically reflecting: (1) high frequency as a cause of deafness (i.e. GJB2); (2) association with another recognisable feature (i.e. SLC26A4 and enlarged vestibular aqueduct); or (3) a recognisable audioprofile (i.e. WFS1). New and powerful DNA sequencing technologies have been developed over the past few years, but have not yet found their way into DNA diagnostics. Implementing these technologies is likely to happen within the next 5 years, and will cause a breakthrough in terms of power and cost efficiency. It will become possible to analyze most - if not all - deafness genes, as opposed to one or a few genes currently. This ability will greatly improve DNA diagnostics, provide epidemiological data on gene-based mutation frequencies, and reveal novel genotype-phenotype correlations.
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Affiliation(s)
- Nele Hilgert
- Department of Medical Genetics, University of Antwerp (UA), Universiteitsplein 1, B-2610 Antwerp, Belgium
| | - Richard J H Smith
- Department of Otolaryngology-Head and Neck Surgery, University of Iowa, Iowa city, IA 52242, USA
| | - Guy Van Camp
- Department of Medical Genetics, University of Antwerp (UA), Universiteitsplein 1, B-2610 Antwerp, Belgium.
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An USH2A founder mutation is the major cause of Usher syndrome type 2 in Canadians of French origin and confirms common roots of Quebecois and Acadians. Eur J Hum Genet 2008; 17:80-4. [PMID: 18665195 DOI: 10.1038/ejhg.2008.143] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Congenital hearing loss affects approximately one child in 1000. About 10% of the deaf population have Usher syndrome (USH). In USH, hearing loss is complicated by retinal degeneration with onset in the first (USH1) or second (USH2) decade. In most populations, diagnostic testing is hampered by a multitude of mutations in nine genes. We have recently shown that in French Canadians from Quebec, USH1 largely results from a single USH1C founder mutation, c.216G>A ('Acadian allele'). The genetic basis of USH2 in Canadians of French descent, however, has remained elusive. Here, we have investigated nine USH2 families from Quebec and New Brunswick (the former Acadia) by haplotype analyses of the USH2A locus and sequencing of the three known USH2 genes. Seven USH2A mutations were identified in eight patients. One of them, c.4338_4339delCT, accounts for 10 out of 18 disease alleles (55.6%). This mutation has previously been reported in an Acadian USH2 family, and it was found in homozygous state in the three Acadians of our sample. As in the case of c.216G>A (USH1C), a common haplotype is associated with c.4338_4339delCT. With a limited number of molecular tests, it will now be possible in these populations to estimate whether children with congenital hearing impairment of different degrees will develop retinal disease - with important clinical and therapeutic implications. USH2 is the second example that reveals a significant genetic overlap between Quebecois and Acadians: in contrast to current understanding, other genetic disorders present in both populations are likely based on common founder mutations as well.
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Jacobson SG, Cideciyan AV, Aleman TS, Sumaroka A, Roman AJ, Gardner LM, Prosser HM, Mishra M, Bech-Hansen NT, Herrera W, Schwartz SB, Liu XZ, Kimberling WJ, Steel KP, Williams DS. Usher syndromes due to MYO7A, PCDH15, USH2A or GPR98 mutations share retinal disease mechanism. Hum Mol Genet 2008; 17:2405-15. [PMID: 18463160 DOI: 10.1093/hmg/ddn140] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Usher syndrome (USH) is a genetically heterogeneous group of autosomal recessive deaf-blinding disorders. Pathophysiology leading to the blinding retinal degeneration in USH is uncertain. There is evidence for involvement of the photoreceptor cilium, photoreceptor synapse, the adjacent retinal pigment epithelium (RPE) cells, and the Crumbs protein complex, the latter implying developmental abnormalities in the retina. Testing hypotheses has been difficult in murine USH models because most do not show a retinal degeneration phenotype. We defined the retinal disease expression in vivo in human USH using optical imaging of the retina and visual function. In MYO7A (USH1B), results from young individuals or those at early stages indicated the photoreceptor was the first detectable site of disease. Later stages showed photoreceptor and RPE cell pathology. Mosaic retinas in Myo7a-deficient shaker1 mice supported the notion that the mutant photoreceptor phenotype was cell autonomous and not secondary to mutant RPE. Humans with PCDH15 (USH1F), USH2A or GPR98 (USH2C) had a similar retinal phenotype to MYO7A (USH1B). There was no evidence of photoreceptor synaptic dysfunction and no dysplastic phenotype as in CRB1 (Crumbs homologue1) retinopathy. The results point to the photoreceptor cell as the therapeutic target for USH treatment trials, such as MYO7A somatic gene replacement therapy.
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Affiliation(s)
- Samuel G Jacobson
- Department of Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, PA 19104, USA.
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